Introduction
On remand from the Supreme Court,1 the Court of Appeals for the Federal Circuit recently revisited the issue as to whether prosecution history estoppel barred a patent owner from relying on the doctrine of equivalents in a patent infringement suit. In this highly anticipated decision, Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., Ltd.,2 the court concluded that the doctrine of equivalents might still be available to the patentee and remanded the case to the district court to make the determination. In reaching this conclusion, the Federal Circuit addressed whether any of three mechanisms for rebutting the presumption that prosecution history estoppel applies were available to the plaintiff and determined that one of them – unforeseeability – might be. But along the way, the Court of Appeals took a good deal of the teeth out of the other two mechanisms that the Supreme Court gave, perhaps leaving unforeseeability as the only practical way of rebutting the presumption that a narrowing amendment surrenders all subject matter between the original and the amended claim limitations.
Factual Background
Plaintiff Festo brought suit in 1988 against Shoketsu Kinzoku Kogyo Kabushiki Co., Ltd., and SMC Pneumatics, Inc. (collectively hereafter, "SMC") in the United States District Court for the District of Massachusetts.3 The case involved the alleged infringement of two patents owned by Festo, the "Stoll" and "Carroll" patents, which related to magnetic, rodless cylinders that could be used as part of a mechanism for moving objects along a conveyor system. Both patents were amended during their prosecutions. Of significance here, claim 1 of the Stoll patent was amended to add the limitation of "a cylindrical sleeve made of a magnetizable material."4 SMC's accused device contained an aluminum (a non-magnetizable metal) sleeve. In addition, both the Stoll and Carroll patents contained "sealing ring" limitations which were amended specifically to recite two sealing rings.5 SMC's accused device included a single, two-way sealing ring. SMC argued that Festo's amendments effectively surrendered the aluminum sleeve and single two-way sealing elements of its accused device, thus barring (or estopping) Festo's claims of infringement under the doctrine of equivalents.6 Addressing the issue in the context of summary judgment motions and in consideration of a prior infringement analysis by a special master, the district court held that prosecution history estoppel did not bar the application of the doctrine of equivalents to the claims asserted by Festo. Following that decision, the jury rendered its verdict that SMC infringed the Stoll and Carroll patents.7
SMC then appealed both the jury verdict and the district court's decision on summary judgment. The Federal Circuit initially affirmed the lower court's outcome.8 However, the Supreme Court, in light of its then-recent decision in Warner-Jenkinson v. Hilton Davis Chemical Co.,9 granted certiorari and reversed and remanded the decision back to the Federal Circuit.10 Following this first remand from the Supreme Court, a panel of the Court of Appeals again affirmed the district court's judgment of infringement under the doctrine of equivalents.11 Next though, SMC petitioned the Court of Appeals for re-hearing en banc,12 and the court agreed, seeking to resolve issues relating to the doctrine of equivalents which remained in light of the Supreme Court's Warner-Jenkinson opinion."13
The Federal Circuit's First En Banc Decision
The majority decision, written by Judge Schall, attacked head-on the doctrine of equivalents by explicitly analyzing and answering four questions specifically briefed for the en banc1 hearing (a fifth question was briefed, but the court considered it moot in view of its rulings on the other four questions).
The first question was whether the types of amendments that can create prosecution history estoppel are limited to those made only to overcome prior art objections under 35 U.S.C. §§ 102 and 103. Here, the court held that any amendment that narrows the scope of a claim for reasons related to the statutory requirements for a patent will give rise to prosecution history estoppel with respect to the amended claim element.14
Second, the court examined whether a claim amendment that was not required by or made in response to a rejection by an examiner can create prosecution history estoppel. According to the majority, so-called "voluntary" amendments should be treated the same as any other.15 Therefore, "voluntary" amendments will also invoke prosecution history estoppel if related to the statutory requirements for a patent.
