  United States Court of Appeals
      for the Federal Circuit
                 ______________________

       LIGHTING BALLAST CONTROL LLC,
               Plaintiff-Appellee

                            v.

    PHILIPS ELECTRONICS NORTH AMERICA
               CORPORATION,
                  Defendant

  UNIVERSAL LIGHTING TECHNOLOGIES, INC.,
             Defendant-Appellant
            ______________________

                       2012-1014
                 ______________________

   Appeal from the United States District Court for the
Northern District of Texas in No. 09-CV-0029, Judge Reed
O’Connor.
                 ______________________

                 Decided: June 23, 2015
                 ______________________

   JONATHAN TAD SUDER, Friedman, Suder & Cooke,
Fort Worth, TX, for plaintiff-appellee. Also represented by
DAVID ARTHUR SKEELS; ROBERT GREENSPOON, Flachsbart
& Greenspoon, LLC, Chicago, IL; ANDREW JOHN DHUEY,
Berkeley, CA.

   STEVEN J. ROUTH, Orrick, Herrington & Sutcliffe LLP,
Washington, DC, for defendant-appellant. Also represent-
2     LIGHTING BALLAST CONTROL LLC   v. PHILIPS ELECTRONICS
                                            NORTH AMERICA


ed by STEN JENSEN, T. VANN PEARCE, JR., DIANA M. SZEGO;
JOHN R. INGE, Tokyo, Japan.

   LEONARD AGNETA, University of Maine School of Law,
Portland, ME, for amicus curiae University of Maine
School of Law, dba Maine Patent Program.

    GEORGE C. SUMMERFIELD, JR., Stadheim & Grear,
Ltd., Chicago, IL, for amici curiae Wisconsin Alumni
Research Foundation, Nutech Ventures, Inc., STC.UNM,
Unemed Corporation, Telecommunications Research
Laboratories, dba TR Tech, Rensselaer Polytechnic Insti-
tute, Tec Edmonton, The Public Patent Foundation. Also
represented by ROLF STADHEIM.

    MAXIM H. WALDBAUM, Eaton & Van Winkle LLP, New
York, NY, for amicus curiae Federation Internationale
Des Conseils En Propriete Industrielle. Also represented
by ROBERT KATZ, Katz PLLC, Dallas, TX.

    ANDY IVAN NIRANJAN COREA, St. Onge Steward John-
ston & Reens, LLC, Stamford, CT, for amicus curiae
Connecticut Intellectual Property Law Association. Also
represented by STEPHEN PATRICK MCNAMARA, TODD M.
OBERDICK.

   WILLIAM LARRY RESPESS, Sheppard, Mullin, Richter &
Hampton LLP, San Diego, CA, for amicus curiae The San
Diego Intellectual Property Law Association.

    JOSEPH R. RE, Knobbe, Martens, Olson & Bear, LLP,
Irvine, CA, for amicus curiae Federal Circuit Bar Associa-
tion. Also represented by SHEILA N. SWAROOP; JOSEPH M.
REISMAN, San Deigo, CA; TERENCE PATRICK STEWART,
Stewart & Stewart, Washington, DC.
LIGHTING BALLAST CONTROL LLC   v. PHILIPS ELECTRONICS   3
NORTH AMERICA


    JANET BETH LINN, Eckert Seamans Cherin & Mellott,
LLC, White Plains, NY, for amicus curiae The Association
of the Bar of the City of New York.

    CHARLES W. SHIFLEY, Banner & Witcoff, Ltd., Chica-
go, IL, for amicus curiae Intellectual Property Law Asso-
ciation of Chicago.

    JOHN W. SHAW, Shaw Keller LLP, Wilmington, DE,
for amicus curiae Delaware Chapter of the Federal Bar
Association. Also represented by KAREN E. KELLER.

    CHARLES HIEKEN, Fish & Richardson, P.C., Boston,
MA, for amicus curiae Paul R. Michel. Also represented
by JOHN A. DRAGSETH, Minneapolis, MN.

   CHIDAMBARAM SUBRAMANIAN IYER, Sughrue Mion,
PLLC, Washington, DC, for amicus curiae Sigram
Schindler Beteiligungsgesellschaft MBH.

   JENNIFER KUHN, Law Office of Jennifer Kuhn, Austin,
TX, for amicus curiae Austin Intellectual Property Law
Association. Also represented by ADEN M. ALLEN, Wilson,
Sonsini, Goodrich & Rosati, PC, Austin, TX.

    HARRY C. MARCUS, Locke Lord, LLP, New York, NY,
for amicus curiae American Intellectual Property Law
Association. Also represented by ROBERT K. GOETHALS;
JOSEPH ANTHONY FARCO, Locke Lord, Bissell & Liddell,
LLP, New York, NY; JEFFREY I.D. LEWIS, Fried, Frank,
Harris, Shriver & Jacobson LLP, New York, NY.

