TWI477827B - Polarizing plate, liquid crystal panel using such polarizing plate, and liquid crystal display device - Google Patents

Description

Polarizing plate, liquid crystal panel using the same, and liquid crystal display device

The present invention relates to a polarizing plate comprising a resin film laminated on one or both sides of a polarizing film, a liquid crystal panel using the polarizing plate, and a liquid crystal display device.

The liquid crystal display device is used as a thin display device such as a liquid crystal television, a liquid crystal screen, or a personal computer, and its use is rapidly expanding. In particular, the market for LCD TVs has significantly expanded, and the requirements for cost reduction are also very high.

Generally, a liquid crystal display device is composed of a backlight composed of a cold cathode tube or an LED (light emitting diode), a light diffusing plate, one or a plurality of light diffusing sheets, a back side polarizing plate, and a liquid crystal cell ( Liquid crystal cells) and visual side polarizers. A concentrating sheet may be further disposed between the backlight and the back side polarizing plate.

In order to reduce the thickness of the liquid crystal television, the thickness of the liquid crystal television used for the large-screen LCD TV is reduced, and the thickness of the liquid crystal television is reduced, and the number of members to be used and the number of members are reduced. For such a demand, it is known to reduce the number of parts by omitting one or a plurality of light diffusion sheets by imparting light diffusibility to the back side polarizing plate disposed between the liquid crystal cell and the backlight (for example, JPH11-183712) -A, JP2000-75133-A, JP2000-75134-A, JP2000-75134-A, JP2000-75134-A, and JP2000-75134-A).

For example, JP2000-75136-A discloses a light diffusion layer having a single-sided or two-sided surface adhered to a polarizing plate, the outer surface of which has a fine uneven structure having a center line average roughness of 0.3 μm or more, and has a pencil. In the light-diffusing polarizing plate having a surface hardness of not less than the hardness of H, it is described that by controlling the surface hardness of the light-diffusing layer to be equal to or less than H, it is possible to prevent damage of an optical member such as a condensing sheet which is disposed on the polarizing plate.

However, the conventional light diffusing polarizing plate used as the back side polarizing plate does not take into consideration the scratch resistance of the surface of the polarizing plate itself, and the light diffusing plate, the light diffusing sheet, and the light diffusing sheet are formed on the light diffusing polarizing plate in the liquid crystal display device. When the optical members such as the condensing sheet are placed one on another, the surface of the light diffusing polarizing plate is damaged by contact with the optical member, which adversely affects the quality of the image of the liquid crystal display device.

Therefore, an object of the present invention is to provide a polarizing plate which can obtain a high-quality image when a liquid crystal display device is manufactured, and in particular, a back side polarizing plate which is disposed between a liquid crystal cell and a backlight. Further, another object of the present invention is to provide a liquid crystal panel and a liquid crystal display device using the polarizing plate.

The present invention provides a polarizing plate for a back side, which is provided with a polarizing film and a layer composed of a polyvinyl alcohol-based resin film which is uniaxially stretched with a dichroic dye such as iodine or a dichroic dye. A resin film that is bonded to at least one surface of the polarizing film is disposed between the liquid crystal cell included in the liquid crystal display device and the backlight. Here, the hardness of the surface (outer surface) of the resin film opposite to the side opposite to the polarizing film (hereinafter also referred to as steel wool hardness) is such that the surface is made of steel wool at a load of 250 g/cm ² and stroke. The number of flaws when rubbing back and forth 10 times under the condition of a width of 5 cm and a speed of 50 times back/minute was indicated to be 10 or less. Further, the pencil hardness of the surface (outer surface) of the resin film opposite to the surface facing the polarizing film is preferably H or less. The resin film is preferably a diffusion film having light diffusibility.

The resin film may be a film having a concavo-convex shape on one surface. For example, the surface of one side of the resin film is composed of a smooth surface having a ten-point average roughness of less than 0.1 μm, and the other surface is composed of a concave-convex surface having a ten-point average roughness of 0.1 μm or more.

In the polarizing plate of the present invention, an optical compensation film or a protective film may be laminated on the surface of the polarizing film opposite to the surface on which the resin film is laminated.

Moreover, according to the present invention, there is provided a liquid crystal panel comprising a liquid crystal cell and a polarizing plate of the present invention laminated on the liquid crystal cell, wherein the polarizing plate is disposed opposite to a surface of the polarizing film laminated with the resin film. The surface is opposite to the liquid crystal cell.

Furthermore, according to the present invention, there is provided a liquid crystal display device comprising a backlight, a light diffusing plate, and the liquid crystal panel of the present invention, wherein the liquid crystal panel is disposed such that a resin film of the polarizing plate and the light diffusing plate face each other; And a liquid crystal display device comprising a backlight, a light diffusing plate, a light diffusing sheet, and a liquid crystal panel according to the present invention, wherein the liquid crystal panel is disposed such that a resin film of the polarizing plate and the light diffusing sheet face each other.

According to the polarizing plate and the liquid crystal panel of the present invention, since the surface on the resin film side of the polarizing plate has sufficient strength against scratches, even when an optical member such as a light diffusing plate, a light diffusing sheet, or a condensing sheet is superposed on the polarizing plate, The polarizing plate damage can be effectively suppressed or prevented. Therefore, according to the polarizing plate and the liquid crystal panel of the present invention, the liquid crystal display device using the liquid crystal display device does not cause scratches or unevenness, and can provide a liquid crystal display device excellent in image quality. Moreover, according to the present invention, it is possible to reduce the thickness of the liquid crystal display device and the number of members. Such a liquid crystal display device of the present invention is suitably used for a liquid crystal display device for a large-screen liquid crystal television, and particularly a liquid crystal display device for a liquid crystal television that can be wall-mounted.

<Polarizer>

The polarizing plate of the present invention relates to a polarizing plate for a back surface side, comprising a polarizing film comprising a polyvinyl alcohol resin film and a resin film laminated on one or both sides of the polarizing film, wherein the polarizing plate is disposed on the liquid crystal display device. Between the cell and the backlight. The resin film is usually laminated on the polarizing film via an adhesive layer. Hereinafter, the polarizing plate of the present invention will be described in more detail.

(polarized film)

The polarizing film used in the polarizing plate of the present invention is specifically a method in which a dichroic dye is adsorbed to a uniaxially stretched polyvinyl alcohol resin film. As the polyvinyl alcohol-based resin constituting the polyvinyl alcohol-based resin film, a polyvinyl acetate-based resin can be used. As the polyvinyl acetate-based resin, in addition to the polyvinyl acetate of the homopolymer of vinyl acetate, for example, a copolymer of vinyl acetate and another monomer copolymerizable therewith, such as an ethylene-vinyl acetate copolymer, may be mentioned. Wait. Examples of the other monomer copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides having an ammonium group.

