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:
Oct. 12, 1993
Filed:
Jun. 02, 1992
Hitoshi Taniguchi, Tsurugashima, JP;
Fumio Matsui, Tsurugashima, JP;
Tsuneki Okazaki, Okayama, JP;
Masaaki Hayami, Okayama, JP;
Pioneer Electronic Corporation, Tokyo, JP;
Abstract
A rewritable photochromic optical disk comprises a photochromic recording layer made of a dibenzothienyl ethene derivative, 1,2-di(2-cyano-3-benzothienyl)-1,2-dicyanoethene capable of assuming first and second states, the first state with a first absorption band transforming into the second state with a second absorption band by irradiating a first light beam of a first wavelength, and the second state transforming into the first state by irradiating a second light beam of a second wavelength in the second absorption band. This rewritable photochromic optical disk has a stability in the repeated recording and erasing information and a high thermal stability and capable of storage of information extended over a long period of time, in accordance with its higher quantum yield than that of the conventional dibenzothienyl ethene derivative so that the achromatic reaction takes place by irradiation of a low power laser beam.