WO2002008822A2

WO2002008822A2 - Liquid crystal display

Info

Publication number: WO2002008822A2
Application number: PCT/JP2001/006322
Authority: WO
Inventors: Kenji Nakao; Yoshinori Tanaka; Daiichi Suzuki
Original assignee: Matsushita Electric Industrial Co., Ltd.
Priority date: 2000-07-24
Filing date: 2001-07-23
Publication date: 2002-01-31
Also published as: WO2002008822A3

Abstract

A liquid crystal display comprises a liquid crystal panel including a liquid crystal layer having arranged liquid crystal molecules and sandwiched between two opposite substrates; and a drive means that changes transmittance of the liquid crystal panel according to an image signal. In the liquid crystal panel, when performing white display, transmittance at an inclination angle other than 0 degree is the largest in a transmittance distribution indicating change in transmittance with respect to change in an inclination angle with respect to a normal line of the liquid crystal panel in a predetermined direction of the liquid crystal panel.

Description

DESCRIPTION

LIQUID CRYSTAL DISPLAY, RETARDATION FILM, OPTICAL FILM, LIQUID

CRYSTAL TELEVISION, AND LIQUID CRYSTAL MONITOR

Technical Field

The present invention relates to a liquid crystal display, a retardation film and an optical film used in the liquid crystal display, and a liquid crystal television and a liquid crystal monitor comprising the liquid crystal display.

Background Art

In recent years, liquid crystal displays have rapidly and widely spread as image display apparatuses for the purpose of saving a space. Many of the liquid crystal displays are of a TN(twisted nematic) type. However, the problem associated with the TN liquid crystal display is that this display is unsuitable for display of a moving picture due to its low response speed and its viewing angle is narrow, or the like. For this reason, a variety of attempts have been made to improve the response speed of liquid crystal molecules , enlarge the viewing angle, or the like.

As one of such attempts, there has been proposed an OCB (Optically Compensated bend) liquid crystal display element to provide a liquid crystal display that has high-speed responsiveness suitable for display of the moving picture (Syadan Hougin Denki Tsushin Gattsukai Shingaku gihou EdI98-144, pl99).

The OCB liquid crystal display element comprises a liquid crystal panel comprised of two substrates on which transparent electrodes as voltage application means are respectively formed, and a liquid crystal layer sandwiched between these substrates. Alignment layers are respectively formed on the transparent electrodes and have been subjected to alignment treatment to orient the liquid crystal molecules in parallel with one another and in the same direction.

The OCB liquid crystal display element so structured is characterized in that the liquid crystal transitions from spray orientation to bend orientation by application of the voltage, and in this bend orientation state, an image is displayed. In the OCB liquid crystal display element, since the response speed of the liquid crystal molecules is greatly improved as compared to the TN liquid crystal display, the liquid crystal display suitable for display of the moving picture is realized. Since bend-orientated liquid crystal molecules are inclined in the opposite directions on upper and lower surfaces of the sandwiching substrates, they are optically compensated. As a result, the liquid crystal display with a wide viewing angle is achieved.

When observing the liquid crystal panel included in the liquid crystal display, in may cases, the user is situated in front of the liquid crystal panel (in a normal direction of the liquid crystal panel) . Accordingly, the liquid crystal display using the conventional liquid crystal display element including the OCB liquid crystal display element is designed so that the luminance in the normal direction of the liquid crystal panel is the highes . By way of example, Japanese Laid-Open Patent Publication No. Hei.7 - 49509 discloses so designed liquid crystal display. With such design, the display in the normal direction is the brightest and display preferable to the user is obtained.

However, in the conventional liquid crystal display, the liquid crystal panel becomes considerably dark when observed from the direction other than the normal direction of the liquid crystal panel, particularly in the horizontal (right and left) direction thereof of the liquid crystal display being used, as compared to that in the normal direction.

Fig. 28 is a graph showing a transmittance distribution of the liquid crystal display using the conventional TN liquid crystal display element. The transmittance distribution refers to the distribution showing the change in transmittance of the liquid crystal panel with respect to the change in an inclination angle (hereinafter referred to as an observation angle) with respect to a normal line of the liquid crystal panel in the predetermined direction of the liquid crystal panel. In Fig. 28, a longitudinal axis of the graph indicates the transmittance of the liquid crystal and a lateral axis thereof indicates the observation angle. This graph is normalized so that the transmittance is 1.0 when the normal direction of the liquid crystal panel, i.e. , the observation angle is 0 degree.

In Fig.28, G denotes a transmittance distribution in the horizontal direction of the liquid crystal panel of the liquid crystal display being used and H denotes a transmittance distribution in the vertical direction of the liquid crystal panel of the liquid crystal display. Hereinafter, the horizontal direction (vertical direction) of the liquid crystal panel of the liquid crystal display being used is simply referred to as the horizontal direction (vertical direction) of the liquid crystal panel. In Fig.28, as indicated by the transmittance distribution G in the horizontal direction of the liquid crystal panel, the transmittance decrease as the observation angle increases from 0 degrees. For this reason, as described above, sufficient brightness is not obtained in the horizontal direction of the liquid crystal panel. As known, the result is the same in VA (Vertical Alignment) liquid crystal panel and IPS (In-Plane Switching) liquid crystal display.

Fig. 29 is a view showing a transmittance distribution in the liquid crystal display using the conventional OCB liquid crystal display element. In Fig. 29, E denotes a transmittance distribution in the horizontal direction of the liquid crystal panel andF denotes a transmittance distribution in the vertical direction. As shown in Fig.29, as indicated by the transmittance distribution E in the horizontal direction of the liquid crystal panel, the transmittance significantly decreases as the observation angle increases from 0 degree, regardless of the use of the OCB liquid crystal element. For this reason, as in the case of the TN liquid crystal display element, sufficient brightness is not ensured and preferable display is not obtained in the horizontal direction of the liquid crystal panel.

In recent years, for the liquid crystal display, a large-sized liquid crystal panel has been developed and correspondingly, in many cases, a plurality of users simultaneously observe the liquid crystal panel. Particularly when the liquid crystal display is applied to the liquid crystal television, a plurality of users rather than one user simultaneously observe the television. In such cases, if sufficient brightness is not obtained in the horizontal direction of the liquid crystal panel, the users situated at positions other than the normal direction of the liquid crystal panel cannot obtain preferable display.

DISCLOSURE OF INVENTION The present invention has been directed to solving the above-described problem, and an object thereof is to provide a liquid crystal display suitable for a case in which a plurality of users simultaneously observe the display, a retardation film and an optical film used in the liquid crystal display, and a liquid crystal television and a liquid crystal monitor comprising the liquid crystal display.

To solve the above-described problem, there is provided a liquid crystal display comprising a liquid crystal panel including a liquid crystal layer having arranged liquid crystal molecules and sandwiched between two opposite substrates; and a drive means that changes transmittance of the liquid crystal panel according to an image signal, and characterized in that the liquid crystal panel is configured such that transmittance at an inclination angle other than 0 degree is the largest in a transmittance distribution indicating change in transmittance with respect to change in an inclination angle with respect to a normal line of the liquid crystal panel in a predetermined direction of the liquid crystal panel when performing white display.

With such a configuration, when a plurality of users observe the liquid crystal panel simultaneously, the users situated at a position other than the normal direction of the liquid crystal panel can obtain preferable display. The liquid crystal display suitable for the case where the plurality of users observe the liquid crystal panel simultaneously can be achieved by thus subduing the brightness in the normal direction of the liquid crystal panel.

The liquid crystal panel may be configured such that inclination angles with the largest transmittance are present substantially symmetrically with respect to zero degree.

The predetermined direction of the liquid crystal panel may be a horizontal direction of the liquid crystal panel of the liquid crystal display being used. Thereby, the sufficient brightness can be ensured when the liquid crystal panel is observed from the observation angle other than 0 degree in the horizontal direction of the liquid crystal panel.

According to the present invention, there is also provided a liquid crystal display comprising a liquid crystal panel including a liquid crystal layer having arranged liquid crystal molecules and sandwiched between two opposite substrates; and a drive means that changes transmittance of the liquid crystal panel according to an image signal, and characterized in that in the liquid crystal panel included in the liquid crystal display being used and performing white display, when comparison is made between a transmittance distribution indicating change in transmittance with respect to change in an inclination angle with respect to a normal line of the liquid crystal panel in a horizontal direction of the liquid crystal panel and a transmittance distribution indicating change in transmittance with respect to the inclination angle with respect to the normal line of the liquid crystal panel in a vertical direction of the liquid crystal panel, the transmittance of the transmittance distribution in horizontal direction is greater than the transmittance of the transmittance distribution in the vertical direction, over the whole region. When the plurality of the users observe the liquid crystal panel simultaneously, it is desirable that brighter display be obtained when observed from the observation angle other than 0 degree in the horizontal direction of the liquid crystal panel than when observed from the observation angle other than 0 degree in the vertical direction. With the above configuration, such preferable display can be achieved.

Further, there is provided a liquid crystal television comprising: the above liquid crystal display; and a tuner portion for selecting a channel of a television broadcast signal, and characterized in that the television broadcast signal of the channel selected by the tuner portion is input to the drive means as the image signal.

With such a con iguration, it is possible to obtain a liquid crystal television capable of ensuring the sufficient brightness when the liquid crystal panel is observed from the observation angle other than 0 degree in the horizontal direction of the liquid crystal panel.

Further, there is provided a liquid crystal monitor comprising: the above liquid crystal display; and a signal processing portion for processing a monitor signal, and characterized in that a monitor image signal output from the signal processing portion is input to the drive means of the liquid crystal display as the image signal.

With such a configuration, it is possible to obtain a liquid crystal monitor capable of ensuring the sufficient brightness when the liquid crystal panel is observed from the observation angle other than 0 degree in the horizontal direction of the liquid crystal panel.

In the liquid crystal display, the directions of rubbing treatment performed on the two substrates to orient the liquid crystal molecules may be parallel with each other.

In the liquid crystal display, the liquid crystal molecules may be bend-oriented. With such a configuration, it is possible to obtain an OCB liquid crystal display capable of ensuring the sufficient brightness when the liquid crystal panel is observed from the observation angle other than 0 degree in the vertical direction of the liquid crystal panel.

Also, a direction in which the liquid crystal molecules may be oriented is the vertical direction of the liquid crystal panel of the liquid crystal display being used. The liquid crystal display may further comprise: a polarizer having an absorption axis of 45 degrees with respect to the vertical direction of the liquid crystal panel of the liquid crystal display being used; and a retardation film having an anisotropic axis orthogonal to the direction in which the liquid crystal molecules are oriented.

The liquid crystal display may further comprise: a means for condensing light toward the normal direction of the liquid crystal panel. In the liquid crystal display, the liquid crystal panel may comprise a symmetrization means that substantially symmetrizes the transmittance distribution in the predetermined direction of the liquid crystal panel in black display with respect to the inclination angle of 0 degree. Thereby, insufficient black display and difference in contrast occurring when black display is performed can be eliminated.

The liquid crystal panel may comprise: a polarizer, and the symmetrization means may include a retardation film having a positive component and placed so that an anisotorpic axis thereof is parallel to an absorption axis or a transparency axis of the polarizer.

The liquid crystal displaymay further comprise: a lighting device including a light guide plate having an end surface from which light enter and a main surface from which the light emanate, and a light source provided along the end surface of the light guide plate for entering light to the end surface, and the light guide plate may have an intensity distribution indicating change in light intensity with respect to change in a position of the main surface in a plane of the main surface. The light intensity distribution may be configured to have light intensity decreasing from a central portion of the main surface to a peripheral portion thereof. Thereby, the sufficient brightness can be ensured in the central portion of the liquid crystal panel.

The liquid crystal display may further comprise: a lighting device including a light guide plate having an end surface from which light enter and a main surface from which the light emanate, and a light source provided along the end surface of the light guide plate for entering the light to the end surface, and the light guide plate may be adapted to emanate the light toward the horizontal direction of the liquid crystal panel of the liquid crystal display being used more than the light toward the vertical direction of the liquid crystal panel of the liquid crystal display being used. With such a configuration, when the liquid crystal panel is observed from the observation angle other than 0 degree in the vertical direction of the liquid crystal panel, sufficient luminance can be obtained.

Further, there is provided a liquid crystal display comprising a liquid crystal panel including a liquid crystal layer having arranged liquid crystal molecules and sandwiched between two opposite substrates; and a drive means that changes transmittance of the liquid crystal panel according to an image signal, and characterized in that the liquid crystal molecules are bend-oriented, and in the liquid crystal panel included in the liquid crystal display being used and performing white display, a luminance distribution indicating change in luminance with respect to change in an inclination angle with respect to a normal direction of the liquid crystal panel in a horizontal direction of the liquid crystal panel is substantially equal to a luminance distribution indicating change in luminance with respect to change in an inclination angle with respect to the normal direction in a vertical direction of the liquid crystal panel.

