Method of producing iron oxide photo masks and iron oxide masks obtained in accordance with this method
CA 1110507 A · Owner: N.V. Philips Gloeilampenfabrieken · Inventors: Popma, Theo J.A.; Kamminga-Schrijnemakers, Maria G.J.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Method of producing photomasks of X-ray amorphous iron oxide (Fe203) by spraying a transparent substrate at a temperature between 180 and 250°C with a solution of an hydrolysable iron salt in a polar organic solution or, in accordance with a variant of this method, at a temperature between 180 and 750°C with a solution of a hydrolysable iron salt which also contains a salt of a metal having a greater ion diameter. If temperatures above approximately 230°C are used, the solvent may in the latter case also consist of water only. -10-
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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 October 13, 1981. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended October 13, 1998.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
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Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.