    LAUREL G. BELLOWS, Bellows and Bellows, P.C., Chi-
cago, IL, for amicus curiae American Bar Association.
Also represented by ROBERT FRANCIS ALTHERR, JR., PAUL
MICHAEL RIVARD, Banner & Witcoff, Ltd., Washington,
DC.
4     LIGHTING BALLAST CONTROL LLC   v. PHILIPS ELECTRONICS
                                            NORTH AMERICA


    JOHN D. VANDENBERG, Klarquist Sparkman, LLP,
Portland, OR, for amicus curiae Microsoft Corporation.
Also represented by ANDREW M. MASON.

    THOMAS G. HUNGAR, Gibson, Dunn & Crutcher LLP,
Washington, DC, for amici curiae Cisco Systems, Inc.,
Dell Inc., EMC Corporation, Intel Corporation, SAP
America, Inc., SAS Institute Inc. Also represented by
MATTHEW D. MCGILL; ALEXANDER N. HARRIS, San Fran-
cisco, CA.

    R. CARL MOY, William Mitchell College of Law, St.
Paul, MN, for amicus curiae Intellectual Property Insti-
tute of the William Mitchell College of Law.

    DARYL JOSEFFER, King & Spalding LLP, Washington,
DC, for amici curiae Google Inc., Amazon.com, Inc.,
Hewlett-Packard Company, Red Hat, Inc., Yahoo! Inc.
Also represented by ADAM CONRAD, Charlotte, NC.

    NATHAN K. KELLEY, Office of the Solicitor, United
States Patent and Trademark Office, Alexandria, VA, for
amicus curiae United States. Also represented by ROBERT
J. MCMANUS, KRISTI L. R. SAWERT; MARK R. FREEMAN,
SCOTT R. MCINTOSH, Appellate Staff, Civil Division,
United States Department of Justice, Washington, DC.

    PAUL H. BERGHOFF, McDonnell, Boehnen, Hulbert &
Berghoff, LLP, Chicago, IL, for amicus curiae Intellectual
Property Owners Association. Also represented by
CHRISTOPHER D. BUTTS; RICHARD F. PHILLIPS, ExxonMobil
Chemical Company, Houston, TX; KEVIN H. RHODES, 3M
Innovative Properties Company, St. Paul, MN; HERBERT
CLARE WAMSLEY, JR., Intellectual Property Owners Asso-
ciation, Washington, DC.
LIGHTING BALLAST CONTROL LLC      v. PHILIPS ELECTRONICS   5
NORTH AMERICA


    ROGER LEE COOK, Kilpatrick Townsend & Stockton
LLP, San Francisco, CA, for amicus curiae Ad Hoc Com-
mittee of Patent Owners.

   PETER S. MENELL, University of California Berkeley
School of Law, Berkeley, CA, for amicus curiae Peter S.
Menell.
                ______________________

 Before LOURIE, O’MALLEY, and REYNA, Circuit Judges. 1
REYNA, CIRCUIT JUDGE.
    This case returns to us on remand from the Supreme
Court of the United States and was returned to the panel
for reconsideration in light of Teva Pharmaceuticals USA,
Inc. v. Sandoz, Inc., 574 U.S. ___, 135 S. Ct. 831 (2015).
Appellant Universal Lighting Technologies, Inc. (“ULT”)
appeals four issues. We affirm.
                              I
           A. BACKGROUND OF THE TECHNOLOGY
    High levels of current are required to cause a fluores-
cent lamp to emit visible light. As the panel explained in
the initial panel opinion in this case, Lighting Ballast
Control LLC v. Philips Elecs. N. Am. Corp. (“Lighting
Ballast I”), 498 Fed. App’x 986 (Fed. Cir. 2013), fluores-
cent lamp fixtures typically include an electronic ballast
to regulate electric current flow. An electronic ballast is a
device that maintains current levels high enough to start
the lamp but that prevents current from reaching de-
structive levels. When a lamp is removed from its holders
or when a filament is broken, current provided by the



