CN100523963C - Display apparatus having reflective layer - Google Patents
Display apparatus having reflective layer Download PDFInfo
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- CN100523963C CN100523963C CNB200510080737XA CN200510080737A CN100523963C CN 100523963 C CN100523963 C CN 100523963C CN B200510080737X A CNB200510080737X A CN B200510080737XA CN 200510080737 A CN200510080737 A CN 200510080737A CN 100523963 C CN100523963 C CN 100523963C
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Abstract
The present invention provide a display device with a reflecting layer, which is characterized in: a reflecting layer is formed on a first substrate, and the reflecting layer is insulated from a switching element on the insulation film of the switching element arranged in each pixel, and reflect the incident light from the side of a second substrate through a second electrode formed with ITO; a first electrode made of a transparent conducting material (i.e., ITO) with the same function as the second electrode is formed at a position that is closer to the liquid crystal layer than the reflecting layer, and the first electrode is connected to the switching element. The film thickness of the first electrode is smaller than 100 micro meters or between 750 and 1250 micro meters. In that way, not only inhomogeneous color or reduced reflectivity caused by the first electrode can be prevented, but also the liquid crystal layer can be driven by alternating current with the first electrode and the second electrode in good symmetry. In addition, alternatively, the switching element can be connected to the reflecting electrode, and the first electrode with an insulating film can be coupled to the reflecting electrode through capacitance, and then the first electrode can be driven by the reflecting electrode through the capacitance.
Description
The application be the applying date is 2003-3-4, for application number 03107054.X, application people be dividing an application of " display device " for Sanyo Electric Co., Ltd, denomination of invention with reflection horizon.
Technical field
The present invention relates to a kind of the possess reflection-type of reflection function or the liquid crystal indicator of semi-transmission type.
Background technology
Liquid crystal indicator (below be referred to as LCD) possesses the feature that volume is little and power consumption power is low, at present, is used in widely on the display of graphoscope, portable information machine etc.Above-mentioned LCD, between a pair of substrate, enclose liquid crystal, and by the electrode control bit that is formed at each substrate therebetween liquid crystal aligning and show, be different from that CRT (leonard's tube) shows, electroluminescence (following, be referred to as EL) shows etc., because of can't be luminous voluntarily on the principle, so need possess light source during to observer's show image.
Therefore, infiltration type LCD adopts transparency electrode as the electrode that is formed at each substrate, at the rear or the side configuration light source of display panels, and controls the transit dose of this light source light by liquid crystal panel, whereby, even under dim environment, also can know demonstration.Yet, because infiltration type LCD need put bright light source for a long time showing, thereby have: can't avoid the power consumption that causes because of light source, and, can't guarantee fully to contrast characteristics showed as daytime outdoor, under the quite strong environment of light.
On the other hand, reflection type LCD adopts outer light such as the sun, room lighting as its light source, and by the reflecting electrode of the substrate that is formed at non-observer's side, reflection is incident in the above-mentioned light source on every side of liquid crystal panel.Then, according to each pixel, control is incident in liquid crystal layer and shows via the emitted light quantity of the liquid crystal panel of the light that reflecting electrode reflected.Above-mentioned reflection type LCD, owing to adopt outer light as light source, therefore outside lacking, promptly can't show under the situation of light, but be different from infiltration type LCD, it there is no the power consumption that causes because of light source is the extremely low LCD of a kind of power consumption power, in addition, also can obtaining fully under the very bright state of environment around the outdoor grade, contrast shows.Yet this reflection type LCD has always: on general display quality such as the reappearance of color and display brightness all than the inadequate problem of the LCD of infiltration type.
On the other hand, under the situation of the power consumption that requires to reduce more machine, compared to infiltration type LCD, the reflection type LCD with low consumption electric power is comparatively favourable, so attempt it is used on the high meticulous demonstration purposes etc. of portable machine, and promote the research and development of display quality.
Fig. 1 is shown in possess thin film transistor (TFT) in each pixel planar configuration (the 1st substrate-side) of 1 pixel of reflection type LCD of traditional active-matrix type of (TFT:Thin film Transistor), and Fig. 2 shows the summary profile construction of the reflection type LCD of the C-C line that is positioned at Fig. 1.
200 of the 1st substrate 100 that reflection type LCD is fitted at the interval preset distance and the 2nd substrates are enclosed liquid crystal layer 300 and are constituted.1st, the 2nd substrate 100,200 adopts glass substrate or plastic base etc., and at least in the present embodiment, the 2nd substrate 200 that is disposed at the sightingpiston side adopts transparency carrier.
On the face of the liquid crystal side of the 1st substrate 100, form TFT110 according to each pixel.The for example drain region of the active layer 120 of this TFT110, across the contact hole that is formed at interlayer dielectric 134, and be connected with in order to data-signal is supplied to the data line 136 of each pixel, the contact hole that the source region then forms by connecting interlayer dielectric 134 and planarization insulating film 138, and be connected with the 1st electrode (pixel electrode) 150 that forms indivedual patterns according to each pixel.
Above-mentioned the 1st electrode 150 uses Al, the Ag etc. that possess reflection function, is formed with the oriented film 160 in order to the initial stage orientation of control liquid crystal layer 300 on this reflecting electrode 150.
When display device is colour display device, color filter (R, G, B) 210 corresponding each pixel electrode 150 and be formed at the liquid crystal side of the 2nd substrate 200 that is relative to the configuration with the 1st substrate 100, and on color filter 210, be formed with the transparency electrode 250 of using ITO transparent conductive materials such as (Indium Tin Oxide) and making, with as the 2nd electrode.In addition, on this transparency electrode 250, form the oriented film 260 identical again with the 1st substrate-side.
Reflection type LCD has above-mentioned formation, and is incident in liquid crystal panel and reflects the light quantity that is penetrated by liquid crystal panel again via reflecting electrode 150 according to each pixel control, and carries out desirable demonstration.
Be not limited to reflection type LCD, in LCD, alternating voltage drives the generation of liquid crystal to prevent to burn.And infiltration type LCD, because of the 1st electrode on the 1st substrate and the 2nd electrode on the 2nd substrate need use transparent material, so both all adopt ITO as electrode material.Therefore, when carrying out the AC driving of liquid crystal, the 1st and the 2nd electrode can alternatively put on liquid crystal with positive and negative voltage under roughly the same condition.
Yet, as above-mentioned shown in Figure 2, use by the formed reflecting electrode of metal material as the 1st electrode 150, and use by in the reflection type LCD of the formed transparency electrodes of transparent metal oxidation material such as ITO as the 2nd electrode 250, decide on drive condition, the instability (glimpsing) that produce to show sometimes, or liquid crystal such as burns at problem.This kind problem for example, the shape of healing when driving liquid crystal under the situation that is lower than the critical flicker frequency of being reported recently (CFF) is remarkable.Be lower than the driving of CFF, be meant: for further reaching the low consumption electrification of LCD, and attempt with the driving frequency of liquid crystal (
Be formed at the data write frequency of the liquid crystal that is arranged in each pixel (liquid crystal capacitance) in the subtend zone of the 1st and the 2nd electrode respectively), be set at lower than the 60Hz of institute's benchmarks such as NTSC specification, that is be set to people's vision and can experience below the CFF that glimpses, for example be set between the 40Hz to 30Hz.Yet, with the above-mentioned frequency that is lower than CFF, when driving each pixel of existing reflective liquid crystal panel, can make above-mentioned glimpse and liquid crystal problem such as the burn shape of healing remarkable, and cause the significantly reduction of display quality.
