On remand from the Supreme Court: what are the requirements (1) for prosecution history estoppel, and (2) the preservation of meaning for each element in a claim?
“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.” “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. . . . Accordingly, assuming prosecution history estoppel does not preclude such a finding, we reaffirm our prior decision that a pH of 5.0 is equivalent to a pH of ‘approximately 6.0’ in the context of the claimed process.