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:
Jul. 25, 1995
Filed:
Mar. 08, 1994
Applicant:
Inventors:
Assignee:
Pioneer Electronic Corporation, Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
3692752 ; 3692755 ; 369283 ; 369284 ; 369285 ; 36944437 ; 428 644 ;
Abstract
An optical disc has a recording film with information recorded thereon, and a photochromic material film provided adjacent the recording film. The photochromic material film is made of a photochromic material. The photochromic material has a first state irradiated with reading light having a first wavelength. In the first state, the transmittance of the material is increased so as to enable reading of the recorded information. The photochromic material further has a second state irradiated with auxiliary light having a second wavelength, where the transmittance becomes low so as to disable the reading of the recorded information.