Sec. 112(6/f) Claim Language

BASICS: “An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof.” 35 U.S.C. § 112(6/f). Even if raised in the context of an “indefiniteness” Summ. J. motion, “the issue of whether a claim term is governed by § 112 ¶ 6 is a claim construction issue.” Lighting Ballast III (Fed. Cir. 06/23/15) (challenger who lost indefiniteness argument in Markman proceedings did not waive it by not raising it again in JMOL motion or objecting to jury instructions). Congress “struck a balance in allowing patentees to express a claim limitation by reciting a function to be performed rather than by reciting structure for performing that function, while placing specific constraints on how such a limitation is to be construed, namely, by restricting the scope of coverage to only the structure, materials, or acts described in the specification as corresponding to the claimed function and equivalents thereof.” Williamson (Fed. Cir. 06/16/15) (en banc portion); see Dyfan (Fed. Cir. 03/24/22) (rev’g ruling that “code … configured to,” “application … configured to,” and “system … configured to” triggered 112(6/f): “Section 112 ¶ 6 offers patent applicants two options: (1) recite, in the claim, a function without reciting structure for performing the function and limit the claims to the structure, materials, or acts disclosed in the specification (or their equivalents), in which case § 112 ¶ 6 applies, or (2) recite both a function and the structure for performing that function in the claim, in which case § 112 ¶ 6 is inapplicable.”). May not treat a “means-plus-function limitation in [a] patentability analysis as if it were a purely functional limitation.” IPCom (HTC II (IPCom)) (Fed. Cir. 07/07/17) (vacating PTAB reexamination decision for PTAB’s failure to identify algorithm in Spec. corresponding to claim-recited function, after PTAB rejected patent owner’s proposed algorithm). In part, this provides a provisional safe haven from functional-claiming “indefiniteness,” if Spec. satisfies its requirements. But claims invoking this provision often are invalid for not being particular and distinct, for failure of the patent to disclose the required structure. (See “Particular And Distinct Claims (aka Indefiniteness)” (D.8) below.) See Crouch, Patently O (03/02/21) (“Means-plus-function claiming is fools gold — especially for anyone with a thin disclosure. The claims appear broad, but are narrowly interpreted and regularly invalidated.”). See In re Xencor (Fed. Cir. 01/23/24) (non-precedential) (permitting remand at USPTO request “so that the USPTO’s Appeals Review Panel can be convened to ‘clarify the USPTO’s position on the proper analysis of Jepson-format and means-plus function claims in the field of biotechnology, and particularly in the antibody art’”); see Patently O (05/17/24) (discussing USPTO decision on remand: no need for specification to describe “equivalents” to the disclosed structures, materials and acts).
Claim Containing Sec. 112(6/f) Element Lacking Corresponding Structure In Spec. Has No Discernible Meaning And Cannot Be Compared To Prior Art: “Where a claim contains a requirement that must be met by any device or process within its scope, and the meaning of that requirement is entirely unknown, the claim cannot be compared to the prior art for purposes of an invalidity analysis, and so that analysis cannot be conducted…. If the specification fails to recite a corresponding structure [for a sec. 112(6/f) element], then there is a wholly undefined claim element: the claim has what amounts to an inkblot as a required element of the claim. Such a claim logically cannot be compared to prior art, because an essential claim element has no discernible meaning.” Cochlear (Fed. Cir. 05/15/20) (aff’g PTAB refusal to apply prior art to three claims with element triggering sec. 112(6/f) but lacking corresponding structure in Spec., but noting that this has no estoppel effect); cf. Samsung (Fed. Cir. 02/04/20) (the PTAB “may analyze the patentability of a claim even if that claim is indefinite under the reasoning of IPXL” as it may be “invalid for obviousness, regardless of whether it is treated as being directed to an apparatus or a method”). But where claim element covers multiple alternatives, one of which has no discernable scope and renders claim indefinite, but another one has discernible scope, claim may be compared to prior art. Cochlear (Fed. Cir. 05/15/20) (vacating PTAB refusal to apply prior art to claim with element “directivity means comprising at least one directivity dependent microphone and/or signal processing means in the electronic circuitry”). “The indefiniteness of a limitation (here, a means-plus-function limitation) precludes a patentability determination only when the indefiniteness renders it logically impossible for the Board to reach such a decision.” Intel (20-1828) (Fed. Cir. 12/28/21) (vacating PTAB refusal to determine patentability; PTAB must determine for itself whether patent lacks structure corresponding to 112(f) elements and, if so, whether that renders impossible determining patentability).
“A Means For” Performing Two Functions Is More Likely To Be Ambiguous Than “Means For” Performing Two Functions: A claim reciting “‘a means for doing × and y’ … could potentially be ambiguous about whether the limitation required one means for performing both functions × and y, or simply one means for performing function × and one (potentially different) means for performing function y.” Cardiac Pacemakers (Fed. Cir. 07/11/02) (claim recited “means for” not “a means for” and was interpreted as a means with dual functions). See John Bean (Fed. Cir. 09/24/20) (non-precedential) (“‘upper opening means for receiving the poultry carcasses in said tank and for discharging the poultry carcasses from said tank’ does not limit the means performing the first function to also performing the second. Notably, it does not require ‘a means’; it requires only ‘means.’”).

a) whether sec. 112(6/f) treatment invoked

Williamson: “Purely Functional,” “Black Box,” Or “Generic Placeholder” Claim Elements Trigger Sec. 112(6/f); “Definite,” “Particular,” And “Sufficient” Structure In Element Avoids Sec. 112(6/f) Construction: Word “means” creates presumption that Sec. 112(6/f) is invoked and absence of word “means” creates presumption that it is not. But overruling Fed. Cir. case law since 2004, latter, reverse presumption is not “strong.” Rather, “the essential inquiry is not merely the presence or absence of the word ‘means’ but 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” or “or else recites ‘function without reciting sufficient structure for performing that function.’” Williamson (Fed. Cir. 06/16/15) (en banc portion); Synchronoss (Fed. Cir. 02/12/21) (aff’g Summ. J. that “user identifier module” invokes section 112(6/f) and renders claims indefinite: “The standard is whether a person of ordinary skill in the art would understand that the claim terms recite a function but not sufficient structure for performing the function.”); Egenera (Fed. Cir. 08/28/20) (aff’g construction of “logic to modify” as triggering Sec. 112(6/f), “‘logic’ as used in the claims means only a ‘general category of whatever may perform’ the function’”). “We also overrule the strict requirement of ‘a showing that the limitation essentially is devoid of anything that can be construed as structure.’” Williamson (Fed. Cir. 06/16/15) (en banc portion). Coined term that is “simply an abstraction that describes the function being performed” is not sufficient structure to avoid invoking Sec. 112(6/f). Advanced Ground Info. (Fed. Cir. 07/28/16) (“symbol generator” for the generation of symbols). “To determine whether a claim recites sufficient structure, ‘it is sufficient if the claim term is used in common parlance or by persons of skill in the pertinent art to designate structure, even if the term covers a broad class of structures and even if the term identifies the structures by their function.’” Chrimar (Fed. Cir. 05/08/18) (non-precedential) (aff’g terms did not invoke Sec. 112(6/f): “A claim term that has an understood meaning in the art as reciting structure is not a nonce word triggering § 112, ¶ 6.”); Skky (Fed. Cir. 06/07/17) (aff’g PTAB obviousness decision; “wireless device means” does not invoke Sec. 112/6 because “the full term recites structure, not functionality; the claims do not recite a function or functions for the wireless device means to perform, and ‘wireless device’ is ‘used in common parlance . . . to designate structure;’” despite Examiner saying it invoked Sec. 112/6, despite IPR petition asserting the same, and despite word “means” triggering presumption of triggering Sec. 112/6) (quoting TecSec (Fed. Cir. 10/02/13)).
