Near field type optical disk recording reproducing apparatus, optical information recording medium recording reproducing apparatus, pickup apparatus, objective lens
US6349083B1 · kind B1 · utility
8Cited by
7References
25Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jul 12, 1999 |
| Grant date | Feb 19, 2002 |
| Priority date | — |
| Expiry date | Jul 12, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/13922
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In a near field type optical disk recording and/or reproducing apparatus, provided with a light source; an objective single lens to converse light from the light source to a focusing point; an optical disk; and a rotating device to rotate the optical disk; the objective lens has a first surface at the light source side and a second surface at the focusing point side, and the first surface is a curved surface on which a diffraction surface is provided.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.