  United States Court of Appeals
      for the Federal Circuit
                ______________________

                 ONE-E-WAY, INC.,
                    Appellant

                          v.

     INTERNATIONAL TRADE COMMISSION,
                 Appellee

SONY CORPORATION, SONY CORPORATION OF
AMERICA, SONY ELECTRONICS, INC., BLUEANT
WIRELESS PTY, LTD., BLUEANT WIRELESS, INC.,
CREATIVE TECHNOLOGY LTD., CREATIVE LABS,
           INC., GN NETCOM A/S,
                  Intervenors
            ______________________

                      2016-2105
                ______________________

   Appeal from the United States International Trade
Commission in Investigation No. 337-TA-943.
                ______________________

                Decided: June 12, 2017
                ______________________

    DOUGLAS GLEN MUEHLHAUSER, Knobbe, Martens, Ol-
son & Bear, LLP, Irvine, CA, argued for appellant. Also
represented by CAMERON JAHANSOUZ, ALAN GRAYSON
LAQUER, PAYSON J. LEMEILLEUR.
2                                     ONE-E-WAY, INC.   v. ITC



   MEGAN MICHELE VALENTINE, Office of the General
Counsel, United States International Trade Commission,
Washington, DC, argued for appellee. Also represented by
DOMINIC L. BIANCHI, WAYNE W. HERRINGTON.

    JOHN FLOCK, Andrews Kurth Kenyon LLP, New York,
NY, argued for all intervenors. Intervenors Sony Corpora-
tion, Sony Corporation of America, Sony Electronics, Inc.,
also represented by KSENIA TAKHISTOVA; PAUL T. QUALEY,
AIMEE NOELLE SOUCIE, Washington, DC.

   DUANE H. MATHIOWETZ, LeClair Ryan, San Francisco,
CA, for intervenors Blueant Wireless Pty, Ltd., Blueant
Wireless, Inc. Also represented by PATRICIA LYNN PEDEN.

   JONATHAN DANIEL BAKER, Farney Daniels PC, San
Mateo, CA, for intervenors Creative Technology Ltd.,
Creative Labs, Inc. Also represented by MICHAEL D.
SAUNDERS, GURTEJ SINGH.

    WILLIAM B. NASH, Haynes and Boone LLP, San Anto-
nio, TX, for intervenor GN Netcom A/S. Also represented
by JASON WAYNE WHITNEY; GLENN WESTREICH, San Jose,
CA.
                  ______________________

Before PROST, Chief Judge, WALLACH, and STOLL, Circuit
                       Judges.
    Opinion for the court filed by Circuit Judge STOLL.
     Dissenting opinion filed by Chief Judge PROST.
STOLL, Circuit Judge.
    The International Trade Commission found the claim
term “virtually free from interference” indefinite and
invalidated the asserted claims of One-E-Way’s patents.
Because we conclude that the term “virtually free from
interference,” as properly interpreted in light of the
ONE-E-WAY, INC.   v. ITC                                  3



specification and prosecution history, would inform a
person of ordinary skill in the art about the scope of the
invention with reasonable certainty, we reverse.
                           BACKGROUND
                               I.
    One-E-Way filed a complaint with the International
Trade Commission accusing, among others, Respondents
Sony Corporation; Sony Corporation of America; Sony
Electronics, Inc.; BlueAnt Wireless Pty, Ltd.; BlueAnt
Wireless, Inc.; Creative Technology Ltd.; Creative Labs,
Inc.; and GN Netcom A/S (collectively, “Respondents”) of
infringing two of its related patents, U.S. Patent
Nos. 7,865,258 and 8,131,391. One-E-Way asserted, inter
alia, claim 8 of the ’258 patent and claims 1, 3–6, and 10
of the ’391 patent.
                               II.
    Both patents disclose a wireless digital audio system
designed to let people use wireless headphones privately,
without interference, even when multiple people are using
wireless headphones in the same space. ’258 patent,
Abstract. 1 The specification explains that previous wire-
less digital audio systems did not, among other things,
provide “private listening without interference where
multiple users occupying the same space are operating
wireless transmission devices.” Id. at col. 1 ll. 15–49. The
specification further explains that the prior art “audio
systems ma[de] use of electrical wire connections between
the audio source and the headphones to accomplish pri-
vate listening to multiple users.” Id. at col. 1 ll. 40–42.



   1    Because the ’258 and ’391 patents share the same
specification, we cite only to the ’258 patent, with the
understanding that these citations also refer to the corre-
sponding sections of the ’391 patent.
4                                     ONE-E-WAY, INC.   v. ITC



