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:
Jul. 16, 1991
Filed:
Apr. 13, 1990
Applicant:
Inventor:
Ichiro Morishita, Iwanuma, JP;
Assignee:
Alps Electric Co., Ltd., Tokyo, JP;
Attorneys:
Primary Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
369112 ;
Abstract
An optical apparatus of an optical pickup including a semiconductor laser, a collimate lens to obtain a parallel light from a laser beam emitted from said semiconductor laser, an objective for collecting on a recording surface of an optical disk the parallel light obtained through the collimate lens, and a light receiving element for detecting a reflection light reflected on the recording surface of the optical disk wherein a numeric aperture NA of said collimate lens is set as 0.14<NA<0.2.