Apparatus for writing and/or reading information in/from a disc shaped record carrier
CA 1308192 C · Owner: Mcgee, Philip J.L. · Inventors: Mcgee, Philip J.L.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Apparatus for writing and/or reading information in/from a disc-shaped record carrier. The apparatus comprises a light source (7) for producing a light beam, an objective system (8) for focussing the light beam, first detection means (13 48), for generating a first control signal (S1) which has a value which varies substantially proportionally to the radial distance of the light spot relative to the track over a control range of p/4, p being the track pitch and radial positioning means (47) for. controlling the radial position of the light spot (P) on the track (Fig. 1) under the influence of said first control signal. The detection means (13 48) comprise correction means (48), for …
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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 September 29, 1992. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended September 29, 2009.
- 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.