     The patents purport to solve these problems in the
prior art by disclosing a digital wireless audio system that
ensures private listening. Specifically, the patent specifi-
cation proposes changing the way prior art systems sent
and processed the wireless signal. It suggests sending a
digitally encoded signal to ensure each user can inde-
pendently access his or her transmission. Id. at col. 3
ll. 16–18. It further suggests processing the signal with a
fuzzy logic detection subsystem to enhance signal clarity.
Id. at col. 3 ll. 40–43, 56–59. These and other improve-
ments enable a user “to listen (privately) to high fidelity
audio music, using any of the audio devices listed previ-
ously, without the use of wires, and without interference
from any other receiver headphone . . . user, even when
operated within a shared space.” Id. at col. 3 ll. 28–32.
                            III.
    At the Commission, the parties disputed whether the
claim term “virtually free from interference” was indefi-
nite. While the term is present in all the asserted claims,
we reproduce claim 8 of the ’258 patent below as illustra-
tive:
    8. A portable wireless digital audio system for dig-
    ital transmission of an original audio signal rep-
    resentation from a portable audio source to a
    digital audio headphone, said portable wireless
    digital audio system comprising:
       a portable digital audio transmitter con-
       figured to couple to said portable audio
       source and transmitting a unique user
       code bit sequence with said original audio
       signal representation in packet format,
       said digital audio transmitter comprising:
       an encoder operative to encode said origi-
       nal audio signal representation to reduce
       intersymbol interference; and
ONE-E-WAY, INC.   v. ITC                               5



        a digital modulator configured for inde-
        pendent code division multiple access
        (CDMA) communication operation; and
        said portable digital audio transmitter
        configured for direct digital wireless com-
        munication with said digital audio head-
        phone, said digital audio headphone
        comprising:
        a direct conversion module configured to
        capture packets embedded in the received
        spread spectrum signal, the captured
        packets corresponding to the unique user
        code bit sequence;
        a digital demodulator configured for inde-
        pendent CDMA communication operation;
        a decoder operative to decode the applied
        reduced intersymbol interference coding of
        said original audio signal representation;
        a digital-to-analog converter (DAC) gener-
        ating an audio output of said original au-
        dio signal representation; and
        a module adapted to reproduce said gen-
        erated audio output, said audio having
        been wirelessly transmitted from said
        portable audio source virtually free from
        interference from device transmitted sig-
        nals operating in the portable wireless
        digital audio system spectrum.
Id. at col. 7 l. 62 – col. 8 l. 27 (emphasis added).
    Respondents and the Commission’s Office of Unfair
Import Investigation (“the Staff”) both asserted that
“virtually free from interference” was indefinite.
One-E-Way, to the contrary, proposed that the term
meant “free from interference such that eavesdropping on
6                                     ONE-E-WAY, INC.   v. ITC



device transmitted signals operating in the . . . wireless
digital audio system spectrum cannot occur.” J.A. 11454.
As the administrative law judge explained, One-E-Way
contended that “the specifications of the asserted patents
provide ‘abundant guidance’ to one of ordinary skill in the
art” to understand that “virtually free from interference”
requires “that users of the invention do not hear each
other’s transmissions.” J.A. 12927. The ALJ conducted a
claim construction hearing and issued a decision finding
“virtually free from interference” indefinite under
35 U.S.C. § 112. J.A. 12921–30.
    Respondents filed a motion for summary determina-
tion that the term “virtually free from interference” is
indefinite, which the ALJ granted. J.A. 6–93. The ALJ
concluded that the “term ‘virtually free from interference’
is not defined in the Asserted Patents or their history”
and does not “have an understood meaning in the rele-
vant art.” J.A. 87. The ALJ explained that he found
“virtually free from interference” to be indefinite because
one of ordinary skill in the art had “no guidepost in the
intrinsic or extrinsic evidence from which [she] could
discern the scope of the limitation.” J.A. 88.
     One-E-Way petitioned the Commission to review the
ALJ’s summary-determination order. J.A. 2. The Com-
mission agreed with the ALJ that “virtually free from
interference” was indefinite. Id. The Commission thus
affirmed the ALJ’s order.
   One-E-Way appealed.       We have jurisdiction under
28 U.S.C. § 1295(a)(6).
                       DISCUSSION
    We review the Commission’s grant of summary de-
termination de novo. Amgen, Inc. v. Int’l Trade Comm’n,
565 F.3d 846, 849 (Fed. Cir. 2009). “Indefiniteness is a
question of law that we review de novo, subject to a de-
termination of underlying facts.” Akzo Nobel Coatings,
ONE-E-WAY, INC.   v. ITC                                  7



Inc. v. Dow Chem. Co., 811 F.3d 1334, 1343
(Fed. Cir. 2016) (internal citation omitted). We presume
that patents are valid, so “[a]ny fact critical to a holding
on indefiniteness . . . must be proven by the challenger by
clear and convincing evidence.” Cox Commc’ns, Inc. v.
Sprint Commc’n Co. LP, 838 F.3d 1224, 1228
(Fed. Cir. 2016) (alteration in original) (quoting Intel
Corp. v. VIA Techs., Inc., 319 F.3d 1357, 1366
(Fed. Cir. 2003)); see also 35 U.S.C. § 282.
                             I.
    The Patent Act requires inventors to claim their in-
vention in “full, clear, concise, and exact terms.”
35 U.S.C. § 112. This indefiniteness requirement is “part
of the delicate balance the law attempts to maintain
between inventors, who rely on the promise of the law to
bring the invention forth, and the public, which should be
encouraged to pursue innovations, creations, and new
ideas beyond the inventor’s exclusive rights.” Festo Corp.
v. Shoketsu Kinzoku Kogyo Kabushiki Co., 535 U.S. 722,
731 (2002). This balance recognizes that all claims suffer
from “the inherent limitations of language,” but also that
claims must “be precise enough to afford clear notice of
what is claimed.” Nautilus, Inc. v. Biosig Instruments,
Inc., 134 S. Ct. 2120, 2128–29 (2014). This balance per-
mits “[s]ome modicum of uncertainty” to “ensur[e] the
appropriate incentives for innovation,” but it also provides
a “meaningful definiteness check” to prevent patent
applicants from “inject[ing] ambiguity into their claims.”
Id. (internal quotations omitted). Recognizing this bal-
ance, the Supreme Court articulated the test for indefi-
niteness as “requir[ing] that a patent’s claims, viewed in
light of the specification and prosecution history, inform
those skilled in the art about the scope of the invention
with reasonable certainty.” Id. at 2129. This test “man-
dates clarity, while recognizing that absolute precision is
unattainable.” Id.
8                                       ONE-E-WAY, INC.   v. ITC