Glimpsing or occurrence cause that liquid crystal burns of relevant Fig. 2, reflection type LCD shown in Figure 3, according to the result of patent applicant's research, this problem is because of in the asymmetry of the electrical character of the 1st electrode and the above-mentioned liquid crystal layer 300 of the 2nd electrode pair.This asymmetry results from: the work function (work function) that is used in the transparent metal oxides such as ITO of the 2nd electrode 250 is the degree of 4.7eV to 5.2eV, and the work function that is used in the metals such as AL of the 1st electrode 150 is about the degree of 4.2eV to 4.3eV, the excessive event of difference between the two.The difference of work function can make actual see through oriented film 160,260 and lure the charge generation difference that arises from liquid crystal interface when same voltage is put on each electrode.In addition, by the difference that lures the electric charge that arises from above-mentioned liquid crystal aligning membrane interface, the secund electrode sides of meeting such as the foreign ion in the liquid crystal layer, its result causes residual DC voltage to be accumulated in liquid crystal layer 300.The driving frequency of liquid crystal is lower, and this residual DC is then bigger to the influence of liquid crystal, and glimpse, also more shape is remarkable for problem that liquid crystal burns, therefore, the driving that particularly is lower than CFF has its substantial difficulty.
In addition, reflection type LCD of the prior art still has: use ITO in the 1st and the 2nd electrode as infiltration type LCD, and the formation of reflecting plate is set in addition in the outside (the non-subtend of liquid crystal) of the 1st substrate.Yet when the arranged outside reflecting plate of the 1st substrate, optical path length only extends the thickness of transparent the 1st electrode 150 and transparent the 1st substrate, therefore causes the reduction of display quality easily.Therefore, require the reflection type LCD of the demonstration purposes of high display quality, use reflecting electrode, as mentioned above, cross when driving frequency and can produce the problem that glimpses when low, therefore, just can't reduce driving frequency for reaching the purpose of low consumption electrification as pixel electrode.
Summary of the invention
The object of the present invention is to provide a kind of liquid crystal indicator, have the electric characteristics of the 1st and the 2nd electrode of corresponding liquid crystal layer, can eliminate glimpsing or parallax effects, reduce problems such as irregular colour, and realize high-quality demonstration and low consumption electrification.
In order to realize purpose of the present invention, the invention provides a kind of liquid crystal indicator, wherein, according to each pixel, in the 1st substrate that possesses the 1st electrode and possess and enclose liquid crystal layer between the 2nd substrate of the 2nd electrode and constitute, with the liquid crystal indicator of the demonstration of carrying out each pixel, described the 1st substrate still possesses and has: the on-off element that is disposed at each pixel; And reflecting electrode, part ground covers a pixel region, and electrically connects with this on-off element on on-off element, and will be reflected from the light that described the 2nd substrate is incident in described liquid crystal layer; Forming the transparency electrode that constitutes by transparent conductive material across dielectric film on the described reflecting electrode and between described reflecting electrode, this transparency electrode is to form electric capacity as described the 1st electrode with described reflection horizon to combine, be supplied to the voltage of described reflecting electrode by described on-off element, electric capacity by being constituted in the described reflecting electrode that disposes in the mode of seizing described dielectric film between the two on both sides by the arms and described transparency electrode puts on described transparency electrode.
As mentioned above in the 1st substrate-side, the 1st transparent electrode that has identical characteristics in the 2nd electrode of liquid crystal layer side configuration and the 2nd substrate, and, whereby, can utilize the 1st electrode and the 2nd electrode to drive liquid crystal layer with good symmetry in the lower floor configuration reflection horizon of the 1st electrode.In addition, the work function of the described transparent conductivity material of described the 1st electrode, poor with the work function of the transparent conductivity material of described the 2nd electrode of the liquid crystal layer side that is formed at described the 2nd substrate can be by being set in below the 0.5Ev, and help the good driving of symmetry especially.In addition, by adopting above-mentioned formation, be lower than 60Hz, also can not produce the phenomenon that glimpses and high-quality demonstration is provided even the driving frequency of the liquid crystal layer in each pixel for example set for.In addition, the present invention adopts: by the reflecting electrode that is connected in on-off element, and utilize electric capacity to put on the structure of the 1st transparent electrode in conjunction with the voltage that liquid crystal drive is used.Therefore, though constitute the electrode of the 1st substrate-side by reflecting electrode and transparent the 1st interelectrode multi-ply construction, but be connected structure between on-off element and reflecting electrode, can adopt with pixel electrode in use the roughly the same structure of existing reflection-type liquid-crystal display device of metallic reflection electrode, therefore only with MIN design alteration, can realize the lifting of display quality, and reduce power consumption.
According to other aspects of the invention, in the liquid crystal indicator of the present invention, in each pixel, possess the 1st substrate that the 1st electrode is arranged and possess and enclose liquid crystal layer between the 2nd substrate of the 2nd electrode and constitute, with the liquid crystal indicator of the demonstration of carrying out each pixel, described the 1st substrate still possesses and has: the on-off element that is disposed at each pixel; On described on-off element, electrically connect with this on-off element, and the reflecting electrode that will be reflected from the light that described the 2nd substrate-side is incident in described liquid crystal layer; On described reflecting electrode, and form the transparency electrode that constitutes by transparent conductive material across dielectric film between described reflecting electrode, this transparency electrode is to form electric capacity as described the 1st electrode with described reflecting electrode to combine, be supplied to the voltage of described reflecting electrode by described on-off element, by the electric capacity that is constituted between described reflecting electrode that disposes in the mode of seizing described dielectric film between the two on both sides by the arms and the described transparency electrode, and put on described transparency electrode, therebetween seize described liquid crystal layer on both sides by the arms and described the 1st electrode of subtend configuration and the capacitance C1 of the pixel capacitance that described the 2nd electrode is constituted, the capacitance C2 of the electric capacity that is constituted with described reflecting electrode and described the 1st electrode meets
C2>100×C1
Relational expression.
According to other aspects of the invention, in the liquid crystal indicator of the present invention, in each pixel, possess the 1st substrate that the 1st electrode is arranged and possess and enclose liquid crystal layer between the 2nd substrate of the 2nd electrode and constitute, with the liquid crystal indicator of the demonstration of carrying out each pixel, described the 1st substrate still possesses and has: the on-off element that is disposed at each pixel; Reflecting electrode electrically connects with this on-off element on described on-off element, and will be reflected from the light that described the 2nd substrate is incident in described liquid crystal layer; On described reflecting electrode, and form the transparency electrode that constitutes by transparent conductive material across dielectric film between described reflecting electrode, this transparency electrode is to form electric capacity as described the 1st electrode with described reflection horizon to combine, be supplied to the voltage in described reflection horizon by described on-off element, put on described transparency electrode by described electric capacity combination, therebetween seize described liquid crystal layer on both sides by the arms and with the area C1 of described 1st electrode of described the 2nd electrode pair to configuration, the described reflecting electrode of subtend configuration and the overlapping area S2 of described the 1st electrode meet with therebetween seizing described liquid crystal layer on both sides by the arms
S2>0.1×S1
Relational expression.
When on formed reflection substrate, forming transparent conductive material by metal material, because of on this reflecting electrode surface, be formed with natural oxide film so, make reflecting electrode and transparent the 1st electrode formation state of insulation.But by capacitance, area design are become can meet the above-mentioned relation formula, can make the reflecting electrode that is connected in on-off element, be able in the 1st transparent electrode, apply the voltage that is enough to drive liquid crystal by the electric capacity combination.
According to other aspects of the invention, in above-mentioned liquid crystal indicator, the thickness of the transparency electrode that combines with above-mentioned reflecting electrode formation electric capacity can be set in 750
To 1250
Scope, or 1
To 100
Scope.
By being set at above-mentioned thickness, can realize not having the high-quality demonstration of irregular colour.
