WO2001046720A1

WO2001046720A1 - Elliptical polarizing plate, method for producing the same, and liquid crystal display comprising the same

Info

Publication number: WO2001046720A1
Application number: PCT/JP2000/009097
Authority: WO
Inventors: Toshihiro Ichizuka; Hiroyasu Ishikawa
Original assignee: Nippon Petrochemicals Co., Ltd.
Priority date: 1999-12-22
Filing date: 2000-12-21
Publication date: 2001-06-28
Also published as: TW556024B; WO2001046720A8

Abstract

An elliptical polarizing plate having a liquid crystal polymer layer and a polarizing element by a method comprising the steps of forming the liquid crystal polymer layer on a cellulose triacetate film, forming a translucent overcoat layer on the liquid crystal polymer layer, performing saponification to fabricate an optical anisotropic element, and bonding a polarizing film to the optical anisotropic element with an adhesive layer in such a way as to sandwich the polarizing film between the optical anisotropic element and a translucent protective film or by a method comprising the step of bonding a polarizing element to the liquid crystal polymer layer formed on a separable substrate continuously with a tacky adhesive layer.

Description

Description Elliptical polarizing plate, method for producing the same, and liquid crystal display device using the same [Technical field to which the invention pertains]

The present invention relates to an elliptically polarizing plate used to enhance the display performance of a liquid crystal display device, a method for manufacturing the same, and a liquid crystal display device using the same.

[Conventional technology]

Liquid crystal display devices have the advantages of thinness, light weight, and low power consumption.However, for example, complete black-and-white display has not been achieved with the STN type liquid crystal display device. At present, liquid crystal display devices with excellent display performance have not yet been realized.

Some means for improving the display performance of the liquid crystal display device have been proposed. One of them is to arrange a retardation film between the polarizing plate and the liquid crystal cell of the liquid crystal display device. This method has an advantage that the method can be easily carried out simply by bonding a retardation film to a polarizing plate to form an elliptically polarizing plate without significantly changing the manufacturing process of the liquid crystal display device. However, the thickness is increased by the amount of the retardation film and the adhesive layer for laminating the retardation film, and when wound into rolls in the manufacturing process of elliptically polarizing plates, the amount of winding per roll is reduced and productivity is poor. And the thickness of the liquid crystal layer and the thickness of the final product increase.

In addition, since the layers are composed of multiple layers of different types, the interface between the polarizing plate and the retardation film may peel off under high-temperature or high-humidity conditions due to differences in the expansion and contraction behavior of each layer due to heat and humidity. Was.

Conventionally, most retardation films use polymer films in which polycarbonate and the like are uniaxially stretched and oriented, and their orientation axes in a long film form are usually limited to the stretching direction, that is, the MD direction. . On the other hand, since the polarizing plate also uses a uniaxially stretched film such as polyvinyl alcohol, the absorption axis in a long film form is usually limited to the MD direction. Therefore, when an elliptically polarizing plate is manufactured by continuously laminating a polarizing plate and a retardation film from a long film form, it is limited to a special case where the absorption axis of the polarizing plate and the orientation axis of the retardation film are parallel. Was. parallel In order to arrange the shafts other than the above, it was necessary to cut and bond the long film into a sheet shape, and there was a problem that the process was complicated and productivity was poor. Furthermore, in the stretched and oriented retardation film, it was difficult to freely control the orientation of the polymer, and the degree of freedom of the optical characteristics was limited. As described above, it was not possible to sufficiently respond to the demand for an elliptically polarizing plate having excellent optical performance due to various arrangements of the absorption axis of the polarizing plate and the orientation axis of the retardation film.

JP-A-4-157017 and JP-A-6-224317 propose an optically anisotropic element in which a liquid crystalline polymer is fixed in orientation. When such a liquid crystalline polymer is used, since the orientation axis angle can be set arbitrarily, various elliptically polarizing plates can be manufactured by continuously laminating a long film form. However, as described above, the thickness of the elliptically polarizing plate may increase, and the interface between the polarizing plate and the optically anisotropic element may be broken under high-temperature or high-humidity conditions.

Japanese Patent Application Laid-Open No. Hei 8-277841 describes a liquid crystal polymer layer transferred onto a peelable substrate. This method may simplify the layer structure and reduce the total film thickness, but if an elliptically polarizing plate with excellent optical performance, quality, and durability under high temperature and high humidity conditions cannot be obtained, There was.

[Object of the invention]

An object of the present invention is to reduce the thickness by simplifying the layer structure of an elliptically polarizing plate, to prevent problems such as peeling even under high temperature and high humidity conditions, and to further improve optical characteristics. Elliptically polarizing plate that can be continuously bonded from a long film by setting the orientation axis angle of the element to the absorption axis of the polarizing plate, a method of manufacturing the same, and a liquid crystal display using the same It is to provide a device.

[Summary of the Invention]

A first aspect of the present invention is an elliptically polarizing plate having a liquid crystal polymer layer and a polarizing element, wherein the optically anisotropic element (a) having a liquid crystal polymer layer oriented on a cellulose triacetate film and a light-transmitting protective element are provided. An elliptically polarizing plate characterized in that a polarizing element is sandwiched between the film and the film (b), and the optically anisotropic element is subjected to a vulcanization process.

A second aspect of the present invention is the above-mentioned elliptically polarizing plate, wherein a light-transmitting overcoat layer is provided on the surface of the liquid crystal polymer layer. A third aspect of the present invention is the above-mentioned elliptically polarizing plate, wherein the light-transmitting overcoat layer is made of an acryl-based resin.

