Optimal polarization for the optical readout of high density video recording
US4310910A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 25, 1979 |
| Grant date | Jan 12, 1982 |
| Priority date | — |
| Expiry date | Apr 25, 1999 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/1365
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Recovery from a record of data recorded in an elongated information track, comprising depressed areas of various lengths alternating with non-depressed areas, is effected by an optical playback system. The playback system employs apparatus for focusing a laser source as a light spot on the information track. A light detector, responsive to light diffracted by the information track as relative motion is established between the light spot and the information track, is used in the playback apparatus to translate the depressions in the information track into frequency-modulated electrical signals. When the light spot size or depression spacing becomes comparable to the wavelength of the laser source, the signal strength at the detector output becomes dependent upon the polarization of the light spot incident on the information track. In the playback system, apparatus is provided for orienting the polarization of the light spot on the information track to enhance the signal strength of the detector output.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.