- Post-Williamson; Claims Using “Means”: Masimo (Fed. Cir. 10/24/23) (non-precedential) (aff’g PTAB; “a physiological sensor means . . .” does not trigger 112(6/f) where another claim recites “non-invasive physiological sensor” and not challenged as means-plus-function element); Shperix (Fed. Cir. 07/25/17) (non-precedential) (aff’g PTAB obviousness decision; “processor means at the handset for displaying keyed alphanumeric data on the screen and concurrently transmitting the alphanumeric data and commands to the base station” triggers Sec. 112(6/f)); Skky (Fed. Cir. 06/07/17) (aff’g PTAB “wireless device means” does not invoke Sec. 112/6 because “the full term recites structure, not functionality; the claims do not recite a function or functions for the wireless device means to perform, and ‘wireless device’ is ‘used in common parlance . . . to designate structure’”); Lighting Ballast III (Fed. Cir. 06/23/15) (aff’g district court, based on clear error review of fact finding, judgment that “means” element does not trigger Sec. 112(6/f), based on expert and inventor testimony that PHOSITA “would understand the claimed ‘voltage source means’ to correspond to a rectifier, which converts alternating current (“AC”) to direct current (“DC”), or other structure capable of supplying useable voltage to the device.” “The limitations convey a defined structure to one of ordinary skill in the art.”).
- Post-Williamson; Claims Not Using “Means”—Triggering Sec. 112(6/f): WSOU Investments (Fed. Cir. 10/19/23) (non-precedential) (aff’g that a “processor configured to provide a pre-emptive user output when the sub-set of pixels approaches an edge of the set of available pixels” triggers 112(6/f) because, while some uses of “processor” connote structure, here Spec. “treats the word ‘processor’ so broadly as to generically be any structure that manipulates data [e.g.:] ‘[i]mplementation of the processor 4 can be in hardware alone . . ., have certain aspects in software including firmware alone or can be a combination of hardware and software (including firmware),’”; but rev’g as to another claim element); WSOU Investments (Fed. Cir. 10/06/23) (non-precedential) (aff’g “collaborative application management processor configured to manage collaborative applications” triggers 112(6/f) because “is no categorical rule that ‘processor’ is or is not structural,” the additional language is “purely functional,” “the epitome of functional claiming: a black box that captures any and all structures that fulfill the function,” “there is no indication of how the processor manages collaborative applications,” “claims do not describe how this processor interacts with the other claimed components in a way that might inform the structural character of the limitation,” and Spec. doesn’t use term “processor,” instead referring to “means” for this function); WSOU Investments (Fed. Cir. 09/25/23) (non-precedential) (aff’g “alerting unit configured to issue an alert” triggers 112(6/f) because “unit” “could be almost anything” and the surrounding language in the claims, and Spec., is purely functional, and Spec. uses “means for issuing an alert” as indistinguishable from “alerting unit”); XR Commc’ns (Fed. Cir. 05/18/23) (non-precedential) (aff’g that “search receiver logic … configured to” triggers 112(6/f), despite connoting structure, because challenger showed that term would not connote to POSITA “a sufficiently definite structure” for performing the claim-recited function); Kyocera (Fed. Cir. 01/21/22) (rev’g ITC construction and remanding for determination of corresponding structure; “a lifter member which exhibits a contact surface that, at predetermined locations along said contact surface, makes contact with said plurality of spaced-apart protrusions of said driver member such that, when said lifter member is moved in a first direction, it causes a return stroke of an operating cycle and moves said driver member from a driven position toward a ready position, and when said lifter member is moved to a holding position, it temporarily holds said driver member at said ready position by use of a holding contact between said lifter member and said driver member” invokes 112(6/f) because (1) “lifter member” is “a non-structural generic placeholder (member) modified by functional language (lifter),” (2) “the only thing a skilled artisan could glean from the claim language is that the lifter member is moved by the prime mover and lifts the driver member. That is a purely functional description,” (3) term has no plain meaning in the art, and (4) while Spec. gives examples of “lifter member” it does not give “a clear and unambiguous definition” thereof); Team Worldwide (Fed. Cir. 09/09/21) (non-precedential) (aff’g PTAB that “pressure controlling assembly” “configured to” perform four functions, invokes section 112(f) (based on functional claim format, “assembly” being generic term, Spec. not providing the term a structural definition, and extrinsic evidence showing that term is defined in functional terms, and giving no weight to Examiner’s silence on whether claim term invokes section 112(f)), and renders claims indefinite); Rain Computing (Fed. Cir. 03/02/21) (aff’g “user identification module configured to control access of …” nested in method claim triggers Sec. 112(6/f) as “module” is nonce term, “user identification” describes function, “the purely functional claim language reciting what the ‘user identification module’ is configured to do provides no structure,” the claim term is not a term of art for structure, and term not used in Spec.; rejecting argument that amendment made during prosecution of “a user identification module for accessing . . .” to “a user identification module configured to control access of . . .” prevents “user identification module” from being a means-plus-function term); Synchronoss (Fed. Cir. 02/12/21) (aff’g, without much analysis, Summ. J. “user identifier module” in apparatus claim triggers Sec. 112(6/f)); Egenera (Fed. Cir. 08/28/20) (aff’g construction of “logic to modify” in “platform” claim as triggering Sec. 112(6/f), “Egenera does not explain how its ‘logic’—even assuming it connotes some possible structure in the general sense of software, firmware, or circuitry [as argued by the patentee]—amounts to ‘sufficient structure for performing [the modification] function.’”); Dionex (Fed. Cir. 05/06/20) (non-precedential) (in interference, aff’g method claim step in issued patent (“controlling the valve to switch among predetermined valve positions to transfer the sample loop between a low pressure and a high pressure”) triggers Sec. 112(6/f) (and is indefinite) based on expert testimony “that the claim term would not connote acts to a person of skill sufficient to perform the recited function”); Intelligent Automation (Fed. Cir. 01/30/20) (non-precedential) (aff’g that “determining a time when torque reaches a maximum” triggers