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:
Mar. 09, 1999
Filed:
Sep. 24, 1997
Applicant:
Inventor:
Hiroshi Suganuma, Ibaragi, JP;
Assignee:
Sony Corporation, Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G02B / ;
U.S. Cl.
CPC ...
359717 ; 359719 ;
Abstract
A object of the present invention is to provide an objective lens that two non spherical surfaces are combined and a numeral aperture is more than 0.7, and to provide an optical pick-up apparatus which can be used for an optical recording medium having high information recording density by using this objective lens. There is disclosed that a first surface is a rotating ellipse surface (a cone constant k: -1.ltoreq.k<0), and curvature of the first surface, glass materials (refractive index) of a first lens 1 and a main plane interval d of the total of combination of two lenses are properly established to satisfy the fixed relational expression.