Federal Circuit Holds “User Identification Module” Is A Means-Plus-Function Term And Invalid As Indefinite For Failing To Disclose Corresponding Structure
On March 2, 2021, the Court of Appeals for the Federal Circuit (CAFC) issued an opinion reversing the district court’s conclusion that a claim was not invalid as indefinite. Rain Computing, Inc. v. Samsung Elecs., Am., Inc., __ F.3d __ (Fed. Cir. Mar. 2, 2021). The CAFC held that the claim term, “user identification module,” was a means-plus-function limitation under 35 U.S.C. § 112 ¶ 6, and invalid as indefinite for failure to disclose corresponding structure (here, an algorithm).
Under § 112 ¶ 6, a patentee may draft claims “as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof.” Such claims are construed to cover only “the structure, materials, or acts described in the specification as corresponding to the claimed function and equivalents thereof.” Williamson v. Citrix Online, LLC, 792 F.3d 1339, 1346 (Fed. Cir. 2015) (emphasis added).
To make the determination as to whether a claim term is subject to the means-plus-function strictures of § 112 ¶ 6, the court must determine whether the words of the claim are understood by persons of ordinary skill in the art to have a sufficiently definite meaning as the name for structure. If such words lack a sufficiently definite meaning, then § 112 ¶ 6 applies. Where the claim expressly uses the word “means,” there is a rebuttable presumption that § 112 ¶ 6 applies. On the other hand, where the claim does not use “means” itself, there is a rebuttable presumption that § 112 ¶ 6 does not apply. This latter presumption can be overcome if the patent challenger demonstrates that the claim term fails to recite sufficiently definite structure or else recites function without reciting sufficient structure for performing that function.
The CAFC has held that “nonce” words—such as the term “module” at issue in the instant case—can operate as a substitute for “means.” Here, analogizing to the claim term “distributed learning control module” the CAFC found subject to § 112 ¶ 6 in Williamson, the CAFC found in Rain that the claimed “module” does not provide any indication of structure, and also that Rain failed to point to any claim language providing any structure for performing the claimed function of being configured to control access. Similarly, the prefix “user identification”—just like the “distributed learning control” prefix in Williamson—does not impart structure because it merely describes the function of the module: here, to identify a user. The CAFC further noted that the parties do not dispute that “user identification module” has no commonly understood meaning in the art and is generally not viewed by a person of ordinary skill in the art as imparting structure. And, as to the specification, it also does not impart any structural significance to the term.
After concluding the claim was subject to § 112 ¶ 6, the CAFC then evaluated whether the specification disclosed corresponding structure, or else whether the claim term was indefinite. Under CAFC precedent, for functions performed by a general-purpose computer or processor, the corresponding structure is typically an algorithm that the computer performs to accomplish the claimed function. That is, the structure is not the general-purpose computer, but rather the special purpose computer programmed to perform a corresponding algorithm. (There is a “rare” exception: Where any general-purpose computer without any special programming can perform the function, an algorithm need not be disclosed.) Where programming is necessary and an algorithm is not disclosed, the claim is invalid as indefinite.
Here, the CAFC found that the specification disclosed only a general-purpose computer (computer-readable media and storage devices), but not any corresponding algorithm necessary to actually perform the claimed function. Thus, the claim was indefinite.
Rain is the latest in a long-line of cases holding computer-implemented means-plus-function claim terms indefinite for failing to disclose a corresponding structure (i.e., an algorithm).