  United States Court of Appeals
      for the Federal Circuit
                ______________________

    DIEBOLD NIXDORF, INC., DIEBOLD SELF-
             SERVICE SYSTEMS,
                 Appellants

                          v.

     INTERNATIONAL TRADE COMMISSION,
                 Appellee

    HYOSUNG TNS INC., NAUTILUS HYOSUNG
               AMERICA INC.,
                  Intervenors
            ______________________

                      2017-2553
                ______________________

   Appeal from the United States International Trade
Commission in Investigation No. 337-TA-989.
                ______________________

               Decided: August 15, 2018
                ______________________

   PATRICK FLINN, Alston & Bird LLP, Atlanta, GA, ar-
gued for appellants.   Also represented by KEITH E.
BROYLES, PAMELA COUNCILL, DAVID FRIST, JOSHUA MARK
WEEKS; ADAM SWAIN, Washington, DC.

   PANYIN HUGHES, Office of the General Counsel, Unit-
ed States International Trade Commission, Washington,
DC, argued for appellee. Also represented by DOMINIC L.
2                               DIEBOLD NIXDORF, INC. v. ITC




BIANCHI, WAYNE W. HERRINGTON.

    GREGORY G. GARRE, Latham & Watkins LLP, Wash-
ington, DC, argued for intervenors. Also represented by
GABRIEL BELL, ELANA NIGHTINGALE DAWSON, KEVIN
WHEELER.
                ______________________

    Before PROST, Chief Judge, BRYSON and O’MALLEY,
                     Circuit Judges.
O’MALLEY, Circuit Judge.
     Appellants Diebold Nixdorf, Inc. and Diebold Self-
Service Systems (together, “Diebold”) appeal the Interna-
tional Trade Commission’s (“ITC” or “Commission”)
finding that they violated § 337 of the Tariff Act of 1930
by importing components of automated teller machines
(“ATMs”) that infringe claims 1–3, 6, 8, and 9 of U.S.
Patent No. 8,523,235 (“the ’235 patent”). Diebold chal-
lenges the Commission’s determination that these claims,
all of which recite the term “cheque standby unit,” are not
invalid for indefiniteness. See Certain Automated Teller
Machines, ATM Modules, Components Thereof, and Prods.
Containing the Same, Inv. No. 337-TA-989, 2017 ITC
LEXIS 1603 (USITC Mar. 13, 2017). It also challenges
the Commission’s construction of certain claim limitations
and its application of those constructions to Diebold’s
accused ATM components and the asserted domestic
industry products. See id.
    We conclude that the term “cheque standby unit” in
the ’235 patent is a means-plus-function term subject to
35 U.S.C. § 112, para. 6, which lacks corresponding struc-
ture disclosed in the specification. We therefore reverse
the Commission’s finding that Diebold violated § 337.
DIEBOLD NIXDORF, INC. v. ITC                                3



                      I. BACKGROUND
                    A. The ’235 Patent
     The ’235 patent describes an ATM—i.e., a “cash and
cheque automatic depositing apparatus”—that is capable
of performing banking transactions, and more particular-
ly is “capable of automatically depositing a bundle of
cashes and cheques inserted at once.” ’235 patent, col. 1,
ll. 6–11. It accomplishes these goals by performing sever-
al steps: (1) separating deposited bundles into individual
banknotes; (2) transferring those notes horizontally
through the ATM; (3) verifying the authenticity or ab-
normality of each note; (4) sorting and processing the
notes based on how each was verified; and (5) preparing
the notes for depositing into storage safes. Id. col. 1, l.
40–col. 2, l. 3.
    One component recited in each of the ’235 patent’s
nine claims is a “cheque standby unit.” The claims specify
that the “cheque standby unit” is “placed in the main
transfer path between the first gate and the second gate”
and is “configured to hold the at least one authentic
cheque to return the at least one authentic cheque to the
user responsive to receiving user instructions cancelling
depositing of the at least one authentic cheque.” Id. col.
10, ll. 50–55.
    The specification does not mention a “cheque standby
unit,” but instead references a “cheque temporary standby
unit” in three portions of the detailed description. First, it
explains that the ATM “includes a cheque temporary
standby unit 120 formed on the main transfer path 106a
provided at a rear side of the first gate 112, for temporari-
ly stopping a transfer of authentic cheques,” as well as
“an endorsement printing unit 122 followed by the cheque
temporary standby unit 120 on the main transfer path
106a, for printing endorsement information on the au-
thentic cheques according to printing instructions.” Id.
4                                  DIEBOLD NIXDORF, INC. v. ITC




