Optical head and drive device for optical recording medium
US6307689A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 17, 2000 |
| Grant date | Oct 23, 2001 |
| Priority date | — |
| Expiry date | Aug 17, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/13727
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical head (1) having an optical means for focusing a laser beam to irradiate an optical recording medium (51) is equipped with an objective lens (2) focusing a laser beam L, and a solid immersion lens (3) disposed between the objective lens (2) and the optical recording medium (51), the head comprising a holder member (4) for integrally retaining the lenses (2) and (3) and a moving mechanism (5a) for moving the holder member in a direction along an optical axis of the lenses (2) and (3), wherein an electrically conductive material is used on a surface of the optical head facing the optical recording medium (51). The numerical aperture can be made large by the solid immersion lens (3). Moreover, the air gap can be controlled with high precision according to the electrostatic capacity formed between the electrically conductive material and the optical recording medium (51). Furthermore, the moving mechanism (5a) and the signal processing for the focus servo operation can be made simpler.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.