Luminous display unit according to other aspects of the invention, be formed at the interarea side of substrate, and has light-emitting component, this light-emitting component possesses the 1st electrode, light emitting element layer and the 2nd electrode, on described substrate, be formed with in order to reflection by the reflection of light layer of described light emitting element layer or the incident of described the 2nd electrode side institute with as the 1st electrode, by transparent conductive material constitute and thickness 1
To 100
Scope in transparency electrode, cover described reflection horizon and form, between described reflection horizon and described substrate, according to each pixel on-off element is set again, this on-off element is connected with described reflection horizon, interlayer in described reflection horizon and described transparency electrode forms dielectric film, described transparency electrode sees through this dielectric film and combines with described reflection horizon formation electric capacity, supplying to the voltage in described reflection horizon by described on-off element, is the electric capacity that is constituted between the described reflecting electrode that disposes by seizing described dielectric film on both sides by the arms and the described transparency electrode and put on described transparency electrode.
As mentioned above, in luminous display unit, in the formation that possesses reflection horizon that the substrate-side of being stacked on is arranged and transparency electrode, be set in 750 by thickness with transparency electrode
To 1250
Scope in, or be set in 1
To 100
Scope, can avoid being subjected to penetrating the irregular colour of the light of element top after the reflective layer reflects, and carry out high-quality demonstration.
Description of drawings
Fig. 1 is the part planar configuration figure of the 1st substrate-side of the reflection type LCD of active-matrix type of the prior art.
Fig. 2 is the summary sectional structural map of reflection type LCD of the prior art that is positioned at the C-C line of Fig. 1.
Fig. 3 is the summary planar configuration figure of the 1st substrate-side of reflection type LCD of the active-matrix type of the 1st embodiment of the present invention.
Fig. 4 is the summary sectional structural map of reflection type LCD that is positioned at the A-A line of Fig. 2.
Fig. 5 is the legend of the wavelength interdependence of the reflectivity of each thickness of showing the 1st electrode be arranged in the 1st embodiment of the present invention.
Fig. 6 is the legend of the coordinate on the XYZ chromaticity diagram of each thickness of the 1st electrode of demonstration the 1st embodiment of the present invention.
Fig. 7 is the summary planar configuration figure of the 1st substrate-side of the semi-transmission type LCD of the active-matrix type of demonstration the 1st embodiment of the present invention.
Fig. 8 is the summary sectional structural map that shows the semi-transmission type LCD of the B-B line that is positioned at Fig. 7.
The summary sectional structural map that Fig. 9 shows for the organic EL that shows active-matrix type of the present invention.
Figure 10 is the summary planar configuration figure of the 1st substrate-side of the reflection type LCD of the active-matrix type of demonstration the 2nd embodiment of the present invention.
Figure 11 is the summary sectional structural map that shows the reflection type LCD of the A-A line that is positioned at Figure 10.
Figure 12 is the equivalent circuit diagram of 1 pixel of demonstration the 2nd embodiment of the present invention.
Figure 13 is the summary planar configuration figure of the 1st substrate-side of the semi-transmission type LCD of the active-matrix type of demonstration the 2nd embodiment of the present invention.
20 active layer 20c passage area
20s source region, 20d drain region
30 gate insulating films, 34 interlayer dielectrics
36 drain electrodes, 38,39 planarization insulating films
40 source electrodes, 42 metal levels
44 reflection horizon (reflecting electrode)
46 natural oxide films (natural dielectric film)
50 the 1st electrodes, 60 oriented films
80 anodes, 82 positive hole transfer layer
83 luminescent layers, 84 electron supplying layers
86 negative electrodes, 88 organic element layers
90 organic ELs 100 the 1st substrate
110 TFT, 120 active layers
134 interlayer dielectrics, 136 data lines
138 planarization insulating films 150 the 1st electrode
160,260 oriented films 200 the 2nd substrate
210 color filters 250 the 2nd electrodes (transparency electrode)
300 liquid crystal layers
Embodiment
Below, with reference to accompanying drawing, most preferred embodiment of the present invention (hereinafter referred to as embodiment) is described.
Fig. 3 shows the some as the planar configuration of the 1st substrate-side of the reflection-type active-matrix type LCD of the reflection type LCD of the 1st embodiment, and Fig. 4 then shows, is positioned at the summary profile construction of LCD of the A-A line of Fig. 3.According to active-matrix type LCD, in the viewing area, a plurality of pixels are set, and on-off elements such as TFT are set in each pixel with rectangular.On-off element is formed at a side of the 1st and the 2nd substrate, the 1st substrate 100 sides for example according to each pixel, and the pixel electrode (the 1st electrode) 50 that forms indivedual patterns is connected in this on-off element.
The the 1st and the 2nd substrate 100,200, use transparency carriers such as glass, relative with the 1st substrate to the 2nd substrate 200 sides, ground same as the prior art, under the situation of color-type, respective pixel electrode 50 and form color filter 210 then forms the 2nd electrode 250 that is made of transparent conductive material on this color filter 210.The transparent conductive material of the 2nd electrode 250 adopts IZO (Indium Zinc Oxide) or ITO etc.In addition, during for the active-matrix type, the 2nd electrode 250 forms the common electrode of corresponding each pixel.In addition, on this kind the 2nd electrode 250, then be formed with by the formed oriented film 260 of polyimide.
For the 2nd substrate-side of above-mentioned formation, in the present embodiment, adopt the electrode structure of the electric characteristics of the liquid crystal layer 300 that possesses corresponding the 1st substrate-side.Particularly, as shown in Figure 4, under the oriented film on the 1st substrate 100, formation is not the reflective metals electrode that formation was adopted in the past by the 1st electrode 50 that transparent conductive material constituted identical with the 2nd electrode 250 such as work function and the 2nd electrode 250 materials similar that is IZO, ITO etc.In addition, for making reflection type LCD, and form in order to the reflection of incident light layer 44 of reflection from the 2nd substrate-side in the lower floor of the 1st electrode 50.
The 1st electrode 50 employed materials, by adopting and the 2nd electrode 250 identical materials, and the electrode that makes the same work function of tool is able to therebetween be disposed at liquid crystal layer 300 across oriented film 60,260, therefore, can be by the 1st electrode 50 and the 2nd electrode 250, AC driving liquid crystal layer 300 under the suitable good state of symmetry.But, even the work function of the 1st electrode 50 and the 2nd electrode 250 and not quite identical, as long as both are approximate to the degree that can drive liquid crystal layer 300 under the symmetry kilter.For example, the work function of two electrodes is set in 0.5Ev when following, even the driving frequency of liquid crystal is lower than above-mentioned CFF, also can avoids glimmering or liquid crystal such as burns at the generation of problem, and realize high-quality demonstration.
As the 1st electrode 50 that meets above-mentioned condition and the 2nd electrode 250, for example, can on the 1st electrode 50, use IZO (work function 4.7eV to 5.2eV), and on the 2nd electrode 250, use ITO (work function 4.7eV to 5.0eV), or both vice versas, when selecting material,, also can select to be used in the material of each electrode respectively for considering characteristic on the processing procedures such as transmitance, pattern precision, and manufacturing cost etc.
As mentioned above, reflection horizon 44 is made of conductive materials such as Al-Nd alloys, and the 1st electrode 50 and reflection horizon 44 formation that are stacked on this reflection horizon 44 are electrically insulated.The reason of insulation is: when adopting IZO, ITO etc. as the material of the 1st electrode 50, both by sputter and film forming so.That is,, make its surface produce oxidation reaction, and covered by being exposed in the sputter environment by formed reflection horizon 44 such as Al by natural oxide film.Therefore, in the present embodiment, use as the 1st electrode that drives liquid crystal in this reflection horizon 44 and unlike reflection type LCD of the prior art, but be used as the use of the 1st electrode with the transparency conducting layer that is formed on the reflection horizon 44, and cooperate displaying contents that liquid crystal layer 300 is applied voltage.
