  United States Court of Appeals
      for the Federal Circuit
                ______________________

            EPOS TECHNOLOGIES LTD.,
       Plaintiff/Counterclaim Defendant-Appellee,

                          AND

   DANE-ELEC S.A., DANE-ELEC MEMORY S.A.,
     AND DANE-ELEC CORPORATION USA,
           Counterclaim Defendants,

                           v.

         PEGASUS TECHNOLOGIES LTD.,
         Defendant/Counterclaimant-Appellant,

                          AND

                   LUIDIA, INC.,
              Counterclaimant-Appellant.
               ______________________

                      2013-1330
                ______________________

    Appeal from the United States District Court for the
District of Columbia in No. 07-CV-0416, Judge William M.
Nickerson.
                 ______________________

              Decided: September 5, 2014
                ______________________
2       EPOS TECHNOLOGIES LTD.   v. PEGASUS TECHNOLOGIES LTD.



     DEANNE E. MAYNARD, Morrison & Foerster LLP, of
Washington, DC, argued for plaintiff/counterclaim De-
fendant-appellee. With her on the brief were ANTHONY L.
PRESS, HECTOR G. GALLEGOS, WENDY J. RAY, and
CHRISTIAN G. ANDREU-VON EUW, of Los Angeles, Califor-
nia.

    WILLIAM P. ATKINS, Pillsbury Winthrop Shaw Pittman
LLP, of McLean, Virginia, argued for defend-
ant/counterclaimant-appellant    and   counterclaimant-
appellant. With him on the brief were CHRISTOPHER K.
DORSEY, and A. JOHN DEMARCO, of Washington, DC.
                ______________________

            HUGHES and BRYSON, Circuit Judges. *
HUGHES, Circuit Judge.
    Appellants, Pegasus Technologies Ltd. and Luidia,
Inc., own several patents relating to digital pens and
receiver devices which, they allege, the Appellees have
infringed. Following claim construction of certain terms
in the patents, the district court granted summary judg-
ment of noninfringement in favor of Appellees. Because
we conclude that the district court erred in construing
four claim terms and in granting summary judgment of
noninfringement, we vacate-in-part, reverse-in-part, and
remand for further proceedings consistent with this
opinion.
                             I
    Appellants allege infringement of six patents: U.S.
Patent Nos. 6,266,051; 6,326,565; 6,392,330; 6,501,461;
6,724,371; and 6,841,742. The patents relate to pens that


    *   Randall R. Rader, who retired from the position of
Circuit Judge on June 30, 2014, did not participate in this
decision.
EPOS TECHNOLOGIES LTD.   v. PEGASUS TECHNOLOGIES LTD.     3



digitize writing and devices for retrofitting writing sur-
faces so that writing can be digitally captured. See, e.g.,
’371 patent col. 1 ll. 6–9. The Appellees, EPOS Technolo-
gies Ltd., Dane-Elec S.A., Dane-Elec Memory S.A., and
Dane-Elec Corp. USA (collectively, EPOS), manufacture
and sell products used to digitize writing (EPOS Prod-
ucts). These products include a receiver unit with a
spring-loaded, U-shaped clip-on bracket and a pen refill.
    In 2007, EPOS Technologies Ltd. filed a complaint
against Pegasus Technologies Ltd. seeking declaratory
judgment of noninfringement of the ’565, ’330, ’371, and
’742 patents. Pegasus filed an answer and counterclaims,
adding Luidia, Inc. as a counterclaim plaintiff (collective-
ly, Pegasus). Pegasus also asserted infringement of two
additional patents in its counterclaims, the ’051 and ’461
patents, resulting in a total of six asserted patents. After
claim construction, EPOS moved for summary judgment
of invalidity and noninfringement. The district court
granted the motion and declined to address invalidity in
light of its nonfringement rulings. Pegasus appeals the
district court’s construction of four claim terms and the
district court’s grant of summary judgment of nonin-
fringement.     We have jurisdiction under 28 U.S.C.
§ 1295(a)(1).
                             II
    “Claim construction is a legal statement of the scope
of the patent right” that we review de novo. Lighting
Ballast Control LLC v. Philips Elecs. N. Am. Corp., 744
F.3d 1272, 1276–77, 1284 (Fed. Cir. 2014) (en banc);
Cybor Corp. v. FAS Techs., Inc., 138 F.3d 1448, 1456 (Fed.
Cir. 1998) (en banc). Claim terms are generally given
their ordinary and customary meaning as understood by a
person of ordinary skill in the art. Phillips v. AWH Corp.,
415 F.3d 1303, 1312–13 (Fed. Cir. 2005) (en banc). The
person of ordinary skill in the art is “deemed to read the
claim term not only in the context of the particular claim
4    EPOS TECHNOLOGIES LTD.   v. PEGASUS TECHNOLOGIES LTD.



