Honeywell Ruling (RCTA)
In petitioning a rehearing, counsel for Honeywell addressed our two concerns, arguing 1) that the Hamilton Sundstrand device was equivalent to their patented design and method and 2) to rebut the presumption of prosecution history estoppel. We vacate the latter issue and remand the former issue.
Honeywell cited this Court’s logic in Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., 535 U.S. 722, 733 (2002) and in Warner-Jenkinson Company v. Hilton Davis Chemical Co., 520 US 17 (1997). We agree that the rationale behind patent claims should be considered when determining whether the presumption of prosecution history estoppel might be rebutted. However, it is more important that patents serve their dual functions of promoting the progress of science and the useful arts and of informing the public of the scope of their unusual monopolies.
Therefore, following the holding of Festo, what the original claims contained when compared to what the revised claims contained will be the most important factors in determining whether the alleged equivalents are barred by estoppel. For example, an original claim might contain elements A, B, and C. If it is rejected by the patent examiner in light of the prior art and then later allowed to issue with the claim rewritten to include elements A, B, C, and D, then the patent holder clearly relinquishes all claim to A, B, and C together without D. Amending claims to avoid the prior art should always bar future expansion into that area, even by equivalents.
Honeywell claimed that its revision of its dependent claims into independent claims did not add the element of the IGVs. Instead, what occurred was merely procedural: the revision of one, higher-level claim resulted in the lower claims being rewritten in independent form; this occurred as if in a cascade, with no bearing on patentability. In this “cascade” kind of case, where revisions do not add limitations but merely comply with procedural guidelines, the estoppel presumption may be rebutted in light of the other facts of the case.
Furthermore, even if estoppel is presumed, Honeywell argues that it may be rebutted because the equivalent would not have been foreseeable at the time the patent was filed. This argument follows the precedent of the lower court and has merit. Honeywell also argued that Hamilton Sundstrand infringed because their device contained all the elements of the Honeywell patent, adding only the DELPQP calculation parameter to distinguish between high and low flow.
Johnston v. IVAC Corp., 885 F .2d 1574 (1989) was a case of non-equivalence: the two devices had the same goal but used very different means to achieve it. This is method equivalence. Here, the two devices use the same means to achieve different immediate goals. The Sundstrand device is unique in its measuring of the IGVs’ positions to determine high and low flow. However, both have similar ultimate goals.
In response, Hamilton Sundstrand did not address the equivalency issue but instead argued that Honeywell’s patent was foreseeable and that, consequently, Hamilton Sundstrand could not be held liable for damages. The burden is upon Honeywell to craft its claims carefully; however, the ordinary meaning of language should be relied upon when determining equivalents or foreseeability, especially ten years after an invention. Hamilton Sundstrand contended that the equivalence issue was foreseeable a long time prior to Honeywell’s patent in light of the prior art of the 1970s: the L1011’s use of static pressure differentials. Both sides conceded that there was no literal infringement, and Hamilton Sundstrand argued that the doctrine of equivalents could not be used because of foreseeability. That is, Honeywell should have covered Hamilton Sundstrand’s use in their claim.
We find that the equivalent was not foreseeable in light of the prior art. Not only did Honeywell’s invention address a long-standing problem in the field, the applications of the 1970s were significantly different from those of Honeywell. For the above reasons, we vacate the holding insofar as it relied upon the presumption of prosecution history estoppel and remand to the lower court for evaluation of the infringement claim and the alleged equivalency of the Hamilton Sundstrand device with that of the patented Honeywell device.
Finally, the logic of the court below regarding tangentiality does not rely upon facts internal to the patent or to the patent prosecution process; rather, tangentiality is dependent upon what is contained within the future alleged infringement. The dissenting opinion of Judge Newman is illustrative: “[The tangentiality] criterion relates to why an amendment was made; it does not become irrebuttable simply when the accused equivalent concerns the same element that was added by amendment.” Each patent must be evaluated on its facts and circumstances at the time of its filing. The prosecution file wrapper is thus important both for the Courts and the public in determining patent scope. While the amendment would not be material to the case unless it concerns the same element as the accused equivalent, this simple association does not make rebuttal of estoppel presumption impossible.