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:
Oct. 30, 1995
Filed:
Jan. 16, 1995
Applicant:
Inventors:
Assignee:
Sony Corporation, Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
369 4429 ; 369 4435 ; 369 58 ;
Abstract
An optical disc reproducing apparatus can play multiple types of discs. The apparatus biases a focusing error signal based on the disc type. An analyzer receives reflected light of a light beam irradiated from an optical pick-up to a disc. A focus error signal is generated based on the signal supplied the analyzer. A switch selectively provides one of first and second bias voltages. A control controls which of the first and second bias voltages the switch provides based on the type of disc. The bias voltage is added to the focus error signal. An object lens of the optical pickup is driven based on the focus error signal with the bias voltage added.