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:
Sep. 22, 1998
Filed:
Jun. 09, 1994
Nobuo Akahira, Yawata, JP;
Kenichi Nagata, Mino, JP;
Eiji Ohno, Hirakata, JP;
Kenichi Nishiuchi, Moriguchi, JP;
Noboru Yamada, Hirakata, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
An optical information recording medium, which includes a substrate, and a recording thin film layer provided on the base material and adapted to form variation in an amount optically detectable by absorbing at least laser light so as to record information by partially varying the recording thin film layer and to reproduce the information by optically detecting the variation amount. The optical information recording medium further includes transparent layers each provided in contact with the recording thin film layer, and each of the transparent layers has optical thickness in which, in at least two different wavelengths .lambda., integral multiple of .lambda./2 is added to the thickness giving the large laser light absorption and large optical variation amount, respectively. More specifically, the optically detectable amount is of a reflectance factor variation, and in the different wavelengths .lambda.1 and .lambda.2, with respect to the thicknesses d1 and d2 of the transparent layers which give the optical characteristic more than 60% in the absorption, and more than 20% in the reflectance factor variation, the thickness of each transparent layer is arranged to be the thickness d having relation as represented by a following equation.