In the liquid crystal display, the liquid crystal panel may have color pixels of respective plural colors and thicknesses of the liquid crystal layer of the color pixels differ according to the colors of the respective color pixels .

With such a configuration, since electric field intensities in the liquid crystal layer in the color pixels can be made different from one another, the coloring generated by the difference in wavelengths of light can be eliminated.

In the liquid crystal display, the liquid crystal panel may comprise at least a retardation film including a negative retardation film. In the liquid crystal panel, retardation in an in-plane direction of the negative retardation film may be 100 nm to 240 nm.

In the liquid crystal display, the liquid crystal panel may be configured so that sum of retardation of the liquid crystal layer and retardation of the retardation film is 260 nm or less when performing white display.

In the liquid crystal display, the liquid crystal panel may be configured so that sum of retardation of the liquid crystal layer and retardation of the retardation film is 245 nm or less when performing white display.

In the liquid crystal display, the liquid crystal panel may be configured so that sum of retardation of the liquid crystal layer and retardation of the retardation film is 235 nm or less when performing white display. In the liquid crystal display, the liquid crystal panel may be configured so that difference between retardation of the liquid crystal layer in white display and retardation of the liquid crystal layer in black display is 260 nm or less.

In the liquid crystal display, the liquid crystal panel may be configured so that difference between retardation of the liquid crystal layer in white display and retardation of the liquid crystal layer in black display is 245 nm or less.

In the liquid crystal display, the liquid crystal panel may be configured so that difference between retardation of the liquid crystal layer in white display and retardation of the liquid crystal layer in black display is 235 nm or less.

In the liquid crystal display, the liquid crystal panel may be configured so that a modulation rate of the liquid crystal layer at the inclination angle of 0 degree is 95% or less. In the liquid crystal display, the liquid crystal panel may be configured so that a modulation rate of the liquid crystal layer at the inclination angle of 0 degree is 90% or less.

In the liquid crystal display, the liquid crystal panel may be configured so that a modulation rate of the liquid crystal layer at the inclination angle of 0 degree is 85% or less.

In the liquid crystal display, the liquid crystal panel may be configured so that the inclination angle with the largest transmittance in the transmittance distribution is 30 degrees or more. In the liquid crystal display, the liquid crystal panel may be configured so that the inclination angle with the largest transmittance in the transmittance distribution is 45 degrees or more.

In the liquid crystal display, the liquid crystal panel may be configured so that the inclination angle with the largest transmittance in the transmittance distribution is 60 degrees or more.

In the liquid crystal display, the liquid crystal panel may be configured so that the inclination angle with the largest transmittance in the transmittance distribution is 30 degrees to 60 degrees .

In the liquid crystal display, the liquid crystal panel may be configured so that difference between the largest transmittance of the transmittance distribution and the transmittance at the inclination angle of 0 degree is 5% or more.

In the liquid crystal display, the liquid crystal panel may be configured so that difference between the largest transmittance of the transmittance distribution and the transmittance at the inclination angle of 0 degree is 10% or more. In the liquid crystal display, the liquid crystal panel may be configured so that difference between the largest transmittance of the transmittance distribution and the transmittance at the inclination angle of 0 degree is 15% or more.

Still further, there is provided a liquid crystal display comprising a liquid crystal panel including a liquid crystal layer having arranged liquid crystal molecules and sandwiched between two opposite substrates; and a drive means that changes transmittance of the liquid crystal panel by applying a voltage to the liquid crystal layer according to an image signal, and characterized in that the liquid crystal panel comprises a retardation film including a negative retardation film, and the liquid crystal layer has retardation that decreases from a largest value as the voltage being applied increases, the liquid crystal molecules have parallel orientation and are configured to have bend orientation during display, and the voltage being applied or white display is set to a value lower than a voltage value corresponding to the retardation of the liquid crystal layer with the transmittance of the liquid crystal panel having a peak.

With such a configuration, the transmittance of the liquid crystal panel in white display when the inclination angle with respect to the normal line of the liquid crystal panel is 0 degree is set relatively lower.

The retardation of the liquid crystal panel may decrease as an inclination angle with respect to a normal line of the liquid crystal panel in a direction in which the liquid crystal molecules are oriented increases and the retardation of the liquid crystal panel may increase as the inclination angle in a direction perpendicular to the direction inwhich the liquid crystal molecules are oriented increases. With such a configuration, in white display, the retardation increases according to the increase in the observation angle in the direction perpendicular to the direction in which the liquid crystal molecules are oriented, and the transmittance of the liquid crystal panel has a peak at a certain observation angle. Therefore, when the liquid crystal panel is observed from the observation angle other than 0 degree in the perpendicular direction, the sufficient brightness for preferable display can be ensured.

The retardation of the retardation film may be set so that the retardation of the liquid crystal panel remains substantially unchanged if there is a change in the inclination angle with respect to the normal line of the liquid crystal panel in the direction in which the liquid crystal molecules are oriented and in the direction perpendicular to the direction in which the liquid crystal molecules are oriented, at a voltage higher than the voltage applied for white display. With such a configuration, due to a characteristic of the bend-oriented liquid crystal layer, in white display, the retardation of the liquid crystal panel may decrease according to the increase in the observation angle in the direction in which the liquid crystal molecules are oriented andmay increase according to the increase in the observation angle in the direction perpendicular to the direction inwhich the liquid crystal molecules are oriented.

In the liquid crystal display, the transmittance at the inclination angle other than 0 degree may be the largest in a transmittance distribution indicating change in the transmittance with respect to change in the inclination angle with respect to the normal line of the liquid crystal display in the direction perpendicular to the direction in which the liquid crystalmolecules are oriented.

In the liquid crystal display, the direction perpendicular to the direction in which the liquid crystal molecules are oriented may be a horizontal direction of the liquid crystal panel of the liquid crystal display being used. Thereby, the preferable display is obtained when the liquid crystal panel is observed from the observation angle other than 0 degree in the horizontal direction of the liquid crystal panel. As a result, the preferable display is obtained when a plurality of users observe the liquid crystal panel simultaneously. In the liquid crystal display, the liquid crystal molecules may be bar-shaped.

In the liquid crystal display, the negative retardation film may be constituted by discotheque liquid crystal molecules.

In the liquid crystal display, the liquid crystal panel may comprise two polarizers between which the two opposite substrates are sandwiched, and amount of light passing through a region between the two polarizers may change as the retardation of the liquid crystal layer changes, thereby causing the transmittance of the liquid crystal panel to change so as to have a peak. In the liquid crystal display, difference between a largest value of the retardation and a value for the retardation of the liquid crystal panel occurring when the voltage for white display is applied may be 40 nm or less .

In the liquid crystal display, the difference may be 30 nm or less.

In the liquid crystal display, the difference may be 15 nm or less .

Still further, there is provided a retardation film used in a liquid crystal panel included in a liquid crystal display and adapted not to generate retardation when the liquid crystal panel is observed from a direction in which an inclination angle with respect to a normal line of the liquid crystal panel is 0 degree, and characterized in that the retardation film is adapted to generate the retardation when the liquid crystal panel is observed from the inclination angle other than 0 degree in a vertical direction of the liquid crystal panel of the liquid crystal display being used, and adapted not to generate the retardation when the liquid crystal panel is observed from the inclination angle other than 0 degree in a horizontal direction of the liquid crystal panel of the liquid crystal display being used.

In the liquid crystal display, the liquid crystal panel may comprise the above retardation film.

With such a configuration, since the retardation of the liquid crystal panel in the vertical direction thereof can be increased, the sufficient brightness for preferable display can be obtained when the liquid crystal panel is observed from the observation angle other than 0 degree in the vertical direction.

Still further, there is provided an optical film used in a liquid crystal panel included in a liquid crystal display, and characterized in that the optical film is adapted not to generate coloring when the liquid crystal panel is observed from a direction in which an inclination angle with respect to a normal line of the optical film is 0 degree and adapted to generate coloring when the liquid crystal panel is observed from a direction in which the inclination angle is other than 0 degree.

The optical film may be adapted to change the coloring according to the inclination angle.

The optical film may have a mechanism for generating interference of light. The optical film may have a mechanism for generating diffraction of light.

The optical film may have a mechanism for generating refraction of light.

In the liquid crystal display, the liquid crystal panel may comprise the above optical film.

With such a configuration, since the coloring generated in the liquid crystal panel can be compensated by the optical film, preferable display can be obtained.

The optical film may be adapted to condense light toward the direction in which the inclination angle is 0 degree.

In the liquid crystal display, the optical film may be adapted to condense light toward a normal direction of the liquid crystal panel.

Since the means for compensating the coloring generated in the liquid crystal panel and the means for ensuring the brightness in the normal direction of the liquid crystal panel can be thus realized by one optical film, the liquid crystal display can be fabricated at a low cost as compared to the case where these means are realized by separate films . The optical film may be adapted to increase polarized light entered to the liquid crystal panel. Since the means for compensating the coloring generated in the liquid crystal panel and the means for increasing the polarized light can be thus realized by one optical film, the liquid crystal display can be fabricated at a low cost as compared to the case where these means are realized by separate films .

In the optical film, the mechanism for generating the interference of light may be constituted by a multi-layered film provided on a main surface of the optical film. In the optical film, the mechanism for generating the interference of light may be constituted by a cholesteric liquid crystal provided on the main surface of the optical film.

In the optical film, the mechanism for generating the diffraction of light may be constituted by a plurality of members having refractive indices different from a refractive index of the optical films provided in stripe in the main surface of the optical film.

In the optical film, the mechanism for generating the diffraction of light may be constituted by a plurality of grooves provided in stripe in the main surface of the optical film.

In the optical film, the mechanism for generating the refraction of light may be constituted by a prism sheet bonded to the main surface of the optical film.

In the optical film, the mechanism for generating the interference of light may be constituted by an interference film bonded to the main surface of the optical film, and the interference film has a cross section causing optical anisotropy in a plane of the optical film.

Still further, there is provided a liquid crystal display comprising a liquid crystal panel including a liquid crystal layer having arranged liquid crystal molecules and sandwiched between two opposite substrates; and a drive means that changes transmittance of the liquid crystal panel according to an image signal, and characterized in that the liquid crystal panel is configured such that transmittance distribution indicating change in transmittance with respect to change in an inclination angle with respect to a normal line of the liquid crystal panel in a horizontal direction of the liquid crystal panel is substantially trapezium shaped when performing white display. Still further, there is provided a liquid crystal television comprising the above liquid crystal display and a tuner portion for selecting a channel of a television broadcast signal, and characterized in that a television video signal of the channel selected by the tuner portion is input to drive means of the liquid crystal display as an image signal.

Still further, there is provided a liquid crystal monitor comprising the above liquid crystal display and a signal processing portion for processing a monitor signal, and characterized in that a monitor video signal output from the signal processing portion is input to drive means of the liquid crystal display as an image signal.

These ob ects as well as other objects , features and advantages of the invention will become apparent to those skilled in the art from the following description with reference to the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS Fig. 1 is an explanatory view showing directions in a liquid crystal panel included in a liquid crystal display according to the present invention;

Figs.2 (a), 2(b) are views showing an example of a structure of the liquid crystal panel included in the liquid crystal display according to a first embodiment, wherein Fig. 2(a) is a cross- sectional view of the liquid crystal panel, and Fig. 2(b) is an enlarged view of a liquid crystal layer portion of Fig. 2(a);

Fig. 3 is a cross-sectional view showing another example of the structure of the liquid crystal panel included in the liquid crystal panel according to the first embodiment;

Figs.4(a) -4(e) are perspective views showing an observation angle characteristic of retardation of a liquid crystal layer and retardation of retardation films in the liquid crystal panel of

Fig. 1, wherein Fig.4(a) shows the state in which a liquid crystal molecule is upright. Fig.4(b) shows the state in which the liquid crystal molecule is lying. Fig.4(c) shows the state in which an index ellipsoid is placed in parallel with a substrate. Fig. 4(d) shows a principle in which the change in the retardation of the liquid crystal layer and the change in the retardation of the retardation film with respect to the change in the observation angle offset each other, and Fig. 4(e) shows a simplified model of the liquid crystal panel under low voltage;

Fig. 5 is a graph showing an example of the relationship between transmittance of the liquid crystal panel and the retardation of the liquid crystal layer, and an applied voltage. Fig. 6 is a view showing how the liquid crystal display according to the first embodiment is set; Fig. 7 is a graph showing a transmittance distribution of the liquid crystal display according to the first embodiment;

Fig. 8 is a plan view showing placement directions of respective optical elements composing the liquid crystal panel included in the liquid crystal display according to a first example of the first embodiment;