    As long as claim terms satisfy this test, relative terms
and words of degree do not render patent claims invalid.
Interval Licensing LLC v. AOL, Inc., 766 F.3d 1364, 1370
(Fed. Cir. 2014). To determine whether a particular term
is indefinite, “[o]ne must bear in mind . . . that patents
are ‘not addressed to lawyers, or even to the public gener-
ally,’ but rather to those skilled in the relevant art.”
Nautilus, 134 S. Ct. at 2128–29 & n.5 (quoting Carnegie
Steel Co. v. Cambria Iron Co., 185 U.S. 403, 437 (1902),
and citing Eibel Process Co. v. Minn. & Ont. Paper Co.,
261 U.S. 45, 58, 65–66 (1923)). For example, in 1923, the
Supreme Court “uph[eld] as definite a patent for an
improvement to a paper-making machine, which provided
that a wire be placed at a ‘high’ or ‘substantial elevation.’”
Nautilus, 134 S. Ct. at 2129 n.5 (citing Eibel Process,
261 U.S. at 58). The Court explained that these relative
terms—“substantial” and “high”—were sufficiently defi-
nite because “‘readers . . . skilled in the art of paper
making and versed in the use of the . . . machine’ would
have ‘no difficulty . . . in determining . . . the substantial
[elevation] needed’ for the machine to operate as speci-
fied.” Id. (quoting Eibel Process, 261 U.S. at 65–66).
    This historical practice continues today. In one of our
post-Nautilus decisions, we upheld as definite a claim
that employed the relative term “substantially centered.”
Apple Inc. v. Samsung Elecs. Co., 786 F.3d 983, 1002
(Fed. Cir. 2015), rev’d and remanded on other grounds,
137 S. Ct. 429 (2016). The claim term, used in a patent
relating to a user-interface feature, required that a select-
ed portion of an electronic display be enlarged and “sub-
stantially centered” on the display. Id. (quoting U.S.
Patent No. 7,864,163 (Claim 50)). The patent challenger
had failed to adduce any evidence showing that the per-
son of ordinary skill would lack reasonable certainty in
the claim’s scope, while the patent owner had presented
expert testimony that skilled artisans would interpret
“substantially centered” in the patent “to mean essential-
ONE-E-WAY, INC.   v. ITC                                  9



ly centered except for a marginal spacing to accommodate
ancillary graphical user interface elements.” Id. at 1003.
Moreover, the expert’s suggested interpretation of “sub-
stantially centered” paralleled the patent specification’s
disclosure. Id. Relying on these disclosures, the court
concluded that “substantially centered” was not indefi-
nite. Id.
                            II.
    Here, we must determine whether the term “virtually
free from interference” is indefinite. 2 The Commission
determined that the term is indefinite, and both the
Government and Respondents urge affirmance of that
conclusion on appeal. One-E-Way proposes that the claim
term, viewed in light of the specification and prosecution
history, should be interpreted to mean “free from interfer-
ence such that eavesdropping on device transmitted
signals operating in the . . . wireless digital audio system
spectrum cannot occur.” J.A. 11454; Appellant Br. 13.
Put simply, One-E-Way proposes that “virtually free from
interference” prevents one user from eavesdropping on
another. We agree.
                            A.
     First, the claims require that the system user’s audio
is “virtually free from interference” from signals transmit-
ted by other users’ wireless audio transmission devices.
For example, claim 8 of the ’258 patent requires a “digital
audio system comprising . . . a module adapted to repro-


   2    While the parties both focus their argument on
whether the term “virtually free from interference” is
indefinite, the entire disputed claim term differs slightly
in each of the asserted claims, but it takes the following
general form: “virtually free from interference from device
transmitted signals operating in the [wireless digital
audio system] spectrum.” J.A. 11454.
10                                    ONE-E-WAY, INC.   v. ITC



duce . . . generated audio output, said audio having been
wirelessly transmitted from said portable audio source
virtually free from interference from device transmitted
signals operating in the portable wireless digital audio
system spectrum.” ’258 patent col. 7 l. 62 – col. 8 l. 47
(Claim 8) (emphasis added). This claim requires that the
headphone’s audio output be “virtually free from interfer-
ence.” And the claim names the source of this interfer-
ence: signals transmitted by other wireless audio
transmission devices.
    That the claims require a listener’s audio enjoyment
to be “virtually free from interference” from other wire-
less-headphone listeners is not surprising, particularly in
light of the specification’s disclosure. As explained above,
the specification discloses a system that enables wireless
headphone users to enjoy their audio privately, without
interference.
     The specification repeatedly highlights this pri-
vate-listening feature of the claimed invention. And in
each repetition, the specification states that private
listening is “without interference” from other users’
wireless audio transmission devices. For instance, the
background of the invention emphasizes that the prior art
needs a system like the one disclosed in the ’258 patent
capable of “private listening without interference where
multiple users occupying the same space are operating
wireless transmission devices.” Id. at col. 1 ll. 38–40. The
summary of the invention touts the claimed invention as
being capable of “private listening without interference
from other users or wireless devices.” Id. at col. 1 ll. 64–
67. The detailed description additionally features an
embodiment capable of private listening “without inter-
ference from any other receiver headphone . . . user, even
when operated within a shared space.” Id. at col. 3 ll. 30–
32. And the abstract underscores the patented system’s
ability to deliver “private audio enjoyment without inter-
ference from other users of independent wireless digital
ONE-E-WAY, INC.   v. ITC                                  11



