Optical head using a reflection grating
US5036504A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 30, 1988 |
| Grant date | Jul 30, 1991 |
| Priority date | — |
| Expiry date | Nov 30, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/1378
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical head includes a reflection type grating lens for dividing specified polarized lights into a reflected light and a diffracted light, a device for detecting a RF signal from the reflected light of the grating lens, and a device for detecting focusing and tracking error signals from the diffracted light of the grating lens. The grating lens consists of a plurality of domains having different optical properties respectively, so that the reflected and diffracted lights are obtained. The optical head further includes a total reflection prism to compensate a phase difference between polarized lights orthogonal to a grating groove of the grating lens and parallel thereto, and a polarizing prism for dividing the reflected light into two polarized lights orthogonal to each other in polarization thereof. Thus, a simple, miniaturized, and inexpensive optical head is obtained.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.