Sec. 112(6/f) in method claim (which neither party disputed), and that “a control circuit for determining a time when torque reaches a maximum” in system claim also triggers Sec. 112(6/f), because “control circuit” does not “provide enough description of the structure to render the limitation structural, rather than functional”); Fiber (Fed. Cir. 11/21/19) (non-precedential) (aff’g district court that “control” in system claim invokes Sec. 112(6/f) in part because control depicted in figure was a “generic box with no indication of any structure”); Grecia (Fed. Cir. 08/20/19) (non-precedential) (aff’g district court finding that “customization module” in product claim invokes Sec. 112(6/f), in part because nothing in claim recites “how [it] operates,” and finding of indefiniteness); MTD Products (Fed. Cir. 08/12/19) (vacating PTAB obviousness decision; contrary to PTAB; “a mechanical control assembly … configured to …” triggers Sec. 112(6/f), as patent owner argues; in part because similar to other nonce terms, “configured to” format defines functions, and term used in prior art to describe “a wide variety of structures with varying functions,” despite Spec. describing a corresponding structural embodiment); Diebold Nixdorf (Fed. Cir. 08/15/18) (rev’g ITC; term “cheque standby unit” is a means-plus-function term, and, lacking structural support, indefinite; “claims describe the term ‘cheque standby unit’ solely in relation to its function and location in the apparatus;” Spec. describes no specific structure; figure depicts unit as a vertical line; patent owner’s expert “offered purely functional definitions” and in effect testified it meant “any structure capable of performing the claimed function;” and there was no evidence “in the form of dictionary definitions or otherwise—that ‘cheque standby unit’ was reasonably well understood by persons of ordinary skill in the art to refer to a structure or class of structures.”); Advanced Ground Info. (Fed. Cir. 07/28/16) (aff’g indefiniteness; “‘symbol generator [e.g., “a symbol generator connected to [a] CPU and [a] database for generating symbols on [a] touch screen display screen”] invokes the application of § 112, ¶ 6 because it fails to describe a sufficient structure and otherwise recites abstract elements ‘for’ causing actions, or elements ‘that can’ perform functions,” even though terms “symbol” and “generator” were known in the field); Media Rights (Fed. Cir. 09/04/15) (“compliance mechanism” triggers Sec. 112(6/f): not commonly known in art as name for a particular structure and Spec. describes it only by its functions, connections and optional “functional components,” not in specific structural terms); Williamson (Fed. Cir. 06/16/15) (panel portion) (aff’g “indefiniteness”; claim element does trigger Sec. 112(6/f): “a distributed learning control module for receiving communications transmitted between the presenter and the audience member computer systems and for relaying the communications to an intended receiving computer system and for coordinating the operation of the streaming data module,” because uses format of “means” element and replaces “means” with “nonce word” “module” which, like “means,” is a “generic,” “black box” “description for software or hardware that performs a specified function,” and the written description’s description of the element “fails to impart any structural significance” to the term”)).
- Post-Williamson; Claims Not Using “Means”—Not Triggering Sec. 112(6/f): WSOU Investments (Fed. Cir. 10/19/23) (non-precedential) (rev’g that “at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to” triggers 112(6/f), in part because “the recited combination of these multiple broadly named structures informs the skilled artisan’s relative understanding of what each structure is and what it is not, as well as how the various structures relate to one another, but aff’g as to another element); VDPP (Fed. Cir. 03/25/22) (non-precedential) (rev’g indefiniteness; party urging 112(6/f) triggered by “processor … adapted to” and “storage … adapted to” presented no evidence to overcome the presumption, and Spec. indicated that processors and storage were well known to skilled artisans), petition for rehearing en banc (05/02/22); Dyfan (Fed. Cir. 03/24/22) (rev’g indefiniteness; the limitations (“system comprising … code, when executed, further configured to after the first visual information is caused to be output based on the first location-relevant information; after the at least one mobile device is moved in the building; and in response to the receipt, from the at least one server and via the second wireless communications protocol, of the second response message including the second location-relevant information: cause to be output, via the at least one mobile device, the second visual information based on the second location-relevant information.…,” “application [configured to …], and “system [configured to …]”) do not trigger 112(6/f) where “system” referred back to the “code” as performing the function and challenger’s own expert testified that skilled artisans would have understood that “conventional” “off-the-shelf” applications and code were available to perform the functions), petition for rehearing en banc (05/02/22) (treating “code” as structure is contrary to Williamson) [Professors’ Amici in support of rehearing (05/16/22) (“If software patentees can avoid Williamson and write purely functional claims merely by using the word ‘code’ in place of actual structure, this Court will have rendered Williamson a dead letter”)]; Samsung (Fed. Cir. 02/04/20) (rev’g PTAB ruling; “digital processing unit” does not invoke Sec. 112(6/f), “the term ‘digital processing unit’ clearly serves as a stand-in for a ‘general purpose computer’ or a ‘central processing unit,’ each of which would be understood as a reference to structure in this case, not simply any device that can perform a particular function”); Tek Global (Fed. Cir. 03/29/19) (aff’g “conduits connecting the container” does not trigger Sec. 112(6/f) in part because applicant said so in prosecution and also in view of claims and Spec.; “although connoting precise physical structure is not a necessary condition to avoid § 112, ¶ 6 application, it is generally sufficient.”); Zeroclick (Fed. Cir. 06/01/18) (rev’g holding that following trigger Sec. 112(6/f): “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.” Skilled artisan “could reasonably discern from the claim language that the words [“program” and “user interface code” as used in the claims] 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.”); Chrimar (Fed. Cir. 05/08/18) (non-precedential) (aff’g terms (“central piece of equipment,” “Ethernet terminal equipment,” and “BaseT Ethernet terminal equipment” followed by “to detect,” “to control,” “to provide,” “to distinguish,” “to draw,” “to result,” and “to convey”), did not invoke Sec. 112(6/f)).