Fig. 9 is a block diagram showing a structure of the liquid crystal display according to the first example of the first embodiment; Fig. 10 is a view showing the relationship among a total retardation, a modulation rate of the liquid crystal layer, and a peak position indicating an observation angle at which the transmittance is the largest in the transmittance distribution; Figs .11(a), 11(b) are views showing an example of a structure of a liquid crystal panel included in a liquid crystal display according to a second example of the first embodiment, wherein Fig.11(a) is a cross-sectional view of the liquid crystal panel and Fig. 11(b) is a plan view showing an optical characteristic of films included in the liquid crystal panel; Figs. 12(a), 12(b) are graphs showing a transmittance distribution in the horizontal direction of the liquid crystal panel when the liquid crystal display according to the second example of the first embodiment performs white display and black display, wherein Fig.12(a) is a graph of the liquid crystal display according to the first example of the first embodiment and Fig. 12(b) is a graph of the liquid crystal display according to the second example of the first embodiment;

Figs.13(a) , 13(b) are views showing a structure and function of a liquid crystal display according to a third example of the first embodiment, wherein Fig. 13(a) is a cross-sectional view schematically showing the structure of the liquid crystal display; Fig. 13(b) is a vertically cross-sectional view showing function of a prism sheet of the liquid crystal display of Fig. 13(a); and Fig.13(c) is a horizontally cross-sectional view showing function of a prism sheet of the liquid crystal display of Fig. 13(a);

Fig. 14(a) is a graph showing a light amount distribution of a backlight included in the liquid crystal display according to the third example of the first embodiment and Fig. 14(b) is a graph showing a luminance distribution of the liquid crystal panel included in the liquid crystal display according to the third example of the first embodiment;

Fig. 15 is a cross-sectional view schematically showing a structure of a liquid crystal display according to a fourth example of the first embodiment; Fig. 16 is a view for explaining a light intensity distribution in a plane of the liquid crystal panel included in the liquid crystal display according to the fourth example of the first embodiment;

Fig.17 is a cross-sectional view showing a structure of main parts of the liquid crystal panel included in the liquid crystal display according to the first embodiment and comprising a color filter;

Fig. 18 is a view showing a transmittance - applied voltage characteristic in color pixels of respective colors in the liquid crystal display according to the first embodiment;

Fig.19 is a cross-sectional view showing a structure of main parts of a liquid crystal panel included in a liquid crystal display according to a second embodiment of the present invention;

Fig. 20 is a view showing a transmittance - applied voltage characteristic in color pixels of respective colors in the liquid crystal display according to the second embodiment;

Figs. 21(a) , 21(b) are views showing a structure of a liquid crystal panel included in a liquid crystal display according to a third embodiment, wherein Fig.21 (a) is a cross-sectional view showing a structure of the liquid crystal panel and Fig.21(b) is a cross-sectional view showing another example of a structure of retardation films provided in the liquid crystal panel;

Fig.22 is a cross-sectional view schematically showing a structure of a liquid crystal display according to a fourth embodiment;

Figs .23(a) , 23(b) are views showing a structure of an optical film included in a liquid crystal display according to a fifth example of the fourth embodiment, wherein Fig.23(a) is a cross-sectional view showing an example of the structure of the optical film and Fig. 23(b) is a cross-sectional view showing another example of the structure of the optical film;

Figs.24(a) , 24(b) are views showing a structure of an optical film included in a liquid crystal display according to a sixth example of the fourth embodiment, wherein Fig.24(a) is a cross-sectional view showing an example of the structure of the optical film and Fig. 24(b) is a cross-sectional view showing another example of the structure of the optical film;

Fig. 25 is a cross-sectional view showing an optical film included in a liquid crystal display according to a seventh example of the fourth embodiment;

Fig.26 is a block diagram showing a configuration of a liquid crystal television according to the fifth embodiment;

Fig.27 is a block diagram showing a configuration of a liquid crystal monitor according to the fifth embodiment; Fig. 28 is a graph showing a transmittance distribution in a liquid crystal display using the conventional TN liquid crystal display element; and

Fig. 29 is a graph showing a transmittance distribution in the liquid crystal display using the conventional OCB liquid crystal display element.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be describedwith reference to drawings . Hereinbelow, as shown in Fig. 1, in a liquid crystal display of the embodiments of the present invention that is being used, the horizontal (right and left) direction of a liquid crystal panel 100 included in the liquid crystal is called "X-axis direction", the vertical direction thereof is called "Y-axis direction" , and the depth (front and rear) direction is called "Z-axis direction". [First Embodiment]

Figs. 2(a), 2(b) are views showing an example of a structure of a liquid crystal panel included in a liquid crystal display according to the first embodiment, wherein Fig. 2(a) is a cross-sectional view of the liquid crystal panel, and Fig. 2(b) is an enlarged view of a liquid crystal layer portion of Fig.2(a) .

Referring to Fig.2(a) , the liquid crystal panel 100 included in the liquid crystal display according to the first embodiment is structured such that two substrates, i.e., a front substrate 101 and a rear substrate 102 are placed opposite to each other through a spacer (not shown) and a liquid crystal layer 4 is placed in a gap between the front substrate 101 and the rear substrate 102. In the liquid crystal layer 4, liquid crystal molecules 210 are oriented in the vertical direction (Y-axis direction) of the liquid crystal panel 100 and have bend orientation in a Z-Y plane as shown in Fig. 2(b).

The front substrate 101 is structured such that a transparent electrode 2 and an alignment layer 3 are sequentially laminated on a rear surface of a glass substrate 1. The rear substrate 102 is structured such that a transparent electrode 7 and an alignment layer 6 are sequentially laminated on a front surface of a glass substrate 8.

A retardation film 103 is provided on a front surface of the front substrate 101. The retardation film 103 is structured such that a retardation film having a negative uniaxiality (hereinafter referred to as a negative uniaxial film) 10 is provided on a front surface of a hybrid-oriented discotheque film (hereinafter referred to as a hybrid discotheque film) 9.

A retardation filmhaving apositive uniaxiality (hereinafter referred to as a positive uniaxial film) may be added to the hybrid discotheque film 9 and the negative uniaxial film 10. Specifically, as shown in Fig. 3, a positive uniaxial film 15 may be provided on the front surface of the negative uniaxial film 10, and thereby, the retardation film 103 may be constituted by the hybrid discotheque film 9, the negative uniaxial film 10, and the positive uniaxial film 15.

A retardation film 104 composed of a hybrid discotheque film

12 and a negative uniaxial film 13 sequentially provided is provided on the rear surface of the rear substrate 102. Similarly to the above, as shown in Fig.3, a positive uniaxial film 16 may be added to the hybrid discotheque film 12 and the negative uniaxial film

13.

A polarizer 11 is provided on a front surface of the retardation film 103 and a polarizer 14 is provided on a rear surface of the retardation film 104. Subsequently, an optical characteristic of so structured liquid crystal panel 100 will be described.

In general, a characteristic value of the retardation film is represented by a retardation Re in the in-plane direction of the retardation film and a retardation Rth in the thickness direction thereof. Re and Rth are respectively calculated according to the following expressions (1) , (2) .

Re = (nx - ny) d ...(1)

Rth = ((nx + ny) / 2 - nz) ... (2) where nx, ny are refractive indices in the in-plane direction of the retardation film, nz is a refractive index in the thickness direction of the retardation film, and d is the thickness of the retardation film. Here, nx is the larger of the two refractive indices nx, ny in the in-plane direction. Hereinbelow, the direction in which the refractive index is nx is called an anisotropic axis.

When a plurality of films are laminated to be formed into one retardation film, the retardation Re of the retardation film is equal to a cumulated value of retardation Re of the respective films and the retardation Rth of the retardation film is equal to a cumulated value of retardation Rth of the respective films .

To increase the retardation Rth of the retardation films 103,

104, for example, the thicknesses of the negative uniaxial films

10, 13 may be increased. Also, to increase the retardation Rth of the retardation films 103 , 104 , anisotropy of the refractive indices of the negative uniaxial films 10, 13 may be increased.

In general, in the liquid crystal layer 4 and the retardation films 103, 104, when the observation angle changes, the retardation correspondingly changes. This observation angle characteristic of the retardation can be explained conceptually as described below. Figs.4(a) -4(e) are perspective views showing an observation angle characteristic of retardation of the liquid crystal layer 4 and the retardation of the retardation films 103, 104, wherein Fig.4(a) shows the state in which the liquid crystal molecule is upright. Fig.4(b) shows the state in which the liquid crystal molecule is lying. Fig.4(c)shows the state in which an index ellipsoid is placed in parallel with a substrate. Fig. 4(d) shows a principle in which the change in the retardation of the liquid crystal layer and the change in retardation of the retardation film with respect to the change in the observation angle offset each other and Fig. 4(e) shows a simplified model of the liquid crystal panel under a low voltage.

First of all, a general description of the retardation will be given. Referring to Fig. 4(a), the retardation of the optical medium occurs due to the refractive index anisotropy. The refractive index anisotropy of the liquid crystal molecule 201 or the index ellipsoid mentioned later occurs due to the anisotropy of its shape. Therefore, in a case where the liquid crystal molecule 201 or the index ellipsoid is observed while changing the observation angle θ toward a predetermined direction, if the anisotropy is present in the shape of the liquid crystal molecule 201 or the index ellipsoid seen from the observation direction, the retardation occurs in them. Since the retardation represents the difference in phase between components of light in two directions orthogonal to each other in a plane perpendicular to the direction in which the light travels , it has an absolute value depending on the largeness of the refractive index anisotropy of the medium and has a positive or negative sign depending on the direction of the refractive index anisotropy of the medium. Here, the sign of the retardation is not represented by positive or negative but is represented by which of these components in the two directions is a retarded phase with respect to the other. The two directions orthogonal to each other in the plane perpendicular to the direction in which the light travels are represented by the direction 305(hereinafter referred to as view point moving direction) in which an observing view point moves and the direction 306(hereinafter referred to as the view point moving plane perpendicular direction) perpendicular to the plane (plane including the observation angle θ ) in which the view point moves . As shown in Fig.4(a) , assume that the liquid crystal molecule 201 is upright. The liquid crystal molecule 201 is bar-shaped and is directed perpendicularly to the substrates 101, 102. Reference numeral 304 denotes light (hereinafter referred to as observation light) entering an eye of an observer. When the observation angle θ is 0 degree, that is, when the liquid crystal panel 100 is observed from the Z-axis direction, the liquid crystal molecule 201 looks circular, and the shape has no anisotropy. Therefore, no retardation occurs in the liquid crystal molecule 201. Then, in this state, when the view point 303 is moved so as to change the observation angle θ in the X-axis direction, the liquid crystal molecule 201 looks as having a longitudinal axis along the view point moving direction (substantially X-axis direction) 305, and therefore, the retardation in which the component in the view point moving direction 305 is retarded occurs in the molecule 201. Since the anisotropy of the shape of the liquid crystal molecule 201 seen from the observation direction increases according to an increase in the observation angle θ , the retardation of the liquid crystal molecule 201 increase according to the increase in the observation angle θ . On the other hand, when the view point 303 is moved so as to change the observation angle θ from 0 degree in the Y-axis direction, the liquid crystal molecule 201 looks as having the longitudinal axis along the view point moving direction (substantially Y-axis direction) 305, the retardation in which the component in the view point moving direction 305 is retarded occurs in the liquid crystal molecule 201. Since the anisotropy of the shape of the liquid crystal molecule 201 seen from the observation direction increases according to the increase in the observation angle θ , the retardation of the liquid crystal molecule 201 increase according to the increase in the observation angle θ . Referring to Fig. 4(b), assume that the liquid crystal molecule 201 is lying. The bar-shaped liquid crystal molecule 201 is parallel to the substrates 101, 102 and is directed toward the Y-axis direction. When the view point 303 is moved so as to change the observation angle θ from 0 degree in the X-axis direction, the liquid crystal molecule 201 looks as having the longitudinal axis along the view point moving plane perpendicular direction ( Y- axis direction) 306, the retardation in which the component in the view point moving plane perpendicular direction 306 is retarded occurs in the liquid crystal molecule 201. Since the shape of the liquid crystal molecule 201 seen from the observation direction hardly changes irrespective of the increase in the observation angle θ , the retardation of the liquid crystalmolecule 201 hardly changes with respect to the increase in the observation angle θ . On the other hand, when the view point 303 is moved so as to change the observation angle θ from 0 degree in the Y-axis direction, the liquid crystal molecule 201 looks as having the longitudinal axis along the view point moving direction (substantially Y-axis direction) , the retardation in which the component in the view point moving direction is retarded occurs in the liquid crystal molecule 201. Since the anisotropy of the shape of the liquid crystal molecule 201 seen from the observation direction decreases according to the increase in the observation angle θ , the retardation of the liquid crystal molecule 201 decreases according to the increase in the observation angle θ . The retardation films 103, 104 are generally constituted by discotheque films in which circular-disc shaped index ellipsoids (discotheque liquid crystal molecules) are cumulated in the thickness direction of the film. Therefore, as shown in Fig.4(c) , assume that the circular-disc shaped index ellipsoid 301 is placed in parallel with the substrate. When the observation angle θ is 0 degree, the shape of the index ellipsoid 301 seen from the observation direction has no anisotropy, and therefore, no retardation occurs in the index ellipsoid 301. Then, in this state, when the view point 303 is moved so as to change the observation angle θ in the X-axis direction, the index ellipsoid 301 looks as having a longitudinal axis along the view point moving plane perpendicular direction ( Y-axis direction) 306, the retardation in which the component in the view point moving plane perpendicular direction 306 is retarded occurs in the index ellipsoid 301. Since the anisotropy of the shape of the index ellipsoid 301 seen from the observation direction increases according to the increase in the observation angle θ , the retardation of the index ellipsoid 301 increases according to the increase in the observation angle θ . On the other hand, when the view point 303 is moved so as to change the observation angle θ from 0 degree in the Y-axis direction, the index ellipsoid 301 looks as having the longitudinal axis along the view point moving plane perpendicular direction (X-axis direction) , the retardation in which the component in the view point moving perpendicular direction 306 is retarded occurs in the index ellipsoid 301. Since the anisotropy of the shape of the index ellipsoid 301 seen from the observation angle increase according to the increase in the observation angle θ , the retardation of the index ellipsoid 301 increases according to the increase in the observation angle θ . In the OCB liquid crystal display, the liquid crystal layer 4 has a bend orientation in which liquid crystal molecules are arranged so as to be curved. This OCB liquid crystal display is characterized in that the retardation films 103, 104 composed of the hybrid discotheque films are provided as combination with the bend-oriented liquid crystal layer, and thereby, a viewing angle characteristic is improved. This structure permits the optical design in which the change in the retardation of the liquid crystal layer 4 with respect to the change in the observation angle θ is offset by the change in the retardation of the retardation films 103, 104 with respect to the change in the observation angle θ and thereby, the viewing angle characteristic hardly changes in all directions .

