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:
Nov. 11, 2008
Filed:
Oct. 27, 2004
Fumihiro Tawa, Kawasaki, JP;
Fumihiro Tawa, Kawasaki, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
A multilayer optical recording medium including a first recording layer for recording or reproducing information by using a first light beam having a center wavelength λ1, a first photochromic layer provided on the first recording layer, and a first optical waveguide layer provided on the first photochromic layer for guiding to the first photochromic layer a second light beam having a center wavelength λ2 different from the center wavelength λ1. The multilayer optical recording medium further includes a second recording layer provided on the first optical waveguide layer for recording or reproducing information by using the first light beam, a second photochromic layer provided on the second recording layer, and a second optical waveguide layer provided on the second photochromic layer for guiding the second light beam to the second photochromic layer. The first and second photochromic layers become transparent to the first light beam by irradiation with light or by application of heat. The reflectance of each of the first and second photochromic layers to the first light beam can be repeatedly increased by irradiation with the second light beam and can be repeatedly decrease to restore the transparent state.