A fourth aspect of the present invention resides in the above-mentioned elliptically polarizing plate, wherein the liquid crystal polymer layer is made of optically positive uniaxial liquid crystal molecules.

A fifth aspect of the present invention is the above-mentioned elliptical polarization, wherein the orientation direction of the liquid crystal polymer near one of the two surfaces of the liquid crystal polymer layer is not parallel to the MD direction.

A sixth aspect of the present invention is the above-mentioned elliptically polarizing plate, wherein the optically anisotropic element, the translucent protective film, and the polarizing element are in the form of a long film.

A seventh aspect of the present invention is to form a liquid crystal polymer layer on a cellulose triacetate film,

Then, an optically anisotropic element is manufactured by providing a translucent overcoat layer on the surface of the liquid crystal polymer layer, and then the optically anisotropic element is subjected to a vulcanization treatment. Thereafter, the polarizing film is interposed with an adhesive layer. And bonding the optically anisotropic element and the light-transmitting protective film so as to be sandwiched therebetween.

An eighth aspect of the present invention resides in a liquid crystal display device characterized in that the elliptically polarizing plate is disposed on at least one surface of a liquid crystal cell.

A ninth aspect of the present invention is a method for producing an elliptically polarizing plate having a liquid crystal polymer layer and a polarizing element, wherein the liquid crystal polymer layer supported on a substrate which can be separated from the polarizing element is separated by an adhesive layer. A method for manufacturing an elliptically polarizing plate characterized by laminating.

A tenth aspect of the present invention is the ninth method, wherein the surface of the liquid crystal polymer layer formed on the removable substrate is protected by a transparent overcoat layer.

The eleventh aspect of the present invention resides in the tenth method, wherein the translucent overcoat layer is made of an acrylic resin.

A twelfth aspect of the present invention is the method according to any one of the ninth to eleventh aspects, wherein the liquid crystal polymer layer is made of optically positive uniaxial liquid crystal molecules.

A thirteenth aspect of the present invention is the liquid crystal display device according to the ninth to eleventh features, wherein the alignment direction of the liquid crystal polymer in the vicinity of one of the two side surfaces of the liquid crystal polymer layer is not parallel to the MD direction. Is in one of the ways.

According to a fourteenth aspect of the present invention, a liquid crystal polymer layer supported on a removable substrate is a long filter. The present invention is directed to any one of the ninth to thirteenth methods in which the bonding is performed continuously in a lume form.

A fifteenth aspect of the present invention is a liquid crystal display device characterized in that an elliptically polarizing plate manufactured by any one of the ninth to fourteenth methods is disposed on at least one surface of a liquid crystal cell. Oh

[Brief description of drawings]

A typical example of the elliptically polarizing plate of the present invention and a typical example of the manufacturing method thereof will be described.

[Embodiment of the invention]

In FIG. 1, A shows the above-described first to eighth typical examples of the present invention, and B shows the ninth to 13th typical examples. In the figure, “protective film (T AC)” is a protective film, and a typical example thereof is a cellulose triacetate (T AC) film. "Polarizing film" indicates a typical example of a polarizing element. “O C layer” means (translucent) over-coat layer. “Trip adhesive” means either an adhesive or an adhesive.

Preferred embodiments of the present invention will be described in detail below.

The liquid crystal polymer layer used in the elliptically polarizing plate of the present invention can be obtained, for example, by cooling a liquid crystal polymer oriented on an alignment treatment substrate to a glass transition temperature (T g) or lower and fixing the orientation. Can be As such a liquid crystal polymer, a thermotropic liquid crystal polymer which exhibits liquid crystallinity when melted is used. The thermotropic liquid crystal polymer used must be able to maintain the molecular alignment state of the liquid crystal phase even when cooled from the molten state (liquid crystal state) to Tg or less.

The liquid crystal phase of the liquid crystal polymer when melted may have any molecular arrangement structure such as smectic, nematic, twisted nematic, and cholesteric.The liquid crystal phase has a homogenous alignment and a homeotropic alignment near the alignment substrate and the air interface, respectively. There may be a so-called hybrid orientation in which the average director of the liquid crystal polymer is inclined from the normal direction of the film.

As the liquid crystal polymer, for example, a liquid crystal polymer having a mesogen in the main chain such as polyester, polyamide, polycarbonate, and polyesterimide, or a side of polyacrylate, polymethacrylate, polymalonate, polysiloxane, etc. Examples thereof include a liquid crystal polymer having a mesogen in a chain. As the polyester, a polymer containing an orf-substituted aromatic unit as a constituent component is most preferable, but a polymer containing as a constituent component an aromatic unit having a bulky substituent in place of the ortho-substituted aromatic unit can also be used. Twisted nematic alignment can be achieved by introducing an optically active unit into the liquid crystal polymer chain or by blending an optically active compound. Even oligomers and low molecular weight compounds are thermally crosslinked or photocrosslinked in a state where they are cooled to a liquid crystal state or liquid crystal transition temperature or lower and are fixed in orientation by introducing a crosslinkable group or blending an appropriate crosslinking agent. Liquid crystal polymers that can be polymerized by such means are also included in the liquid crystal polymers. Further, even a discotic liquid crystal compound can be used without any problem.

As the liquid crystal polymer, one having optically positive or negative uniaxiality is usually used. Their optical properties are appropriately selected depending on the functions required of the elliptically polarizing plate. In the case of a liquid crystal polymer layer having a twisted nematic orientation, a liquid crystal polymer exhibiting positive uniaxiality is preferably used. .