The degree of saponification of the polyvinyl alcohol-based resin is usually about 85 to 100 mol%, preferably 98 mol% or more. The polyvinyl alcohol-based resin may be modified, and for example, aldehyde-modified polyethylene formaldehyde, polyvinyl acetaldehyde, and polyvinyl butyral may be used. The degree of polymerization of the polyvinyl alcohol-based resin is usually from about 1,000 to 10,000, preferably from about 1,500 to 5,000.

A film made of such a polyvinyl alcohol-based resin can be used as a raw material film of a polarizing film. The film forming method of the polyvinyl alcohol-based resin is not particularly limited, and a film can be formed by a conventional method. The film thickness of the raw material film composed of the polyvinyl alcohol-based resin is not particularly limited, and is, for example, about 10 to 150 μm.

The polarizing film is usually produced by a step of dyeing a raw material film made of the above polyvinyl alcohol-based resin with a dichroic dye to adsorb the dichroic dye (dyeing step), and adsorbing dichroism. The step of treating the polyvinyl alcohol-based resin film of the dye with a boric acid aqueous solution (boric acid treatment step) and the step of washing with the aqueous boric acid solution (water washing treatment step).

Further, when a polarizing film is produced, the polyvinyl alcohol-based resin film is usually uniaxially stretched, and the uniaxial stretching may be performed before the dyeing step, or in the dyeing step, or after the dyeing step. In the case where the uniaxial stretching is carried out after the dyeing treatment step, the uniaxial stretching may be carried out before the boric acid treatment step or in the boric acid treatment step. Of course, uniaxial stretching can also be performed during these plural phases. Uniaxial extension allows for uniaxial extension between rolls of varying speeds, as well as uniaxial extension using a heated roll. Further, it may be a dry extension which is extended in the atmosphere, or may be a wet extension which is extended in a state of being expanded by a solvent. The stretching ratio is usually about 3 to 8 times.

In the dyeing treatment step, the dyeing of the polyvinyl alcohol-based resin film by the dichroic dye is carried out, for example, by immersing the polyvinyl alcohol-based resin film in an aqueous solution containing a dichroic dye. As the dichroic dye, for example, iodine, a dichroic dye or the like can be used. A dichroic direct dye composed of a disazo dye such as a diazo compound such as C.I. DIRECT RED 39, and a dichroic direct dye composed of a trisazo or a tetrazo compound. Further, the polyvinyl alcohol-based resin film is preferably immersed in water before the dyeing treatment.

When iodine is used as the dichroic dye, a method in which a polyvinyl alcohol-based resin film is immersed in an aqueous solution containing iodine and potassium iodide and dyed is usually used. The content of iodine in the aqueous solution is usually 0.01 to 1 part by weight based on 100 parts by weight of water, and the content of potassium iodide is usually 0.5 to 20 parts by weight based on 100 parts by weight of water. In the case where iodine is used as the dichroic dye, the temperature of the aqueous solution used for dyeing is usually 20 to 40 ° C, and the immersion time (dyeing time) for the aqueous solution is usually 20 to 1800 seconds.

On the other hand, in the case where a dichroic dye is used as the dichroic dye, a method in which a polyvinyl alcohol-based resin film is immersed in an aqueous solution containing a water-soluble dichroic dye and dyed is usually used. The content of the dichroic dye of the solution, usually 100 parts by weight of water in terms of 1 × 10 ^-4 to 10 parts by weight, preferably 1 × 10 ^-3 to 1 parts by weight, particularly preferred of 1 × 10 ^-3 To 1 × 10 ^-2 parts by weight. The aqueous solution may also contain an inorganic salt such as sodium sulfate as a dyeing aid. In the case where a dichroic dye is used as the dichroic dye, the temperature of the aqueous solution used for dyeing is usually 20 to 80 ° C, and the immersion time (dyeing time) for the aqueous solution is usually 10 to 1800 seconds.

The boric acid treatment step can be carried out by immersing the polyvinyl alcohol-based resin film dyed with the dichroic dye in an aqueous solution containing boric acid. The amount of boric acid in the aqueous solution containing boric acid is usually 2 to 15 parts by weight, preferably 5 to 12 parts by weight, per 100 parts by weight of water. In the case where iodine is used as the dichroic dye in the dyeing treatment step, the aqueous solution containing boric acid used in the boric acid treatment step preferably contains potassium iodide. In this case, the amount of potassium iodide in the aqueous solution containing boric acid is usually 0.1 to 15 parts by weight, preferably 5 to 12 parts by weight, per 100 parts by weight of water. The immersion time for the aqueous solution containing boric acid is usually from 60 to 1200 seconds, preferably from 150 to 600 seconds, more preferably from 200 to 400 seconds. The temperature of the aqueous solution containing boric acid is usually 50 ° C or higher, preferably 50 to 85 ° C, more preferably 60 to 80 ° C.

Then, the water-washing treatment step is performed by immersing the polyvinyl alcohol-based resin film after the boric acid treatment in water for example, and performing a water washing treatment. The temperature of the water to be washed is usually 5 to 40 ° C, and the immersion time is usually 1 to 120 seconds. After the water washing treatment, a drying treatment is usually applied to obtain a polarizing film. The drying treatment can be carried out using, for example, a hot air dryer, a far infrared heater or the like. The temperature of the drying treatment is usually from 30 to 100 ° C, preferably from 50 to 80 ° C. The drying treatment time is usually from 60 to 600 seconds, preferably from 120 to 600 seconds.

In this manner, the polyvinyl alcohol-based resin film was subjected to uniaxial stretching, dyeing with a dichroic dye, boric acid treatment, and water washing treatment to obtain a polarizing film. The thickness of the polarizing film is usually in the range of 5 to 40 μm.

(resin film)

The resin film preferably used in the polarizing plate of the present invention is a diffusing film having light diffusibility. When a diffusing film having a light diffusing property is used to impart a light diffusing function to the polarizing plate, when a back side polarizing plate as a liquid crystal display device is used, one or a plurality of sheets disposed between the liquid crystal cell and the backlight can be omitted. Light diffusing sheet. Here, the term "having light diffusibility" of the resin film means that the incident light (typically light from the backlight) incident from the surface of the resin film passes through the resin film, and is on the other side of the resin film. Penetrating light can also be observed in the plural direction of the face side which is different from the straight line penetration direction (the advancing direction of the incident light).

