| 摘要 |
<p>#CMT# #/CMT# 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. #CMT# : #/CMT# 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. #CMT#[Image]#/CMT# #CMT#USE : #/CMT# The optical compensation films (A) are incorporated between the polarization plates and the liquid crystalline cell of LCD's, to prevent undesirable discoloration of the displayed image (due e.g. to the inherent double refraction of the liquid crystalline layer) and to increase the angle of observation from which an image of acceptable contrast is visible. Polarization plates including (A) and LCD's (preferably vertically aligned (VA) LCD's) including at least one film (A) (specifically one or two films (A)) are claimed. Also claimed are the production of the (I)-containing polarization plates, by applying (I) to a polarization membrane (or its protective layer), specifically by lamination; and the production of the (I)-containing LCD's by using at least one polarization plate to which (I) is applied, specifically by lamination. #CMT#ADVANTAGE : #/CMT# Addition of (I) to (A) provides retardation values within the target values, in both the in-plane and out-of-plane directions ((Ro) and (Rth)). The retardation values can be adjusted accurately and flexibly, by selection of the nature and concentraton of (I) and by orientation of the films; and the obtained values are permanently retained. (I) are compatible, over a wide concentration range, with the other components of (A) (both during production and in the final product); cause no undesirable discoloration or turbidity; and show good solubility in solvents used for film production. #CMT#SPECIFIC COMPOUNDS : #/CMT# 7 Compounds (I) are specified in the claims, e.g. 4-butyl-2'-fluoro-4''-ethyl-p,p'-terphenyl (Ia) (designated'PGP-2-5'), 4-propyl-2'-fluoro-4''-ethyl-p,p'-terphenyl, 4-pentyl-2'-fluoro-4''-ethyl-p,p'-terphenyl, 4,4''-dipropyl-2'-fluoro-4''-p,p'-terphenyl and 4-propyl-2',3'-difluoro-4''-ethoxy-p,p'-terphenyl. #CMT#[Image]#/CMT# #CMT#EXAMPLE : #/CMT# Portions of a lacquer comprising a 16 wt. % solution of triacetyl cellulose (degree of acetylation 60.8%) and triphenyl phosphate (plasticizer; 10 wt. % based on solids) in dichloromethane-methanol (95:5 by weight) were treated with 2.5 wt. % or 5 wt. % (based on solids) of various rod-form liquid crystalline additives, made up to an overall solids content of 16 wt. %, deaerated and cast to give (after drying overnight at 80[deg] C) films of thickness ca. 80 microns. A film of this type, containing 2.5 wt. % 4-butyl-2'-fluoro-4''-ethyl-p,p'-terphenyl (Ia) (designated'PGP-2-5') as the additive, was asymmetrically oriented (1.2 x 1, machine direction x transverse direction; orientation factor 1.1). The oriented film had a retardation value (Ro) in the plane direction of 62 nm and a retardation value (Rth) in the thickness direction of 121 nm, both of these values being in the target region.</p> |
