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Expired Canadian patentCanada

Optical electric-field measuring apparatus

CA 1205859 A · Owner: Hitachi Cable, Ltd. · Inventors: Nagatsuma, Kazuyuki; Katsuyama, Toshio; Matsumura, Hiroyoshi

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 electric-field measuring apparatus utilizing electrooptic effect for measuring the intensity of electric DC field includes a material exhibiting both electrooptic effect and photoelectric effect or both a material exhibiting the electrooptic effect and a material exhibiting the photoelectric effect which material or materials are irradiated with a continuous light ray of a wavelength capable of inducing the electrooptic effect and an intermittently interrupted light ray of a wavelength capable of inducing the photoelectric effect.

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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.
FiledJuly 13, 1983
GrantedJune 10, 1986
Term endedJune 10, 2003
Patent numberCA 1205859 A
Classification (IPC)G01R29/12 +2 more

Timeline

Timeline From CIPO dates

1984198619881990199219941996199820002002Application filedJuly 13, 1983Patent grantedJune 10, 1986Term endedJune 10, 2003

Sources & verification

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