col. 2, l. 62–col. 3, l. 2. It later explains the function of the
cheque temporary standby unit in more detail:
    the cheque temporary standby unit 120 formed on
    a specific section of the main transfer
    path 106a between the first gate 112 and the
    main transfer path 106a temporarily stops a
    transfer of authentic cheques verified by the
    banknote verifying unit 110. Before the cheques
    are subjected to an endorsement printing indicat-
    ing that the rights relating to the cheques are
    transferred from customers to the bank, the
    cheques are held for the user as an owner to input
    an instruction. When a depositing instruction is
    inputted, the cheques are transferred to the en-
    dorsement printing unit 122. On the contrary,
    when a depositing cancellation instruction is in-
    putted, the cheques are transferred to the bundle
    insertion opening 102 or the abnormal banknote
    temporary storage 116 by a reverse driving of the
    main transfer unit 106 so that they can be re-
    turned to the user.
    The endorsement printing unit 122 performs the
    endorsement printing only when the banknote
    verifying unit 110 verifies that the cheques are
    authentic and, also, when the cheque temporary
    standby unit 120 receives an owner’s final depos-
    iting instruction.
Id. col. 5, ll. 40–59. Finally, the specification describes “a
preferable entire operation” of the invention, in which
checks that have been separated and transferred along
the main transfer path “are temporarily held by the
cheque temporary standby unit 120 formed on a specific
section of the main transfer path 106a,” where they are
held until a user selects either a depositing consent or
cancellation. Id. col. 7, l. 65–col. 8, l. 6. “Cheque tempo-
DIEBOLD NIXDORF, INC. v. ITC                             5



rary standby unit 120” is depicted on the right-hand side
of Figure 2:




The “cheque standby unit” limitation was added during
prosecution to overcome prior art that purportedly per-
mitted cheques to be stored in a safe, but did not disclose
returning stored cheques to the user after the user can-
celed a deposit. J.A. 559–61, 564–65.
                  B. The ITC Proceedings
    In February 2016, Intervenors Hyosung TNS Inc. and
Nautilus Hyosung America Inc. (together, “Hyosung”),
which own the ’235 patent by assignment, filed a com-
plaint with the ITC against Diebold, 1 alleging violations
of § 337 by reason of Diebold’s infringement of four pa-
tents related to ATMs. The Commission instituted an



    1  During the pendency of the ITC proceedings,
Diebold acquired the majority of shares of German ATM
manufacturer Wincor Nixdorf, Inc., and was renamed
Diebold Nixdorf, Inc.
6                               DIEBOLD NIXDORF, INC. v. ITC




investigation, and three of the four patents—all but the
’235 patent—were subsequently terminated from the
investigation pursuant to motions by Hyosung. The
accused products are Diebold’s ATMs that can receive and
process both cash and checks in a single, mixed bundle
that is inserted at once, and a module used in these
ATMs. J.A. 76–77.
    The administrative law judge (“ALJ”), after holding
an evidentiary hearing, issued an Initial Decision, finding
not only that the accused module directly infringed claims
1–3, 6, 8, and 9 of the ’235 patent and that Diebold con-
tributorily infringed the claims by importing the module,
but also that the claims of the ’235 patent are not invalid.
In relevant part, the ALJ concluded that the term “cheque
standby unit” is not indefinite. First, he agreed with
Hyosung that the term should be given its plain and
ordinary meaning, concluding that a person of ordinary
skill in the art “would understand that a structure in an
ATM that temporarily holds checks pending the customer
confirming the deposit is the cheque standby unit,” and
that, “[i]n general, a cheque standby unit is the escrow
that temporarily holds checks.” J.A. 141. He expressly
credited the testimony of Hyosung’s expert, Dr. Howard,
stating he “described how the phrase ‘a cheque standby
unit’ would necessarily have a structural meaning to such
a person, and would refer to the physical portion of a
cash-and-check depositing module that is comprised of
well-known components for holding cheques in a standby
configuration pending user confirmation of the deposit.”
J.A. 141.
    The ALJ also examined the claim limitation under the
assumption that “cheque standby unit” is a means-plus-
function term, and determined that the ’235 patent dis-
closes the required structure of “stacking and temporary
storage of media.” J.A. 142. The ALJ then stated that a
person of ordinary skill in the art would find correspond-
ing structure in Figure 2’s teaching of “a cheque standby
DIEBOLD NIXDORF, INC. v. ITC                              7



