Optical scanning system for focussing a compact-disk player
US4888476A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 20, 1988 |
| Grant date | Dec 19, 1989 |
| Priority date | — |
| Expiry date | Jun 20, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/094
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An arrangement for adjusting a radiation detector in a scanning system that scans a surface, in which the surface reflects rays emitted by a radiation source. The reflected rays are focused onto a radiation detector by at least one focusing element. The radiation detector has at least two individual detectors. A summation signal and at least one difference signal is constructed from output signals of the detectors. The radiation detector is adjusted perpendicular to the optical axis of the system by oscillating selectively one of the source of radiation, the focusing element, or the surface so that a focal point arrives in front of the radiation detector when the oscillating focusing element, oscillating source of radiation, or oscillating surface is displaced by a maximum in one direction. The focal point, on the other hand, arrives behind the radiation detector when the focusing element, source of radiation, or surface is displaced by a maximum in another direction. The value of the difference signal is stored when the summation signal is at a maximum.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.