    1   Pursuant to Fed. Cir. Internal Operating Proce-
dure 15 ¶ 2(b)(ii), Circuit Judge Lourie was designated to
replace Randall R. Rader, now retired, on this panel.
6     LIGHTING BALLAST CONTROL LLC    v. PHILIPS ELECTRONICS
                                              NORTH AMERICA


ballast suddenly ceases to flow through the lamp and
dissipates back into the ballast circuitry. The dissipated
current can destroy the ballast and create an electric
shock hazard for someone servicing the lamp.
    U.S. Patent No. 5,436,529 (“the ’529 patent”), as-
signed to Lighting Ballast LLC (“Lighting Ballast”),
discloses an electronic ballast with the ability to shield
itself from destructive levels of current when a lamp is
removed or becomes defective. ’529 patent col. 2 ll. 39-47.
    Claim 1 recites:
    1. An energy conversion device employing an oscil-
        lating resonant converter producing oscilla-
        tions, having DC input terminals producing a
        control signal and adapted to power at least
        one gas discharge lamp having heatable fila-
        ments, the device comprising:
    voltage source means providing a constant or vari-
       able magnitude DC voltage between the DC
       input terminals;
    output terminals connected to the filaments of the
       gas discharge lamp;
    control means capable of receiving control signals
       from the DC input terminals and from the res-
       onant converter, and operable to effectively ini-
       tiate the oscillations, and to effectively stop the
       oscillations of the converter; and direct current
       blocking means coupled to the output termi-
       nals and operable to stop flow of the control
       signal from the DC input terminals, whenever
       at least one gas discharge lamp is removed
       from the output terminals or is defective.
’529 patent col. 11 ll. 49-68 (emphasis added to relevant
terms).
LIGHTING BALLAST CONTROL LLC   v. PHILIPS ELECTRONICS      7
NORTH AMERICA


                 B. PROCEDURAL HISTORY
    On February 24, 2009, Lighting Ballast filed suit
against ULT asserting infringement of the ’529 patent.
The parties engaged in claim construction briefing and
the court held a hearing thereon. ULT argued that the
term “voltage source means” is governed by 35 U.S.C.
§ 112 ¶ 6 and that the claims are invalid under 35 U.S.C.
§ 112 ¶ 2 as indefinite because the specification fails to
disclose what structure corresponded to the “voltage
source means” limitation. The district court initially
agreed with ULT.
    Lighting Ballast filed a motion for reconsideration.
The district court reversed course, finding that its initial
construction of “voltage source means” was incorrect. The
district court noted that its prior ruling “unduly discount-
ed the unchallenged expert testimony” and “exalted form
over substance and disregarded the knowledge of a person
of ordinary skill in the art.” Lighting Ballast Control,
LLC v. Philips Elecs. N. Am. Corp., No. 7:09-CV-29, 2010
WL 4946343, at *12 (N.D. Tex. Dec. 2, 2010). The district
court cited testimony from an expert for Lighting Ballast,
Dr. Victor Roberts, and the inventor, Andrzej Bobel, both
of whom testified that one of skill in the art would under-
stand the claimed “voltage source means” to correspond to
a rectifier, which converts alternating current (“AC”) to
direct current (“DC”), or other structure capable of supply-
ing useable voltage to the device. Thus, the district court
concluded that the term “voltage source means” had
sufficient structure to avoid the strictures of § 112 ¶ 6 and
denied ULT’s motion.
    Thereafter, ULT renewed its argument that the as-
serted claims are invalid as indefinite, this time couched
as a motion for summary judgment. J.A. 62. The district
court noted that “ULT presents no additional basis for
holding the asserted claims invalid.” Id. The district
court, thus, declined to revisit the issue for a third time
8     LIGHTING BALLAST CONTROL LLC    v. PHILIPS ELECTRONICS
                                             NORTH AMERICA


and adopted its prior findings and analysis regarding the
definiteness of the asserted claims. Id.
    Starting on June 13, 2011, the district court held a ju-
ry trial on the issue of whether ULT’s accused lighting
ballast products infringe claims 1, 2, and 5 of the ’529
patent. The jury returned a verdict finding the ’529
patent valid and infringed and awarded $3 million in
damages to Lighting Ballast.
    ULT moved for judgment as a matter of law (“JMOL”)
on three grounds, as relevant to this appeal: 1) the record
does not contain legally sufficient evidence that the
accused ULT products meet the “direct current blocking
means” limitation of claim 1 of the ’529 patent; 2) the
record does not contain legally sufficient evidence that the
accused ULT products meet the “connected to” limitation
of claim 1 of the ’529 patent; 3) the record does not con-
tain legally sufficient evidence that the accused products
meet the “control means” limitation. The district court
denied the relevant portions of ULT’s JMOL. ULT ap-
pealed.
    After an initial panel decision reversing the judgment
of the district court regarding indefiniteness of the assert-
ed claims based on the “voltage source means” limitation,
Lighting Ballast I, this court granted Lighting Ballast’s
petition for rehearing en banc, Lighting Ballast Control
LLC v. Philips Elecs. N. Am. Corp., 500 Fed. App’x 951
(Fed. Cir. 2013), in order to reconsider the holding in
Cybor Corp. v. FAS Technologies, Inc., 138 F.3d 1448
(Fed. Cir. 1998) (en banc), establishing the standard of
appellate review of district court claim construction
decisions. The case was heard en banc on September 13,
2013. The court issued an opinion affirming that claim
construction is an issue of law that this court reviews de
novo. Lighting Ballast Control LLC v. Philips Elecs. N.
Am. Corp. (“Lighting Ballast II”), 744 F.3d 1272 (Fed. Cir.
LIGHTING BALLAST CONTROL LLC   v. PHILIPS ELECTRONICS      9
NORTH AMERICA