unit 120 that temporarily stores at least one authentic
cheque by holding it in position on the belt.” J.A. 142.
    The Commission, after undertaking review of the
ALJ’s Initial Decision on issues not involving the “cheque
standby unit,” issued its Final Determination finding a
violation of § 337, in addition to a Limited Exclusion
Order and Cease and Desist Orders. Diebold appeals. We
have jurisdiction under 28 U.S.C. § 1295(a)(6).
                       II. DISCUSSION
    Diebold argues on appeal that “cheque standby unit”
is a purely functional term that connotes no specific
structure and is therefore subject to § 112, para. 6. 2
Specifically, it contends that the word “unit” is a “generic
nonce word” akin to “‘mechanism,’ ‘element,’ ‘device,’ and
other nonce words that reflect nothing more than verbal
constructs,” Appellant Br. 30 (quoting Williamson v.
Citrix Online, LLC, 792 F.3d 1339, 1350 (Fed. Cir. 2015)
(en banc)), and highlights that the ’235 patent recites
thirteen different “unit” elements in the claims, each of
which has a unique function. Diebold explains that the
specification includes no discussion of a specific structure
of the “cheque standby unit,” and instead defines the term
exclusively by its function and location. It then points out
that Hyosung’s expert did not testify that the term
“cheque standby unit” connotes sufficiently definite struc-
ture, but instead testified that the term encompasses all
structures capable of fulfilling the function of temporarily
holding checks pending the customer confirming the
deposit, including a nonexhaustive list of structures as
varied as a “suction cup,” a “trap door,” and a “drum.”




    2   Because the application leading to the ’235 patent
was filed prior to September 16, 2012, we apply pre-AIA
§ 112.
8                               DIEBOLD NIXDORF, INC. v. ITC




    The Commission and Hyosung first respond by argu-
ing that Diebold failed to present evidence of its own to
rebut the presumption that § 112, para. 6 does not apply
to this term. Second, they contend that the ALJ properly
determined that the term is not subject to application of
this provision because both the intrinsic and extrinsic
evidence—in particular, the expert testimony of Dr.
Howard—demonstrate that a person of ordinary skill in
the art would understand the term “cheque standby unit”
to denote structure. Finally, Hyosung argues that, even if
the term is subject to § 112, para. 6, the specification
recites sufficient structure for performing the claimed
function in Figure 2, in view of Dr. Howard’s testimony.
                 A. Standards of Review
     We review the Commission’s final determinations un-
der the standards of the Administrative Procedure Act
(“APA”). See 19 U.S.C. § 1337(c) (stating that “[a]ny
person adversely affected by a final determination of the
Commission” may appeal to this court “for review in
accordance with chapter 7 of title 5”). Under the APA, we
review legal determinations de novo and findings of fact
for substantial evidence. Ajinomoto Co., Inc. v. Int’l Trade
Comm’n, 597 F.3d 1267, 1272 (Fed. Cir. 2010); Osram
GmbH v. Int’l Trade Comm’n, 505 F.3d 1351, 1355 (Fed.
Cir. 2007).
    “Regarding questions of claim construction, including
whether claim language invokes 35 U.S.C. § 112, para. 6,”
a trial court’s “determinations based on evidence intrinsic
to the patent as well as its ultimate interpretations of the
patent claims are legal questions that we review de novo.”
Williamson, 792 F.3d at 1346 (citing Teva Pharm. USA,
Inc. v. Sandoz, Inc., –– U.S. ––, 135 S. Ct. 831, 840–41
(2015)); see also Cisco Sys., Inc. v. Int’l Trade Comm’n,
873 F.3d 1354, 1360 (Fed. Cir. 2017) (“We review the
Commission’s claim construction determinations de novo
DIEBOLD NIXDORF, INC. v. ITC                               9