As the diffusing film having light diffusibility, for example, a resin film composed of a concave-convex surface having a smooth surface on one surface and an irregular concave-convex surface on the other surface can be used. Here, the term "smooth surface" means that the ten-point average roughness Rz measured according to JIS B 0601-1994 is less than 0.1 μm, and the "concave surface" refers to the ten-point average roughness measured according to JIS B 0601-1994. Rz is 0.1 μm or more. In order to obtain better light diffusibility, the ten-point average roughness Rz of the uneven surface is preferably 0.5 μm or more. In addition, when the ten-point average roughness Rz is too large, the productivity is lowered by the increase in the thickness of the entire film. Therefore, the ten-point average roughness Rz is preferably 50 μm or less, more preferably 20 μm or less.

When a resin film (diffusion film) having a surface on one side is laminated on a polarizing film, the resin film may be laminated on the uneven surface and the polarizing film, or may be smoothed and polarized. The film is laminated to the ground. Any of the lamination methods can impart a light scattering function to the polarizing plate.

The substrate of the above diffusion film is not particularly limited, and various materials can be used. For example, polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, polyethylene naphthalate, polycarbonate, norbornene resin, polyurethane, polyacrylate, A synthetic polymer such as polymethyl methacrylate; a transparent polymer material such as a natural polymer such as cellulose diacetate or cellulose triacetate. Further, the polymer materials may contain additives such as an ultraviolet absorber, an antioxidant, and a plasticizer as needed.

As a method of producing a diffusion film using the transparent polymer material as a base material, for example, a method of containing a diffusing agent in a base film; a method of providing a layer containing a diffusing agent on one side of a surface of the base film; A method in which one side of the surface of the film is roughened (the surface is uneven) is applied. These methods may be used alone or in combination of two or more.

When a method of containing a diffusing agent in the base film is used, the diffusing agent is preliminarily kneaded in the transparent polymer material constituting the substrate, and formed into a film shape by a casting method or an extrusion method. In this case, for example, a roll having a surface unevenness and a roll having a flat surface as a pair of rolls of the cooling roll unit can be used, and the surface on one side is composed of a concave-convex surface and the surface on the other side is composed of a smooth surface. Diffusion film.

When the method of applying a layer containing a diffusing agent to the side of the surface of the substrate film is carried out, the transparent polymer material is first formed into a film by casting or extrusion, and then the resin liquid in which the diffusing agent is dispersed is dispersed. The resin liquid is applied to a base film to dry or harden the film to produce a diffusion film. Alternatively, a multilayer structure in which a layer containing a diffusing agent is laminated on a base film can be produced by a co-extrusion method using a transparent polymer material constituting a base film and a transparent polymer material in which a diffusing agent is previously kneaded. Diffusion film. In the case of these methods, the surface of the layer containing the diffusing agent usually has an uneven surface.

Further, in the case of a method of roughening the surface of the base film, the transparent polymer material may be first formed into a sheet shape by a casting method or an extrusion method, and then embossed by an embossing processing roll, The sandblasting method roughens the surface to produce a diffusion film.

The diffusing agent is not particularly limited as long as it is colorless or white particles, and any of organic particles and inorganic particles can be used. Examples of the organic particles include polyolefin-based resins such as polystyrene, polyethylene, and polypropylene; and particles composed of a polymer such as an acrylic resin, and may be a crosslinked polymer. Further, a copolymer obtained by copolymerizing two or more kinds of monomers selected from the group consisting of ethylene, propylene, styrene, methyl methacrylate, benzoguanamine, formaldehyde, melamine, and butadiene can be used. Examples of the inorganic particles include particles composed of cerium oxide, polyfluorene oxide, and titanium oxide, and may be glass beads.

As the resin liquid used for the method of applying the resin liquid in which the above-mentioned diffusing agent is dispersed on the base film, a solvent volatile type, a water volatile type resin liquid, a thermosetting type or a photo hardening type resin liquid can be used. As the solvent-evaporable or water-volatile resin liquid, for example, a polymer such as polyacrylate, polymethacrylate, polyvinyl chloride, polyvinyl acetate, cellulose, or synthetic rubber can be dissolved or dispersed in methanol or ethanol. Alcohols such as propanol and isopropanol; cellosolve, celecoxib, etc.; aromatic solvents such as toluene and xylene; organic solvents such as ethyl acetate and dichloromethane Solvent or water. When these solvent volatile type or water volatile type resin liquids are applied to the base film, the organic solvent or water is volatilized by drying to form a film. As the thermosetting resin liquid, a resin liquid obtained by mixing a solution composed of a compound having an epoxy group and a compound condensed with an epoxy group represented by an amine can be used. The photocurable resin liquid may be a resin liquid obtained by adding a conventional photoradical polymerization initiator to a compound having an acrylate group, a methacrylate group, an aromatic group or the like, or having a vinyl ether group or a ring. A resin liquid obtained by adding a conventional photocationic polymerization initiator to a compound of an oxy group. Additives such as an ultraviolet absorber and an antioxidant may be added to these resin liquids as needed.

The haze value of the diffusion film is preferably 5% or more, more preferably 15% or more and 90% or less, in order to impart a good light diffusing function to the polarizing plate. Furthermore, it is more preferably 45% or more and 90% or less. The haze of the diffusion film was measured in accordance with JIS K7136. Further, when the polarizing plate is placed on the liquid crystal display device, in order to increase the brightness of the display screen, the diffusing film is preferably high in total light transmittance. Specifically, the diffusing film preferably has a total light transmittance of 70% or more, more preferably 80% or more, and particularly preferably 85% or more. The total light transmittance of the diffusion film was measured in accordance with JIS K 7361.

The thickness of the diffusion film is not particularly limited, and is preferably from about 20 μm to about 200 μm from the viewpoint of thinness and weight reduction of the polarizing plate, and more preferably from 30 μm to 100 μm.

Further, in the polarizing plate of the present invention, as the resin film laminated on the polarizing film, a resin film composed of a concave-convex surface having a smooth surface on one side and a regular uneven surface on the other surface can be used. When the incident light incident from the surface of the resin film side passes through the resin film, substantially in the direction of the straight-line penetration direction (the advancing direction of the incident light) on the other side of the resin film, Penetrating light was observed. Examples of the regular uneven shape include a lenticular shape, a 稜鏡 shape, and a Fresnel shape. By using the polarizing plate of the resin film having such a regular surface unevenness shape, the brightness can be increased by condensing by adjusting the light emission direction, and the visibility can be improved, and the condensing sheet can be omitted.

The resin film having a regular surface uneven shape can be produced by, for example, a photopolymer process, an irregular extrusion method, a press molding method, an injection molding method, a roll transfer method, or the like. As the substrate, the same transparent polymer material as the diffusion film can be used.