Next, and most significantly, the court looked to the specific instance when a claim amendment would create prosecution history estoppel and addressed the question of what range (if any) of equivalents would be available to the patentee. In answering this question, the court adopted its infamous "absolute bar" rule, holding that in such a case no range of equivalents is available.16
Finally, the court held that, in cases where no explanation is given for the claim amendment in question, the presumption must be that the amendment was made for purposes of patentability.17 Again, therefore, no doctrine of equivalents would be available to the patentee. In applying these rules to the claims of the case, the court reversed the jury's verdict of infringement in light of the estoppel created by amendments in the prosecution history of both the Stoll and Carroll patents.18
This absolute bar approach was viewed as a radical departure from the established approach, which had allowed some room for equivalents by focusing on the specific subject matter surrendered during amendment. The Supreme Court again granted certiorari to review the court's en banc decision.19
At the Supreme Court -- Again
In its decision, the Supreme Court found the absolute bar to be stringent and too much of a concession to certainty and efficiency at the expense of a patentee's legitimate expectations in a property right. The unanimous opinion, authored by Justice Anthony M. Kennedy, addressed two questions. The first was whether an amendment made for reasons other than to overcome a prior art rejection, such as to overcome the § 112 rejection at issue in the case, may give rise to a prosecution history estoppel. As was expected, the Court answered yes, agreeing with the Federal Circuit's rationale regarding patentability.21
The second question – the appropriateness of the absolute bar – was more controversial and its answer was awaited with much greater anticipation. On this issue, the Supreme Court vacated the Federal Circuit's decision and held that while making a narrowing amendment to a claim element creates a presumption that the doctrine of equivalents cannot be applied, this presumption can be rebutted with a showing that the equivalent at issue was not in fact surrendered.21
Regarding this latter issue, the Supreme Court began with a discussion of the rationale for the doctrine of equivalents, describing it in terms of a policy balance between meaningful protection of the inventor's property right and the need for certainty in determining the scope of the patent monopoly. The Court plainly recognized the need for the doctrine, stating that "the nature of language makes it impossible to capture the essence of a thing in a patent application."22 While recognizing that the doctrine renders the scope of a patent less certain, the Court acknowledged "this uncertainty as the price of ensuring appropriate incentives for innovation."23 On the other hand, the Court explained that prosecution history estoppel is necessitated by the need to prevent the patentee from effectively circumventing the role of the Patent and Trademark Office as a gatekeeper; that is, giving up claim scope to achieve issuance of a patent during prosecution and later – under the guise of the doctrine of equivalents – asserting infringement based upon the relinquished subject matter.24
Moreover, the Supreme Court condemned the complete-bar approach as disruptive of long-settled law and the expectations of existing patentees, as well as inconsistent with the purpose of prosecution history estoppel. That is, estoppel presumes that a narrowing amendment is a concession by the patentee that the scope of the patent does not extend as far as the original claim. "It does not follow, however, that the amended claim becomes so perfect in its description that no one could devise an equivalent."25 The Court further noted the fundamental unfairness of an absolute bar rule to inventors who amended their claims under the old regime and had no reason to think that they would be surrendering all equivalents. Thus, it overturned the Court of Appeals in favor of a "flexible bar" approach that allows some scope of equivalents even for claim elements that have been amended.26
The new flexible bar carried with it a presumption that the amendment did in fact surrender the particular equivalent in question. But the presumption may be rebutted by the patentee's showing that "at the time of the amendment one skilled in the art could not reasonably be expected to have drafted a claim that would have literally encompassed the alleged equivalent."27 The Court offered three more specific instances in which this presumption might be overcome: when the equivalent was unforeseeable at the time of the application, when the rationale for the amendment bears no more than a tangential relation to the equivalent or when there is some other reason suggesting that the patentee could not reasonably be expected to have described the equivalent. The Court remanded the case to the Federal Circuit, for determination as to whether the presumption in this case could be rebutted.
The New (and Flexible) Festo
Following this second remand, the en banc Federal Circuit asked the parties (as well as amici) to brief the following specific issues:
1. Whether rebuttal of the presumption of surrender, including issues of foreseeability, tangentialness, or reasonable expectations of those skilled in the art, is a question of law or one of fact; and what role a jury should play in determining whether a patent owner can rebut the presumption.
2. What factors are encompassed by the criteria set forth by the Supreme Court.
A brief from each side and 15 amici curiae briefs were submitted.
