Optical compensation film for liquid crystal displays and related inventions

摘要

A cellulose acylate-based optical compensation film (A) for liquid crystal displays (LCD's) contains (as additive) at least one rod-shaped liquid crystalline poly-p-phenylene compound (I), having at least two aromatic rings. A cellulose acylate-based optical compensation film (A) for liquid crystal displays (LCD's) contains (as additive) at least one poly-p-phenylene compound of formula (I). R 1> : 1-12C n-alkyl or 1-12C n-alkoxy (both optionally having one or more CH 2groups replaced by O, S, CO, COO, OCO, OCOO, NR 4>, CONR 4>or NR 4>CO (provided that O and/or S atoms are not directly bonded together) and optionally substituted by one or more F); R 2> : CN, F or as for R 1>; R 4> : H or 1-7C alkyl; ring A : p-phenylene substituted by (L) a; or trans-1,4-cyclohexylene; Z 1>- Z 4> : COO, OCO, CONR 4>, NR 4>CO, CH 2O, OCH 2, CH 2S, SCH 2 or bond; L : H or F; or one L group can also be Cl; a, b, c, d : 0-2; e : 0 or 1. Independent claims are included for: (1) the use of (I) for the production of the film (A), by addition of (I) during the production of (A); and (2) the production of (A) by incorporation of (I) in a mixture for use in a film forming procedure. POLYMERS - Preferred Composition: The film (A) is based on cellulose acetate-propionate and/or cellulose acetate. (I) is contained in (A) at 0.5-10 (especially 2-6) wt. %. (A) has a thickness of 20-150 (especially 30-100) microns; an in-plane retardation value (Ro) of 30-70 (especially 40-60) nm; and an out-of-plane retardation value (Rth) of 100-160 (especially 120-140) nm or 190-250 (especially 210-230) nm. Preferred Process: (A) is obtained by a solution casting procedure. After casting and drying, the film is oriented monoaxially (preferably with holding perpendicular to the orientation direction) or especially biaxially. [Image].