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:
Jun. 24, 2003
Filed:
Nov. 16, 1999
Kiyoshi Tateishi, Tsurugashima, JP;
Kazuo Takahashi, Tsurugashima, JP;
Pioneer Corporation, Tokyo-to, JP;
Abstract
A focus jump moves a focus position of a light beam in a direction perpendicular to the storage medium to the focus position corresponding to a target recording layer so that the light beam is irradiated on the target recording layer. The device includes: a focus position moving unit for moving the focus position of the light beam; a focus error signal detector for detecting a focus error signal based on a variation of a returning light from the storage medium; a feedforward controller for supplying a drive signal to the focus position moving unit to move the focus position of the light beam in an acceleration state in an acceleration control and to move the focus position of the light beam in a deceleration state in a deceleration control; and a position controller for comparing the focus error signal, detected the time of movement of the focus position of the light beam to the target recording layer, with a predetermined target value to generate an error, and for feeding back the drive signal to the focus position moving-unit to reduce the error thereby to control the focus position of the light beam.