in which the disputed term appears, but in the context of
the entire patent, including the specification.” Id. at
1313. On the other hand, “it is improper to read limita-
tions from a preferred embodiment described in the
specification—even if it is the only embodiment—into the
claims absent a clear indication in the intrinsic record
that the patentee intended the claims to be so limited.”
Liebel-Flarsheim v. Medrad, Inc., 358 F.3d 898, 913 (Fed.
Cir. 2004). We recognize that “the distinction between . . .
interpret[ing] the meaning of a claim and importing
limitations . . . into the claim can be a difficult one to
apply in practice.” Phillips, 415 F.3d at 1323. Neverthe-
less, “[t]he construction that stays true to the claim lan-
guage and most naturally aligns with the patent’s
description of the invention will be, in the end, the correct
construction.” Id. at 1316 (citation omitted) (quotation
omitted).
    We review a grant of summary judgment under the
law of the regional circuit, here the D.C. Circuit. Charles
Mach. Works, Inc. v. Vermeer Mfg. Co., 723 F.3d 1376,
1378 (Fed. Cir. 2013). The D.C. Circuit reviews a district
court’s grant of summary judgment de novo, Coalition for
Common Sense in Government Procurement v. United
States, 707 F.3d 311, 315 (D.C. Cir. 2013), drawing all
reasonable inferences in favor of the nonmovant, Ander-
son v. Liberty Lobby, Inc., 477 U.S. 242, 255 (1986).
Summary judgment is appropriate when there is “no
genuine dispute as to any material fact and the movant is
entitled to judgment as a matter of law.” Fed. R. Civ. P.
56(a).
    Infringement is a question of fact. Charles Machine,
723 F.3d at 1378. On appeal from a grant of summary
judgment of noninfringement, “we must determine
whether, after resolving reasonable factual inferences in
favor of the patentee, the district court correctly conclud-
ed that no reasonable jury could find infringement.” Id.
(quoting Crown Packaging Tech., Inc. v. Rexam Beverage
EPOS TECHNOLOGIES LTD.   v. PEGASUS TECHNOLOGIES LTD.    5



Can Co., 559 F.3d 1308, 1312 (Fed. Cir. 2009)) (internal
quotation marks omitted).
                            III
    Pegasus appeals the district court’s construction of
“drawing implement” and “given time interval” in the ’565
and ’742 patents, “marking implement” in the ’461 patent,
and “temporary attachment” in the ’051 patent. The
district court erroneously construed these four terms.
Because of the erroneous claim constructions, the district
court erred by granting summary judgment of nonin-
fringement of the ’565, ’742, ’461, and ’051 patents.
                             A
    The ’565 and ’742 patents relate to digitizing writing
on presentation boards. The ’742 patent discloses a
transmitter device for use with conventional writing
implements. ’742 patent abstract, col. 2 ll. 29–41. The
’565 patent addresses data loss caused by a data trans-
mission delay after the end of each pen stroke or resyn-
chronization delay. ’565 patent col. 4 ll. 58–61. According
to the ’565 patent, this delay is particularly problematic
for short strokes because it may cause some of the infor-
mation conveyed by the stroke to not be recorded. ’565
patent col. 4 ll. 54–57. The ’565 patent addresses this
problem by “maintaining synchronization between the
transmitter device 40 and the receiver system for a given
period of time after the end of each pen stroke.” ’565
patent col. 4 ll. 58–61.
    Claim 1 of the ’565 patent and claim 2 of the ’742 pa-
tent are representative. Claim 1 of the ’565 patent re-
cites:
   A transmitter device for use with a system for dig-
   itizing operative strokes of a handheld drawing
   implement, the drawing implement having a body
   and an operative tip, the transmitter device com-
   prising:
6    EPOS TECHNOLOGIES LTD.   v. PEGASUS TECHNOLOGIES LTD.



