Automatic optical focussing system
US4032776A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 23, 1976 |
| Grant date | Jun 28, 1977 |
| Priority date | — |
| Expiry date | Feb 23, 1996 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/0917
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An automatic optical focussing system, suitable for a video disc player, comprising an optical focussing device with an objective which is moved to and fro at high frequency in the direction of its optical axis by electro-dynamic drive means, the superimposed high frequency component of the signal which has been modulated by the information tracks on the video disc being employed for automatic control of the position of the objective. In view of a low power consumption the objective is connected to an oscillation-compensation element by means of at least one resilient element, for example a circular plate, which compensation element is axially movable or relative thereto, and which together with the objective and the resilient element constitutes a mechanical resonant system. On the resonant system a piezo-electric acceleration transducer may be mounted with the aid of which the mechanical resonant system can be included in a self-oscillating loop.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.