Among the above, a resin film laminated on a polarizing film is preferably a diffusing film having light diffusibility.

Here, the above-mentioned resin film laminated on the polarizing film exhibits a specific steel wool hardness on the surface (outer surface) opposite to the side opposite to the polarizing film. Specifically, the number of the flaws when the outer surface of the resin film is rubbed back and forth 10 times under the condition of a weight of 250 g/cm ² , a stroke width of 5 cm, and a speed of 50 times/minute using the #0000 steel wool is 10 or less. The number is preferably 3 or less, more preferably 0. By using a resin film exhibiting such a steel wool hardness, the surface of the resin film exhibits sufficient scratch resistance, and when a liquid crystal display device is manufactured, a light diffusion plate, a light diffusion sheet, and a light condensing film of a resin film adjacent to the polarizing plate can be prevented. Other optical members such as sheets cause damage to the surface of the resin film. Thereby, the image of the liquid crystal display device does not cause scratches or unevenness, and good image quality can be obtained.

Further, in order to effectively prevent damage to the other optical members such as the light diffusion plate, the light diffusion sheet, and the condensing sheet of the resin film adjacent to the polarizing plate when the liquid crystal display device is formed, the resin film is opposed to the polarizing film. The pencil hardness of the surface (outer surface) on the side opposite to the side is preferably H or less. By having a pencil hardness of H or less, it is possible to effectively prevent the resin film from damaging the surface of other optical members laminated thereon. Further, the pencil hardness of the surface of the resin film was measured in accordance with JIS K 5600-5-4.

A resin film, particularly a diffusion film, which exhibits the above-described steel wool hardness and/or pencil hardness, can be selected from a method for producing the resin film, for example, by adjusting the type of the substrate of the resin film and the type of the diffusing agent. The resin component (resin containing a resin component such as a monomer component) contained in the resin liquid in which the diffusing agent is dispersed is obtained. For example, a transparent resin film such as polyester or acrylic is used as the base film, and an ultraviolet curable hard coat resin liquid in which a diffusing agent is dispersed is applied onto the base film (ultraviolet curing type). The resin composition) is a method in which the layer of the resin liquid is cured by irradiation with ultraviolet rays. As the ultraviolet curable hard coat resin liquid, a compound having one polymerizable carbon-carbon double bond such as an acrylate group or a methacrylate group (for example, a monofunctional (meth) acrylate) is preferably used. The above-mentioned crosslinkable compound of a polymerizable carbon-carbon double bond (for example, a polyfunctional (meth) acrylate) and an ultraviolet curable resin composition of a photopolymerization initiator.

In order to make the resin film exhibit the above-described steel wool hardness and/or pencil hardness, the cured product of the ultraviolet curable resin composition is preferably high in hardness, and therefore, an ultraviolet curable resin composition using a polyfunctional monomer as a curing component is used. Preferably. The polymerizable functional group having a polyfunctional monomer is preferably a group having a polymerizable carbon-carbon double bond, and examples thereof include an acryloyl group, a methacryl group, a vinyl group, and an allyl group. The acryl fluorenyl group and the methacryl oxime group are preferred.

Specific examples of the polyfunctional monomer include ethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, and di(trimethylolpropane)tetrakis(methyl). Acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,3,5-cyclohexyl Polyol poly(meth)acrylates such as triol tri(meth)acrylate; di(meth)acrylate of bisphenol A diglycidyl ether, di(methyl) of hexanediol diglycidyl ether An epoxy (meth) acrylate such as acrylate; an amine ester (meth) acrylate obtained by a reaction of a polyisocyanate with a hydroxyl group-containing (meth) acrylate such as hydroxyethyl (meth) acrylate.

The polyfunctional monomer may be added with a monofunctional monomer as needed in order to adjust the elastic modulus of the hard coat layer, improve adhesion, etc., and the ratio of the monofunctional monomer to the total monomer is preferably 50% by weight or less. More preferably, it is 20% by weight or less. When the ratio of the monofunctional monomer is too large, the desired hardness cannot be obtained.

As the base film, it is preferred that the hardness is low. Here, the term "hardness" means an index of the strength of press-fitting, for example, Vickers hardness, Universal hardness, Martens hardness, and the like. By using a base film having a low hardness, the resin film is easily deformed by an external force, and an appropriate pencil hardness can be exhibited, and a desired effect can be obtained. The hardness of the base film is 130 N/mm ² or less, preferably 90 N/mm ² or less, in terms of Martens hardness. As such a base film, for example, a polyester such as polyethylene terephthalate; an acrylic such as polymethyl methacrylate or a methyl methacrylate-styrene copolymer; polyethylene, polypropylene, or the like can be used. The polyolefin-based film is preferably used in a thickness of from about 20 μm to about 200 μm. Even when a base film having a low hardness is used, a resin film obtained by using a polyfunctional monomer as a curing component can exhibit sufficient steel wool hardness and a desired resin. effect.

When a combination of a base film constituting the resin film and an ultraviolet curable resin composition is selected, it is preferred to first select the base film which exhibits an appropriate hardness. After applying an arbitrary ultraviolet curable resin composition to the selected base film and hardening it, the obtained resin film was evaluated for pencil hardness and steel wool hardness. As a result, in the case where the hardness of the steel wool does not reach the desired hardness, for example, an ultraviolet curable resin composition having a ratio of a higher polyfunctional monomer than the above, or a functional group containing more molecules may be contained. The ultraviolet curable resin composition of the polyfunctional group having a number of bases is coated and hardened on the base film to increase the steel wool hardness of the resin film. Further, in the case of using an ultraviolet curable resin composition having a propylene fluorenyl group or a methacryl fluorenyl group as a polymerizable functional group, ultraviolet light curing in the case of isolating oxygen is also suitable for increasing the steel wool of the obtained resin film. The means of hardness. It is desirable to combine the above methods as needed, or by using an ultraviolet curable resin composition of a polyfunctional monomer having a higher ratio of polyfunctional monomers or a larger number of functional groups in one molecule. Steel wool hardness resin film. The method of isolating the oxygen is, for example, a method of curing the coated surface of the ultraviolet curable resin composition by a resin or a metal, and curing it in a nitrogen atmosphere.

Further, the combination of the base film and the ultraviolet curable resin composition is selected in the above-described order so that the steel wool hardness of the obtained resin film is at a desired value or more (to coat the surface of the resin film with steel wool at a load of 250 g/cm ² , stroke) In the case where the number of the flaws when the width is 5 cm and the speed is 50 times back/minute, the number of the flaws is 10 or less, the pencil hardness of the resin film is usually less than the desired hardness (pencil hardness H). The case of the desired hardness range can be adjusted by reducing the use ratio of the polyfunctional monomer without affecting the hardness of the steel wool.

