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. 24, 2006
Filed:
Jul. 01, 2005
Kenichi Hayashi, Nagano, JP;
Kenichi Hayashi, Nagano, JP;
NIDEC Sankyo Corporation, Nagano, JP;
Abstract
According to the present invention, there is provided an objective lens for an optical head device which condenses two or more laser beams having wavelengths corresponding to two or more optical recording mediums having different thicknesses of transparent substrates on recording surfaces of the optical recording mediums via one optical condensing system to record information on the recording surfaces and/or reproduce the information on the recording surfaces, the objective lens comprising: a refractive surface including: a middle region which is formed in a middle portion of the refractive surface centering on an optical axis of the objective lens and which is used with respect to all of the optical recording mediums; one or more peripheral regions which are concentrically formed outside the middle region; and an aperture limiting ring band which is concentrically formed between the middle region and the peripheral region or between the peripheral regions.