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Expired Canadian patentCanada

Light valve containing suspension of perhalide of alkaloid acid salts or metal halide

CA 1136401 A · Owner: Research Frontiers Incorporated · Inventors: Saxe, Robert L.

CIPO record

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Abstract From the Canadian patent

R.L.Saxe - 5, ABSTRACT OF THE DISCLOSURE A light valve comprises a cell containing a suspension of light-polarizing particles in a liquid suspending medium, the light polarizing particles being particles of a light-polarizing perhalide of a polycarboxylic acid salt of an alkaloid.

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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 November 30, 1982. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended November 30, 1999.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledOctober 24, 1979
GrantedNovember 30, 1982
Term endedNovember 30, 1999
Patent numberCA 1136401 A
Classification (IPC)G02F1/01 +1 more

Timeline

Timeline From CIPO dates

1980198219841986198819901992199419961998Application filedOct 24, 1979Patent grantedNov 30, 1982Term endedNov 30, 1999

Sources & verification

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