2014) (en banc). Lighting Ballast filed a petition for a
writ of certiorari with the Supreme Court.
    Before the Supreme Court acted on the petition, it is-
sued an opinion in Teva Pharmaceuticals USA, Inc. v.
Sandoz, Inc., 574 U.S. ___, 135 S. Ct. 831 (2015). In that
case, the Supreme Court reversed a decision from this
court, holding that while the ultimate question of the
proper construction of a claim is a legal question that this
court reviews de novo, there may be underlying “subsidi-
ary” factual findings by the district court related to the
extrinsic record that are reviewed for clear error. The
Supreme Court held that this conclusion flows from Rule
52 of the Federal Rules of Civil Procedure and the Su-
preme Court’s prior opinions, such as Markman v.
Westview Instruments, Inc., 517 U.S. 370 (1996).
    Thereafter the Supreme Court granted Lighting Bal-
last’s petition for a writ of certiorari, vacated the en banc
opinion, and remanded it to this court for further consid-
eration in light of Teva.
                             II
               A. “VOLTAGE SOURCE MEANS”
    As noted above, the district court initially construed
the “voltage source means” limitation in claim 1 of the
’529 patent as a means-plus-function limitation. Based on
this conclusion, the court looked for a disclosed structure
in the specification to correspond to the voltage source
function, but found none. These combined conclusions
rendered the patent invalid as indefinite. After Lighting
Ballast filed a motion for reconsideration, the district
court reversed course, finding that its initial construction
of “voltage source means” was incorrect. The district
court noted that its prior ruling “unduly discounted the
unchallenged expert testimony” and “exalted form over
substance and disregarded the knowledge of a person of
ordinary skill in the art.” Lighting Ballast Control, LLC
10    LIGHTING BALLAST CONTROL LLC   v. PHILIPS ELECTRONICS
                                            NORTH AMERICA


v. Philips Elecs. N. Am. Corp., No. 7:09-cv-29, 2010 WL
4946343, at *10, *12 (N.D. Tex. Dec. 2, 2010). The district
court cited testimony from an expert for Lighting Ballast,
Dr. Victor Roberts, and the inventor, Andrzej Bobel, both
of whom testified that one of skill in the art would under-
stand the claimed “voltage source means” to correspond to
a rectifier, which converts alternating current (“AC”) to
direct current (“DC”), or other structure capable of supply-
ing useable voltage to the device. Thus, the district court
concluded that the term “voltage source means” had
sufficient structure to avoid the strictures of § 112 ¶ 6.
The district court reconfirmed this finding when it denied
ULT’s motion for summary judgment of invalidity, ex-
pressly stating it would not consider the question again.
     ULT argues that the district court erred when it held
that the term “voltage source means” is not governed by
§ 112 ¶ 6, both in response to Lighting Ballast’s motion
for reconsideration and in response to ULT’s later motion
for summary judgment. ULT contends that the extrinsic
evidence presented by Lighting Ballast and accepted by
the district court cannot overcome the presumption that
the term is in means-plus-function format for two reasons.
First, ULT believes that Lighting Ballast failed to identify
intrinsic evidence showing that a person of ordinary skill
in the art would understand “voltage source means” to be
structural. Second, ULT contends that, at best, “voltage
source means” refers to any structure capable of perform-
ing that function rather than the definite structure of a
rectifier, as employed in ULT’s products. ULT contends
that, because the written description of the specification
fails to disclose structure corresponding to the claimed
function of the “voltage source means” and the extrinsic
evidence offered did not adequately identify a single
structure, the asserted claims are invalid.
    Citing Rule 51 of the Federal Rules of Civil Procedure,
Lighting Ballast argues that ULT waived any argument
regarding the proper construction of “voltage source
LIGHTING BALLAST CONTROL LLC   v. PHILIPS ELECTRONICS    11
NORTH AMERICA


