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:
May. 02, 2000
Filed:
Oct. 24, 1997
Applicant:
Inventors:
Kenji Yamamoto, Tokyo, JP;
Isao Ichimura, Kanagawa, JP;
Fumisada Maeda, Tokyo, JP;
Toshio Watanabe, Kanagawa, JP;
Kiyoshi Ohsato, Chiba, JP;
Assignee:
Sony Corporation, Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11B / ; G02B / ;
U.S. Cl.
CPC ...
369112 ; 369 4423 ; 369 4432 ; 359365 ; 359796 ;
Abstract
An objective lens having a doublet structure and a number of apertures of 0.7 or more and an optical pickup apparatus having the objective lens to be adaptable to a optical recording medium having a high information recording density, the objective lens being structured such that at least one side is formed into a aspheric surface and the lens elements are made of low-diffusion glass having an Abbe's number of 40 or greater.