Superresolution optical pickup apparatus
US6025866A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 22, 1998 |
| Grant date | Feb 15, 2000 |
| Priority date | — |
| Expiry date | Apr 22, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B11/10543
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical pickup apparatus including a polarization plane rotary unit arranged between a semiconductor laser and an objective lens, and a polarizing film arranged between the polarization plane rotary unit and the objective lens. The polarization plane rotary unit includes liquid crystal, two glass plates sandwiching the liquid crystal, and transparent electrodes patterned to a predetermined configuration on an inner face of these glass planes. The polarization plane rotary unit permits passage of the laser beam without rotating the plane of polarization of the entire laser beam at the time of recording, and permits passage of the laser beam with the plane of polarization of the center portion of the laser beam rotated and the plane of polarization of the remaining outer portion of the laser beam not rotated at the time of reproduction. Only the outer portion of the laser beam is focused on a magneto-optical disk in a reproduction mode, so that a main beam of a small spot is formed by mutual interference. Since the plane of polarization of the laser beam directed on the magneto-optical disk is not rotated, the Kerr angle of rotation can be detected at high accuracy. As a result, t…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.