A layer for bonding an adhesive or an adhesive of the liquid crystal cell and the polarizing plate may be formed on the surface of the polarizing film opposite to the surface to which the resin film is bonded. Further, a transparent film such as a protective film or an optical compensation film may be laminated on the surface of the polarizing film opposite to the surface to which the resin film is bonded, and a layer of an adhesive or an adhesive may be formed on the transparent film. The transparent film may, for example, be a cellulose resin film such as a cellulose triacetate film (TAC film), an olefin resin film, an acrylic resin film, or a polyester resin film such as polyethylene terephthalate. Further, an optical functional film to be described later may be laminated on the transparent film, and a layer of an adhesive or an adhesive may be formed on the optical functional film.

The cellulose-based resin constituting the cellulose-based resin film refers to a partially esterified or fully esterified cellulose, and examples thereof include cellulose acetate, propionate, butyrate, and mixed esters thereof. Wait. More specifically, for example, cellulose triacetate, cellulose diacetate, cellulose acetate propionate, cellulose acetate butyrate or the like can be mentioned. When such a cellulose-based resin is produced into a film, a conventional method such as a solvent casting method or a melt extrusion method can be suitably used. For the cellulose-based resin film, a commercially available product can be used, and examples thereof include "FUJITAC TD80" (manufactured by FUJIFILM Co., Ltd.), "FUJITAC TD80UF" (manufactured by FUJIFILM Co., Ltd.), and "FUJITAC TD80UZ" (manufactured by FUJIFILM Co., Ltd.). , "KC8UX2M" (Konica Minolta OPTO (share) system), "KC8UY" (Konica Minolta OPTO (share) system).

In addition, the optical compensation film which consists of a cellulose-type resin film, for example, the film which has the compound which has a phase-difference adjustment function in the said cellulose-type resin film, and the A film of a compound having a poor adjustment function; a film obtained by subjecting a cellulose resin film to uniaxial stretching or biaxial stretching.

For example, "WV film Wide View Film "WV BZ 438"" and "WV film Wide View Film "WV EA"", which are manufactured by FUJIFILM Co., Ltd., are used as the optical compensation film which is a commercially available cellulose resin film. "KC4FR-1" and "KC4HR-1" made by Konica Minolta OPTO Co., Ltd.

The thickness of the protective film or optical compensation film composed of the cellulose resin film is not particularly limited, and is preferably in the range of 20 to 90 μm, more preferably in the range of 30 to 90 μm. When the thickness is less than 20 μm, the treatment of the film is difficult, and when it exceeds 90 μm, the workability is deteriorated, and the thickness and weight of the obtained polarizing plate are disadvantageous.

The optical compensation film which consists of said olefin type resin film is a cycloolefin type resin film which is uniaxially extended or biaxially extended, for example. When the polarizing plate of the present invention is used for a liquid crystal panel for a large liquid crystal television, particularly a liquid crystal panel having a liquid crystal cell of a vertical orientation (VA) mode, the optical compensation film is an optical product and an extension of the cycloolefin resin film is optically characterized. The viewpoint of durability is also suitable. Here, the cycloolefin-based resin film is, for example, a film composed of a thermoplastic resin of a monomer unit composed of a cyclic olefin (cycloolefin) such as a norbornene or a polycyclic norbornene-based monomer. The cycloolefin-based film may be a ring-opening polymer using a single cyclic olefin, a hydrogenated product using a ring-opening copolymer of two or more kinds of cyclic olefins, or a cyclic olefin and a chain olefin and/or having a vinyl group. An addition copolymer of an aromatic compound or the like. Further, it is also effective to introduce a polar group into the main chain or the side chain.

Commercially available thermoplastic cycloolefin-based resins, such as "Topas" sold by Ticona, Germany, "ARTON" sold by JSR (shares), "ZEONOR" and "ZEONEX" sold by Japan's ZEON (shares), Mitsui "APEL" (all of which are trade names) sold by chemical companies is suitable for use. By forming a film of such a cycloolefin type resin, a cycloolefin type resin film can be obtained. As a film forming method, a conventional method such as a solvent casting method or a melt extrusion method is suitably used. In addition, "S-SINA" and "SCA40" sold by Sekisui Chemicals Co., Ltd., "ZEONOR film" sold by OPTES, and "ARTON film" sold by JSR (shares) are all trade names. The cycloolefin-based resin film which has been formed into a film is also commercially available, and these are suitable for use.

When the thickness of the optical compensation film composed of the extended cycloolefin-based resin film is too thick, the workability is deteriorated, the transparency is lowered, or the thickness of the polarizing plate is disadvantageous, and the thickness is preferably about 20 to 80 μm.

An adhesive is usually used for bonding the polarizing film and the resin film, and bonding the protective film or the optical compensation film and the polarizing film which are laminated as needed. When the protective film or the optical compensation film is bonded to the polarizing film, the adhesive used for bonding the adhesive film and the protective film or the optical compensation film may be the same kind of adhesive. For different kinds of adhesives. Examples of the adhesive used for bonding the films include water, that is, those in which the adhesive component is dissolved in water or dispersed in water. A preferred example of the adhesive is a resin composition using a polyvinyl alcohol resin or an amine ester resin as an adhesive component.

When a polyvinyl alcohol-based resin is used as the adhesive component, the polyvinyl alcohol-based resin may be a partially saponified polyvinyl alcohol or a fully saponified polyvinyl alcohol, and may be a carboxyl-modified polyvinyl alcohol or acetamidine. A modified polyvinyl alcohol-based resin such as a modified polyvinyl alcohol, a methylol-modified polyvinyl alcohol, or an amine-modified polyvinyl alcohol. Usually, a polyvinyl alcohol-based resin is used as an adhesive for an adhesive component, and is prepared as an aqueous solution of a polyvinyl alcohol-based resin. The concentration of the polyvinyl alcohol-based resin in the subsequent agent is usually 1 to 10 parts by weight, preferably 1 to 5 parts by weight, per 100 parts by weight of water.

