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Expired Canadian patentCanada

Pure green light emitting diodes and method of manufacturing the same

CA 1237514 A · Owner: Matsushita Electric Industrial Co. Ltd. · Inventors: Matsuda, Toshio; Iwasa, Hitoo; Kawabata, Toshiharu

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Abstract From the Canadian patent

Pure-green light emitting diodes comprise an n-type GaP layer formed on an n-type GaP substrate and a p-type GaP layer formed by using a liquid phase epitaxial method, the average donor concentration of the p-type GaP layer being less than or equal to 5 x 1016 cm-3. Liquid phase crystal growth of the above p-type GaP layer is realized by applying a method of keeping the melt used for the liquid phase crystal growth of the n-type GaP layer at a constant temperature and the ambient atmosphere at a reduced pressure for a prescribed period of time thereby to volatilize donor impurities from the melt and to compensate the donor impurities. Pure-green light emitting diodes easily distinguishable …

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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 May 31, 1988. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended May 31, 2005.
  • 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 26, 1983
GrantedMay 31, 1988
Term endedMay 31, 2005
Patent numberCA 1237514 A
Classification (IPC)H01L33/30 +2 more

Timeline

Timeline From CIPO dates

19841987199019931996199920022005Application filedJuly 26, 1983Patent grantedMay 31, 1988Term endedMay 31, 2005

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