transmitters and receivers sharing the same space.” Id.
at Abstract.
    Taken together, the specification makes clear that
private listening is listening without interference from
other users. In other words, the interference would cause
one user to hear another user’s wireless transmissions,
potentially interfering with the utility of a device. The
patented invention sought to prevent such interference,
making it possible for wireless-headphone users to listen
in private. Id. at col. 1 ll. 43–49.
                           B.
    The prosecution history confirms One-E-Way’s inter-
pretation of “virtually free from interference.” During
prosecution of the related parent patent, 3 the applicant
explained that the term “virtually free from interference”
results in the ability to listen without eavesdropping:
   As is agreed to by the Applicant and Examiner,
   most recently discussed during the teleconference
   with the Examiner on June 3, 2009, Lavelle [prior
   art] does not teach, disclose, or suggest such a re-
   lationship where interference is virtually eliminat-
   ed (e.g. where eavesdropping cannot occur) where
   multiple receivers and transmitters occupy the
   same environment.
J.A. 15271 (emphasis added).



   3    We have often held that the meaning of claim
terms in one patent can be informed by statements made
during prosecution of other patents in the same family.
We have explained, for example, that “past and future
prosecution of related patents may be relevant to the
construction of a given claim term.” Teva Pharm. USA,
Inc. v. Sandoz, Inc., 789 F.3d 1335, 1343 n.5
(Fed. Cir. 2015).
12                                     ONE-E-WAY, INC.   v. ITC



     The parties dispute, however, the relevance of this
statement in the prosecution history. The Government
and Respondents assert that this prosecution history
statement is irrelevant to the meaning of “virtually free
from interference” because it was made by the applicant
regarding claims reciting the term “free from interfer-
ence,” rather than “virtually free from interference.”
J.A. 15271 (discussing amendments to claims 24–27 in
parent patent application 12/144,729).         Because the
prosecution history statement referred to “virtually free
from interference” and the claims referred to “free from
interference,” the ALJ found “it impossible to agree with
Complainant that one of ordinary skill in the art would
conclude that the applicant was providing guidance as to
the meaning and scope of a different limitation (i.e.,
‘virtually free from interference’).” J.A. 10.
    We conclude, however, that the person of ordinary
skill would have found this statement in the prosecution
history instructive. First, the “free from interference”
claims were not the only ones pending at the time appli-
cants filed the response. Rather, there were other pend-
ing claims reciting “virtually free from interference,”
namely already-allowed claims 12 and 16. J.A. 15296,
15329–31.
     Moreover, the very language of the prosecution histo-
ry statement employs the term “virtually.” The applicant
stated that Lavelle does not teach that “interference is
virtually eliminated (e.g. where eavesdropping cannot
occur).” J.A. 15271. On its face, this statement suggests
that interference, virtually eliminated, results in listening
without eavesdropping. As noted above, this understand-
ing is entirely consistent with the specification, which
suggests that “free from interference” provides private
listening. See ’258 patent col. 1 ll. 64–67. This under-
standing is also consistent with the testimony of
One-E-Way’s technical expert, who explained that “[t]he
concept of a user not being able to eavesdrop on the device
ONE-E-WAY, INC.   v. ITC                                   13



transmissions of another user is consistent with the
purpose (‘private listening’) and the mechanisms (separa-
tion of users by recognizing other transmissions as ‘noise’)
disclosed in the patents.” J.A. 12922 (alteration in origi-
nal) (ALJ’s order construing terms of the asserted patents
and acknowledging expert testimony).
    The context of the prosecution history does not man-
date a different reading. The examiner had rejected the
claims over Lavelle. Lavelle, according to the applicant,
did not disclose the claimed audio “free from interference.”
That might have been enough for the applicant’s amend-
ment to succeed, but the applicant appears to have made
an even bolder claim, namely that Lavelle is not even
“virtually free from interference,” let alone totally free. In
other words, Lavelle does not meet the “free from inter-
ference” claim term because it does not disclose listening
that is even virtually free.
                             C.
    Respondents further argue that the term “virtually
free from interference” does not “inform one of ordinary
skill in the art as to any particular level of interference or
as to how much interference is permitted.” Intervenors’
Br. 13. The ALJ similarly found that the term “is indefi-
nite . . . because one of ordinary skill in the art would not
be able to discern with reasonable certainty what amount
or level of interference constitutes ‘virtually free from
interference.’” J.A. 12925 (ALJ’s order construing terms
of the asserted patents). This finding was based in part
on Respondents’ assertion “that there are known ways to
define levels of interference in the ISM band, such as
signal to noise ratios, packet errors and bit rate errors,
but that the specifications give no examples or descrip-
tions and have no relevant figures relating to levels of
interference.” J.A. 12923 (ALJ’s summary of Respond-
ents’ position).
14                                    ONE-E-WAY, INC.   v. ITC



