Polarizer, including thin polarizing film, optical element with polarizer, optical head with polarizer and methods and apparatus for forming same
US5825022A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 30, 1996 |
| Grant date | Oct 20, 1998 |
| Priority date | — |
| Expiry date | Apr 30, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/13727
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A plurality of inclined planes (1419) are formed in the same substrate (1406) and a polarizing optical thin film is provided on these inclined planes. These inclined planes are filled with a transparent material so as to form a small sized and complexed polarizer. This polarizer is excellent in transmission ratio and in extinction ratio. With this polarizer, it is possible to detect a magneto-optical signal with a high signal-to-noise ratio. This polarizer is used as a cover of a package (1408) of an optical head in which a light receiving device (1410, 1411) and a light emitting device (1409) are contained in the form of a single piece. There is also provided an optical element capable of adjusting optical paths so that the optical length of a returning optical beam may be different from the optical length of a forward optical beam. With this optical element, it becomes possible to delete the initial offset in a focusing error signal, and thus adjustment process becomes unnecessary. With these arrangements, it is possible to achieve the size reduction, simplification, and improvement of performance associated with an optical head for use in a magneto-optical recording/reproducing …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.