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Expired Canadian patentCanada

Segmented image holographic disks

CA 2128575 C · Owner: Dai Nippon Printing Co. Ltd. · Inventors: Wreede, John E.

CIPO record

Overview

Drawings and full text

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

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Abstract From the Canadian patent

A hologram structure including a plurality of holograms having substantially identical reconstruction characteristics disposed on a substrate for rotation about a rotation axis and containing segments of a composite image. The holograms are angularly offset relative to each other about a rotation axis such that the composite image is visible over at least one narrow solid angular region pursuant to rotation of the holograms about the rotation axis and illumination of the holograms with a reconstruction beam.

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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 July 21, 1994 and granted November 10, 1998. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended July 21, 2014.
  • A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by July 21, 2016.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledJuly 21, 1994
GrantedNovember 10, 1998
Term endedJuly 21, 2014
Patent numberCA 2128575 C
Classification (IPC)G03H1/28 +2 more

Timeline

Timeline From CIPO dates

1995199719992001200320052007200920112013Application filedJuly 21, 1994Patent grantedNov 10, 1998Term endedJuly 21, 2014

Sources & verification

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