     While One-E-Way did not define the scope of the term
“virtually free from interference” in a technical sense as
both the ALJ and Respondents would seemingly require,
the lack of a technical definition does not render the term
indefinite. As demonstrated by the specification and
prosecution history discussed above, the applicant used
the term “interference” in a non-technical manner to
simply mean that the wireless headphone user is able to
listen without eavesdropping.       This interpretation is
consistent with the specification and prosecution history
and provides a clear line such that it informs those skilled
in the art about the scope of the invention with reasona-
ble certainty. For the purposes of definiteness, the term
is not required to have a technical measure of the amount
of interference.
                            D.
    Finally, we consider the Government and Respond-
ent’s claim that “virtually free from interference” must be
indefinite because One-E-Way fails to identify how it
differs in scope from claims that recite the term “free from
interference.”
    At the outset, we note that One-E-Way has not as-
serted claims that recite the term “free from interference”
here. The asserted claims recite only “virtually free from
interference.” We are aware of no precedent requiring us
to construe the “free from interference” term where, as
here, the term is absent from any asserted claim.
    Nevertheless, without deciding the meaning of the
term “free from interference,” an understanding of the
relative meaning of these terms is readily apparent. Both
terms relate, of course, to the ultimate aim of the patent-
ed invention: providing private listening without interfer-
ence from signals transmitted by other users’ wireless
audio transmission devices. E.g., ’258 patent, Abstract.
As we have explained, the claims, specification, and
prosecution history show that “virtually free from inter-
ONE-E-WAY, INC.   v. ITC                                 15



ference” means the ability to listen without eavesdropping
such that a user is not able to listen to another user’s
transmissions in the wireless digital audio system spec-
trum. When the patented system works, the listener will,
for example, hear only their music, but not that of others.
The claims recite this listening-without-eavesdropping
feature as audio “virtually free from interference.”
    Audio “free from interference” will be a bit better than
audio “virtually free from interference,” in the same way
something “free from defects” will be a bit better than
something “substantially” or “virtually free from defects.”
It follows that one of ordinary skill might expect that
because audio “virtually free from interference” is free
from eavesdropping, audio “free from interference” will be,
at a minimum, free from eavesdropping as well.
                           CONCLUSION
     We conclude that a person of ordinary skill in the art,
viewing the claim term “virtually free from interference”
in light of the specification and prosecution history, would
be informed of the scope of the invention with reasonable
certainty. While we note that “virtually” is a term of
degree, one that slightly expands the scope of the term
“free from interference,” the inclusion of “virtually” in
these claims does not render them indefinite. See Eibel
Process, 261 U.S. at 58. The term “virtually” does not
expand “free from interference” without end: it simply
requires that the claimed invention does not allow for
eavesdropping. A system that permits eavesdropping is
no longer “free” or “virtually free from interference”; that
system is no longer captured by the asserted patents’
claims. Thus, the term “virtually free from interference”
satisfies the requirements of § 112 ¶ 2.
16                                 ONE-E-WAY, INC.   v. ITC



    We reverse the Commission’s determination that the
asserted claims are indefinite and remand to the Com-
mission for further proceedings consistent with this
opinion.
             REVERSED AND REMANDED
                           COSTS
     Costs to Appellant.
  United States Court of Appeals
      for the Federal Circuit
                 ______________________

                  ONE-E-WAY, INC.,
                     Appellant

                           v.

     INTERNATIONAL TRADE COMMISSION,
                 Appellee

SONY CORPORATION, SONY CORPORATION OF
AMERICA, SONY ELECTRONICS, INC., BLUEANT
WIRELESS PTY, LTD., BLUEANT WIRELESS, INC.,
CREATIVE TECHNOLOGY LTD., CREATIVE LABS,
           INC., GN NETCOM A/S,
                  Intervenors
            ______________________

                       2016-2105
                 ______________________

   Appeal from the United States International Trade
Commission in Investigation No. 337-TA-943.
                ______________________

PROST, Chief Judge, dissenting.
    In finding that the claim limitation-at-issue—
“virtually free from interference”—meets the definiteness
requirement, the majority relies primarily, if not exclu-
sively, on a single, non-definitional remark from the
prosecution history and ignores intrinsic evidence that
injects ambiguity. The written description lacks any
reference to the disputed limitation. And One-E-Way
2                                      ONE-E-WAY, INC.   v. ITC



does not submit that the limitation-at-issue has any
ordinary meaning to a skilled artisan.
    By relying so heavily on the cherry-picked prosecution
remark, the majority’s decision significantly relaxes the
law on indefiniteness against the tide of the Supreme
Court’s recent decision in Nautilus, Inc. v. Biosig Instru-
ments, Inc., 134 S. Ct. 2120 (2014). It also flouts the well-
established principle that “the written description is key
to determining whether a term of degree is indefinite.”
Sonix Tech. Co. v. Publ’ns Int’l, Ltd., 844 F.3d 1370, 1378
(Fed. Cir. 2017). Even if it may be possible to “ascribe
some meaning” to the disputed limitation, the Supreme
Court has held that more is required. Nautilus, 134 S. Ct.
at 2130. Here, the intrinsic evidence falls well short of
providing a skilled artisan “reasonable certainty” about
the metes and bounds of the disputed limitation, especial-
ly as distinguished from the narrower limitation “free
from interference” (without the modifier “virtually”). Id.
at 2124.
    I therefore respectfully dissent from the majority’s
conclusion reversing the Commission’s indefiniteness
determination.
                              I
    Under the definiteness requirement, a patent appli-
cant must conclude the specification with “one or more
claims particularly pointing out and distinctly claiming
the subject matter which the applicant regards as his
invention.” 1 35 U.S.C. § 112, ¶ 2. The Supreme Court



