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Expired Canadian patentCanada

Optical information recording medium

CA 1320573 C · Owner: Arai, Yuji · Inventors: Arai, Yuji; Hamada, Emiko; Shin, Yuaki

CIPO record

Overview

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Its claims, description and drawings are in the Canadian Patents Database.

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Abstract From the Canadian patent

An optical information recording medium of the type wherein recorded data are reproduced by scanning them with a laser beam, which comprises a ROM region where optically readable pits are already formed and an information recordable region where optically readable pits can be formed by irradiation with a writing laser beam, wherein the information recordable region comprises a light transmitting substrate having a deformable surface, a light absorptive layer overlaying the deformable surface, to absorb the writing laser beam, and a light reflective layer overlaying the light absorptive layer, said deformable surface being deformable by energy generated upon absorption of the writing laser …

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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 July 20, 1993. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended July 20, 2010.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledMay 11, 1989
GrantedJuly 20, 1993
Term endedJuly 20, 2010
Patent numberCA 1320573 C
Classification (IPC)G11B7/00

Timeline

Timeline From CIPO dates

1990199319961999200220052008Application filedMay 11, 1989Patent grantedJuly 20, 1993Term endedJuly 20, 2010

Sources & verification

Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.