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:
Apr. 11, 1989
Filed:
Aug. 27, 1987
Applicant:
Inventors:
Assignee:
Alps Electric Co., Ltd., , JP;
Attorneys:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G02B / ;
U.S. Cl.
CPC ...
350432 ;
Abstract
An ojective lens for use in an optical pickup that is employed in a compact disk player, for example. The objective lens has a first aspherical surface on which parallel light rays impinge and a second spherical surface that faces the disk. The aspherical surface lies in a meridian plane of a cartesian coordinate system. The X-axis of this coordinate system is taken on the optical axis, the Y-axis is taken at the apex of the aspherical surface. The aspherical surface which is axially symmetrical is given by