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Patentee’s claim term definition comes back to haunt it

June 1, 2024
June/July 2024 Cantor Colburn IP Newsletter

Federal patent law allows a patentee to devise its own definition for a claim term — or act as its own “lexicographer” — rather than settling for the “plain and ordinary” meaning. At first glance, this may seem like an advantage for patent holders. Sometimes, though, a patentee can become a lexicographer inadvertently, with disastrous consequences.

Crossed signals

ParkerVision holds a patent related to wireless local area networks that use frequency translation technology. The patent incorporates another patent that describes two types of systems for down-converting electromagnetic (EM) signals.

Intel Corporation asked the Patent Trial and Appeal Board (PTAB) for inter partes review (IPR) of a claim in the patent. Under IPR, the PTAB can reconsider and cancel an already-issued patent based on certain types of “prior art” that made the invention obvious.

The PTAB found the challenged claim unpatentable as obvious, based in part on its interpretation of the claim term “storage element.” ParkerVision asserted that the proper meaning was “an element of an energy transfer system that stores non-negligible amounts of energy from an input electromagnetic signal.”

The board defined the term to mean “an element of a system that stores non-negligible amounts of energy from an input EM signal.” It relied on the description of a “storage module” in the incorporated patent. (The parties agreed that the term “storage module” used in the incorporated patent was synonymous with “storage element.”)

Lexicography lesson

ParkerVision appealed to the U.S. Court of Appeals for the Federal Circuit, disputing, among other things, the PTAB’s interpretation of “storage element.” But the appellate court agreed with the PTAB’s interpretation, finding that ParkerVision acted as its own lexicographer to define the term. To do so, a patentee must clearly set forth a definition of the disputed claim term that diverges from the plain and ordinary meaning. The patentee also must clearly express an intent to define the term.

The court found that ParkerVision acted as its own lexicographer in the incorporated patent to define “storage element.” In the relevant paragraph, ParkerVision clearly distinguished the definitions of “holding modules” and “holding capacitances” from the definitions of “storage modules” and “storage capacitances.” It specifically stated (emphasis added): “Storage modules and storage capacitances, on the other hand, refer to systems that store non-negligible amounts of energy from an input EM signal.”

Words matter

Notably, the court shot down ParkerVision’s argument that the sentence above was comparative, not definitional. The Federal Circuit said that a sentence being comparative doesn’t exclude the possibility that it’s also definitional. In the end, the court upheld the PTAB’s decision finding the patent claim unpatentable.

© 2024

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