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:
May. 04, 1982
Filed:
Dec. 16, 1980
Tomio Yoshida, Katano, JP;
Michiyoshi Nagashima, Ikoma, JP;
Shunji Harigae, Neyagawa, JP;
Makoto Ichinose, Moriguchi, JP;
Noboru Wakami, Osaka, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
In an optical recording device in which the writing laser light beam is focused to a small spot on a disk which is coated with a photosensitive medium and spins at a predetermined velocity so that the data are recorded in terms of variable density or surface irregularities, the forward DC current applied to a semiconductor laser is varied depending upon the radius position of the writing laser beam spot on the disk but the AC current which is superposed on the DC current and rises or drops above or below the DC current level by a predetermined amplitude depending upon the data to be recorded is maintained constant regardless of the radius position of the writing laser beam spot, whereby the duty ratio can be maintained constant regardless of the distance from the center of the disk of a selected recording track.