Magneto-optic recording and playback system
US5278811A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 7, 1992 |
| Grant date | Jan 11, 1994 |
| Priority date | — |
| Expiry date | Jul 7, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B11/10543
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A magneto-optic reading apparatus includes a laser light source for generating a linearly polarized light beam and a quarter-wave plate which converts the linearly polarized light beam into a circularly polarized light beam. A beam splitter separates the circularly polarized light beam into a first beam which passes therethrough and a second beam which is reflected. An objective lens converges the first beam so as to scan one of the data tracks of a magneto-optic recording element. The information written along the scanned data track causes the polarization of the first beam to be modulated as the first beam is reflected by the recording element toward the first beam splitter. The first beam splitter further separates the first beam into a third beam which passes therethrough and a fourth beam which is reflected. The quarter-wave plate converts the third beam into a linearly polarized light beam which has a polarization that is substantially transverse to the polarization of the light beam from the laser light source. A polarizing beam splitter prevents the third beam from reaching the laser light source. An optical signal detecting system receives the fourth beam from the first be…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.