       a housing;
       a transmitter mounted relative to said
       housing;
       a microswitch that is responsive to a force
       exerted on the operative tip of the draw-
       ing implement towards said housing;
       electronic circuitry responsive to said mi-
       croswitch to affect operation of said
       transmitter, wherein said electronic cir-
       cuitry operates said transmitter for a giv-
       en time interval after said microswitch
       ceases to indicate a force exerted on said
       housing towards the operative tip of the
       drawing implement.
’565 patent col. 6 ll. 34–49 (emphases added). Claim 2 of
the ’742 patent recites:
    A system for digitizing operative strokes of a
    drawing implement comprising a body, a back
    end, and a front end opposite the back end com-
    prising an operative tip, the system comprising:
       at least one ultrasound receiver assembly;
       a housing comprising a substantially cy-
       lindrical opening terminating at a first
       end, and an inner housing surface having
       a central bore, the housing receiving a
       portion of the drawing implement, the op-
       erative tip extending through the central
       bore;
       a retainer attachable to a second end of
       the opening to retain the drawing imple-
       ment within the housing, the retainer hav-
       ing a spring element for biasing the
       drawing implement towards the inner
       housing surface; and
EPOS TECHNOLOGIES LTD.     v. PEGASUS TECHNOLOGIES LTD.          7



        an ultrasound transmitter mounted rela-
        tive to the housing proximal the central
        bore.
’742 patent col. 14 ll. 8–23 (emphases added).
                                1
    The district court construed “drawing implement” as
“a conventional writing utensil that can be used alone or
together with the invention.” EPOS Techs. Ltd. v. Pega-
sus Techs. Ltd., 802 F. Supp. 2d 39, 49 (D.D.C. 2011)
(emphasis added). In doing so, the district court ex-
plained that the language of the claims is “exceedingly
broad,” but that the remainder of the patent is not “so
broad as to contemplate using something like ‘a piece of
charcoal.’” Id. The district court stated that the construc-
tion should recognize that a drawing implement “is a
stand-alone writing utensil, in the sense that it is a
writing utensil that can be used as such.” Id.
     The correct construction of the term “drawing imple-
ment” should include “a writing utensil that can be used
alone or together with the invention.” But the correct
construction also should exclude the word “conventional.”
The claims themselves only state that a drawing imple-
ment must have at least a “body” and an “operative tip.”
’565 patent col. 6 ll. 37; ’742 patent col. 14 ll. 8–10. The
claims do not state that the “drawing implement” must be
“conventional” or exclude a piece of charcoal. Further, the
specifications describe drawing implements of “a range of
lengths and widths” and of “any size or shape.” See, e.g.,
’565 patent col. 4 ll. 15–16, col. 4 ll. 21–22; ’742 patent col.
8 ll. 13–14, col. 8 l. 19. Also, the specifications expressly
disclose a variety of drawing implements such as “conven-
tional writing implements,” a “hand held drawing imple-
ment,” a “dry erase marker,” a “red or blue pen,” and an
“eraser.” See, e.g., ’565 patent col. 2 l. 37, col. 5 l. 56, col. 6
ll. 6–11; ’742 patent col. 3 ll. 30–31.
8    EPOS TECHNOLOGIES LTD.   v. PEGASUS TECHNOLOGIES LTD.



