NATICK, Mass., Feb. 1 -- Machine vision system supplier Cognex Corp. said the US Court of Appeals for the Federal Circuit has ruled in Cognex's favor in an important appeal related to Cognex's lawsuit against the Lemelson Medical, Education & Research Foundation, Limited Partnership. The appeal ruling, issued on Jan. 24, gives Cognex the right to raise the doctrine of patent prosecution laches as one of its defenses to the Lemelson Partnership's infringement claims. The doctrine of prosecution laches bars a patentee from enforcing a patent claim when there was an unreasonable delay in seeking the claim from the Patent Office. Cognex is contending that Lemelson's unreasonable delays in the prosecution of certain machine vision patent claims -- in many cases more than 30 years after his original 1954 and 1956 applications -- constitute laches. If Cognex is successful in arguing the laches defense when its lawsuit against the Lemelson Partnership goes to trial, the court could hold the vast majority of the Lemelson patent claims unenforceable. The case is expected to go to trial in August 2002. Cognex filed suit against the Lemelson Partnership in September 1998, seeking a declaration that various patents that claim to cover machine vision, currently assigned to the Partnership by the late Jerome H. Lemelson, are invalid, unenforceable and not infringed by either Cognex or by any users of Cognex products.