Koninklijke Philips N v. v. Zoll Medical Corporation ( 2016 )


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  •        NOTE: This disposition is nonprecedential.
    United States Court of Appeals
    for the Federal Circuit
    ______________________
    KONINKLIJKE PHILIPS N.V., PHILIPS
    ELECTRONICS NORTH AMERICA
    CORPORATION,
    Plaintiffs-Appellants
    v.
    ZOLL MEDICAL CORPORATION,
    Defendant-Cross-Appellant
    ______________________
    2014-1764, 2014-1791
    ______________________
    Appeals from the United States District Court for the
    District of Massachusetts in No. 1:10-cv-11041-NMG,
    Judge Nathaniel M. Gorton.
    ______________________
    Decided: July 28, 2016
    ______________________
    J. MICHAEL JAKES, Finnegan, Henderson, Farabow,
    Garrett & Dunner, LLP, Washington, DC, argued for
    plaintiffs-appellants. Also represented by KATHLEEN
    DALEY, LUKE MCCAMMON, DAVID MROZ, JASON LEE
    ROMRELL, ROBERT SHAFFER, SUSAN TULL.
    DAVID ISAAC GINDLER, Irell & Manella LLP, Los Ange-
    les, CA, argued for defendant-cross-appellant. Also repre-
    2                                KONINKLIJKE PHILIPS N.V. v.
    ZOLL MEDICAL CORPORATION
    sented by ALAN J. HEINRICH; DAVID C. MCPHIE, Newport
    Beach, CA.
    ______________________
    Before LOURIE, DYK, and HUGHES, Circuit Judges.
    HUGHES, Circuit Judge.
    Philips sued Zoll for infringement of numerous pa-
    tents related to external defibrillators. Zoll counter-
    claimed for infringement of its own patents covering
    related technology. The parties presented their cases to a
    jury, which found, among other things, that both parties’
    patents are not invalid, both parties directly infringe the
    asserted patents, but Zoll does not contributorily infringe
    the asserted Philips patents. The district court denied all
    motions for judgment as a matter of law, and both parties
    appeal these denials. For the reasons set forth below, we
    affirm-in-part, reverse-in-part, and vacate-in-part the
    district court’s judgment. We remand the case for further
    proceedings.
    I. BACKGROUND
    Philips and Zoll both manufacture and sell external
    defibrillators. Defibrillators are electronic devices that
    apply an electrical shock to a person’s heart for therapeu-
    tic purposes. Defibrillators are commonly used to treat
    ventricular fibrillation, which occurs when the muscle
    fibers of a person’s heart contract without coordination.
    Application of an electrical shock interrupts the irregular
    contractions, allowing the heart to return to its normal
    rhythm of contraction.
    “External” defibrillators are defibrillators that are not
    implanted in a person’s body. Because they are provided
    outside of the person’s body, external defibrillators must
    deliver the electrical shock indirectly, as applied to the
    surface of the person’s skin. In addition, because the
    electrical shock must pass through the person’s skin and
    KONINKLIJKE PHILIPS N.V. v.                                 3
    ZOLL MEDICAL CORPORATION
    thorax before reaching the person’s heart, external defib-
    rillators generally need to operate at higher voltages
    and/or currents than implanted defibrillators.
    This application of high levels of electricity to the sur-
    face of a person’s skin to treat a time-sensitive medical
    condition introduces numerous challenges, which the
    patents-in-suit address.
    A. Waveform Patents
    Philips asserted a first group of patents that we will
    refer to as the “waveform” patents. These are: U.S.
    Patent 5,607,454; U.S. Patent 5,749,905; and U.S. Patent
    6,047,212.
    In the most general sense, the waveform patents are
    directed to controlling the waveform of the electrical
    shock that is delivered to a subject person’s body. The
    waveform patents explain that one challenge with exter-
    nal defibrillators is that of subject variability. With
    implanted defibrillators, only a single person is ever the
    subject of the device, so the device can be precisely tuned
    to deliver the ideal electrical shock to that subject. But an
    external defibrillator may be used on multiple subjects,
    each with a distinct body composition. The differences
    between different subjects’ hearts, the differences be-
    tween the electrical impedance created by different sub-
    jects’ thoraxes, and other body composition differences
    mean that an ideal external defibrillator would be capable
    of providing different electrical shocks. But configuring
    the various parameters of the electrical shock, e.g., the
    initial voltage and duration of the initial voltage phase,
    can be a complicated technique that typically can only be
    executed by a trained professional.
    The waveform patents aim to address this challenge
    by providing an external defibrillator that can automati-
    cally vary the electrical shock based on the body composi-
    tion of the subject, eliminating the need for a trained
    4                                 KONINKLIJKE PHILIPS N.V. v.
    ZOLL MEDICAL CORPORATION
    operator. See ’454 patent, col. 3 ll. 37–40. The waveform
    patents disclose that an external defibrillator can be
    configured to detect an “electrical parameter” of the
    subject, such as the electrical impedance of the subject’s
    thorax, and then adjust the electrical shock based on this
    monitored electrical parameter. See 
    id. at col.
    3 ll. 44–53.
    Philips asserted the following claims of the waveform
    patents against Zoll: ’454 patent claim 51; ’905 patent
    claims 4 and 8; and ’212 patent claims 1 and 5. See J.A.
    108–11.
    B. Self-Test Patents
    Philips asserted a second group of patents that we
    will refer to as the “self-test” patents. These are: U.S.
    Patent 5,800,460 and U.S. Patent 5,879,374.
    The self-test patents are directed to an external defib-
    rillator’s capability to test its own functional status with-
    out human intervention. External defibrillators prior to
    the self-test patents tended to be deployed in high-usage
    environments, such as a hospital emergency room, where
    they could be tested regularly to ensure their operability.
    But in low-usage environments, such as an emergency
    medical vehicle or in a stationary deployment in an office
    building, regular testing was inconvenient.
    The self-test patents aim to address this challenge by
    providing a self-testing capability within an external
    defibrillator. See ’460 patent, col. 1 ll. 44–48. The self-
    testing capability allows the external defibrillator to
    periodically, e.g., once per day, test the functionality of its
    components, e.g., that its battery is sufficiently charged.
    See 
    id. at col.
    1 ll. 38–48. The external defibrillator
    provides a visual and/or audible indicator of the self-test
    results. See 
    id. at Abstract.
        Philips asserted the following claims of the self-test
    patents against Zoll: ’460 patent claim 7; and ’374 patent
    claims 42–43 and 67–68. See J.A. 105–06.
    KONINKLIJKE PHILIPS N.V. v.                                5
    ZOLL MEDICAL CORPORATION
    C. Electrode Patent
    Zoll asserted U.S. Patent 5,330,526, which is directed
    to an electrode for use with an external defibrillator.
    Prior to the ’526 patent, it was common practice to
    provide an electrolytic gel on the surface of the electrodes
    of an external defibrillator. After soaking into the sub-
    ject’s skin, the electrolytes in the gel would provide a
    conducting path from the electrodes through the outer
    surface of the subject’s skin. This allowed the electrical
    shock to easily pass into the subject’s body instead of
    dissipating on the surface of the subject’s skin. It was
    common to provide the electrodes and electrolytic gel to
    have an electrical resistance of less than 1 ohm, thereby
    heightening this conductivity factor.
    The ’526 patent discloses that this very low resistance
    characteristic of the electrode and electrolytic gel can
    actually be disadvantageous. In particular, use of very
    low resistance electrodes and electrolytic gel demonstrat-
    ed that some burning occurs on the subject’s skin at the
    outer edge of the electrolytic gel. See ’526 patent, col. 1
    l. 57–col. 2 l. 7. As a result, the ’526 patent discloses
    various configurations of the electrode and electrolytic gel,
    each configuration having an electrical resistance of at
    least 1 ohm. See 
    id. at col.
    2 ll. 16–49.
    Zoll asserted claims 1, 8–9, 11–12, 19, and 24–25 of
    the ’526 patent against Philips. See J.A. 115.
    D. District Court Proceedings
    The district court submitted various issues of in-
    fringement and validity to a jury, but bifurcated all dam-
    6                                KONINKLIJKE PHILIPS N.V. v.
    ZOLL MEDICAL CORPORATION
    ages issues for a later trial. The jury made the following
    determinations. 1
    First, the jury found each of the following claims of
    the waveform and self-test patents not invalid: ’454
    patent claim 51; ’905 patent claims 4 and 8; ’460 patent
    claim 7; and ’374 patent claims 42–43 and 67–68. See J.A.
    112–13.
    Second, the jury found that Zoll directly infringed
    each of the following claims of the waveform and self-test
    patents with at least one of its products: ’454 patent
    claim 51; ’905 patent claims 4 and 8; ’212 patent claims 1
    and 5; ’460 patent claim 7; and ’374 patent claims 42–43
    and 67–68. See J.A. 105–11.
    Third, the jury found that Zoll had neither contributo-
    rily nor inducedly infringed any of the following claims of
    the waveform and self-test patents with any of its prod-
    ucts: ’454 patent claim 51; ’905 patent claims 4 and 8;
    ’460 patent claim 7; and ’374 patent claims 42–43 and 67–
    68. See J.A. 105–11.
    Fourth, the jury found that Philips directly infringed
    each of the following claims of the ’526 patent with at
    least one of its products: claims 1, 8–9, 11–12, 19, and
    24–25. See J.A. 115. The jury further found that each of
    these claims was not invalid. See J.A. 116.
    Philips and Zoll moved for judgment as a matter of
    law on each of the foregoing grounds on which it did not
    prevail. The district court summarily denied JMOL
    without discussion.
    1  The jury made findings on several other issues
    presented by Philips and Zoll. See J.A. 104–16. Because
    the parties do not appeal those additional issues, we do
    not address them further in this opinion.
    KONINKLIJKE PHILIPS N.V. v.                              7
    ZOLL MEDICAL CORPORATION
    Philips and Zoll appeal those denials. We have juris-
    diction under 28 U.S.C. § 1292(c)(2). See Robert Bosch,
    LLC v. Pylon Mfg. Corp., 
    719 F.3d 1305
    , 1317 (Fed. Cir.
    2013) (en banc).
    II. STANDARD OF REVIEW
    This court reviews denial of a JMOL motion according
    to the law of the regional circuit. Am. Calcar, Inc. v. Am.
    Honda Motor Co., 
    651 F.3d 1318
    , 1341 (Fed. Cir. 2011).