    The district court erred by importing the word “con-
ventional” from preferred embodiments into its construc-
tion of the term. See Liebel-Flarsheim, 358 F.3d at 913.
Although it is true that the specifications recite embodi-
ments including “conventional” writing implements, there
is no clear indication in the intrinsic record suggesting
that the claims are limited to “conventional” drawing
implements. Because the district court erred by including
the word “conventional” in its construction of the term
“drawing implement,” we vacate its construction of the
term.
    The district court determined that because “no rea-
sonable jury could find that pen refills used in the EPOS
Products are ‘drawing implement[s]’ as that term has
been construed, EPOS is entitled to summary judgment.”
EPOS Techs. Ltd. v. Pegasus Techs. Ltd., 916 F. Supp. 2d
88, 93 (D.D.C. 2013). But because the “drawing imple-
ment” need not be “conventional,” the district court erred
by granting summary judgment of noninfringement.
    In considering infringement, a reasonable jury might
find that a pen refill meets the “drawing implement”
limitation as properly construed. For example, a reason-
able jury might find that a pen refill meets the “drawing
implement” limitation because the specifications disclose
that “[t]he invention . . . may be used with replaceable
conventional pen elements.” ’742 patent col. 5 ll. 24–27
(emphasis added); see also ’565 patent col. 3 ll. 17–20.
Moreover, even if the pen refill does not literally satisfy
the claim term, a jury might find infringement on the
basis that a pen refill satisfies this claim limitation under
the doctrine of equivalents. Accordingly, we reverse the
grant of summary judgment of noninfringement.
                             2
    The district court construed “given time interval” as
“fixed at a few seconds or less.” EPOS, 802 F. Supp. 2d at
48. The district court explained that, “while the words of
EPOS TECHNOLOGIES LTD.   v. PEGASUS TECHNOLOGIES LTD.    9



the claims do not limit the time interval, all evidence
suggests there must be some upper-bound to the interval
contemplated by the patentee.” Id. According to the
district court, an upper bound was required because the
patents sought to solve the problem of quick pen strokes
made in rapid succession. Id. The district court found no
evidence that the problem the patents sought to solve
extended to pen strokes made after longer periods of time.
Id.
    The patents do not require an upper bound of “a few
seconds or less” on the “given time interval.” Instead, the
patents describe and claim embodiments with time inter-
vals that can “preferably” or “typically” be used and with
lower-bound time intervals. ’742 patent col. 11 ll. 41–43;
’565 patent col. 5 ll. 2–4, col. 6 ll. 50–51.
    Although the word “given” may indicate that a time
interval is fixed, specified, or predetermined by an opera-
tor or a programmer, the intrinsic evidence does not limit
“given time interval” to “fixed at a few seconds or less.”
By limiting the term “given time interval” to “a few sec-
onds or less,” the district court erroneously imported a
limitation from a preferred embodiment. See Liebel-
Flarsheim, 358 F.3d at 913. Moreover, we have consid-
ered EPOS’s arguments regarding its construction of this
term, including the indefiniteness arguments, and find
them unpersuasive. We thus vacate the district court’s
construction of “given time interval.”
    In light of its claim construction, and because neither
party disputed that the EPOS Products operated for 25
seconds after ceasing to detect input, the district court
determined that EPOS was entitled to summary judg-
ment of noninfringement. EPOS, 916 F. Supp. 2d at 93–
94. The district court’s grant of the motion was in error
because it was based on an improperly limited construc-
tion of “given time interval.” Thus, we reverse the grant
of summary judgment of noninfringement.
10    EPOS TECHNOLOGIES LTD.    v. PEGASUS TECHNOLOGIES LTD.



                               B
      The ’461 patent relates to digital pens that are porta-
ble and usable with any writing surface. ’461 patent col. 3
ll. 20–44. It discloses an “improved fitting technique that
allows rapid and efficient retrofit of a tracking assembly
. . . that accurately tracks a writing implement . . . [and]
captur[es] all marks placed on the marking surface.” ’461
patent col. 3 ll. 37–44. According to the patent, retrofit-
ting is not trivial because of the “difficulty of attaining
accurate tracking of a marking implement to capture
position information that may be converted to a precision
representation of text and drawings.” ’461 patent col. 5 ll.
18–23.
     The patent explains that to improve accuracy, the
marking implement may have a tapered sleeve that
terminates with a switch to detect the movement of a pen
tip when it is placed on the writing surface. ’461 patent
col. 7 ll. 31–38. The switch generates a signal that tracks
the marking implement’s position. ’461 patent col. 7 ll.
39–49. The signal may also identify “a particular mark-
ing implement function or color, for example whether the
marking implement is a red or blue pen, . . . a thin line or
a thick line, or . . . an eraser.” ’461 patent col. 7 ll. 50–55.
   At issue in this appeal is the term “marking imple-
ment.” Claim 1 of the ’461 patent includes the term:
     A retrofittable apparatus for converting a sub-
     stantially planar surface into a writing surface for
     an electronic data capture device, the apparatus
     comprising:
        a unitary sensor array that securely and
        rigidly fixes a relation between a plurality
        of sensors and that provides a tracking
        function to determine the position of a
        marking implement on the writing sur-
        face; and
EPOS TECHNOLOGIES LTD.   v. PEGASUS TECHNOLOGIES LTD.      11



