JP2001272541A - Polarizing plate with optical compensating film and liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polarizing plate with an optical compensating film and a liquid crystal display device improved in display unevenness by making creep at 50 deg.C of adhesive layers A2 and 12 into 70 μm or more, in the polarizing plate with the optical compensating film containing the polarizing plates 1 and 11, the adhesive layers A2 and 12, the optical compensating films 3 and 13, and the adhesive layers B4 and 14. SOLUTION: The adhesive layer A is vertically stood to the mirror finish surface of the stainless steel (SUS304) plate, the area of 10 mm long and 10 mm wide is stuck, the 200 g load is imposed under 50 deg.C ambient atmosphere, and the creep of 1 hour after is measured. The creep of the adhesive layer B is preferably under 70 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polarizing plate with an optical compensation film and a liquid crystal display device used for a liquid crystal display device (hereinafter sometimes abbreviated as LCD) with improved display unevenness.

[0002]

2. Description of the Related Art In an STN-LCD, an optical compensation film is used to perform monochrome display and color display. In order to achieve a wide viewing angle, a thin film transistor (TFT) -LCD uses an optical compensation film in which a polymer is uniaxially or biaxially stretched or an optical compensation film in which a liquid crystal polymer is oriented.

A polarizing plate used for a display device (especially LCD) is, for example, a polyvinyl alcohol film (hereinafter referred to as P
Sometimes abbreviated as VA film. ), Iodine or dichroic dye, a dyeing step of dyeing with a dichroic dye, a cross-linking step of cross-linking with boric acid or borax, and a stretching step of uniaxial stretching (each step of dyeing, crosslinking, stretching, The steps need not be performed separately and may be performed at the same time, and the order of each step is not particularly specified.), Then, dried, and then triacetylcellulose film (hereinafter sometimes abbreviated as TAC film). It is manufactured by laminating with such a protective layer.

When the LCD panel is turned on, heat generated from a backlight or the like heats the polarizing plate and the optical compensation film to 40 to 60 ° C., and the polarizing plate and the optical compensation film expand due to linear expansion. The polarizing plate and the optical compensation film are laminated via an adhesive, but the dimensional change is larger in the polarizing plate. For this reason, there is a problem that stress due to a difference in dimensional change between the polarizing plate and the optical compensation film is applied to the optical compensation film side, and display unevenness of the LCD panel occurs.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polarizing plate with an optical compensation film and a liquid crystal display device for use in an LCD with improved display unevenness in order to solve the above-mentioned conventional problems. Things.

[0006]

In order to achieve the above object, a polarizing plate with an optical compensation film according to the present invention comprises a polarizing plate, an adhesive layer A, an optical compensation film and a polarizing plate with an optical compensation film, comprising an adhesive layer B. A pressure-sensitive adhesive layer A on a mirror-finished surface of a stainless steel (SUS304) plate.
An area of 0 mm and a width of 10 mm is attached, a load of 200 g is applied in an atmosphere of 50 ° C., and the creep amount of the pressure-sensitive adhesive layer A after one hour is 70 μm or more.

In the polarizing plate with the optical compensation film, it is preferable that the creep amount of the pressure-sensitive adhesive layer B is less than 70 μm in the measurement according to the above-mentioned measuring method.

In the polarizing plate with an optical compensation film, the optical compensation film preferably comprises a triacetyl cellulose film and a layer in which liquid crystals are oriented.

Next, a liquid crystal display device according to the present invention is characterized in that the polarizing plate with the optical compensation film described above is provided on at least one side of a liquid crystal cell.

According to the polarizing plate with the optical compensation film of the present invention, the creep amount of the pressure-sensitive adhesive layer A is set to 70 μm or more, so that the dimensional change of the polarizing plate and the optical compensation film caused by heat generated from the backlight or the like. Can be alleviated due to the difference between the two.

