Objective lens system and optical disk apparatus using the same
US6552858B2 · kind B2 · utility
3Cited by
2References
8Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Nov 29, 2001 |
| Grant date | Apr 22, 2003 |
| Priority date | — |
| Expiry date | Nov 29, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/13727
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An objective lens system includes a first lens and a second lens. The first lens has a first surface for allowing entry of light and a second surface opposite to the first surface. The second lens has a spherical third surface and a flat fourth surface opposite to the third surface. The third surface faces the second surface and has a radius of curvature r0. The second lens has a thickness d0 and a refractive index n0. The thickness n0, the radius of curvature r0 and the refractive index n0 satisfy a relation: d0>r0>n0d0.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.