According to above-mentioned formation, in present embodiment 1, the thickness of above-mentioned transparent the 1st electrode 50 is at (a)
Below, particularly exist
Extremely
Scope in, and preferably between
Extremely
Scope.Or (b)
Extremely
Scope, for example
About.Even adopt transparent materials such as IZO, ITO, its light transmission rate is not 100% yet, can be subjected to the influence of wavelength dependency in addition yet.Particularly, as the reflection type LCD of present embodiment, owing to reflection horizon 44, penetrate by the 2nd substrate-side again after the reflection by liquid crystal layer 300 from the light of the 2nd substrate-side incident, so light passes through the 1st electrode 2 times.Therefore, if do not consider the optical characteristics of the 1st electrode 50, will make that the influences such as reduction of irregular colour, transmitance are more obvious.But, be set in above-mentioned (a) or the scope (b) by thickness the 1st electrode 50, can avoid the reduction of irregular colour or transmitance.In addition, when the 1st electrode 50 is made above-mentioned thickness, preferably will be set in by the thickness of the formed counter electrode 250 of identical transparent electrode material
Extremely
Degree (for example be set in
).In addition, under present embodiment, the thickness in reflection horizon 44 is set at
Extremely
Degree (for example
About).
Fig. 5 is presented at the upper strata in reflection horizon 44, the wavelength dependency of the reflectivity when forming by formed the 1st electrode 50 of the different IZO of thickness d.In Fig. 5, transverse axis is that incident wavelength (nm), the longitudinal axis are reflectivity R (%).The thickness d of the 1st electrode 50 is set as:
In addition, reflection horizon 44 used thicknesses are
The Al-Nd alloy.Can know by Fig. 5 and to learn, when
The time, with
The time, that is when not forming the 1st electrode similarly, in the wavelength domain of 400nm to 800nm, reach 100% reflectivity nearly.And work as
And
, the reflectivity in the long zone of all-wave does not reach 100%.In addition, work as d=750
The time, at long wavelength side, its reflectivity is not high, but then can obtain higher reflectivity in the wavelength side that is shorter than 600nm.
Fig. 6 is on the formed reflection horizon 44 by the Al-Nd alloy, the XYZ chromaticity diagram when forming by formed the 1st electrode 50 of the different IZO of thickness d.The thickness d of the 1st electrode 50, identical with above-mentioned Fig. 3, for
Can learn by the 6th figure,
The time, in XYZ chromaticity diagram, be positioned at
The time that is roughly the same coordinate when not forming the 1st electrode 50, and realize Color reproduction identical when not forming the 1st electrode 50.
Under remember table 1
[table 1]
| x | y | Y | |
| d?0(Al—Nd) | 0.313 | 0.330 | 98.8 |
| d?1250(Al-Nd+IZO1250) | 0.322 | 0.349 | 94.8 |
| d?1000(Al-Nd+IZO1000) | 0.307 | 0.330 | 92.6 |
| d?750(Al-Nd+IZO750) | 0.290 | 01312 | 79.0 |
| d?500(Al-Nd+IZO500) | 0.316 | 0.319 | 68.7 |
| d?200(Al-Nd+IZO200) | 0.324 | 0.343 | 88.4 |
| d?100(Al-Nd+IZO100) | 0.315 | 0.331 | 95.8 |
| d?50(Al-Nd+IZO50) | 0.313 | 0.329 | 97.6 |
| d?25(Al-Nd+IZO25) | 0.313 | 0.329 | 98.3 |
| d?12(Al-Nd+IZO12) | 0.313 | 0.330 | 98.8 |
Y＝K∫S(λ).R(λ).y(λ)dλ
The beam split of S (λ) illumination light distributes
The spectral reflectance of R (λ) test portion
Y (λ) isochrome function
λ wavelength (limit of integration is 380nm to 780nm in principle)
The x of each thickness d of the 1st electrode 50 of table 1 displayed map 6, y coordinate figure, and the Y value of each thickness when being d.This Y value is the pointer of reflectivity, and expression is brighter near 100, that is in the present embodiment, does not see the relaxation phenomenon of the 1st electrode 50.In table 1, the Y value during d0 is 98.8, with respect to this, when
In any one the time, can realize up to the Y value more than 90.
The time Y value be 79.0, though more described person is low, also can obtain higher value.
Learn by above-mentioned each measurement result, be formed at the thickness d of the 1st electrode 50 on the reflection horizon 44, be lower than 100 with (a)
Degree, or (b) between
Extremely
Degree the most suitable.In addition, aspect the condition of keeping with the objectivity of the driving of common electrode 250 (a), must greater than
, for example exist
More than, under the reliability of considering processing procedure, preferably be set in
As for condition (b), with greater than
Less than
Ideal, in addition, except optical characteristics,, and consider its resistance based on the viewpoint of the concavo-convex lining of corresponding lower floor, then preferably be set in
About.
Yet, in recent years, the existing motion that possesses the so-called semi-transmission type LCD of light transmission function and reflection function simultaneously, the formation of this semi-transmission type LCD, LCD is identical with infiltration type, forms earlier pixel electrodes such as ITO, and covers the subregion of this transparency electrode and the reflecting electrode of lamination Al etc.This kind semitransparent type LCD is by substrate-side in regular turn behind lamination transparent electrode layer/reflection electrode layer, and 2 electrode layers will produce and electrically connect and bring into play the function of a pixel electrode.But, as above-mentioned, because at liquid crystal side configuration reflecting electrode,, and cause under the symmetry good state, driving the problem of liquid crystal layer 300 therefore based on different with the work function of the 2nd electrode.In addition, for electrical symmetry is promoted, though consider the laminated layer sequence of this electrode is put upside down, but as above-mentioned, be used in the Al of reflecting electrode or the metal material of Ag, its surface is easy to form natural oxide film, particularly after forming above-mentioned metal level, by it is exposed in order in the sputter that forms transparent conductive material layer, the surface is covered by natural oxide film, and make metal level and transparency electrode insulation.Therefore, only change the laminated layer sequence of electrode, the 1st substrate-side can't drive liquid crystal by transparency electrode.
Therefore, in present embodiment 1, by reflection horizon 44 and the 1st electrode 50 and TFT110 are insulated simultaneously, and make to connect and (for example be the 1st electrode 50 and TFT110 with metal level 42 Jie, the source electrode 40 of TFT110) between, and connects the 1st electrode 50 and TFT110.Whereby, identical with the 2nd substrate-side, also can drive liquid crystal in the 1st substrate-side by being formed the 1st electrode 50 of the transparent conductive material that closely connects configuration with liquid crystal layer.
For connecting the 1st electrode 50 and TFT110, above-mentioned metal level 42 necessary conditions that present embodiment adopted are:
(i) remove and electric connection by formed the 1st electrodes 50 such as IZO or ITO,
(ii) as shown in Figure 4,, can electrically connect, or during omission source electrode 40, can electrically connect with semiconductor (is polysilicon at this) active layer with this source electrode 40 if when being provided with the source electrode 40 of Al for example etc. among the TFT110,
(iii) during with reflection horizon 44 patternings, can not removed etc. by the etching solution in this reflection horizon 44 according to the individual shaped of each pixel.
As above-mentioned metal level 42, preferably use refractory metal materials such as Mo, Ti, Cr.
Below, the structure that can connect the 1st electrode 50 and pairing TFT110 really of present embodiment and the manufacture method that realizes this kind structure are described.
Aspect TFT110, adopt the top grid type, in addition, active layer 20 adopts by the polysilicon (p-Si) of annealing laser processing with gained after amorphous silicon (a-Si) multiple crystallization.Certainly, TFT110 is not limited to top grid type p-Si, also can use the bottom gate polar form, or adopts a-Si on active layer.Being doped in the regions and source 20s of the active layer 20 of TFT110, the impurity of 20d, can be arbitrary type of n conductivity type, p conductivity type, but in the present embodiment, n conductive-type impurities such as Doping Phosphorus, and the TFT110 of employing n-ch type.