means” by failing to raise the issue in either its pre- or
post-verdict motions for judgment as a matter of law.
Lighting Ballast also argues that Ortiz v. Jordan, 562
U.S. 180 (2011), prevents ULT from appealing the denial
of ULT’s summary judgment motion regarding indefinite-
ness because Ortiz forbids a party from appealing from an
order denying summary judgment after a full trial on the
merits. In the alternative, Lighting Ballast argues that
the district court’s construction was correct because this
court’s precedent allows “use of even purely functional
claim language to show that the limitation as a whole
suggests structure.” Appellee’s Resp. Br. at 40. Lighting
Ballast contends that a person of ordinary skill in the art
would immediately recognize the implicit disclosure of a
rectifier in the “voltage source means” limitation. Light-
ing Ballast concludes that ULT cannot show clear error in
the district court’s consideration of the extrinsic evidence
in reaching the conclusion that ULT failed to meet its
burden to prove the ’529 patent invalid as indefinite.
    As a preliminary matter, we reject Lighting Ballast’s
argument that ULT waived its argument regarding
“voltage source means” because ULT was not required to
object to claim construction under Rule 51 after ULT
made its claim construction position clear to the court and
the court rejected it. We disagree that Ortiz v. Jordan
controls here. Ortiz addressed a circumstance in which a
trial court denied summary judgment on grounds that
material issues of fact prevented judgment as a matter of
law. In those circumstances, the defendant remained
obliged to present its argument to the trier of fact and
failure to do so prevented raising it on appeal. While the
third and final time the district court addressed the issue
of indefiniteness based on the term “voltage source
means” was in the context of summary judgment, the
issue of whether a claim term is governed by § 112 ¶ 6 is a
claim construction issue. Personalized Media Commc’n,
LLC v. Int’l Trade Comm’n, 161 F.3d 696, 702 (Fed. Cir.
12    LIGHTING BALLAST CONTROL LLC    v. PHILIPS ELECTRONICS
                                             NORTH AMERICA


1998) (“[w]hether certain claim language invokes 35
U.S.C. § 112, ¶ 6 is an exercise in claim construction”); see
also Robert Bosch, LLC v. Snap-On Inc., 769 F.3d 1094,
1098 (Fed. Cir. 2014) (“[d]etermining whether certain
claim language invokes § 112, ¶ 6 is an exercise in claim
construction”) (internal quotations omitted). And claim
construction is an issue for the court, not the jury.
Markman v. Westview Instruments, Inc., 517 U.S. 370,
391 (1996). When the district court denied ULT’s motion
for summary judgment, it did not conclude that issues of
fact precluded judgment; it effectively entered judgment
of validity to Lighting Ballast.
    We conclude that ULT did not waive its argument
that the asserted claims are invalid for indefiniteness. It
is generally accepted that a district court’s claim construc-
tion order is within the class of decisions that do not
terminate litigation and yet may be appealed upon resolu-
tion of the case and issuance of a final judgment. See, e.g.,
O2 Micro Int’l Ltd. v. Beyond Innovation Tech. Co., 521
F.3d 1351, 1359 (Fed. Cir. 2008) (holding that under Fifth
Circuit law the appellants’ arguments on appeal regard-
ing claim construction were not waived even though
appellants did not object to the jury instructions because
the arguments were made clear to the district court and
the district court did not clearly indicate that it was open
to changing its claim construction) (citation omitted); Creo
Prod., Inc. v. Presstek, Inc., 305 F.3d 1337, 1346 (Fed. Cir.
2002) (finding that party preserved its indefiniteness
argument regarding the application of § 112 ¶ 6 for appeal
because the district court resolved the issue prior to
appeal). As ULT points out in its brief, ULT argued
before the district court that the asserted claims were
indefinite under § 112 ¶ 2 because the term “voltage
source means” was governed by § 112 ¶ 6 and lacked
corresponding structure in the written description. The
district court addressed this issue during claim construc-
tion proceedings. The district court initially accepted
LIGHTING BALLAST CONTROL LLC   v. PHILIPS ELECTRONICS    13
NORTH AMERICA


ULT’s position, J.A. 804-15, reversed itself thereafter,
id. at 16-24, and declined to resolve the issue a third time
when ULT moved for summary judgment on this issue,
id. at 62. This is sufficient to preserve the issue for
appeal.
    Rule 51 does not change this result where a party’s
position on claim construction is made clear before the
district court and the district court has rejected that
position. See Taita Chem. Co., Ltd. v. Westlake Styrene,
LP, 351 F.3d 663, 667-68 (5th Cir. 2003) (stating that a
party may be excused from objecting to a jury charge
under Rule 51 of the Federal Rules of Civil Procedure
where the party’s position is clear from the record and the
district court made clear that a further objection would be
unavailing, such as where a party previously filed objec-
tions and the district court made clear no more objections
would be heard); Lang v. Texas & P. Ry. Co., 624 F.2d
1275, 1279 (5th Cir. 1980) (“[Rule 51 of the Federal Rules
of Civil Procedure] is not without exceptions, [ ] and the
failure to object [to the jury charge] may be disregarded if
the party’s position has previously been made clear to the
court and it is plain that a further objection would have
been unavailing.”); see also Cardiac Pacemakers, Inc. v.
St. Jude Medical, Inc., 381 F.3d 1371, 1381 (Fed. Cir.
2004) (“When the claim construction is resolved pre-trial,
and the patentee presented the same position in the
Markman proceeding as is now pressed, a further objec-
tion to the district court’s pre-trial ruling may indeed
have been not only futile but unnecessary. . . . Objection
under Rule 51 [of the Federal Rules of Civil Procedure]
was not required to preserve the right to appeal the
Markman ruling.”) (under Seventh Circuit law). ULT was
not required to object to the jury instructions to preserve
this issue for appeal because it made clear to the district
court its position on the issue and the issue was finally
resolved by the district court prior to trial.
14    LIGHTING BALLAST CONTROL LLC    v. PHILIPS ELECTRONICS
                                             NORTH AMERICA


