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:
Dec. 20, 2011
Filed:
Oct. 28, 2010
Naoki Yamagata, Tokyo, JP;
Satoshi Inoue, Saitama, JP;
Shuichi Takeuchi, Saitama, JP;
Hoya Corporation, Tokyo, JP;
Abstract
An optical system of an optical pick-up including a resin coupling lens and a resin objective lens with NA larger than 0.8, wherein, magnification β satisfies a condition: −0.13<β<−0.08, a focal length f of the objective lens satisfies a condition: 1.15<f<1.50, the objective lens has an annular zone structure on at least one surface of the objective lens, and the annular zone structure has a plurality of annular zones and has steps each of which extends in a direction of an optical axis of the objective lens and is formed at a boundary between adjacent ones of the plurality of annular zones to cause a predetermined optical path length difference between a light beam passing inside the boundary and a light beam passing outside the boundary, and the optical system of an optical pick-up satisfies a condition: