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:
Aug. 25, 1998
Filed:
Dec. 02, 1996
Masayuki Koyama, Tokorozawa, JP;
Pioneer Electronic Corporation, Tokyo, JP;
Abstract
An optical pickup unit that is capable of reproducing information from two types of recording media whose thickness characteristics differ from each other and can reduce heat generated due to DC offsets generated in a focus actuator, that can suppress a change of an aberration of an objective lens due to the generated heat, and that can suppress a change of its pickup performance includes an objective lens; a lens holder for holding the objective lens; a supporting member for supporting the lens holder; an error signal generator for generating a focus error signal based on the reflected light of the light beam from the recording surface upon which the light beam is being impinged; and a focus controller for actuating and controlling the objective lens such that the light beam is converged on the information recording surface based the error signal; the supporting member supporting the lens holder such that a dead-load suspension position of the lens holder is positioned at a position where an absolute value of an offset component of the error signal obtained in controlling the focus for the first recording medium is equal to an absolute value of an offset component of the error signal obtained in controlling the focus for the second recording medium.