There are a number of requirements that must be met for an invention to be patentable. The invention must be novel (unique) and nonobvious (i.e., a person skilled in the field of the invention would not have found the invention obvious based on the existing knowledge in the field). In addition, the patent application must meet other requirements, including written description (the application must contain a detailed, clear, and definite written description of the invention) and enablement (the application must describe how to make and use the invention). If the patent application satisfies all of the requirements, a patent is issued.
A third party can challenge an issued patent on several different grounds, either in litigation or in the Patent and Trademark Office’s Patent Trial and Appeal Board (PTAB). If the challenge is successful, some or all of the patent’s claims will be invalidated. If only some of the claims are invalidated, those claims will be canceled from the patent and the remaining claims will be enforceable.
An inter partes review (IPR) is one of the procedures used to challenge a patent in the PTAB. In an IPR, however, the challenger may only assert two grounds of invalidity: novelty and nonobviousness. In ruling on an IPR, the PTAB cannot invalidate the patent on any other grounds.
This issue was recently addressed by the Federal Circuit Court of Appeals in Samsung Electronics America, Inc. v. Prisua Engineering Corp, 2020 U.S. App. LEXIS 3292 (February 4, 2020). Prisua obtained a patent for editing a video data stream, and sued Samsung for patent infringement. Prisua alleged that Samsung’s cell phones and other devices used Prisua’s patented technology. The jury found that Samsung had willfully infringed Prisua’s patent, and awarded Prisua damages of $4.3 million. The action was then stayed because, in the meantime, Samsung had filed a petition in the PTAB for IPR.
In its petition, Samsung challenged several claims of Prisua’s patent on obviousness grounds. The PTAB invalidated one claim as obvious, but said that it could not review the other claims for obviousness because those claims were indefinite (i.e., not clear). The PTAB said that it could not determine the scope of those claims, and therefore could not determine whether those claims were obvious.
Samsung appealed. On appeal, Samsung argued that the PTAB should have either invalidated the indefinite claims, because definiteness is also a requirement for a patent, or gone ahead and determined whether the claims were obvious even if their scope could not be determined. Prisua argued that the patent statutes do not permit the PTAB to invalidate claims for indefiniteness in an IPR.
The Federal Circuit agreed with Prisua. The court held that in an IPR, the PTAB can only invalidate a patent’s claims on the grounds of novelty and nonobviousness; it cannot invalidate a claim for indefiniteness. The court also held that the PTAB should determine whether a challenged claim is obvious even if it is indefinite.
Thus, the court made it clear that an IPR can only be used to challenge a patent for novelty and nonobviousness. The patent statutes do not authorize the PTAB to decide indefiniteness in an IPR. There are other procedures that a challenger can use for that purpose.