Hereinbelow, this principle will be explained. As shown in Fig. 4(d), assume that the bar-shaped liquid crystal molecule 201 is placed perpendicularly to the substrates 101, 102 and the index ellipsoid 301 is placed in parallel with the substrates 101, 102. When the observation angle θ is changed in the X-axis direction, the retardation in which the component in the view point moving direction (substantially X-axis direction) 305 is retarded occurs in the liquid crystal molecule 201, while the retardation in which the component in the view point moving plane perpendicular direction (Y-axis direction) 306 is retarded occurs in the index ellipsoid 301 as the retardation film. Therefore, the retardation of the liquid crystal molecule 201 and the retardation of the index ellipsoid 301 offset each other. When the observation angle θ is changed in the Y-axis direction, the retardation in which the component in the view point moving direction (substantially Y- axis direction) 305 is retarded occurs in the liquid crystal molecule 201, while the retardation in which the component in the view point moving plane perpendicular direction (X-axis direction) 306 is retarded occurs in the index ellipsoid 301. Therefore, these retardations offset each other.

In summary, when the index ellipsoid 301 is placed perpendicularly to the longitudinal axis of the bar-shaped liquid crystal molecule 201, the retardation occurring in the liquid crystal molecule 201 by the change in the observation angle θ is offset by the retardation occurring in the index ellipsoid 301 by the change in the observation angle θ .

In the bend orientation, the liquid crystal molecules 201 around the center between the substrates 101, 102 are upright as shown in Fig. 4(a). The bend-oriented molecules comprise a substantially upright molecule around the center between these substrates 101, 102, and a substantially lying molecule in the vicinity of these substrates, and the attitude of the molecules between these molecules gradually changes from the upright state around the center to the lying state in the vicinity of the substrates, which orientation is called "hybrid orientation". Based on the above consideration, placement of a plurality of index ellipsoids 301 perpendicularly to the respective longitudinal axes of the hybrid-oriented liquid crystal molecules 201 is satisfactory for offsetting the retardation occurring in the hybrid-oriented liquid crystal molecule 201 by the change in the observation angle θ . In other words, if the plurality of index ellipsoids 301 are cumulated so as to form the hybrid orientation in which their attitudes gradually change from parallel to the substrates 101, 102 to perpendicular to the substrates 101, 102, the retardation occurring in the hybrid-oriented liquid crystal molecules 201 by the change in the observation angle 0can be offset.

As should be understood, the use of the retardation films 103, 104 composed of the index ellipsoids 301 cumulated in parallel with the substrates 101, 102 and the hybrid-oriented index ellipsoids 301 can offset the retardation occurring in the liquid crystal layer 4 by the change in the observation angle θ by the retardation of the ellipsoids 301. In the retardation films 103, 104, the index ellipsoids 301 cumulated in parallel with the substrates 101, 102 correspond to the negative uniaxial films 10, 13 and the hybrid-oriented index ellipsoids 301 correspond to the hybrid discotheque films 9, 12.

However, with respect to the change in the voltage applied to the liquid crystal layer 4, the retardation of the liquid crystal layer 4 changes but the retardation of the retardation films 103, 104 do not. The optical design to prevent the change in the viewing angle characteristic in all directions is realized for only one value of the voltage applied to the liquid crystal layer 4. The inventors studied the optimization of the optical characteristic, including decision as to which display state of the liquid crystal is the most important . The result was that the viewing angle characteristic in black displaywas the most important from the ergonomic point of view. This is because the tightness of black is the most important in creation of picture and the quality of display seen from the vertical and horizontal directions is degraded if the viewing angle characteristic of black is inferior. In this embodiment, the OCB liquid crystal of the liquid crystal layer 4 is constitutedby the positive dielectric anisotropy liquid crystal, and upon application of the voltage, the liquid crystal molecules become upright with respect to the substrates 101, 102. Also, in this embodiment, a normally white method is adopted as a display method of the liquid crystal. In black display state, a relatively high voltage is applied to the liquid crystal layer 4 and the liquid crystal molecules 201 are substantially upright as shown in Fig. 4(a). In this state, the retardation of the retardation films 103 , 104 is set so that the retardation of the liquid crystal panel 100 does not change regardless of the change in the observation angle Θ in the vertical and horizontal directions of the liquid crystal panel 100.

In this case, since many of the bend-oriented liquid crystal molecules 201 are upright, the percentage of the negative uniaxial films 10, 13 to offset the retardation of these upright liquid crystal molecules 201 in the retardation films 103, 104 is set relatively high.

Subsequently, the observation angle characteristic of the retardation of the liquid crystal panel 100 including the above-described retardation films 103, 104 in white display state will be explained. In white display state, the voltage lower than that of the black display state is applied to the liquid crystal layer 4. Thereby, in the liquid crystal layer 4, the bend-oriented liquid crystal molecules 201 change from substantially upright (linear) state to curved state. As a result, the upright ones of the bend-oriented liquid crystal molecules 201 become fewer, while the parallel ones of the bend-oriented liquid crystal molecules become more.

The retardation of the hybrid-oriented liquid crystal molecules 201 is offset by the hybrid discotheque films 9, 12 according to the amount set in the black display state. In actuality. however, since the liquid crystal molecules parallel to the substrates are increased, the retardation of some of them remains unoffset .

On the other hand, the retardation of the upright liquid crystal molecules 201 is offset by the negative uniaxial films 10, 13 according to the amount set in the black display state. However, since the upright liquid crystal molecules 201 are reduced, the retardation occurring due to the negative uniaxial films 10, 13 become correspondingly excessive. The liquid crystal molecules 201 with unoffset retardation and the excessive retardation of the negative uniaxial films 10, 13 show incomplete compensation. Hereinbelow, how the incomplete compensation affects the observation angle characteristic of the retardation of the liquid crystal panel 100 will be explained. The liquid crystal molecule 201 with the unoffset retardation has an inclination with respect to Y-axis increased according to the change from the black display state to the white display state, and are generally represented by the liquid crystal molecule 201 lying in the Y-axis direction. On the other hand, the negative uniaxial films 10 , 13 with the excessive retardation are represented by the index ellipsoids 301 parallel to the substrates 101, 102, and such liquid crystal molecule 201 and index ellipsoid 301 are illustrated in Fig. 4(e). Referring to Fig. 4(a), 4(e), when the view point 303 is moved so as to change the observation angle θ in the X-axis direction, the retardation in which the component in the view point moving plane perpendicular direction (Y-axis direction) 306 is retarded occurs in the liquid crystal molecule 201 and the retardation in which the component in the view point moving plane perpendicular direction (Y-axis direction) 306 is retarded occurs in the index ellipsoid 301 as mentioned above. These retardations are added. Therefore, the total retardation of the liquid crystal molecule 201 and the index ellipsoid 301 increase according to the increase in the observation angle θ .

On the other hand, when the view point 303 is moved so as to change the observation angle θ in the Y-axis direction, the retardation in which the component in the view point moving direction (substantially Y-axis direction) 305 is retarded occurs in the liquid crystal molecule 201 and the retardation in which the component in the view point moving plane perpendicular direction (X-axis direction) 306 is retarded occurs in the index ellipsoid 301. Therefore, the retardation of the index ellipsoid 301 reduces the retardation of the liquid crystal molecule 201. As described above, the retardation of the liquid crystal molecule 201 decreases according to the increase in the observation angle θ , while the component of the retardation orthogonal to the longitudinal direction of the liquid crystal molecules 201 in the retardation of the index ellipsoid 301 increases according to the increase in the observation angle θ . Therefore, the total retardation of these rapidly decreases according to the increase in the observation angle θ .

In white display state, when the liquid crystal panel 100 is observed from a predetermined observation angle θ in the horizontal direction of the liquid crystal panel 100, the retardation of the whole liquid crystal panel 100 increases according to the increase in the observation angled . On the other hand, in the vertical direction of the liquid crystal panel 100, the retardation of the whole liquid crystal panel 100 decreases according to the increase in the observation angle θ .

Subsequently, the relationship between the transmittance and the observation angle of the liquid crystal panel 100 will be described. Hereinafter, the "retardation" refers to the retardation at the observation angle of 0 degree.

In this embodiment, with the above-identified observation angle characteristic of the liquid crystal layer 4 and the retardation films 103, 104, the retardation value for the whole liquid crystal panel 100 in white display state is set smaller than the retardation value with the largest transmittance of the liquid crystal panel 100. Specifically, the transmittance of the liquid crystal panel 100 is set to take the largest value when the retardation value of the liquid crystal layer is the largest . Also, the value for the applied voltage (hereinafter referred to as a white display voltage) required to perform white display in the liquid crystal panel 100 is set lower than that required for the largest retardation value of the liquid crystal layer 4. It is required that the white display voltage be more than the voltage at which the liquid crystal molecule 201 transition backward from the bend orientation to the spray orientation.

Figs . 5 is a graph showing an example of the relationship between transmittance of the liquid crystal panel 100 and the retardation of the liquid crystal layer 4, and the applied voltage. In Fig. 5, the longitudinal axis indicates the transmittance of the liquid crystal panel 100 and the lateral axis indicates the voltage applied to the liquid crystal panel 100. The transmittance of the liquid crystal panel 100 is expressed in terms of percentage with respect to its peak value.

As shown in Fig. 5, the retardation of the liquid crystal layer 4 decreases from the peak value of 343 nm as the appliedvoltage increases . The transmittance of the liquid crystal panel 100 changes according to the change in the retardation of the liquid crystal layer 4. The transmittance of the liquid crystal layer 100 shows its peak when the retardation of the liquid crystal layer 4 is 343 nm. As mentioned in detail later, the value resulting from the subtraction of the retardation 68 nm of the retardation films 103, 104 from the retardation of the liquid crystal layer 4 is equal to the retardation of the liquid crystal panel 100. For one user observing the liquid crystal panel 100 as usual, it is preferable that the transmittance in the normal direction of the liquid crystal panel 100 is the largest. For this purpose, when the retardation of the liquid crystal layer 4 reaches its peak, that is, the applied voltage is "a", the white display is generally performed.

The liquid crystal display according to this embodiment is designed so that the transmittance of the liquid crystal panel 100 has its peak when the retardation of the liquid crystal layer 4 is the largest , and is set so that white display is performed when the applied voltage is, for example, b, c, or d other than a. In this setting, since the retardation of the liquid crystal panel 100 increases according to the increase in the observation angle in the horizontal direction of the liquid crystal panel 100 as described above, the transmittance of the liquid crystal panel 100 reaches its peak when the observation angle reaches a certain angle. Thereby, in the liquid crystal display of this embodiment, the transmittance is higher when the liquid crystal panel 100 is observed from an observation angle other than 0 degree in the horizontal direction thereof than when observed from the normal direction thereof. Since the retardation of the liquid crystal panel 100 decreases according to the increase in the observation angle in the vertical direction of the liquid crystal panel 100, the transmittance correspondingly and monotonically decreases.