     Having addressed the preliminary issue of waiver, we
now move to the merits. The district court made findings
of fact based on extrinsic evidence. See Teva, 574 U.S. at
___, 135 S. Ct. at 842. Under the circumstances, it was
not legal error for the district court to rely on extrinsic
evidence, because the extrinsic evidence was “not used to
contradict claim meaning that is unambiguous in light of
the intrinsic evidence.” Phillips v. AWH Corp., 415 F.3d
1303, 1324 (Fed. Cir. 2005). For example, the district
court determined that “while the ‘voltage source means’
term does not denote a specific structure, it is neverthe-
less understood by persons of skill in the lighting ballast
design art to connote a class of structures, namely a
rectifier, or structure to rectify the AC power line into a
DC voltage for the DC input terminals.” J.A. 22. The
district court went on to note that the language following
“voltage source means” in the claim—“providing a con-
stant or variable magnitude DC voltage between the DC
input terminals”—“when read by one familiar with the
use and function of a lighting ballast, such as the one
disclosed by the 529 Patent, [sic] would understand a
rectifier is, at least in common uses, the only structure
that would provide ‘a constant or variable magnitude DC
voltage’”. Id. at 23. The district court further noted that
“[i]t is clear to one skilled in the art that to provide a DC
voltage when the source is a power line, which provides
an AC voltage, a structure to rectify the line is required
and is clear from the language of the ‘voltage source
means’ term.” Id. We defer to these factual findings,
absent a showing that they are clearly erroneous.
    The district court’s factual findings are supported by
the record. Specifically, these factual findings are sup-
ported by the testimony of Dr. Roberts and Mr. Bobel.
Mr. Bobel testified in his deposition that the “voltage
source means” limitation connotes a rectifier to one
skilled in the art. Mr. Bobel further explained that a
battery could likewise provide the necessary DC supply
LIGHTING BALLAST CONTROL LLC   v. PHILIPS ELECTRONICS    15
NORTH AMERICA


voltage described in the patent. Similarly, Dr. Roberts
explained that the “voltage source means” limitation
suggests to him a sufficient structure, or class of struc-
tures, namely a rectifier if converting AC from a “power
line source” to DC for a “DC supply voltage” or a battery if
providing the DC supply voltage directly to the DC input
terminals. This expert testimony supports a conclusion
that the limitations convey a defined structure to one of
ordinary skill in the art. See Rembrandt Data Techs., LP
v. AOL, LLC, 641 F.3d 1331, 1341 (Fed. Cir. 2011).
Because the district court’s factual findings demonstrate
that the claims convey sufficient structure, the district
court was correct to conclude that the term “voltage
source means” is not governed by § 112 ¶ 6. As such, we
affirm the district court’s decision concerning “voltage
source means.”
          B. “DIRECT CURRENT BLOCKING MEANS”
    The district court initially construed the term “direct
current blocking means” to be governed by § 112 ¶ 6. The
district court then determined that a capacitor or diode
was the disclosed corresponding structure. The district
court later amended this construction to indicate that this
term requires that each set of output terminals be con-
nected to a DC blocking capacitor. J.A. 58.
    ULT argues that the district court erred when it
modified its construction of the “direct current blocking
means” term by improperly adding a requirement that
each set of output terminals be connected to a DC block-
ing capacitor. ULT argues that without this limitation on
the claim, it is clear that the asserted claims are antici-
pated by two prior art references: JP 1-157099 (“JP ’099”)
and JP 61-153997 (“JP ’997”).
   Lighting Ballast counters that ULT failed to preserve
any issues related to JP ’099 for appeal by not raising
16       LIGHTING BALLAST CONTROL LLC   v. PHILIPS ELECTRONICS
                                               NORTH AMERICA