- Now-Overruled Case Law On Triggering Sec. 112(6/f): There is a “strong” “presumption” that a claim term other than “means” does not invoke Sec. 112(6/f). Lighting World (Fed. Cir. 09/03/04); Robert Bosch (Fed. Cir. 10/14/14) (presumption overcome for “program recognition device” and “program loading device” because “device” is non-structural nonce word and other terms in phrase are purely functional and neither Spec. nor dependent claims defined or described in structural terms). When “means” is not used, test is whether the claim term is used in the pertinent art “to designate structure, even if the term covers a broad class of structures and even if the term identifies the structures by their function.” Mass. Inst. of Tech. & Elecs. for Imaging (Fed. Cir. 09/13/06); Williamson (Fed. Cir. 11/05/14) (2-1) (“a distributed learning control module for…” not Sec. 112(6/f): “module” has dictionary meanings connoting hardware or software structure in the computer arts; context in claims and Spec. suggest structure), vacated, Williamson (Fed. Cir. en banc order 06/16/15), Williamson (Fed. Cir. 06/16/15) (panel portion) (different result: language does trigger Sec. 112(6/f) and claim is indefinite); EnOcean (Fed. Cir. 01/31/14) (“signal receiver for receiving” does not trigger Sec. 112/6, as term “receiver” is understood in the art; rev’g BPAI); Power Integrations (Fed. Cir. 03/26/13) (“soft start circuit,” with recited input, output and straightforward function, connotes “sufficiently definite structure”). But see Apple (Fed. Cir. 04/25/14) (2-1) (claim term “heuristics,” construed in light of Spec., provides sufficient structure; when “means” is not used: to determine whether claim is in means-plus-function format “we must construe the claim limitation to decide if it connotes ‘sufficiently definite structure’ to a person of ordinary skill in the art, which requires us to consider the specification (among other evidence).”) [distinguished in Grecia (Fed. Cir. 08/20/19) (non-precedential) noting that Apple was decided under “strong presumption” rule].
- Overruled 2014 Williamson Panel Opinion: “The district court, in characterizing the word ‘module’ as a mere nonce word, failed to appreciate that the word ‘module’ has understood dictionary meanings as connoting either hardware or software structure to those skilled in the computer arts. …. The IBM Corporation, IBM Dictionary of Computing 439 (1st ed.1994) defines ‘module’ as a ‘packaged functional hardware unit designed for use with other components’ and a ‘part of a program that usually performs a particular function of related functions.’ See also … (defining ‘module’ as a ‘self-contained hardware or software component that interfaces with a larger system’); … (defining ‘module’ as a ‘programming or specification construct that defines a software component’ and a ‘component of a hardware system that can be subdivided’). These definitions all show that the term ‘module’ has a structure connoting meaning to persons of ordinary skill in the computer arts…. Here, the ‘distributed learning control module’ is claimed as a part of the definite structure ‘distributed learning server’ and ‘receive[s] communications transmitted between the presenter and the audience member computer systems,’ ‘relay[s] the communications to an intended receiving computing system,’ and ‘coordinat[es] the operation of the streaming data module.’ These claimed interconnections and intercommunications support the conclusion that one of ordinary skill in the art would understand the expression ‘distributed learning control module’ to connote structure…. The specification also makes clear that the distributed learning control module includes software that runs on a portion of the distributed learning server. While the supporting specification describes the claimed expression ‘distributed learning control module’ in a high degree of generality, in some respects using functional expressions, it is difficult to conclude that it is devoid of structure.” Williamson (Fed. Cir. 11/05/14) (2-1) (“a distributed learning control module for…” does not trigger Sec. 112(6/f)), vacated, Williamson (Fed. Cir. en banc order 06/16/15), Williamson (Fed. Cir. 06/16/15) (panel portion) (different result: language does trigger Sec. 112(6/f) and claim is indefinite).
For A Claim Element To Trigger Sec. 112(6/f), Claim Must Recite Function That The Element Performs Without Sufficient Structure: Skky (Fed. Cir. 06/07/17) (aff’g PTAB obviousness decision; “wireless device means” does not invoke Sec. 112/6 because “the full term recites structure, not functionality; the claims do not recite a function or functions for the wireless device means to perform, and ‘wireless device’ is ‘used in common parlance . . . to designate structure’”); Cochlear (Fed. Cir. 05/15/20) (vacating Board finding of insufficient structure for means-plus-function limitation and remanding for determination of whether “directivity means” was a means-plus-function limitation in light of further limitation reciting potentially sufficient structure (“directivity dependent microphone”)).
Reciting Or Implying That Function Is Computer Or Processor Implemented Is Not Enough To Connote Definite Structure: Each of Williamson (Fed. Cir. 06/16/15) (functions require “a special purpose computer”), Media Rights (Fed. Cir. 09/04/15) (“these functions are computer-implemented functions”), and Advanced Ground Info. (Fed. Cir. 07/28/16), involved claims reciting computer or processor implemented software functions yet were deemed to trigger Sec. 112(6/f) construction.
The “Structure” May Be A Program Or Program Code: “In determining whether software limitations … recite sufficient structure, we can look beyond the initial ‘code’ or ‘application’ term to the functional language to see if a person of ordinary skill would have understood the claim limitation as a whole to connote sufficiently definite structure.” Dyfan (Fed. Cir. 03/24/22) (rev’g indefiniteness; the limitations (“system comprising … code, when executed, further configured to after the first visual information is caused to be output based on the first location-relevant information; after the at least one mobile device is moved in the building; and in response to the receipt, from the at least one server and via the second wireless communications protocol, of the second response message including the second location-relevant information: cause to be output, via the at least one mobile device, the second visual information based on the second location-relevant information.…,” and “application [configured to ….]”) where challenger’s own expert testified that skilled artisans would have understood that “code” is “a bunch of software instructions” and “conventional” “off-the-shelf” applications and code were available to display whatever information the developer chooses, which “demonstrates that the “code”/“application” limitations here connote a class of structures to a person of ordinary skill.”); Zeroclick (Fed. Cir. 06/01/18) (rev’g holding that following trigger Sec. 112(6/f): “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.” Skilled artisan “could reasonably discern from the claim language that the words [“program” and “user interface code” as used in the claims] 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.”).
- Note: Information is not structure, materials, or acts. These decisions do not address why information (e.g., code instructions, as distinct from a processor configured per code instructions) qualify as structure. Per USPTO Legal Training Module guidance (08/02/13): “Terms that represent only non-structural elements such as information, data, instructions, and software per se would not serve as substitutes for “means”, because the terms do not serve as placeholders for structure or material.”