    The First Circuit reviews the grant or denial of JMOL de
    novo. See Soto-Lebron v. Fed. Express Corp., 
    538 F.3d 45
    ,
    56 (1st Cir. 2008). “Courts may only grant a judgment
    contravening a jury’s determination when the evidence
    points so strongly and overwhelmingly in favor of the
    moving party that no reasonable jury could have returned
    a verdict adverse to that party.” Marcano Rivera v.
    Turabo Med. Ctr. P’ship, 
    415 F.3d 162
    , 167 (1st Cir. 2005)
    (internal quotation marks omitted).
    We address Philips’s and Zoll’s arguments in the fol-
    lowing order. First, we address Zoll’s cross-appeal as to
    invalidity and direct infringement of the waveform and
    self-test patents in parts III. and IV., respectively. Sec-
    ond, we address Philips’s appeal as to indirect infringe-
    ment of the waveform and self-test patents in part V.
    Third, we address Philips’s appeal as to indefiniteness of
    the electrode patent in part VI. Finally, we address
    Philips’s appeal as to the admission of evidence in part
    VII.
    III. INVALIDITY OF WAVEFORM AND
    SELF-TEST CLAIMS
    The jury found claims of Philips’s waveform and self-
    test patents not invalid over various prior art references.
    Zoll contests these verdicts as discussed below.
    8                                KONINKLIJKE PHILIPS N.V. v.
    ZOLL MEDICAL CORPORATION
    A. Waveform Claims
    The jury found that claims 4 and 8 of the waveform
    ’905 patent were not anticipated by U.S. Patent 5,432,686
    (Kroll). Claim 4 recites the following:
    A method for delivering electrotherapy to a
    patient through electrodes connected to an energy
    source, the method comprising the following steps:
    discharging the energy source across the elec-
    trodes to deliver electrical energy to the patient in
    a multiphasic waveform;
    monitoring a patient-dependent parameter
    during the discharging step;
    shaping the waveform so that an initial pa-
    rameter of a waveform phase depends on a value
    of the electrical parameter.
    Claim 8 is dependent on claim 4. Anticipation is a ques-
    tion of fact, ArcelorMittal France v. AK Steel Corp., 
    700 F.3d 1314
    , 1322 (Fed. Cir. 2012), and we will overturn the
    jury’s verdict only if “the evidence points so strongly and
    overwhelmingly in favor” of anticipation that “no reason-
    able jury could have returned” the jury’s verdict of no
    anticipation, Marcano 
    Rivera, 415 F.3d at 167
    . Zoll
    argues that no reasonable jury could conclude that Kroll
    fails to disclose each of the features of claim 4. We disa-
    gree.
    Kroll discloses a method for delivering electrotherapy
    to a subject. The method illustrated in Figure 7 of Kroll
    includes a step 94 of beginning delivery of energy from a
    capacitor into the subject’s body, a step 96 of waiting for
    the capacitor discharge voltage to decay a “given percent-
    age,” and a step 104 of continuing to discharge energy
    from the capacitor but with a reversed polarity. See Kroll,
    KONINKLIJKE PHILIPS N.V. v.                               9
    ZOLL MEDICAL CORPORATION
    Fig. 7, col. 9 ll. 46–68. This is further illustrated in the
    marked up Figure 2 of Kroll shown below: 2
    As shown, discharging of the energy across the subject’s
    body begins at some starting voltage (step 94), discharg-
    ing continues until some predefined “given percentage” of
    the starting voltage has been dissipated (step 96), and
    then the polarity of the voltage is reversed and the dis-
    charging of the energy continues (step 104). The initial
    discharging of the energy constitutes a first phase of
    discharge 32, while the reverse-polarity discharge of the
    energy constitutes a second phase of discharge 34.
    Kroll suggests that the “given percentage” that trig-
    gers the end of the first phase of discharge is optimally
    44% of the starting voltage level. See Kroll, col. 9 ll. 55–
    2   Our markup includes the Y axis label for “volt-
    age,” the labeling of the “first phase” and “second phase,”
    and the labeling of the steps 94, 96, and 104.
    10                               KONINKLIJKE PHILIPS N.V. v.
    ZOLL MEDICAL CORPORATION
    58. Importantly, the “given percentage” is a value calcu-
    lated from mathematical equations of physiology, which
    are not specific to the subject being treated during execu-
    tion of the method. See Kroll, Abstract, col. 6 ll. 16–40.
    It is indisputable that Kroll discloses the “discharg-
    ing” step of claim 4. The question is whether Kroll moni-
    tors a “patient-dependent parameter” and then “shap[es]
    the waveform so that an initial parameter of a waveform
    phase” is based on that “patient-dependent parameter.”
    In some sense, the voltage being dissipated into the
    subject’s body in Kroll is a “patient-dependent parame-
    ter.” When the method of Kroll is performed, the subject’s
    body forms part of a closed circuit that is arranged in the
    following series: the defibrillator (which sets the current
    and has an inherent electrical resistance); the first elec-
    trode; the patient’s body (which has a subject-specific
    electrical resistance as discussed previously); the second
    electrode; and back to the defibrillator. Because voltage
    and resistance are directly related to one another by
    Ohm’s law—voltage = current × resistance—and because
    the current is fixed by the defibrillator, the voltage dissi-
    pating into the subject’s body is at least in part dependent
    on the patient’s own particular electrical resistance.
    Thus, the dissipating voltage in Kroll might be considered
    a “patient-dependent parameter.” And because the meth-
    od of Kroll requires observing the dissipating voltage level
    so as to stop dissipation when it reaches the “given per-
    centage,” Kroll arguably discloses the “monitoring” step of
    claim 4.
    It is less clear that Kroll discloses the “shaping” step
    of claim 4. The Kroll method stops dissipation in the first
    phase at 44% of the starting voltage, and the method then
    begins dissipation in the second phase at that same
    voltage level (with the current flowing in the opposite
    direction). Therefore, Zoll argues, voltage is a “patient-
    dependent parameter,” and because the initial voltage
    KONINKLIJKE PHILIPS N.V. v.                               11
    ZOLL MEDICAL CORPORATION
    level of the second phase of dissipation is based on a
    percentage value of that parameter, Kroll discloses the
    “shaping” step of claim 4.
    But that incorrectly describes what occurs in the Kroll
    method. In Kroll, the first phase of dissipation always
    ends at 44% (or some other predetermined “given per-
    centage”) of the starting voltage of the first phase. Nei-
    ther the 44% value nor the starting voltage is dependent
    on the subject being treated. See Kroll, col. 4–6. Rather,
    these characteristics are computed absent a patient-
    specific resistance value. See 
    id. at col.
    6 ll. 41–46.
    Therefore, the starting voltage and the ending voltage of
    the first phase are not dependent on the subject being
    treated. Because the starting voltage of the second phase
    is the same as the ending voltage of the first phase, it too
    does not depend on the subject being treated. So, the
    subject-specific electrical resistance does not change the
    starting or ending amplitudes of the waveform. Instead,
    it will affect how quickly the voltage dissipates, essential-
    ly shortening or lengthening the time of the first phase
    and the second phase (the x-axis in Figure 2 of Kroll).
    Thus Kroll discloses fixed, non-subject-specific start-
    ing and ending voltages for the waveform, and incidental-
    ly the waveform may be compressed or stretched in time
    in a patient-dependent way. The parties did not dispute
    the meaning of “shaping the waveform,” and the district
    court did not expressly construe this language. J.A. 101–
    03. Whether Kroll’s method discloses the “shaping” step
    of claim 4 is a factual question left to the jury for resolu-
    tion based on the ordinary meaning of the claims. Both
    Philips and Zoll presented expert evidence to explain why
    this incidental compressing/stretching of the waveform is
    or is not sufficient disclosure of the “shaping” step of
    claim 4. The jury found that it is not, and Philips’s evi-
    dence in support thereof is sufficient for a reasonable jury
    to reach the same conclusion. See J.A. 5046–50. Because
    12                                KONINKLIJKE PHILIPS N.V. v.
    ZOLL MEDICAL CORPORATION
    claim 8 depends on claim 4, the evidence is also sufficient
    to support the verdict of no anticipation for claim 8.
    Therefore, we affirm the district court’s denial of
    JMOL of invalidity as to claims 4 and 8 of the waveform
    ’905 patent.
    B. Claim 7 of the ’460 Self-Test Patent
    The jury found that claim 7 of the self-test ’460 patent
    was not anticipated by U.S. Patent 5,579,234 (Wiley).
    Claim 7, including its dependencies on claims 1, 5, and 6,
    recites the following:
    A method of performing a self-test in an ex-
    ternal defibrillator, the method comprising the fol-
    lowing steps:
    generating a test signal automatically;
    turning on a power system within the external
    defibrillator in response to the test signal; and
    performing a plurality of automatic self-tests
    within the external defibrillator for determining
    the status of the defibrillator;
    wherein the performing step comprises per-
    forming said plurality of automatic self-tests with-
    in the external defibrillator on a schedule;
    wherein the performing step comprises per-
    forming a first automatic self-test on a first peri-
    odic schedule;
    wherein the performing step comprises per-
    forming a second automatic self-test on a second
    periodic schedule.
    Zoll argues that no reasonable jury could conclude that
    Wiley fails to disclose each of these features. We agree.
    Wiley discloses various methods for automatically
    testing an electronic device during periods of non-use. See
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    ZOLL MEDICAL CORPORATION
    Wiley, Abstract. As relevant here, Wiley discloses with
    respect to Figure 4A a method of testing an electronic
    device that includes both an hourly power-on at step 210
    and a daily “autotest” at step 236. See Wiley, Fig. 4A,
    col. 6 ll. 21–30, col. 7 ll. 25–43. The device powers itself
    on every hour to perform a “CPU Test” at step 210. See
    
    id. at Fig.
    4A, col. 6, ll. 21–31, col. 7 ll. 14–24. During this
    hourly “CPU Test,” “the CPU performs its standard
    power-up self-tests internal to the particular type of CPU”
    at step 210. 
    Id. at col.
    6 ll. 21–23. The device then checks
    if it is the proper time of day to perform the daily “au-
    totest.” See 
    id. at col.
    7 ll. 14–17. If so, then the device
    (once daily) “begins a series of primary autotest functions
    236,” which can include testing whether various memory
    resources and specialized microprocessors are working
    properly. 
    Id. at col.
    7 l. 32–col. 8 l. 11.