        a means for affixing the unitary sensor ar-
        ray to the substantially planar surface.
’461 patent col. 9 ll. 41–50 (emphasis added). Dependent
claim 12 recites a marking implement comprising “a
sleeve that has an inner diameter that is adapted to
receive and securely retain a standard marker; and a first
switch that detects movement of a marker tip . . . .” ’461
patent col. 10 ll. 27–35.
     The district court construed “marking implement” as
“an implement that has a marker tip (and not a pen tip).”
EPOS, 802 F. Supp. 2d at 50. It determined that, “while
the specifications occasionally reference a ‘pen’ and ‘pen
tip,’ the totality of the specifications makes clear that the
patentee was merely using those terms as synonyms for a
dry-erase marker.” Id. (citing ’461 patent col. 7 ll. 31–37
(“The . . . sleeve . . . has an inner diameter that is adapted
to receive . . . a standard dry-erase marker. Thus, the
herein-disclosed marking implement uses a marker . . . .
The sleeve is tapered to follow the tapered contour of the
pen.”)).
     Nothing in the ’461 patent limits a “marking imple-
ment” to an implement with “a marker tip (and not a pen
tip).” As an initial matter, a pen or pencil—not just a
“marker” or an implement with a “marker tip”—can mark
surfaces. Moreover, the specification interchangeably
refers to a “marking implement” as a “marker” and as a
“pen.” ’461 patent col. 7 ll. 33–38; see also ’461 patent col.
7 ll. 54–55. It also refers to the marking implement’s tip
as a “pen tip.” Id. And it teaches that the marking im-
plement can perform an “eraser function.” ’461 patent col.
10 ll. 46–49. Given these broad disclosures, the district
court erroneously construed “marking implement” to
require a “marker tip” and to exclude implements with a
“pen tip.” Accordingly, we vacate the district court’s
construction of “marking implement.”
12   EPOS TECHNOLOGIES LTD.   v. PEGASUS TECHNOLOGIES LTD.



    The district court granted summary judgment of non-
infringement based on its erroneous construction of the
term, finding that Pegasus “essentially seeks to extend
the Patent to cover that which has been expressly exclud-
ed by the Court’s construction—an implement that has a
pen tip.” EPOS, 916 F. Supp. 2d at 96–97. But because a
“marking implement,” as used in the ’461 patent, neither
is limited to a “marker” nor excludes a “pen tip,” we
reverse the district court’s grant of summary judgment.
                             C
     The ’051 patent is directed to a “graphic data-
acquisition system” with a “retrofittable apparatus for
converting a substantially planar surface into an electron-
ic data capture device.” ’051 patent col. 3 ll. 17–20. The
patent discloses a “fitting technique that allows rapid and
efficient retrofit of a tracking assembly” to a planar
surface, such as a whiteboard. ’051 patent col. 4 ll. 48–55.
This fitting technique “may be any technique or device
that affixes the sensor array to the writing surface.” ’051
patent col. 5 ll. 13–14. Indeed, the patent discloses “a
variety of configurations” for attachment “by providing a
variety of adapters and/or fasteners.” ’051 patent col. 6 ll.
43–50, figs. 2–7.
    Figure 2 of the ’051 patent shows “conventional meth-
ods” like “double stick mounting tape or a temporary
fastener, such as Velcro.” ’051 patent col. 5 ll. 49–54.
Figure 3 shows the sensor array mounted to a wall with a
bracket, which also may be used to secure the writing
surface. ’051 patent col. 5 ll. 60–65. Figure 4 shows a
bracket mounted to a wall, wherein the sensor array has a
complementary channel that slides onto a portion of the
wall-mounted bracket projecting from the wall. ’051
patent col. 6 ll. 1–10. Figure 5 shows a sensor array
affixed to the writing surface with a clip-on bracket “that
includes a U-shaped portion . . . adapted to engage with
EPOS TECHNOLOGIES LTD.   v. PEGASUS TECHNOLOGIES LTD.    13



the upper edge of the writing surface.” ’051 patent col. 6
ll. 13–19.




