On 26 September 2017, the Federal Circuit reversed a PTAB decision—which had affirmed all of the examiner’s rejections of patent claims in an ex parte reexamination—because the PTAB adopted an “unreasonably broad” interpretation of a claim term.[1] The Federal Circuit provided the following guidance on the proper application of the “broadest reasonable interpretation” standard at the PTAB:

  • The “protocol of giving claims their broadest reasonable interpretation . . . does not include giving claims a legally incorrect interpretation” “divorced from the specification and the record evidence.”
  • The proper standard is to determine a claim term’s broadest reasonable interpretation, and not its broadest possible interpretation. In the underlying proceeding, the PTAB agreed with the examiner’s broad construction of “body,” the disputed term, by emphasizing that (1) the patent applicant had not acted as a lexicographer, and (2) the specification neither defined nor precluded the broad interpretation taken by the examiner. The PTAB reasoned that nothing in the specification would disallow the examiner’s interpretation of “body,” rendering it “reasonable.” The Federal Circuit rejected the PTAB’s rationale and admonished that, under the PTAB’s logic, “any description short of an express definition or disclaimer in the specification would result in an adoption of a broadest possible interpretation of the claim term, irrespective of repeated and consistent descriptions in the specification that indicate otherwise.”
  • In other words, the fact that the specification does not “in and of itself proscribe the Examiner’s construction” does not necessarily make that interpretation reasonable.
  • The correct way for determining a claim term’s “broadest reasonable interpretation” is thus not to exclude only what the specification proscribes or precludes as an interpretation, but to interpret the term in a way that corresponds with how the inventor describes his invention in the specification, i.e., an interpretation that is “consistent with the specification.” And the specification in this case, according to the Federal Circuit, consistently disclosed the “body” as a component distinct from other components that would have been encompassed under the PTAB’s “unreasonably broad” construction.

The Federal Circuit’s decision provides a meaningful reminder on the limits of the claim construction principles of the “broadest reasonable interpretation” standard, particularly that the standard requires an interpretation that is consistent with the specification, and not merely an interpretation that is not proscribed or precluded by the specification.