Magneto-optical head capable of separating beams for reading recorded information and servo information by use of one optical element
US4951274A · kind A · utility
31Cited by
12References
14Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jan 25, 1988 |
| Grant date | Aug 21, 1990 |
| Priority date | — |
| Expiry date | Jan 25, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/1356
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A magneto-optical head for reading information from a recording medium, the head having a laser-based optical system that comprises two light paths, a first path from the source to and continuing through or reflecting from medium and a second path in a different direction which directs light from the medium to a detector. The second path includes a dual prism multiplying element (Wollaston prism) for dividing the reflected beam into three distinctly oriented beams, and a multi division photodetector for detecting a servo signal by the astigmatism method and an information signal by a differential polarization method.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.