except for subsidiary facts based on extrinsic evidence,
which we review for clear error.”).
              B. Section 112, Para. 6 Applies
    We conclude that the term “cheque standby unit” is
subject to the application of § 112, para. 6. Means-plus-
function claiming occurs when a claim term is drafted in a
manner that invokes § 112, para. 6, which states:
    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 correspond-
    ing structure, material, or acts described in the
    specification and equivalents thereof.
35 U.S.C. § 112, ¶ 6 (2006). As this court stated en banc
in Williamson, Congress, in enacting this provision,
“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 limita-
tion is to be construed”—that is, by restricting the “scope
of coverage to only the structure, materials, or acts de-
scribed in the specification as corresponding to the
claimed function and equivalents thereof.” 792 F.3d at
1347.
    The standard by which we determine whether § 112,
para. 6 applies “is 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.”
Id. at 1349 (citing Greenberg v. Ethicon Endo-Surgery,
Inc., 91 F.3d 1580, 1583 (Fed. Cir. 1996)). As a procedural
matter, to determine whether § 112, para. 6 applies to a
claim limitation, we first look to whether the limitation
uses the word “means.” If so, there is a rebuttable pre-
sumption that § 112, para. 6 applies; if not, there is a
10                               DIEBOLD NIXDORF, INC. v. ITC




rebuttable presumption that the provision does not apply.
Id. at 1348–49. Where, as here, a claim term lacks the
word “means,” the presumption can be overcome
and § 112, para. 6 will apply if the challenger demon-
strates that the claim term fails to “recite sufficiently
definite structure” or else recites “function without recit-
ing sufficient structure for performing that function.” Id.
at 1349 (quoting Watts v. XL Sys., Inc., 232 F.3d 877, 880
(Fed. Cir. 2000)).
    Diebold has shown that the term “cheque standby
unit,” as understood by one of ordinary skill in the
art, both fails to recite sufficiently definite structure and
recites a function without reciting sufficient structure for
performing that function. Examining the evidence intrin-
sic to the ’235 patent, we observe that the claims do not
recite any structure, much less “sufficiently definite
structure,” for the “cheque standby unit.” Rather, the
claims describe the term “cheque standby unit” solely in
relation to its function and location in the apparatus.
Claim 1 specifies that the unit must be “placed in the
main transfer path between the first gate and the second
gate” and requires that it be “configured to hold the at
least one authentic cheque to return the at least one
authentic cheque to the user responsive to receiving user
instructions cancelling depositing of the at least one
authentic cheque.” ’235 patent, col. 10, ll. 50–55. None of
the dependent claims add limitations that either describe
particular structural features or flesh out whether the
term has a particular structural meaning. And the speci-
fication similarly explains that the “cheque temporary
standby unit” is “formed on the main transfer path 106a”
and is used to “temporarily stop[ ] a transfer of authentic
cheques,” without making clear what, if any, structures
correspond to the claim term. Id. col. 2, l. 62–col. 3, l. 2.
Indeed, although the specification includes a drawing,
Figure 2, which purports to illustrate the term, it depicts
“cheque temporary standby unit 120” as a vertical line
DIEBOLD NIXDORF, INC. v. ITC                               11



indistinguishable from the “main transfer path 106a” that
both precedes and follows it and on which it is “formed.”
Id. at Fig. 2.
    Although these passages suggest that the “cheque
standby unit” must have some structure to perform the
function of holding checks and then either returning them
to the user or continuing to process them pending a user
instruction, the ’235 patent does not offer any clues as to
what such a structure might be. 3 Indeed, the written
description does not include any examples of what struc-
tures or class of structures fall within the definition of a
“cheque standby unit.” Nor does the fact the “cheque



    3    At oral argument, counsel for the Commission for
the first time mentioned a patent application incorporated
by reference in the ’235 patent’s specification, arguing
that element 114 of this incorporated patent application,
referred to as a “temporary standby unit,” shows a struc-
ture corresponding to the “cheque standby unit.” Oral
Arg.         at       18:14–19:33,        available         at
http://oralarguments.cafc. uscourts.gov/default.aspx?fl=20
17-2553.mp3 (referencing J.A. 5585). Putting aside the
question of waiver, counsel admitted that the section of
the ’235 patent in which this application is incorporated is
directed only to the invention’s tripartite sensors. Id. at
21:15–26. The extent to which material has been incorpo-
rated by reference into a host document is a question of
law, Advanced Display Systems, Inc. v. Kent State Univer-
sity, 212 F.3d 1272, 1283 (Fed. Cir. 2000), and we con-
clude that the ’235 patent’s incorporation of this applica-
application expressly for its “detailed description” of two
sensors is insufficient to incorporate the application for its
“temporary standby unit,” ’235 patent, col. 5, ll. 3–6.
Counsel admitted, moreover, that the Commission did not
rely on this incorporated application, but relied instead on
the testimony of Dr. Howard. Oral Arg. at 20:00–07.
12                              DIEBOLD NIXDORF, INC. v. ITC




