Apparatus for recording and reading information tracks in an optical record carrier
CA 1193721 A · Owner: N.V. Philips Gloeilampenfabrieken · Inventors: Opheij, Willem G.; Van Rosmalen, Gerard E.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
24-, ABSTRACT:, "Apparatus for writing and reading information tracks in an optical record carrier". An apparatus is described for writing and reading information tracks in an information surface of a record carrier by means of optical radiation. The apparatus comprises two diode lasers, one of which produces the write beam and the other a read beam. By means of polarisation means the write spot and the read spot formed on the information layer are projected at a very small and stable distance from each other and the beams reflected by the information layer are spatially separated. The separated beams are routed to separate detectors residual cross-, talk between the beams being eliminated …
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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 17, 1985. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended September 17, 2002.
- 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
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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.