JP ’099 before the jury. Lighting Ballast also contends
that ULT’s arguments fail on the merits. 2
    As noted above, where the issue raised in a motion for
summary judgment is a pure question of law or, as in the
case of claim construction, an issue for the court to decide,
the denial of a party’s motion for summary judgment
generally results in a reciprocal grant of summary judg-
ment to the other party. For issues of fact like anticipa-
tion, on the other hand, the denial of a motion for
summary judgment usually only indicates that there are
questions of fact to be resolved. In this case, the parties
treated the district court’s denial of ULT’s motion for
summary judgment of invalidity as though it was a grant
of a motion for summary judgment of no anticipation
based on JP ’099, see J.A. 5234, even though no such
motion was ever filed. Anticipation is a question of fact
that is ultimately for the jury to decide. While ULT
argues it could not have prevailed on its anticipation
defense if operating under the district court’s amended
claim construction, we have no factual record upon which
to assess that argument. We conclude that, absent a
stipulation between the parties regarding anticipation,
ULT had to present the question to the jury in order to
preserve its right to raise it before us.
    We turn to the issue of anticipation by JP ’997. The
district court construed “direct current blocking means” as
requiring a capacitor or diode at every output terminal.
Because JP ’997 does not disclose a capacitor or diode at
every output terminal, the district court concluded that a


     2 Lighting Ballast also makes a summary argument
without citation that ULT waived any arguments regard-
ing dependent claims 2 and 5 by failing to appeal the
judgment of validity of these claims. We decline to ad-
dress this arguments given the insufficient explanation
and lack of legal basis supporting the argument.
LIGHTING BALLAST CONTROL LLC   v. PHILIPS ELECTRONICS    17
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material fact existed as to whether JP ’997 anticipates the
claims. The parties disputed the issue at trial, and the
jury returned a verdict of no anticipation.
    The parties agree that the term “direct current block-
ing means” is governed by § 112 ¶ 6. The parties also
agree that the corresponding structure is a collection of
capacitors or diodes. The only point of disagreement is
whether the structure requires a capacitor/diode coupled
to every set of output terminals or only those through
which the DC control signal passes and whether, under
the correct construction, JP ’997 anticipates the asserted
claims.
    ULT has failed to show reversible error in the district
court’s construction of the term “direct current blocking
means.” Claim 1 recites “output terminals” and a “direct
current blocking means coupled to the output termi-
nals . . . .” The plain language of the claims requires a
direct current blocking means at every output terminal.
Under the district court’s construction, the jury’s verdict
is supported by substantial evidence. At trial, Dr. Zane
testified that JP ’997 does not teach a DC blocking means
attached to each of the output terminals. J.A. 13340-41.
Dr. Giesselmann failed to offer any testimony regarding
structural equivalency. As such, we hold that the district
court’s construction of “direct current blocking means”
was not erroneous, and that the jury’s verdict of no antic-
ipation is supported by substantial evidence.
              C. “WHENEVER . . . DEFECTIVE”
    We turn to the construction of “whenever at least one
discharge lamp is removed from the output terminals or is
defective.” The “direct current blocking means” recited in
claim 1 is “operable to stop flow of the control signal from
the DC input terminals, whenever at least one gas dis-
18       LIGHTING BALLAST CONTROL LLC   v. PHILIPS ELECTRONICS
                                               NORTH AMERICA


charge lamp . . . is defective.” 3 The district court con-
strued “defective” to mean “whenever the direct current
path between [two terminals] is broken.” A51. The court
relied on the following language in the specification for
support: “the [direct current blocking means] will be held
discharged for any period of time as long as: (i) there is an
unbroken direct current path DCP between terminal B+
and terminal CTa . . . .”
     The district court’s construction is supported by the
intrinsic record. The DC blocking means does not block
control signal when a lamp is inserted into its holders and
has a working filament. There is no need to block current
in this instance because the circuit is closed, and there is
no danger that current will dissipate into the ballast
circuitry. As the district court recognized, on the other
hand, the DC blocking means blocks control signal when a
lamp is removed or when the lamp has a broken filament,
i.e., when the direct current path between the relevant
terminals (terminals B+ and CTa) is broken. As a result,
the district court’s claim construction was not erroneous.
                     D. “CONNECTED TO”
     Before trial, the parties did not propose that the dis-
trict court construe the term “connected to.” ULT did not
ask for its proposed construction until after trial. In
resolving ULT’s motion for JMOL, the district court
construed the term to mean the same thing as “for con-
nection to.”
    ULT argues that its accused products do not include
“output terminals connected to the filaments” of a lamp as
required by claims 1, 2, and 5 because the term means
something different from “for connection to.” Lighting