Further, by setting the creep amount of the pressure-sensitive adhesive layer B in an atmosphere of 50 ° C. to less than 70 μm, it is possible to prevent the optical compensation film from being deformed by the stress generated due to the dimensional change of the polarizing plate and causing a phase difference. This can prevent display unevenness of the LCD panel.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG.
Is an embodiment of the polarizing plate with an optical compensation film of the present invention. As shown in FIG. 1, the basic configuration of the polarizing plate according to the present invention is such that the polarizing plate 1, the pressure-sensitive adhesive layer A2, the optical compensation film 3, and the pressure-sensitive adhesive layer B4 are bonded to the liquid crystal panel 5.
And / or polarizing plate 11 on the other surface of liquid crystal panel 5.
Then, the pressure-sensitive adhesive layer A12, the optical compensation film 13, and the pressure-sensitive adhesive layer B14 are bonded to the liquid crystal panel 5. Adhesive layer A
2 and 12 are, for example, an acrylic pressure-sensitive adhesive having a thickness of 10 μm to 4 μm.
It was applied in a range of 0 μm. Adhesive layer B4,1
4 is, for example, an acrylic adhesive having a thickness of 10 μm to 40 μm.
It was applied in the range of. Optical compensation film 3, 1
No. 3 includes, for example, WV A02B manufactured by Fuji Photo Film Co., Ltd.

The basic structure of the polarizing plate used in the present invention is as follows.
A suitable adhesive layer on one or both sides of a polarizer made of a dichroic substance-containing polyvinyl alcohol-based polarizing film,
For example, it is formed by bonding a transparent protective film serving as a protective layer via an adhesive layer made of a vinyl alcohol-based polymer or the like.

As a polarizer (polarizing film), for example, a dichroic substance made of iodine or a dichroic dye or the like may be applied to a film made of an appropriate vinyl alcohol-based polymer according to the related art such as polyvinyl alcohol or partially formalized polyvinyl alcohol. , A suitable treatment such as a stretching treatment, a cross-linking treatment, or the like is performed in an appropriate order or manner, and an appropriate material that transmits linearly polarized light when natural light is incident thereon can be used. Above all, those having excellent light transmittance and degree of polarization are preferable.

An appropriate transparent film can be used as a protective film material serving as a transparent protective layer provided on one side or both sides of a polarizer (polarizing film). As an example of the polymer, an acetate resin such as triacetylcellulose is generally used, but is not limited thereto.

A transparent protective film that can be particularly preferably used in view of polarization characteristics and durability is a triacetyl cellulose film whose surface is saponified with an alkali or the like. When transparent protective films are provided on both sides of the polarizing film, transparent protective films made of different polymers or the like may be used on both sides.

The transparent protective film used for the protective layer includes:
As long as the object of the present invention is not impaired, a hard coat treatment, an anti-reflection treatment, a treatment for preventing sticking, diffusion or anti-glare, or the like may be performed. The hard coat treatment is performed for the purpose of preventing the surface of the polarizing plate from being scratched. For example, a hardened film excellent in hardness and slipperiness by an appropriate ultraviolet curable resin such as a silicone resin is coated on the surface of the transparent protective film. Can be formed.

On the other hand, the antireflection treatment is performed for the purpose of preventing reflection of external light on the surface of the polarizing plate, and can be achieved by forming an antireflection film or the like according to the related art. In addition, sticking prevention is for the purpose of preventing adhesion with the adjacent layer,
The anti-glare treatment is performed for the purpose of preventing external light from being reflected on the surface of the polarizing plate and hindering the visibility of light transmitted through the polarizing plate, and is, for example, a roughening method using a sandblasting method or an embossing method. The transparent protective film can be formed by giving a fine uneven structure to the surface of the transparent protective film by an appropriate method such as a method of mixing transparent fine particles.

Examples of the transparent fine particles include silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, and antimony oxide having an average particle size of 0.5 to 20 μm. Fine particles may be used, or organic fine particles composed of crosslinked or uncrosslinked polymer particles or the like may be used. The use amount of the transparent fine particles is generally 2 to 70 parts by weight, particularly 5 to 50 parts by weight, per 100 parts by weight of the transparent resin.

The anti-glare layer containing the transparent fine particles can be provided as the transparent protective layer itself or as a coating layer on the surface of the transparent protective layer. The anti-glare layer may also serve as a diffusion layer (such as a viewing angle compensation function) for diffusing light transmitted through the polarizing plate to increase the viewing angle.
The above-described anti-reflection layer, anti-sticking layer, diffusion layer, anti-glare layer, and the like can be provided as an optical layer made of a sheet or the like provided with these layers, separately from the transparent protective layer.

In the present invention, the bonding treatment between the polarizer (polarizing film) and the transparent protective film as the protective layer is not particularly limited. For example, an adhesive comprising a vinyl alcohol-based polymer or boric acid Or borax,
It can be carried out via an adhesive comprising at least a water-soluble cross-linking agent of a vinyl alcohol-based polymer such as glutaraldehyde, melamine, and oxalic acid. Such an adhesive layer can be formed as a coating and drying layer of an aqueous solution, but when preparing the aqueous solution, if necessary, other additives,
A catalyst such as an acid can also be blended.

