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:
Nov. 24, 1987
Filed:
Apr. 03, 1986
Applicant:
Inventors:
Akira Nakamura, Kanagawa, JP;
Hiroshi Oinoue, Tokyo, JP;
Tomoyuki Ishida, Tokyo, JP;
Kenji Shintani, Tokyo, JP;
Assignee:
Sony Corporation, Tokyo, JP;
Attorneys:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11B / ; G01J / ;
U.S. Cl.
CPC ...
250201 ; 369 44 ;
Abstract
In an optical head having a plate-like half mirror functioning both as a beam splitter and for producing an astigmatism usable in detecting a focusing error, an optical element is provided for correcting a coma introduced by the half-mirror. Such optical element for correcting coma desirably includes a plate-like element inclined oppositely to the plate-like half mirror in respect to an optical axis of the head.