At the outset of the majority opinion written by Judge Lourie,28 the court recognized that the Supreme Court had endorsed expressly its earlier holding that a narrowing amendment may invoke prosecution history estoppel.29 Further, although not addressed by the higher court, the Federal Circuit reinstated its holding that a voluntary amendment similarly may give rise to an estoppel.30
Next, the court sought to clarify the Supreme Court's Warner-Jenkinson presumption, in light of Festo's torturous case history. Specifically, the court emphasized that the Warner-Jenkinson case stands for the presumption that a narrowing amendment has been made "for a ‘substantial reason related to patentability' when the record does not reveal the reason for the amendment."31 Although the Supreme Court had rejected any "complete bar" logic, it confirmed that failure to overcome the Warner-Jenkinson presumption triggered the new Festo presumption of surrender.32
Thus, Warner-Jenkinson and Festo work in tandem in any prosecution history estoppel analysis as follows. First, a court must determine whether an amendment narrowed the scope of a patent claim. If the amendment did not narrow a claim, then prosecution history estoppel was inapplicable. If it was narrowing, the second question is whether the basis for the amendment was "a substantial one relating to patentability."33 Here, Warner-Jenkinson operates to presume the amendment was for a substantial reason relating to patentability.34 Thus, if the prosecution history is silent as to the amendment, the presumption is invoked. To rebut this presumption, a patentee is limited to the evidence in the prosecution history record, or file wrapper, only.35 No extrinsic evidence is permitted for this portion of the analysis.
Next, if a court determines that an amendment was made for a substantial reason related to patentability – either based on the Warner-Jenkinson presumption or from evidence in the file wrapper – then the estoppel inquiry examines the scope of the subject matter surrendered.36 At that point, the new Festo presumption arises, namely, that the patentee surrendered all equivalents between the original and amended claim limitations. If the patentee is unable to rebut this presumption, then the patentee is barred from relying on that range of equivalents surrendered by the amendment.37 On the other hand, if the patentee successfully rebuts the Festo presumption, then prosecution history estoppel is inapplicable and equivalence is reached on the merits.38
Rebutting the Festo Presumption
In answer to the first question regarding the role of the judge and jury in an estoppel inquiry, the Federal Circuit held that this was a question of law for the court to decide, not the jury.39 The court reasoned that the prosecution history is itself a legal limitation to the doctrine of equivalents and as such, is the exclusive province of the court. Further, the court went on to discuss the three ways in which the presumption could be rebutted: by a showing of unforeseeability of the alleged equivalent, by a showing of an only tangential relation of the amendment to the equivalent in question or by a showing of "some other reason" that the patentee could not have been expected to describe the alleged equivalent.40
According to the Court of Appeals, the first criterion requires an objective inquiry as to whether the alleged equivalent would have been unforeseeable to one of ordinary skill in the art. Here, the court distinguished between later-developed technology (such as Velcro® in the fastener art) and old technology, that is, technology that was known in the prior art.41 Importantly, for purposes of evaluating foreseeability, the relevant time frame is when the narrowing amendment was made.42 Since this is a fact-specific inquiry by the court which scrutinizes both the state of the art and the understanding of the ordinarily skilled artisan, parties may present expert testimony as well as other extrinsic evidence to assist the court in its determination.43
The second criterion of tangentialness, according to the court, seeks "whether the reason for the narrowing amendment was peripheral, or not directly relevant, to the alleged equivalent."44 Here, the court was anticipating instances that may arise and was unequivocal as to what was not tangential, namely an amendment made to avoid prior art that reads on an equivalent.45 The tangentialness prong focuses on the patentee's "objectively apparent reason for the narrowing amendment" and accordingly, a trial court should rely solely on "the prosecution history record without the introduction of additional evidence, except, when necessary, testimony from those skilled in the art as to the interpretation of that record."46