The polarizing plate according to the present invention can be used as an optical member laminated with another optical layer in practical use.
The optical layer is not particularly limited. For example, a reflector, a transflector, a retardation plate (including a λ plate such as a 波長 wavelength plate and a 板 wavelength plate), a viewing angle compensation film, and a brightness enhancement film One or two or more appropriate optical layers that may be used for forming a liquid crystal display device or the like can be used. In particular, a polarizing plate including the polarizer of the present invention and the protective layer described above includes: Further, a reflection plate or a reflection type polarizing plate or a semi-transmission reflection type polarizing plate in which a transflective reflection plate is laminated, a retardation plate is further laminated on the above-mentioned polarizing plate comprising the polarizer of the present invention and a protective layer. An elliptical or circular polarizer, a polarizer comprising the polarizer and the protective layer of the present invention described above, and a polarizing plate further laminated with a viewing angle compensation film, or the polarizer and the protective layer of the present invention described above. Brightness enhancement film on the polarizing plate Polarizing plates are preferred.

The reflection plate will be described. The reflection plate is provided on a polarizing plate to form a reflection-type polarizing plate. The reflection-type polarizing plate is usually provided on the back side of a liquid crystal cell and can be visually recognized. It is possible to form a liquid crystal display device of the type that reflects and reflects incident light from the side (display side), and has the advantage that the built-in light source such as a backlight can be omitted and the thickness of the liquid crystal display device can be easily reduced. .

The reflective polarizing plate can be formed by an appropriate method such as a method in which a reflective layer made of metal or the like is provided on one side of the polarizing plate via the transparent protective film or the like as necessary. Incidentally, a specific example thereof includes a transparent protective film which has been subjected to a mat treatment as required, and a reflective layer formed by attaching a foil or a vapor-deposited film made of a reflective metal such as aluminum on one surface.

Further, there may be mentioned a reflection type polarizing plate having a reflection layer reflecting the fine unevenness on the transparent protective film having a fine unevenness on the surface containing fine particles. The reflective layer with a fine surface irregularity structure diffuses the incident light by irregular reflection to prevent directivity and glare,
It has an advantage that light and dark unevenness can be suppressed. The formation of the reflective layer of the fine uneven structure reflecting the fine uneven structure on the surface of the transparent protective film is performed by, for example, making the metal transparent by an appropriate method such as an evaporation method such as a vacuum evaporation method, an ion plating method, or a sputtering method, or a plating method. It can be performed by a method of directly attaching to the surface of the protective film.

The reflecting plate can be used as a reflecting sheet in which a reflecting layer is provided on an appropriate film conforming to the transparent protective film, instead of the method of directly attaching the reflective plate to the transparent protective film described above. . Since the reflection layer of the reflection plate is usually made of a metal, the use form in which the reflection surface is covered with a film, a polarizing plate, or the like is intended to prevent a decrease in the reflectance due to oxidation and to maintain the initial reflectance for a long time. It is preferable from the viewpoint of avoiding separately providing a protective layer.

The transflective polarizing plate can be obtained by forming the reflective layer as a transflective reflective layer such as a half mirror that reflects and transmits light. A transflective polarizing plate is usually provided on the back side of a liquid crystal cell. When a liquid crystal display device or the like is used in a relatively bright atmosphere, an image is displayed by reflecting incident light from the viewing side (display side). In a relatively dark atmosphere, it is possible to form a liquid crystal display device that displays an image using a built-in light source such as a backlight built in the back side of a transflective polarizing plate. That is, the transflective polarizing plate can save energy for use of a light source such as a backlight in a bright atmosphere, and can be used for forming a liquid crystal display device or the like that can be used with a built-in light source even in a relatively dark atmosphere. Useful.

Next, an elliptic or circular polarizing plate in which a retardation plate is further laminated on the above-described polarizing plate comprising the polarizer of the present invention and a protective layer will be described.

When changing linearly polarized light to elliptical or circularly polarized light, or changing elliptical or circularly polarized light to linearly polarized light, or changing the polarization direction of linearly polarized light, a retardation plate or the like is used. Is a so-called quarter-wave plate (also referred to as a λ / 4 plate) as a retardation plate that changes into elliptical or circularly polarized light, or changes elliptical or circularly polarized light into linearly polarized light.
Is used. A half-wave plate (also called a λ / 2 plate)
It is usually used to change the polarization direction of linearly polarized light.

