Optical reader for information discs equipped with means for automatic access to the information
US4138663A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 27, 1978 |
| Grant date | Feb 6, 1979 |
| Priority date | — |
| Expiry date | Jun 27, 1998 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05B2219/37275
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The optical reader, for information discs of which the items of information are locatable by addresses previously recorded on each of the grooves forming the track, comprises a device for counting the number of grooves traversed during search phases which simultaneously uses the envelope of the reading signal and the signal representing the radial error in the position of the head relative to the nearest track, for algebraically counting the number of tracks traversed. After comparison with the number of grooves to be traversed, the counting device controls the deceleration of the radial advance when the spot is at a predetermined distance from the groove to be reached and also its total stoppage and the closure of the radial servocontrol loop when the groove is reached.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.