Linguistics and Claim Construction

Abstract:     
Despite its great importance in patent litigation and recent interest derived from the U.S. Court of Appeals for the Federal Circuit's en banc Phillips opinion, claim construction - the process of giving a patent claim meaning through defining its terms - is largely an unsettled and uncertain area of patent law. In part, this uncertainty may be due to the Federal Circuit's failure to provide adequate guidance on the process. This Article suggests that the Federal Circuit should clarify its claim construction jurisprudence, looking to the science of linguistics to provide bases for an improved set of guidelines that will improve certainty in patent law.

This Article argues that claim construction should instead track the way in which we, as readers of a language, attempt to understand what is being conveyed via the written word. First, there is a base level of conventional understanding from which all interpretation starts, an understanding that either a priori exists based on our earlier encounters with the word or is obtained from a dictionary in cases where we lack previous knowledge. Second, from this conventional understanding, we construct the actual meaning of the term based on a number of linguistic clues, both internal to the document and external from our prior experiences.

In particular, there are at least five notions from linguistics that can help shape a more consistent claim construction methodology: 1) every reader, including a judge, possesses a mental lexicon with a common sense (or conventional) understanding of word meaning which is a point from which to start when interpreting claims; 2) there is an appropriate place for dictionary usage, which is to inform the judge's common sense understanding about a word where he has none; 3) patent claims have their own grammar which must inform the syntactical and contextual analysis, but may also skew the reader's common understanding that was obtained either from a mental lexicon or from a dictionary; 4) regardless of the common sense understanding, the PHOSITA must be returned to the analysis and changes made to the law to effectuate the return of the PHOSITA; and 5) extensive resort to the specification and prosecution history to divine the patentee's intent is inappropriate.

Keywords: patent, claim, claim construction, claim interpretation

JEL Classifications: K39, K40, K41, O31, O34

Working Paper Series