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Expired Canadian patentCanada

Method of forming a variable width channel

CA 1269748 C · Owner: Rca Corporation · Inventors: Ladany, Ivan

CIPO record

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Abstract From the Canadian patent

A method of forming a variable width channel in a body comprises the steps of forming a surface grating having a photoresist layer thereon. The photoresist layer has a plurality of depressions and a planar photomask is then positioned over the photoresist layer. The photoresist layer is subsequently exposed and developed and due to the divergence of light into the depressions covered by the photomask, forms a variable width opening. A portion of the body exposed in the opening is removed to form a channel with a sidewall having a surface contour corresponding to an edge of the opening.

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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 29, 1990. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended May 29, 2007.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledJune 5, 1986
GrantedMay 29, 1990
Term endedMay 29, 2007
Patent numberCA 1269748 C
Classification (IPC)G03C5/00 +2 more

Timeline

Timeline From CIPO dates

1987199019931996199920022005Application filedJune 5, 1986Patent grantedMay 29, 1990Term endedMay 29, 2007

Sources & verification

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