    Therefore, Wiley on its face discloses both the “first
    automatic self-test on a first periodic schedule”—the
    hourly CPU test—and the “second automatic self-test on a
    second periodic schedule”—the more extensive daily
    “autotest”—of claim 7. Philips counters that the hourly
    “CPU test” is not an automatic self-test at all, but rather
    a sort of precursor for determining whether the daily
    “autotest” can be performed. See Philips Reply Br. 48–49.
    But it is undeniable that both the hourly test and the
    daily test are automatic, periodic, self-tests by the device.
    The only evidence that Philips presented to the contrary
    was the following exchange between Philips’s attorney
    and its expert witness:
    Q: . . . But can we also discuss [Wiley] with re-
    spect to what it doesn’t show?
    A: It does not show at all the second periodic self-
    test on the second periodic schedule.
    Q: Is that because it only has a single periodic
    schedule?
    14                                KONINKLIJKE PHILIPS N.V. v.
    ZOLL MEDICAL CORPORATION
    A: That’s right. There’s only one schedule 24
    hours and multiple tests conducted on this one
    schedule.
    J.A. 5095. This amounts to nothing more than Philips’s
    expert plainly claiming that the hourly “CPU Test” does
    not exist, even though it unmistakably does. Philips
    points to nowhere in the trial record where it presented to
    the jury its presently proffered theory that the “CPU
    Test” is somehow not a test but rather a precursor to a
    test. In contrast, Zoll did present the jury with an expla-
    nation of both the hourly and daily self-tests in the Wiley
    disclosure. See J.A. 2858–59.
    Therefore, the evidence overwhelmingly favors the
    conclusion that Wiley discloses both of the self-tests
    recited in claim 7. Wiley describes two periodic, automat-
    ic self-tests, and Zoll’s expert explained this to the jury in
    clear terms. Philips’s only rebuttal was a factually incor-
    rect, conclusory statement by its expert witness. See, e.g.,
    MobileMedia Ideas LLC v. Apple Inc., 
    780 F.3d 1159
    , 1172
    (Fed. Cir. 2015) (“Conclusory statements by an expert,
    however, are insufficient to sustain a jury’s verdict.”);
    Intellectual Sci. & Tech., Inc. v. Sony Elecs., Inc., 
    589 F.3d 1179
    , 1185–86 (Fed. Cir. 2009) (conclusory statement by
    expert, standing alone, insufficient to support jury finding
    of fact). Zoll’s expert explained how Wiley disclosed the
    other elements of claim 7, and Philips does not contend
    that Wiley fails to disclose any of those other features.
    Philips also argues that even if Wiley discloses all of
    the steps of claim 7, Wiley does not anticipate because it
    does not disclose performing each step in the order speci-
    fied in the claim. But we generally do not construe meth-
    od claims to require a specific ordering of the steps unless
    the claims explicitly recite or implicitly require such an
    ordering. See Interactive Gift Express, Inc. v. Compuserve
    Inc., 
    256 F.3d 1323
    , 1342–43 (Fed. Cir. 2001). Philips
    made no request at the district court for a narrowing
    KONINKLIJKE PHILIPS N.V. v.                                15
    ZOLL MEDICAL CORPORATION
    construction of claim 7 that would require the steps of the
    method to be performed in any particular order, and we
    see nothing in the language of that claim to warrant such
    a construction on appeal.
    Therefore, even drawing all inferences from the trial
    evidence in Philips’s favor, no reasonable jury could have
    found that Wiley fails to anticipate claim 7. As such, we
    reverse the district court’s denial of JMOL of invalidity as
    to claim 7 of the self-test ’460 patent.
    C. Claim 43 of the ’374 Self-Test Patent
    The jury found that claim 43 of the self-test ’374 pa-
    tent was not anticipated by the VIVAlink product bro-
    chure. Claim 43 recites the following:
    An external defibrillator comprising:
    a high-voltage delivery system; and
    a self-test system, the self-test system com-
    prising a test signal generator and a fail-safe vis-
    ual display.
    Zoll argues that no reasonable jury could conclude that
    VIVAlink fails to disclose each of these features. We
    agree.
    The VIVAlink brochure is a product brochure describ-
    ing the VIVAlink AED defibrillator device. Among other
    features, the VIVAlink brochure notes the “Ease of
    Maintenance” of the VIVAlink AED. J.A. 14942. Under
    that heading, the VIVAlink brochure explains:
    While the VivaLink AED is dormant, the micro-
    processor will automatically check the conditions
    of the battery, the electrodes/electrode cables and
    the internal electronics every 24 hours. On a
    weekly basis, it will automatically check the ca-
    pacitor, the charging circuit and the high voltage
    circuit. If any system is not within preset specifi-
    16                               KONINKLIJKE PHILIPS N.V. v.
    ZOLL MEDICAL CORPORATION
    cations, an audible and visual warning (Mainte-
    nance Alert) is triggered. Audible warnings will
    last until the batteries are exhausted but the vis-
    ual warning signal will remain indefinitely. The
    visual warning signal can be clearly seen simply
    by looking at the VivaLink AED.
    J.A. 14942. According to Zoll, this self-testing procedure
    discloses the “test signal generator” of claim 43, and the
    visual warning discloses the “fail-safe visual display.”
    Whether the visual warning of the VIVAlink brochure
    discloses the “fail-safe visual display” of claim 43 depends
    on the meaning of that claim feature. The district court
    did not provide any explicit construction for that claim
    term. J.A. 101–03. The specification of the ’374 patent
    suggests that the “fail-safe” feature requires the visual
    display to continue displaying some visual indicator even
    if the electrical power to the device is lost. See ’374 pa-
    tent, col. 5 ll. 34–39 (“The status indicator should be fail-
    safe so that the indicator will indicate an inoperable
    status if the system monitor should fail.”), col. 5 l. 66–
    col 6 l. 5 (“The primary advantages of the visual display of
    the preferred embodiment are its low power requirements
    and the fact that it is powered by an AC signal rather
    than a DC signal. This latter point assures the display’s
    fail-safe nature, since the shutter of the middle plate 66
    cannot be maintained opaque without the active involve-
    ment of the system monitor generating the AC signal.”).
    Philips urges a narrower construction of “fail-safe vis-
    ual display.” According to Philips, a display is fail-safe
    not just by maintaining a visual indicator when electrical
    power is lost, but by affirmatively displaying a negative
    indicator (like “NOT OK”) when the electrical power is
    lost. See Philips Reply Br. 42–46. According to Philips,
    the visual warning of the VIVAlink brochure may contin-
    ue displaying a positive indicator (like “OK”) when the
    electrical power is lost if that was the status indicator at
    KONINKLIJKE PHILIPS N.V. v.                                  17
    ZOLL MEDICAL CORPORATION
    the time of power loss. Therefore, according to Philips,
    the visual indicator of the VIVAlink brochure is not a
    “fail-safe visual display.”
    But neither the broad language of claim 43 nor the
    general description of the fail-safe visual display in the
    specification of the ’374 patent requires such a narrow
    meaning of “fail-safe.” It is certainly possible that a “fail-
    safe” display may actively change from a positive to a
    negative indicator if electrical power is lost, but this is not
    required by the claims. “Fail-safe” simply requires that a
    visual indicator persists even if the device loses electrical
    power. The VIVAlink brochure clearly discloses this.
    Philips’s alleged evidence supporting its narrower
    claim construction is unpersuasive. Philips cites primari-
    ly to its own expert’s testimony discussing the visual
    display of Zoll’s defibrillator device as part of the in-
    fringement case. See Philips Reply Br. 42–44. Evidence
    regarding the characteristics of the accused products is
    not pertinent to define the scope of the asserted claims.
    The only actual evidence that Philips presented to the
    jury regarding the visual warning of VIVAlink was the
    following statement by Philips’s expert witness about the
    VIVAlink brochure:
    Yes. This is very, very short, you know, a few
    pages brochure. And the relevant part for this
    consideration is right here. This is the only in-
    formation available. So this does not really dis-
    close the entire self-test because it does not teach
    how to make or use self-test. It does not disclose
    fail-safe visual display. More importantly, it does
    not disclose turning on of the power systems in re-
    sponse to a test signal, which is a critical part of a
    self-test.
    J.A. 5095–96 (underlining added). This conclusory state-
    ment does nothing more than state Philips’s preferred
    conclusion that the claim feature is not disclosed by the
    18                                KONINKLIJKE PHILIPS N.V. v.
    ZOLL MEDICAL CORPORATION
    prior art. It provides no evidence on which the reasonable
    jury could rely. See 
    MobileMedia, 780 F.3d at 1172
    . And
    Zoll did explain the visual warning of VIVAlink to the
    jury and why it is “fail-safe.” See J.A. 2864–65. There-
    fore, the evidence overwhelmingly shows that the
    VIVAlink visual warning that “will remain indefinitely”
    despite exhaustion of the batteries is a “fail-safe visual
    display.”
    Philips seeks to buttress its position by arguing that
    the VIVAlink brochure does not enable a fail-safe visual
    display. See Philips Reply Br. 46–47. But Philips’s expert
    said nothing whatsoever about enablement of the “fail-
    safe visual display” feature; his statement that VIVAlink
    “does not teach how to make or use” was directed strictly
    at the “self-test” feature, not the “fail-safe visual display.”
    See J.A. 5095–96. In any event, such a conclusory state-
    ment is insufficient to prove lack of enablement of a prior
    art reference. See 
    MobileMedia, 780 F.3d at 1172
    .
    Therefore, we conclude, based on the evidence pre-
    sented at trial, that no reasonable jury could have found
    that the VIVAlink brochure fails to anticipate claim 43.
    As such, we reverse the district court’s denial of JMOL of
    invalidity as to claim 43 of the self-test ’374 patent.
    D. Claims 42 and 67–68 of the ’374 Self-Test Patent
    The jury found that claims 42 and 67–68 of the ’374
    self-test patent were not obvious over the Zoll PD1400
    defibrillator. Claim 42 recites the following:
    A method for automatically determining and
    indicating an operational status of an external de-
    fibrillator, the method comprising the following
    steps:
    generating a test signal within the external
    defibrillator automatically and periodically;
    KONINKLIJKE PHILIPS N.V. v.                                19
    ZOLL MEDICAL CORPORATION
    performing a self-test in response to the test
    signal; and
    indicating the operational status of the defib-
    rillator based on a result of the self-test;
    the generating, performing, and indicating
    steps being performed prior to any attempted use
    of the defibrillator.
