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:
Oct. 15, 1985
Filed:
Oct. 07, 1982
Applicant:
Inventors:
Assignee:
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
369275 ; 369109 ;
Abstract
An optical disc for optical recording, retrieving and erasing of informations. The phase difference .psi. of reflected light produced by the tracking groove in the form of convexity or protrusion of concavity or groove and the change .DELTA..psi. in the phase difference caused by a recording in a recording film are selected in relation to each other to provide a stable detection signal for tracking, thereby to permit a highly accurate tracking on the optical disc carrying information at a high density.