Active matrix type liquid crystal display

Abstract

Disclosed is an in-plane switching active matrix type liquid crystal display with greater improvements on color shifting and contrast. The liquid crystal display comprises an in-plane switching type liquid crystal display panel having an active device substrate, an opposing substrate and a liquid crystal layer held sandwiched between the active device substrate and the opposing substrate, a first polarizer laid out on one side of the liquid crystal display panel, a second polarizer laid out on the opposite side of the liquid crystal display panel, first to third optical compensators placed in order between the liquid crystal display panel and the first polarizer, and a fourth optical compensator placed between the liquid crystal display panel and the second polarizer. As the first to fourth optical compensators are provided to compensate for retardation of the liquid crystal layer and retardation of the polarizers, black stretching does not occur even when observation is made from any viewing angle, and a reduction in contrast does not occur. Nor does color shifting occur at the time of displaying black.

1 .- 43 . (canceled)  
   
   
       44 . A liquid crystal display comprising: 
 an in-plane switching type liquid crystal display panel having an active device substrate, an opposing substrate and a liquid crystal layer held sandwiched between said active device substrate and said opposing substrate;    a first polarizer provided on one side of said liquid crystal display panel;    a second polarizer provided on the other side of said liquid crystal display panel; and    an optical compensator provided at either between said liquid crystal display panel and said first polarizer or between said liquid crystal display panel and said second polarizer, wherein said liquid crystal layer has positive refractive-index anisotropy and is aligned in a direction parallel to said substrate, the absorption axes of said first and second polarizers are perpendicular to each other in a direction parallel to said substrate, one of the absorption axes is placed parallel to the alignment direction of said liquid crystal layer, and said optical compensator has two-axis refractive-index anisotropy, and the optical axes thereof are parallel to the alignment direction of said liquid crystal layer, perpendicular to the alignment direction of said liquid crystal layer on the plane of said substrate and perpendicular to the plane of said substrate.    
   
   
       45 . A liquid crystal display according to  claim 44 , wherein said optical compensator has two-axis refractive-index anisotropy, and the optical axes thereof are parallel to the alignment direction of said liquid crystal layer, perpendicular to the alignment direction of said liquid crystal layer on the plane of said substrate and perpendicular to the plane of said substrate, and relationships of nx>ny and nx>nz are established when it is assumed that the refractive indexes on the optical axes are nx, ny and nz.