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. 20, 1993
Filed:
Apr. 02, 1992
Fumio Matsui, Saitama, JP;
Makoto Okano, Saitama, JP;
Tatsuro Sakai, Saitama, JP;
Satoru Tanaka, Saitama, JP;
Shuichi Yanagisawa, Saitama, JP;
Pioneer Electronic Corporation, Tokyo, JP;
Abstract
A write once read many type optical disc comprises a light transmissive substrate having a tracking groove formed therein, a light absorbing layer disposed on a surface of the substrate on which the tracking groove is formed, and a light reflection layer disposed on the light absorbing layer, wherein an RMI value defined by the following formula is not lower than 0.22: RMI value=(I.sub.l -I.sub.g)I.sub.o, wherein I.sub.l denotes an electric potential at a land portion, I.sub.g denotes an electric potential at a groove portion, and I.sub.o denotes an electric potential at a mirror surface portion. When the write once read many type optical disc is caused to have a structure as described above, there may be provided the write once read many type optical disc having a good playability, i.e., the optical disc wherein the TE level may be provided assuredly on the basis of a value obtained from one beam.