Optical recording medium
CA 1250176 A · Owner: International Business Machines Corporation · Inventors: Wieder, Harold; Onton, Aare; Lee, Michael H.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Abstract of the Disclosure An optical recording medium comprising adjacent thin layers of two different materials, which upon marking, with an energy beam, form a marked area comprising an alloy or mixture of the two materials. The optical properties of the marked area has contrast sufficiently different from the optical properties of the unmarked area so that the marked area can be reliably sensed. One of the first of the thin layers comprises a metal and the other of the thin layers comprises a metal or a semiconductor. The metals are taken from the group comprising Al, Au, Pb and Sn and the semiconductors are chosen from the group comprising Ge and Si.
Read the whole patent
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 February 21, 1989. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended February 21, 2006.
- 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.