standby unit” must be formed on the main transfer unit
between the first and second gates offer any guidance
“that might inform the structural character of the limita-
tion-in-question or otherwise impart structure” to the
term as recited in the claims, Williamson, 792 F.3d at
1351, particularly where the lone figure in which the unit
is depicted illustrates no corresponding structure.
    Our analysis of whether § 112, para. 6 applies does
not end with this observation, however, as the Commis-
sion credited Dr. Howard’s expert testimony in determin-
ing that the term “cheque standby unit” connotes
sufficiently definite meaning as the name for structure to
persons of ordinary skill in the art. Diebold argues that,
because this testimony was based purely on Dr. Howard’s
interpretation of the intrinsic record, we should decline to
consider it and review the Commission’s claim construc-
tion de novo. Diebold further argues that, even if the
Commission was entitled to rely on Dr. Howard’s testimo-
ny, we should nevertheless reverse because he testified
that the term “cheque standby unit” fails to connote any
particular structure.
     The Commission and Hyosung raise two arguments in
response. First, they contend that, because Diebold failed
to present affirmative evidence of how a person of ordi-
nary skill would understand the claim language, Diebold
failed to rebut the presumption against the application of
§ 112, para. 6. Second, they submit both that the Com-
mission was entitled to credit Dr. Howard’s testimony,
and that such testimony was sufficient to demonstrate
that the term “cheque standby unit” had a structural
meaning to persons of skill in the art at the relevant time.
We reject both of the Commission and Hyosung’s argu-
ments, and conclude that the term is subject to § 112,
para. 6.
    First, none of our cases mandate that a party seeking
to overcome the presumption against application of § 112,
DIEBOLD NIXDORF, INC. v. ITC                               13



para. 6 can only do so by presenting extrinsic evidence
that one of ordinary skill would fail to understand that a
term connotes a definite structure. Imposing such a
requirement would be inconsistent with the Supreme
Court’s guidance in Teva Pharmaceuticals, where the
Court held that, even in cases in which the district court
finds a need to look beyond the patent’s intrinsic evidence
and to consult extrinsic evidence, the district court must
still conduct a legal analysis: “whether a skilled artisan
would ascribe that same meaning to that term in the
context of the specific patent claim under review.” 135 S.
Ct. at 841. This is because “‘[e]xperts may be examined to
explain terms of art, and the state of the art, at any given
time,’ but they cannot be used to prove ‘the proper or legal
construction of any instrument of writing.’” Id. (alteration
in original) (quoting Winans v. N.Y. & Erie R. Co., 21
How. 88, 100–01 (1859)). In short, trial courts, after
deciding factual disputes, must interpret patent claims in
light of the facts that they found—“[t]his ultimate inter-
pretation is a legal conclusion,” and “appellate court[s]
can still review the [tribunal’s] ultimate construction of
the claim de novo.” Id. We specifically applied Teva’s
holding in the context of § 112, para. 6 in Skky, Inc. v.
MindGeek, s.a.r.l., 859 F.3d 1014 (Fed. Cir. 2017), ex-
plaining that “[t]he task of determining whether the
relevant claim language contains a means-plus-function
limitation is . . . a question of law that we review de novo.”
Id. at 1019 (alteration in original) (quoting TriMed, Inc. v.
Stryker Corp., 514 F.3d 1256, 1259 (Fed. Cir. 2008)).
    Thus, in appropriate cases, a party advocating that a
claim limitation that does not recite the word “means” is
subject to § 112, para. 6 can overcome the presumption
against its application solely by reference to evidence
intrinsic to the patent. Diebold’s failure to contradict Dr.
Howard’s testimony with extrinsic evidence is not fatal to
its ability to overcome the presumption, as the Commis-
sion and Hyosung argue, unless we conclude that Dr.
14                              DIEBOLD NIXDORF, INC. v. ITC