    Claim 67 is an independent claim that recites a simi-
    lar method as claim 42. Claim 68 is dependent on claim
    67. Obviousness is a question of law based on underlying
    questions of fact, see Perfect Web Techs., Inc. v. InfoUSA,
    Inc., 
    587 F.3d 1324
    , 1327 (Fed. Cir. 2009), and we review
    the ultimate conclusion of obviousness de novo and the
    underlying factual findings, implicitly in favor of the
    verdict, under the regional circuit’s reasonable jury
    standard, see Fresenius USA, Inc. v. Baxter Int’l, Inc., 
    582 F.3d 1288
    , 1294 (Fed. Cir. 2009). Zoll argues that the
    PD1400 defibrillator renders each of claims 42 and 67–68
    obvious. We disagree.
    Zoll alleges that the only feature of claims 42 and 67–
    68 differentiating them from the prior art is that the
    claims require the self-testing to be done “automatically,”
    i.e., not in response to a human pushing a button. See
    Zoll’s Principal Br. 36–39. Philips does not refute this
    characterization. See Philips’s Reply Br. 50–54. Instead,
    Philips argues that the automation of the self-tests was a
    non-obvious improvement. And Philips points to numer-
    ous indicia of non-obviousness supporting this conclusion.
    The evidence supporting the jury’s verdict of no inva-
    lidity is considerable. Philips’s expert witness explained
    that the Patent Office considered and rejected the position
    that user-initiated self-testing renders the claims obvious.
    J.A. 5097. Philips’s expert testified that designing an
    automatic self-test prior to user intervention presented
    challenges in managing battery power consumption that
    20                               KONINKLIJKE PHILIPS N.V. v.
    ZOLL MEDICAL CORPORATION
    were not obvious to overcome. J.A. 1827, 1839–40.
    Philips’s witnesses testified that the automatic self-test
    feature was critical in allowing the defibrillators to be
    stowed unsupervised in public spaces. J.A. 1817, 1828–
    29, 1407–10, 2026–27. Philips’s expert witness testified
    that the self-test feature, allowing for public and unsu-
    pervised stowage of the defibrillators, met a long-felt but
    unmet need. J.A. 5101–02. Philips demonstrated market
    success of its defibrillators incorporating the automatic
    self-test feature, that success stemming in part from the
    ability to sell the defibrillators over-the-counter and for
    home use. J.A. 1355, 2030–31.
    All of this evidence taken together provides ample ba-
    sis from which a reasonable jury could conclude that
    claims 42 and 67–68 would not have been obvious over
    user-instigated self-testing defibrillators. Zoll’s counter-
    argument and accompanying evidence put forward the
    position that automating user-instigated self-tests to run
    automatically would have been obvious. But this does not
    render the sum of the evidence supporting the opposite
    conclusion somehow lacking. We will therefore not dis-
    turb the ultimate legal conclusion that the claims would
    not have been obvious over the PD1400 defibrillator and
    other user-instigated self-testing devices.
    Therefore, we affirm the district court’s denial of
    JMOL of invalidity as to claims 42 and 67–68 of the self-
    test ’374 patent.
    IV. DIRECT INFRINGEMENT OF THE WAVEFORM
    AND SELF-TEST CLAIMS
    The jury found that Zoll directly infringes numerous
    claims of the waveform and self-test patents. Zoll con-
    tests the jury’s verdict on two general grounds: first, that
    Zoll’s devices do not perform the features of some of the
    claims; second, that even if Zoll’s devices perform the
    features of the claims, Zoll is not the party using the
    devices in a directly infringing way. Infringement is a
    KONINKLIJKE PHILIPS N.V. v.                                21
    ZOLL MEDICAL CORPORATION
    question of fact that we review under the regional circuit’s
    reasonable jury standard. See AstraZeneca LP v. Apotex,
    Inc., 
    633 F.3d 1042
    , 1056 (Fed. Cir. 2010); Marcano
    
    Rivera, 415 F.3d at 167
    .
    A. Waveform Claims – Claim Construction
    The jury found that Zoll directly infringes claim 51 of
    the ’454 waveform patent and claims 4 and 8 of the ’905
    waveform patent. Zoll argues that this verdict was in
    error because the district court presented an incorrect
    construction of those claims to the jury. We disagree.
    The waveform claims recite “A method for applying
    electrotherapy to a patient” in the preamble, a step of
    “discharging the energy source,” and a step of “monitoring
    [a patient-dependent / an] electrical parameter during the
    discharging step.” The district court construed the “dis-
    charging” and “monitoring” steps to mean, respectively,
    “the step of discharging the energy source” and “measur-
    ing one or more times.” J.A. 101.
    Zoll argues that this construction was in error. Zoll
    argues that recitation of “applying electrotherapy” in the
    preamble means that the “discharging” step includes
    discharging only a therapeutic level (i.e., a high voltage or
    current) of electrical shock, and does not include discharg-
    ing any non-therapeutic level (i.e., a low voltage or cur-
    rent) of electrical shock. According to Zoll, devices such as
    its own that first deliver a non-therapeutic level of electri-
    cal shock as a “test pulse” and then a therapeutic level of
    electrical shock do not infringe, at least if the “monitor-
    ing” step is performed only during the test pulse.
    But Zoll’s claim construction is not correct. The ordi-
    nary meaning of the claim language does not suggest the
    narrow construction of the “discharging” step that Zoll
    argues. The phrase “applying electrotherapy” in the
    preamble simply provides a setting for the method as a
    whole, not any sort of clear narrowing of the “discharging”
    22                               KONINKLIJKE PHILIPS N.V. v.
    ZOLL MEDICAL CORPORATION
    step as Zoll proffers. Zoll notes that the ’454 patent
    identifies a prior art reference, Kerber, that uses test
    pulses. See ’454 patent, col. 3 ll. 9–19. But there is noth-
    ing in this discussion to suggest that the ’454 patent
    disclaims any use of separate test pulses in its disclosed
    techniques, which, according to the patent, are distin-
    guished by automatic monitoring and shaping (or other
    fine-tuning) of the waveform of the electrical energy
    delivered to the patient during discharge itself. See, e.g.,
    ’454 patent, col. 3 ll. 45–54. This passage identifies that
    the use of test pulses was known, but it does not state
    that the use of test pulses was incompatible with the
    invention of the ’454 patent. See Ventana Med. Sys., Inc.
    v. Biogenex Labs., Inc., 
    473 F.3d 1173
    , 1181 (Fed. Cir.
    2006) (“[G]eneral statements by the inventors indicating
    that the invention is intended to improve upon prior art”
    techniques, without more, “will not be interpreted to
    disclaim every feature of every prior art device discussed
    in the ‘BACKGROUND ART’ section of the patent.”).
    Similarly, the discussion of the prior art Bell refer-
    ence in the prosecution history of the ’905 patent simply
    indicates that the Bell reference did not perform any
    “monitoring” step during an electrical discharge, because
    the waveform was determined based on a patient weight
    value input into the defibrillator prior to discharge. J.A.
    9186 (patentee arguing that “[s]ince it delivers a quantity
    of energy determined by a selection made by the operated
    prior to delivery of the shock, the Bell device does not
    adjust energy delivered to the patient based on a value of
    an electrical parameter monitored during discharge, as
    required by” the claims). That is, the patentee did not
    argue that Bell fails to anticipate because a separate test
    pulse prior to a therapeutic discharge is excluded by the
    claims, but instead argued that Bell fails to disclose
    monitoring during discharge, which is required by the
    claims. This makes no disclaimer of use of test pulses as
    part of the “discharging” step.
    KONINKLIJKE PHILIPS N.V. v.                              23
    ZOLL MEDICAL CORPORATION
    Neither the ordinary meaning of the claim language
    nor the intrinsic record show any merit in Zoll’s overly-
    narrow construction of the “discharging” step of the
    waveform method claims. Therefore, Zoll’s claim con-
    struction arguments provide no basis to overturn the
    district court’s denial of JMOL of no infringement as to
    claim 51 of the ’454 waveform patent and claims 4 and 8
    of the ’905 waveform patent.
    B. Waveform Method Claims
    Zoll alternatively argues that even if its defibrillator
    devices can be used to infringe the waveform method
    claims, Zoll does not use those devices in a directly in-
    fringing way. We disagree.
    Claim 51 of the ’454 patent and claims 4 and 8 of the
    ’905 patent require “discharging the energy . . . to the
    patient.” Therefore, only the party that performs the
    therapeutic method on a subject patient can directly
    infringe.
    Philips presented various elements of evidence
    demonstrating that Zoll used its defibrillator devices on
    subject patients. Zoll’s fact witness testified that Zoll
    conducted clinical trials on its defibrillator devices. J.A.
    1953. That same witness explained that Zoll performed
    these clinical trials to establish points of comparison
    between the Zoll defibrillators and competing products for
    the purpose of generating marketing material. J.A. 1969.
    Other of Zoll’s marketing materials stated that Zoll had
    performed “human clinical studies” involving testing on
    more than 2,800 patients. J.A. 14569. Zoll’s fact witness
    explained that Zoll’s clinical testing involved testing on
    actual human subjects and testing on products already on
    sale. J.A. 2484. Zoll’s expert witness further confirmed
    that clinical testing of the products by Zoll would involve
    testing on human subjects. J.A. 1687.
    24                                KONINKLIJKE PHILIPS N.V. v.
    ZOLL MEDICAL CORPORATION
    While Zoll notes that the first set of clinical trials ref-
    erenced by its witnesses were performed outside the
    statutory damages period, J.A. 1952–53, see 35 U.S.C.
    § 286 (“[N]o recovery shall be had for any infringement
    committed more than six years prior to the filing of the
    complaint or counterclaim for infringement in the ac-
    tion.”), Zoll demonstrates no such deficiency as to the
    other clinical trials that it admits to performing. And
    while Zoll claims that some of its clinical testing may
    have been protected under 35 U.S.C. § 271(e)(1) (“It shall
    not be an act of infringement to make, use, offer to sell, or
    sell within the United States or import into the United
    States a patented invention . . . solely for uses reasonably
    related to the development and submission of information
    under a Federal law which regulates the manufacture,
    use, or sale of drugs or veterinary biological products.”),
    Zoll’s witnesses admitted that the testing was performed
    to generate marketing materials and on products already
    on sale—thus not for the purpose of receiving approval
    from the Food and Drug Administration.