    1   The language of 35 U.S.C. § 112, ¶ 2 was replaced
with § 112(b) by § 4(c) of the America Invents Act (“AIA”),
and § 4(e) makes that change applicable “to any patent
application that is filed on or after” September 16, 2012.
Pub. L. No. 112-29, § 4, 125 Stat. at 296–97. Because the
ONE-E-WAY, INC.   v. ITC                                  3



has explained that this requirement serves an important
notice function, ensuring that a patent “appris[es] the
public of what is still open to them.” Nautilus, 134 S. Ct.
at 2129 (quoting Markman v. Westview Instruments, Inc.,
517 U.S. 370, 373 (1996)). It should also serve as a
“meaningful . . . check” against “foster[ing] [an] innova-
tion-discouraging ‘zone of uncertainty.’” Id. at 2129–30
(quoting United Carbon Co. v. Binney & Smith Co., 317
U.S. 228, 236 (1942)). In resolving the level of precision
required, the Supreme Court held that patent claims are
invalid for indefiniteness if, when read in light of the
specification and the prosecution history, they “fail to
inform, with reasonable certainty, those skilled in the art
about the scope of the invention.” Id. at 2124.
    The parties agree that “virtually free from interfer-
ence” is a “term of degree.” Appellant’s Opening Br. 11;
Government’s Br. 19; Respondents’ Br. 13. 2 Terms of
degree are not “inherently indefinite,” and “absolute or
mathematical precision is not required.” Interval Licens-
ing LLC v. AOL, Inc., 766 F.3d 1364, 1370 (Fed. Cir.
2014). Nevertheless, the claims, read in context “must
provide objective boundaries for those of skill in the art.”
Id. at 1371 (citing Nautilus, 134 S. Ct. at 2130 & n.8).
“[P]ast and future prosecution of related patents may be
relevant to the construction of a given claim term.” Teva
Pharm. USA, Inc. v. Sandoz, Inc., 789 F.3d 1335, 1343 n.5
(Fed. Cir. 2015). But as noted above, the written descrip-
tion is “key” to the indefiniteness inquiry for a term of
degree. Sonix, 844 F.3d at 1378; see also Liberty Ammu-
nition, Inc. v. United States, 835 F.3d 1388, 1395 (Fed.



applications resulting in the patents-at-issue were filed
before that date, the pre-AIA version of § 112 applies.
    2   Following the majority’s convention, I refer to the
Commission as the “Government” when referring to its
role as a party on appeal.
4                                     ONE-E-WAY, INC.   v. ITC



Cir. 2016) (“[T]he specification is the single best guide to
the meaning of a disputed term and usually, it is disposi-
tive.” (alteration and internal quotation marks omitted)).
    One-E-Way did not submit any extrinsic evidence to
argue that “virtually free from interference” has any
ordinary meaning to a person of ordinary skill in the art.
The indefiniteness inquiry therefore rests on the intrinsic
evidence.
                             A
    One-E-Way relies heavily on a single statement made
during prosecution of U.S. Patent No. 7,684,885 (“’885
patent”), which shares a common specification with the
patents-at-issue. Specifically, in traversing a rejection,
the patentee stated that the prior art “does not teach,
disclose, or suggest . . . a relationship where interference
is virtually eliminated (e.g. where eavesdropping cannot
occur) where multiple receivers and transmitters occupy
the same environment.” J.A. 15271 (emphasis added).
One-E-Way submits that this remark “inform[s]” a person
of ordinary skill that “virtually free from interference”
refers to “no eavesdropping.” Appellant’s Opening Br. 9,
15. The Government and Respondents argue that the
remark is entirely irrelevant because it related to claims
that do not recite the “virtually free from interference”
limitation.
    For the reasons explained by the majority (and con-
trary to the Commission’s decision), I agree that the
prosecution history statement, read in context, is relevant
to the meaning of “virtually free from interference.” But I
disagree that it, alone or with the rest of the intrinsic
evidence, informs with the reasonable certainty needed to
satisfy the definiteness requirement.
    One-E-Way concedes that the patentee was not acting
as his own lexicographer to define “virtually free from
interference” to mean “no eavesdropping.” Oral Argu-
ONE-E-WAY, INC.   v. ITC                                    5



