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:
Jan. 13, 1987
Filed:
Jan. 23, 1985
Applicant:
Inventor:
Yoshiyuki Tsukai, Saitama, JP;
Assignee:
Pioneer Electronic Corporation, Tokyo, JP;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01J / ; G11B / ;
U.S. Cl.
CPC ...
250201 ; 369 46 ;
Abstract
An apparatus for reading optically recorded data from a disk in which diffracted light beams, which otherwise would be applied to light-detecting elements and which are of higher order than the positive and negative first-order diffracted light beams, are eliminated and only a zeroth-order diffracted light beam is applied to the light-detecting elements. Thereby, a tilt control signal is produced whereby a tilt servo operation can be carried out with a high accuracy. Several different structural arrangements are disclosed for achieving the desired blocking of the higher-than-zeroth-order diffracted light beams.