Consequently, the screen observed from the normal direction of the liquid crystal panel 100 is not the brightest . However, this embodiment embodies the liquid crystal display suitable for the case where a plurality of users simultaneously observe the liquid crystal panel 100 by performing setting so that the liquid crystal panel 100 observed from the observation angle other than 0 degree in the horizontal direction thereof brighter than that observed from the normal direction thereof. Fig. 6 is a table showing such setting, in which a relatively high voltage is applied to the liquid crystal panel 100 and a voltage lower than the voltage is applied to the liquid crystal panel 100. Refer to Fig. 6 to easily understand the above-described setting.

Fig. 7 is a graph showing the transmittance distribution of the liquid crystal display according to this embodiment. The graph is normalized so that the transmittance is 1.0 when the observation angle is 0 degree. In Fig.7, A denotes a transmittance distribution in the horizontal direction of the liquid crystal panel 100 and B denotes a transmittance distribution in the vertical direction. Referring to the transmittance distribution A of Fig. 7, the transmittance has peaks at observation angles substantially symmetric with respect to the observation angle of 0 degree. Therefore, brighter display is obtained when the liquid crystal panel 100 is observed from the observation angles of the peaks rather than observed from the observation angle of 0 degree, that is , from the normal direction of the liquid crystal panel 100. This gives sufficient brightness to each of the plurality of users simultaneously observing the liquid crystal panel 100.

As shown in Fig. 7, the transmittance distribution A is substantially-trapezium shaped. This indicates that the observation angles having transmittance equal to that of the observation angle of 0 degree are extended in the horizontal direction and the transmittance decreases when the observation angle is greater than a predetermined angle. The substantially-trapezium shaped transmittance distribution is most suitable for the situation in which a plurality of users simultaneously observe the liquid crystal panel.

The transmittance of the transmittance distribution A is higher than that of the transmittance distribution B over the whole region. This means that brighter display is obtained when the liquid crystal panel 100 is observed from the predetermined angle in the horizontal direction thereof rather than when observed from the corresponding angle in the vertical direction thereof.

It is difficult to realize the characteristic in which only the transmittance distribution in the horizontal direction of the liquid crystal panel is substantially-trapezium shaped in the mode (e.g. MVA (Multi-domain vertical Alignment) or the like) in which the orientation state of the liquid crystal is symmetric in the horizontal and vertical directions of the liquid crystal panel. In this embodiment, it is noted that the orientation state of the liquid crystal molecules 201 is unsymmetric in the vertical and horizontal directions and such orientation state is realized by using the OCB liquid crystal display element with bend orientation. The mode in which the orientation state of the liquid crystal is unsymmetric in the vertical and horizontal directions, as well as the OCB liquid crystal mode, can achieve the above-identified characteristic.

Instead of the above-described negative uniaxial films, negative biaxial films may be used as the retardation films, and thereby the above-described effect can be obtained. [First Example] A liquid crystal display according to a first example of the first embodiment comprises the above-described liquid crystal panel

100, In the retardation films 103, 104 constituting the liquid crystal panel 100, retardation Re in the in-plane direction of the films is -34 nm and the retardation in the thickness direction thereof is 160 nm. The retardation of the liquid crystal 4 is set to 68 nm for black display and set to 328 nm, 313 nm, or 303 nm for white display as mentioned later.

Fig. 8 is a plan view showing placement directions of respective optical elements constituting the liquid crystal panel 100 included in the liquid crystal display according to the first example of the first embodiment. In Fig. 8, arrows 20a, 20b respectively denote rubbing directions of the front substrate 101 and the rear substrate 102. The front substrate 101 and the rear substrate 102 have been subjected to rubbing treatment in the vertical direction (Y-axis direction) of the liquid crystal display panel 100. That is, the liquid crystal molecules 201 constituting the liquid crystal layer 4 are oriented in the vertical direction of the liquid crystal panel 100.

Referring to Fig.8 and Fig.2(a) ,arrows 20c, 20d respectively indicate anisotropic axes of the retardation films 103, 104. As shown in Fig. 8, the anisotropic axis 20c of the retardation film

103 is orthogonal to the rubbing direction 20a of the front substrate

101, i.e. , the orientation direction of the liquid crystal molecules 201. Likewise, the anisotropic axis 20d of the retardation film 104 is orthogonal to the rubbing direction 20b of the rear substrate

102, i.e. , the direction in which the liquid crystal molecules 201 are oriented.

Referring to Fig. 8 and Fig.2(a), arrows 21a and 21b respectively denote absorption axes of polarizers 11, 14. As shown in Fig. 8, the polarizers 11, 14 are placed so that each of the absorption axes 21a, 21b makes 45 degrees with respect to the vertical direction (Y-axis direction) of the liquid crystal panel 100.

Fig. 9 is a block diagram showing a structure of the liquid crystal display according to the first example of this embodiment . In Fig.9, a liquid crystal display A is of a TFT (Thin Film Transistor) type and comprises the liquid crystal panel 100, blocks (controller, gate driver, and source driver) 22, 23, 24, and a backlight (not shown) . Referring to Figs.9,2, the rear substrate 102 corresponds to the TFT substrate. The TFT substrate is structured such that the gate lines 26 and the source lines 27 are provided in matrix and a pixel electrode (not shown) and a switching element 28 are formed for each pixel defined by the gate lines 26 and the source lines 27. The gate lines 26 and the source lines 27 are respectively driven by the gate driver 23 and the source driver 24. The gate driver 23 and the source driver 24 are controlled by the controller 22.

In the liquid crystal display A so configured, the controller 22 outputs control signals to the gate driver 23 and the source driver 24, respectively, according to an image signal 25 externally input. In accordance with the control signal, the gate driver 23 outputs the gate signals to the gate lines 26, causing the switching elements 28 of respective pixels to be sequentially turned ON. At timings according to this operation, the source driver 24 inputs image (source )signals to the pixel electrodes of the respective pixels through the source lines 27. Thereby, the liquid crystal molecules 201 are modulated and the transmittance of the light emitted from the backlight changes. As a result, the users observing the liquid crystal display A see the image according to the image signal 25. Subsequently, the voltage applied when the liquid crystal display A performs white display in the liquid crystal panel 100 will be described with reference to Fig. 5.

The liquid crystal displayA employs thewhite display voltage indicated by b, c, or d of Fig. 5. As shown in Fig. 5, when the white display voltage is b, c, or d, the retardation of the liquid crystal layer 4 is 328nm, 313nm, or 303nm.

As described above, the retardation Re of the retardation films 103, 104 is -34 nm. The retardation (hereinafter referred to as total retardation) of the liquid crystal layer 4 and the retardation films 103, 104 is the sum of the retardation of the liquid crystal layer 4 and the retardation of the retardation films 103, 104. Therefore, the total retardation for white display can be calculated as (the retardation of the liquid crystal layer 4) +(-34X2). Accordingly, when the retardation of the liquid crystal layer 4 is 328 nm, 313 nm, or 303 nm, the corresponding total retardation is respectively 260 nm, 245 nm, or 235 nm.

Fig. 10 shows the relationship among the total retardation, the modulation rate of the liquid crystal layer 4, and the observation angle (hereinafter referred to as peak position) with the largest transmittance in the transmittance distribution. Here, the modulation rate of the liquid crystal layer 4 is defined as the transmittance of the liquid crystal panel 100 which is normalized as the transmittance of the polarizers 11, 14 are 100%. To ensure the moderate brightness when the liquid crystal panel 100 is observed from the observation angle other than 0 degree in the horizontal direction of the liquid crystal panel 100, it is desirable that the peak be 30 degrees or more. For this purpose, as shown in Fig. 10, the total retardation is preferably set to 260 nm or less and the modulation rate of the liquid crystal is preferably set to 95% or less. When this is expressed as the transmittance of the liquid crystal panel 100 according to the above definition, the transmittance of the liquid crystal panel 100 is preferably set to 95% or less (see Fig. 5). In this case, the difference in the transmittance of the liquid crystal panel 100 between the observation angle of 0 degree and the peak position becomes 5% or more.

When the peak is 45 degrees or more, sufficient brightness in practice can be ensured. This is because the user commonly observes the liquid crystal panel from the observation angle within 45 degrees in the horizontal direction. Therefore, as shown in Fig.10, the total retardation is preferably set to 245 nm or less and the modulation rate of the liquid crystal layer 4 is preferably set to 90% or less. When this is expressed as the transmittance of the liquid crystal panel 100 according to the above definition, the transmittance of the liquid crystal panel 100 is preferably set to 90% or less (see Fig. 5) . In this case, the difference in the transmittance of the liquid crystal panel 100 between observation angle of 0 degree and the peak position becomes 10% or more.

Further, to achieve the display equal to that of the CRT, it is desirable that the peak be 60 degrees or more. This is because the user cannot recognize the image due to distortion in its shape when the observation angle is more than 60 degrees. Therefore, as shown in Fig. 10, the total retardation is preferably set to 235 nm or less and the modulation rate of the liquid crystal layer 4 is preferably set to 85% or less . When this is expressed as the transmittance of the liquid crystal panel 100 according to the above definition, the transmittance of the liquid crystal panel 100 is preferably set to 85% or less (see Fig. 5). In this case, the difference between the transmittance of the liquid crystal panel 100 at the observation angle of 0 degree and the transmittance of the liquid crystal panel 100 at the peak position becomes 15% or more. As described above, the white display voltage needs to be greater than the voltage at which backward transition from the bend orientation to the spray orientation takes place, but a drive method for periodically applying the voltage lower than the backward transition voltage may be employed, in which case, the black display is periodically inserted. The cycle in which the black display is inserted is arbitrary. For example, the black display may occupy approximately 10% of one frame period or may occupy more than 50% of one frame period to provide sharpness of the moving picture. Instead of the insertion of the black display, the drive method for applying a bias voltage of approximately 2V may be employed. Which method is to be employed may be determined according to the set value of the white display voltage.

As should be appreciated, in the liquid crystal display A according to the first example of the first embodiment, the transmittance of the liquid crystal panel 100 is higher when the liquid crystal panel 100 is observed from the observation angle other than 0 degree in the horizontal direction thereof than when observed from the normal direction of the liquid crystal panel 100. For this reason, the liquid crystal display A is suitable for the liquid crystal television, the liquid crystal monitor, or the like which a plurality of users observe simultaneously. [Second Example]

The inventors statistically discovered the following phenomenon. When the liquid crystal panel is observed from the observation angle other than 0 degree in the vertical direction of the liquid crystal panel, the user does not feel discomfort even if upwardbrightness and downwardbrightness differ from each other. On the other hand, when the liquid crystal panel is observed from the observation angle other than 0 degree in the horizontal direction of the liquid crystal panel, the user feels discomfort if leftward brightness and rightward brightness differ from each other.

This is due to the fact that the user particularly feels difference in brightness in the horizontal direction because the image displayed in the liquid crystal panel is often symmetric in the horizontal direction thereof but the image in the vertical direction thereof is not. It is therefore desirable that the observation angles with the largest transmittance be symmetric with respect to the observation angle of 0 degree in the transmittance distribution in the horizontal direction of the liquid crystal panel.

However, when black display is performed, a phenomenon in which the transmittance sometimes increases at some observation angles in the horizontal direction of the liquid crystal panel, namely, "insufficient black display" occurs. This insufficient black display causes the difference in contrast between the leftward direction and the rightward direction. For this reason, when black display is performed, the difference in brightness is sometimes generated between the rightward direction and the leftward direction, and the user feel discomfort. Accordingly, in the second example of this embodiment, in order to eliminate the insufficient black display and difference in the contrast, retardation films having positive refractive index anisotropy were inserted into the liquid crystal panel 100. Figs.11(a) , 11(b) are views showing an example of a structure of the liquid crystal panel included in the liquid crystal display according to the second example of this embodiment, wherein Fig. 11(a) is a cross-sectional view showing the liquid crystal panel and Fig. 10(b) is a plan view showing an optical characteristic of films included in the liquid crystal panel.

In Fig. 11(a), reference numerals 17, 18 denote retardation films having positive refractive index anisotropy. The retardation film 17 is placed between the retardation film 103 and the polarizer 11 and the retardation film 18 is placed between the retardation film 104 and the polarizer 14.

In Fig. 11(b), arrow 30 denotes a transparency axis of the polarizer 11 and arrow 31 denotes its absorption axis. The retardation film 17 is placed such that its anisotropic axis is parallel to the transparency axis 30 or the absorption axis 31 of the polarizer 11. Specifically, the anisotropic axis of the retardation film 17 is indicated by arrow 32a or 32b. Likewise, the retardation film 18 is placed such that its aisotropic axis is parallel to the transparency axis or the absorption axis of the polarizer 14. Figs.12(a), 12(b) are graphs showing the transmittance distribution in the horizontal direction of the liquid crystal panel 100 that performs white display and black display, wherein Fig. 12(a) is a graph for the liquid crystal display according to the first example and Fig. 12(b) is a graph for the liquid crystal display according to the second example. In Fig.12(a) , Al denotes the transmittance distribution of the liquid crystal display according to the first example that performs white display and CI denotes the transmittance distribution of the liquid crystal display that performs black display. In Fig. 12(b), A2 denotes the transmittance distribution of the liquid crystal display according to the second example that performs white display and C2 denotes the transmittance distribution of the liquid crystal display that performs black display.