The T g of the liquid crystal polymer is preferably room temperature or higher, and more preferably 50 ° C. or higher, since it affects the alignment stability after the alignment is fixed. T g can be adjusted by the type of monomer used in the liquid crystal polymer, monomer ratio, polymerization conditions and the like, but can also be adjusted by using the above-mentioned crosslinking means in combination. The triacetate cell aperture film used for the optically anisotropic element of the embodiment A of FIG. 1 (the first to eighth aspects of the present invention) is basically used as a transparent support film, and the elliptically polarizing plate mainly has a color. When used for compensation, it is desirable that the optical anisotropy be as small as possible. When used for viewing angle compensation, those having optical characteristics that complement the optical characteristics of the liquid crystal polymer layer can be used, and those that are optically negative uniaxial or biaxial are usually used. Can be

A method for forming a liquid crystal polymer layer on a cellulose triacetate film includes a method in which a liquid crystal polymer is aligned on an alignment-treated cellulose triacetate film and a liquid crystal polymer layer is directly formed on the film. There is a method b in which a liquid crystal polymer is oriented on another orientation substrate to form a liquid crystal polymer layer, and then the layer is transferred onto a cellulose triacetate film. In the case of method a, a cellulose triacetate film provided with an organic or inorganic alignment film is preferably used. Examples of the organic alignment film include a polyvinyl alcohol-polyimide derivative. The surface provided with the alignment film is subjected to an alignment process such as a rubbing process.

In the case of Method b, the alignment substrate may be, for example, a thermosetting resin such as polyimide, epoxy resin, or phenol resin, a polyamide such as nylon; a polyether imide; a polyether ketone; a polyether ether ketone (PEEK); Polyketone; Polyether sulfone; Polyphenylene sulfide; Polyphenylene oxide; Polyester such as polyethylene terephthalate and polybutylene terephthalate; Polyacetal; Polyacrylonitrile; Poly (meth) acrylate; A polymer film exemplified by a thermoplastic resin such as polyvinyl alcohol can be used. Further, an organic thin film made of another resin described above may be formed on the surface of the polymer film. The polymer film is subjected to an orientation treatment such as a rubbing treatment and provided to an oriented substrate. Such an alignment substrate is also used in the embodiment B. Usually, such an alignment substrate is not suitable for use in an optically anisotropic element from the viewpoint of optical isotropic properties, translucency, and physical characteristics. Therefore, a liquid crystal polymer layer is formed on a cellulose triacetate film. To obtain an optically anisotropic element.

In the embodiments A and B of FIG. 1, a rubbing treatment is usually applied to align a liquid crystal polymer on an alignment substrate (hereinafter, including cellulose triacetate film). Hereinafter, the rubbing process will be described in the case of a long film form. The rubbing treatment can be performed at a predetermined arbitrary angle with respect to the MD direction of the long oriented substrate. The angle of the rubbing direction with respect to the MD direction is appropriately set according to the function of the elliptically polarizing plate. However, when a function as a color compensator is required, the rubbing is usually performed in an oblique direction with respect to the MD direction. Is preferred.

The angle of the oblique direction is preferably in the range of 144 degrees to +45 degrees.

The rubbing treatment can be performed by an arbitrary method, for example, a rubbing roll is arranged at an arbitrary angle with respect to the MD direction of the long film on a stage for transporting the long film in the MD direction, and the film is removed. The rubbing roll is rotated while being conveyed in the MD direction, and the film surface is rubbed. Rubbing roll and stage This is a mechanism that can freely adjust the angle formed by the moving direction of the rubbing roll, and an appropriate rubbing cloth material is attached to the surface of the rubbing roll.

Next, as a method of forming a liquid crystal polymer layer by bringing the liquid crystal polymer into contact with the rubbed surface of the alignment substrate, for example, a method of dissolving the liquid crystal polymer in an appropriate solvent, coating and drying, or A method of directly extruding a liquid crystal polymer with a T-die or the like is used. From the viewpoint of the uniformity of the film thickness, a method of applying a solution and drying is appropriate.

The method for applying the liquid crystal polymer solution is not particularly limited, and examples thereof include a die coating method, a slot die coating method, a slide die coating method, a roll coating method, and a bar coating method.

A dipping pulling method or the like can be adopted.

After the application, the solvent is removed by an appropriate drying method to form an unoriented liquid crystal polymer layer. Next, the liquid crystal polymer is oriented by heating at a predetermined temperature for a predetermined time, and then cooled to a temperature of T g or less to form a liquid crystal polymer layer having a fixed orientation. The thickness is not particularly limited as long as the function of the elliptically polarizing plate is exhibited, and is approximately 0.05 m to 100 / m, preferably approximately 0.1 001 to 3001. is there.

In the embodiment A of FIG. 1, when transferring the liquid crystal polymer layer from the alignment substrate to the cellulose triacetate film, it can be carried out using an appropriate adhesive. Any adhesive can be used as long as it is translucent and optically isotropic, and examples thereof include acrylic, epoxy, ethylene monoacetate, and rubber adhesives. In particular, an acrylic adhesive is preferably used.

The liquid crystal polymer layer having a fixed orientation formed on the cellulose triacetate film is made of a light-curing, electron beam-curing or thermosetting acrylic resin to protect the surface. An overcoat layer is provided. When the liquid crystal polymer layer is formed by a method such as crosslinking, it may not be necessary to provide a translucent overcoat layer.

