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:
Aug. 18, 1992
Filed:
Nov. 08, 1990
Shinichi Yamada, Hirakata, JP;
Mitsuro Moriya, Ikoma, JP;
Masayuki Shibano, Izumisano, JP;
Hiroyuki Yamaguchi, Hirakata, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
A method of and an apparatus for setting into operation a focusing control for bringing a focal point of a beam onto a recording surface of an optical disk such that the beam reproduces signals from the recording surface, in which a relative velocity between the focal point and the recording surface is detected on the basis of an output of a focusing error detection device for detecting a gap between the focal point and the recording surface and velocity of a displacement device for driving the focal point in a direction perpendicular to the recording surface is controlled on the basis of the detected relative velocity such that focusing control can be stably set into operation by starting focusing control after controlling the relative velocity.