The active layer 20 of TFT110 is covered by gate insulating film 30, but forms the gate electrode 32 by dual-purpose gate lines that forms such as Cr on gate insulating film 30.Then, after forming gate electrode 32, with this gate electrode above-mentioned impurity that on active layer 20, mixes as shielding, forming source electrode and utmost point polar region territory 20s, 20d, and the passage area 20c of impurity not.Then, cover this TFT110 integral body and form interlayer dielectric 34, after forming contact hole on this interlayer dielectric 34, form electrode material, and by this contact hole, make source electrode 40 be connected in the source region 20s of above-mentioned p-Si active layer respectively, and make drain electrode 36 be connected in drain region 20d.In addition, in the present embodiment, drain electrode 36 double as use for the data line of each TFT110 being supplied with the data-signal of corresponding displaying contents.On the other hand, source electrode 40 is general as described later, is connected with the 1st electrode 50 as pixel electrode.
After source electrode 40 forms with drain electrode 36, whole of covered substrate is to form by formed planarization insulating films 38 of resin material such as acrylic acid (arcylic) resins, formation zone at source electrode 40 forms contact hole, and form connection herein with metal level 42, to connect source electrode 40 and this metal level 42.If use Al etc. as source electrode 40, then can contact and make with the good resistance that is connected to form of 40 of source electrodes by metal materials such as use Mo as metal level 42.In addition, also can omit source electrode 40, at this moment, metal level 42 can contact with the silicon active layer 20 of TFT110, but metals such as Mo can establish with this kind semiconductor between resistance contact.
After finishing the lamination that connects with metal level 42, patterning, constitute material that the Al-Nd alloy in reflection horizon 44 or Al etc. have a good reflection characteristic and be stacked on whole of substrate by evaporation or sputter.Can not hinder the metal level 42 and the mode that contacts of formed the 1st electrode 50 afterwards at least, this reflecting material of institute's lamination is removed in etching, make near its source region that can not remain in TFT110 (the formation zone of metal level 42), and in each pixel, form the reflection horizon 44 of pattern shown in Figure 3.In addition, produce leakage current in order to prevent illumination to be mapped to TFT110 (particularly passage area 20c), simultaneously in order to enlarge reflexible zone (that is viewing area) as far as possible, in the present embodiment, as shown in Figure 3, also actively form reflection horizon 44 at the passage upper area of TFT110.
When carrying out the patterning in this kind reflection horizon 44, by the metal level 42 that above-mentioned Mo etc. forms, possessing has enough thickness (for example 0.2 μ m), and etching is also had sufficient patience.Even therefore after the reflection horizon 44 on etching removal metal level 42, this metal level 42 can not be removed fully yet, and is remained in the contact hole.In addition, as a rule, source electrode 40 grades are because by being constituted with reflection horizon 44 identical materials (Al etc.), and therefore as if there not being above-mentioned metal level 42, then can be reflected layers 44 etching solution of source electrode 40 corrodes and produces problem such as broken string.But by metal level 42 is set, not only anti-in the reflection horizon 44 patterning, can keep excellent electrical property with source electrode 40 simultaneously and contact.
After finishing the patterning in reflection horizon 44, for reaching above-mentioned thickness condition, and make its covering comprise whole of the substrate in reflection horizon 44 by the stacked transparency conducting layer of sputter.At this, as above-mentioned, by the surface in formed reflection horizon 44 such as Al, this moment, the natural oxide film 46 by the tool insulativity was covered, and refractory metals such as Mo, its surface can not produce oxidation yet in the sputter environment even be exposed to.Therefore, be exposed to the metal level 42 of contact area, contact with carrying out resistance between the transparency electrode with the 1st electrode on being stacked on this metal level 42.In addition, transparency conducting layer is after film forming, and is general as shown in Figure 3, is patterned as according to each pixel shape independently, and obtains pixel electrode (the 1st electrode) 50 whereby.In addition, in each pixel region, behind formation the 1st electrode 50, form and finish the 1st substrate-side with whole of covered substrate by formed oriented films 60 such as polyimide.Afterwards, fit in the peripheral part of substrate after the 2nd substrate 200 that forms oriented film 260 separated with certain interval with the 1st substrate 100, again liquid crystal is enclosed between substrate and the acquisition liquid crystal indicator.
Then, semi-transmission type LCD is described.In above-mentioned, be illustrated in the reflection type LCD that forms reflection horizon 44 in the roughly universe in 1 pixel region.But the present invention is not only applicable to reflection-type, is applicable to semi-transmission type LCD simultaneously yet.
Near the plane of a pixel that Fig. 7 is presented at this kind semi-transmission type active-matrix LCD constitutes, and Fig. 8 shows that then the summary section of the LCD on the B-B line that is positioned at Fig. 7 constitutes.Be shown in the reflection type LCD of above-mentioned Fig. 3 and Fig. 4, reflection horizon 44 is formed on the roughly universe (not comprising the contact area with TFT) of 1 pixel region.With respect to this, in Fig. 7 and semi-transmission type LCD shown in Figure 8, in a pixel, be formed with: be lower than 100 by reflection horizon 44 and thickness
, or thickness about 750
To 1250
The reflector space that transparent the 1st electrode 50 of degree is laminated; And remove reflection horizon 44, only there is the light transmissive region of transparent the 1st electrode 50.
In this kind semi-transmission type LCD, the 1st electrode 50 is disposed at than reflection horizon 44 more close liquid crystal layer side, reflection horizon 44 is by natural oxide film 46 and the 1st electrode 50 insulation that are formed at directly over it, and removed to avoid hampering contacting between TFT110 and the 1st electrode 50 by this zone.Therefore, according to this kind semi-transmission type LCD, by work function close the 1st electrode 50 and the 2nd electrode 250, place therebetween and with good symmetry AC driving liquid crystal layer 300 and be able to respectively oriented film be held under the arm, simultaneously, by cooperating light intensity toggle lights on every side, show or transmission display and reflect.At this, the thickness of the 1st electrode 50 is set in above-mentioned scope, therefore can prevent to reflect the irregular colour that caused because of the 1st electrode 50 when showing or the reduction of reflectivity, also make reflection demonstration and transmission display reach high-quality standard simultaneously easily.
More than, LCD at reflection that possesses reflection horizon 44 or semi-transmission type describes, but by on-off element of the present invention (TFT), connection are applicable to for example EL display of other luminous display unit with the formation of metal level, reflection horizon and transparent the 1st electrode, can make the 1st transparent electrode bottom have reflection function, and be connected the TFT of the 1st electrode and lower floor really.Fig. 9 shows the cut-away section structure in each pixel of active-matrix type EL display of present embodiment.
The element that the EL display of Fig. 9 is adopted as the organic EL 90 of the use organic compound of light-emitting component, forms organic element layer 88 between anode 80 and negative electrode 86.Organic element layer 88 possesses the luminescent layer 83 that comprises the organic luminescence function molecule is at least arranged, and can constitute monolayer constructions will, 2 layers, 3 layers or more multi-layered multi-ply construction according to the characteristic of organic compound, illuminant colour etc.In example shown in Figure 9, organic element layer 88 is by anode 80 sides that are disposed at substrate-side 100, form positive hole transfer layer 82/ luminescent layer 83/ electron supplying layer 84 in regular turn, luminescent layer 83 is similarly complied with the indivedual patternings of each pixel with anode 80, positive hole transfer layer 82 utmost point electron supplying layers 84 are then identical with negative electrode 86, and the mode common with both full-pixel forms.In addition, at each anodized insulation of pixel adjacent chien shih, in the fringe region of anode 80, produce short circuit in order to prevent simultaneously, and the zone forms planarization insulating film 39 between the anode of pixel adjacent with upper strata negative electrode 86.
The organic EL 90 of the above-mentioned formation of tool is combined and excites luminescent organic molecule at luminescent layer 83 by 86 injected electrons of positive hole and negative electrode that anode 80 injected, and when luminescent organic molecule is got back to ground state the radiation light source.The light-emitting component of general as mentioned above 90 1 kinds of current drive-types of organic EL, 80 pairs of organic element layers 88 of anode need possess enough positive hole injectabilities, and use transparent conductive materials such as the high ITO of work function, IZO more.Therefore, as a rule, the light that is sent by luminescent layer 83 is seen through transparency carrier 100 and is penetrated in the outside by these transparent anode 80 side.But active-matrix type OLED display shown in Figure 9 owing to form reflection horizon 44 below anode 80, therefore can penetrate light by cathode side.
