The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 11, 2025
Filed:
Dec. 24, 2020
Osaka Gas Chemicals Co., Ltd., Osaka, JP;
OSAKA GAS CHEMICALS CO., LTD., Osaka, JP;
Abstract
A retardation film includes a polyester-series resin exhibiting a negative orientation birefringence and a forward wavelength dispersibility in retardation in combination with a polyamide-series resin exhibiting a positive orientation birefringence and a flat dispersibility in retardation. The polyester-series resin may contain a constitutional unit having a fluorene-9,9-diyl group, and the polyamide-series resin may contain a constitutional unit having an alicyclic skeleton. The polyester-series resin may contain at least one constitutional unit selected from a fluorenedicarboxylic acid unit (A1) containing a unit of the formula (1) and a fluorenediol unit (B1) containing a unit of the formula (2): wherein Rand Reach represent a substituent; k and m each denote an integer of 0 to 8; X, X, X, and Xeach represent a hydrocarbon group; Aand Aeach represent an alkylene group; n1 and n2 each denote an integer of not less than 0. The retardation film has both a high retardation expression and a reciprocal wavelength dispersibility.