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:
Sep. 23, 2003
Filed:
Jan. 14, 2000
Katsuhiro Koike, Tsurugashima, JP;
Pioneer Corporation, Tokyo, JP;
Abstract
An aspherical objective lens and its manufacturing method are disclosed which allows for forming an optical spot with fewer side lobes on optical discs having a continuous lens plane and substrates different in thickness. The aspherical objective lens is characterized by converging first and second beams of light of first and second wavelengths individually on a first optical disc having a first substrate thickness and on a second optical disc having a second substrate thickness greater than the first substrate thickness at approximately a valid first numerical aperture and a second numerical aperture smaller than the first numerical aperture, respectively. A difference between average values of variations in wavefront aberration corresponding to an inner circumference portion and outer circumference portion, when the first beam of light converges on the first optical disk of the first substrate thickness, is approximately equal to one wavelength of a beam of light of the first wavelength.