Method for producing viewing angle compensator for liquid crystal display

Claim 1

A method for producing a viewing angle compensator for a liquid crystal display comprising the steps of: (i) applying a coating to a light transmitting substrate having an alignment layer thereon wherein said coating comprises (A) an optically active polyester containing as a constituent a hydrocarbon unit selected from the group consisting of (a) a radical selected from the group consisting of ##STR50## where X is chlorine or bromine, C 1 -C 4 alkoxy, C 1 -C 4 alkyl or phenyl, and k is 0 to 2: (b) polycyclic hydrocarbon units; and (c) aromatic units having a substituent selected from the group consisting of a hydrocarbon group of 3 to 8 carbon atoms, a halogen atom and mixtures thereof, with the proviso that these units exclude the units encompassed by (a); or (B) a composition containing a liquid crystalline polyester which contains said hydrocarbon unit as a constituent and an optically active compound; (ii) heat treating the applied coating of step (i) at a temperature higher than the glass transition temperature of the polyester to form a cholesteric structure; and (iii) cooling said heat-treated coating to a temperature lower than said glass transition temperature to solidify said cholesteric structure, thereby producing a viewing angle compensator wherein said compensator has a product (Δn·p), calculated by multiplying birefringence (Δn) by pitch length (p) of the heat-treated coating, of less than 600 nm.

Claim 2

A method for producing a viewing angle compensator for a liquid crystal display comprising the steps of: (i) applying a coating to a light transmitting substrate having an alignment layer thereon wherein said coating comprises (A) an optically active polyester containing as a constituent a hydrocarbon unit selected from the group consisting of (a) a radical selected from the group consisting of ##STR50## where X is chlorine or bromine, C 1 -C 4 alkoxy, C 1 -C 4 alkyl or phenyl, and k is 0 to 2: (b) polycyclic hydrocarbon units; and (c) aromatic units having a substituent selected from the group consisting of a hydrocarbon group of 3 to 8 carbon atoms, a halogen atom and mixtures thereof, with the proviso that these units exclude the units encompassed by (a); or (B) a composition containing a liquid crystalline polyester which contains said hydrocarbon unit as a constituent and an optically active compound; (ii) heat treating the applied coating of step (i) at a temperature higher than the glass transition temperature of the polyester to form a cholesteric structure; and (iii) cooling said heat-treated coating to a temperature lower than said glass transition temperature to solidify said cholesteric structure, thereby producing a viewing angle compensator wherein said compensator has a product (Δn·p), calculated by multiplying birefringence (Δn) by pitch length (p) of the heat-treated coating, of less than 600 nm.