JPH05341123A - Polarizing plate and liquid crystal display - Google Patents

Abstract

PURPOSE:To eliminate the generation of moire stripe of a normally white type liquid crystal display, and obtain the faceplate easy to be seen by specifying the mean height of projecting parts of the surface of a coating layer in a polarizing plate coated with a glaring preventing function layer. CONSTITUTION:A protecting film is attached to both surfaces of a polarizer, and a hard coating layer made of the composition, which includes the ultraviolet rays hardening type resin and inorganic particle and/or organic particle, is laminated on the other surface of one protecting film, which is not attached to the polarizer. As the ultraviolet rays hardening type resin, the resin, which has the excellent adhesion with the protecting film and a high coating hardness and the excellent chemical resistance and which is hardened easily by the ultraviolet rays, is desirably used. The mean height of projecting parts of the surface of a hard coating layer is set at 7m or less. A glaring preventing polarizing plate, which is thereby obtained, is used for the upper polarizing plate and laminated on a liquid crystal coating device so that the hard coating layer is positioned as the top surface, and under the condition that a back light is lighted, the moire stripe is not generated in a transmission type display to obtain the faceplate easy to be seen.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polarizing plate and a liquid crystal display device.

[0002]

2. Description of the Related Art Polarizing plates are widely used in liquid crystal display devices to increase the size of the display screen.
Many functions are required as the field of use expands.
In a portable personal computer or a word processor, a polarizing plate coated with an antiglare function layer is often used in order to prevent external light from being reflected on a liquid crystal display screen to make it difficult to see the display. The antiglare functional layer is formed by curing and coating the upper surface of the polarizing plate with a composition containing an ultraviolet curable resin and inorganic and / or organic particles. When a polarizing plate with an antiglare function layer is laminated on the upper surface of a liquid crystal display device, reflection of external light can be suppressed. However, although the normally white liquid crystal display has an antiglare effect, it causes a problem that moire fringes occur. The polarizing plate with the antiglare function layer so far does not have a sufficiently high visibility screen.

In the polarizing plate coated with the antiglare function layer, the inventors of the present invention control the average height of the convex portions on the surface of the coating layer to prevent moire fringes even in a normally white liquid crystal display device. The inventors have found that a screen that does not occur and is very easy to see is obtained, and the present invention has been completed.

[0004]

That is, the present invention provides a polarizing plate comprising a cured coating layer composed of a composition containing an ultraviolet curable resin and inorganic particles and / or organic particles laminated on one side, And the polarizing plate for antiglare, wherein the average height of the convex portions on the surface of the coating layer is 7 μm or less,
The present invention relates to a liquid crystal display device using the same.

The present invention will be described in detail below. Examples of the UV-curable resin used in the present invention include UV-curable epoxy acrylate resin and the like, which have good adhesion to a protective film such as triacetyl cellulose, and which can be easily cured by UV to form a coating. Any resin may be used as long as it has high hardness and chemical resistance.

The inorganic particles and organic particles used in the present invention include, for example, amorphous silica powder, polycarbonate particles and the like, which may be used in combination.

As the polarizer used in the polarizing plate of the present invention, a usual one is used, and examples thereof include polyvinyl alcohol films, polyvinyl formal films, polyvinyl acetal films, and poly (ethylene-acetic acid) copolymer saponified films. Whether the iodine- and / or dye-based polarizing film or polyvinyl alcohol-based film in which iodine and / or dichroic dye is adsorbed and oriented on the hydrophilic polymer film is dehydrated, or the polyvinyl chloride film is dehydrochlorinated Then, a polyene-based polarizing film obtained by orienting the polyene is exemplified.

A triacetyl cellulose film (having a thickness of about 5) which is usually excellent in transparency as a protective film for a polarizer.
0 μm to 200 μm) is used, and the film is laminated on both surfaces of the polarizer with a polyvinyl alcohol adhesive. As one of the protective films of the antiglare polarizing plate of the present invention, one having an ultraviolet curable resin and a composition containing inorganic particles and / or organic particles cured and coated on the surface not bonded to the polarizer is used.

The average height of the protrusions on the surface of the cured coating layer is 7 μm.
It is necessary to make it below, and preferably it is 5 μm or less. When the display is laminated in a liquid crystal display device with the cured coating layer as the upper polarizing plate and the cured coating layer as the upper polarizing plate, and a transmissive display is viewed under a backlight, a screen that is very easy to see without moire fringes. Becomes

[0010]

According to the present invention, even in a normally white liquid crystal display device, moire fringes do not occur, and a display screen with excellent visibility can be obtained.

[0011]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to the examples.
The average height of the convex portions shown in the present invention was measured with a surface roughness meter (Surfcom 570A-3DF / manufactured by Toyo Seimitsu Co., Ltd.).

Example 1 A triacetyl cellulose film (Sanyo Kokusaku Pulp Co., Ltd.) in which a cured coating layer composed of amorphous silica powder (Cyroid 244, manufactured by Fuji Devinson) and an ultraviolet curable epoxy acrylate resin was laminated. Product name: TAC-HA-
5, the average height of the convex portions on the surface of the cured coating layer is 3 μm)
Is bonded to one surface of an iodine-based polarizer, and the other surface is bonded to a normal triacetyl cellulose film to obtain an antiglare polarizing plate. When the antiglare polarizing plate is laminated on the upper surface of the liquid crystal display device and the display is viewed in a transmissive mode under lighting of a backlight, moire fringes do not occur and the screen becomes very easy to see.

Example 2 A cured coating layer comprising a polycarbonate resin bead and an ultraviolet curable resin (the average height of the convex portions on the surface of the cured coating layer is 3).
The same experiment as in Example 1 is carried out except that the antiglare polarizing plate is obtained. When the antiglare polarizing plate is laminated on the upper surface of the liquid crystal display device and the display is viewed in a transmissive mode with the backlight lit, no moire fringes occur and the screen becomes very easy to see.

Comparative Example 1 An antiglare polarizing plate was obtained by conducting the same experiment as in Example 1 except that the average height of the convex portions on the surface of the cured coating layer was 8 μm. When the polarizing plate with an antiglare function is laminated on the upper surface of a liquid crystal display device and a display is viewed with a transmissive display under lighting of a backlight, moire fringes are generated, which makes the screen very difficult to see.

Claims (2)

[Claims] 1. A polarizing plate comprising a cured coating layer composed of a composition containing an ultraviolet curable resin and inorganic particles and / or organic particles laminated on one side, and the average of the convex portions on the surface of the coating layer. A polarizing plate for antiglare, which has a height of 7 μm or less. 2. A polarizing plate comprising a cured coating layer composed of a composition containing an ultraviolet curable resin and inorganic particles and / or organic particles laminated on one side, and the average of the convex portions on the surface of the coating layer. A liquid crystal display device comprising a stack of antiglare polarizing plates having a height of 7 μm or less.