As shown in Fig. 12(a), the transmittance distribution CI is unsymmetric with respect to the observation angle of 0 degree, which is caused by the above-described insufficient black display. On the other hand, as shown in Fig. 12(b), when the transmittance distribution C2 is substantially symmetric with respect to the observation angle of 0 degree. So, when black display is performed, brightness symmetric in the horizontal direction of the liquid crystal panel 100 is ensured and the user does not feel discomfort . Instead of the above-described uniaxial films, biaxial films having refractive indices changing in the thickness direction may be employed as the retardation films. Also, they may serve as base films of the retardation films. [Third Example]

As shown in Fig. 7, the degree at which the transmittance of the transmittance distribution B in the vertical direction of the liquid crystal panel 100 decreases according to the increase in the observation angle is larger than the degree at which the transmittance of the transmittance distribution A in the horizontal direction decrease according to the increase in the observation angle, over the whole region. Accordingly, a liquid crystal display according to a third example of this embodiment is adapted to perform compensation by using the backlight.

Figs 13(a) , 13(b) are views showing the structure and function of the liquid crystal display according to the third example of this embodiment, wherein Fig. 13(a) is a cross-sectional view schematically showing the structure of the liquid crystal display, Fig. 13(b) is a vertically cross-sectional view showing a function of a prism sheet of the liquid crystal display of Fig. 13(a), and Fig.13(c) is a horizontally cross-sectional view showing a function of a prism sheet of the liquid crystal display of Fig. 13(a),. Referring to Fig. 13(a), a backlight 400 is placed behind the liquid crystal panel 100. The backlight 400 comprises a light guide plate 403 constituted by a rectangular transparent synthetic resin plate, light-emitting tubes 401 as a pair of light emitters placed in the vicinity of, along, and substantially in parallel with a pair of end faces of the light guide plate 403, a pair of reflectors 401 respectively covering the pair of light-emitting tubes 401 over substantially the whole length thereof, a prism sheet

43 placed on a front surface of the light guide plate 403, and a reflection plate 41 disposed behind the light guide plate 403.

The prism sheet 43 is configured such that one main surface thereof has concave and convex portions in the form of triangular wave and the other main surface is flat. The prism sheet 43 has a uniform cross section in the direction orthogonal to the cross section of Fig. 13(b), that is, in the direction orthogonal to the direction in which the triangular wave extends (see Fig. 13(c)). In the prism sheet 43, the direction in which the triangular wave extends corresponds with the vertical direction of the liquid crystal panel 100. The light emanating toward the horizontal direction of the liquid crystal panel 100 of the light entering from the lat main surface emanates from the triangular wave shaped main surface such that the light is condensed toward the normal direction of the liquid crystal panel 100. For this reason, the amount of light emanating toward the vertical direction of the liquid crystal panel 100 becomes larger than the amount of light emanating toward the horizontal direction thereof. As a result, the degree at which the light amount of the light amount distribution of the backlight in the vertical direction of the liquid crystal panel 100 decreases according to the increase in the observation angle is smaller than the degree at which the light amount of the light amount distribution of the backlight in the horizontal direction decreases according to the increase in the observation angle .

Figs. 14(a), 14(b) are graphs showing a light amount distribution of the backlight 400 and a luminance distribution of the liquid crystal display according to a third example of this embodiment, wherein Fig.14(a) shows the light amount distribution of he backlight 400 and Fig.14(b) shows the luminance distribution of the liquid crystal display. Here, the light amount distribution of the backlight 400 refers to the distribution indicating the change in the amount of the light emanating from the backlight 400 with respect to the change in the observation angle in the predetermined direction of the liquid crystal panel 100. The luminance distribution of he liquid crystal display refers to the distribution indicating the change in luminance of the liquid crystal display with respect to the change in the observation angle in the predetermined direction of the liquid crystal display.

These distributions are normalized so that the light amount and the luminance are equal to 1.0 when the observation angle is 0 degree, similarly to the transmittance distribution.

In Fig. 14(a), A denotes the light amount distribution of the backlight 400 in the horizontal direction of the liquid crystal panel 100 and B denotes the light amount distribution of the backlight 400 in the vertical direction. As shown in Fig. 14(a), the degree at which the light amount of the light amount distribution B decreases according to the increase in the observation angle is smaller than the degree at which the light amount of the light amount distribution A decrease according to the increase in the observation angle. This is because the provision of the prism sheet 43 makes the amount of light emanating toward the vertical direction of the liquid crystal panel 100 larger than the amount of light emanating toward the horizontal direction.

On the other hand, as described with reference to Fig. 7, the degree at which the transmittance of the transmittance distribution B in the vertical direction of the liquid crystal panel 100 decreases according to the increase in the observation angle is larger than the degree at which the transmittance of the transmittance distribution A in the horizontal direction decrease according to the increase in the observation angle, over the whole region.

Thus, the light amount distribution of the backlight 400 and the transmittance distribution of the liquid crystal panel 100 have opposite characteristics, which offset each other. The luminance distribution of the liquid crystal display is as shown in Fig.14 (b) .

In Fig.14(b), A denotes the luminance distribution of the liquid crystal display in the horizontal direction thereof and B denotes the luminance distribution of the liquid crystal display in the vertical direction thereof. As shown in Fig. 14(b), the luminance distributions A and B have similar shapes. This means that the equal brightness is obtained in the vertical and horizontal directions of the liquid crystal display. Although it was difficult to obtain the equal brightness in the vertical and horizontal directions of the liquid crystal panel 100 in the OCB liquid crystal display, due to the anisotropy of the brightness in the liquid crystal panel, the prism sheet 43 is provided as described above for preferable display in both of the directions. [Fourth Example]

When observing the liquid crystal television or the like, the user sees a central portion of the screen for most of the observation time. So, it is known that the brightness of the central portion of the screen is more important than that of a peripheral portion thereof. In actuality, in case of the CRT, the brightness in the peripheral portion of the screen is sometimes almost as half as the brightness in the central portion thereof but the user does not feel discomfort with it. Accordingly, also in the liquid crystal display of this example, it is required that the sufficient brightness in the central portion of the liquid crystal panel 100 be ensured.

Fig.15 is a cross-sectional view schematically showing the structure of the liquid crystal display according to a fourth example of this embodiment. As shown in Fig. 15, in the fourth example, the prism sheet 43 of the third example has been replaced by a dot pattern 42 provided on the front surface of the light guide plate 403 for diffusing light from the light guide plate 403. Since the other structure is identical to that of the third example, this is referenced by the same reference numerals and the detailed description thereof is omitted.

The dot pattern 42 is configured so as to have density reduced from the central portion of the light guide plate 403 to the peripheral portion thereof. The dot pattern 42 is formed by printing white-based paint or the like.

In the backlight 400 so structured, the light emitted from the light-emitting tube 401 enters the light guide plate 103 from the end face thereof directly or by reflection of the reflector 402. The light leaking to the rear surface of the light guide plate 403 is reflected on the reflector 41 and returned to the inside of the light guide plate 403. The light thus entering the light guide plate 403 is multiply reflected in the light guide plate 403 and emanates from the front surface thereof. The light emanating from the front surface of the light guide plate 403 is diffused by the dot pattern 42 and the liquid crystal panel 100 is irradiated with the diffused light .

As mentioned previously, the dot pattern 42 is formed on the front surface of the light guide plate 403 such that its density is reduced from the central portion to the peripheral portion. Therefore, as shown in Fig. 6, the liquid crystal panel 100 has a light intensity distribution in a plane thereof. The numeric values of Fig. 16 indicate the light intensities in respective portions assuming that the light intensity in the central portion of the liquid crystal panel 100 is 100%. As can be seen from Fig. 16, the intensity decreases from the central portion to the peripheral portion of the liquid crystal panel 100. Thus, the liquid crystal display according to the fourth example is capable of ensuring sufficient brightness in the central portion of the liquid crystal panel 100. Commonly, the user sees the central portion of the liquid crystal panel when observing it. Therefore, by ensuring the sufficient brightness in the central portion of the liquid crystal panel 100, the image display preferable to the user is achieved. [Second Embodiment] In the second embodiment, a liquid crystal display capable of eliminating "coloring" of the liquid crystal panel is embodied.

The liquid crystal display according to the first embodiment can be provided with color filters of three elementary colors (RED,

GREEN, BLUE) for color display. Fig. 17 is a cross-sectional view showing a structure of main parts of the liquid crystal panel 100 provided with the color filters.

Referring to Fig. 17, a RED color filter 51R, a GREEN color filter 51G, and a BLUE color filter 5IB are formed between the glass plate 1 and the transparent electrode 2. Hereinafter, pixels respectively corresponding to the color filters 51R, 51G, 51B are referred to as color pixels . Thicknesses of the liquid crystal layer 4 (hereinafter referred to as panel gaps) 53R, 53G, 53B in the color pixels of RED, GREEN, and BLUE are equal as shown in Fig. 17. Since the other structure is identical to that of the liquid crystal panel 100 of Fig.2(a), the corresponding parts are referenced to by the same reference numerals and the detailed description thereof is omitted.

As in the case of a general material, in the liquid crystal, the refractive index increases as the wavelength of light decreases . When comparison is made among the wavelengths of light of RED, GREEN, BLUE, RED has the longest wavelength and BLUE has the shortest wavelength. When comparison is made among the refractive indices of the liquid crystal layer 4 in the respective color pixels, the color pixel of RED has the smallest refractive index and the color pixel of BLUE has the largest refractive index.

Fig.18 shows a transmittance - appliedvoltage characteristic in the respective color pixels . The applied voltage with the largest transmittance is the lowest in the color pixel of RED and is the highest in the color pixel of BLUE. Consequently, the liquid crystal panel 100 is BLUE-coloredwhen observed from the observation angle other than 0 degree in the vertical direction of the liquid crystal panel 100 and is RED-colored when observed from the observation angle other than 0 degree in the horizontal direction. Accordingly, in this embodiment , the panel gaps are made to differ from one another for the respective color pixels. Fig.19 is a cross-sectional view showing a structure of main parts of the liquid crystal panel included in the liquid crystal display according to this embodiment. As in the case shown in Fig. 17, a RED color filter 61R, a GREEN color filter 61G, and a BLUE color filter 6IB are formed between the glass plate 1 and the transparent electrode 2. The panel gaps 63R, 63G, 63B of the color pixels of RED, GREEN, BLUE are set as: 63R > 63G > 63B The panel gaps have a step structure as shown in Fig. 19. With such a configuration, the electric field intensities in the liquid crystal layer 4 in the respective color pixels are: 63R < 63G < 63B

This makes it possible that the transmittance - applied voltage characteristics in the respective pixels of the respective colors can be made substantially identical. Consequently, the coloring in the liquid crystal panel 100 is eliminated and preferable display is therefore achieved. [Third Embodiment]

In a third embodiment, there is embodied a liquid crystal display capable of subduing reduction of brightness when the liquid crystal panel 100 is observed from the observation angle other than

0 degree in the vertical direction of the liquid crystal panel 100.

In the first embodiment , the brightness of the liquid crystal panel 100 observed from the observation angle other than 0 degree in the horizontal direction thereof can be improved but the brightness in the vertical direction thereof is reduced. This is due to the fact that the retardation increase according to the increase in the observation angle in the horizontal direction of the liquid crystal panel 100 but decreases in the vertical direction. Accordingly, the liquid crystal panel 100 is provided with a retardation film mentioned below.

Figs. 21(a), 21(b) are views showing the structure of the liquid crystal panel 100 included in the liquid crystal display according to this embodiment, wherein Fig. 20(a) is a cross- sectional view showing the structure of the liquid crystal panel and Fig.20(b) is a cross-sectional view showing a structure of the retardation film provided in the liquid crystal panel.

As shown in Fig. 21(a), the liquid crystal panel 100 is structured such that a retardation film 71 is provided between the front substrate 101 and the retardation film 103. As shown in Fig. 21(b) , the retardation film 71 is structured such that a retardation film 702 with bar-shaped liquid crystal molecules oriented in the horizontal direction (X-axis direction) and a negative uniaxial retardation film 701 with laminated discotheque liquid crystal are sequentially laminated on a front surface of a positive uniaxial retardation film 703.

The provision of the positive uniaxial retardation film 703 can offset the retardation in the normal direction of the liquid crystal panel 100. Also, the provision of the retardation film 702 with the bar-shaped liquid crystal molecules oriented in the horizontal direction and the negative uniaxial retardation film 701 with laminated discotheque liquid crystal can increase the retardation of the liquid crystal panel 100 when the liquid crystal panel 100 is observed from apredetermined angle other than 0 degree in the vertical direction of the liquid crystal panel 100.