Reciting Location Relative To, Connections To, Or Interactions With Other Elements May Not Be Sufficient To Recite Or Connote Definite Structure: Each of Williamson (Fed. Cir. 06/16/15) (“distributed learning control module” element received communications from one element and relayed them to another), Media Rights (Fed. Cir. 09/04/15) (“compliance mechanism” was “coupled to” three other elements in the claim; “Nothing in the written description … adds sufficiently to the meaning of the term’s structure; it only describes the term’s function and interaction with other parts in the system.”), and Advanced Ground Info. (Fed. Cir. 07/28/16) (“a symbol generator connected to said CPU and said database for generating symbols on said touch display screen;” “symbol generator in said CPU that can generate symbols….”), involved claim elements recited in claims and/or Spec. as being connected to, part of, or interacting with, other claim elements, but those recitations did not sufficient to recite or connote the required definite structure. Accord Diebold Nixdorf (Fed. Cir. 08/15/18) (rev’g ITC; claims recited and Spec. described location of “cheque standby unit” relative to other elements, and its functions, but not its specific structure, and thus triggered Sec. 112(6/f) construction); Egenera (Fed. Cir. 08/28/20) (even if claim language defined the “inputs, outputs, connections, and operation” of the logic component, those elements in view of the Spec. did not define sufficient structure of the “logic to modify”).
That Limitation Is Inside A Structure Does Not Mean It Is Sufficiently Structural: “Mere inclusion of a limitation within a structure does not automatically render the limitation itself sufficiently structural.” Egenera (Fed. Cir. 08/28/20) (aff’g construction of “logic to modify” as triggering Sec. 112(6/f), despite it being inside a “control node”).
Spec. Disclosing Structural Embodiment Corresponding To Claim Element Does Not Mean Claim Element Connotes Structure Or Avoids Invoking Sec. 112(6/f): “That the specification discloses a structure corresponding to an asserted means-plus-function claim term does not necessarily mean that the claim term is understood by persons of ordinary skill in the art to connote a specific structure or a class of structures.” MTD Products (Fed. Cir. 08/12/19) (vacating PTAB obviousness decision; Spec. “does not demonstrate that the patentee intended to act as its own lexicographer and define the nonce term “mechanical control assembly” as the “ZTR control assembly” of the preferred embodiment”).
Preponderance Burden Of Production To Overcome Presumptions For Or Against Triggering Of Sec. 112(6/f): Burden of production to overcome rebuttable presumption created by use or non-use of “means” “must be met by a preponderance of the evidence.” Apex (Fed. Cir. 04/02/03); Dyfan (Fed. Cir. 03/24/22) (where claim element does not use means, party urging 112(6/f) invoked must provide at least some evidence that a skilled artisan would not have understood the limitation to “recite sufficiently definite structure[s]”); Zeroclick (Fed. Cir. 06/01/18) (rev’g holding that following trigger Sec. 112(6/f): “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” because challenger provided no intrinsic or extrinsic evidence to overcome presumption.); Advanced Ground Info. (Fed. Cir. 07/28/16) (aff’g indefiniteness; where claim does not use “means,” “the challenger must establish by a preponderance of the evidence that the claims are to be governed by § 112, ¶ 6”); VDPP (Fed. Cir. 03/25/22) (non-precedential) (rev’g indefiniteness; party urging 112(6/f) triggered by “processor … adapted to” and “storage … adapted to” presented no evidence to overcome the presumption, and Spec. indicated that processors and storage were well known to skilled artisans).
No Expert Testimony Or Other Extrinsic Evidence Is Necessary To Overcome Presumption: No extrinsic evidence necessary to overcome presumption created by absence of “means” term in claim element. WSOU Investments (Fed. Cir. 10/06/23) (non-precedential) (aff’g “collaborative application management processor configured to manage collaborative applications” triggers 112(6/f)).
(Pre-Williamson) Rebutting Sec. 112(6/f) Presumption Created By “Means”: Use of “means” triggers rebuttable presumption that Sec. 112(6/f) is invoked. “Sufficient structure exists [to rebut that presumption] when the claim language specifies the exact structure that performs the functions in question without need to resort to other portions of the specification or extrinsic evidence for an adequate understanding of the structure.” TriMed (Fed. Cir. 01/29/08); but see Inventio AG (Fed. Cir. 06/15/11) (the claim “must ‘specif[y] the exact structure that performs the functions in question,’” but noting that “where the claims recite the term ‘means,’ we have considered the written description to inform the analysis of whether the claim recites sufficiently definite structure to overcome the presumption.”) (citation omitted). See Chicago Bd. (Fed. Cir. 05/07/12) (“system memory means” is means-plus-function element (dictum); corresponding structure is “system memory.”); TecSec (Fed. Cir. 10/02/13) (“system memory means” for storing data, and “digital memory means,” do not invoke Sec. 112, ¶ 6, the latter in part because claim recites no function [but citing case law (Lighting World) on different issue (whether term other than “means” invokes Sec. 112/6))]); Lighting Ballast I (Fed. Cir. 01/02/13) (Sec. 112/6 element: “voltage source means providing a constant or variable magnitude DC voltage between the DC input terminals,” rejecting expert testimony for failure to show “voltage source” was “used synonymously with a defined class of structures at the time the invention was made”) (non-precedential), vacated en banc (Fed. Cir. 03/15/13) (to revisit Cybor), reinstated (Fed. Cir. 02/21/14), vacated ivo Teva (U.S. 01/26/2015), on remand Lighting Ballast III (Fed. Cir. 06/23/15) aff’g trial court’s claim construction that claim term did not trigger Sec. 112(6/f) and claim is not indefinite).
