Objective lens and optical pickup apparatus
US6807139B2 · kind B2 · utility
11Cited by
13References
32Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Apr 8, 2002 |
| Grant date | Oct 19, 2004 |
| Priority date | — |
| Expiry date | Apr 15, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/0006
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An objective lens comprises at least inner and outer optically functional regions arranged in a direction perpendicular to an optical axis and each of the inner and outer optically functional regions has a diffractive structure. The objective lens comprises a light amount reducing structure to reduce an amount of the light flux passing through a region of the objective lens other than the inner optically functional region when recording or reproducing is conducted for CD.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.