     3    Lighting Ballast argues that ULT waived “when-
ever . . . defective” arguments. We reject that argument
for the reasons given in Part II.A of this opinion.
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Ballast argues that ULT waived this argument.           We
agree.
     ULT waived its right to seek a new claim construction
because ULT did not seek that construction until after
trial. As in Broadcom Corp. v. Qualcomm Inc. this case
“falls squarely within our holding in Eli Lilly & Company
v. Aradigm Corporation, where a party ‘never requested
that the district court construe any terms in the relevant
claim and never offered a construction of that claim, but
rather only after the presentation of all of the evidence to
the jury . . . even suggested that claim construction
might be helpful to determine the proper scope of the
claimed invention.’” 543 F.3d 683, 694 (Fed. Cir. 2008)
(quoting Eli Lilly, 376 F.3d 1352, 1360 (Fed. Cir. 2004)
(internal quotations and brackets omitted)). We hold that
ULT has waived its right to request a construction of
“connected to” and that ULT implicitly conceded that the
meanings of “connected to” is clear and not in need of
construction.
                   E. “CONTROL MEANS”
    ULT argues that the district erred in denying JMOL
on the basis of infringement of the “control means” limita-
tion under the doctrine of equivalents. ULT contends that
it does not infringe the asserted claims because the con-
trol circuits in the accused products allow a ballast to
continue to draw power after shutdown, a feature that
differentiates the accused products from the “control
means” limitation of claim 1. According to ULT, the ’529
patent disclaims circuits like the accused circuits that
draw power after shutdown by distinguishing such cir-
cuits from the “control means” feature. ULT also high-
lights a number of other ways in which ULT’s products
differ from the “control means” limitation of claim 1.
   Lighting Ballast counters that substantial evidence
supports the jury’s finding of equivalency. According to
Lighting Ballast, claim 1 does not require the absence of
20    LIGHTING BALLAST CONTROL LLC   v. PHILIPS ELECTRONICS
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power-draw from the ballast on shutdown. Rather, Light-
ing Ballast explains that the “control means” feature
must be operable to stop oscillations of the converter, a
feature that Lighting Ballast contends the accused prod-
ucts share with embodiments of the ’529 Patent. Lighting
Ballast argues that ULT confuses power draw from the
ballast with stopping oscillations of the converter. Ac-
cordingly, Lighting Ballast contends that because ULT
does not challenge the jury’s implicit finding that the
accused products stop oscillations of the converter, the
jury’s verdict is supported by substantial evidence. We
agree with Lighting Ballast.
    A denial of a motion for JMOL is not unique to patent
law, and thus, we apply the law of the applicable regional
circuit, in this case the Fifth Circuit. See Transocean
Offshore Deepwater Drilling, Inc. v. Maersk Drilling USA,
Inc., 699 F.3d 1340, 1346-47 (Fed. Cir. 2012). Under Fifth
Circuit law, a district court’s decision on a motion for
JMOL is reviewed de novo, reapplying the JMOL stand-
ard. Ford v. Cimarron Ins. Co., 230 F.3d 828, 830 (5th
Cir. 2000). JMOL is appropriate when a party has been
fully heard on an issue and there is no legally sufficient
evidentiary basis for a reasonable jury to find for that
party on that issue. Fed. R. Civ. P. 50(a)(1).
    ULT seeks to have this court reverse the district
court’s opinion on JMOL regarding the “control means”
term by reweighing the evidence produced at trial. We
refuse to do so. The role of an appellate court is to review
the final judgment issued by the district court. When
final judgment is issued upon a jury verdict, this court
can only look to whether there was substantial evidence
to support the jury’s verdict. We may not independently
reweigh the evidence, as ULT asks this court to do.
    We conclude that the jury’s verdict is supported by
substantial evidence. As outlined in the district court’s
opinion, Lighting Ballast’s expert, Dr. Victor Roberts,
LIGHTING BALLAST CONTROL LLC   v. PHILIPS ELECTRONICS   21
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identified the structure of the accused products and
testified that such structures were equivalent to the
“control means” of the ’529 patent for infringement pur-
poses. Dr. Roberts first identified where DC enters the
“control means” and testified that the accused products
perform the first function of the ’529 patent “control
means” of receiving a control signal from the DC input
terminals. Dr. Roberts then testified that the accused
products satisfy the second function of the “control
means” limitation because they initiate oscillations and
stop oscillations of the converter. Dr. Roberts explained
that the signal flows down through the resistors, through
the discrete transistors and eventually over the integrat-
ed circuit into a pin labeled EN2, which enables oscilla-
tions. Dr. Roberts testified in detail as to the way in
which the accused products meet the “control means”
limitation. We find that this evidence is sufficient to
support the jury’s verdict of infringement.
                           III
     For these reasons, we affirm the judgment of the dis-
trict court.
                      AFFIRMED