That is, in the display of Fig. 9, in order to the anode 80 of the TFT110, metal level 42, reflection horizon 44 and the organic EL 90 that drive organic EL 90, adopt and above-mentioned TFT110 shown in Figure 2, metal level 42, reflection horizon 44 and the identical formation of the 1st electrode 50.In addition, the thickness setting of the 1st electrode 50 is for being lower than
, or be about
Extremely
Degree.The negative electrode 86 of organic EL 90 uses transparent conductive materials such as ITO identical with anode 80 or IZO, or is as thin as and can forms (also peristome can be set) through metal material such as Al, the Ag of the degree of light.By forming this kind structure, can realize effectively penetrating towards the outside top ejaculation type structure of the light that luminescent layer 83 sent by negative electrode 86 sides.In addition, in pairing pixel, even carry out the luminous of R, G, B light, as long as with the thickness setting of anode 80 (the 1st electrode) in above-mentioned scope, no matter then it all can realize high reflectance for which kind of color, make the light that enters anode 80 sides, can in anode 80, not produce problems such as decay or irregular colour, and be able in reflection horizon 44, produce reflection, and penetrate by negative electrode 86 sides in the light that at last luminescent layer 83 is obtained.Therefore, can realize the demonstration that brightness is high.
In addition, more than explanation will the 1st transparent electrode be connected in the formation of TFT, still with the thickness setting of the 1st transparent electrode 50 for being lower than 100
Scope the time, can make the electrical resistance of the 1st transparent electrode become big, therefore than in this 1st transparent electrode is connected in TFT and drives liquid crystal, preferably the reflection horizon 44 with lower floor is connected in TFT, and actual use as the 1st electrode with this reflection horizon 44, and drive liquid crystal in the lump with the 2nd electrode.Certainly, when reflection horizon 44 is connected in TFT, with the thickness setting of the 1st transparent electrode 50 750
To 1250
Degree, also can obtain the good optical characteristic equally.For TFT being connected in above-mentioned reflection horizon 44, to drive liquid crystal, for example can be by adopting some at reflective pixel electrode to form can to guarantee with the Mo layer that is connected of top transparent electrode 50 etc., and the formation that reflective pixel electrode 44 is connected in TFT is realized.Or, at the 1st transparent electrode and reflective pixel electrode 44 is under the situation of non-electric connection, also can adopt: by the reflective pixel electrode 44 that is connected in TFT, the transparency electrode that natural oxide film insulated 50 of this reflective pixel electrode 44 will be covered, form electric capacity across this natural oxide film with reflective pixel electrode 44 and combine, relend by this electric capacity and will put on the structure of transparency electrode 50 in order to the voltage that drives liquid crystal by reflective pixel electrode.
General as mentioned above, according to present embodiment 1, as reflection-type or semi-transmission type LCD, in the time of must forming the reflection horizon in a side substrate-side, can will have the 1st electrode of equal characteristic and the equivalent locations that the 2nd electrode is configured in liquid crystal layer.In addition, be set at by thickness and be lower than the 1st transparent electrode
Or
Extremely
The thickness of degree, can prevent the irregular colour that caused because of the 1st electrode that is disposed at before the reflection horizon or the reduction of reflectivity, in addition, by in above-mentioned scope, increasing the generation that thickness can reduce the resistance of the 1st electrode and prevent to break.Therefore symmetry AC driving liquid crystal that not only can be good also can be realized high display quality simultaneously.
Then, drive the formation of transparency electrode 50 by above-mentioned electric capacity with reference to description of drawings, and with this as the 2nd embodiment.
Figure 10 shows the some as the plane formation of the 1st substrate-side of reflection-type active-matrix LCD in the reflection type LCD of the 2nd embodiment, and Figure 11 shows that the summary section of the LCD of the A-A line that is positioned at Figure 10 constitutes.In addition, in above-mentioned drawing, omit its explanation with the formation of the above-mentioned explanation of prosign mark.Be with the different part of above-mentioned formation: be connected with the source electrode of TFT110 by the reflecting electrode that reflective metal material constituted 44 that is formed at respectively on the planarization insulating film 38, and on this reflecting electrode 44, therebetween seize dielectric film 46 on both sides by the arms and form by the 1st transparent electrode 50 that transparent conductive material constituted that forms indivedual patterns.
In the gate electrode 32 of TFT110, apply signal (sweep signal) back and activate TFT110, whereby, for example the voltage of source electrode 40 sides will equal to put on the voltage data signal of drain electrode (data line) 36.Owing to be connected with the event of reflecting electrode 44 in the source electrode 40, so this source voltage is applied in reflecting electrode 44.
Reflecting electrode 44 by: formed natural dielectric film 46 is covered when sputtering method forms the 1st electrode 50 that transparent conductive material constituted of ITO or IZO etc. and the similar work function of the 2nd electrode 250 tools of the 2nd substrate-side, and seizes this dielectric film 46 on both sides by the arms and form the 1st transparent electrode 50.According to present embodiment, seize this dielectric film 46 on both sides by the arms and make reflecting electrode 44 and the 1st electrode 50 form electric capacity to combine, relend the pairing data voltage of displaying contents that will put on reflecting electrode 44 and put on the 1st electrode 50 by this electric capacity.
By using and the 2nd electrode 250 identical materials, material as the 1st electrode 50, electrode with identical work function is able to therebetween across oriented film 60,260 and be disposed on the liquid crystal layer 300, therefore can be by the 1st electrode 50 and the 2nd electrode 250 with good symmetry AC driving liquid crystal layer 300.But, even the work function of the 1st electrode 50 and the 2nd electrode 250 is incomplete same, as long as its degree of approximation reach can be good symmetry drive liquid crystal layer 300.For example: when the difference of the work function of two electrodes when the 0.5eV degree is following, even the driving frequency of liquid crystal below above-mentioned CFF, also can not produce problem such as glimpse, liquid crystal burns, and reached high-quality demonstration.
The 1st electrode 50 and the 2nd electrode 250 that meet above-mentioned condition for formation, for example can in the 1st electrode 50, use IZO (work function 4.7eV to 5.2eV) and in the 2nd electrode 250, use ITO (work function 4.7eV to 5.0eV), or make both opposite, in the selection of material, can consider technologic characteristics such as transmitance, pattern precision or manufacturing cost and select the employed material of each electrode respectively.
Reflecting electrode 44 uses Al, Ag or both alloys (being the Al-Nd alloy in the present embodiment) etc. to have the material of good reflection in its face side (liquid crystal layer side) at least.In addition, reflection horizon 44 can be the individual layer of metal material such as Al, or high melting point metal layer such as Mo is set with as the substrate layer that connects planarization insulating film 38.When forming above-mentioned substrate layer, because the connecting airtight property lifting of 38 of reflecting electrode 44 and planarization insulating films, thereby be able to the reliability of lift elements.In addition, in the formation of Figure 11, identical with the embodiment 1 of above-mentioned Fig. 4, form dip plane in each pixel region of planarization insulating film 38 on being formed at interlayer dielectric 34 with desirable angle, and by covering this planarization insulating film 38 and lamination reflecting electrode 44, and form identical dip plane on the surface of reflecting electrode 44.When forming above-mentioned dip plane, can assemble outer light and, for example can promote the display brightness of the front position of display in each pixel with its ejaculation with optimal angle, position.Certainly, above-mentioned dip plane there is no necessity of certain existence.
