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.

Date of Patent:
Jun. 23, 1992

Filed:

Jan. 16, 1990
Applicant:
Inventors:

Katsuharu Sato, Saitama, JP;

Naoharu Yanagawa, Saitama, JP;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
369112 ; 369 4414 ;
Abstract

An optical head wherein a required astigmatism can be obtained readily to facilitate production thereof and the linear distance between a face of an information record medium and a light receiving element is reduced to reduce the overall size and weight of the optical head. The optical head comprises a prism having a parallelogram shape in side elevation. The prism has a reflecting/transmitting face extending at an angle of about 45 degrees with respect to an optical axis to the information record face for reflecting light from a light source toward the information record face, first and second reflecting faces extending perpendicularly to the optical axis for successively reflecting light transmitted thereto through the transmitting face, and a transmission face extending in parallel to the reflecting/transmitting face. Light emerging from the transmitting face of the prism is received and converted into an electrical signal by a light receiving element.


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