Objective lens, optical pickup device having the same, and recording and/or reproducing apparatus for optical recording medium, equipped with the optical pickup device
US8064319B2 · kind B2 · utility
0Cited by
5References
8Claims
0Family size
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Key dates
| Filing date | Nov 18, 2008 |
| Grant date | Nov 22, 2011 |
| Priority date | — |
| Expiry date | Jul 6, 2029 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/1374
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An objective lens consists of a single lens element, and has a light source side surface formed into a convex surface having a large curvature and an optical recording medium side surface has a small curvature. The both surfaces are aspheric surfaces. Also, the objective lens satisfies the following expressions (1) to (3):0.7<NA<0.98 (1)0.70<d/f<1.40 (2)0.48<X<0.55 (3).where NA denotes a numerical aperture of the objective lens on an optical recording medium side,
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.