The elliptically polarizing plate is effectively used for compensating for coloring (blue or yellow) caused by the birefringence of the liquid crystal layer of the STN liquid crystal display device to make a monochrome display without the coloring. Further, the one in which the three-dimensional refractive index is controlled can also compensate (prevent) coloring that occurs when the screen of the liquid crystal display device is viewed from an oblique direction, and is preferable. The circularly polarizing plate is effectively used, for example, when adjusting the color tone of an image of a reflection type liquid crystal display device for displaying an image in color, and also has an antireflection function.

Incidentally, as a specific example of the retardation plate,
Birefringent film, liquid crystal polymer alignment film, liquid crystal polymer alignment film obtained by stretching a film made of a suitable polymer such as polycarbonate, polyvinyl alcohol, polystyrene, polymethyl methacrylate, polypropylene and other polyolefins, polyarylate and polyamide. One in which the layer is supported by a film is exemplified. Examples of the obliquely oriented film include, for example, a film obtained by bonding a heat shrinkable film to a polymer film and subjecting the polymer film to a stretching treatment and / or a shrinking treatment under the action of the shrinkage force caused by heating, or a film obtained by obliquely aligning a liquid crystal polymer. Is raised.

Next, a polarizing plate in which a viewing angle compensation film is further laminated on the above-mentioned polarizing plate comprising the polarizer of the present invention and a protective layer will be described.

The viewing angle compensation film is a film for widening the viewing angle so that an image can be seen relatively clearly even when the screen of the liquid crystal display device is viewed not in a direction perpendicular to the screen but in a slightly oblique direction.

As such a viewing angle compensating film, a film obtained by coating a discotic liquid crystal on a triacetyl cellulose film or the like, or a retardation plate is used. Whereas a polymer film having a birefringence in which a normal retardation plate is uniaxially stretched in the plane direction is used, a retardation plate used as a viewing angle compensation film is a birefringent film which is biaxially stretched in the plane direction. Or a bidirectionally stretched film such as an obliquely oriented polymer film which is uniaxially stretched in the plane direction and stretched in the thickness direction and has a controlled refractive index in the thickness direction. As described above, for example, as described above, the heat-shrinkable film is adhered to the polymer film, and the polymer film is stretched or / and shrunk under the action of the heat-induced shrinkage force. And the like. As the raw material polymer for the retardation plate, the same polymer as the polymer described for the retardation plate is used.

A polarizing plate obtained by laminating a brightness enhancement film on the polarizing plate comprising the polarizer of the present invention and the protective layer described above,
Usually, it is provided and used on the back side of the liquid crystal cell. The brightness enhancement film reflects linearly polarized light having a predetermined polarization axis or circularly polarized light having a predetermined direction when natural light is incident due to reflection from a backlight or a back side of a liquid crystal display device, and has a property of transmitting other light. A polarizing plate obtained by laminating a brightness enhancement film with a polarizing plate comprising the above-described polarizer and a protective layer, while allowing light from a light source such as a backlight to enter to obtain transmitted light of a predetermined polarization state and the predetermined polarization state. Other light is reflected without transmitting. The light reflected on the surface of the brightness enhancement film is further inverted via a reflection layer or the like provided on the rear side thereof and re-incident on the brightness enhancement plate, and a part or all of the light is transmitted as light of a predetermined polarization state to achieve brightness. The brightness can be improved by increasing the amount of light transmitted through the enhancement film and by supplying polarized light that is hardly absorbed by the polarizer to increase the amount of light that can be used for liquid crystal image display and the like. In other words, when light is incident through a polarizer from the back side of a liquid crystal cell with a backlight or the like without using a brightness enhancement film, light having a polarization direction that does not coincide with the polarization axis of the polarizer is hardly generated. Is absorbed by
Does not pass through the polarizer. That is, although it differs depending on the characteristics of the polarizer used, about 50% of the light is absorbed by the polarizer, and accordingly, the amount of light available for liquid crystal image display and the like decreases, and the image becomes darker. The brightness enhancement film is such that light having a polarization direction that is absorbed by the polarizer is once reflected by the brightness enhancement film without being incident on the polarizer, and further inverted through a reflection layer or the like provided on the rear side. Repeatedly re-entering the brightness enhancement plate, the brightness enhancement film transmits the polarized light whose polarization direction has been changed so that the polarization direction of the light reflected and inverted between the two can pass through the polarizer. Since the light is supplied to the child, light from a backlight or the like can be efficiently used for displaying an image on the liquid crystal display device, and the screen can be brightened.

As the above-mentioned brightness enhancing film, for example, a linearly polarized light having a predetermined polarization axis is transmitted and other light is reflected, such as a multilayer thin film of a dielectric or a multilayer laminate of thin films having different refractive index anisotropy. The cholesteric liquid crystal layer, especially the cholesteric liquid crystal polymer oriented film or the one that supports the oriented liquid crystal layer on a film substrate, reflects either left-handed or right-handed circularly polarized light. Other appropriate light, such as one exhibiting a characteristic of transmitting other light, may be used.

Therefore, in the brightness enhancement film of the type that transmits linearly polarized light having a predetermined polarization axis, the transmitted light is incident on the polarization plate with the polarization axis aligned as it is, thereby suppressing the absorption loss by the polarization plate and efficiently. Can be transmitted. On the other hand, a brightness enhancement film that transmits circularly polarized light, such as a cholesteric liquid crystal layer, can be directly incident on a polarizer.However, rather than suppressing absorption loss, the transmitted circularly polarized light is converted to linearly polarized light through a retardation plate. It is preferable to make the light incident on the polarizing plate. Incidentally, by using a quarter-wave plate as the retardation plate, circularly polarized light can be converted into linearly polarized light.

A retardation plate that functions as a quarter-wave plate in a wide wavelength range such as a visible light region is, for example, a retardation layer that functions as a quarter-wave plate for monochromatic light such as light having a wavelength of 550 nm. , For example, a method of superimposing a retardation layer functioning as a half-wave plate with the retardation layer exhibiting the above retardation characteristic. Therefore, the retardation plate disposed between the polarizing plate and the brightness enhancement film may be composed of one or more retardation layers.

The cholesteric liquid crystal layer also has a structure in which two or three or more cholesteric liquid crystal layers having different reflection wavelengths are overlapped with each other to reflect circularly polarized light in a wide wavelength range such as a visible light region. Thus, it is possible to obtain circularly polarized light transmitted in a wide wavelength range.

The polarizing plate of the present invention may be formed by laminating a polarizing plate and two or three or more optical layers as in the above-mentioned polarized light separating type polarizing plate. Therefore, a reflective elliptically polarizing plate or a transflective elliptically polarizing plate obtained by combining the above-mentioned reflective polarizing plate, semi-transmissive polarizing plate and retardation plate may be used. An optical member in which two or three or more optical layers are laminated,
Although it can be formed by a method of sequentially laminating layers sequentially in the manufacturing process of a liquid crystal display device or the like, those which are preliminarily laminated as an optical member are excellent in stability of quality and workability of assembly, etc. There is an advantage that the manufacturing efficiency of the device or the like can be improved. For the lamination, an appropriate adhesive means such as an adhesive layer can be used.

The polarizing plate or the optical member according to the present invention may be provided with an adhesive layer for bonding to another member such as a liquid crystal cell. The pressure-sensitive adhesive layer can be formed with an appropriate pressure-sensitive adhesive, such as an acrylic resin, according to the related art. Above all, from the viewpoint of preventing foaming and peeling phenomena due to moisture absorption, deterioration of optical characteristics due to difference in thermal expansion, prevention of liquid crystal cell warpage, and formation of a high quality and durable liquid crystal display device, the moisture absorption rate It is preferable that the pressure-sensitive adhesive layer has low heat resistance and excellent heat resistance. In addition, an adhesive layer or the like which contains fine particles and exhibits light diffusibility can be used. The adhesive layer may be provided on a necessary surface if necessary.For example, if mention is made of the protective layer of the polarizing plate comprising the polarizer and the protective layer of the present invention, if necessary, one or both surfaces of the protective layer May be provided with an adhesive layer.

When the adhesive layer provided on the polarizing plate or the optical member is exposed on the surface, it is preferable to temporarily cover the adhesive layer with a separator until practical use of the adhesive layer for the purpose of preventing contamination and the like. The separator is formed by a method of providing a release coat with a suitable release agent such as a silicone-based or long-chain alkyl-based, fluorine-based or molybdenum sulfide as necessary, on a suitable thin leaf according to the transparent protective film or the like. be able to.

