An element in a patent claim may be expressed as a means or step for performing a specified function. However, 35 USC §112(f) states that a claim limitation expressed in means-plus-function form “shall be construed to cover the corresponding structure . . . described in the specification and equivalents thereof.” Software is often claimed as a sequence of steps, and it is often not clear when software claims invoke the means-plus-function requirements of 35 USC §112(f). Under guidance issued earlier this year, the US Patent and Trademark Office clarified that it will now invoke the means-plus-function requirements of §112(f) when:
When claim drafting, avoid the §112(f) trap by avoiding generic placeholders, e,g. “a software module comprising software instructions.” Also modify each element with applicable substeps in sufficient detail to accurately describe the algorithm. When litigating, look for the §112(f) issue and whether the specification explicitly describes an algorithm or some way to program a computer/processor to perform the recited function.