When Common Words Can Create Problems in Patents

By Barry R. Lewin

In patent applications, it is critically important to use well-defined terminology. Patent applications are comprised of words and pictures which both describe the invention and state the proposed scope of protection. Both the words and the pictures should be crystal clear, but at times, some selected words might have multiple meanings or be nuanced. Issues can crop up when multiple interpretations are possible, even if the Applicant did not intend for multiple meanings to exist. An Applicant is allowed to be his or her own lexicographer and can use the specification to define terms used in a claim. If a term is not defined explicitly, someone taking a very literal reading could read an unanticipated meaning into a word, a phrase, or even an element of an apparatus.

In order to obtain patent protection, the claims of a patent application need to be both novel and not obvious over prior inventions (among other criteria). An Examiner, a Patent Office employee skilled in the relevant technology, compares or examines the claims of a patent application to determine if they are both novel and not obvious over prior inventions as described in published documents, such as earlier patents, that preceded the present application. For an Examiner to determine if these criteria are met, the Examiner may need to interpret terminology in a claim.

Although an Applicant might think the description might be clear, any and all words might be open to interpretation. Under Patent Office rules, an Examiner is required to take “the broadest reasonable interpretation” (“BRI”) of a “person of ordinary skill in the art.” But what is the “broadest reasonable interpretation?” How broad is it and when does it become too broad?

To interpret the claim, the Examiner must primarily rely on how the term is described or defined in the specification, if it is defined or described. But if the Applicant leaves a term undefined, an Examiner ordinarily uses a plain meaning of the term as his/her way of implementing the BRI standard. This can be a problem if the plain meaning could have multiple meanings. Often, simple words are left undefined.

In a recent case before the Court of Appeals for the Federal Circuit, In Re: Smith Int’l, Inc. Appeal 2016-2303 (Fed. Cir., Sept. 16, 2017), the meaning of the term “body” in claims for a mechanical device patent was questioned. Several claims were directed to a mechanical assembly, where one element was “a body”. The term “body” was found in the specification, but it was not defined in an especially limiting way. Of course, “body” is an open-ended term, subject to how it might be used in the specification. During a reexamination, the Patent Appeal Board determined that the term “body” was a generic term and there was no structural specificity identified in the specification and disallowed the claims.

On appeal, the Court reversed and noted that even though the patent specification and claims failed to elaborate on what the body precisely encompassed, the term was not used in the specification in a generic manner, in contrast to the conclusion of the Patent Appeal Board. The Court further noted that a body was described distinctly from other elements of the invention, suggesting that it at least had some uniqueness in its meaning, relying in part on the figures in the patent. The Court noted that under BRI, the interpretation must conform to the description as used. In this case, the Applicant had not acted as a lexicographer relative to “body,” but that reasoning alone was insufficient to read the term “body” overly broad.

So what are the learnings to take from this case? First, in preparing a patent it is important not to assume a term will be defined similarly by everyone, including Examiners and later challengers to a patent. Multiple meanings of common terms can result in unanticipated ambiguities. And because Examiners are trained to seek the “broadest reasonable interpretation,” they will often assume a common term may have multiple meanings when it is reasonable for them to do so. Second, it is usually a good idea to act as a lexicographer in a patent application, particularly when terms can be read in multiple different ways. Finally, it is a good idea to define terms broadly when they are intended to be defined broadly and define them narrowly when they are intended to be defined that way. For example, one could define the body as “including any and all elements shown in Fig. 1.”