Patent ID: 8470413

Claim:
A negative C-type retardation compensator for a liquid crystal display comprising: 1) a transparent base layer; and 2) a polyarylate coating layer which is layered on the transparent base layer and has a thio group or a sulfur oxide group in a polymer main chain thereof, wherein the polyarylate having the thio group or the sulfur oxide group in the polymer main chain is represented by Formula 1: wherein, a, b, c, and d are each independently an integer of 0, or 1 to 4, m and n are molar fractions, m+n=1, 0≦m≦1, and 0.001≦n≦0.4, R 1 and R 2 are each independently a halogen, a nitrile group, a C 1 to C 12 alkoxy group, a C 6 to C 12 arylalkyl group, a C 6 to C 12 aryl group, or a C 1 to C 12 acyl group, R 3 and R 4 are each independently a halogen, a nitrile group, a C 1 to C 12 alkyl group, a C 1 to C 12 alkoxy group, a C 6 to C 12 arylalkyl group, a C 6 to C 12 aryl group, or a C 1 to C 12 acyl group, W 1 is a direct bond, a C 1 to C 30 alkylidene group, a C 2 to C 30 alkylene group, a C 3 to C 30 cycloalkylidene group, a C 3 to C 30 cycloalkylene group, a C 2 to C 30 phenyl-substituted alkylene group, a carbonyl group, NR, PO 2 , an oxygen, wherein R is a hydrogen, a C 1 to C 12 alkyl group, a C 6 to C 12 arylalkyl group, or a C 6 to C 12 aryl group, W 2 is a thio group or a sulfur oxide group, wherein in the polyarylate coating layer, a retardation in a thickness direction which is defined by Equation 1 is negative, and an absolute value of the retardation is 10 nm or more: R th = ( n z - n x + n y 2 ) × d [ Equation ⁢ ⁢ 1 ] wherein, n x is a refractive index which is the highest in a surface direction of the coating layer, n y is the refractive index of the direction perpendicular to the direction of n x in the surface direction of the coating layer, n z is the refractive index of the direction perpendicular to an n xy plane, and d is a thickness of the coating layer.