Reflecting electrode 44 is made of above-mentioned conductivity type material such as Al-Nd alloy, and is stacked on the 1st electrode 50 on this reflecting electrode 44, is electrically insulated with reflecting electrode 44.The reason that produces insulation is: when adopting IZO, ITO etc. as the material of the 1st above-mentioned electrode 50, both are by sputter and film forming.That is the reflecting electrode that is made of Al etc. by tanning by the sun in the sputter environment, and produces oxidation reaction on its surface, and is covered the event by natural oxide film (dielectric film) 46.
In the 2nd embodiment, with the reflecting electrode of the 1st substrate-side that drives liquid crystal in the known reflection type LCD in the same manner, reflecting electrode 44 is connected in TFT110 (being source electrode 40 at this).On the other hand, reflecting electrode 44 and the 1st electrode 50 form state of insulation by above-mentioned natural oxide film 46, and seize the natural oxide film 46 that is formed at therebetween on both sides by the arms, make reflecting electrode 44 and the 1st electrode 50 constitute the 2nd electric capacity (C2).In addition, the 1st electrode 50 and the 2nd electrode 250 of subtend configuration constitute the 1st electric capacity (pixel capacitance) (C1) by seizing liquid crystal layer 300 on both sides by the arms.The 1st electric capacity (C1) is general as shown in figure 12 with the 2nd electric capacity (C2), and in 1 pixel, the circuit that is electrically connected at AC power forms equivalence with connecting.At this
[formula 1]
V=V1 (the 1st capacitance voltage)+V2 (the 2nd capacitance voltage) ... (1)
Interelectrode capacitance C represents it with following formula (2).
[formula 2]
C＝ε×ε
0×(S/d)……(2)
(still, ε is specific inductive capacity, the ε of material between electrode
0For the specific inductive capacity in the vacuum, S are that capacity area, d are interelectrode distance)
Expression.In addition, V1 represents it with formula (3).
[formula 3]
V1＝(C2/C1)×V2……(3)
Can learn by formula (3),, can high voltage V1 be put on the 1st electric capacity by the 2nd electric capacity as C2 during much larger than C1.For example, when the capacitance of the 1st electric capacity and the 2nd electric capacity, when meeting the concerning of following formula (4),
[formula 4]
C2>100×C1……(4)
Can reach driving roughly the same when utilizing reflecting electrode 44 directly to drive liquid crystal layer 300 by the 1st electrode 50.At this, owing to the natural oxide film 46 that can form between reflecting electrode 44 and the 1st electrode 50 as thin as a wafer, even therefore small size also can be set at maximum value with the 2nd capacitance C2.Therefore the 2nd capacitor C 2 can meet above-mentioned formula (4).Especially, as shown in figure 10, in reflection type LCD because overlapping (capacity area) area of reflecting electrode 44 and the 1st electrode 50 is very big, so capacitance C2 also relatively change and reached the relation of above-mentioned formula (4) greatly.
In addition, for example,, preferably the area of reflecting electrode 44 and the 1st electrode 50 is set, made the area of the 1st electric capacity that is comply with the area S1 that each pixel forms the 1st electrode 50 of indivedual patterns for satisfying the relation of above-mentioned formula (4); With the area of the 2nd electric capacity that is the overlapping area S2 of reflecting electrode 44 and 1 electrode 50, met the relation of following formula (5).
[formula 5]
S2>0.1×S1……(5)
Certainly, reflecting electrode 44 and the 1st electrode 50 have the reflection type LCD shown in Figure 10 of area about equally, can meet the relation of above-mentioned formula (5) really.
In addition, in above-mentioned formula (4) and the formula (5), its loss of voltage is lower than 1%, for example, is 5 μ m at distance (thickness of the liquid crystal layer 300) d1 of the 1st electrode 50 and the 2nd electrode 250, the DIELECTRIC CONSTANT of liquid crystal layer
1(liquid crystal average dielectric constant) is 5, and distance (thickness of the natural oxide film 46 etc.) d2 that reflecting electrode 44 and the 1st electrode are 50 is 50nm, the specific inductive capacity that reflecting electrode 44 and the 1st electrode are 50 (natural oxide film and other average dielectric constant) ε
2Be to set up under 5 the condition.Even do not meet above-mentioned all conditions certainly, also can be by reflecting electrode 44 by incompatible driving the 1st electrode 50 of capacitive junctions.
Figure 13 shows that the summary plane of the semi-transmission type LCD of active-matrix type constitutes.Compare with the formation of above-mentioned Figure 10, its dissimilarity only is: the reflecting electrode 44 that is formed at the 1st electrode 50 lower floors is less than 1 pixel region, and has the zone that does not form reflecting electrode 44.Because the formation area of the reflecting electrode 44 in 1 pixel region is less, so compared to reflection type LCD, its 2nd electric capacity is less.But, the ratio between reflecting electrode 44 and the transparency electrode 50 apart from the thickness d 1 of d2 and liquid crystal layer, even one of percentage is also only arranged in above-mentioned example, the numerical value of C2 can meet above-mentioned formula (4).
In addition, two kinds of functions of semi-transmission type LCD essential performance light transmission function and light reflection function require further brightness to promote especially on reflection function, and reflecting electrode 44 in design at least must be greater than 10% of 1 pixel region area.Therefore, the condition of above-mentioned formula (5) also can meet this requirement.
As mentioned above, even semi-transmission type LCD as long as utilize and the identical structure (manufacture method) that is connected of reflection-type, is connected in pixel TFT 110 with reflecting electrode 44 and gets final product.In addition, by natural oxide film 46 directly being remained between reflecting electrode 44 and the 1st electrode 50, can will put on the 1st electrode 50 corresponding to the voltage of displaying contents by reflecting electrode 44 by the 2nd electric capacity (C2) that is formed between reflecting electrode 44 and the 1st electrode 50.Certainly, be formed at than reflecting electrode 44 more close liquid crystal layer 300 sides, therefore can under the good situation of symmetry, drive liquid crystal layer 300 by the 1st electrode 50 and the 2nd electrode 250 by the 1st electrode 50 that transparent conductive material constituted.Therefore, cost that can be very cheap improves the symmetry of liquid crystal drive and promotes display quality.In addition,, also can form the 2nd electric capacity that is enough to drive the 1st electrode 50, and when using, can obtain sufficient brightness equally as infiltration type LCD even do not strengthen reflecting electrode especially.
In addition, in the formation of above-mentioned the 2nd embodiment, the thickness of the 1st electrode 50 preferably as the 1st above-mentioned embodiment, is set in
Extremely
(be preferably in
Extremely
Between) scope or
Extremely
Scope in, thus, can prevent irregular colour and obtain the good optical characteristic.
As above-mentioned, in the 2nd embodiment, no matter be the 1st substrate-side or the 2nd substrate-side, dispose the 1st and the 2nd electrode that is constituted by the similar transparent conductivity material of work function at its liquid crystal phase offside respectively, therefore can under good symmetry, drive liquid crystal layer by the 1st electrode and the 2nd electrode.The lower floor of this external the 1st electrode, formation is connected with on-off element, and in order to reflect the reflection of light electrode that the 2nd substrate-side is injected.
The 1st electrode because of and reflecting electrode between the existence of dielectric film such as formed natural oxide film, and be able to be electrically insulated with this reflecting electrode, electric capacity (the 2nd electric capacity) by two electrodes are constituted can be applied and the pairing voltage of displaying contents voltage about equally the 1st electrode by reflecting electrode.In addition, existence by reflecting electrode, except can constituting reflection-type or semi-transmission type LCD,, also need not change the structure that is connected of reflecting electrode and on-off element in the reflection type LCD even must on reflecting electrode, form the 1st transparent electrode in order to realize high symmetric liquid crystal drive.Therefore, not only can realize deleting of manufacturing cost, can under simple formation, obtain the reflection-type or the semitransparent liquid crystal display of display quality height and low consumption electric power simultaneously.
