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. 17, 1984
Filed:
Feb. 03, 1982
Junichi Shimada, Ibaraki, JP;
Yoshinobu Mitsuhashi, Ibaraki, JP;
Keisuke Kikuchi, Ibaraki, JP;
Kenjiro Sakurai, Tokyo, JP;
Agency of Industrial Science & Technology, Tokyo, JP;
Ministry of International Trade & Industry, Tokyo, JP;
Abstract
An optical memory playback apparatus is constructed so that a single longitudinal mode of laser beam emitted from a self-coupling semiconductor laser element is projected through an optical system onto an information recording medium and the laser beam reflected by the information recording medium is returned through the same optical system back to the semiconductor laser element. In addition, the apparatus interposes a spatially uneven phase plate in the optical system, whereby the longitudinal mode of emission of the semiconductor laser element is converted into a random multi-mode at all times and, consequently, the reproduction of information from the information recording medium is effected by detecting the variation in the intensity of output or terminal voltage of the semiconductor laser element which occurs in conformity with the variation in the intensity of the reflected laser beam.