The CAFC has recently focused attention on the use of functional claim language—that is, claim language that describes what an element does, rather than describing what the element is. A recent IPR showed how functional claiming can play out at the PTAB, where it is often the case that neither the petitioner nor the patent owner wants the claims to be construed as employing “means-plus-function” language. For the petitioner, such an interpretation would make it more difficult to show invalidity. For the patent owner, such an interpretation could substantially narrow the scope of the claim and have a significant downstream impact on the patent owner’s ability to show infringement. But the PTAB may have its own ideas about how to interpret the claims.

The CAFC issued an en banc decision in 2015 that dramatically broadened the circumstances under which functional claims should be construed using a “means-plus-function” analysis. In Williamson v. Citrix Online, LLC, which we wrote about last year, the CAFC overturned prior decisions holding that the absence of the phrase “means for” establishes a strong presumption that means-plus-function analysis should not apply, and held that, in situations in which “means for” is absent, a “balanced scale” should be used to determine whether one of ordinary skill in the art would interpret the claimed feature as reciting “sufficiently definite structure” for performing the claimed function. If such structure is absent, the courts will construe the feature using means-plus-function analysis. When a claimed feature is construed using means-plus-function analysis, the scope of the claimed feature corresponds to the specific examples disclosed in the specification and their equivalents, which is generally much narrower than the scope that would be afforded to the claimed feature outside the means-plus-function framework.

Earlier this month, the Board provided some insight regarding how the Williamson decision will impact claim construction at the PTAB (IPR2016-00356). The claims of U.S. Patent No. 9,056,475 are directed to an inkjet printer comprising “a web-feeding mechanism.” Neither the petitioner nor the patent owner offered an interpretation of the claimed “web-feeding mechanism.” Moreover, the scope of this feature was not substantively addressed during the prosecution of the patent. Nonetheless, the PTAB deemed the claimed “web-feeding mechanism” did not recite sufficiently definite structure to escape a means-plus-function construction. The PTAB dismissed the petition, reasoning that, because the petitioner did not demonstrate that the prior art disclosed the corresponding structure described in the patent owner’s specification, the petitioner failed to demonstrate that the patent owner’s claims were invalid.

Interestingly, in this decision, the Board adopted a much narrower claim construction than was proposed by both the petitioner and the patent owner. As recently confirmed by the U.S. Supreme Court in Cuozzo Speed v. Lee, in IPR proceedings, the Board should construe claims according to their “broadest reasonable interpretation,” similar to the standard employed by the Patent Office during examination, and substantially different from the narrower “plain and ordinary meaning” standard employed by courts during litigation. One might expect that, in most instances, the broadest reasonable interpretation standard would lead to the Board adopting a claim construction that is much broader than that proposed by the patent owner. This case demonstrates that the Board will not always adopt a broad construction.

It is also interesting to note that, during the prosecution of the ‘475 patent, the Patent Office did not apply means-plus-function analysis to the claimed “web-feeding mechanism.” The examiner did, however, apply means-plus-function-type analysis to the recitation of a “maintenance member being configured for urging,” which was recited in an earlier version of the issued independent claim. This case reminds applicants that the Board will not be bound by the examiner’s analysis during prosecution, and that claim language should be carefully reviewed.

Takeaways: The issues in this case present a tough choice for a petitioner that wants a claim with a limitation expressed using functional language interpreted broadly to more easily show that it is invalid. In such situations, the Board might view the claimed limitation as a means-plus-function limitation and deny institution if the petitioner fails to identify corresponding structure in the specification. This case also highlights a tough choice faced by patent owners in such situations. While the Board’s adoption of a means-plus-function analysis helped the patent owner avoid a trial that could have resulted in cancellation of its claims, the Board’s interpretation also substantially narrowed the scope of the claim, which may limit the downstream value of it.