    Therefore, the jury’s verdict of direct infringement of
    the waveform method claims was supported by several
    independent elements of evidence showing that Zoll
    infringed the waveform method claims during its own
    product testing and trials. For this reason, and because
    we previously found no merit in Zoll’s claim construction
    arguments on the same claims, we affirm the district
    court’s denial of JMOL of no direct infringement as to
    claim 51 of the ’454 waveform patent and claims 4 and 8
    of the ’905 waveform patent.
    C. Waveform Device Claims
    The jury found that Zoll directly infringes claims 1
    and 5 of the ’212 waveform patent. Zoll argues that this
    verdict was in error, because Zoll does not use its defibril-
    lator devices in a directly infringing way. We disagree.
    Claim 1 recites the following:
    KONINKLIJKE PHILIPS N.V. v.                                 25
    ZOLL MEDICAL CORPORATION
    An external defibrillator comprising:
    an energy source;
    first and second electrodes in electrical com-
    munication with the exterior of a patient; [and]
    a controller . . . .
    Claim 5 is dependent on claim 1.
    Zoll first argues that Philips presented insufficient ev-
    idence establishing that Zoll uses its defibrillator products
    in an infringing way. However, the evidence presented by
    Philips and discussed for the waveform method claims is
    also sufficient for the jury to conclude that Zoll’s use of its
    defibrillator devices, i.e., the performance of testing and
    trials of its defibrillator products, directly infringed the
    waveform device claims.
    Zoll also argues that, because the claims require a de-
    fibrillator with electrodes “in electrical communication
    with the exterior of a patient,” Zoll does not directly
    infringe by making or selling its defibrillator products.
    Philips argues that Zoll infringes the waveform device
    claims through making and selling its defibrillator prod-
    ucts because the claim language of “in electrical commu-
    nication with the exterior of a patient” is functional
    language that does not limit the scope of the claims.
    Under this reasoning, the accused devices would not need
    to be in contact with a subject to infringe the claims, so
    Zoll would directly infringe the claims by simply making
    and selling its defibrillator devices.
    Philips cites various precedents of this court as to why
    we should read “in electrical communication with the
    exterior of a patient” out of the claims. Philips argues
    that this language is alternatively a statement of intend-
    ed use, the reading of a method step into device claims, or
    a nonsensical incorporation of a human being into the
    claim scope. But none of these arguments evade the fact
    26                                KONINKLIJKE PHILIPS N.V. v.
    ZOLL MEDICAL CORPORATION
    that “in electrical communication with the exterior of a
    patient” recites a clear, coherent limitation of the “first
    and second electrodes.” The electrodes must be attached
    to a subject patient in order for a defibrillator device to
    come within the scope of the waveform device claims.
    Philips would have us read the claims as if they recited
    “first and second electrodes” configured to be placed in
    “electrical communication with the exterior of a patient,”
    or something to that effect. But that is not what the
    claims recite. The claims must be interpreted according
    to their clear, ordinary meaning. See Ancora Techs., Inc.
    v. Apple, Inc., 
    744 F.3d 732
    , 734–35 (Fed. Cir. 2014).
    Under that meaning, the electrodes must be in electrical
    communication with a subject patient, and Zoll does not
    infringe those claims by making and selling its defibrilla-
    tor devices.
    Therefore, Philips presented sufficient evidence to
    support the jury’s verdict of direct infringement as to
    Zoll’s use of its defibrillator devices during product testing
    and trials, but not as to Zoll’s making and selling of its
    defibrillator devices. We affirm the district court’s denial
    of JMOL of no direct infringement on this basis as to
    claims 1 and 5 of the ’212 waveform patent.
    D. Self-Test Method Claims
    The jury found that Zoll directly infringes claim 7 of
    the ’460 self-test patent and claims 42 and 67–68 of the
    ’374 self-test patent. 3 Zoll argues that this verdict was in
    error, because Philips presented insufficient evidence that
    Zoll uses its own defibrillators in a directly infringing
    way, and that Zoll’s sale of its defibrillator devices do not
    3  Because we find that claim 7 of the ’460 self-test
    patent is invalid, we do not reach the direct infringement
    issue as to that claim.
    KONINKLIJKE PHILIPS N.V. v.                                   27
    ZOLL MEDICAL CORPORATION
    directly infringe these self-test method claims. We disa-
    gree.
    These claims recite a method for performing various
    self-test techniques in a defibrillator device. Claim 67 of
    the ’374 self-test patent, for instance, recites the follow-
    ing:
    A method for testing and indicating an opera-
    tional status of an external defibrillator compris-
    ing the following steps:
    generating a test signal within the external
    defibrillator automatically and periodically;
    performing a plurality of self-tests in response
    to the test signal to determine the operational sta-
    tus of a plurality of components of the defibrilla-
    tor, the tests being performed without human
    intervention prior to any attempted use of the de-
    fibrillator; and
    indicating the operational status of the defib-
    rillator in response to at least one of the self-tests.
    Zoll first argues that Philips presented insufficient ev-
    idence that Zoll uses its own defibrillator devices in a
    directly infringing way. But the record includes ample
    evidence on which the jury could rely in order to conclude
    that Zoll’s product testing and trials involved use of the
    defibrillator devices in a way that directly infringes the
    self-test method claims. A Zoll employee admitted that
    Zoll performs testing of its products, including the self-
    test functionality, prior to sale to verify that they function
    properly. J.A. 1897–98, 2481–84. Philips presented test
    reports by Zoll regarding its testing of the self-test fea-
    ture. J.A. 13615–19, 13774–76. Philips’s expert witness
    explained to the jury the significance of both of these
    pieces of evidence. J.A. 1897–99. This was a sufficient
    evidentiary basis on which a reasonable jury could con-
    28                                KONINKLIJKE PHILIPS N.V. v.
    ZOLL MEDICAL CORPORATION
    clude that Zoll directly infringed the self-test method
    claims by its pre-sale product testing.
    Zoll next argues that it does not directly infringe the
    self-test method claims by making or selling its defibrilla-
    tor devices, because it is some other party, e.g., Zoll’s
    customers, that actually perform the steps of the claims.
    Zoll’s point is that the steps of the self-test method claims,
    such as “generating a test signal within the external
    defibrillator automatically and periodically,” are steps
    that are performed on an ongoing basis after Zoll has
    already sold the defibrillator device to another party. So,
    Zoll must not be the party performing the directly infring-
    ing use of the self-test method claims.
    It is true that a party that sells an apparatus capable
    of performing a patented method is generally not liable
    for direct infringement if that infringing act comes to
    pass. See Moba, B.V. v. Diamond Automation, Inc., 
    325 F.3d 1306
    , 1313 (Fed. Cir. 2003). Instead, the direct
    infringer would be the party who put that apparatus to
    use to perform the patented method. See Ericsson, Inc. v.
    D-Link Sys., Inc., 
    773 F.3d 1201
    , 1221 (Fed. Cir. 2014).
    But this case presents the complicating detail that Zoll
    may sell the defibrillators configured to automatically
    perform the self-test method claims without any addition-
    al intervention by Zoll’s customers. Compare J.A. 1899,
    with J.A. 5266, 7055, 12143–49. Philips argues that such
    “automatic” infringement establishes direct infringement
    by the seller of the apparatus, relying on SiRF Technolo-
    gy, Inc. v. International Trade Commission, 
    601 F.3d 1319
    (Fed. Cir. 2010). But Philips’s argument seeks to extend
    the holding in SiRF to a place where we have previously
    declined to take it:
    Contrary to Ericsson’s assertions, our decision in
    SiRF did not create direct infringement liability
    whenever an alleged infringer sells a product that
    is capable of executing the infringing method.
    KONINKLIJKE PHILIPS N.V. v.                              29
    ZOLL MEDICAL CORPORATION
    Our decision in SiRF is not applicable here be-
    cause all of the steps of the method in claims 1
    and 2 of the ’215 patent are performed on the end
    product, which is controlled by a third party. See
    
    SiRF, 601 F.3d at 1331
    . Unlike the method in
    SiRF, there are no steps automatically performed
    by equipment controlled by [the selling party]. In
    fact, none of our decisions have found direct in-
    fringement of a method claim by sales of an end
    user product which performs the entire method,
    and we decline to do so here.
    Ericsson, 
    773 F.3d 1221
    –22. We again decline to extend
    the scope of direct infringement to the point that Philips
    advocates. As in Ericsson, all of the steps of the self-test
    method claims are performed by the defibrillator devices,
    wholly out of the control of Zoll. Furthermore, there is
    considerable conflict in the record as to whether Zoll’s
    defibrillator will actually automatically perform the self-
    test method claims upon sale to a Zoll customer, or
    whether some further activation and installation steps
    are required by the purchaser before the defibrillator will
    perform those methods. As such, we do not find this to be
    an appropriate case in which to establish direct infringe-
    ment liability for a seller of an apparatus that may per-
    form patented methods.
    Therefore, Philips presented sufficient evidence to
    support the jury’s verdict of direct infringement as to
    Zoll’s own use of its defibrillator devices during product
    testing and trials, but not as to Zoll’s alleged use of the
    self-test method claims by sale of its defibrillator prod-
    ucts. We affirm the district court’s denial of JMOL of no
    direct infringement on this basis as to claims 42 and 67–
    68 of the ’374 self-test patent.
    30                               KONINKLIJKE PHILIPS N.V. v.
    ZOLL MEDICAL CORPORATION
    V. INDIRECT INFRINGEMENT OF THE WAVEFORM
    AND SELF-TEST CLAIMS
    The jury found that Zoll does not contributorily in-
    fringe claim 51 of the ’454 waveform patent, claims 4 and
    8 of the ’905 waveform patent, claim 7 of the ’460 self-test
    patent, and claims 42–43 and 67–68 of the ’374 self-test
    patent. 4 A party is liable for contributory infringement
    under 35 U.S.C. § 271(c) if: 1) “there is direct infringe-
    ment,” 2) “the accused infringer had knowledge of the
    patent,” 3) “the component has no substantial noninfring-
    ing uses,” and 4) “the component is a material part of the
    invention.” Fujitsu Ltd. v. Netgear Inc., 
    620 F.3d 1321
    ,
    1326 (Fed. Cir. 2010). Philips argues that, based on the
    evidence presented at trial, no reasonable jury could have
    concluded that any of these four requirements were not
    met by Zoll for the waveform and self-test patents. We
    address each of the four requirements in turn.
    A. Direct Infringement
    Philips alleges that customers of Zoll performed the
    requisite acts of direct infringement for the contributory
    infringement claim against Zoll. Zoll responds that
    Philips failed to prove that any of Zoll’s customers actual-
    ly performed this direct infringement.
