Inter partes review (IPR) is an expedited procedure before the Patent Trial and Appeal Board (PTAB) that allows a party to challenge the patentability of a U.S. patent. While an IPR may provide an accelerated process for challenging a patent, IPRs also carry estoppel provisions. Specifically, under 35 U.S.C. § 315(e), IPR petitioners are estopped from asserting in other forums "that the claim is invalid on any ground that the petitioner raised or reasonably could have raised during that inter partes review."
多方复审（IPR）是专利审判和上诉委员会（PTAB）所进行的一种加速程序，该程序允许一方当事人对美国专利的可专利性提出质疑。虽然IPR可能为质疑专利提供一个加速的流程，但IPR也带有禁反言的规定。具体而言，根据《美国法典》第35编第315（e）条，IPR的请求人被禁止在其他诉讼平台上主张“该权利要求基于请求人在该IPR期间已经提出或合理情况下本可以提出的任何理由而无效”。
1.背景
In an IPR, petitioners may only raise unpatentability challenges "under section 102 or 103 and only on the basis of prior art consisting of patents or printed publications." A petitioner cannot use non-publication system prior art—a system, device, or product that practices the invention described in a challenged patent—in an IPR. However, system prior art can be used to argue patent invalidity in district court proceedings. While petitioners are estopped from re-litigating grounds that were raised or reasonably could have been raised in the IPR, district courts, and even judges within districts, are split on how to apply IPR estoppel to system prior art. Some district courts have found that system prior art is a distinct ground from a patent or printed publication related to the system prior art, and therefore IPR estoppel does not apply. Other district courts have found that a petitioner may be estopped from using system prior art in certain circumstances.
在IPR程序中，请求人仅可“依据第102条或第103条，且仅基于由专利或印刷出版物构成的现有技术”对专利的不可专利性提出质疑。请求人在IPR程序中不能使用未公开的系统现有技术，即实施了有争议专利中所描述发明的系统、装置或产品。然而，系统现有技术可用于在地区法院诉讼中主张专利无效。虽然请求人被禁止就已在IPR程序中提出或本可合理提出的理由再次进行诉讼，但地区法院，甚至同一地区内的不同法官，对于如何将IPR的禁反言原则应用于系统现有技术存在意见分歧。一些地区法院认为，系统现有技术是与该系统现有技术相关的专利或印刷出版物不同的依据，因此IPR的禁反言原则不适用。而其他地区法院则认为，在某些情况下，请求人可能会被禁止使用系统现有技术。
2.特拉华州地区法院
The District of Delaware is split on the issue of IPR estoppel based on system prior art.
特拉华州地区法院在基于系统现有技术的IPR禁反言问题上存在意见分歧。
In Wasica Finance GmbH v. Schrader International, Inc., Judge Stark addressed whether an obviousness combination that included a physical product "where all the relevant features of that physical product had been disclosed in a patent or printed publication that reasonably could have been raised during the IPR" is estopped under 35 U.S.C. § 315(e).While Judge Stark found "both parties' interpretations of the statutory scheme reasonable," he ultimately held that IPR estoppel applied to the physical product being used in the obviousness combination. Judge Stark reasoned that 35 U.S.C. § 312(a)(3) "distinguishes between grounds and evidence" and because the estoppel provision of § 315(e) applies to grounds, a petitioner "is estopped from proceeding in litigation on those grounds, even if the evidence used to support those grounds was not available to be used in the IPR."Accordingly, Judge Stark ruled that IPR estoppel applied to the prior art products asserted by Schrader.