In the embodiment A of FIG. 1 (first to eighth aspects of the present invention), an elliptically polarizing plate is manufactured by using an optically anisotropic element as a protective film for a polarizing element. To do Therefore, the number of layers constituting the elliptically polarizing plate can be reduced as compared with the case where the optically anisotropic element is bonded to the polarizing plate whose both sides of the polarizing element are protected by the cellulose triacetate film. As a result, the influence of shrinkage strain of each layer due to heat or humidity is reduced, and defects such as peeling at the bonded interface can be eliminated. However, it is difficult to bond an ordinary optically anisotropic element having a liquid crystal polymer layer on a cellulose triacetate film to a polarizing element. In the present invention, the problem is solved by changing the optical anisotropic element, and the object of the present invention can be effectively achieved as a whole.

In the embodiment shown in FIG. 1A, the optically anisotropic element is subjected to a curing treatment before bonding to the polarizing element. The aging treatment is usually performed by contacting with an aqueous alkali solution. As the aqueous alkali solution, potassium hydroxide, sodium hydroxide, or the like is used. The concentration of the alkali is about 0.1 to 10%, preferably about 0.5 to 5%, and more preferably about 1 to 3%. A dilute solution of about% is sufficient. As the treatment conditions, mild conditions of 1 to 60 minutes at room temperature, preferably 30 minutes or less, more preferably 15 minutes or less are sufficient. If the overcoat layer is provided on the liquid crystal polymer layer, the liquid crystal polymer layer is not eroded or damaged in the curing step.

As the polarizing element used in the present invention, an element obtained by adsorbing a polarizing element such as iodine or a dichroic dye on a base material such as a stretched PVA film is generally used. In general, a polarizing element is formed as a polarizing plate with both sides sandwiched by protective films, and usually, a single film of triacetate cell orifice is used as the protective film. In the embodiment A of FIG. 1, an elliptically polarizing plate can be obtained by using the above-described optically anisotropic element as a protective film on at least one surface of the polarizing element.

The polarizing element and the optically anisotropic element are bonded together with an acrylic, SBR, or silicone adhesive or adhesive. The optically anisotropic element can be bonded to the polarizing element either on the liquid crystal polymer layer side where the translucent overcoat layer is provided or on the cellulose triacetate film side. And a polarizing element are preferably attached to each other.

As the translucent protective film used in the present invention, the above optically anisotropic element is used. Power that can be used \ It is preferable to use a light-transmissive film with low optical anisotropy, which is marketed under the trade names of ZONEX, ART〇N, FUJITAC, etc., with small birefringence. The translucent protective film and the polarizer are formed in the same manner as in the case of bonding an optically anisotropic element.

In the embodiment of FIG. 1B (ninth to fifteenth aspects of the present invention),

The liquid crystal polymer layer formed on the alignment substrate film is then transferred to a removable substrate. This method is a method in which the liquid crystal polymer layer is transferred to a detachable substrate by using an appropriate adhesive. This adhesive layer is optically isotropic, has an adhesive force on both the liquid crystal polymer layer and the peelable substrate after curing, and has another substrate bonded to the liquid crystal polymer layer side. In this case, there is no particular limitation as long as the detachable substrate can be detached even after bonding. Examples of such adhesives include photo-curable, electron beam-curable, and thermo-curable adhesives, and among them, photo-curable acrylic adhesives are preferred. The cured adhesive layer also functions as an overcoat layer for protecting the liquid crystal polymer layer.

The releasable substrate used in the present invention is not particularly limited as long as it is a substrate having releasability and self-supporting property, but usually, a plastic film is used. The term “releasability” as used in the present invention means that, when the liquid crystalline polymer layer and the substrate are bonded via an adhesive, an appropriate adhesive force is maintained, and when the substrate is separated, the resin is cured. It means that separation is possible at the interface between the adhesive layer and the substrate. The peelable substrate film used in the present invention usually has a peel strength at an interface with an adhesive (after curing) of 180 ° (a 180 ° peel test, a peeling speed of 30 cmZ), which is usually 0.1 μm. 5 to 8 ON / 25 mm. Preferably, a separation strength of 2 to 50 NZ 25 mm is used. Specific examples of the plastic film suitable as the detachable substrate include polyethylene, polypropylene, and olefin-based resins such as 4-methylpentene-11 resin, polyamide, polyimide, polyamide amide, polyether imide, and polyether imide. Ether ketone, polyether ether ketone, polyether sulfone, polyketone sulfide, polysulfone, polystyrene, polyphenylene sulfide, polyphenylene oxide, polyethylene terephthalate, polybutylene terephthalate, polyarylate, polyacetal, polycarbonate The Poly Binni Alcohol, cellulosic plastics and the like.

These plastic films may be used by themselves, or those coated with silicone, organic or inorganic thin films, or chemically-coated ones to provide appropriate release properties. Those that have been subjected to a treatment or those that have been subjected to a physical treatment such as corona discharge treatment can be used. In the present invention, polypropylene, polyether ether ketone, polyethylene terephthalate, polycarbonate, and plastic films obtained by subjecting these film surfaces to silicone treatment or corner discharge treatment have both an adhesive and appropriate adhesiveness and releasability. This is desirable.

A liquid crystal polymer layer formed on a substrate that can be separated from the polarizing element and whose surface is protected by a translucent overcoat layer is an adhesive represented by an acrylic, SBR, or silicon Alternatively, the elliptically polarizing plate of the present invention is obtained by laminating with an adhesive. In order to protect the surface of the liquid crystal polymer layer, a light-transmitting overcoat layer made of a photocurable, electron beam-curable or thermosetting acryl-based resin is provided. If an elliptically polarizing plate is manufactured without providing a light-transmitting overcoat layer, the liquid crystal polymer layer may be damaged, and an elliptically polarizing plate with excellent optical performance and quality may not be obtained. When the liquid crystal polymer layer is formed by a method such as crosslinking, it may not be necessary to provide a light-transmitting overcoat layer. The polarizing element may be supplied in a form in which both sides are protected by a triacetate cell mouth film, or after the polarizing element and the liquid crystal polymer layer are directly bonded, the peelable substrate film is removed, and then Both sides of the polarizing element side and the liquid crystal polymer layer side may be protected with a cellulose triacetate film. In any case, an elliptically polarizing plate can be obtained by removing the substrate film that can be separated at an appropriate time after lamination with the polarizing element.