(Pre-Williamson) When Sec. 112(6/f) Triggered Without Using Word “Means”: There is a “strong presumption” that a claim term other than “means” does not invoke Sec. 112(6/f). Inventio AG (Fed. Cir. 06/15/11) (“modernizing device” and “computing unit” in these claims do not trigger Sec. 112(6/f)) (distinguished in Robert Bosch (Fed. Cir. 10/14/14)). A claim term does not trigger Sec. 112(6/f), if it suggests structure, even if not a specific structure. See Lighting World (Fed. Cir. 09/03/04) (“Thus, while it is true that the term ‘connector assembly’ does not bring to mind a particular structure, that point is not dispositive. What is important is whether the term is one that is understood to describe structure, as opposed to a term that is simply a nonce word or a verbal construct that is not recognized as the name of structure and is simply a substitute for the term ‘means for.’”); Mass. Inst. of Tech. & Elecs. for Imaging (Fed. Cir. 09/13/06) (“it is sufficient if the claim term is used in common parlance or by persons of skill in the pertinent art to designate structure, even if the term covers a broad class of structures and even if the term identifies the structures by their function”); Baran (Fed. Cir. 08/12/10) (“The relevant inquiry is whether the [claim] term at issue is purely functional.”). In determining whether claim term suggests structure, court should look to intrinsic and perhaps extrinsic evidence same as any other construction. Inventio AG (Fed. Cir. 06/15/11); Powell (Fed. Cir. 11/14/11) (“dust collection structure” is not Sec. 112(6/f) element: “the written description identifies several prior art patents that disclose various types of dust collection structures”); Flo Healthcare (Fed. Cir. 10/23/12) (“a height adjustment mechanism for altering the height of the horizontal tray” does not invoke Sec. 112(6/f): “the noun “adjustment,” … has a reasonably well-understood meaning as a name for a structure”); Mas-Hamilton (Fed. Cir. 09/10/98) (“lever moving element” and “movable link member” trigger Sec. 112(6/f)).
Method Claims May Include “Means Plus Function” Elements, And Reciting Step Taken By An Apparatus May Imply Function Of That Apparatus: Method claims may recite elements triggering Sec. 112(6/f) treatment, and reciting steps taken by an apparatus may be treated as reciting functions that apparatus can perform. E.g., Media Rights (Fed. Cir. 09/04/15) (aff’g judgment of indefiniteness on the pleadings (filed and argued during Markman proceedings); “compliance mechanism” in method claim’s step “controlling a data output pathway of said client system with said compliance mechanism by diverting a commonly used data pathway of said media player application to a controlled data pathway monitored by said compliance mechanism” triggers Sec. 112(6/f), in part because “the claims simply state that the ‘compliance mechanism’ can perform various functions.”); Saffran (Fed. Cir. 04/04/13) (both method and device claims recited a “release means for ….”).
“Step Plus Function” Element: “The word ‘means’ clearly refers to the generic description of an apparatus element, and the implementation of such a concept is obviously by structure or material. We interpret the term ‘steps’ to refer to the generic description of elements of a process, and the term ‘acts’ to refer to the implementation of such steps.” “The paragraph is implicated only when steps plus function without acts are present.” Overall result of method is not same as function of an individual step: “Performing a series of steps inherently produces a result, in this case the removal of water vapor from the analyte slug, but a statement in a preamble of a result that necessarily follows from performing a series of steps does not convert each of those steps into step-plus-function clauses.” O.I. Corp. v. Tekmar Co., 115 F.3d 1576, 1582-83 (Fed. Cir. 1997) (despite parallelism with apparatus claims, following step is not in step plus function format: “‘the step[s] of … passing the analyte slug through a passage’” because the step of “passing” is “not individually associated in the claim with functions performed by the” step). Absence of “step for” language creates presumption that method step does not trigger Sec. 112(6/f). Generation II (Fed. Cir. 08/15/01). Use of “step for” triggers presumption of Sec. 112(f/6) treatment, and even then, claim must not recite acts in support of that step. Masco (Fed. Cir. 08/28/02) (rev’g trial court’s treatment of claim step) (“transmitting a force applied to the knob to the lever through the rigid connection after the lever and the knob have been operably connected to drive the lever to a position where the protrusion can contact the surface of the cam wheel in such a manner that the lever will be pulled by the cam wheel during rotation of the cam wheel”) as Sec. 112(f/6) step, because “‘Transmitting a force’ describes how the lever is driven into the cam. In other words, ‘transmitting’ in the sense of causing a force to be conveyed through a medium by mechanical parts is an act, since it describes how the function of the “transmitting a force” limitation is accomplished.” Citing Judge Rader’s concurrence in Seal-Flex.). “Where a method claim does not contain the term ‘step[s] for,’ a limitation of that claim cannot be construed as a step-plus-function limitation without a showing that the limitation contains no act.” Id. “In general terms, the ‘underlying function’ of a method claim element corresponds to what that element ultimately accomplishes in relationship to what the other elements of the claim and the claim as a whole accomplish. ‘Acts,’ on the other hand, correspond to how the function is accomplished. …. If a claim element recites only an underlying function without acts for performing it, then § 112, ¶ 6 applies even without express step-plus-function language. …. If the language of the claim element does not expressly state its function, the function of that element may nonetheless be discernible from the context of the overall claim and the disclosure in the specification. …. [I]f this claim limitation (“spreading an adhesive tack coating for adhering the mat to the foundation over the foundation surface”) had specified only the underlying function, namely, ‘adhering the mat to the foundation,’ without recital of specific acts for ‘adhering,’ § 112, ¶ 6 would have governed, despite the lack of ‘step for’ language.” Seal-Flex (Fed. Cir. 04/01/99) (Rader, J. concurring); Dionex (Fed. Cir. 05/06/20) (non-precedential) (in interference, aff’g method claim step in issued patent (“controlling the valve to switch among predetermined valve positions to transfer the sample loop between a low pressure and a high pressure”) triggers Sec. 112(6/f) (and is indefinite) based on expert testimony “that the claim term would not connote acts to a person of skill sufficient to perform the recited function”); Epcon Gas (Fed. Cir. 02/01/02) (rev’g application of Sec. 112(6/f) to method step: “The claim includes no words indicating ‘step plus function’ form, such as ‘step for.’ [citing Judge Rader concurrence in Seal-Flex]. The claim recites a series of steps without the recital of function.”); Intelligent Automation (Fed. Cir. 01/30/20) (non-precedential) (aff’g that “determining a time when torque reaches a maximum” triggers Sec. 112(6/f) in method claim (which neither party disputed), and that “a control circuit for determining a time when torque reaches a maximum” in system claim also triggers Sec. 112(6/f)). See Serrano (Fed. Cir. 04/25/97) (“automatically determining at least the last-dialed number of the telephone number dialed on the telephone communications-type device” does not trigger 112(6/f) because it recites an act not a function). Cf. Alice Corp. (U.S. 06/19/2014) (claim elements “data processing system,” “communications controller,” and “data storage unit,” are “purely functional and generic.”); Lemley, Software Patents and the Return of Functional Claiming (Wisc. Law Review 10/12/12) (“The intent of this statute was to allow functional claiming only when it was limited to particular implementations of that function, not when it encompassed all feasible ways of achieving the goal.”). See Logan, “Step-Plus-Function Claims: An Analysis of Federal Circuit Law” (2014). But see USPTO Memorandum (“Resources for Examining Means-Plus-Function and Step-Plus-Function Claim Limitations (35 U.S.C. 112(f))”) (03/18/2024) (“A step limitation must not recite an act to be treated under § 112(f), but most process claims include steps with acts described by a verb ending in “-ing” (such as passing, heating, reacting, transferring, determining, etc.), which will avoid § 112(f).”).