ment 9:08–9:41, http://oralarguments.cafc.uscourts.gov/
mp3/2016-2105.mp3.        Indeed, One-E-Way originally
proposed construing “virtually free from interference” to
mean “for practical purposes free from extraneous energy
artifacts impeding the desired signal.” J.A. 11252. By
doing so, One-E-Way implicitly recognized that “no eaves-
dropping” is not the only way that a skilled artisan might
understand the disputed limitation in view of the intrinsic
evidence. It was not until the Government argued that
the term is indefinite that One-E-Way changed its pro-
posed construction to rely on the statement from the
prosecution history. See J.A. 11269–71. That statement
is the only place in the intrinsic evidence where the
concept of “eavesdropping” ever appears.         Therefore,
though the majority dresses up its analysis with refer-
ences to the claims and specification, its conclusion that
the disputed limitation “means the ability to listen with-
out eavesdropping,” Majority Op. 15, necessarily hinges
on the prosecution history statement.
    One-E-Way acknowledges that the prosecution state-
ment provides “no eavesdropping” merely as an example
of when “virtually free from interference” might be satis-
fied. Oral Argument 10:47–11:54. As Respondents argue,
the use of “e.g.” in the prosecution statement supports
that reading. But merely “identify[ing] some standard for
measuring the scope of [a] phrase” is not sufficient.
Interval Licensing, 766 F.3d at 1373 (internal quotation
marks omitted). The majority runs afoul of the Supreme
Court’s warning against “viewing matters post hoc” to
“ascribe some meaning to a patent’s claims.” Nautilus,
134 S. Ct. at 2130; cf. Interval Licensing, 766 F.3d at 1374
(stating that it is inappropriate to “cull out a single ‘e.g.’
phrase from a lengthy written description to serve as the
exclusive definition of a facially subjective claim term”).
    To be sure, we have held a term to be definite where it
is defined through specific examples in the written de-
scription or where an expert opines on the guidance of a
6                                      ONE-E-WAY, INC.   v. ITC



detailed embodiment provided in the written description.
See, e.g., Mentor Graphics Corp. v. EVE-USA, Inc., 851
F.3d 1275, 1293 (Fed. Cir. 2017) (relying on figures and
examples in the specification); Apple Inc. v. Samsung
Elecs. Co., 786 F.3d 983, 1002 (Fed. Cir. 2015), rev’d and
remanded on other grounds, 137 S. Ct. 429 (2016) (relying
on expert’s explanation of an illustrated embodiment).
Neither scenario, however, is before us. One-E-Way has
not cited any cases finding a term to be definite based on
a single example in the prosecution history of a related
patent. I would decline to do so here.
                             B
     One-E-Way also relies on the prosecution history of
another related patent, U.S. Patent No. 9,107,000 (“’000
patent”), to support its construction of “virtually free from
interference.” The majority does not include this portion
of the prosecution history in its analysis. Perhaps that is
because this part of the intrinsic evidence injects ambigui-
ty, rather than clarity, into the disputed limitation.
      During examination of the ’000 patent, the examiner
stated: “[T]he CDMA implementation of the combination
requires a device be paired to a particular ‘code,’ which is
the entire basis of CDMA. This code enables transmission
and reception separate from other CDMA transmission,
i.e. ‘virtually free from interference.’” J.A. 5962 (emphasis
added). One-E-Way argues that the examiner apparently
had no trouble understanding the meaning of the disput-
ed limitation. It relies on this court’s recent holding in
Sonix that an examiner’s understanding of a claim term
“provide[s] evidence that a skilled artisan did understand
the scope of th[e] invention with reasonable certainty.”
844 F.3d at 1380.
    But as the Government and Respondents correctly ob-
serve, that decision expressly noted that “application by
[an] examiner . . . do[es] not, on [its] own, establish an
objective standard.” Id. Rather, in Sonix, this court
ONE-E-WAY, INC.   v. ITC                                    7



relied primarily on written description support. Id. at
1378–79 (concluding that the written description provided
sufficient level of detail). As explained below, such sup-
port is absent in this case.
    Furthermore, the examiner’s statement does not refer
to eavesdropping, only to separating transmissions. It is
not clear how separating transmissions is related, if at all,
to no eavesdropping. One-E-Way does not argue that
those two concepts are synonymous, only that they are
“consistent.” Appellant’s Opening Br. 21. But even
assuming they are consistent, there is no indication that a
person of ordinary skill would know which concept is
being used to define “virtually free from interference.”
    The examiner’s statement during prosecution of the
’000 patent therefore fails to demonstrate definiteness or
advance One-E-Way’s “no eavesdropping” construction. If
anything, the examiner’s statement adds uncertainty to
the scope of “virtually free from interference” and sup-
ports a determination of indefiniteness.
                              II
     The majority purports to also rely on the common
specification of the patents-at-issue to bolster its definite-
ness conclusion. That specification, however, does not
explain, explicitly or implicitly, the limitation “virtually
free from interference.” Instead, it discusses “private
listening without interference from other users or wireless
devices.” ’258 patent col. 1 l. 65 (emphasis added). 3




    3  For consistency with the majority opinion, I cite to
the ’258 patent when discussing the common specifica-
tion.
8                                          ONE-E-WAY, INC.   v. ITC



                                A
    Notably, One-E-Way does not argue that the specifi-
cation discloses any definition or specific embodiments of
“virtually free from interference.” Instead, One-E-Way
argues in the negative that nothing in the specification
“provide[s] a contrary or inconsistent indication” to the
prosecution history remark regarding “no eavesdropping.”
Appellant’s Opening Br. 14. For example, One-E-Way
contends that the specification’s use of “without interfer-
ence” allows for some interference—i.e., it does not re-
quire zero interference—but stops short of saying that
“without interference” is synonymous with “virtually free
from interference.” 4 Id. at 23.
    The phrase “without interference” is an absolute term
like the phrase “free from interference” (without the
modifier “virtually”) that appears in non-asserted claims.
See, e.g., ’885 patent col. 6 ll. 44–45, col. 8 ll. 4–5, col. 8 ll.
29–31. Adding the modifier “virtually” provides some
degree of broadening that is not captured, on its face, by
the phrase “without interference.” Therefore, under a
plain reading, the written description’s discussion of
“without interference” maps onto the limitation “free from
interference,” not the disputed limitation.