In the present invention, in both the embodiments A and B, the liquid crystal polymer layer (optically anisotropic element) can be continuously supplied in the form of a long film. The lamination operation can be performed continuously. When stacking the liquid crystal polymer layer (optically anisotropic element) and the polarizing element, it is necessary to stack the transmission axis of the polarizing element and the alignment axis near either one of the two interfaces of the liquid crystal polymer layer at a specific angle. However, since the liquid crystal polymer layer of the present invention can set the orientation angle in any direction, It is possible to laminate one after the other in the MD direction. When the elliptically polarizing plate of the present invention is arranged in a liquid crystal cell, it is necessary that the liquid crystal polymer layer side of the elliptically polarizing plate be on the liquid crystal cell side.

The elliptically polarizing plate in the present invention includes a so-called circularly polarizing plate and a linearly polarizing plate.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to examples.

Preparation of liquid crystal polymer solution 1:

20 \ ^% of 1 ^ -methylpyrroli, including the mixed polymer shown by the formula (I) (logarithmic viscosity of base polymer = 0.21, Tg = 60 ° C, logarithmic viscosity of optically active polymer = 0.18) A don solution was prepared.

(I)

97.2 w t%

2.8 wt%

* Indicates optically active carbon.

Preparation of liquid crystal polymer solution 2 A 1 Owt% methylene chloride solution of the side chain type acrylic polymer represented by the formula (II) was prepared.

(I)

C≡N

n ^ 1 8

Preparation of liquid crystal polymer solution 3:

A 7 wt% solution of the liquid crystalline polyester represented by the formula (III) (logarithmic viscosity = 0.16, Tg = 1100 ° C.) was prepared.

(1)

Preparation of optical anisotropic element A:

While transporting a long PEEK film with a width of 65 mm and a thickness of 100 m, a rubbing roll of 150 mm ø around which a rayon cloth is wound is set at an angle, and continuously rotated by rotating at high speed. Perform rubbing, and align the substrate with a rubbing angle of 45 °. I got Irum. Here, the rubbing angle is an angle clockwise from the MD direction when the rubbing surface is viewed from above. The solution obtained in Liquid Crystal Polymer Solution Preparation Example 1 was continuously applied on the alignment substrate film using a die coater and dried to form an unoriented liquid crystal polymer layer. The liquid crystal polymer was aligned by heat treatment at 100 ° C. for 10 minutes, and then cooled to room temperature to fix the alignment. This liquid crystal polymer layer had a twisted nematic orientation, a twist angle of 230 ° and an And of 0.84 m. The liquid crystal polymer layer was transferred to an uncured 80 m-thick cellulose triacetate film using an ultraviolet-curable acrylic adhesive. The same acryl-based adhesive was applied to the surface of the liquid crystal polymer layer for surface protection and then cured to form a light-transmitting overcoat layer. As described above, an optically anisotropic element A having a total thickness of about 100 μm was obtained.

Preparation of optically anisotropic element B:

Alkyl-modified polyvinyl alcohol is applied to a long, 80-inch thick cellulose triacetate film that has not been subjected to oxidation treatment, dried, and then subjected to a rubbing treatment in the same manner as in the production example of optical anisotropic element A. Thus, an oriented substrate film having a rubbing angle of 45 ° was obtained. The solution prepared in Preparation Example 2 of the liquid crystal polymer solution was applied to the alignment substrate film, dried, and then subjected to a heat alignment treatment to fix the alignment of the liquid crystal polymer layer. This liquid crystal polymer layer was in a nematic orientation, and the An was 0.8 μm. An UV-curable acrylic adhesive was applied to the liquid crystal polymer layer side for surface protection to obtain an optically anisotropic element B having a total thickness of about 100 / m.

Preparation of optically anisotropic element C:

While transporting a long PEEK film with a width of 600 mm and a thickness of 100 m, the rotation direction of the rubbing roll of 150 mm ø around which the rayon cloth is wound is parallel to the MD direction. The rubbing was performed continuously by setting and rotating at high speed to obtain an oriented substrate film. The solution obtained in Liquid Crystal Polymer Solution Preparation Example 3 was applied onto the oriented substrate film using Daiko All Night, dried, and heated at 230 ° C for 10 minutes. The liquid crystal polymer was aligned and then fixed. It was confirmed that the film had a nematic hybrid orientation with a film thickness of 0.6 μ.π and an average tilt angle of 35 ° in the film thickness direction. This film is not treated with acetic acid. It was transferred to a cellulose film using an ultraviolet-curable acryl-based adhesive. The same acrylic adhesive was applied to the liquid crystal polymer layer side for surface protection to obtain an optically anisotropic element C having a total thickness of about 100 m.

Example 1 (Preparation of elliptically polarizing plate A):

The optically anisotropic element A was immersed in a 2% aqueous hydration solution at room temperature for 5 minutes to carry out a curing treatment, washed in running water, and dried.

