Recapture Invalidity Avoided by Amendments Not Distinguishing Prior Art
ConAgra contended that during the prosecution of the original patent, Kim surrendered (1) a non-phosphate potassium bromate replacer composition, and (2) a potassium bromate replacer composition with a food acid range broader than 0.02-0.15 parts per 100 parts flour.
Under U.S. law, the challenger of the reissued patent, here ConAgra, must establish surrender of recaptured subject matter by clear and convincing evidence. A patentee can surrender subject matter either through arguments or amendments made during the prosecution of the original patent. Whether surrender of recaptured subject matter has occurred is a question of law, which we review de novo.
According to Circuit Judge Dyk,
In determining whether "surrender" of subject matter has
occurred, the proper inquiry is whether an objective observer viewing the prosecution history would conclude that the purpose of the patentee’s amendment or argument was to overcome prior art and secure the patent. This is because the recapture rule is aimed at ensuring that the public can rely on a patentee’s admission during prosecution of an original patent. It is precisely because the patentee amended his claims to overcome prior art that a member of the public is entitled to occupy the space abandoned by the patent applicant.
. . . [T]he reissue statute cannot be construed in such a way that competitors, properly relying on prosecution history, become patent infringers when they do so." Mentor Corp., 998 F.2d at 996; see also Vectra Fitness, Inc. v. TNWK Corp.,162 F.3d 1379, 1384 (Fed. Cir. 1998) ("[T]he ‘recapture rule’ prevents a patentee from regaining through reissue subject matter surrendered during prosecution, thus ensuring the ability of the public to rely on a patent's public record.") (emphasis added). [Footnote here: "Deliberately canceling or amending a claim in an effort to overcome a reference strongly suggests that the applicant admits that the scope of the claim before the cancellation or amendment is unpatentable, but it is not dispositive because other evidence in the prosecution history may indicate the contrary." In re Clement, 131 F.3d 1464, 1469 (Fed. Cir. 1997). ] Thus, if the objective public observer can discern a surrender of subject matter during the prosecution of an original patent in order to overcome prior art and obtain the patent, then the recapture rule should prevent the reissuing of that patent to claim the surrendered subject matter.
With this in mind, we turn to ConAgra’s allegations of surrender. . . .
. . . Kim overcame the obviousness rejection by changing the transition phrase from "comprising" to "consisting essentially of" and by changing her method claims to composition claims. While the phosphate limitation was added at the same time, the prosecution history does not indicate that Kim added that limitation in particular in order to overcome the obviousness rejection. Significantly, the examiner had previously rejected claims of the original application that included phosphate and noted that the phosphate salt limitation there was not "patentably significant." Thus, the prosecution history refutes the argument that phosphate was added by Kim to overcome a rejection.
. . . As the district court explained, "the range for the food acids used in the pertinent prior art (Tanaka) had been .0005 to .006. Plaintiff’s lower end choice of .015 [in the reissue application] or 0.02 [in the original application] are both a significant difference from .006. It can not be inferred that plaintiff’s choice of .020 instead of .015 was because
plaintiff was surrendering the difference between the two out of fear .015 would be found to be obvious while .020 would not." Further, "[t]he Patent Examiner did not indicate that [the original application’s] range [of 0.03-0.2] was obvious in light of the prior art. Instead, the Patent Examiner indicated that the use of food acid and ascorbic acid in general was disclosed by the prior art and that the particular range . . . was indefinite in that it was unclear if it was measured solely in ratio to flour."
We agree with the district court.