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:
Apr. 13, 2004
Filed:
Feb. 19, 2002
Tokuyama Corporation, Yamaguchi, JP;
Abstract
A chromene compound which develops yellow to red color, a high color density and a little initial color and which, when used in combination with an existing photochromic compound that exhibits blue color so as to develop a neutral tint, maintains uniformity in the color tone at the time of developing color or fading color, or exhibits a very large color fading rate. The chromene compound has a naphthopyran cyclic skeleton, and is expressed by, for example, the following formula in which a substituent such as substituted amino group or morpholino group is bonded to the sixth position of the naphthopyran ring through a nitrogen atom, and two aryl groups having a particular substituent are bonded to the third position thereof,