Accused infringer attempts to find inequitable conduct in date within invention disclosure

Takeaway: In an attempt to render a patent unenforceable for inequitable conduct, an accused infringer looked to the Invention Disclosure Form for another patent owned by the patentee. The infringer argued that the patentee should have informed the PTO about the other patent because the Invention Disclosure Form showed that the other invention was publicly disclosed before the patent-in-suit, thus making it prior art. The district court found no inequitable conduct because the Invention Disclosure Form clearly described the disclosure date as an expected date of disclosure, and the infringer presented no evidence that an actual disclosure occurred before the filing of the patent-in-suit. Power Integrations, Inc. v. Fairchild Semiconductor Inter., 578 F.Supp.2d 698 (D.Del. 2008).

Details:
Power Integrations, Inc. v. Fairchild Semiconductor Inter., 578 F.Supp.2d 698 (D.Del. 2008)

Power Integrations sued Fairchild for patent infringement. A jury found several claims valid and willfully infringed. A bench trial was held on the issue of inequitable conduct for several of the patents-in-suit. 

With respect to one of the patents-in-suit, the '876 patent, Fairchild argued that Power Integrations failed to disclose to the PTO another Power Integrations patent by the same inventors, the '851 patent. Fairchild asserted that the '851 invention was publicly disclosed before the filing date of the '876 patent-in-suit, thus making it prior art under § 102(a) "known by others"

As evidence of a public disclosure date for the '851 invention, Fairchild pointed to a March 1998 date listed in the patentee's Invention Disclosure Form. Power Integrations countered this March 1998 date was merely an expected public disclosure date, and that public disclosure of the '851 invention did not actually occur until February 1999, after the application for the '876 patent-in-suit was filed.

The court found that March 1998 date relied on by Fairchild was clearly marked on the Invention Disclosure Form as "Expected Date of First Public Disclosure (Ex. Article, Customer Presentation, etc.)". The inventor signing the form testified that the date in question "is an expected date that the inventor or inventors enter as an earliest possible date that would be disclosed, just to give an indication to the attorney on the urgency of the patent ... It doesn't necessarily mean that it was disclosed at that date." The court found no evidence of an actual public disclosure of the '851 invention before the filing date of the '876 patent-in-suit, and thus granted the defendant's motion for Judgment of No Equitable Conduct for the '876 patent-in-suit.

The infringer raised another argument for why the '851 invention should have been considered prior art. The infringer argued that the the Invention Disclosure Form of the '876 patent-in-suit included Fig. 1 of the '851 patent in, and that the Form also described that figure as "prior art." This same figure was included in the patent application for the '876 patent-in-suit -- but was not labeled as "prior art." This inclusion, said the infringer, was an attempt to deceive the PTO, rather than acknowledging the '851 as prior art to the '876 patent-in-suit. The opinion contained no discussion of this issue.


My two cents: The case isn't interesting for it's outcome: the court reached the right result. But as with many other cases, I find the arguments raised by the parties to be of interest. Here, the infringer tried to make something of the dates on the Invention Disclosure Form. It was critical here that the Form clearly indicated Expected Date. I should think that would be enough, such that the inventor's testimony as to the meaning of "Expected Date" was just icing on the cake. But I wonder if the outcome could have been different if the label used on the form said something other than "Expected".

And what about the figure from the '851 patent showing up with the description "prior art" in the the Invention Disclosure Form of the '876 patent-in-suit? The court didn't comment on this. I say this should not be considered an admission of prior art, because "prior art" is a legal term and inventors throw it around without appreciating the significance of the term.

On the other hand, what if an inhouse patent attorney signed the Form too? The inhouse attorney knows the term has significance. So does that extra fact turn it into an admission?