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:
Apr. 13, 2004
Filed:
Jan. 30, 2002
Masashi Kubota, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
In case of pulling a focusing servo in a recording surface of an optical disk , the focusing servo is pulled in a substrate surface of the optical disk , thereafter, a focusing servo pull-in position is allowed to transfer to the recording surface of the optical disk by means of a focusing jump control circuit , whereby a focusing servo pull-in operation is made upon the recording surface , while an objective lens retreating control circuit outputs a control signal in a direction along which the objective lens is allowed to go away from the optical disk for a predetermined time, and then, another control signal in a direction along which the objective lens is allowed to be close to the optical disk for a predetermined time in the case when an abnormal focusing servo pull-in operation was detected.