Claims (14)
1. liquid crystal indicator possesses the 1st substrate of the 1st electrode and possesses and encloses liquid crystal layer between the 2nd substrate of the 2nd electrode and constitute in each pixel, to carry out the demonstration of each pixel, it is characterized in that:
Described the 1st substrate also possesses and has:
Be arranged at the on-off element in each pixel; And
Reflecting electrode, part ground covers a pixel region, and electrically connects with this on-off element on described on-off element, and will be reflected from the light that the 2nd substrate-side is incident in described liquid crystal layer;
On described reflecting electrode, and form the transparency electrode that constitutes by transparent conductive material across dielectric film between described reflecting electrode, this transparency electrode is to form capacitive coupling as described the 1st electrode with described reflecting electrode, supplying to the voltage of described reflecting electrode by described on-off element, is to put on described transparency electrode by the electric capacity that described reflecting electrode and described the 1st electrode were constituted that disposes in the mode of seizing described dielectric film between the two on both sides by the arms.
2. liquid crystal indicator as claimed in claim 1 is characterized in that:
The work function of the described transparent conductivity material of described the 1st electrode, with the difference of the work function of the transparent conductivity material of described the 2nd electrode of the liquid crystal layer side that is formed at described the 2nd substrate below 0.5eV.
3. liquid crystal indicator as claimed in claim 2 is characterized in that:
The driving frequency of the liquid crystal layer in each pixel is lower than 60Hz.
4. liquid crystal indicator possesses the 1st substrate of the 1st electrode and possesses and encloses liquid crystal layer between the 2nd substrate of the 2nd electrode and constitute in each pixel, to carry out the demonstration of each pixel, it is characterized in that:
Described the 1st substrate also possesses and has:
Be arranged at the on-off element in each pixel; And
Reflecting electrode electrically connects with this on-off element on described on-off element, and will be reflected from the light that the 2nd substrate-side is incident in described liquid crystal layer;
On described reflecting electrode, and form the transparency electrode that constitutes by transparent conductive material across dielectric film between described reflecting electrode, this transparency electrode is to form capacitive coupling as described the 1st electrode with described reflecting electrode, supply to the voltage of described reflecting electrode by described on-off element, be to put on described transparency electrode by the electric capacity that described reflecting electrode and described the 1st electrode were constituted that disposes in the mode of seizing described dielectric film between the two on both sides by the arms
The capacitance C1 of the pixel capacitance that described the 1st electrode of therebetween seizing described liquid crystal layer on both sides by the arms and being relative to the configuration and described the 2nd electrode are constituted, and the capacitance C2 of the electric capacity that is made of described reflecting electrode and described the 1st electrode meet
C2>100×C1
Relation.
5. liquid crystal indicator as claimed in claim 4 is characterized in that:
The work function of the described transparent conductivity material of described the 1st electrode, with the difference of the work function of the transparent conductivity material of described the 2nd electrode of the liquid crystal layer side that is formed at described the 2nd substrate below 0.5eV.
6. liquid crystal indicator as claimed in claim 5 is characterized in that:
The driving frequency of the liquid crystal layer in each pixel is lower than 60Hz.
7. liquid crystal indicator as claimed in claim 4 is characterized in that:
The thickness of described transparency electrode is 750
To 1250
Scope in.
8. liquid crystal indicator as claimed in claim 4 is characterized in that:
The thickness of described transparency electrode is 1
To 100
Scope in.
9. liquid crystal indicator possesses the 1st substrate of the 1st electrode and possesses and encloses liquid crystal layer between the 2nd substrate of the 2nd electrode and constitute in each pixel, to carry out the demonstration of each pixel, it is characterized in that:
Described the 1st substrate also possesses and has:
Be arranged on the on-off element in each pixel; And
Reflecting electrode electrically connects with this on-off element on described on-off element, and will be reflected from the light that the 2nd substrate-side is incident in described liquid crystal layer;
On described reflecting electrode, and form the transparency electrode that constitutes by transparent conductive material across dielectric film between described reflecting electrode, this transparency electrode is to form capacitive coupling as described the 1st electrode with described reflecting electrode, supply to the voltage of described reflecting electrode by described on-off element, be to put on described transparency electrode by the electric capacity that described reflecting electrode and described the 1st electrode were constituted that disposes in the mode of seizing described dielectric film between the two on both sides by the arms
The area S1 of described the 1st electrode of therebetween seizing described liquid crystal layer on both sides by the arms and being relative to the configuration with described the 2nd electrode, the described reflecting electrode that is relative to the configuration with therebetween seizing described dielectric film on both sides by the arms and the overlapping area S2 of described the 1st electrode meet
S2>0.1×S1
Relation.
10. liquid crystal indicator as claimed in claim 9 is characterized in that:
The work function of the described transparent conductivity material of described the 1st electrode, with the difference of the work function of the transparent conductivity material of described the 2nd electrode of the liquid crystal layer side that is formed at described the 2nd substrate below 0.5eV.
11. liquid crystal indicator as claimed in claim 9 is characterized in that:
The driving frequency of the liquid crystal layer in each pixel is lower than 60Hz.
12. liquid crystal indicator as claimed in claim 9 is characterized in that:
The thickness of described transparency electrode is 750
To 1250
Scope in.
13. liquid crystal indicator as claimed in claim 9 is characterized in that:
The thickness of described transparency electrode is 1
To 100
Scope in.
14. a luminous display unit is formed at the interarea side of substrate, and has light-emitting component, this light-emitting component possesses the 1st electrode, light emitting element layer and the 2nd electrode, it is characterized in that:
On described substrate, form in order to reflection by the reflection of light layer of described light emitting element layer or the incident of described the 2nd electrode side institute with as described the 1st electrode,
By transparent conductive material constituted and thickness 1
To 100
Scope in transparency electrode, cover described reflection horizon and form,
Between described reflection horizon and described substrate, also in each pixel, on-off element is set,
This on-off element is connected with the described reflection horizon that constitutes described the 1st electrode, interlayer in described reflection horizon and described transparency electrode forms dielectric film, described transparency electrode sees through this dielectric film and described reflection horizon forms capacitive coupling, supplying to the voltage in described reflection horizon by described on-off element, is the electric capacity that constituted of the described reflecting electrode that disposes by seizing described dielectric film on both sides by the arms and described transparency electrode and put on described transparency electrode.
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| JP2002057306A JP3953338B2 (en) | 2002-03-04 | 2002-03-04 | Liquid crystal display |
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| JP2006091063A (en) * | 2004-09-21 | 2006-04-06 | Casio Comput Co Ltd | Liquid crystal display element |
| CN101124509B (en) * | 2005-02-21 | 2010-12-08 | 奇美电子股份有限公司 | LCD with reduced flicker and a method for manufacturing thereof |
| TWI341948B (en) | 2005-05-20 | 2011-05-11 | Epson Imaging Devices Corp | Display device |
| TW200641465A (en) | 2005-05-20 | 2006-12-01 | Sanyo Epson Imaging Devices Co | Display device |
| US7429753B2 (en) | 2005-05-20 | 2008-09-30 | Sanyo Electric Co., Ltd. | Display device |
| JP2007183452A (en) * | 2006-01-10 | 2007-07-19 | Epson Imaging Devices Corp | Translucent liquid crystal display device |
| KR101264717B1 (en) | 2007-03-26 | 2013-05-16 | 엘지디스플레이 주식회사 | Liquid Display Pnel of Transflective Type And Fabricating Method Thereof |
| JP6808335B2 (en) | 2016-03-11 | 2021-01-06 | 株式会社ジャパンディスプレイ | Liquid crystal display device |
-
2002
- 2002-03-04 JP JP2002057306A patent/JP3953338B2/en not_active Expired - Lifetime
-
2003
- 2003-03-04 CN CNB200510080737XA patent/CN100523963C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JP3953338B2 (en) | 2007-08-08 |
| CN101030003A (en) | 2007-09-05 |
| JP2003255375A (en) | 2003-09-10 |
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