This now appears to be the seminal case regarding invocation of means-plus-function limitations under 35 U.S.C. § 112, ¶6. In summing up the case law to this point, it states that “[t]hese cases teach that, if a limitation recites a term with a known structural meaning, or recites either a known or generic term with a sufficient description of its operation, the presumption against means-plus-function claiming remains intact.” It also contains a number of statements that may be useful to cite during prosecution. For example, regarding the presumption that means-plus-function does not apply in the absence of the term “means”: “We have repeatedly characterized this presumption as strong and not readily overcome and, as such, have seldom held that a limitation without recitation of ‘means’ is a means-plus function limitation.” (Internal quotations omitted.) Regarding deference to the applicant’s intent: “Whether to draft a claim in broad structural terms is the claim drafter’s choice, and any resulting risk that emanates from that choice is not a basis for the court [or PTO] to rewrite a claim in means-plus-function format.” Regarding the corresponding structure for computer-implemented means-plus-function claims: “Aristocrat and related cases hold that, if a patentee has invoked computer-implemented means-plus-function claiming, the corresponding structure in the specification for the computer-implemented function must be an algorithm unless a general purpose computer is sufficient for performing the function.”
Background / Facts: The main patent at issue here is directed to the use of finger contacts to control a touchscreen computer device. The claims recite instructions for applying one or more “heuristics” to the finger contacts to determine a command for the device. The district court found that the claim term “heuristic” is not indefinite, instead construing it as “one or more rules to be applied to data to assist in drawing inferences from that data.”
Issue(s): Whether the “heuristic” limitations describe functions without describing the structure necessary to perform the functions such that these claim limitations are means-plus-function limitations under 35 U.S.C. § 112, ¶6, despite not reciting the word “means.”
Holding(s): No. “The correct inquiry, when ‘means’ is absent from a limitation, is whether the limitation, read in light of the remaining claim language, specification, prosecution history, and relevant extrinsic evidence, has sufficiently definite structure to a person of ordinary skill in the art.” Keeping in mind that “’[s]tructure’ to a person of ordinary skill in the art of computer-implemented inventions may differ from more traditional, mechanical structure, … [a] limitation has sufficient structure when it recites a claim term with a structural definition that is either provided in the specification or generally known in the art.” Moreover, “[s]tructure may also be provided by describing the claim limitation’s operation, such as its input, output, or connections. The limitation’s operation is more than just its function; it is how the function is achieved in the context of the invention.” In this case, “[w]e find that ‘heuristic’ has a known meaning and the [] patent also describes the limitation’s operation, including its input, output, and how its output may be achieved. Accordingly, the heuristic claim limitations recited above have ‘sufficiently definite structure,’ to a person of ordinary skill in the art, for performing the recited functions.”