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:
Feb. 18, 1992
Filed:
Aug. 09, 1989
Katsuya Watanabe, Osaka, JP;
Mitsuro Moriya, Neyagawa, JP;
Shinichi Yamada, Hirakata, JP;
Masayuki Shibano, Izumisano, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
In an apparatus which focuses a light beam on a rotating recording medium in order to record and/or reproduce information, the light beam on the recording medium is focus controlled so that a prescribed focusing condition is accomplished. By storing a relation between a target position of focus control and the amplitude of a reproduced signal and by obtaining an optimum target position of focus control is accordance with such stored information, the target position of the focus control can be precisely and quickly adjusted, thereby properly controlling the light beam to be focused on the recording medium.