Optical compensating sheet, polarizing plate, and liquid crystal display device

Abstract

The object of the present invention is to provide an optical compensation sheet for improving the display quality of a liquid crystal display device, a polarizer having the optical compensation sheet, and a liquid crystal display device. The optical compensation sheet is formed by sequentially laminating an alignment film and an optically anisotropic layer on a transparent support containing at least fine particles with an average primary particle diameter of 80 nm or less and a film thickness of 20 μm or more and 80 μm or less, wherein the transparent support is The arithmetic average roughness Ra of the surface irregularities on the side surface of the alignment film based on JISB0601-1994 is 0.0002 μm to 0.1 μm, the ten-point average roughness Rz is 0.0002 μm to 0.3 μm, and the maximum height Ry is 0.002 μm to 0.5 μm , the Re value defined by the formula (I) and (II) of the transparent support is 2nm or more and 200nm or less, and the value of Rth is in the range of 50nm or more and 400nm or less. In the formula, nx is the slow axis direction in the transparent support body ny is the refractive index in the fast axis direction in the plane of the transparent support; nz is the refractive index in the thickness direction of the transparent support; and d is the thickness of the transparent support. (I) Re=(nx-ny)×d (II) Rth={(nx+ny) / 2-nz}×d.

Description

[0001] This application is a divisional application of Chinese Patent Application No. 200410061869.3 submitted on June 25, 2004. technical field [0002] The present invention relates to an optical compensation sheet for improving the viewing angle (also referred to as viewing angle) of a liquid crystal display device, a polarizing plate (also referred to as a polarizer) using the optical compensation sheet, and a liquid crystal display device. Background technique [0003] A liquid crystal display device usually consists of a liquid crystal cell, a polarizing plate, and an optical compensation film (retardation plate). In a transmissive liquid crystal display device, two polarizers are installed on both sides of the liquid crystal unit, and one or two optical compensation sheets are disposed between the liquid crystal unit and the polarizer. For a reflective liquid crystal display device, a reflective plate, a liquid crystal unit, an optical compensation sheet, and a polari...

AI Technical Summary

Problems solved by technology

[0017] In order to respond to the demand for cost reduction due to weight reduction and improvement in productivity, thinning of the transparent support is also strongly desired, but the strength is reduced due to thinning, and it is practically used especially when used in a large liquid crystal display device. question on

Such a problem cannot be fully solved according to the current proposal, and it is strongly desired to increase the strength of the support, but if the strength of the support is only increased, the problems of poor optical properties and reduced visibility will arise.

[0018] In addition, in a liquid crystal display device composed of a large display panel of 20 inches or more, it will be found that there are problems that have not been fully studied in the prior art.

Images