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Expired Canadian patentCanada

Optical beam switching device and telephone exchange comprising a device of this kind

CA 1205892 A · Owner: Thomson-Csf · Inventors: Ledu, Bertrand; Huignard, Jean-Pierre

CIPO record

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

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Abstract From the Canadian patent

The invention relates to switches enabling -the connection by an optical method of at least one of the circuits of a set of input circuits to at least one circuit of a set of output circuits. It consists in illuminating a photosensitive medium with parallel input beams coming from a set of input circuits. The input beams are then diffracted on strata inscribed on the medium to reach one of the circuits of a set of photoreceptor circuits. The strata are inscribed by interference of two inscribing beams of which the wavelength differs from that of the input beams; the wavelength of these input beams not lying within the range of spectral sensitivity of the photosensitive medium.

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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 June 10, 1986. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended June 10, 2003.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledDecember 15, 1982
GrantedJune 10, 1986
Term endedJune 10, 2003
Patent numberCA 1205892 A
Classification (IPC)H04Q3/52

Timeline

Timeline From CIPO dates

1983198619891992199519982001Application filedDec 15, 1982Patent grantedJune 10, 1986Term endedJune 10, 2003

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