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. 07, 1998
Filed:
Feb. 27, 1996
Applicant:
Inventors:
Akio Yamakawa, Kanagawa, JP;
Kamon Uemura, Tokyo, JP;
Assignee:
Sony Corporation, Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11B / ; G02B / ;
U.S. Cl.
CPC ...
369 99 ; 369 4437 ; 369112 ; 369 4423 ;
Abstract
An objective lens having at least two regions of different numerical apertures is configured for focusing a light beam through the regions of the different numerical apertures on two different signal recording surfaces of at least two optical discs having light transmitting layers of different thicknesses. Since the objective lens is integrally formed by at least two lens portions, a light beam outgoing from a common light source is focused on signal recording surfaces of at least two optical discs having the light transmitting layers of different thicknesses.