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. 07, 1992
Filed:
May. 21, 1990
Osamu Ito, Tsukaguchihonmachi, JP;
Masaharu Ogawa, Tsukaguchihonmachi, JP;
Kyosuke Yoshimoto, Tsukaguchihonmachi, JP;
Kunimaro Tanaka, Tsukaguchihonmachi, JP;
Teruo Furukawa, Tsukaguchihonmachi, JP;
Yoshiki Nakajima, Tsukaguchihonmachi, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
An optical disc having a plurality of information tracks, each information track having a servo field including a pair of wobbled pits and a clock pit. The distance between one of the wobbled pits and the clock pit in each servo field is selected such that the optical disc includes at least three different types of servo field. These differnt types of servo field appear in a predetermined sequence for every one or more contiguous information tracks. A driving apparatus for driving such an optical disc has a direction detecting circuit for detecting the moving velocity of a movable portion of an optical head, and a speed detecting circuit for detecting the relative velocity of the movable portion.