    4   At oral argument, One-E-Way submitted for the
first time that “without interference” means “virtually
free from interference.” Oral Argument 6:50–7:27. That
argument is waived for not being developed in the open-
ing brief. See SmithKline Beecham Corp. v. Apotex Corp.,
439 F.3d 1312, 1319 (Fed. Cir. 2006) (“Our law is well
established that arguments not raised in the opening brief
are waived.”). Even if it were not waived, I find this
argument—which even the majority does not adopt—
unpersuasive for the reasons discussed.
ONE-E-WAY, INC.   v. ITC                                    9



     The majority relies on the phrase “private listening”
from the written description, which it asserts is “entirely
consistent” with the concept of “no eavesdropping” men-
tioned during prosecution. Majority Op. 12. But the
specification’s discussion of “private listening” only relates
to “without interference,” which is not the same as “virtu-
ally free from interference.” When pressed at oral argu-
ment, One-E-Way itself declined to equate “private
listening” with “no eavesdropping,” only going as far as to
say that they can “coexist.” Oral Argument 15:41–18:01;
see also Appellant’s Opening Br. 10 (asserting vaguely
that “private listening and eavesdropping go hand-in-
hand”). Just as it is unclear how the concept of separat-
ing transmissions is related to eavesdropping, it is also
unclear how the concept of private listening is related to
eavesdropping.
    Therefore, the written description’s discussion of
“without interference” and “private listening” do not
inform the scope of “virtually free from interference.”
                              B
    Furthermore, the majority fails to construe the mean-
ing of the modifier “virtually,” which undisputedly broad-
ens the scope of the phrase “free from interference.” That
is because the intrinsic evidence lacks any such disclo-
sure.
    Even if we need not separately construe “free from in-
terference,” we cannot ignore its relevance to the inquiry
before us. Cf. Merck & Co. v. Teva Pharm. USA, Inc., 395
F.3d 1364, 1372 (Fed. Cir. 2005) (“A claim construction
that gives meaning to all the terms of the claim is pre-
ferred over one that does not do so.”). Adding the modifier
“virtually” provides the quintessential wiggle room to
reach some audio transmissions that are not strictly “free
from interference.” And One-E-Way concedes that under
the doctrine of claim differentiation, “virtually” must
carry significance in this context. See Appellant’s Open-
10                                          ONE-E-WAY, INC.   v. ITC



ing Br. 8, 17; Oral Argument 1:58–2:09. Yet, as discussed
above, the written description only delineates the claimed
invention in terms of audio free from interference. The
use of “virtually” in the claim language is therefore nebu-
lous and does not indicate how much more interference is
acceptable to satisfy the disputed limitation.
     The majority makes no attempt to construe the import
of the word “virtually.” The closest it gets to clarity is to
characterize audio that is “free from interference” as
being “a bit better” than audio that is “virtually free from
interference.” Majority Op. 15. To be sure, One-E-Way
relies on the specification’s reference to a technique called
“fuzzy logic detection” to argue that the written descrip-
tion is not limited to audio with strictly zero interference.
See ’258 patent col. 3 ll. 32–35. Even if that is true,
however, One-E-Way does not submit that the use of
fuzzy logic detection distinguishes audio “virtually free
from interference” and audio “free from interference.”
Indeed, it cannot be the point of distinction because the
’885 patent includes claims that recite the use of fuzzy
logic detection for both levels of interference. See, e.g.,
’885 patent col. 6 l. 60–col. 7 l. 7, col. 7 l. 57–col. 8 l. 7, col.
8 ll. 21–38.
    Therefore, nothing in the intrinsic evidence clarifies
the degree of broadening attached to the word “virtually”
or provides a skilled artisan with reasonable certainty
about the objective boundaries of the disputed limitation.
                                III
    I recognize that modifiers like “virtually” are some-
times used in claim limitations to provide some leeway in
scope. But a skilled artisan reviewing the patents-at-
issue must still be able to determine the objective bounda-
ries of the limitation with reasonable certainty. Nautilus,
134 S. Ct. at 2124. Here, the intrinsic evidence, at best,
mentions one example for determining when audio is
“virtually free from interference,” and that example only
ONE-E-WAY, INC.   v. ITC                                 11



appears in a single “e.g.” remark from the prosecution
history of a related patent. Viewed alongside the remain-
der of the intrinsic evidence, which either remains silent
or injects ambiguity, there is simply not enough for a
person of ordinary skill to determine the boundaries of the
limitation, much less the import of the word “virtually.”
The majority’s effort to attribute some meaning to the
disputed limitation falls far short of the level of clarity
required by the Supreme Court under Nautilus and skirts
the public-notice function of the definiteness requirement.
    I would thus affirm the Commission’s determination
that the claim limitation “virtually free from interference”
is indefinite. For the foregoing reasons, I respectfully
dissent.