A cured optically anisotropic element A is continuously attached to one side of a polarizing element in which iodine is adsorbed on stretched polyvinyl alcohol using an acrylic adhesive such that the liquid crystal polymer layer is on the outside. I combined. An elliptically polarizing plate A of the present invention was produced by bonding a cured cellulose triacetate film to the other surface of the polarizing element. The total film thickness was about 200 m. Optical inspection of the elliptically polarizing plate A showed no damage such as spots or scratches on the liquid crystal polymer layer.

The optically anisotropic element A side of this elliptically polarizing plate A is attached to a glass plate via an ataryl adhesive, put in a constant temperature and humidity chamber at 60 ° C and 90% RH, and taken out after elapse of 500 hours. Observation revealed no abnormalities such as peeling or bubbles. Example 2 (Preparation of elliptically polarizing plate B):

An elliptically polarizing plate B was obtained in the same manner as in Example 1 except that the optically anisotropic element B was used instead of the optically anisotropic element A. The total film thickness was about 20 Om. Optical examination of this elliptically polarizing plate B showed no damage such as spots or scratches on the liquid crystal polymer layer.

The optically anisotropic element B side of the elliptically polarizing plate B is attached to a glass plate via an ataryl adhesive, put in a constant temperature and humidity chamber at 60 ° C and 90% RH, and taken out after elapse of 500 hours. Upon observation, no abnormalities such as peeling or foaming were observed. Example 3 (Preparation of elliptically polarizing plate C):

An elliptically polarizing plate C was obtained in the same manner as in Example 1 except that the optically anisotropic element C was used instead of the optically anisotropic element A. The total film thickness was about 200 / m. Optical inspection of the elliptically polarizing plate C showed no damage such as spots or scratches on the liquid crystal polymer layer.

The optically anisotropic element C side of the elliptically polarizing plate C is adhered to a glass plate via an acrylic adhesive, placed in a constant temperature and humidity chamber at 60 ° C and 90% RH, and taken out after a lapse of 500 hours. Upon observation, no abnormalities such as peeling or foaming were observed. Example 4:

Using this elliptically polarizing plate C, a liquid crystal display device was manufactured. The elliptically polarizing plate C is arranged on both sides of the optically anisotropic element C such that the side of the optically anisotropic element C is close to the driving liquid crystal cell, and the rubbing direction of the optically anisotropic element C and the orientation angle of the liquid crystal adjacent to the liquid crystal cell are 90 °. It was arranged so that it might become. The driving liquid crystal cell used ZL 1-47992 as the liquid crystal material, and the cell parameters were cell gap 4.8〃m, twist angle 90 ° (left twist), and pretilt angle 4 °. The viewing angle characteristics of this liquid crystal display device were wider than those without the optically anisotropic element C.

(Comparative example)

Preparation of optically anisotropic element D:

An alkyl-modified polyvinyl alcohol is applied to the oxidized 80-μm-thick cellulose triacetate film, dried, and then rubbed by the rubbing method described in the example of manufacturing optical anisotropic element A. An oriented film having an angle of 45 ° was obtained. The solution prepared in Preparation Example 2 of the liquid crystal polymer solution was applied to the above-mentioned rubbed cellulose triacetate long film, dried and then subjected to a heating alignment treatment to fix the alignment of the liquid crystal polymer layer. Δη d of this liquid crystal polymer layer was 0.8 m. An ultraviolet-curable acrylic adhesive was applied to the liquid crystal polymer layer side for surface protection to obtain an optically anisotropic element D having a total thickness of about 100 / m.

Preparation of optical anisotropic element E:

Optical anisotropic element E was obtained in exactly the same manner as in optical anisotropic element A, except that an acrylic adhesive for surface protection was not applied to the liquid crystal polymer layer.

Comparative Example 1 (Preparation of elliptically polarizing plate D):

Elliptically polarized light obtained by adhering an optically anisotropic element D to one side of the polarizing element so that the liquid crystal polymer layer is on the outside, and adhering a cellulose triacetate film to the other side in accordance with Example 1. Plate D was obtained. An acrylic adhesive was applied to the optically anisotropic element D side of the elliptically polarizing plate D and attached to a glass plate, and the same tests as in Examples 1 and 2 were performed. Peeling was observed between the polarizing element and the cellulose triacetate surface of the optically anisotropic element D.

Comparative Example 2 (Preparation of elliptically polarizing plate E): The optically anisotropic element E was immersed in a 2% aqueous hydroxide solution at room temperature for 5 minutes to carry out a curing treatment, washed in running water, and dried.

An ellipse in which the optically anisotropic element E is arranged on one side of the polarizing element so that the liquid crystal polymer layer is on the outside according to Example 1, and a cured cellulose triacetate film is adhered on the other side. A polarizing plate E was obtained. When an optical inspection of the elliptically polarizing plate E was performed, a number of spots and scratches which were considered to be caused by damage of the liquid crystal polymer layer were found.

Comparative Example 3 (Preparation of elliptically polarizing plate F):

Using a acryl-based adhesive, a cured cellulose triacetate film was attached to both sides of a polarizing element in which iodine was adsorbed to the stretched polyvinyl alcohol, to produce a polarizing plate. The elliptically polarizing plate F was manufactured by continuously bonding the liquid crystal polymer layer side of the optically anisotropic element B to this polarizing plate via an acrylic-based adhesive without subjecting it to a vulcanizing treatment. The elliptically polarizing plate F is as thick as about 300 xm and the winding thickness is large, so that the processing length in one operation must be shorter than that of the elliptically polarizing plates of Examples 1 and 2. Was not obtained. An acryl-based adhesive was applied to the optically anisotropic element B side of the elliptically polarizing plate F and attached to a glass plate, and the same test as in Example 2 was carried out. .5 mm peeling was observed.

