Addressing a decision by the US Patent and Trademark Office’s Patent Trial and Appeal Board (Board) declining to find certain claims unpatentable because they contained means-plus-function elements without any corresponding disclosed structure, the US Court of Appeals for the Federal Circuit affirmed the Board’s decision except as to one challenged claim where the means-plus-function element was recited as an alternative to a non-means-plus-function element. Cochlear Bone Anchored Solutions AB v. Oticon Medical, AB, Case Nos. 19-1105, -1106 (Fed. Cir. May 15, 2020) (Taranto, J.).

Cochlear sued Oticon for infringement of four patents related to hearing devices. In response, Oticon filed two inter partes review petitions against all claims of one of the patents. The Board initially declined to institute review as to four of the challenged claims that contain means-plus-function elements without the required corresponding structure identified in the specification, but the Board later added those means-plus-function claims to the proceedings in view of the Supreme Court’s ruling against partial institutions in SAS Institute v. Iancu (IP Update, Vol. 21, No. 5). Cochlear statutorily disclaimed four of the challenged claims during the proceedings, and the Board ultimately found all of the remaining claims to be unpatentable except for the means-plus-function claims. As to those, the Board held that it could not apply the prior art because the means-plus-function elements lacked any corresponding disclosed structure. Both parties appealed.

On appeal, the Federal Circuit first considered the claims found unpatentable and agreed with the Board’s underlying claim constructions. The Court then turned to the means-plus-function claims and agreed that a prior art-based invalidity analysis cannot be conducted on claims containing undefined claim limitations, such as means-plus-function elements without corresponding disclosed structure. The Court agreed with the Board that the means-plus-function elements lacked corresponding structure and, while not within the purview of the Board’s inter partes reviews, concluded that those claims are indefinite. However, the Federal Circuit separately considered one of the means-plus-function claims where the means-plus-function element was recited as one of two alternative structures, with the other option not written in means-plus-function format. The Court concluded that, even though that claim is indefinite due to its means-plus-function element, a prior art analysis could still be possible due to the non-means-plus-function alternative. The Court therefore remanded to the Board with instructions to carry out that analysis.