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Documents in Publicly-Available Patent File History are Prior Art Against US Patents

July 1, 2006

Two US patents were recently invalidated on the basis of obviousness in view of a Canadian patent file history that included two figures that were cancelled during prosecution. The Canadian patent was an older patent that was never published as an application. It was confidential until it issued as a patent. The US Court of Appeals found that the Canadian application cancelled figures were a prior art “printed publication” because the Canadian file history was available to the public following patent issuance, which was more than a year before the US patent filing dates. The Canadian application could be located in a reasonably diligent search by a person of ordinary skill in the art. The cancelled application figures were found to be prior art even though there was no evidence that they were ever disseminated beyond the patent application file history.

Bruckelmyer v. Ground Heaters (2006), 455 F.3d 1374 (Federal Circuit).

Edited by Noel Courage. Please send feedback and suggestions to Noel at

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Noel Courage Noel Courage
B.Sc. (Biochem.), LL.B.
416.957.1655  email Noel Courage