    In preceding portions of this opinion, we have already
    explained that sufficient evidence demonstrated that Zoll
    infringed each of the contested waveform and self-test
    method claims when performing testing and trials on its
    own defibrillator devices in the manner in which they
    were intended to operate. A Zoll employee testified that
    Zoll controls about 50% of the North American hospital
    4  Because we find that claim 7 of the ’460 self-test
    patent and claim 43 of the ’374 self-test patent are inva-
    lid, we do not reach the contributory infringement issue
    as to those claims.
    KONINKLIJKE PHILIPS N.V. v.                              31
    ZOLL MEDICAL CORPORATION
    market and about 40% of the ambulance market. J.A.
    1953. Therefore, for the jury to conclude that the direct
    infringement requirement of the contributory infringe-
    ment claim was not met, it would have had to conclude
    that not a single one of Zoll’s customers in this sizable
    share of the market used the devices for their intended
    purposes as Zoll itself does. Absent any evidence suggest-
    ing such a strange occurrence, this is not a conclusion
    that could be reached by a reasonable jury.
    Therefore, lack of direct infringement cannot stand as
    the basis for the jury’s verdict of no contributory in-
    fringement.
    B. Knowledge
    Philips alleges that Zoll had the requisite knowledge
    of the waveform and self-test patents as of 2008 based on
    an infringement contention letter that Philips delivered to
    Zoll. Zoll alleges that these infringement contentions
    were not sufficiently specific to establish the requisite
    knowledge, and that Zoll had a good faith belief in non-
    infringement.
    Section 271(c) “require[s] a showing that the alleged
    contributory infringer knew that the combination for
    which his component was especially designed was both
    patented and infringing.” Aro Mfg. Co. v. Convertible Top
    Replacement Co., 
    377 U.S. 476
    , 488 (1964); see also Gold-
    en Blount, Inc. v. Robert H. Peterson Co., 
    365 F.3d 1054
    ,
    1061 (Fed. Cir. 2004). Zoll undoubtedly knew about the
    waveform and self-test patents and Philips’s allegation of
    infringement as of the date of Philips’s infringement
    letter, dated 28 July 2009. J.A. 12706–13. The July 2009
    letter specifically identifies the ’460 self-test patent and
    ’374 self-test patent and refutes some previously dis-
    cussed theory of invalidity. J.A. 12710. The July 2009
    letter further discusses two family member patents of the
    ’454, ’905, and ’212 waveform patents, those family mem-
    ber patents having considerably similar claims as the
    32                               KONINKLIJKE PHILIPS N.V. v.
    ZOLL MEDICAL CORPORATION
    asserted waveform patents. J.A. 12706. The July 2009
    letter also addressed the same non-infringement conten-
    tion as to the waveform patents that Zoll ultimately
    raised at trial. J.A. 12706.
    Zoll argues that its good faith belief in non-
    infringement negates the knowledge requirement, point-
    ing to its arguments against the direct infringement
    verdicts discussed supra at 20–29. For the claims of the
    ’454 waveform patent and the ’905 waveform patent, we
    find that Zoll’s belief in non-infringement, based on its
    reasonable claim construction argument, does negate the
    knowledge requirement of contributory infringement.
    The Supreme Court has explained that if an accused
    infringer “reads the patent’s claims differently from the
    plaintiff,” and if “that reading is reasonable,” then the
    accused infringer should not be liable for indirect in-
    fringement. Commil USA, LLC v. Cisco Sys., Inc., 
    135 S. Ct. 1920
    , 1928 (2015). While we ultimately concluded
    that Zoll’s claim construction argument against the jury’s
    direct infringement verdict for the waveform claims was
    incorrect, see supra at 21–23, that argument was based on
    a reasonable interpretation of the claims in light of the
    specification and the prosecution history. Because this
    belief in non-infringement was reasonable, it is a suffi-
    cient basis on which to ground the jury’s implicit finding
    of insufficient knowledge for contributory infringement.
    But for the claims of the ’374 self-test patent, Zoll’s
    non-infringement contentions amounted to nothing more
    than an allegation that Zoll’s customers, not Zoll, were
    using the Zoll defibrillator devices in a directly infringing
    way. See supra at 26–29. This is not a defense to the
    knowledge requirement for contributory infringement
    because it evinces that Zoll knew it was potentially con-
    tributing to direct infringement of the ’374 self-test pa-
    tent. Therefore, Zoll had the requisite knowledge of the
    ’374 self-test patent and infringement as of July 28, 2009.
    KONINKLIJKE PHILIPS N.V. v.                              33
    ZOLL MEDICAL CORPORATION
    Philips suggests that Zoll had this knowledge even
    earlier. A Zoll employee admitted to being notified of
    Philips’s allegations of infringement as early as 2008.
    J.A. 1958–59, 1978–80. The July 2009 letter also is
    clearly a continuation of some ongoing discussion between
    counsel for Philips and Zoll. However, Philips does not
    direct our attention to any proof of this earlier 2008
    infringement contention, and we cannot assume that it
    was presented to the jury given that it does not appear in
    the record before us. Therefore, we are limited to saying
    that no reasonable jury could have concluded that Zoll
    lacked knowledge of the ’374 self-test patent and Philips’s
    allegations of infringement as of July 2009.
    Accordingly, as of July 2009, lack of knowledge of the
    patents and infringement cannot stand as the basis for
    the jury’s verdict of no contributory infringement for the
    claims of the ’374 self-test patent. However, lack of
    knowledge of the patents and infringement can stand as
    the basis for the jury’s verdict of no contributory in-
    fringement for the claims of the ’454 waveform patent and
    the ’905 waveform patent.
    C. Substantial Non-Infringing Use
    Philips alleges that the Zoll defibrillators do not have
    any substantial non-infringing use for the self-test fea-
    tures. In response, Zoll identifies several allegedly non-
    infringing uses that it claims the jury could have relied on
    to reach its verdict.
    An accused contributory infringer will not be held lia-
    ble for such infringement if the “component” or “material
    or apparatus” that that party sells is “suitable for sub-
    stantial noninfringing use.” § 271(c); see also Ricoh Co.,
    Ltd. v. Quanta Comput. Inc., 
    550 F.3d 1325
    , 1337 (Fed.
    Cir. 2008). A complication arises when the asserted
    patent claims cover only one aspect or feature of the
    “component” or “material or apparatus” that the accused
    contributory infringer sells. See 
    Ricoh, 550 F.3d at 1337
    –
    34                              KONINKLIJKE PHILIPS N.V. v.
    ZOLL MEDICAL CORPORATION
    40. That complication is present in this case, because the
    self-test features that are covered by the ’374 self-test
    patent are general features of the composite defibrillator
    devices.
    In such cases, we have sought to assure that the ac-
    cused contributory infringer is not “‘permitted to escape
    liability as a contributory infringer merely by embedding
    [the infringing apparatus] in a larger product with some
    additional, separable feature before importing and selling
    it.’” Lucent Techs., Inc. v. Gateway, Inc., 
    580 F.3d 1301
    ,
    1320 (Fed. Cir. 2009) (quoting 
    Ricoh, 550 F.3d at 1337
    (modifications in Lucent)). To reach this end, we have
    sought to determine whether the infringing component is
    “‘separate and distinct’” from other functions of the com-
    posite product. 
    Fujitsu, 620 F.3d at 1330
    (quoting i4i Ltd.
    P’ship v. Microsoft Corp., 
    598 F.3d 831
    , 849 (Fed. Cir.
    2010), aff’d on other grounds, 
    564 U.S. 91
    (2011)). In the
    cases where we have directly addressed this issue, we
    have generally been fairly liberal in finding the accused
    components separate. See 
    Fujitsu, 620 F.3d at 1330
    –31
    (finding message fragmentation feature of wireless access
    point devices separate and distinct from other features of
    those devices); 
    i4i, 598 F.3d at 848
    –49 (finding XML
    editor separate and distinct from other features of Mi-
    crosoft Word); 
    Lucent, 580 F.3d at 1321
    (finding date-
    picker tool separate and distinct from other features of
    Microsoft Outlook); 
    Ricoh, 550 F.3d at 1336
    –40 (vacating
    district court finding that optical disk drive has substan-
    tial non-infringing uses apart from patented disk-writing
    technology).
    For the self-test patents, Zoll argues that the jury
    could have found a substantial non-infringing use in the
    form of either automatic self-tests running on a single
    periodic schedule or self-tests running only when instigat-
    ed by a user. Zoll’s Principal Br. 63–64.
    KONINKLIJKE PHILIPS N.V. v.                               35
    ZOLL MEDICAL CORPORATION
    As to the user-instigated self-tests, a reasonable jury
    could only conclude that this is a “separate and distinct”
    feature from the automatic, periodic self-test feature. In
    Fujitsu, we considered a similar argument regarding the
    message fragmentation feature in IEEE 802.11 wireless
    access point devices. See 
    Fujitsu, 620 F.3d at 1330
    .
    There the accused contributory infringer argued that
    disabling packet fragmentation was a substantial non-
    infringing use. See 
    id. We held
    that disabling the pa-
    tented feature altogether was a separate and distinct
    mode of operation. See 
    id. In the
    present case, [the accused contributory in-
    fringer] argues that because a user can turn off
    the infringing features, then there are substantial
    noninfringing uses. However, it is undisputed
    that, when activated, the product is infringing.
    Whether a user activates fragmentation is rele-
    vant to the extent of direct infringement, but does
    not establish substantial noninfringing uses.
    
    Id. at 1331.
    This logic applies even more so here, where
    the record clearly shows that creation of the patented
    automatic, periodic self-tests was a key aspect of the
    products and allowed their proliferation in the market-
    place. Therefore, no reasonable jury could find disabling
    of this critical self-test feature to be anything but a sepa-
    rate and distinct mode of operation for the defibrillator
    devices.
    Zoll’s arguments regarding the use of a single periodic
    schedule for self-tests in its devices is inapposite, because
    only claim 7 of the ’460 self-test patent requires more
    than one schedule for periodic self-tests, and we have
    already found that claim invalid.
    Therefore, a substantial non-infringing use cannot
    stand as the basis for the jury’s verdict of no contributory
    infringement for the claims of the ’374 self-test patent.
    36                                 KONINKLIJKE PHILIPS N.V. v.
    ZOLL MEDICAL CORPORATION
    D. Material Part of the Invention
    Philips argues that the self-test features are material
    parts of the defibrillator devices, and Zoll does not contest
    the point. We also think the point is incontestable, and
    thus lack of materiality cannot stand as the basis for the
    jury’s contributory infringement verdict.
