Patent ID: 7163723

Claim:
A retardation film comprising a film in which a liquid crystal comprising a cellulose derivative, wherein the cellulose derivative is a cellulose derivative that a hydroxyl group of a hydroxyalkyl cellulose is substituted with an aliphatic unsaturated double bond-containing acyl group having from 4 to 10 carbon atoms or a tertiary acyl group having from 4 to 10 carbon atoms and further a hydroxyl group of the hydroxyalkyl cellulose, which is not substituted with the said acyl group, may be substituted with an acyl group having from 1 to 10 carbon atoms, which may contain an aromatic group, or an alkyl group having from 1 to about 10 carbon atoms, as a liquid crystal compound (hereinafter referred to as a cellulose derivative liquid crystal) is oriented in a stretching direction or a shearing direction by a uniaxially or biaxially stretching method, a shearing method or a slide shearing method.