在“Wasica诉Schrader”一案中，斯塔克法官审理了这样一个问题：对于一种包含实体产品的显而易见性组合，若“该实体产品的所有相关特征已在一项专利或印刷出版物中披露，且该专利或印刷出版物在IPR期间本可合理地被提出”，那么根据《美国法典》第35编第315（e）条，这种情况是否属于禁反言的范畴。虽然斯塔克法官认为“双方对法定体系的解释都具有合理性”，但他最终判定，IPR的禁反言适用于在该显而易见性组合中所使用的实体产品。斯塔克法官解释称，《美国法典》第35编第312（a）（3）条“对理由和证据进行了区分”，并且由于第315（e）条的禁反言规定适用于理由，所以请求人“被禁止基于那些理由进行诉讼，即便用于支持这些理由的证据在IPR中无法使用”。因此，斯塔克法官裁定，IPR的禁反言适用于Schrader公司所主张的现有技术产品。
In Chemours Co. v. Daikin Ind. Ltd., Chemours argued that the prior-art products raised by Daikin were "cumulative" of the paper art that was asserted during corresponding IPR proceedings, and therefore IPR estoppel applied. Judge Noreika, unlike Judge Stark, found that "[a]s a matter of statutory interpretation, estoppel does not apply to [] prior art products."Judge Noreika reasoned that "Congress could have broadened the categories of prior art on which IPR could be requested" or "could have dictated that estoppel applies to products covered by the paper art underlying the IPR," but Congress did not do so. Accordingly, Judge Noreika found that IPR estoppel did not apply to the prior-art products asserted by Daikin.
在“Chemours诉Daikin”一案中，Chemour公司辩称，Daikin公司提出的现有技术产品是相应IPR程序中所主张的书面现有技术的“重复”内容，因此IPR的禁反言原则应当适用。与斯塔克法官不同，诺雷卡法官认为，“从法律解释的角度来看，禁反言原则并不适用于现有技术产品”。诺雷卡法官解释称，“国会本可以扩大可请求进行IPR所基于的现有技术类别”，或者“本可以规定禁反言原则适用于作为IPR基础的书面现有技术所涵盖的产品”，但国会并未这么做。因此，诺雷卡法官判定，IPR的禁反言原则不适用于Daikin公司所主张的现有技术产品。
Judge Andrews, agreeing with Judge Noreika's position in Chemours, "interpret[ed] 'ground,' as that term is used in 35 U.S.C. § 315(e)(2), to mean the specific piece of prior art or combination of prior art that a petitioner raised, or could have raised, to challenge the validity of a patent claim during an IPR" and has held that § 315(e) does not estop a litigant from raising invalidity theories that rely on system prior art. Judge Williams has similarly found that IPR estoppel does not apply to system prior art, citing Judge Noreika's reasoning in Chemours.
安德鲁斯法官赞同诺雷卡法官在“Chemours案”中的立场，他“将《美国法典》第35编第315（e）（2）条中所使用的‘依据’这一术语，解释为请求人在IPR期间提出或本可以提出的、用于质疑专利权利要求有效性的特定现有技术或现有技术组合”，并认为第315（e）条并不禁止诉讼当事人提出依赖于系统现有技术的无效理论。威廉姆斯法官同样认为，IPR的禁反言原则不适用于系统现有技术，他援引了诺雷卡法官在“Chemours案”中的推理。
3.德克萨斯州东区法院
The Eastern District of Texas has generally aligned with Judge Noreika's decision in Chemours. In Biscotti Inc. v. Microsoft Corp., the court found that IPR estoppel did not apply to the system prior art asserted by Microsoft. The court reasoned that Microsoft could not have raised the system prior art asserted in the district court litigation during the corresponding IPR because § 311(b) limits IPR challenges to patents and printed publications. However, the court noted that if the "purported system prior art relies on or is based on patents or printed publications that Microsoft would otherwise be estopped from pursuing at trial" then Microsoft may be otherwise estopped from presenting those patents or printed publications at the district court.