    *   *   *
    Based on the foregoing, we find that no reasonable ju-
    ry could have reached the actual jury’s verdict of no
    contributory infringement by Zoll, but only as to the
    claims of the ’374 self-test patent. Therefore, we reverse
    the district court’s denial of JMOL of contributory in-
    fringement as to claims 42 and 67–68 of the ’374 self-test
    patent, and we affirm the district court’s denial of JMOL
    of contributory infringement as to claim 51 of the ’454
    waveform patent and claims 4 and 8 of the ’905 waveform
    patent.
    VI. INDEFINITENESS OF ELECTRODE CLAIMS
    The jury found that claims 1, 8–9, 11–12, 19, and 24–
    25 of the ’526 patent were not invalid. Philips argues that
    this verdict was in error, either because no reasonable
    jury could find the claims are not indefinite, or because
    the district court improperly instructed the jury on the
    standard for indefiniteness. We agree with Philips’s
    latter argument.
    Claim 1 of the ’526 patent recites, in part:
    An electrode for transcutaneously delivering
    defibrillation pulses to a patient’s heart, the elec-
    trode comprising:
    a conducting plate . . . , and
    a layer of electrolytic gel comprising a concen-
    tration of an electrolyte that produces a combina-
    tion series resistance of two of said electrodes,
    KONINKLIJKE PHILIPS N.V. v.                                 37
    ZOLL MEDICAL CORPORATION
    when measured with the electrodes configured in
    a series circuit with a 50 Ω resistance, and with
    the electrolytic gel layer of each electrode in con-
    tact with that of the other electrode, that is great-
    er than 1 Ω when a 200 Joule defibrillation pulse
    is discharged into the series circuit . . . .
    Independent claim 24 recites a similar feature, and all of
    the other asserted claims are dependent on one of these
    two independent claims.
    The above-quoted language of claim 1 attempts to
    cover the inventive discovery of the ’526 patent, i.e., that
    low resistance of the electrode’s electrolytic gel is benefi-
    cial to a point, but not below 1 ohm of resistance. In order
    to specify this scope of claim coverage, claim 1 essentially
    instructs the reader to take a defibrillator device, place
    the two electrodes together with the electrolytic gel be-
    tween them—thus omitting the human subject from the
    circuit—arrange 50 ohms resistance in series with the
    electrodes, and then apply 200 joules of electrical energy
    into this circuit. With this configuration, the electrical
    resistance across the series of two electrodes and electro-
    lytic gel should be more than 1 ohm.
    “The Supreme Court has instructed that ‘a patent is
    invalid for indefiniteness if its claims, read in light of the
    specification delineating the patent, and the prosecution
    history, fail to inform, with reasonable certainty, those
    skilled in the art about the scope of the invention.’”
    SimpleAir, Inc. v. Sony Ericsson Mobile Commc’ns AB,
    
    820 F.3d 419
    , 432 (Fed. Cir. 2016) (quoting Nautilus, Inc.
    v. Biosig Instruments, Inc., 
    134 S. Ct. 2120
    , 2124 (2014)).
    The Supreme Court laid out this standard, the need to
    inform with reasonable certainty, in Nautilus, which
    effected a change in the law over our previous standard
    for determining indefiniteness: “amenable to construc-
    tion” or “insolubly ambiguous.” See Dow Chem. Co. v.
    Nova Chems. Corp., 
    803 F.3d 620
    , 630–31 (Fed. Cir.
    38                               KONINKLIJKE PHILIPS N.V. v.
    ZOLL MEDICAL CORPORATION
    2015). “Indefiniteness is a question of law that we review
    de novo, subject to a determination of underlying facts,”
    Akzo Nobel Coatings, Inc. v. Dow Chem. Co., 
    811 F.3d 1334
    , 1343 (Fed. Cir. 2016) (internal citations omitted),
    which we review under the regional circuit’s reasonable
    jury standard, Marcano 
    Rivera, 415 F.3d at 167
    .
    Philips argues that the claim scope is insufficiently
    definite to satisfy 35 U.S.C. § 112 ¶ 2. In particular,
    because neither the claims nor the specification clarify
    what temperature the procedure should be performed at,
    how old the electrodes should be, or how many previous
    electrical shocks should have been applied with the elec-
    trodes, the asserted claims of the ’526 patent fail to speci-
    fy the scope of the claims to a sufficiently reasonable
    degree of clarity. Philips provided expert testimony
    showing a significant degree of variance in measured
    resistance as each of these factors changed.
    But we do not find this evidence to be so clearly in fa-
    vor of finding the claims indefinite that we think it ap-
    propriate to overturn the jury’s verdict. The jury could
    have discounted Philips’s experimental results and expert
    testimony regarding room temperature because the
    experiments were performed at an energy level (150
    joules) different from the level specified by the claims (200
    joules). The jury could have viewed the evidence on
    number of sequential shocks and age of the electrodes as a
    relatively minor source of imprecision in the claims. It is
    uncontested that the resistance of the electrodes only
    increases as the number of sequential shocks and age of
    the electrodes increases. Therefore, the lack of precision
    for having not specified these parameters would only
    create a lack of clarity for an ordinary artisan if the
    electrodes showed a resistance less than, but close to, the
    1 ohm cutoff. Even then, the jury could have credited the
    opinion of Zoll’s expert witness, who testified that an
    ordinary artisan would understand the age of the elec-
    trode to be bounded by its date of expiration and the
    KONINKLIJKE PHILIPS N.V. v.                                39
    ZOLL MEDICAL CORPORATION
    number of sequential shocks to most likely be the first
    such shock.
    Therefore, while the lack of precise bounds on these
    three parameters may mean that the claims do not specify
    their scope with absolute precision, we cannot say that
    the evidence overwhelmingly proves by clear and convinc-
    ing evidence that the claims fail to specify their bounds
    with reasonable certainty. For this reason, we do not
    reverse the district court’s denial of JMOL of indefinite-
    ness.
    On the other hand, this elucidation of ambiguity in
    the scope of the claims does raise concern as to the charge
    the jury received prior to reaching its verdict. In instruct-
    ing the jury on the indefiniteness count, the district court
    stated the following:
    In this case, Philips contends that the claims of
    Zoll’s ’526 patent are invalid because the language
    of the claims is indefinite. To prevail on that con-
    tention, Philips must show by clear and convinc-
    ing evidence that a person of ordinary skill in the
    art would not understand what is and is not cov-
    ered by the claims of Zoll’s patent.
    The amount of detail required for a claim to be
    definite depends on the particular invention, the
    prior art, and the written description contained in
    the patent. Absolute clarity is not necessary. Ra-
    ther, only claims that are insolubly ambiguous are
    indefinite. The claim language need only be as
    precise as the subject matter permits. Further-
    more, the fact that a person of ordinary skill in
    the art would have to engage in some experimen-
    tation to determine the scope of the claim does not
    render the claim indefinite so long as the experi-
    mentation is not undue or excessive.
    40                               KONINKLIJKE PHILIPS N.V. v.
    ZOLL MEDICAL CORPORATION
    J.A. 5336. The district court presented these instructions
    to the jury prior to the Supreme Court’s decision in Nauti-
    lus, which explains why the language of “insolubly am-
    biguous” was included in those instructions. Philips
    argues that this instruction—“only claims that are insol-
    ubly ambiguous are indefinite”—was rendered legally
    incorrect by Nautilus and resulted in a prejudice to
    Philips.
    This court “will set aside the jury verdict, ‘if the mo-
    vant can establish that those instructions were legally
    erroneous, and that the errors had prejudicial effect.’”
    Commil USA, LLC v. Cisco Sys., Inc., 
    720 F.3d 1361
    ,
    1365–66 (Fed. Cir. 2013), rev’d on other grounds, 
    135 S. Ct. 1920
    (2015) (quoting Sulzer Textil A.G. v. Picanol
    N.V., 
    358 F.3d 1356
    , 1363 (Fed. Cir. 2004)) (internal
    quotation marks omitted).
    It is without dispute that the “insolubly ambiguous”
    standard is legally erroneous after Nautilus. See 
    Dow, 803 F.3d at 630
    –31. The only significant question in this
    case is whether the inclusion of the reference to the
    “insolubly ambiguous” standard in the broader instruc-
    tions on indefiniteness thereby effected a prejudice on
    Philips. We conclude that it did. While we have not
    clarified the relationship between “insolubly ambiguous”
    and “reasonably certain,” it must be admitted that the
    “insolubly ambiguous” standard is a harder threshold to
    meet than the post-Nautilus standard. Thus, if the jury
    actually applied the “insolubly ambiguous” standard, then
    it would be fair to conclude that the jury instructions
    prejudiced Philips, especially in light of the extensive case
    on indefiniteness that Philips presented—even though not
    sufficient to merit JMOL.
    Zoll argues that, taken in the broader context of the
    jury instructions (as quoted above), the reference to the
    “insolubly ambiguous” standard was innocuous and not
    prejudicial. While there may be some factual scenario
    KONINKLIJKE PHILIPS N.V. v.                               41
    ZOLL MEDICAL CORPORATION
    where the reference to “insolubly ambiguous” is non-
    prejudicial, this is not that case. Here, the sentence,
    “Rather, only claims that are insolubly ambiguous are
    indefinite,” is the strongest, most forceful statement in
    the entire instructions on indefiniteness. It seems almost
    certain that amidst the back-and-forth, give-and-take of
    the remainder of the jury instructions on indefiniteness,
    the jury would gravitate to the single, definitive state-
    ment in the instructions. Furthermore, this sentence is
    juxtaposed with, “Absolute clarity is not necessary,” and
    connected with “rather, only,” which slants the playing
    field against a finding of indefiniteness in a way that is no
    longer appropriate after Nautilus. On this basis, we find
    that the district court’s reference to the insolubly ambigu-
    ous standard was prejudicial.
    Therefore, while we do not find Philips’s case on indef-
    initeness to be so overwhelming as to mandate a reversal
    of JMOL, we believe that the jury instructions incorporat-
    ing the pre-Nautilus standard for indefiniteness warrant
    setting aside the jury verdict of no invalidity for indefi-
    niteness. We affirm the district court’s denial of JMOL of
    invalidity for indefiniteness, we reverse the district
    court’s denial of a new trial on invalidity for indefinite-
    ness, we vacate the jury verdict of no invalidity, and we
    remand the case for a new trial on invalidity for claims 1,
    8–9, 11–12, 19, and 24–25 of the ’526 patent. 5
    5   At trial, the only question of invalidity presented
    to the jury was indefiniteness. As discussed in the next
    section, an alleged prior art device, the Marquette elec-
    trode, might support additional theories of invalidity of
    the claims of the ’526 patent. If so, those questions should
    also be presented to the jury at a new trial on invalidity.