Howard’s testimony was sufficient to overcome conclu-
sions drawn from the intrinsic record. We conclude it was
not.
    The Commission relied on paragraphs 185, 186, and
189 of Dr. Howard’s Witness Statement in determining
that the term “cheque standby unit” is not a means-plus-
function term. It did not cite, and Hyosung did not intro-
duce, any other evidence, such as dictionary definitions,
suggesting that “cheque standby unit” is a term commonly
understood by persons of ordinary skill in the art to
denote a device or class of devices. Cf. Greenberg, 91 F.3d
at 1583 (relying on dictionary definitions that “make clear
that the noun ‘detent’ denotes a type of device with a
generally understood meaning in the mechanical arts,
even though the definitions are expressed in functional
terms,” and explaining that what matters is whether “the
term, as the name for structure, has a reasonably well
understood meaning in the art”). But, even crediting the
entirety of Dr. Howard’s testimony, we conclude, as a
matter of law, that the term “cheque standby unit” is
subject to the application of § 112, para. 6.
    The Commission relied on Dr. Howard’s testimony
that “a person of ordinary skill in the art would readily
understand that a structure in an ATM that temporarily
holds checks pending the customer confirming the deposit
is the cheque standby unit,” and that, “[i]n general, a
cheque standby unit is the escrow that temporarily holds
checks.” J.A. 3219 ¶ 186. It also relied on his testimony
that the term “would necessarily have a structural mean-
ing” to a person of ordinary skill in the art, who would
understand the unit must be “comprised of well-known
components for holding cheques in a standby configura-
tion pending user confirmation of the deposit,” and must
“interface with the main transfer path.” J.A. 3219–20
¶ 189. And it credited his testimony that “[a] person of
ordinary skill in the art would also understand the stack-
DIEBOLD NIXDORF, INC. v. ITC                              15



ing and temporary storage of media in figure 2” of the ’235
patent in a different portion of its ID. J.A. 3222 ¶ 192.
    None of these findings demonstrate that the term
“cheque standby unit” had a reasonably well understood
meaning in the art at the time of the invention. Green-
berg, 91 F.3d at 1583. Adopting the approach taken by
the inventors of the ’235 patent, Dr. Howard offered
purely functional definitions of the term “cheque standby
unit.” Nowhere in his testimony does he explain with any
degree of definiteness what structure or class of struc-
tures a person of ordinary skill would understand the
term to encompass. He did not define an “escrow,” did not
explain what “well-known components” a skilled artisan
would understand could be used to design a “cheque
standby unit,” and did not articulate how the fact that the
“cheque standby unit” must “interface with the main
transfer path” dictates any aspect of the unit’s structure. 4



    4    At oral argument, counsel for Hyosung argued
that Dr. Howard’s oral testimony that “escrow units” were
“well known” demonstrates that persons of ordinary skill
in the art knew the equivalent term “cheque standby
unit” is a sufficiently definite name for structure. See J.A.
1631:12–20. He invited the court to “Google ATM escrow
unit” to see that the term has a specific, structural mean-
ing to persons of ordinary skill, akin to words like “brake,”
“lock,” and “screwdriver.” Oral Arg. at 26:00–26:13.
Hyosung did not present any such evidence to the Com-
mission, however, nor did the Commission find that the
term “escrow unit” conveys a particular structural mean-
ing to skilled artisans. Counsel for Hyosung also express-
ly declined to conclude that the scope of the term “cheque
standby unit” is limited to structures falling in the pur-
portedly well-understood group of structures known as
“escrow units.” Id. at 26:13–26:24. And, counsel present-
ed no evidence or argument indicating that the “escrow
16                              DIEBOLD NIXDORF, INC. v. ITC




He likewise failed to offer any structural limitation that
might serve to cabin the scope of the functional term. In
essence, Dr. Howard did little more than opine that a
skilled artisan would understand the functional term
“cheque standby unit” to be any structure capable of
performing the claimed function. 5 Hyosung offered no
other extrinsic evidence to demonstrate that the term
“cheque standby unit” has a sufficiently definite structur-
al meaning to persons of ordinary skill in the art, and the
Commission made no such fact-findings.
     This case is therefore distinguishable from the cases
on which the Commission and Hyosung rely. First, in
Inventio AG v. Thyssenkrupp Elevator Americas Corp.,
649 F.3d 1350 (Fed. Cir. 2011), overruled on other grounds
by Williamson, 792 F.3d at 1339, we found that the writ-
ten descriptions of the patents “indicate[d] that the ‘com-
puting unit’ connotes structure to skilled artisans” by
expressly referring to the computing unit as “a commer-
cially available personal computer or workstation” and by
noting that the term includes “at least one processor and
at least one data memory.” Id. at 1359–60. Here, by
contrast, the specification does not describe what an
exemplary “cheque standby unit” might be, nor does it
describe a class of structures to which the “cheque
standby unit” belongs.




