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:
Oct. 16, 2007
Filed:
Jan. 31, 2003
Applicant:
Hiroaki Shimozono, Yokohama, JP;
Inventor:
Hiroaki Shimozono, Yokohama, JP;
Assignee:
Asahi Glass Company, Limited, Tokyo, JP;
Primary Examiner:
Int. Cl.
CPC ...
G11B 7/095 (2006.01);
U.S. Cl.
CPC ...
Abstract
An objective lens in which a first wavelength is used in reading a first optical disk, a second wavelength is used in recording or reading a second optical disk, and a phase shifter provided with annular step portions having a center coincident with an optical axis is formed in a single surface of the objective lens, the phase shifter producing a phase difference with respect to light having the first wavelength and light having the second wavelength, is presented. The objective lens can read well both a CD and a DVD.