IP Pipeline Blog

Means-plus-function (“MPF”) is a type of patent claim involved in many important decisions in U.S. patent law. A fundamental patent-law concept – that abstract concepts are not patentable – comes from O’Reilly v. Morse, 56 U.S. 62 (1853), a case involving an MPF claim. The Morse in that case was Samuel Morse and the technology was the telegraph.

MPF allows an inventor to claim a means for doing something without reciting the thing (“structure” in patent terminology) that accomplishes the action. For example, “a means for transporting” could include cars, trucks, boats, airplanes, pack animals, conveyor belts, bike messengers, etc. An MPF claim allows an inventor to avoid enumerating all possible means while covering all “equivalents” of whatever is disclosed in the specification.  Covering equivalents can be important in technology patents where technology is rapidly changing and a specific means may evolve during the life of the patent.

However, MPF claims can be construed narrowly and may be found invalid for indefiniteness if the patent specification does not disclose a “corresponding structure, material, or acts” for “performing the specified function”. 35 U.S.C. § 112(b) and (f). In the example above, if the specification discloses only “a boat” the claim will cover only “a boat” and its equivalents. If the specification does not disclose any “means for transporting” the claim will be found invalid.

MPF claim considered invalid in precedent-setting case due to indefiniteness

The Federal Circuit recently affirmed the invalidity of an MPF claim in Advanced Ground Information Systems, Inc. v. Life360, Inc., Case No. 2015-1732 (Fed. Cir. July 27, 2016)(“Life360”), a case where Eric Christu and I were part of the trial team. Life360 involved patents covering “a cellular communication system that allows multiple cellular phone users to monitor others’ locations and statuses via visual display of such information on a map.” Id. at p. 3.

Life360 is the creator of a smartphone app that “allow[s users] to view family members on a map, communicate with them, and receive alerts”. Id. at p. 5. Advanced Ground Information Systems (“AGIS”) sued Life360 alleging Life360’s smartphone app infringed AGIS’ patents.

The term ‘symbol generator’ is at the center of the Federal Circuit’s precedential decision.  The ‘symbol generator’ displayed information about others on a user’s smartphone screen.  The District Court held that ‘symbol generator’ was a MPF claim that was invalid for indefiniteness.

On appeal, the Federal Circuit found the term ‘symbol generator’ is an MPF claim. Despite not using the words “a means for”, the Court held that “because it fails to describe a sufficient structure and otherwise recites abstract elements ‘for’ causing actions…or elements ‘that can’ perform functions” ‘symbol generator’ is an MPF claim. Life360 at p. 9. The Court found that “the term ‘symbol generator’ is a term coined for the purposes of the patents-in-suit…[it] is not used in ‘common parlance or by persons of skill in the pertinent art…’ such that it connotes sufficient structure…” Id. at p. 10.

Next, the Court found that the patents-in-suit were invalid for indefiniteness because they did “not disclose an operative algorithm for the claim elements reciting ‘symbol generator.’” Life360 at p. 13.  The Court found this was analogous to claiming a means for performing a specific function and subsequently disclosing a general purpose computer as the structure for performing that function. Id. Because, the Court found, the specification did not disclose sufficient structure for the ‘symbol generator’, the patents-in-suit were held invalid. Id.

A word of caution when using MPF claims

Inventors and patentees must exercise caution when using MPF claims. Coining a term or phrase to use in an MPF claim can result in patent invalidity if the specification does not adequately disclose and explain what is meant by the newly-coined term or phrase. If using an MPF claim in a technology or computing patent, make sure structure including, possibly, an algorithm, is recited in the specification; a ‘general purpose computer’ will not be sufficient.