In order to improve the adhesiveness, a polyvinyl alcohol-based resin is used as an adhesive for the adhesive component, and a curable component such as glyoxal or a water-soluble epoxy resin or a crosslinking agent is preferably added. As the water-soluble epoxy resin, a polyamine amine obtained by reacting a polyalkylene polyamine such as diethylenetriamine or triethylenetetramine with a dicarboxylic acid such as adipic acid and epichlorohydrin is preferably used. Polyamine polyamine epoxy resin. For example, "SUMIREZ RESIN 650" (manufactured by Sumitomo Chemtex Co., Ltd.), "SUMIREZ RESIN 675" (manufactured by Sumitomo Chemtex Co., Ltd.), and "WS-" are exemplified as such a commercial product of the polyamine polyamine epoxy resin. 525" (Japan PMC (share) system) and so on. The amount of the curable component and the crosslinking agent added (in the case of the total addition) is usually 1 to 100 parts by weight, preferably 1 to 50 parts by weight, per 100 parts by weight of the polyvinyl alcohol-based resin. . When the amount of the curable component and the cross-linking agent is less than 1 part by weight based on 100 parts by weight of the polyvinyl alcohol-based resin, the effect of improving the adhesion tends to be small, and the curable component and the cross-linking agent tend to be cross-linked. When the amount of the agent added exceeds 100 parts by weight based on 100 parts by weight of the polyvinyl alcohol-based resin, the adhesive layer tends to become brittle.

Further, when an amine ester resin is used as the adhesive component, as an example of a suitable adhesive composition, for example, a mixture of a polyester-based ionic polymer-type amine ester resin and a compound having a glycidoxy group. Here, the polyester-based ionic polymer-type amine ester resin refers to an amine ester resin having a polyester skeleton, and a small amount of an ionic component (hydrophilic component) is introduced into the skeleton. Such an ionic polymer type amine ester resin is emulsified directly into water as an emulsion without using an emulsifier, and is suitable as a water-based adhesive.

The polyester-based ionic polymer-type amine ester resin is known per se, and is described, for example, in JPH07-97504-A as an example of a polymer dispersant for dispersing a phenol resin in an aqueous medium, and is described in JP2005-70140-A and JP2005-208456-A discloses a method in which a mixture of a polyester-based ionic polymer-type urethane resin and a compound having a glycidoxy group is used as an adhesive, and a cycloolefin film composed of a polyvinyl alcohol-based resin is bonded to a cycloolefin-based resin film. form.

As a method of applying an adhesive to a polarizing film and/or a film (resin film, protective film or optical compensation film) bonded thereto, a conventionally known method such as a flow casting method or a wire bar coating method can be used. Method, gravure coating method, comma coater method, doctor blade coating method, die coating method, dip coating method, spray method, and the like. The casting method is a method in which a film of an object to be coated is moved to a surface thereof in a direction perpendicular to a vertical direction, an approximately horizontal direction, or an oblique direction therebetween, and an adhesive is applied to the surface thereof. After the application of the adhesive, the polarizing film and the film to be bonded thereto are superposed, and the film is sandwiched by a nip roll to bond the film. The bonding of the film using the nip rolls can be carried out, for example, by applying a pressure-sensitive adhesive to a uniform pressure by a roll or the like; after applying the adhesive, it is uniformly pressed by pressing between the rolls and the rolls. The method of spreading. In the former case, metal, rubber, or the like can be used as the material of the roller. In addition, in the latter case, the plurality of rolls may be of the same material or different materials.

Further, in order to improve the adhesion on the surface of the adhesive layer, surface treatment such as plasma treatment, corona treatment, ultraviolet irradiation treatment, flame treatment, or saponification treatment may be appropriately applied. The saponification treatment may, for example, be a method of immersing in an aqueous alkali solution such as sodium hydroxide or potassium hydroxide.

After the bonding, drying is performed, and the adhesive layer is cured to obtain a polarizing plate. The drying treatment is carried out, for example, by blowing hot air, and the temperature is usually in the range of 40 to 100 ° C, preferably 60 to 100. Within the °C range. Moreover, the drying time is usually from 20 to 1200 seconds.

The thickness of the adhesive layer after drying is usually 0.001 to 5 μm, preferably 0.01 to 2 μm, more preferably 0.01 to 1 μm. When the thickness of the adhesive layer is less than 0.001 μm, there is a fear that the thickness of the adhesive layer is insufficient, and when the thickness of the adhesive layer exceeds 5 μm, the appearance of the polarizing plate may be poor.

Further, after the drying, the aging is carried out at a temperature of at least room temperature of at least half a day, preferably for several days or more, to obtain a sufficient bonding strength. A preferred ripening temperature is in the range of 30 to 50 ° C, preferably 35 to 45 ° C. When the aging temperature exceeds 50 ° C, it is likely to cause "winding" in a state of being wound into a roll. Further, the humidity at the time of ripening is not particularly limited as long as the relative humidity is in the range of 0 to 70% RH. The ripening time is usually from 1 to 10 days, preferably from 2 to 7 days.

Further, as the above-mentioned adhesive, a photocurable adhesive can also be used. The photocurable adhesive agent may, for example, be a mixture of a photocurable epoxy resin and a photocationic polymerization initiator. In the case of using a photocurable adhesive, the photocurable adhesive is cured by irradiation of an active energy ray. The light source of the active energy ray is not particularly limited, and is preferably an active energy ray having a light-emitting distribution at a wavelength of 400 nm or less, specifically, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high pressure mercury lamp, a chemical lamp, a black lamp, and a microwave-excited mercury lamp. A metal halide lamp or the like is preferred.

The light irradiation intensity of the photocurable adhesive is appropriately determined depending on the composition of the photocurable adhesive, and is not particularly limited, and the irradiation intensity in a wavelength region effective for activation of the polymerization initiator is 0.1 to 6000 mW/cm ^{2 .} good. When the irradiation intensity is 0.1 mW/cm ² or more, the reaction time is not too long, and when it is 6000 mW/cm ² or less, the yellowness of the epoxy resin is caused by the heat radiated from the light source and the heat release when the photocurable adhesive hardens. There are few doubts about the deterioration of the polarizing film. The light-curing adhesive for the photocurable adhesive is controlled for each of the cured photocurable adhesives, and is not particularly limited. The integrated light amount expressed as the product of the irradiation intensity and the irradiation time is set to 10 to 10000 mJ/m ^{2 .} Preferably. When the integrated light amount of the photocurable adhesive is 10 mJ/m ² or more, the active species derived from the polymerization initiator can be sufficiently generated, and the curing reaction can be more reliably performed, and the integrated light amount is 10000 mJ/m ² or less, and the irradiation time is obtained. It won't get too long to maintain good productivity.

Further, in the case where the photocurable adhesive is cured by irradiation with an active energy ray, the polarizing degree, the transmittance and the hue of the polarizing film, and the transparency of the resin film, the protective film, and the optical compensation film are not lowered. Hardening is preferred under the conditions of various functions of the polarizing plate.

