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:
Jan. 02, 2018
Filed:
Apr. 01, 2014
Mitsui Chemicals, Inc., Minato-ku, Tokyo, JP;
Kenichi Fukukawa, Tokyo, JP;
Masaki Okazaki, Chiba, JP;
Yoshihiro Sakata, Ichikawa, JP;
Tatsuhiro Urakami, Ichihara, JP;
Atsushi Okubo, Tokyo, JP;
MITSUI CHEMICALS, INC., Tokyo, JP;
Abstract
The present invention addresses the problem of providing a high-transparency polyimide film in which the thickness-direction phase difference Rth is kept within a predetermined range. The present invention also addresses the problem of providing a polyamic acid and a varnish used to obtain the polyimide film. In order to overcome the aforementioned problem, the present invention is a polyimide film containing a polyimide obtained by bringing about a reaction between a tetracarboxylic dianhydride and a diamine, the polyimide film having (a) a thickness-direction phase difference Rth of −5 to 100 nm per 10 μm of thickness, (b) a transmittance of 80% or more with respect to light having a wavelength of 400 nm, (c) a haze of 3% or less, and (d) a glass transition point of 250° C. or higher.