Liquid crystal display having improved retardation film

Abstract

A liquid crystal display having improved retardation plate is described. In the liquid crystal display, at least one of two panel plates has a polarizer placed on an outer side which is opposite to a liquid crystal layer and a quarter wavelength retardation plate between a substrate glass and the polarizer. The quarter wavelength retardation plate is composed of two retardation films including a half wavelength and a quarter wavelength retardation film. A slow axis of a half λ film which is adjacent to the polarizer makes an angle of Θ 1 with a transmissive axis of the polarizer and that of a quarter λ film which is adjacent to the substrate glass makes an angle of Θ 2 where Θ 2 =2×Θ 1 ±45 degree. The retardation films are single-axial films. The specific angle Θ 1 is one of degree values (15, 75, 105, and 165). In a transmissive type liquid crystal display, a structure of the other panel plate is similar to that of one panel plate and combination to the values (Θ 1, Θ2, Θ3, Θ4 ) is one selected from the group consisting of combinations (15, 75, 165, 105), (75,15,105,165), (105,165,75,15), and (165,105,15,75).

1 . A method of manufacturing a liquid crystal display, the method comprising:
 providing a liquid crystal with a first substrate glass or a second substrate glass to form a liquid crystal layer on the first substrate glass or the second substrate glass;   coupling the first substrate glass with the second substrate glass to interpose the liquid crystal layer between the first substrate glass and the second substrate glass;   forming a first polarizer on an outer side of the first substrate glass, the outer side being opposite to the liquid crystal layer;   forming a first quarter wavelength retardation plate comprising a first half wavelength retardation film and a first quarter wavelength retardation film between the first substrate glass and the first polarizer, wherein the first half wavelength retardation film of a predetermined wavelength is adjacent to the first polarizer, wherein a slow axis of the first half wavelength retardation film makes a specific angle of Θ 1  with a transmissive axis of the first polarizer, wherein the first quarter wavelength retardation film is adjacent to the first substrate glass, wherein a slow axis of the first quarter wavelength retardation film makes a specific angle of Θ 2 =2×Θ 1 ±45 degrees;   forming a second polarizer on an outer side of the second substrate glass, the outer side being opposite to the liquid crystal layer; and   forming a second quarter wavelength retardation plate comprising a second half wavelength retardation film and a second quarter wavelength retardation film between the second substrate glass and the second polarizer, wherein the second half wavelength retardation film of the predetermined wavelength is adjacent to the second polarizer, wherein a slow axis of the second half wavelength retardation film makes a specific angle of Θ 4  with a transmissive axis of the second polarizer, wherein the second quarter wavelength retardation film is adjacent to the second substrate glass, wherein a slow axis of the second quarter wavelength retardation film makes a specific angle of Θ 3  with the transmissive axis of the second polarizer in accordance with the relation equation of Θ 3 =2×Θ 4 ±45 degrees,   wherein a display region of a liquid crystal display comprising the first substrate glass and the second substrate glass is divided into a reflective region and a transmissive region,   wherein in the reflective region, the effective light path difference Δnd of the liquid crystal layer is equal to a quarter of the predetermined wavelength and a reflector is placed on the inner side of the second substrate glass,   wherein in the transmissive region, the effective light path difference Δnd of the liquid crystal layer is equal to a half of the predetermined wavelength, and   wherein the relation equations Θ 2 =(2×Θ 1 )±45 degrees and Θ 3 =(2×Θ 4 )±45 degrees obtain for the reflective region and the transmissive region.   
   
   
       2 . The method of  claim 1 , wherein the predetermined wavelength is 5500 Å. 
   
   
       3 . The method of  claim 1 , wherein the effective light path difference Δnd of the liquid crystal layer is equal to a quarter of the predetermined wavelength and a reflector is placed on an inner side of the second substrate glass. 
   
   
       4 . The method of  claim 1 , wherein the specific angle Θ 1  is one selected from a group consisting of degree values (15, 75, 105, and 165) with limit to an error of 5 degrees and the specific angle Θ 2  is decided by relation equation of Θ 2 =2×Θ 1 +45 degree. 
   
   
       5 . The method of  claim 1 , wherein the retardation films are single-axial films. 
   
   
       6 . The method of  claim 1 , wherein the effective light path difference Δnd of the liquid crystal layer is equal to a half of the predetermined wavelength. 
   
   
       7 . The method of  claim 1 , wherein the transmissive axis of the first polarizer is perpendicular to the transmissive axis of the second polarizer. 
   
   
       8 . The method of  claim 1 , wherein a combination of the values (Θ 1 , Θ 2 , Θ 3 , Θ 4 ) is one selected from a group consisting of combinations (15, 75, 165, 105) and (105, 165, 75, 15). 
   
   
       9 . The method of  claim 1 , wherein the display region is made of pixels having a thin film transistor and a region of the respective pixels is divided into the reflective region and the transmissive region. 
   
   
       10 . The method of  claim 1 , wherein the thickness of the liquid crystal layer is controlled by regional thickness of an organic insulating layer.