Each layer such as a polarizing film, a transparent protective film, an optical layer and an adhesive layer forming the above-mentioned polarizing plate or optical member is made of, for example, a salicylate compound, a benzophenone compound, a benzotriazole compound or a cyanoacrylate compound. Alternatively, a material having an ultraviolet absorbing ability by an appropriate method such as a method of treating with an ultraviolet absorbing agent such as a nickel complex compound may be used.

The polarizing plate according to the present invention can be preferably used for forming various devices such as a liquid crystal display device. The liquid crystal display device is a transmission type or reflection type in which the polarizing plate according to the present invention is disposed on one side or both sides of a liquid crystal cell, or a transmission type or a reflection type.
It can be formed as a device having an appropriate structure according to the related art such as a dual-purpose type. Therefore, the liquid crystal cell forming the liquid crystal display device is arbitrary, and may be an appropriate type such as an active matrix driving type represented by a thin film transistor type, a simple matrix driving type represented by a twisted nematic type or a super twisted nematic type, and the like. A liquid crystal cell of a type may be used.

When polarizing plates and optical members are provided on both sides of the liquid crystal cell, they may be the same or different. Further, in forming the liquid crystal display device, one or more layers of appropriate components such as a prism array sheet, a lens array sheet, a light diffusing plate, and a backlight can be arranged at appropriate positions.

[0046]

The present invention will be described more specifically with reference to the following examples.

(Measurement Method of Creep Amount) As shown in FIGS. 2A and 2B, the pressure-sensitive adhesive layer 21 of the base material 22 of the present invention is adhered to the mirror-finished surface of the stainless steel (SUS304) plate 20. I attached. The paste area is 10 mm for vertical a and 1 for horizontal b.
0 mm. The initial bonding pressure was 5 kg / cm ² . afterwards,
Except for the adhesive pressure, a load of 200 g W in an atmosphere of 50 ° C.
And the amount of creep of the pressure-sensitive adhesive layer A after 1 hour was measured.

(Evaluation Method of Liquid Crystal Panel) The LCD panels obtained in the following Examples and Comparative Examples were turned on to make the entire surface black, and after standing for 1 hour, the presence or absence of display unevenness was visually observed at five levels. Larger numbers indicate less unevenness. The evaluation was performed by five persons, and the average was evaluated excluding the highest point and the lowest point.

Example 1 A polyvinyl alcohol film having a thickness of 80 μm was immersed in a dyeing bath (30 ° C.) containing iodine and potassium iodide, dyed and stretched 5 times, and then dried. Next, a triacetylcellulose film having a thickness of 80 μm as a protective film was adhered to both sides of the polyvinyl alcohol film after the iodine staining with an adhesive to obtain a polarizing plate.

As the optical compensation film, “WV A02B” manufactured by Fuji Photo Film Co., Ltd. was used. This is a film comprising a triacetyl cellulose film and a layer in which liquid crystals are oriented.

These are cut to a predetermined shaft angle and size,
As shown in FIG. 1, both sides of the TFT-LCD cell were bonded via adhesives A and B.

Adhesive A is made of isooctyl acrylate 100
Parts by weight, 0.1 parts by weight of 2-hydroxyethyl acrylate, and 0.5 parts by weight of azobisisobutyronitrile were dissolved in ethyl acetate to a monomer concentration of 50% by weight.
0.2 parts by weight of an isocyanate-based crosslinking agent (trade name: Coronate L, manufactured by Nippon Polyurethane Industry Co., Ltd.) was added to 100 parts by weight of the solid content of the polymer solution polymerized at 0 ° C. for 8 hours to form an adhesive syrup. 25 thickness after drying
It was applied to a thickness of μm. The amount of creep at 50 ° C. was 90 μm.

Adhesive B was prepared by dissolving 100 parts by weight of butyl acrylate, 5 parts by weight of acrylic acid, and 0.5 parts by weight of benzoyl peroxide in ethyl acetate so as to have a monomer concentration of 50% by weight. 1 part by weight of an isocyanate-based crosslinking agent (trade name: Coronate L, manufactured by Nippon Polyurethane Industry Co., Ltd.) was added to 100 parts by weight of the solid content of the polymerized polymer solution to obtain an adhesive syrup, and the thickness after drying was 25 μm. It applied so that it might become. The amount of creep at 50 ° C. was 60 μm.

The evaluation results of the obtained liquid crystal panel are shown in Table 1 below.

