In December 2005, a jury returned a verdict in favor of Praxair, finding two of its patents valid and infringed. A bench trial regarding inequitable conduct followed the jury trial. This opinion addresses the inequitable conduct issue.
Praxair asserted three references that were not disclosed to the PTO. The Court found only two of those references were sufficiently material to merit further consideration. Of these two remaining references, only one reference was found to have been intentionally withheld from the examiners of the two patents at issue. Interestingly, the court relied on the high materiality of the omitted reference and the “absence of any explanation for the nondisclosure” to infer an intent to deceive. Op. at 12. The Court found significant the facts that 1) Praxair was using the technology in the omitted reference in its own products for several years before filing the patent applications, and 2) one of the inventors built devices that utilized the technology in the omitted reference. Op. at 12, fn 9.
Moral of the story: If you are a patent prosecutor, this is the type of decision that might make you lose sleep. You ask the inventors to turn over any potentially relevant prior art, but do your words go in one ear and out the other? Maybe the take away is for patent attorneys to put their requests to inventors in writing (if you don’t already) – just in case.