The third criterion requires the patentee to show "some other reason" why the patentee could not reasonably be expected to have described the insubstantial substitute in question. The court recognized the vagueness of this inquiry, but stressed that it is a narrow avenue, made available only "not to totally foreclose a patentee from relying on reasons" other than the two discussed above.47 For example, shortcomings of language may be cited for why the patentee was prevented from describing the alleged infringing element during claim amendment.48 Here again, the court emphasized the role of the prosecution history record to this analysis, although not definitively foreclosing the use of extrinsic evidence.49
Turning to the amendments in the suit relative to the foregoing three criteria, the Federal Circuit held that as a factual matter, the trial court must determine whether SMC's use of an aluminum sleeve was foreseeable as to Festo's "magnetizable metal" amendment. But the court found neither "tangentialness" to nor "some other reason" for the magnetizable amendment and definitively ruled on their absence regarding the second and third criteria.51
As to the sealing rings amendment, the court again ruled that the trial court must determine whether a single, two-way sealing ring was foreseeable to Festo's amended claimed "first sealing rings," "second sealing rings" and "a pair" of resilient sealing rings.52 Similar to the "magnetizable" limitation, the court found that the "tangentialness" and "other reason" criteria were not established.53 Accordingly, the court remanded the case back to the district court for additional factual inquiry into whether Festo could rebut the foreseeability aspect of the presumption for the amended claims.54
Conclusion
The Supreme Court mandated that the Federal Circuit back-away from its "absolute bar" approach and the Federal Circuit has followed this direction. However, it appears to have done so by effectively elevating "foreseeability" to a more prominent role in rebutting a presumption of prosecution history estoppel and correspondingly limited the applicability of the other two mechanisms. Indeed, Judge Rader in his concurrence characterizes foreseeability as "the unifying principle that justifies the doctrine of equivalents even beyond the confines of rebutting estoppel presumptions."55 We can expect to see much in the way of foreseeability and unforeseeability arguments from patent litigants, both within and outside the context of a prosecution history estoppel setting.
Footnotes
1. Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., Ltd., 535 U.S. 722 (2002).
2. No. 95-1066, 2003 WL 22220526 (Fed. Cir. Sep. 26, 2003). Hereafter, Festo.
3. Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., Ltd., No. 88-1814-PBS (D. Mass. Oct. 27, 1994).
4. Festo, 2003 WL 22220526, at *10.
5. Id. at *11.
6. Id. at *11, 12. The doctrine of equivalents may be used by a patentee when literal infringement is not present. It "allows the patentee to claim those insubstantial alterations that were not captured in drafting the original patent claim, but which could be created through trivial changes." Festo, 535 U.S. at 733.
7. Supra, n.4.
8. Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., Ltd., 72 F.3d 857 (Fed. Cir. 1995), vacated and remanded, 520 U.S. 1111 (1997).
9. 520 U.S. 17 (1997).
10. Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., Ltd., 520 U.S. 1111 (1997).
11. Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., Ltd., 172 F.3d 1361 (Fed. Cir. 1999).
12. Festo Corp. V. Shoketsu Kinzoku Kogyo Kabushiki Co., Ltd., 187 F.3d 1381 (Fed. Cir. 1999).
13. Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., Ltd., 234 F.3d 558 (Fed. Cir. 2000) (en banc).
14. Id. at 563.
15. Id. at 568.
16. Id. at 564.
17. Id.
18. Id. at 591.
19. Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., Ltd., 533 U.S. 915 (2001).
20. Id. at 735-37.
21. Id. at 740.
22. Id. at 731.
23. Id. at 732.
24. Id. at 734.
25. Id. at 738.
26. Id. at 741-42.
27. Id. at 741.
28. Judge Rader wrote a concurring opinion. Judge Newman, joined by Judge Mayer, wrote an opinion concurring in part and dissenting in part.
29. Festo, 2003 WL 22220526, at *13.
30. Id.
31. Id. at *6.
32. Id.
33. Id. at *7.
34. Id.
35. Id.
36. Id.
37. Id.
38. Id.
39. Id.
40. Id. at *8-9.
41. Id. at *8.
42. Id. at *20, n.2.
43. Id. at *8.
44. Id.
45. Id. *9.
46. Id. Here, the court at first extolled the "public notice function" of the patent prosecution history as the sole source of scrutiny in an amendment situation, but then seemingly back-tracked to allow room for extrinsic evidence as well.
47. Id. at *9.
48. Id.
49. Id.
50. Id. at *10.
51. Id.
52. Id. at *11.
53. Id. at *11-12.
54. Id. at *2.
55. Id. at *13 (Rader, J., concurring).