The USPTO has updated the training it gives its patent examiners this spring to clarify the terms used in the prosecution of a patent. The guidelines explain that “the PTAB and courts will be informed as to what the examiner and the applicant understood the claims to mean.” The goal of the new initiative is to provide “a clear file history [to] prevent or reduce unnecessary litigation, interferences, reissues, ex parte reexaminations, inter partes reviews, supplemental examinations, and post-grant proceedings.”
Under MPEP § 2111, “During patent examination, the pending claims must be “given their broadest reasonable interpretation consistent with the specification.” ” Because the applicant can amend the claims during prosecution, giving a claim its broadest reasonable interpretation reduces the possibility that the courts, the patentee, or others may interpret it more broadly than is justified. However, “[t]he broadest reasonable interpretation of the claims must … be consistent with the interpretation that those skilled in the art would reach.”
Against that backdrop, we have MPEP 2111.01, which tells us that “Under a broadest reasonable interpretation, words of the claim must be given their plain meaning, unless such meaning is inconsistent with the specification. The plain meaning of a term means the ordinary and customary meaning given to the term by those of ordinary skill in the art at the time of the invention. The ordinary and customary meaning of a term may be evidenced by a variety of sources, including the words of the claims themselves, the specification, drawings, and prior art. However, the best source for determining the meaning of a claim term is the specification – the greatest clarity is obtained when the specification serves as a glossary for the claim terms. The presumption that a term is given its ordinary and customary meaning may be rebutted by the applicant by clearly setting forth a different definition of the term in the specification.” Thus, the plain meaning of any term may be redefined by the patentee within the four corners of the patent application, and the examiner must interpret the term as that term is interpreted by the patentee.
Including a glossary in your application is good practice that patent applicants often fail to do. By including a glossary in your application as part of the specification, you become your own lexicographer and define terms, even terms whose plain meaning is otherwise clear, in the way in which you want those terms to be interpreted by the USPTO and by the courts.
A “broadest reasonable interpretation” may be limited under 35 USC 112(f), which states, “Element in Claim for a Combination.— An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof.”
The plain-meaning vs. means-plus-function claim interpretation is only one of the reasons why you don’t want to write a patent application yourself.