Automatic optical focussing system
CA 1081511 A · Owner: N.V. Philips Gloeilampenfabrieken · Inventors: Van Rosmalen, Gerard E.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An automatic optical focussing system suitable for a video disc player comprises an optical focussing device with an objective which is moved to and fro at high frequency in the direction of its optical axis by electrodynamic drive means. The resultant high frequency component thus superimposed on the signal which has been modulated by the information track of the video disc is employed for automatic control of the position of the objective. For the sake of 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 relative thereto and together …
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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Granted July 15, 1980. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended July 15, 1997.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.