Optical data storage system with multiple write-once phase-change recording layers
CA 2220879 C · Owner: Tang, Wade Wai-Chung · Inventors: Rubin, Kurt Allan; Rosen, Hal Jervis; Tang, Wade Wai-Chung
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An optical disk drive (10) uses an optical disk (12) with spatially separated multiple phase-change WORM recording layers (51 66). The optical disk has a , light transmissive substrate onto which the laser light is incident. The substrate supports at least two spatially separated multi-film recording stacks (90, 92), each stack including an active recording layer of phasechange WORM material. The disk is either an air-gap (78) structure wherein each recording stack is supported on a separate substrate (50 56) and the , substrates (50, 56) are separated by an air-gap (78) or a solid structure , wherein a solid light transmissive spacer layer (22) separates the recording stacks (90, 92). …
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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
- Filed March 8, 1996 and granted April 2, 2002. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended March 8, 2016.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 8, 2018.
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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.