TIPS:

b) construction of sec. 112(6/f) claim element

Corresponding Structure Must Be Clearly Linked In Spec. To The Claim-Recited Function Not Merely Capable Of Performing The Function: Spec. must disclose the structure and clearly link it to the claimed function. Medtronic (Fed. Cir. 04/20/01) (structure must be clearly linked to claimed function, e.g., in Spec., dependent claims, or prosecution history, not merely capable of performing the function); B. Braun Medical (Fed. Cir. 09/08/97) (“structure disclosed in the specification is ‘corresponding’ structure only if the specification or prosecution history clearly links or associates that structure to the function recited in the claim. This duty to link or associate structure to function is the quid pro quo for the convenience of employing § 112, ¶ 6.”); MobileMedia (Fed. Cir. 03/17/15) (rev’g infringement judgment based on too-broad interpretation of corresponding structure). Cloud Farm (Fed. Cir. 01/09/17) (non-precedential) (aff’g indefiniteness for lack of corresponding structure in Spec.); Telcordia (Fed. Cir. 07/06/10) (linking disclosure sufficient in view of supporting expert testimony and presumption of validity).
Corresponding Structure Is Only That Portion Of Disclosed Structure Necessary To The Claimed Function(s): The corresponding structure is only that part of the disclosed structure necessary to performing that claimed function. John Mezzalingua Assocs. (Fed. Cir. 04/28/11) (non-precedential); Northrop (Fed. Cir. 03/31/03) (“A court may not import into the claim features that are unnecessary to perform the claimed function. Features that do not perform the recited function do not constitute corresponding structure and thus do not serve as claim limitations.”); Univ. of Pitt. (Fed. Cir. 04/10/14) (corresponding algorithm is only what is necessary to perform the function, here two-step algorithm described in the background (“(1) identifying at least one fiducial from the image signals, and (2) tracking the movement of the fiducial(s), and equivalents,” not more detailed optional implementations later in Spec.). Cf. Egenera (Fed. Cir. 08/28/20) (three components “function in concert to” perform the claimed functions).
Corresponding Structure Must Perform All Of The Element’s Claim-Recited Functions: “Where there are multiple claimed functions, as we have here, the patentee must disclose adequate corresponding structure to perform all of the claimed functions.” Williamson (Fed. Cir. 06/16/15).
“Structure” Need Not Be Physical And May Be An Algorithm: “The ‘structure’ of computer software is understood through, for example, an outline of an algorithm, a flowchart, or a specific set of instructions or rules.” Apple (Fed. Cir. 04/25/14) (2-1) (in context of overcoming presumption that claim element “heuristics” is not a means-plus-function element); Business Objects (Fed. Cir. 01/06/05) (corresponding structure may be an algorithm). See Apple V (Fed. Cir. 02/26/16) (in part because hardware “alone, does nothing without software instructions telling it what to do,” the district court correctly included software as part of the corresponding structure for “means for transmission.”), reinstated Apple VI (Fed. Cir. 10/07/16) (en banc) (7-3); Sony (Fed. Cir. 05/22/19) (2-1) (identifying algorithm as flowchart in patent and corresponding narrative description thereof).
If Function Is Implemented By Computer Or Other Programmed Machine Rather Than A Circuit Or Other Hardware, The Corresponding “Structure” Must Include An Algorithm, Not Just Functions Or Results: Sony (Fed. Cir. 05/22/19) (vacating PTAB obviousness decision and rev’g construction that omitted algorithm; “reproducing means for reproducing the audio data …” is construed as computer implemented despite a hardware (circuit) embodiment also being disclosed, because Spec. refers to “the processing” of the “controller” part of the reproduction device as shown in a flowchart, and does not “describe or refer to the circuitry of the controller that would be required for a hardware controller to perform the claimed function”); Impact Engine (Fed. Cir. 07/03/24) (2-1) (non-precedential) (aff’g non-infringement vis-à-vis Section 112(6/f) element where infringement theory depended entirely on Spec. passage that provided nothing “substantial beyond what is required by the construction of the claimed rendering function”); WSOU Investments (Fed. Cir. 09/25/23) (non-precedential) (aff’g that Spec. did not clearly link structure as opposed to functions to the claim-recited function); Uniloc (Fed. Cir. 04/07/20) (non-precedential) (aff’g indefiniteness for lack of corresponding structure; “for a computer-implemented invention claimed in means-plus-function format, the specification must disclose the algorithm that the computer performs to accomplish the claimed function,” not merely the function or result itself).
Corresponding Structure Encompasses Each Embodiment Disclosed And Linked In Spec., Even If Only Briefly Mentioned: Sec. 112(6/f) element embraces each embodiment corresponding to the claimed function, even if an embodiment is only briefly mentioned. Versa (Fed. Cir. 12/14/04) (a one sentence mention of an alternative embodiment is enough to make that an alternative structural counterpart to a means plus function element); Micro Chemical (Fed. Cir. 10/06/99) (“When multiple embodiments in the specification correspond to the claimed function, proper application of § 112, ¶ 6 generally reads the claim element to embrace each of those embodiments.”). But does not include structures disclosed not in the Spec. but rather only in prior art listed in the patent Spec. Pressure Prod. (Fed. Cir. 03/24/10). Unsettled: these cases do not address whether the alternative “embodiment” must otherwise comply with the claim.