Example 5 (Preparation of elliptically polarizing plate G):

While transporting a long PEEK film with a width of 65 mm and a thickness of 100 m, set a rubbing roll of 150 mm0 around which a rayon cloth is wound, and rotate it at high speed. Rubbing is performed continuously with a rubbing angle of 45. An oriented substrate film was obtained. Here, the rubbing angle is an angle clockwise from the MD direction when the rubbing surface is viewed from above. The solution obtained in Preparation Example 1 of the liquid crystal polymer solution was continuously applied and dried on the alignment substrate film using Daiko Yuichi to form an unoriented liquid crystal polymer layer. The liquid crystal polymer was aligned by heat treatment at 100 ° C. for 10 minutes, and then cooled to room temperature to fix the alignment. This liquid crystal polymer layer had a twisted nematic orientation, a twist angle of −230 ° and an And of 0.84 m. An ultraviolet-curable acryl-based adhesive is applied to the liquid crystal polymer layer on the PEEK film, bonded to a polyethylene terephthalate (PET) film, cured, separated from the PEEK film, and the liquid crystal polymer layer is PET. Transcribed on film Was. Next, apply the same acrylic adhesive to the surface of the liquid crystal polymer layer, bond it to the PET film, and cure it. PET film (separable substrate) Z-cured acrylic adhesive layer (translucent overcoat) (Coating layer) Z liquid crystal polymer layer No-cured ataryl adhesive layer (light-transmitting overcoat layer) A laminated film A composed of a ZPET film (separable substrate) was obtained.

A polarizing plate made by laminating 80 m thick cellulose triacetate (TAC) film with an acrylic adhesive on both sides of a polarizing element in which iodine is adsorbed to stretched polyvinyl alcohol. And the above laminated film A were continuously laminated via an acryl-based adhesive while continuously peeling the PET film on one side thereof, thereby producing an elliptically polarizing plate G. The total thickness of this elliptically polarizing plate is about 200 m: o

When the elliptically polarizing plate G was optically inspected, no damage such as spots or scratches was found on the liquid crystal polymer layer.

The PET film on the liquid crystal polymer layer side was peeled off from the elliptically polarizing plate G, and attached to a glass plate via an acryl-based adhesive to form a test piece. The test pieces were placed in a constant temperature oven at 80 ° C dry and a constant temperature / humidity oven at 60 ° C 90% RH.Each 500 hours later, they were removed and observed.No abnormality such as peeling or foaming was observed under both conditions. The power that has come.

Example 6 (Preparation of elliptically polarizing plate H):

A long PPS film having a width of 65 Omm and a thickness of 80 μm was subjected to rubbing treatment in the same manner as in Example 5 to obtain an oriented substrate film having a rubbing angle of 45 °. The solution prepared in Preparation Example 2 of the liquid crystal polymer solution was applied to the above-mentioned alignment substrate film, dried and then subjected to a heating alignment treatment to fix the alignment of the liquid crystal polymer layer. This liquid crystal polymer layer was in a nematic orientation, and had an And of 0. Hereinafter, a laminated film B was produced in the same manner as in Example 5, and an elliptically polarizing plate H was produced. The total film thickness of this elliptically polarizing plate was about 200 m.

Optical inspection of the elliptically polarizing plate H showed no damage or stains on the liquid crystal polymer layer.

Peel off the PET film on the liquid crystal polymer layer side from this elliptically polarizing plate H A test piece was attached to a glass plate via an adhesive. The test pieces were placed in a constant temperature oven at 80 ° C dry and a constant temperature / humidity oven at 60 ° C 90% RH.Each 500 hours later, they were taken out and observed.In both conditions, abnormalities such as peeling and foaming were observed. The power that was not recognized at all.

Example 7 (Preparation of elliptically polarizing plate I):

While conveying a long PEEK film with a width of 65 mm and a thickness of 100 m, set the rotation direction of the rubbing roll of 150 mm ø around which the rayon cloth is wound and the MD direction in parallel. Rubbing was performed continuously by rotating at high speed to obtain an oriented substrate film. The solution obtained in Liquid Crystal Polymer Solution Preparation Example 3 was coated on the above-mentioned oriented substrate film using a die coater, dried, and heated at 230 ° C for 10 minutes to align the liquid crystal polymer. And then immobilized. It was confirmed that the film had a nematic hybrid orientation with a film thickness of 0.6 (m) and an average tilt angle of 35 ° in the film thickness direction. A laminated film C was prepared in the same manner as in Example 5. Then, an elliptically polarizing plate I was manufactured, and the total thickness of the elliptically polarizing plate was about 200.

Optical inspection of this elliptically polarizing plate I revealed no damage such as spots or scratches on the liquid crystal polymer layer.

The PET film on the liquid crystal polymer layer side was peeled off from the elliptically polarizing plate I, and affixed to a glass plate via an acryl-based adhesive to form a test piece. The test specimens were placed in a constant temperature oven at 80 ° C dry and a constant temperature / humidity oven at 60 ° C 90% RH.After 500 hours, they were taken out and observed.In both conditions, abnormalities such as peeling and bubbles were observed. Was not recognized at all.

