On June 1, 2018, the Federal Circuit vacated and remanded the District Court for the Northern District of California’s decision invalidating Zeroclick’s asserted claims. In a precedential opinion, a Federal Circuit panel held that the district court failed to undertake the relevant inquiry and make factual findings to support its conclusion that Zeroclick’s claims recited means-plus-function terms. The Federal Circuit did not state, with respect to Zeroclick’s claims, that the rebuttable presumption against invoking 35 U.S.C. § 112(f) to interpret a claim limitation not reciting the word “means” could not be overcome. However, the Zeroclick opinion appears to provide the district court with subtle guidance to aid its analysis on remand.
Claim terms that do not recite the word “means” are subject to a rebuttable presumption that § 112(f) does not apply. This presumption protects a patent owner whose claim term does not recite the word “means” against having the claim term interpreted as a narrower means-plus-function term, which is interpreted to cover only the structures, materials, or acts described in the specification and equivalents thereof. If the specification does not provide structural support for a claim term that invokes 112(f), the claim can be found to be invalid under 35 U.S.C. § 112(b).
The presumption may be overcome if a challenger demonstrates, by a preponderance of the evidence, that the claim term “fails to recite sufficiently definite structure or else recites function without reciting sufficient structure for performing that function.” Williamson v. Citrix described the relevant inquiry on this point as “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.” Although Williamson’s articulation of the relevant inquiry replaced the previously “strong” presumption against invoking § 112(f) to interpret a claim term not reciting the word “means,” Zeroclick emphasizes that proper evidentiary support must be marshaled to overcome the rebuttable presumption.
Zeroclick sued Apple for allegedly infringing claims 2 and 52 of U.S. Patent No. 7,818,691 and claim 19 of U.S. Patent No. 8,549,443, the latter of which is a continuation of the former. As noted by the Federal Circuit, Zeroclick’s claims at issue in the ‘691 and ‘443 patents “contemplate updating existing user interface programs by using a two step method” or “by making two configuration changes to the user interface code.” In response, Apple asserted that the claimed limitations, “program that can operate the movement of the pointer (0)” and “user interface code being configured to detect one or more locations touched by a movement of the user’s finger on the screen without requiring the exertion of pressure and determine therefrom a selected operation,” while not reciting the term “means,” should be interpreted as means-plus-function limitations for which the specifications fail to disclose sufficient structure. The district court agreed and construed Zeroclick’s claims under 35 U.S.C. § 112(f), ultimately finding Zeroclick’s asserted claims invalid for indefiniteness under § 112(b).
However, as noted by the Federal Circuit, Apple provided no evidentiary support for its assertion that the claim limitations at issue must be construed under § 112(f). Thus, Apple failed to carry its burden in rebutting the presumption against interpreting Zeroclick’s claims under § 112(f). The district court adopted Apple’s arguments but did not point to evidence of record to support its conclusions. Instead, the district court merely stated (1) “the term ‘program that can operate the movement of the pointer’ is a means-plus-function term because the claim itself fails to recite any structure whatsoever, let alone ‘sufficiently definite structure’” and (2) “because the use of the phrase ‘user interface code’ provides the same ‘black box recitation of structure’ as the use of the word ‘module’ did in Williamson, and the claim language provides no additional clarification regarding the structure of the term, the [c]ourt concludes that ‘user interface code’ constitutes a means-plus-function term.” Because the district court did not support its conclusion with evidence of record, the Federal Circuit concluded, “The [district] court thus legally erred by not giving effect to the unrebutted presumption against the application of § 112, ¶ 6.” The Federal Circuit remanded the matter to the district court for proceedings consistent with the opinion.
When viewed at a high level, the Federal Circuit’s opinion in Zeroclick is a rebuke of the district court’s failure to undertake the relevant inquiry and make related factual findings in it determination that claim limitations not reciting “means” were to be construed under § 112(f). A closer look at Zeroclick also reveals subtle guidance by which the Federal Circuit may have intended to shape the district court’s analysis on remand. The following discussion provides an interpretation of that guidance as well as a word of caution against its broader application.
The Federal Circuit in Zeroclick gave “three related reasons” for its conclusion that the district court erred in treating Zeroclick’s claim terms “‘program’ and ‘user interface code’ as nonce words, which can operate as substitutes for ‘means’ and presumptively bring the disputed claim limitations within the ambit of § 112, ¶ 6.” With respect to the first reason, the Federal Circuit stated, “The mere fact that the disputed limitations incorporate functional language does not automatically convert the words into means for performing such functions.” With respect to the third reason, the Federal Circuit stated, “The district court made no pertinent finding that compels the conclusion that a conventional graphical user interface program or code is used in common parlance as a substitute for ‘means.’” That is, the first and third reasons pertain to the reasoning behind the Federal Circuit’s conclusion that the district court failed, as a matter of procedure, to undertake the relevant inquiry and make related factual findings.