Spec. Must Identify The Corresponding Structure, Not Merely Reference It Generically Or State That Known Or Conventional Ways May Be Used: “A bare statement that known techniques or methods can be used does not disclose structure.” Biomedino (Fed. Cir. 06/18/07); see Twin Peaks (Fed. Cir. 05/26/17) (non-precedential) (aff’g indefiniteness; distinguishing enablement from requirement of specifying the corresponding structure: “by engaging in functional claiming under § 112 ¶ 6, a patentee is entering into the bargain of limiting its open-ended functional claim term to what is disclosed and their equivalents, which may not be coextensive with the full enabled scope”); Triton Tech (Fed. Cir. 06/13/14) (Spec. stated that the claim-recited numerical integration function is performed in a “conventional manner”); Saffran (Fed. Cir. 04/04/13) (corresponding structure limited to “hydrolyzable bonds,” not more generic “chemical bonds and linkages.”) (2-1) (rev’g judgment of infringement); Default Proof (Fed. Cir. 06/16/05) (“This duty to link or associate structure to function is the quid pro quo for the convenience of employing § 112, ¶ 6.”); Med. Instrumentation (Fed. Cir. 09/22/03) (that PHOSITA would know of structure which could perform the function is insufficient, the Spec. must disclose the structure); Mettler-Toledo (Fed. Cir. 02/08/12) (where patent discloses a single embodiment (multiple slope integrating A/D converter), the corresponding structure is limited to that embodiment even if generic devices were known in the art for performing such function and there is a reference in abstract to such a generic device (A/D converter), as that reference was not linked to the claimed function) (aff’g Summ. J. of non-infringement); Bennett Marine (Fed. Cir. 09/19/13) (non-precedential) (only one embodiment disclosed even though shown more generically in one figure).
Corresponding Structure Perhaps Cannot Be Incorporated By Reference At All, And Likely Cannot Be Incorporated By Reference To Something Other Than A Published U.S. Patent Or Patent Application: “Material incorporated by reference cannot provide the corresponding structure necessary to satisfy the definiteness requirement for a means-plus-function clause.” Default Proof (Fed. Cir. 06/16/05) (citing Atmel); Atmel (Fed. Cir. 12/28/99) (2-1) (title of non-patent publication sought to be incorporated sufficient to disclose corresponding structure, but suggesting that necessary structure cannot be incorporated by reference); Fiber (Fed. Cir. 11/21/19) (non-precedential) (aff’g indefiniteness; material incorporated by reference cannot provide the corresponding structure for a means-plus-function element); citing Default Proof. But see Otto Bock (Fed. Cir. 02/18/14) (non-precedential) (corresponding structure may be incorporated from a U.S. pat. or patent app. but not via incorporation by reference of a non-patent publication, without mentioning if application was published: “Atmel only foreclosed the use of the content of a nonpatent publication incorporated by reference to add structure to a means-plus-function claim.”); 37 C.F.R. § 1.57(d) (support for a Sec. 112(6/f) element is “essential material,” and may be incorporated from only a U.S. patent or published U.S. patent application). Cf. Hayward (Fed. Cir. 02/07/18) (non-precedential) (aff’g PTAB that incorporated priority application supplied written description support, arguably implying that but for incorporation the priority application would not have mattered. Rejecting argument that publication of the priority application only after the filing of the application in question disqualified it from providing § 112 support.”).
Clear Link To Corresponding Structure Cannot Be In Only Non-Incorporated Priority Application Whose Structure Was Omitted From Spec.: A foreign-language, foreign “priority document, whose potentially relevant disclosure was omitted from the United States patent application family, [held not to] provide[] a clear link or association between the claimed” functional elements and any structure disclosed in the patent. Team Worldwide (Fed. Cir. 09/09/21) (non-precedential).
Corresponding Structure Cannot Be A Human: “a human being cannot constitute a ‘means’” within the scope of § 112, ¶ 6.” Voter Verified (Fed. Cir. 11/05/12).
Sec. 112(6/f) Construction And Computers/Processors: see discussion below under Indefiniteness (e.g., “Aristocrat”).
Claim Element Comprises Claim Language And Corresponding Structure And Equivalents: Means-plus-function claim limitations “‘comprise not only the language of the claims, but also the structure corresponding to that means that is disclosed in the written description portion of the specification (and equivalents thereof).’” Uniloc (Fed. Cir. 10/23/17) (non-precedential) (Sec. 112(6/f) element not supported by provisional application’s disclosure, so claim not entitled to provisional’s filing date).
Knowledge Of POSITA Is Relevant To Determine If Some Disclosure Of Algorithm In Spec. Is Adequate; But Irrelevant If Algorithm Is Totally Absent From Spec.: Case law divided into “two distinct groups: First, cases in which the specification discloses no algorithm; and second, cases in which the specification does disclose an algorithm but a [party] contends that disclosure is inadequate.” Where the specification discloses no algorithm, the knowledge of a skilled artisan is irrelevant. But where the specification discloses some arguable algorithm, even if a party contends that the algorithm is inadequate, the sufficiency of the purportedly-adequate structure disclosed in the specification must be evaluated in light of the knowledge possessed by a skilled artisan.” Sisvel (Fed. Cir. 10/06/23) (vacating PTAB ruling that means-plus-function element lacked corresponding algorithm where PTAB erroneously excluded evidence that POSITA would understand the software protocols (known in the art) identified by name in the Spec. Discusses multiple cases).
Expert Testimony Cannot Create Structure Where None Is Adequately Disclosed In The Spec.: Sisvel (Fed. Cir. 10/06/23) (vacating PTAB ruling that means-plus-function element lacked corresponding algorithm. Precedent does “not allow an expert to create new structure or imply structure from background knowledge—instead, it only reads the existing disclosures in the specification for all they “would convey to one skilled in the art.”); Fiber (Fed. Cir. 11/21/19) (non-precedential) (aff’g indefiniteness; “the definiteness requirement is that the specification adequately disclose corresponding structure. Expert testimony cannot create structure where none is adequately disclosed in the specification.”).
- TIPS:
“Structure” Cannot Be Purely Functional (E.g., Any Circuit That Performs The Function): Identifying structure as “any circuit that performs the claim function” is “no more specific than defining” the means “in purely functional terms” which is “prohibited.” Tomita I (Fed. Cir. 12/08/14) (non-precedential) (rev’g district court claim construction).
Breadth Of Structural Equivalents May Be Broader If Specifics Unimportant To Claimed Invention: when the specifics of the disclosed structure are unimportant to the claimed invention, the scope of structural equivalents may be broader. Uniloc (Fed. Cir. 01/04/11) (rev’g JMOL of no infringement).

c) relationship to claim differentiation

Claim Differentiation Does Not Preclude Dependent Claim’s Structure Being The Corresponding Structure For A Sec. 112(6/f) Element: That dependent claim expressly recites the structures identified in the court’s construction of the Sec. 112(6/f) limitation does not argue against that construction, because the Sec. 112(6/f) limitation is still broader than the dependent claim because it also embraces structural equivalents to those structures. Pressure Prod. (Fed. Cir. 03/24/10).
The Opposite Of Claim Differentiation Applies: Where a dependent claim recites that the means-plus-function element comprises a particular structure, that supports a construction that such structure is the “corresponding structure” for that element. Medtronic (Fed. Cir. 04/20/01).