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Expired Canadian patentCanada

Radiation sensitive compositions

CA 1253728 A · Owner: Vickers Plc · Inventors: Folkard, Christopher W.; Millross, Christopher R.

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Abstract From the Canadian patent

Radiation sensitive compositions are image-wise exposed and developed to form an image which is then heated to improve its strength as a lithographic printing image or etch resist. The heating is carried out in the presence of a heat sensitive dye which undergoes a colour change at a temperature of at least 180°C so as to obtain an indication of whether or not the heating has been adequate. The dye may be an integral component of the composition or it may be applied to the image after, development, in combination with a substance capable of forming a shield against contaminating residues produced during the heating step.

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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 9, 1989. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended May 9, 2006.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledMay 30, 1984
GrantedMay 9, 1989
Term endedMay 9, 2006
Patent numberCA 1253728 A
Classification (IPC)G03C1/52 +2 more

Timeline

Timeline From CIPO dates

19851988199119941997200020032006Application filedMay 30, 1984Patent grantedMay 9, 1989Term endedMay 9, 2006

Sources & verification

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