In contrast, the Federal Circuit’s second reason speaks to the substance of the district court’s conclusion. The Federal Circuit noted that “[c]laims 2 and 52 of the ’691 patent . . . recite ‘[a] graphical user interface,’ which their preambles make clear, may comprise ‘an update of an existing program’ using a two-step method . . .. [c]laim 19 of the ’443 patent similarly tethers ‘user interface code’— code meant to be updated using two configuration changes recited in the claim—to the code ‘stored in a memory connected to the processor.’” The Federal Circuit further stated, “Given that ‘[t]he basic concept behind both of the patents-in-suit is relatively simple,’ . . . a person of ordinary skill in the art could reasonably discern from the claim language that the words ‘program,’ as used in claims 2 and 52 of the ’691 patent, and ‘user interface code,’ as used in claim 19 of the ’443 patent, are used not as generic terms or black box recitations of structure or abstractions, but rather as specific references to conventional graphical user interface programs or code, existing in prior art at the time of the inventions.”
As discussed above, the rebuttable presumption that § 112(f) does not apply to a claim limitation not reciting “means” may be overcome if a challenger demonstrates that the claim term “fails to recite sufficiently definite structure or else recites function without reciting sufficient structure for performing that function.” This can be accomplished by showing that “the words of the claim are [not] understood by persons of ordinary skill in the art to have a sufficiently definite meaning as the name for structure.” In emphasizing the existence in the prior art of the claimed “program” and “user interface code,” the Federal Circuit appears to be suggesting that these terms may have definite meaning by virtue of being known to persons of ordinary skill in the art.
However, the Zeroclick opinion does not explicitly make this assertion, and it does not explicitly tie the prior existence of “program” and “user interface code” to the Williamson test. Specifically, the main inquiry of the Williamson test is whether the words of a claim are understood by persons of ordinary skill in the art to have a sufficiently definite meaning as the name for structure. The Zeroclick opinion does not ask or answer the question of whether a person of ordinary skill in the art would understand the terms “program” and “user interface code,” in the context of Zeroclick’s claims or otherwise, to have sufficiently definite meaning as names for structures. Thus, the Federal Circuit’s discussion of the second reason for its conclusion in Zeroclick appears to have been intended to provide limited guidance to the district court on the question of whether a person of ordinary skill in the art would understand Zeroclick’s claim limitations to have definite meaning, thus leaving for the district court the question of whether the claim limitations have definite meaning as names for structures.
At least for these reasons, practitioners are advised to avoid interpreting the Federal Circuit’s statements in Zeroclick as generally disfavoring the interpretation of the terms “program” and “user interface code” under § 112(f). Instead, the safer approach for those wishing to avoid the unwanted interpretation of claims under § 112(f) remains the combined use of claim terms that have been found to connote structure (e.g., “circuit” or “circuitry, where appropriate) and a specification that includes a detailed description of the applicable structure and algorithms so that, even if the claim terms are interpreted to invoke § 112(f), the claims are still definite under § 112(b).
Practitioners hoping to find restriction on the application of § 112(f) amongst Zeroclick’s tea leaves may view this decision as unsatisfying. However, the district court’s decision on remand should indicate whether courts are willing to interpret terms such as “program” and “user interface code” as connoting structure. Most significantly, Zeroclick signaled that while the presumption against the application of § 112(f) to a claim limitation not reciting “means” is no longer strong, the Federal Circuit nevertheless intends to enforce the burden on challengers to conduct the relevant inquiry and produce the necessary factual findings in order to rebut the presumption.
 35 U.S.C. § 112(f) is an America Invents Act (AIA) citation, and 35 U.S.C. § 112, sixth paragraph is the corresponding pre-AIA citation. This article uses 35 U.S.C. § 112(f) to mean 35 U.S.C. § 112(f) or 35 U.S.C. § 112, sixth paragraph.
 Williamson v. Citrix Online, LLC. 792 F.3d 1339, 1348 (Fed. Cir. 2015) (en banc).
 35 U.S.C. § 112(b) is an America Invents Act (AIA) citation, and 35 U.S.C. § 112, second paragraph is the corresponding pre-AIA citation. This article uses 35 U.S.C. § 112(b) to mean 35 U.S.C. § 112(b) or 35 U.S.C. § 112, second paragraph.
 Zeroclick, LLC v. Apple, Inc. No. 2017-126, slip op. at 6 (citing Williamson v. Citrix at 1348).
 Williamson v. Citrix at 1348.