In the polarizing plate of the present invention, the surface of the polarizing film opposite to the side on which the resin film is laminated (on the case of laminating the protective film or the optical compensation film) is preferably an adhesive layer. As the adhesive for such an adhesive layer, conventionally known adhesives such as an acrylic adhesive, an amine ester adhesive, and a polyoxygen adhesive can be used without limitation. Among them, an acrylic adhesive is preferably used from the viewpoints of transparency, adhesion, reliability, secondary workability and the like. The adhesive layer is formed by applying such an adhesive to a solution such as an organic solvent, and applying it to a base film (for example, a polarizing film or the like) by a die coater or a gravure coater. In addition to the drying method, a method of transferring a sheet-like adhesive formed on a plastic film subjected to a release treatment (referred to as a separation film) onto a substrate may also be employed. The thickness of the adhesive layer is not particularly limited and is preferably in the range of 2 to 40 μm.

The optical functional film can be adhered to the surface of the polarizing plate on which the adhesive layer is formed, via the adhesive layer. As the optical functional film, for example, an optical compensation film obtained by coating and orienting a liquid crystalline compound on a surface of a substrate; a reflective polarizing film which can penetrate a certain polarized light and reflect a polarized light having an opposite property; polycarbonate a retardation film composed of a resin; a retardation film composed of a cyclic polyolefin resin; a film having an anti-glare function having a concave-convex shape on the surface; a film having a surface anti-reflection function; and a surface having a reflection function a reflective film; and a transflective film having both a reflective function and a penetrating function. Commercial products such as "WV film" (made by FUJIFILM Co., Ltd.) and "NH film" (manufactured by Nippon Oil Co., Ltd.) are commercially available as optical compensation films which are coated and oriented with a liquid crystal compound on the surface of the substrate. ), "NR film" (Nippon Oil Co., Ltd.), etc. A commercially available product of a reflective polarizing film that penetrates a certain polarized light and reflects a polarized light having the opposite property, for example, "DBEF" (made by 3M Company, available from Sumitomo 3M (share) in Japan), "APF" ( 3M company system, Japan can be obtained from Sumitomo 3M (shares), etc. In addition, as a commercial product of a retardation film which is a cyclic polyolefin resin, for example, "ARTON film" (manufactured by JSR), "S-SINA" (made by Sekisui Chemical Co., Ltd.), "ZEONOR film" (made by OPTES).

The polarizing plate of the present invention is preferably used as a back side polarizing plate disposed between a liquid crystal cell and a backlight provided in a liquid crystal display device.

<Liquid crystal panel and liquid crystal display device>

The liquid crystal panel of the present invention includes a liquid crystal cell and a polarizing plate of the present invention laminated on the liquid crystal cell, and the liquid crystal cell and the polarizing plate are opposite to the surface of the polarizing film opposite to the surface on which the resin film is laminated, and the liquid crystal cell. The adhesive film layer is bonded to the outer surface of the liquid crystal panel (that is, the resin film is formed). In the liquid crystal panel of the present invention, the resin film is used as a backlight side (the polarizing plate of the present invention is disposed between the liquid crystal cell and the backlight) for use in a liquid crystal display device. In the liquid crystal panel of the present invention, a polarizing plate is provided on the front side of the liquid crystal cell (the side opposite to the side where the polarizing plate of the present invention is laminated on the visual side of the liquid crystal display device), and the front side of the liquid crystal cell The polarizing plate to be provided is not particularly limited, and a conventionally known polarizing plate can be used. For example, a polarizing plate which is subjected to anti-glare treatment, hard coating treatment, anti-reflection treatment, or the like.

Further, a polarizing plate of a polyethylene terephthalate film, an acrylic film, or a polypropylene film may be laminated on one side of the polarizing plate.

In the liquid crystal display device of the present invention, the resin film in which the polarizing plate of the invention is disposed is a liquid crystal panel on the backlight side. In the liquid crystal display device of the present invention, the liquid crystal panel of the polarizing plate of the present invention is bonded to the back side of the liquid crystal cell, and the image is excellent in image quality without scratches and unevenness, and is excellent in image quality. Further, since the resin film of the polarizing plate of the present invention is disposed on the back side of the liquid crystal panel, the adhesion between the liquid crystal panel and the backlight system can be prevented, and the visibility can be improved. Moreover, damage to other optical members adjacent to the resin film can be prevented.

In the liquid crystal display device of the present invention, a configuration other than the liquid crystal panel may be a suitable configuration of a conventional liquid crystal display device, and for example, a backlight, a light diffusing plate, and a liquid crystal panel of the present invention may be provided in order. The backlight, the light diffusing plate, the light diffusing sheet, and the liquid crystal panel of the present invention are provided in this order.

In the former case, the liquid crystal panel is disposed so that the resin film of the polarizing plate of the invention and the light diffusing plate face each other. In the latter case, the liquid crystal panel is disposed such that the resin film of the polarizing plate of the invention and the light diffusing sheet face each other. Further, other optical members such as a condensing sheet may be disposed between the backlight and the liquid crystal panel as needed.

In the liquid crystal display device of the present invention, when a diffusing film having light diffusibility is used as the resin film, since the light diffusing property of the polarizing plate of the present invention used for the back surface side is imparted, the conventional light diffusing can be omitted. A part or all of the light-diffusing sheet on the board can reduce the thickness and weight of the liquid crystal display device. In addition, when a resin film (a resin film having a regular uneven shape) other than the diffusing film having light diffusibility is used as the resin film, the brightness can be improved by collecting light by adjusting the light emission direction, and the visibility can be improved. The condensed sheet is omitted.

(Example)

The invention is illustrated in more detail below by way of examples, but the invention is not limited to the examples. In addition, in the example, the content and the usage amount and the part are indicated, unless otherwise specified, that is, based on the weight.

In the following examples, the steel wool hardness (the number of scratches when the steel wool was rubbed) on the outer surface of the diffusion film was measured under the following conditions, and the results were visually observed.

Model of steel wool: #0000号; shape of the outer surface of the steel wool contact diffusing film (friction): 1 square 2cm square (area 4cm ² ), the fiber of the steel wool is parallel to the edge, in the fiber direction Back and forth; load on steel wool: 250 g/cm ² (1000 g/4 cm ² ); stroke width of steel wool: 5 cm (10 cm back and forth); speed at back and forth friction: 50 round trips/minute (500 cm/min).

Further, the pencil hardness of the outer surface of the diffusion film was measured by a weight of 500 g using an electric pencil scratch hardness tester (manufactured by Yasuda Seiki Co., Ltd., No. 553-M) according to JIS K 5600-5-4. .