units” to which he referred either existed or were well
known as of the date of the application for the ’235 patent.
For these reasons, we do not countenance Hyosung’s
arguments concerning “escrow units.”
    5   As noted, during trial before the Commission, Dr.
Howard testified that, in his opinion, the phrase “cheque
standby unit” was broad enough to cover structures as
distinct as a suction cup, a trapdoor, and a drum, without
limitation.
DIEBOLD NIXDORF, INC. v. ITC                               17



     In Apex Inc. v. Raritan Computer, Inc., 325 F.3d 1364
(Fed. Cir. 2003), we considered whether claim limitations
reciting “circuits” were subject to § 112, ¶ 6. We began by
noting that the term “circuit,” which one dictionary de-
fines as “the combination of a number of electrical devices
and conductors that, when interconnected to form a
conducting path, fulfill some desired function,” “by itself
connotes some structure,” and explained that “the term
‘circuit’ with an appropriate identifier such as ‘interface,’
‘programming’ and ‘logic,’ certainly identifies some struc-
tural meaning to one of ordinary skill in the art.” Id. at
1373. We then observed that nothing in the specification
or prosecution history was inconsistent with the ordinary
meaning of the term “circuit,” and pointed out that the
Raritan’s experts’ testimony “show[ed] only that the term
‘circuit’ is understood by one of ordinary skill in the art as
a very broad term and that one of the accused products
included several of the circuit elements.” Id. at 1373–74.
Here, however, the word “unit,” which the ’235 patent
uses to describe thirteen distinct components of the
invention, does not, standing alone, connote any particu-
lar structure. Nor is sufficient structure imparted by
modifying the word “unit” with the words “cheque” and
“standby” or by specifying the location of the “cheque
standby unit.” The ’235 patent offers no guidance as to
what structure or class of structures “placed in the main
transfer path” might be capable of performing the func-
tion of holding checks pending user instructions.
    Finally, in Greenberg, we were tasked with deciding
whether the term “detent mechanism” was subject to
§ 112, para. 6. The district court concluded that it was,
both because the term did not describe a particular struc-
ture but instead described any structure that performed a
detent function, and because both the dictionary defini-
tion of the word “detent” and the definition of “detent
mechanism” offered by Dr. Greenberg’s expert “were
expressed in functional terms.” 91 F.3d at 1583. We
18                               DIEBOLD NIXDORF, INC. v. ITC




disagreed. First, we recognized that “[m]any devices take
their names from the functions they perform,” including
“filter,” “brake,” and “clamp,” and concluded that “detent”
is “just such a term.” Id. We explained that dictionary
definitions “make clear that the noun ‘detent’ denotes a
type of device with a generally understood meaning in the
mechanical arts, even though the definitions are ex-
pressed in functional terms.” Id. And although “the term
‘detent’ does not call to mind a single well-defined struc-
ture,” we observed that “the same could be said of other
commonplace structural terms such as ‘clamp’ or ‘contain-
er.’” Id. “What is important is not simply that a ‘detent’
or ‘detent mechanism’ is defined in terms of what it does,
but that the term, as the name for structure, has a rea-
sonably well understood meaning in the art.” Id.
    This case is unlike Greenberg, as there is no evi-
dence—in the form of dictionary definitions or other-
wise—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. See Skky, 859 F.3d at
1019 (stating that a limitation may recite sufficiently
definite structure “even if the term covers a broad class of
structures and even if the term identifies the structures
by their function” (quoting TecSec, Inc. v. Int’l Bus.
Machs. Corp., 731 F.3d 1336, 1347 (Fed. Cir. 2013))). All
the record contains is one expert’s unsupported, and
largely unhelpful, opinion that skilled artisans would
have understood that a “cheque standby unit” has a
particular function and can be made of “well-known
components for holding cheques in a standby configura-
tion pending user confirmation of the deposit.”
    Instead, we find this case to be analogous to Advanced
Ground Information Systems, Inc. v. Life360, Inc., 830
F.3d 1341 (Fed. Cir. 2016), which concerned the term
“symbol generator.” There, we held that the term “symbol
generator” invokes the application of § 112, para. 6 be-
cause “it fails to describe a sufficient structure and other-
DIEBOLD NIXDORF, INC. v. ITC                            19