Thereby, no retardation occurs in the retardation film 71 when the liquid crystal panel 100 is observed from the normal direction thereof, whereas the retardation occurs when the liquid crystal panel 100 is observed from the observation angle other than 0 degree in the vertical direction thereof. Also, no retardation occurs in the retardation film 71 when the liquid crystal panel

100 is observed from the angle other than 0 degree in the horizontal direction thereof. The liquid crystal panel 100 provided with the retardation film 71 can ensure sufficient brightness when observed from the observation angle other than 0 degree in the vertical direction of the liquid crystal panel 100.

[Fourth Embodiment] The fourth embodiment of the present invention embodies a liquid crystal display capable of eliminating coloring of the liquid crystal panel.

In the first embodiment, the brightness in the horizontal direction of the liquid crystal panel 100 can be improved but coloring is generated in the horizontal direction thereof.

Accordingly, in this embodiment, the "coloring" is eliminated by providing an optical film described below.

Fig. 22 is a cross-sectional view schematically showing a structure of a liquid crystal display according to this embodiment . Referring to Fig. 22, an optical film 81 is bonded to the front surface of the light guide plate 403 included in the backlight 400.

Since the other structure is identical to that of Fig. 13, the corresponding parts are referenced to by the same reference numerals , and the description thereof is omitted. In the optical film 81, no coloring is generated when observed from the normal direction, i.e. , from the observation angle being

0 degree, whereas coloring is generated when observed from the observation angle other than 0 degree. The optical film 81 is configured to have optical anisotropy in a plane thereof. The provision of the optical film 81 can compensate the coloring generated when the liquid crystal panel 100 is observed from the observation angle other than 0 degree in the horizontal direction of the liquid crystal panel 100. Consequently, preferable display is obtained. [Fifth Example]

In a fifth example of this embodiment, coloring is compensated by using interference of light.

Figs .23(a) , 23(b) are views showing a structure of an optical film included in a liquid crystal display according to the fifth example of this embodiment, wherein Fig. 23(a) is a cross- sectional view showing an example of a structure of the optical film and Fig. 23(b) is a cross-sectional view showing another example of the structure of the optical film.

Referring to Figs. 23, 22, an optical film 81 bonded to the front surface of the light guide plate 403 included in the backlight 400 is structured such that a multi-layered film 91 is formed on a front surface of a plastic film 92. The multi-layered film 91 is structured to have a plurality of laminated thin films having different refractive indices so that the liquid crystal panel 100 becomes transparent when observed from the normal direction of the liquid crystal panel 100, that is, the coloring is prevented.

The optical film 81 is structured such that one main surface thereof with the multi-layered film 91 deposited thereon is corrugated in the vertical direction (Y-axis direction) and the other main surface thereof is flat. The optical film 81 has a uniform cross-section in the direction orthogonal to the direction in which corrugation extends. So, when the liquid crystal panel 100 is observed from the horizontal direction of the liquid crystal panel 100, the thickness of each thin film constituting the multi-layered film 91 looks larger as the observation angle increases . For this reason, wavelength dependency of light emitted from the backlight 400 to the liquid crystal panel 100 is varied, thereby causing interference of light.

When the interference of light occurs, the coloring is generated in the optical film 81. Since the coloring offsets the coloring generated when the liquid crystal panel 100 is observed from the horizontal direction thereof, it is possible to prevent the generation of the coloring in the whole liquid crystal panel 100. When the liquid crystal panel 100 is observed in the vertical direction thereof, a thin film portion of an apparently large thickness and a thin film portion of an apparently small thickness, constituting the multi-layered film 91 coexist. Consequently, no coloring is generated in the optical ilm 81 and preferable display is obtained.

The shape of cross-section for generating the interference of light is not limited to the shape of cross-section in which the main surface with deposited multi-layered film 91 is corrugated in the vertical direction as shown in Fig. 23(a), and may be the shape of cross-section causing the optical anisotropy in the plane of the optical film 81. This optical anisotropy makes the degree of coloring different depending on the direction from which the liquid crystal panel 100 is observed, and consequently can compensate the coloring. Hence, as shown in Fig.23(b) , an optical film having a main surface with the multi-layered film 91 that includes triangularwave concave and convexportions maybe employed. Also in this case, as in the case of the corrugation of Fig.23(a) , the optical anisotropy occurs in the plane of the front surface of the optical film 81. Therefore, the coloring can be compensated. The structure of the optical film 81 is not limited to the structure in which the multi-layered film 91 is deposited on the front surface of the plastic film 92 so long as the optical film 81 obtains the interference effect of light. For example, a layered-structure of cholesteric liquid crystal may be employed to generate the interference of light, or cholesteric liquid crystals may be polymerized to be filmed. [Sixth Example]

In a sixth example, coloring is compensated by using diffraction of light. Figs.24(a) , 24(b) are views showing a structure of an optical film included in a liquid crystal display according to a sixth example of this embodiment, wherein Fig.6(a) is a cross-sectional view showing an example of a structure of the optical film and Fig. 6(b) is a cross-sectional view showing another example of the optical film.

Also referring to Fig. 22, the optical film 81 bonded to the front surface of the light guide plate 403 included in the backlight 400 is structured such that bar-shaped acrylates 93 having rectangular cross section are arranged on the front surface of a PET (polyethylene terephthalate) base film 94 at a pitch of 50 m in the horizontal direction (X-axis direction) . In other words , the acrylates 93 are formed in stripe in the horizontal direction on the front surface of the PET base film 94. Here, the refractive index of the PET base film 94 is set to 1.5, and the refractive index of the acrylate 93 is set to 1.7.

The provision of the acrylates 93 with high refractive index in stripe generates diffraction of light in the direction perpendicular to the direction in which the acrylates 93 extend. As a result, anisotropy occurs in the diffraction of light in the plane of the front surface of the optical film 81. Thereby, the diffraction effect obtained when the liquid crystal panel 100 is observed from the vertical direction of the liquid crystal panel 100 is made different from that obtained when the panel 100 is observed from the horizontal direction thereof. The use of the optical film 81 generates BLUE-coloring in the region of the YELLOW-coloring in the liquid crystal panel 100, thereby compensating the coloring.

The structure to generate the diffraction of light is not limited to the structure of Fig.24 (a) , but any structure to generate diffraction grating may be employed. For example, as shown in Fig. 24(b) , instead of the acrylates 93, grooves having rectangular cross section may be arranged in the horizontal direction (X-axis direction) of the PET base film 94 at a pitch of 50 m. As in the case where the acrylates 93 are provided, the optical anisotropy occurs in the plane of the front surface of the optical film 81. Thereby, the coloring can be compensated.

The pitch of the acrylates 93 or the grooves is not limited to 50 m, but is preferably set to 100 Mm or less because no coloring occurs when the pitch is relatively large. [Seventh Example]

In a seventh example, the coloring is compensated by utilizing refraction of light.

Fig. 25 is a cross-sectional view showing a structure of an optical film included in a liquid crystal display according to a seventh example of this embodiment. Referring to Fig. 25, the optical film 81 is a prism sheet having a front surface with triangular wave concave and convex portions. The optical film 81 has optical anisotropy in the front surface, and therefore, the coloring can be compensated. The use of the prism sheet as the optical sheet 81 is capable of condensing light in the normal direction of the liquid crystal panel 100 as described above. In other words, the optical film 81 performs the function of compensating coloring and the function of ensuring the brightness when the liquid crystal panel 100 is observed from the vertical direction of the liquid crystal panel 100. This reduces the number of films as compared to the case where different films must be prepared to perform the respective functions . Consequently, the coloring can be compensated at a low cost.

In view of such low-cost compensation, a polarized light conversion element for increasing the polarized light entering the liquid crystal panel 100 can be utilized as the optical film 81. For example, when DBEF as the polarized light conversion element fabricated by Sumitomo Chemical Industry (Corp.) is employed as the optical film 81, the optical film 81 is capable of causing the optical anisotropy in the plane and generating coloring depending on the observation direction as well as increasing the polarized light entering the liquid crystal panel 100. Consequently, the coloring can be compensated at a low cost. [Fifth Embodiment] In a fifth embodiment, there are embodied a liquid crystal television and a liquid crystal monitor capable of ensuring the sufficient brightness at the observation angle other than 0 degree in the horizontal direction of the liquid crystal panel.

Fig. 26 is a block diagram showing a configuration of the liquid crystal television according to this embodiment. As shown in Fig. 25, a liquid crystal television B comprises the liquid crystal display A described with reference to Fig. 9, and a tuner 26 for selecting a channel of a television broadcast signal input externally. A television video signal of the channel selected by the tuner 26 is input to the controller 22 of the liquid crystal display A as the image signal.

With such a configuration, when the user observes the liquid crystal panel 100 from the observation angle other than 0 degree in the horizontal direction of the liquid crystal panel 100, the sufficient brightness can be obtained. Consequently, the liquid crystal display capable of preferable display is realized.

Fig. 27 is a block diagram showing a structure of the liquid crystal monitor according to this embodiment. As shown in Fig.27, the liquid crystal monitor C comprises the liquid crystal display described above with reference to Fig. 9, and a signal processing portion 27 for processing a monitor signal input externally such as from a personal computer (PC) 28. The monitor image signal processed by the signal processing portion 27 is input to the controller 22 of the liquid crystal display A as the image signal 25.

With such a configuration, when the user observes the liquid crystal panel 100 from the observation angle other than 0 degree in the horizontal direction of the liquid crystal panel 100, the sufficient brightness is given to the user. Therefore, the liquid crystal monitor capable of performing preferable display is achieved. In recent years, in many cases, the moving picture is displayed on the liquid crystal monitor. In such cases , a plurality of users might observe the liquid crystal monitor simultaneously. In such cases, the sufficient brightness can be ensured at the observation angle other than 0 degree in the horizontal direction of the liquid crystal panel 100 to give preferable display to each of the plurality of users.

Numerous modifications and alternative embodiments of the invention will be apparent to those skilled in the art in view of the foregoing description. Accordingly, the description is to be construed as illustrative only, and is provided for the purpose of teaching those killed in the art the best mode of carrying out the invention. The details of the structure and/or function maybe varied substantially without departing from the spirit of the invention and all modifications which come within the scope of the appended claims are reserved.

Industrial Applicability A liquid crystal television of the present invention is useful as a liquid crystal television observed by a plurality of users simultaneously.

A liquid crystal monitor of the present invention is useful as a liquid crystal monitor observed by a plurality of users simultaneously.

A liquid crystal display of the present invention is useful as a liquid crystal display for a liquid crystal television and a liquid crystal monitor observed by a plurality of users simultaneously.

A retardation film of the present invention is useful as a retardation film for improvement of an observation angle characteristic of retardation of a liquid crystal display.

An optical film of the present invention is useful as an optical film for improvement of coloring of a liquid crystal display.

Claims

CLAIMS 1. A liquid crystal display comprising a liquid crystal panel including a liquid crystal layer having arranged liquid crystal molecules and sandwiched between two opposite substrates; and a drive means that changes transmittance of the liquid crystal panel according to an image signal, characterized in that the liquid crystal panel is configured such that transmittance at an inclination angle other than 0 degree is the largest in a transmittance distribution indicating change in transmittance with respect to change in an inclination angle with respect to a normal line of the liquid crystal panel in a predetermined direction of the liquid crystal panel when performing white display.

2. The liquid crystal display according to Claim 1, wherein the liquid crystal panel is configured such that inclination angles with the largest transmittance are present substantially symmetrically with respect to zero degree.

3. The liquid crystal display according to Claim 1, wherein the predetermined direction of the liquid crystal panel is a horizontal direction of the liquid crystal panel of the liquid crystal display being used.

4. A liquid crystal display comprising a liquid crystal panel including a liquid crystal layer having arranged liquid crystal molecules and sandwiched between two opposite substrates; and a drive means that changes transmittance of the liquid crystal panel according to an image signal, characterized in that in the liquid crystal panel included in the liquid crystal display being used and performing white display, when comparison is made between a transmittance distribution indicating change in transmittance with respect to change in an inclination angle with respect to a normal line of the liquid crystal panel in a horizontal direction of the liquid crystal panel and a transmittance distribution indicating change in transmittance with respect to the inclination angle with respect to the normal line of the liquid crystal panel in a vertical direction of the liquid crystal panel, the transmittance of the transmittance distribution in horizontal direction is greater than the transmittance of the transmittance distribution in the vertical direction, over the whole region.

5. A liquid crystal television comprising: a liquid crystal display according to Claim 4; and a tuner portion for selecting a channel of a television broadcast signal, characterized in that the television broadcast signal of the channel selected by the tuner portion is input to the drive means as the image signal.

6. A liquid crystal monitor comprising: a liquid crystal display according to Claim 4; and a signal processing portion for processing a monitor signal, characterized in that a monitor image signal output from the signal processing portion is input to the drive means of the liquid crystal display as the image signal.

