Magneto-optical reproducing head of a high light utilization rate
US4729122A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 17, 1985 |
| Grant date | Mar 1, 1988 |
| Priority date | — |
| Expiry date | Oct 17, 2005 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B11/10576
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In a magneto-optical reproducing head including first and second beam splitters (21, 22) and a Faraday effect member (25) between the splitters to suppress return to a laser beam source (11) of a reversed laser beam reversedly sent from a magneto-optical recording medium (12) on which a forward laser beam is incident, the second beam splitter is made to have a transmissivity of at least 0.5 for a p-polarized component. For an s-polarized component, the second beam splitter has a reflectivity which is substantially equal to unity as usual. In order to produce a servo control signal, a signal producing circuit (17) is made to receive an s-polarized component which is substantially totally reflected in the first beam splitter and into which the Faraday effect member converts the p-polarized component having reversedly passed through the second beam splitter. The transmissivity of the second beam splitter should preferably be at least 0.75 and not greater than 0.8. An optically active member (35) is preferably interposed between the Faraday effect member and either the first or the second beam splitter. The head is readily used in recording information on the recording medium and/or in…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.