(Manufacturing Example 1: Production of Polarizing Film)

A polyvinyl alcohol film having a thickness of 75 μm composed of a polyvinyl alcohol having an average polymerization degree of about 2400 and a saponification degree of 99.9 mol% or more was immersed in pure water at 30° C., and then immersed in a weight of iodine/potassium iodide/water at 30° C. The ratio is in an aqueous solution of 0.02/2/100. Then, an aqueous solution having a weight ratio of potassium iodide/boric acid/water of 12/5/100 was immersed at 56.5 °C. Subsequently, the mixture was washed with pure water at 8 ° C, and then dried at 65 ° C to obtain a polarizing film on which a iodine was adsorbed on a polyvinyl alcohol film. The extension system was mainly carried out in the steps of iodine dyeing and boric acid treatment, and the total stretching ratio was 5.3 times.

(Production Example 2: Production of diffusion film A)

Each of the following components was prepared as an ultraviolet curable resin composition in which ethyl acetate was dissolved in an ethyl acetate concentration of 60% by weight.

Pentaerythritol triacrylate 60 parts

Polyfunctional amine esterified acrylate (reaction product of hexamethylene diisocyanate and pentaerythritol triacrylate) 40 parts

Then, a photopolymerization initiator "Lucirin TPO" (manufactured by BASF Corporation, chemical name: 2,4,6-trimethylbenzhydryldiphenyl) was added to 100 parts by weight of the solid content of the ultraviolet curable resin composition. 5 parts by weight of acrylonitrile-based organic fine particles (manufactured by Soken Chemical Co., Ltd., average particle diameter: 8 μm, refractive index: 1.55), 11.25 parts by weight, and a coating liquid was prepared.

The coating liquid was applied to a commercially available polyethylene terephthalate film (thickness: 38 μm) so that the thickness of the resin layer after curing was 10 μm, and after drying, it was cured by ultraviolet irradiation to obtain a polymer. A diffusion film A having a hardened resin layer formed on the ethylene terephthalate film.

The pencil hardness of the outer surface of the obtained diffusing film A (the surface on the side opposite to the side bonded to the polarizing film and the surface of the hardened resin layer in which the diffusing agent was dispersed) was H. Further, the outer surface of the obtained diffusion film A had one number of flaws when rubbed under the above conditions with steel wool.

(Production Example 3: Production of diffusion film B)

In the same manner as described in Example 1 of JP2000-75136-A, a diffusion film B having a fine uneven structure on the surface of a cellulose triacetate film as a substrate was produced. The fine uneven structure is formed by roughening a base film by a sand blast method.

The pencil hardness of the outer surface (fine uneven surface) of the obtained diffusion film B was B. Further, when the outer surface of the obtained diffusion film B was rubbed with steel wool under the above conditions, the number of scratches was confirmed to be at least 50 or more.

<Example 1>

Using the photocurable adhesive, the diffusion film A obtained in Production Example 2 was bonded to the surface of one side of the polarizing film obtained in the above Production Example 1, and the cellulose triacetate film was bonded to the other surface of the polarizing film (thickness). 80 μm, manufactured by Konica Minolta Opto Co., Ltd., the adhesive was cured by ultraviolet irradiation to obtain a polarizing plate. On the outer surface of the cellulose triacetate film of the polarizing plate, a layer of an acrylic adhesive having a thickness of 25 μm was provided.

The polarizing plate is placed on the back surface of the liquid crystal cell via the adhesive layer, a commercially available polarizing plate is placed on the front surface of the liquid crystal cell, and the liquid crystal panel is assembled to be combined with a commercially available tantalum film, light diffusing plate, and backlight. , making a liquid crystal display device. In the liquid crystal display device, the liquid crystal panel is configured such that the diffusion film A side faces the ruthenium film.

When the liquid crystal display device is assembled, in order to accurately determine the position at which the liquid crystal panel is overlapped, the liquid crystal panel is slid and adjusted on the ruthenium film. When the display screen of the liquid crystal display device was visually observed, a screen having no scratches and unevenness was obtained, and the visibility was good.

<Comparative Example 1>

A polarizing plate was obtained in the same manner as in Example 1 except that the diffusion film B obtained in Production Example 3 was used instead of the diffusion film B obtained in Production Example 2, and a liquid crystal display was produced in the same manner as in Example 1 except that the polarizing plate was used. Device. When the display screen of the liquid crystal display device is visually observed, only a screen showing scratches and unevenness is obtained, and the visibility is poor. After the observation, the liquid crystal panel was taken out from the liquid crystal display device, and the surface (the outer surface of the diffusion film B) was observed, and it was confirmed that the surface was scratched.

Claims (8)

A polarizing plate for a back side, comprising: a polarizing film formed by adsorbing a uniaxially stretched polyvinyl alcohol resin film oriented with a dichroic dye; and a resin film laminated on at least one side of the polarizing film, wherein The number of flaws of the resin film opposite to the opposite side of the polarizing film is 10 pieces when the steel wool is rubbed back and forth 10 times under the conditions of a weight of 250 g/cm ² , a stroke width of 5 cm, and a speed of 50 times/minute. Hereinafter, it is disposed between the liquid crystal cell included in the liquid crystal display device and the backlight. The polarizing plate for the back side of the first aspect of the patent application, wherein the surface of the resin film opposite to the surface facing the polarizing film has a pencil hardness of H or less. A polarizing plate for a back side of the first or second aspect of the patent application, wherein the resin film is a diffusing film having light diffusibility. A polarizing plate for a back side of the first or second aspect of the patent application, wherein the surface of one side of the resin film is composed of a smooth surface having a ten-point average roughness of less than 0.1 μm, and the surface of the other side is It is composed of a concave-convex surface having a ten-point average roughness of 0.1 μm or more. A polarizing plate for a back side of the first or second aspect of the invention is characterized in that an optical compensation film or a protective film is laminated on a surface of the polarizing film opposite to the surface on which the resin film is laminated. A liquid crystal panel comprising a liquid crystal cell and a polarizing plate for a back side according to any one of the first to fifth aspects of the present invention, wherein The polarizing plate is disposed such that a surface of the polarizing film opposite to the surface on which the resin film is laminated faces the liquid crystal cell. A liquid crystal display device comprising a backlight, a light diffusing plate, and a liquid crystal panel according to claim 6 in which the liquid crystal panel is disposed such that the resin film and the light diffusing plate of the polarizing plate face each other. A liquid crystal display device comprising a backlight, a light diffusing plate, a light diffusing sheet, and a liquid crystal panel according to claim 6 in which the liquid crystal panel is disposed such that a resin film of the polarizing plate and the light diffusing sheet face each other.