7. The liquid crystal display according to Claim 4, wherein directions of rubbing treatment performed on the two substrates to orient the liquid crystal molecules are parallel with each other.

8. The liquid crystal display according to Claim 4, wherein the liquid crystal molecules are bend-oriented.

9. The liquid crystal display according to Claim 8, wherein a direction in which the liquid crystal molecules are oriented is the vertical direction of the liquid crystal panel of the liquid crystal display being used.

10. The liquid crystal display according to Claim 8, further comprising: a polarizer having an absorption axis of 45 degrees with respect to the vertical direction of the liquid crystal panel of the liquid crystal display being used; and a retardation film having an anisotropic axis orthogonal to the direction in which the liquid crystal molecules are oriented.

11. The liquid crystal display according to Claim 4, further comprising: ameans for condensing light toward the normal direction of the liquid crystal panel.

12 The liquid crystal display according to Claim 4, wherein the liquid crystal panel comprises a symmetrization means that substantially symmetrizes the transmittance distribution in the predetermined direction of the liquid crystal panel in black display with respect to the inclination angle of 0 degree.

13. The liquid crystal display according to Claim 12, wherein the liquid crystal panel comprises: a polarizer, and wherein the symmetrization means includes a retardation filmhaving a positive component and placed so that an anisotorpic axis thereof is parallel to an absorption axis or a transparency axis of the polarizer.

14. The liquid crystal display according to Claim 4, further comprising: a lighting device including a light guide plate having an end surface from which light enter and a main surface from which the light emanate, and a light source provided along the end surface of the light guide plate for entering light to the end surface, wherein the light guide plate has an intensity distribution indicating change in light intensity with respect to change in a position of the main surface in a plane of the main surface.

15. The liquid crystal display according to Claim 14, wherein the light intensity distribution is configured to have light intensity decreasing from a central portion of the main surface to a peripheral portion thereof.

16. The liquid crystal display according to Claim 4, further comprising: a lighting device including a light guide plate having an end surface from which light enter and a main surface from which the light emanate, and a light source provided along the end surface of the light guide plate for entering the light to the end surface, wherein the light guide plate is adapted to emanate the light toward the horizontal direction of the liquid crystal panel of the liquid crystal display being used more than the light toward the vertical direction of the liquid crystal panel of the liquid crystal display being used.

17. A liquid crystal display comprising a liquid crystal panel including a liquid crystal layer having arranged liquid crystal molecules and sandwiched between two opposite substrates; and a drive means that changes transmittance of the liquid crystal panel according to an image signal, characterized in that the liquid crystal molecules are bend-oriented, and in the liquid crystal panel included in the liquid crystal display being used and performing white display, a luminance distribution indicating change in luminance with respect to change in an inclination angle with respect to a normal direction of the liquid crystal panel in a horizontal direction of the liquid crystal panel is substantially equal to a luminance distribution indicating change in luminance with respect to change in an inclination angle with respect to the normal direction in a vertical direction of the liquid crystal panel.

18. The liquid crystal display according to Claim 4, wherein the liquid crystal panel has color pixels of respective plural colors and thicknesses of the liquid crystal layer of the color pixels differ according to the colors of the respective color pixels.

19. The liquid crystal display according to Claim 4, wherein the liquid crystal panel comprises at least a retardation film including a negative retardation film.

20. The liquid crystal panel according to Claim 19, wherein retardation in an in-plane direction of the negative retardation film is 100 nm to 240 nm.

21. The liquid crystal display according to Claim 19, wherein the liquid crystal panel is configured so that sum of retardation of the liquid crystal layer and retardation of the retardation film is 260 nm or less when performing white display.

22. The liquid crystal display according to Claim 19, wherein the liquid crystal panel is configured so that sum of retardation of the liquid crystal layer and retardation of the retardation film is 245 nm or less when performing white display.

23. The liquid crystal display according to Claim 19, wherein the liquid crystal panel is configured so that sum of retardation of the liquid crystal layer and retardation of the retardation film is 235 nm or less when performing white display.

24. The liquid crystal display according to Claim 4, wherein the liquid crystal panel is configured so that difference between retardation of the liquid crystal layer in white display and retardation of the liquid crystal layer in black display is 260 nm or less.

25. The liquid crystal display according to Claim 4, wherein the liquid crystal panel is configured so that difference between retardation of the liquid crystal layer in white display and retardation of the liquid crystal layer in black display is 245 nm or less.

26. The liquid crystal display according to Claim 4, wherein the liquid crystal panel is configured so that dif erence between retardation of the liquid crystal layer in white display and retardation of the liquid crystal layer in black display is 235 nm or less.

27. The liquid crystal display according to Claim 4, wherein the liquid crystal panel is configured so that a modulation rate of the liquid crystal layer at the inclination angle of 0 degree is 95% or less.

28. The liquid crystal display according to Claim 4, wherein the liquid crystal panel is configured so that a modulation rate of the liquid crystal layer at the inclination angle of 0 degree is 90% or less.

29. The liquid crystal display according to Claim 4, wherein the liquid crystal panel is configured so that a modulation rate of the liquid crystal layer at the inclination angle of 0 degree is 85% or less.

30. The liquid crystal display according to Claim 1, wherein the liquid crystal panel is configured so that the inclination angle with the largest transmittance in the transmittance distribution is 30 degrees or more.

31. The liquid crystal display according to Claim 1, wherein the liquid crystal panel is configured so that the inclination angle with the largest transmittance in the transmittance distribution is 45 degrees or more.

32. The liquid crystal display according to Claim 1, wherein the liquid crystal panel is configured so that the inclination angle with the largest transmittance in the transmittance distribution is 60 degrees or more.

33. The liquid crystal display according to Claim 1, wherein the liquid crystal panel is configured so that the inclination angle with the largest transmittance in the transmittance distribution is 30 degrees to 60 degrees.

34. The liquid crystal display according to Claim 1, wherein the liquid crystal panel is configured so that difference between the largest transmittance of the transmittance distribution and the transmittance at the inclination angle of 0 degree is 5% or more.

35. The liquid crystal display according to Claim 1, wherein the liquid crystal panel is configured so that difference between the largest transmittance of the transmittance distribution and the transmittance at the inclination angle of 0 degree is 10% or more.

36. The liquid crystal display according to Claim 1, wherein the liquid crystal panel is configured so that difference between the largest transmittance of the transmittance distribution and the transmittance at the inclination angle of 0 degree is 15% or more.

37. A liquid crystal display comprising a liquid crystal panel including a liquid crystal layer having arranged liquid crystal molecules and sandwiched between two opposite substrates; and a drive means that changes transmittance of the liquid crystal panel by applying a voltage to the liquid crystal layer according to an image signal, and characterized in that the liquid crystal panel comprises a retardation film including a negative retardation film. the liquid crystal layer has retardation that decreases from a largest value as the voltage being applied increases, the liquid crystal molecules have parallel orientation and are configured to have bend orientation during display, and the voltage being applied for white display is set to a value lower than a voltage value corresponding to the retardation of the liquid crystal layer with the transmittance of the liquid crystal panel having a peak.

38. The liquid crystal display according to Claim 37, wherein the retardation of the liquid crystal panel decreases as an inclination angle with respect to a normal line of the liquid crystal panel in a direction in which the liquid crystal molecules are oriented increases and the retardation of the liquid crystal panel increases as the inclination angle in a direction perpendicular to the direction in which the liquid crystal molecules are oriented increases .

39. The liquid crystal display according to Claim 38, wherein retardation of the retardation film is set so that the retardation of the liquid crystal panel remains substantially unchanged if there is a change in the inclination angle with respect to the normal line of the liquid crystal panel in the direction in which the liquid crystal molecules are oriented and in the direction perpendicular to the direction in which the liquid crystal molecules are oriented, at a voltage higher than the voltage applied for white display.

40. The liquid crystal display according to Claim 37 , wherein the transmittance at the inclination angle other than 0 degree is the largest in a transmittance distribution indicating change in the transmittance with respect to change in the inclination angle with respect to the normal line of the liquid crystal display in the direction perpendicular to the direction in which the liquid crystal molecules are oriented.

41. The liquid crystal display according to Claim 40, wherein the direction perpendicular to the direction in which the liquid crystal molecules are oriented is a horizontal direction of the liquid crystal panel of the liquid crystal display being used.

42. The liquid crystal display according to Claim 37, wherein the liquid crystal molecules are bar-shaped.

43. The liquid crystal display according to Claim 37, wherein the negative retardation film is constituted by discotheque liquid crystal molecules.

44. The liquid crystal display according to Claim 37, wherein the liquid crystal panel comprises two polarizers between which the two opposite substrates are sandwiched, and amount of light passing through a region between the two polarizers changes as the retardation of the liquid crystal layer changes , thereby causing the transmittance of the liquid crystal panel to change so as to have a peak.

45. The liquid crystal display according to Claim 37, wherein difference between a largest value of the retardation and a value for the retardation of the liquid crystal panel occurring when the voltage for white display is applied is 40 nm or less.

46. The liquid crystal display according to Claim 45, wherein the difference is 30 nm or less .

47. The liquid crystal display according to Claim 45, wherein the difference is 15 nm or less .

48. A retardation film used in a liquid crystal panel included in a liquid crystal display and adapted not to generate retardation when the liquid crystal panel is observed from a direction in which an inclination angle with respect to a normal line of the liquid crystal panel is 0 degree, characterized in that the retardation film is adapted to generate the retardation when the liquid crystal panel is observed from the inclination angle other than 0 degree in a vertical direction of the liquid crystal panel of the liquid crystal display being used, and adapted not to generate the retardation when the liquid crystal panel is observed from the inclination angle other than 0 degree in a horizontal direction of the liquid crystal panel of the liquid crystal display being used.

49. The liquid crystal display according to Claim 4, the liquid crystal panel comprises a retardation film according to Claim 48.

50. An optical film used in a liquid crystal panel included in a liquid crystal display, characterized in that the optical film is adapted not to generate coloring when the liquid crystal panel is observed from a direction in which an inclination angle with respect to a normal line of the optical film is 0 degree and adapted to generate coloring when the liquid crystal panel is observed from a direction in which the inclination angle is other than 0 degree.

51. The optical film according to Claim 50, adapted to change the coloring according to the inclination angle.

52. The optical film according to Claim 50, having a mechanism for generating interference of light.

53. The optical film according to Claim 50, having a mechanism for generating diffraction of light.

54. The optical film according to Claim 50, having a mechanism for generating refraction of light.

55. The liquid crystal display according to Claim 4, wherein the liquid crystal panel comprises an optical film according to Claim 42.

56. The optical film according to Claim 50, adapted to condense light toward the direction in which the inclination angle is 0 degree.

57. The liquid crystal display according to Claim 55, wherein the optical film is adapted to condense light toward a normal direction of the liquid crystal panel.

58. The optical film according to Claim 50, adapted to increase polarized light entered to the liquid crystal panel.

59. The optical film according to Claim 52 , wherein the mechanism for generating the interference of light is constituted by a multi-layered film provided on a main surface of the optical film.

60. The optical film according to Claim 52 , wherein the mechanism for generating the interference of light is constituted by a cholesteric liquid crystal provided on the main surface of the optical film.

61. The optical film according to Claim 53 , wherein the mechanism for generating the diffraction of light is constituted by a plurality of members having refractive indices different from a refractive index of the optical films provided in stripe in the main surface of the optical film.

62. The optical film according to Claim 53, wherein the mechanism for generating the diffraction of light is constituted by a plurality of grooves provided in stripe in the main surface of the optical film.

63. The optical film according to Claim 54, wherein the mechanism for generating the refraction of light is constituted by a prism sheet bonded to the main surface of the optical film.

64. The optical film according to Claim 52, wherein the mechanism for generating the interference of light is constituted by an interference film bonded to the main surface of the optical film, and the interference film has a cross section causing optical anisotropy in a plane of the optical film.

65. A liquid crystal display comprising a liquid crystal panel including a liquid crystal layer having arranged liquid crystal molecules and sandwiched between two opposite substrates; and a drive means that changes transmittance of the liquid crystal panel according to an image signal, characterized in that the liquid crystal panel is configured such that transmittance distribution indicating change in transmittance with respect to change in an inclination angle with respect to a normal line of the liquid crystal panel in a horizontal direction of the liquid crystal panel is substantially trapezium shaped when performing white display.

66. A liquid crystal television comprising a liquid crystal display according to Claim 65 and a tuner portion for selecting a channel of a television broadcast signal, characterized in that a television video signal of the channel selected by the tuner portion is input to drive means of the liquid crystal display as an image signal.

67. A liquid crystal monitor comprising a liquid crystal display according to Claim 65 and a signal processing portion for processing a monitor signal, characterized in that a monitor video signal output from the signal processing portion is input to drive means of the liquid crystal display as an image signal.