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:
Dec. 15, 1992
Filed:
May. 22, 1991
Applicant:
Inventors:
Assignee:
Pioneer Electronic Corporation, Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
369 4432 ; 369 4435 ; 369 4441 ;
Abstract
In the photo-detecting device, the light receiving surface of the light receiving element is divided into four sections A, B, C, D in the direction of tracking. To detect any tracking error, the quantities of received light on these four light receiving sections are used to calculate {(A+B)-(C+D)}-.alpha.{(A-B)+(C-D)}, where .alpha. is an adjustable value such as a variable resistance. Since this provides a true tracking error which does not include a dc offset, it is possible to make a correct adjustment of the tracking.