ORIENTED FILM FOR LIQUID CRYSTAL DISPLAY ELEMENT

摘要

PURPOSE:To lessen the dependency of a pretilt angle on production conditions and to lessen the dependency of the threshold voltage on frequencies at the high pretilt so as to prevent uneven display by composing an oriented film of a polyimide resin contg. specific constituting units. CONSTITUTION:This oriented film consists of the polyimide resin contg. the constituting units expressed by the formula. In the formula, R<1> denotes 7 to 18C alkyl group; R<2> denotes 1 to 18C alkyl group; R<3> and R<4> denote hydrogen or 1 to 18C alkyl groups; X denotes 1 to 4C alkyl group; a to d denote 0, 1 or 2; Z denotes an arom. hydrocarbon group. The polyimide resin is obtd. by polymerizing a diamine having basic skeleton of a bis-benzoyloxyphenylene type and tetracarboxylic dianhydride. The diamine of the bis- benzoyloxyphenylene is exemplified by 2,2-bis[4-(p-aminobenzoyloxy) phenylene]nonane, etc.