wise recites abstract elements ‘for’ causing actions,” or
“elements ‘that can’ perform functions.” Id. at 1347–48.
In relevant part, we rejected the patentee’s argument that
its expert presented unrebutted testimony that those
skilled in the art would have understood what a “symbol
generator” is, and would have known how to select and
use one from the well-known class of software modules,
for two reasons. First, we observed that the expert “testi-
fied that the term ‘symbol generator’ is a term coined for
the purposes of the patents-in-suit.” Id. at 1348. Second,
we pointed out that there was no evidence that the term
was “used in ‘common parlance or by persons of skill in
the pertinent art to designate structure,’ such that it
connotes sufficient structure to avoid the application of”
§ 112, para. 6. Id. (quoting Lighting World, Inc. v. Birch-
wood Lighting, Inc., 382 F.3d 1354, 1359 (Fed. Cir.
2004), overruled on other grounds by Williamson, 792 F.3d
at 1348–49). Here, too, neither the Commission nor
Hyosung point to documentary evidence that the term
“cheque standby unit” was used either in “common par-
lance” or by skilled artisans in the pertinent field to
designate structure. Id. Nor do they dispute Diebold’s
contention that the term, which was added to the claims
during prosecution, was “coined by the applicant himself
for purposes of claiming his invention.” Appellant Br. 31.
          C. The Specification Does Not Disclose
            Sufficient Structure Corresponding
                  to the Claimed Function
     Having concluded that the term “cheque standby unit”
is subject to application of § 112, para. 6, we next deter-
mine whether the specification discloses sufficient struc-
ture that corresponds to the claimed function, which the
parties do not dispute is “holding the at least one authen-
tic cheque to return the at least one authentic cheque to
the user responsive to receiving user instructions cancel-
ling depositing of the at least one authentic cheque.” It
does not.
20                               DIEBOLD NIXDORF, INC. v. ITC




    “Structure disclosed in the specification qualifies as
‘corresponding structure’ if the intrinsic evidence clearly
links or associates that structure to the function recited in
the claim.” Williamson, 792 F.3d at 1352 (citing Noah
Sys., Inc. v. Intuit Inc., 675 F.3d 1302, 1311 (Fed. Cir.
2012)). “Even if the specification discloses corresponding
structure, the disclosure must be of ‘adequate’ correspond-
ing structure to achieve the claimed function.” Id. (cita-
tion omitted). Thus, under § 112, paras. 2 and 6, if a
person of ordinary skill in the art would be unable to
recognize the structure in the specification and associate
it with the corresponding function in the claim, a means-
plus-function clause is indefinite. Id. (citation omitted).
    Although the Commission found that “[f]igure 2 of the
’235 patent teaches a cheque standby unit 120 that tem-
porarily stores at least one authentic cheque by holding it
in position on the belt,” J.A. 142, no structure is disclosed
in the figure or written description that is capable of
performing this function. Instead, all that is depicted in
the figure for item 120 is a pair of vertical lines that
wraps around the outside of two cylinders. These lines
are indistinguishable from main transfer unit 106a,
which both precedes and follows item 120. The corre-
sponding portions of the written description likewise do
not describe any structure capable of “holding [cheques] in
position on the belt.” Nor does the written description—
including the portions cited by the Commission—
reference “the stacking and temporary storage of media.”
Cf. J.A. 142. Even had the specification included this
phrase, it would still describe only function, not structure,
and therefore would be insufficient to constitute “‘ade-
quate’ corresponding structure to achieve the claimed
function.” Williamson, 792 F.3d at 1352.
    Because the ’235 patent fails to disclose any structure
corresponding to the function of “holding the at least one
authentic cheque to return the at least one authentic
cheque to the user responsive to receiving user instruc-
DIEBOLD NIXDORF, INC. v. ITC                           21



tions cancelling depositing of the at least one authentic
cheque,” we conclude that claims 1–3, 6, 8, and 9 are
invalid for indefiniteness under 35 U.S.C. § 112, para. 2.
                      III. CONCLUSION
    For the foregoing reasons, we reverse the Commis-
sion’s finding that Diebold violated § 337.
                       REVERSED
                           COSTS
    Costs to appellant.
