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:
Mar. 24, 1998
Filed:
Mar. 30, 1995
Hiroyuki Yamaguchi, Hirakata, JP;
Mitsuro Moriya, Ikoma, JP;
Osamu Yamaguchi, Hirakata, JP;
Shin-ichi Yamada, Katano, JP;
Toshiyuki Kinou, Kofu, JP;
Yoshihiro Kanda, Osaka, JP;
Matsushita Electric Industrial Co., Ltd., Kadoma, JP;
Abstract
A focusing control apparatus is provided for controlling focusing of a light beam on a recording medium. The apparatus includes a control mechanism for maintaining the focusing state of the light beam on the recording medium by moving a focus mechanism based on a comparison between an output signal indicative of the focusing state and a target value. The apparatus further includes a target value setting circuit for setting the target value at a first level when the light beam is irradiated on the land track portions of the recording medium; and for setting the target value at a second level when the light beam is irradiated on the groove track portions.