This case is back in this court on remand from the Supreme Court of the United States. See Warner-Jenkinson Co. v. Hilton Davis Chem. Co., -- U.S. --, 117 S. Ct. 1040 (1997). In Warner-Jenkinson, the Court reversed the judgment of this court ...
Because of this presumption, we expect that the PTO and applicants will henceforth usually include in the prosecution history express statements of their reasons for requiring or making claim changes or interpretive assertions. Express recitations may not exist, however, in applications prosecuted prior to the Supreme Court’s decision. See Warner-Jenkinson, 117 S. Ct. at 1055 (Ginsburg, J., concurring) (“Years after the fact, the patentee may find it difficult to establish an evidentiary basis that would overcome the new presumption.”). Thus, we conclude that where the prosecution history is silent or unclear the district court should give a patentee the opportunity to establish the reason, if any, for a claim change. See id. (urging the Federal Circuit to “bear in mind the prior absence of clear rules of the game”).
IPBiz notes that of the issue of "equivalent: yes or no," the patentee won, with the CAFC writing:
We have reconsidered the pH equivalence issue in light of the Supreme Court’s guidance and hold that there is substantial record evidence to support the jury’s verdict of equivalence. The ‘746 patent claim recites a pH range “from approximately 6.0 to 9.0.” Warner-Jenkinson performed the process using a pH of 5.0.
Separately, IPBiz observes that the text in the amended claim was used because that was the text in the specification for which there was written support. The lower limit of 6 was not needed for prior art, but the upper limit of 9 was lower than that needed to overcome prior art. NEITHER 6 NOR 9 was optimal for the patentee but that it was the patentee had support for.
Of the text --There is no law that says if one discloses a range, then both ends of the range must be incorporated into any related claim. Furthermore, even if some court ultimately did decide this, at the time of prosecution one should not assume that outcome.-- how about 35 USC 112 P1, which is probably what the patent prosecutor ran into when he/she had to amend? There has to be written description support for a claim amendment, and a range 6-9 is not the same thing as less than 9. The patentee was forced into the 6-9 range by the examiner, long before any court looked at this. This is why experienced prosecutors include ranges which express alternative embodiments.
And this of course doesn't answer the real question: if 6-9 was forced because of 112, and not because of 102/103, was that related sufficiently to patentability to invoke estoppel? That question was never answered in Hilton Davis.