Example 8:

A liquid crystal display device was manufactured using the elliptically polarizing plate I. The elliptically polarizing plate I was arranged so that the liquid crystal polymer layer side was close to the driving liquid crystal cell, and was arranged such that the rubbing direction of the liquid crystal polymer layer and the orientation angle of the liquid crystal adjacent to the liquid HB cell were 90 °. . The driving liquid crystal cell used ZL 1-4792 as a liquid crystal material, and the cell parameters were a cell gap of 4.8 / m, a twist angle of 90 ° (left twist), and a pretilt angle of 4 °. The viewing angle characteristics of this liquid crystal display were wider than those without the liquid crystal polymer layer. Comparative Example 4 (Preparation of elliptically polarizing plate K):

A UV curable acrylic adhesive was applied to the liquid crystal polymer layer formed on the film obtained in Example 5 in accordance with Example 5 according to Example 5, and the thickness of the film was not reduced to 80 m. It was cured after bonding with a TAC film. Next, the PEEK film was peeled off, and the liquid crystal polymer layer was transferred onto the TAC film. Apply the same acrylic adhesive to the liquid crystal polymer layer side to protect the surface, and bond it to the PET film to form a PE TZ cured acrylic adhesive layer Z liquid crystal polymer layer Z cured acrylic adhesive layer AC A film was obtained.

An elliptically polarizing plate K was produced by continuously laminating the PET film from the laminated film to the polarizing plate of Example 5 via an acrylic adhesive while continuously removing the PET film. The total film thickness of this elliptically polarizing plate was as thick as about 300 μm.

An acryl-based adhesive was applied to the liquid crystal polymer layer side of the elliptically polarizing plate K, and was adhered to a glass plate to obtain a test piece. When the same tests as in Examples 5 and 6 were performed, a 0.4 mm skewing was observed on the test piece under the condition of 60 ° C and 90% RH after 500 hours.o

Comparative Example 5 (Preparation of elliptically polarizing plate L):

Without forming a surface protective layer on the liquid crystal polymer layer transferred on the PET film obtained in Example 5, the polarizer of Example 5 was continuously bonded to the polarizing plate via an acryl-based adhesive to form an ellipse. A polarizing plate L was produced. When an optical inspection was performed on the elliptically polarizing plate L, many spots and scratches were considered to be caused by damage to the liquid crystal polymer layer. An acryl-based adhesive was applied to the liquid crystal polymer layer side of the elliptical polarizing plate L and attached to a glass plate to obtain a test piece. When the same test as in Examples 5 and 6 was performed, fine pieces, wrinkles and cracks were recognized on the test piece under dry conditions at 800 after elapse of 500 hours.

〔The invention's effect〕

The elliptically polarizing plate of the present invention has a small total number of laminating layers constituting the elliptically polarizing plate and thus has a small total film thickness. Room can be processed. Furthermore, since the layer structure is simplified, there is an advantage that no peeling or bubbles are generated at the interface in the accelerated durability test. In the laminating process, it can be laminated in the form of a long film. The bonding process can be streamlined compared to the conventional method, and there is no damage to the liquid crystal polymer layer.

Claims

The scope of the claims

1. An elliptically polarizing plate having a liquid crystal polymer layer and a polarizing element, and a polarizing element disposed between the optically anisotropic element having the liquid crystal polymer layer oriented on the triacetate cell-film and the light-transmitting protective film. An elliptically polarizing plate, characterized in that the optically anisotropic element is subjected to a vulcanization treatment.

2. The elliptically polarizing plate according to claim 1, wherein a translucent overcoat layer is provided on a surface of the liquid crystal polymer layer.

3. The elliptically polarizing plate according to claim 2, wherein the translucent overcoat layer is made of an ataryl resin.

4. The elliptically polarizing plate according to any one of claims 1 to 3, wherein the liquid crystal polymer layer is composed of liquid crystal molecules having optically positive uniaxiality.

5. The ellipse according to any one of claims 1 to 4, wherein the direction of orientation of the liquid crystal polymer near one of the two surfaces of the liquid crystal polymer layer is not parallel to the MD direction. Polarizer.

6. The elliptically polarizing plate according to any one of claims 1 to 5, wherein the optically anisotropic element, the translucent protective film, and the polarizing element are in the form of a long film.

7. After forming a liquid crystal polymer layer on the cellulose triacetate film, an optically anisotropic element is manufactured by providing a translucent overcoat layer on the surface of the liquid crystal polymer layer, and then the optically anisotropic element is manufactured. The device is subjected to a vulcanization treatment, and thereafter, a polarizing film is bonded via an adhesive layer so as to be sandwiched between the optically anisotropic device and the light-transmitting protective film. Or the method for producing an elliptically polarizing plate according to item 1.

8. A liquid crystal display device, wherein the elliptically polarizing plate according to any one of claims 1 to 5 is disposed on at least one surface of a liquid crystal cell.

9. A method for producing an elliptically polarizing plate having a liquid crystal polymer layer and a polarizing element, wherein the liquid crystal polymer layer formed on a substrate that is separable from the polarizing element is bonded via an adhesive layer. A method for producing an elliptically polarizing plate.

10. The method according to claim 9, wherein the surface of the liquid crystal polymer layer formed on the releasable substrate is protected by a translucent overcoat layer.

11. The translucent overcoat layer is made of an acrylic resin. 10. The method according to 10.

12. The method according to any one of claims 9 to 11, wherein the liquid crystal polymer layer is composed of optically positive uniaxial liquid crystal molecules.

13. The liquid crystal polymer layer according to any one of claims 9 to 12, wherein the orientation direction of the liquid crystal polymer near one of the two surfaces of the liquid crystal polymer layer is not parallel to the MD direction. Method.

14. The method according to any one of claims 9 to 13, wherein the liquid crystal polymer layer supported on the releasable substrate is in the form of a long film, and the bonding is performed continuously.

15. A liquid crystal display device comprising an elliptically polarizing plate manufactured by the method according to any one of claims 9 to 14 on at least one surface of a liquid crystal cell.