德克萨斯州东区法院总体上与诺雷卡法官在“Chemours案”中的裁决意见一致。在“Biscotti诉微软公司”一案中，法院认定，IPR的禁反言原则不适用于微软公司所主张的系统现有技术。法院的理由是，微软公司在相应的IPR程序中无法提出其在地区法院诉讼中所主张的系统现有技术，因为《美国法典》第35编第311（b）条将IPR的质疑范围限制在专利和印刷出版物上。不过，法院指出，如果“所谓的系统现有技术依赖或基于那些在其他情况下微软会被禁止在审判中采用的专利或印刷出版物”，那么在其他方面，微软可能会被禁止在地区法院出示那些专利或印刷出版物。
The Eastern District of Texas court further expanded on this point in General Access Solutions, Ltd. v. Sprint Spectrum. While the court noted that IPR estoppel applies only to invalidity defenses based on patents or printed publications, it also explained that if a petitioner "is using its system prior art as a Trojan horse for printed subject matter" then they may be estopped under§315(e).The court warned that when "a party asserts a prior art system and relies exclusively on printed subject matter that it could have raised in IPR, it is not asserting a system at all."
德克萨斯州东区法院在“General Access诉Sprint”一案中进一步阐述了这一点。法院指出，IPR的禁反言原则仅适用于基于专利或印刷出版物的无效抗辩，同时也解释称，如果请求人“将其系统现有技术用作印刷内容的‘特洛伊木马’（暗指以系统现有技术为幌子，实质利用印刷内容）”，那么根据第315（e）条，他们可能会被禁反言。法院警告称，当“一方当事人主张一项现有技术系统，且完全依赖其本可在IPR中提出的印刷内容时，实际上它根本不是在主张一项系统”。
4.加州中区法院
The Central District of California has considered whether IPR estoppel applies to system prior art using different approaches.
美国加州中区法院采用了不同的方法来考量IPR的禁反言原则是否适用于系统现有技术。
In Star Envirotech, Inc. v. Redline Detection, LLC, the court applied a "superior and separate" analysis. Here, Plaintiffs argued that Defendants were estopped from asserting system prior art because they could have used the system's owner's manual during the corresponding IPR.The Court found that Defendants were not estopped from asserting the system prior art because "the physical machine itself discloses features . . . that are not included in the instruction manual, and it is therefore a superior and separate reference."
在“Star Envirotech诉Redline Detection”一案中，法院采用了“更优且独立”的分析方法。在此案中，原告方主张被告方被禁止提出系统现有技术相关主张，理由是被告方本可以在相应的IPR程序中使用该系统的用户手册。但法院认定，被告方未被禁止提出系统现有技术相关主张，因为“实体机器本身揭示出了一些特征……这些特征并未包含在用户手册中，因此，该实体机器是一个更优且独立的参考依据”。
In California Institute of Technology v. Broadcom Ltd., the court similarly found that IPR estoppel did not apply to system prior art, but used a different approach. Here, the court found that the "superior and separate" analysis "would likely extend the reach of statutory IPR estoppel beyond its intended scope."
在“加州理工学院诉博通公司”一案中，法院同样判定IPR的禁反言原则不适用于系统现有技术，但采用了不同的分析方法。在此案中，法院认为，“更优且独立”的分析方法“很可能会使法定的IPR禁反言的适用范围超出其预期的范畴”。
Instead, the court found that IPR estoppel would apply "if a patent challenge is simply swapping labels for what is otherwise a patent or printed publication invalidity ground in order to 'cloak' its prior art ground and 'skirt' estoppel."
相反，法院认为，如果一项专利质疑仅仅是为了“掩盖”其现有技术依据并“规避”禁反言，而只是对原本属于专利或印刷出版物无效理由的内容更换了说法，那么IPR的禁反言原则将适用。
5.结论
The Federal Circuit has not yet provided guidance on the scope of estoppel under § 315(e) as it applies to system prior art. Because district courts, and judges within district courts, are split on the scope of IPR estoppel, litigants should carefully consider relying on patents or printed publications in a corresponding IPR that relate to products or systems that may be used in the district court.
联邦巡回上诉法院尚未就《美国法典》第35编第315（e）条项下的禁反言原则在适用于系统现有技术时的范围提供指导意见。由于各地区法院以及地区法院内部的法官们在IPR禁反言的范围问题上存在意见分歧，诉讼当事人应当谨慎考虑，对于可能在地区法院使用的产品或系统，在相应的IPR中所依据的专利或印刷出版物的情况。