Example 2 The same procedure as in Example 1 was carried out except that the pressure-sensitive adhesives A and B each used an acrylic pressure-sensitive adhesive having a creep amount of 90 μm at 50 ° C. (pressure-sensitive adhesive A used in Example 1).

Comparative Example 1 The same procedure as in Example 1 was carried out except that the pressure-sensitive adhesives A and B each used an acrylic pressure-sensitive adhesive having a creep amount of 60 μm at 50 ° C. (pressure-sensitive adhesive B used in Example 1).

(Comparative Example 2) An acrylic pressure-sensitive adhesive (pressure-sensitive adhesive B used in Example 1) having a creep amount of 60 μm at 50 ° C. was used as the pressure-sensitive adhesive A, and a pressure-sensitive adhesive having a creep amount of 90 μm at 50 ° C. was used as the pressure-sensitive adhesive B. Example 1 was repeated except that an acrylic pressure-sensitive adhesive (pressure-sensitive adhesive A used in Example 1) was used.

The above results are shown in Table 1 below.

[0059]

[Table 1]

As is clear from Table 1, the pressure-sensitive adhesive A 50
When the creep amount at 70 ° C. was 70 μm or more, the evaluation result was 3.6 or more, and it was confirmed that display unevenness was reduced. Further, when the creep amount at 50 ° C. of the pressure-sensitive adhesive A is 70 μm or more and the creep amount at 50 ° C. of the pressure-sensitive adhesive B is less than 70 μm, the evaluation result is 4.7 or more, and it can be confirmed that the display unevenness is further reduced. Was.

[0061]

The present invention relates to a polarizing plate with an optical compensation film comprising a polarizing plate, an adhesive layer A, an optical compensation film and an adhesive layer B, wherein the creep amount of the adhesive layer A at 50 ° C. is 70 μm or more. By doing so, it is possible to provide a polarizing plate with an optical compensation film and a liquid crystal display device with improved display unevenness.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of one embodiment of a polarizing plate with an optical compensation film of the present invention.

FIGS. 2A and 2B are explanatory diagrams showing a method for measuring the amount of creep according to the present invention.

[Explanation of symbols]

 Reference Signs List 1,11 Polarizing plate 2,12 Pressure-sensitive adhesive layer A 3,13 Optical compensation film 4,14 Pressure-sensitive adhesive layer B 5 Liquid crystal panel 20 Stainless steel (SUS304) 21 Pressure-sensitive adhesive layer 22 Base material of the present invention

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor: Nei Takahashi 1-1-2 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation (72) Inventor Seiichi Kusumoto 1-1-2 Shimohozumi, Ibaraki-shi, Osaka Inside Nitto Denko (72) Inventor Yoichiro Sugino 1-1-2 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation (72) Inventor Takuya Matsunaga 1-1-2 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Inside (72) Inventor Senri Yoshikawa 1-1-2 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Co., Ltd. (72) Inventor Masamori Masada 1-2-1, Shimohozumi, Ibaraki-shi, Osaka Nitto Denko F term (for reference) 2H049 BA02 BA03 BA04 BA06 BA27 BA42 BB03 BB33 BB43 BB49 BB51 BC03 2H091 FA08X FA08Z FA11X FA11Z FA12X FA12Z FB02 FB12 FD06 FD16 LA16 LA18

Claims (4)

[Claims] 1. A polarizing plate with an optical compensation film comprising a polarizing plate, a pressure-sensitive adhesive layer A, an optical compensation film and a pressure-sensitive adhesive layer B, wherein the pressure-sensitive adhesive layer A is formed on a mirror-finished surface of a stainless steel (SUS304) plate. A polarizing plate with an optical compensation film, wherein an area of 10 mm in length and 10 mm in width is attached, a load of 200 g is applied in an atmosphere of 50 ° C., and the creep amount of the pressure-sensitive adhesive layer A after 1 hour is 70 μm or more. . 2. The polarizing plate with an optical compensation film according to claim 1, wherein the amount of creep of the pressure-sensitive adhesive layer B is less than 70 μm in the measurement according to the measuring method according to claim 1. 3. The polarizing plate with an optical compensation film according to claim 1, wherein the optical compensation film comprises a triacetyl cellulose film and a layer in which liquid crystals are oriented. 4. A liquid crystal display device comprising the polarizing plate with the optical compensation film according to claim 1 on at least one side of a liquid crystal cell.