TAKEAWAY: Means-plus-function claiming, under 35 U.S.C. § 112(f), remains a tool in the claim drafting toolbox, but requires care when crafting an accompanying specification. Additionally, positions taken during prosecution and before other regulatory bodies may affect claim construction.

On April 14, 2017, the Federal Circuit in Core Wireless Licensing v. Apple Inc. affirmed the trial court’s denial of the patentee’s, Core Wireless, motion for judgment as a matter of law with respect to alleged infringement of a means-plus-function claim. Core Wireless argued that its means-plus-function claim did not require that a “means for comparing” values of a parameter for “channel selection” limitation be performed by a mobile device, but rather may be performed by a network. 35 U.S.C. § 112, sixth paragraph (now §112(f) under the AIA) states that means-plus-function claims are “construed to cover the corresponding structure, material, or acts described in the specification and equivalents there of.” According to Core Wireless, the channel selection steps of the patent simply described preferred embodiments, and the claim at issue did not require the channel selection step to occur in the mobile device. However, each embodiment discussed in the specification included the channel selection step being performed in the mobile device. In a brief filed during the prosecution of the patent, Core Wireless described the invention as including the channel selection being made by the mobile device. Moreover, before the European Telecommunications Standards Institute, the inventor stated that the mobile device itself makes the channel selection decision in order to more efficiently send and receive data. As such, the Federal Circuit upheld the trial court’s noninfringement ruling on the basis of the allegedly infringing mobile device not being capable of performing the channel selection step.

Means-plus-function claims provide a more narrow scope of protection, but can be a worthwhile option in claim drafting. In particular, the functional limitations of a means-plus-function claim may be useful in prosecution to overcome prior art that may be similar but incapable of performing the claimed function. Nevertheless, Core Wireless provides a noteworthy reminder that the claims cannot reach significantly beyond the scope of the express structure of the specification. Therefore, in drafting a patent application, it is important to describe alternative embodiments in the specification, as well as to draft claims having varied scopes (i.e., with means-plus-function and without). Lastly, the opinion instructs that both practitioners and inventors should be aware that any statements made about the essence or merits of a particular invention may later affect claim construction. In particular, extrinsic evidence, such as statements to other government or regulatory agencies, may influence claim construction in litigation.