Method for forming video discs
CA 1191597 A · Owner: Discovision Associates · Inventors: Wilkinson, Richard L.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A method for forming a stamper for use in molding video disc replicas in which a disc-shaped master recording is formed which includes a glass substrate and a thin photoresist recording layer. An information signal is recorded in the recording layer in a sequence of spaced pits arranged in a plurality of substantially circular and concentric recording tracks. A first thin, uniform, metallic film is deposited on the master recording. A second thin, uniform metallic film, is electroplated on the first film so that the first and second films together form an integral, metallic layer. The metallic layer is separated from the underlying master and the residual photoresist is removed from the …
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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 August 6, 1985. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended August 6, 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
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.