Claims may not be Cancelled for Indefiniteness in Inter Partes Review (IPR), but the Issue of Indefiniteness Will Continue to Arise

By Seema Mehta


In Samsung Elec. Am., Inc. v. Prisua Eng’g Corp.,[1] the CAFC held that the Patent Trial and Appeals Board (PTAB) may not cancel claims in Inter Partes Review (“IPR”) on the basis of indefiniteness under 35 § USC 112.  At first glance this seems exactly the right answer:  Section 311(b) of the statute limits the grounds on which a petitioner can request an IPR to lack of novelty and non-obviousness under Sections 102 and 103, respectively.  However, Section 311(b) is silent regarding the authority of the PTAB or Director to cancel claims on any particular bases, especially when a basis such as indefiniteness renders impossible any proper claim construction, which is the first necessary step in determining the scope of challenged claims in an IPR.  Despite that silence, it is now clear that Post Grant Review (“PGR”) is the only avenue for cancellation of claims for indefiniteness under 35 U.S.C. § 112.

The PTAB has long had to deal with indefiniteness in IPR proceedings at every stage, but has always hesitated to cancel any claims based on indefiniteness, presumably due to the language of the statute.  For example, in Samsung Electronics Co. v. Huawei Technologies Co.,[2] the Board sua sponte addressed claim indefiniteness in the final written decision with respect to means-plus-functions claims that lacked proper structure associated with those claims in the specification.  Although the PTAB instituted review of the means claims post-SAS, in the final written decision, the PTAB independently reviewed the means claims, concluding that due to the lack of structure in the specification, it was “unable to construe the meaning” of those claims and, further, was unable to determine whether the claims were obvious over the prior art.  Although the claims were not cancelled, the PTAB’s comments relating to 35 USC § 112(b) casts at least some doubt on the patent owner’s ability to assert those claims successfully in any subsequent district court litigation.

Indefiniteness has also come before the PTAB in an IPR Proceeding at the institution stage, where institution can be denied if claims are indefinite, because differences between the claims and the prior art cannot be ascertained.  “‘Without ascertaining the proper claim scope, we cannot conduct a necessary factual inquiry for determining obviousness—ascertaining differences between the claimed subject matter and the prior art.’” Micron Tech. Inc. v. Innovative Memory Systems, Inc., IPR2016-00324, Paper 11 at 8-9 (PTAB June 13, 2016) (decision denying institution).

In the latest Samsung case, after being sued, Samsung petitioned for inter partes review of claims 1-4, 8 and 11 of Prisua’s ‘591 patent.  The PTAB decided to review only whether claim 11 was obvious in view of a US patent publication to Sitrick.  The PTAB declined to institute review of claims 1-4 and 8, stating that it could not determine the scope of these claims due to the fact that claim 1 was indefinite for lacking structure for “digital processing unit” and for unclear “capable of” language.  In the midst of the proceeding, SAS was decided by the CAFC (requiring “all or nothing” institution, not claim-by-claim or ground-by-ground), and the PTAB modified its institution decision to include all of the challenged claims.  Samsung then asserted that the PTAB should cancel claims 1-4 and 8 based on its prior determination that those claims were indefinite.  In contrast, Prisua argued that Samsung did not show that the claims were definite, and therefore, those claims should not be included in the PTAB’s substantive review based on prior art.

Ultimately, the CAFC held that the PTAB does not have the statutory authority to cancel claims for indefiniteness under 35 U.S.C. § 112 in an inter partes review proceeding.  The Court reasoned that the Petitioner’s petition governs the scope of the IPR proceeding (as required under SAS), and that it is not based on the Director’s discretion.  Samsung also argued that 35 U.S.C. § 318(a), relating to the final written decision, has broad language that does not limit the PTAB to only grounds that could be raised under section 102 or 103.  But the CAFC declined to interpret § 318(a) as being “divorced” from the remainder of the inter partes review statute.

With the decision in Samsung, it is clear that even though indefiniteness issues will continue to arise in IPR proceedings, the PTAB may not cancel any claims on the basis of indefiniteness under 35 U.S.C. § 112.  Thus, the PTAB may continue to deny institution based at least partially on indefiniteness, but cannot follow that path to its logical conclusion; instead, Post Grant Review is the only avenue for cancellation of claims for indefiniteness under 35 U.S.C. § 112.

[1] 948 F.3d 1342 (Fed. Cir. 2020).

[2] IPR IPR2017-01471, Paper 25 (May 24, 2017).