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:
Feb. 27, 2018
Filed:
Apr. 01, 2014
Mitsui Chemicals, Inc., Minato-ku, Tokyo, JP;
Tatsuhiro Urakami, Chiba, JP;
Masaki Okazaki, Chiba, JP;
Kenichi Fukukawa, Tokyo, JP;
Yoshihiro Sakata, Ichikawa, JP;
Atsushi Okubo, Tokyo, JP;
MITSUI CHEMICALS, INC., Minato-Ku, Tokyo, JP;
Abstract
The present invention addresses the problem of providing: a polyimide film that has a small phase difference in the thickness direction and has a low coefficient of linear thermal expansion; and a polyamic acid and varnish to obtain the same. In order to solve this problem, the present invention provides a polyimide film which comprises polyimide that is produced by reacting a diamine component and a tetracarboxylic dianhydride component, the polyimide film having a coefficient of linear thermal expansion of 35 ppm/K or less over a temperature range of 100 to 200 DEG C, an absolute value of phase difference in the thickness direction of 200 nm or less per 10 μm thickness, a glass transition temperature of 260 DEG C or more, and a total light transmittance of 85% or more.