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. 21, 1990
Filed:
Jan. 25, 1988
Applicant:
Inventors:
Assignee:
NEC Corporation, Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11B / ; G11B / ;
U.S. Cl.
CPC ...
369 4411 ; 369 13 ; 369110 ; 369112 ; 360114 ;
Abstract
A magneto-optical head for reading information from a recording medium, the head having a laser-based optical system that comprises two light paths, a first path from the source to and continuing through or reflecting from medium and a second path in a different direction which directs light from the medium to a detector. The second path includes a dual prism multiplying element (Wollaston prism) for dividing the reflected beam into three distinctly oriented beams, and a multi division photodetector for detecting a servo signal by the astigmatism method and an information signal by a differential polarization method.