Court Opinion

ID: 9499557
Source: CourtListenerOpinion
Date Created: 2023-08-05 17:51:20.577868+00
Date Added: 2024-06-11T17:59:34.661816
License: Public Domain

RADER, Circuit Judge,
concurring.
I concur with the result in this case. I write separately to address further the issue of prosecution history estoppel of claim 5 of U.S. Patent No. 5,474,555 (the '555 patent).
The district court found that Cross Medical successfully rebutted the presumption of prosecution history estoppel for claim 5 of the '555 patent based on tangentiality. Cross Med. Prods., Inc. v. Medtronic Sofamor Danek, Inc., SA CV 03-311-GLT, slip op. at 10 (C.D.Cal.2005) (Trial Court Opinion ). With that finding, the district court proceeded to determine that Medtronic’s redesigned screws (with internal threads that stopped above the top of the rod) infringe under the doctrine of equivalents. Trial Court Opinion, slip op. at 22. As noted in the majority opinion, the '555 patent applicant specifically amended its claims in response to an examiner’s rejection. The amendment specified that the first threads extend deeper than the top of the rod received in the channel of the seat. Majority Opinion, pp. 1339-40. The examiner allowed the application based on this amendment. Id. at 1340.
This prosecution history became very important when Medtronic attempted to design around claim 5. As this court has noted, Medtronic altered its original screw design to terminate the corresponding threads at a position above the rod diameter. Id. at 1340. Medtronic chose this new design with an eye to the applicant’s narrowing amendment. Nonetheless, the district court determined that this narrowing amendment to claim 5 during prosecution was only “tangentially related” to the accused equivalent and thus not subject to an estoppel. Trial Court Opinion, slip op. at 8-11; see Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., 344 F.3d 1359 (Fed.Cir.2003) (en banc). Thus, the district court found the screws infringe claim 5 under the doctrine of equivalents. Trial Court Opinion., slip op. at 11.
This court made the tangential relation criterion for overcoming the Festo presumption very narrow. Festo, 344 F.3d at 1369. Festo itself recognized that rebuttals under the tangential principle will be rare. Id. (“[W]e cannot anticipate the instances of mere tangentialness that may arise....”). Cases in the interim have confirmed Festo’s insight; only two cases have successfully invoked the tangential rebuttal principle in this court. See Insitu-form Tech. Inc. v. CAT Contracting, Inc., 385 F.3d 1360, 1368 (Fed.Cir.2004) (holding that an amendment adding a single cup bore no more than a tangential relation to the alleged equivalent containing multiple cups); Primos, Inc. v. Hunter’s Specialties, Inc., 451 F.3d 841, 849 (Fed.Cir.2006) (finding that the “territory surrendered” by a claim amendment requiring a plate to be “differentially spaced” did not bar equivalence to a dome-shaped structure). The facts of Insituform and Primos arguably related to situations where the prosecution history clearly demonstrated that the alleged equivalent and the narrowing amendment implicate entirely different as*1347pects of the invention. Yet in reading those cases, frankly, this court might well have justifiably reached a different result in both. For example, in Insituform, this court seems to assume that the number of sources bears no relation to the location of those multiple sources. A contrary conclusion might have noted that anytime a technology adds another source it must also add another location for that new source. Multiple sources and locations for those sources would seem logically related.
In my view, the tangential rebuttal principle exacerbates the policy deficiencies of the doctrine of equivalents. Upon invoking tangentiality, the patentee has already admitted that the equivalent falls within the scope of surrendered subject matter. Further, if the case permitted, any patentee would invoke the primary “foreseeability” rebuttal factor. Thus, an invocation of “tangentiality” often admits that the equivalent was both within the scope of the surrender and foreseeable at the time of prosecution. In other words, the patent drafter could have claimed the surrendered and foreseeable technology, but declined to do so.
Furthermore, the tangentiality rebuttal principle, by its nature, undermines principles of public notice. This rebuttal principle operates because the patentee has expounded very different purposes for its narrowing amendment than those applicable to the tangential equivalent. The prosecution record thus does not address this “tangential” equivalent (which nonetheless was surrendered and was known and claimable during prosecution). In other words, the patentee gets a reward — coverage under the doctrine of equivalents— precisely because its explanations did not give the public any notice of the unclaimed and surrendered subject matter. The public might have believed it could practice technology that the patentee surrendered in prosecution. Moreover, the public might have reasonably undertaken to practice that foreseeable technology because the patentee could have claimed it but declined to do so. Even beyond these principles, the public might have consulted the prosecution history and learned that the patentee gave no explanation for its surrender of this foreseeable technology. Thus, a diligent study of the patent and its prosecution history would give the public every reason to believe that the “tangential” subject matter would fall outside the scope of the invention and within the public domain. The basic principles of public notice would suggest these unclaimed and surrendered “tangential” technologies have no conceivable basis to expect patent protection.
This case is a classic example of the tangentiality principle running counter to principles of public notice. Medtronic had suffered an injunction. It deliberately sought to design around the patented technology — a response that patent law encourages. State Indus. Inc. v. A.O. Smith Corp., 751 F.2d 1226, 1236 (Fed.Cir.1985) (“One of the benefits of a patent system is its so-called ‘negative incentive’ to ‘design around’ a competitor’s products, even when they are patented, thus bringing a steady flow of innovations to the marketplace.”). It undoubtedly consulted the patent and adjusted its technology with reference to the claim language and prosecution history of the patent. Then, after it adopted unclaimed technology that the patentee had deliberately surrendered to the public, it finds itself again subject to an injunction. Tangentiality thus, as in this case, can defeat principles of notice and proper procedures for designing around patented technology. Medtronic’s situation illustrates the difficulties of a broad application of tangentiality.
*1348This “tangential” rebuttal principle becomes even more difficult in practice. What neutral standard makes some surrendered and unclaimed technologies infringing equivalents while others enjoy no protection? This tangential concept has no analogue in patent law. How tangential does it have to be?
In any event, this case reaffirms that the tangential rebuttal principle remains very narrow. See Biagro W. Sales, Inc. v. Grow More, Inc., 423 F.3d 1296, 1306 (Fed.Cir.2006) (distinguishing Insituform as limited to situations in which the prosecution history clearly demonstrates that “the amendment and alleged equivalent involve different aspects of the invention”). Biagro thus explains that the factual circumstances that could give rise to the tangential rebuttal principle will very rarely occur (even less often successfully). Biagro emphasizes that the evidence of tangen-tiality must appear in the prosecution history in order to prevent litigation-driven or hindsight reconstruction of the reasons for an amendment. The applicant is not likely to have made a prosecution record that makes some subject matter (the equivalent) tangential to the purpose for the rest of the amendment. See Kenneth D. Bassinger, Unsettled Expectations in Patent Law: Festo & The Moving Target of Claim Equivalence, 48 How. L.J. 685, 720 (2005) (“Unfortunately, if the reason for an amendment is truly tangential in nature, it is not likely to be found in the prosecution history.”); Martha M. Rumore, Ranbaxy Pharms. v. Apotex: Redefining Claim Drafting and Patent Prosecution Under Festo, 22 No. 4 Intell. Prop. L. Newsl. (ABA), Summer 2004, at 12, 13 (questioning whether there is, in practice, a separate tangential relation criterion or whether the three criteria established in Festo really boil down to simply an all encompassing foreseeability test). In any event, I would reemphasize that the application of the tangentiality factor in this case preserves the Biagro narrowness principle and stress that tangentiality always threatens the public notice that enables designing around.