    42                                KONINKLIJKE PHILIPS N.V. v.
    ZOLL MEDICAL CORPORATION
    VII. ADMISSIBILITY OF EVIDENCE
    The district court excluded evidence related to two
    distinct elements of prior art that Philips desired to
    present to the jury as grounds for prior art-based invalidi-
    ty of the ’526 patent claims. Philips argues that each of
    these exclusions was in error and warrants the relief of a
    new trial on invalidity. 6 This court reviews evidentiary
    rulings under the law of the regional circuit, see AbbVie
    Deutschland GmbH & Co., KG v. Janssen Biotech, Inc.,
    
    759 F.3d 1285
    , 1295 (Fed. Cir. 2014), which the First
    Circuit reviews for abuse of discretion, see Acosa-Mestre v.
    Hilton Int’l of Puerto Rico, Inc., 
    156 F.3d 49
    , 56–57 (1st
    Cir. 1998).
    Philips attempted to present evidence related to a pri-
    or art device, the Marquette Responder 1200 electrode.
    To show that the Marquette electrode was an invalidating
    prior art reference on sale prior to the ’526 patent’s priori-
    ty date, Philips garnered three pieces of evidence: deposi-
    tion testimony of an employee of Marquette Electronics,
    J.A. 5680–89; a Marquette Electronics sales report, J.A.
    5676–79; and a Food and Drug Administration pre-
    marketing filing, a “510(k)” application, J.A. 5629–75. In
    denying the Marquette electrode as a ground of prior art
    invalidity, the district court stated:
    After consideration of the parties’ supplemental
    memoranda with respect to the 510K notifications
    to the Food and Drug Administration, Dockets No.
    522 and 523, the Court agrees with Zoll that such
    6   Because we have already granted Philips the re-
    quested relief of a new trial on invalidity for the ground of
    indefiniteness in the preceding section, this section ad-
    dresses only what grounds the district court may consider
    appropriate to be presented to the jury in that new inva-
    lidity trial.
    KONINKLIJKE PHILIPS N.V. v.                              43
    ZOLL MEDICAL CORPORATION
    notifications are not prior art under the Patent
    Act, and Zoll’s motion to exclude is therefore al-
    lowed.
    J.A. 5005. The district court then excluded the Marquette
    electrode 510(k) application “as well as any testimony
    that intends to rely upon” that 510(k) application.
    This court has repeatedly clarified that oral testimony
    can be used as the primary basis for evidencing prior art-
    based invalidity. See, e.g., TransWeb, LLC v. 3M Innova-
    tive Props. Co., 
    812 F.3d 1295
    , 1301–02 (Fed. Cir. 2016);
    Lazare Kaplan Int’l, Inc. v. Photoscribe Techs., Inc., 
    628 F.3d 1359
    , 1374 (Fed. Cir. 2010). The question to be
    answered when such an invalidity defense is proffered is
    whether the oral testimony is sufficiently corroborated by
    other evidence. See 
    TransWeb, 812 F.3d at 1301
    –02. This
    question is analyzed under a rule of reason approach and
    is a question of fact. See Fleming v. Escort Inc., 
    774 F.3d 1371
    , 1377 (Fed. Cir. 2014).
    Here, Philips attempted to use the Marquette elec-
    trode as a prior art device, not the 510(k) application as a
    prior art publication. See J.A. 5009–10. Philips intended
    to use the testimony of the Marquette employee to estab-
    lish the Marquette electrode as an invalidating prior art
    device on public sale prior to the priority date of the ’526
    patent. The sales report and 510(k) application were
    presented as evidence to corroborate this oral testimony of
    the Marquette employee. Therefore, the relevant legal
    question was whether the Marquette employee’s testimo-
    ny was sufficiently corroborated, not whether the 510(k)
    application was publicly available. By excluding the
    Marquette electrode evidence without answering the
    relevant legal question, the district court abused its
    discretion. See Highmark Inc. v. Allcare Health Mgmt.
    Sys., Inc., 
    134 S. Ct. 1744
    , 1748 n.2 (2014) (“‘A district
    court would necessarily abuse its discretion if it based its
    ruling on an erroneous view of the law or on a clearly
    44                                KONINKLIJKE PHILIPS N.V. v.
    ZOLL MEDICAL CORPORATION
    erroneous assessment of the evidence.’” (quoting Cooter &
    Gell v. Hartmarx Corp., 
    496 U.S. 384
    , 405 (1990))). How-
    ever, while this necessitates that we vacate the district
    court’s denial of Philips’s motion for a new trial, we do not
    think that it is so clear that a new trial on validity using
    the Marquette electrode is appropriate. It may be that
    the evidence provided to corroborate the Marquette em-
    ployee’s oral testimony is insufficient under our case law.
    Because this is a question of fact, we must remand the
    issue for determination by the district court in the first
    instance. And the question of corroboration is generally a
    question left to the jury, unless the district court con-
    cludes that there is insufficient corroboration as a matter
    of law. See Adenta GmbH v. OrthoArm, Inc., 
    501 F.3d 1364
    , 1372 (Fed. Cir. 2007).
    Philips also attempted to present a prior art invalidity
    defense based on a 510(k) application for the Physio-
    Control Fast-Patch. The district court excluded this
    evidence in the same passage quoted above. For this prior
    art defense, though, Philips attempted to use the 510(k)
    application as a prior art publication in its own right.
    “When considering whether a given reference qualifies as
    a prior art ‘printed publication,’ the key inquiry is wheth-
    er the reference was made ‘sufficiently accessible to the
    public interested in the art’ before the critical date.” Voter
    Verified, Inc. v. Premier Election Sols., Inc., 
    698 F.3d 1374
    , 1380 (Fed. Cir. 2012) (quoting In re Cronyn, 
    890 F.2d 1158
    , 1160 (Fed. Cir. 1989)).
    Philips theorizes that some member of the public
    could have found out about the application, requested it
    from the FDA, and then received it, because the confiden-
    tiality of the application had expired prior to the priority
    date of the ’526 patent. But this relies on a considerable
    amount of conjecture that is not supported by the record.
    As to this particular 510(k) application, Philips presented
    no evidence of indexing or cataloguing, which, while not
    prerequisites, serve as hallmarks of public accessibility.
    KONINKLIJKE PHILIPS N.V. v.                                45
    ZOLL MEDICAL CORPORATION
    See Voter 
    Verified, 698 F.3d at 1380
    . While the record
    shows that a third-party did request the 510(k) applica-
    tion using a Freedom of Information Act request prior to
    the priority date of the ’526 patent, J.A. 5586, the record
    also shows that the FOIA requester did not receive the
    510(k) application until after the ’526 patent’s priority
    date, J.A. 5585. The fact that the application was not
    received by a member of the public until then further
    supports the district court’s implicit determination that
    the Physio-Control 510(k) application was not sufficiently
    available to the public prior to the priority date of the ’526
    patent. Therefore, the district court did not abuse its
    discretion in excluding this evidence from the invalidity
    trial.
    Based on the foregoing, we affirm the district court’s
    denial of a new trial based on exclusion of the Physio-
    Control 510(k) application evidence, we vacate the district
    court’s denial of a new trial based on exclusion of the
    Marquette electrode device evidence, and we remand to
    the district court for a determination of whether the
    testimony as to the Marquette electrode is sufficiently
    corroborated to proceed in a new invalidity trial.
    VIII. CONCLUSION
    For the reasons stated herein, we act on the district
    court’s judgments as follows:
    we affirm the district court’s denial of JMOL of inva-
    lidity as to claims 4 and 8 of the waveform ’905 patent;
    we reverse the district court’s denial of JMOL of inva-
    lidity as to claim 7 of the self-test ’460 patent;
    we reverse the district court’s denial of JMOL of inva-
    lidity as to claim 43 of the self-test ’374 patent;
    we affirm the district court’s denial of JMOL of inva-
    lidity as to claims 42 and 67–68 of the self-test ’374 pa-
    tent;
    46                               KONINKLIJKE PHILIPS N.V. v.
    ZOLL MEDICAL CORPORATION
    we affirm the district court’s denial of JMOL of no di-
    rect infringement as to claim 51 of the ’454 waveform
    patent and claims 4 and 8 of the ’905 waveform patent;
    we affirm the district court’s denial of JMOL of no di-
    rect infringement as to claims 1 and 5 of the ’212 wave-
    form patent;
    we affirm the district court’s denial of JMOL of no di-
    rect infringement as to claims 42 and 67–68 of the ’374
    self-test patent;
    we reverse the district court’s denial of JMOL of con-
    tributory infringement as to claims 42 and 67–68 of the
    ’374 self-test patent;
    we affirm the district court’s denial of JMOL of con-
    tributory infringement as to claim 51 of the ’454 wave-
    form patent and claims 4 and 8 of the ’905 waveform
    patent;
    we affirm the district court’s denial of JMOL of inva-
    lidity for indefiniteness for claims 1, 8–9, 11–12, 19, and
    24–25 of the ’526 patent;
    we reverse the district court’s denial of a new trial on
    invalidity for indefiniteness for claims 1, 8–9, 11–12, 19,
    and 24–25 of the ’526 patent;
    we vacate the jury verdict of no invalidity for claims 1,
    8–9, 11–12, 19, and 24–25 of the ’526 patent;
    we remand the case for a new trial on invalidity for
    claims 1, 8–9, 11–12, 19, and 24–25 of the ’526 patent;
    we affirm the district court’s denial of a new trial
    based on exclusion of the Physio-Control 510(k) applica-
    tion evidence;
    we vacate the district court’s denial of a new trial
    based on exclusion of the Marquette electrode device
    evidence; and
    KONINKLIJKE PHILIPS N.V. v.                            47
    ZOLL MEDICAL CORPORATION
    we remand to the district court for a determination of
    whether the testimony as to the Marquette electrode is
    sufficiently corroborated to proceed in a new invalidity
    trial.
    AFFIRMED-IN-PART, REVERSED-IN-PART,
    VACATED-IN-PART, AND REMANDED
    COSTS
    No costs.