    The “temporary attachment” limitation in the ’051 pa-
tent is at issue on appeal. Claim 1 is representative and
recites this limitation:
   A retrofittable apparatus adapted for converting a
   substantially planar surface into a writing surface
   for an electronic data capture device, comprising:
       a sensor array . . . ; and
       a temporary attachment for removably af-
       fixing said sensor array proximate to said
       substantially planar surface.
’051 patent col. 10 ll. 2–12 (emphasis added).
14    EPOS TECHNOLOGIES LTD.   v. PEGASUS TECHNOLOGIES LTD.



     The district court construed “temporary attachment”
as “an element that can be removed from the device’s
‘retrofittable apparatus.’” EPOS, 916 F. Supp. 2d at 98.
    On its face, claim 1 requires that the “temporary at-
tachment” is an element of the “retrofittable apparatus.”
So the “temporary attachment” is not something that can
be removed from the retrofittable apparatus. Instead, the
retrofittable apparatus has two components: a sensor
array and a temporary attachment. The attachment is
“temporary” not because the mechanism itself can be
removed from the sensor array, but because it is “for
removably affixing” the sensor array to the board. ’051
patent col. 10 ll. 2–12.
    The specification discloses that a key aspect of the in-
vention is that the sensor array assembly “may be repeat-
edly removed and affixed to any substantially planar
surface.” ’051 patent col. 5 ll. 30–38. Figure 4 teaches a
complementary channel, and figure 5 teaches a clip-on
bracket. ’051 patent col. 6 ll. 6–7, 15–16. Both configura-
tions provide easy and repeatable affixation and removal.
The double-sided tape in figure 2 and the masking tape
embodiments in the prosecution history enable the sensor
array to be affixed to and then removed from the writing
surface. ’051 patent col. 5 ll. 49–54; J.A. 801–802. The
complementary channel, clip-on bracket, and tape are
“temporary attachments” because they provide a mecha-
nism by which the sensor array can be affixed to and
removed from the writing surface repeatedly without
permanently affixing an object to the writing surface.
     The district court’s construction is incorrect because it
reads out preferred embodiments. “[A] claim construction
that excludes a preferred embodiment . . . is rarely, if ever
correct and would require highly persuasive evidentiary
support.” See Anchor Wall Sys., Inc. v. Rockwood Retain-
ing Walls, Inc., 340 F.3d 1298, 1308 (Fed. Cir. 2003)
(citations omitted). Here, the district court’s construction
EPOS TECHNOLOGIES LTD.   v. PEGASUS TECHNOLOGIES LTD.     15



reads out preferred embodiments and it is not supported
by “highly persuasive” evidence. For example, the sensor
array in figure 5 “is affixed to a clip-on bracket.” ’051
patent col. 6 ll. 13–19 (emphasis added). As another
example, the sensor array in figure 4 is “associated
therewith” to a bracket having a complementary channel
to the wall-mounted bracket. ’051 patent col. 6 ll. 1–10.
Thus, we vacate the district court’s construction of “tem-
porary attachment.”
    The district court granted summary judgment of non-
infringement based on its incorrect construction of the
term. EPOS, 916 F. Supp. 2d at 98. The district court
determined that the EPOS Products could not meet the
“temporary attachment” limitation because it was “undis-
puted that the EPOS Products use receiver units
equipped with spring loaded clips . . . , and that those
clips are permanently attached to the receiver units.” Id.
This determination was based on an erroneous construc-
tion. Accordingly, we reverse the district court’s grant of
summary judgment of noninfringement.
                             IV
   Pegasus also appeals the district court’s grant of
summary judgment of noninfringement of the ’371 patent
under the doctrine of equivalents.
    The ’371 patent discloses a housing that surrounds a
drawing implement with an ultrasonic device mounted
“within the housing, remote from the drawing tip, yet in
close proximity . . . [and] the device being for receiving or
transmitting an intermittent ultrasound signal.” ’371
patent col. 2 ll. 47–64. The system may also include an
ultrasonic device for transmitting several intermittent
ultrasound signals, each with a different frequency, for
indicating which of several implements is in use. ’371
patent col. 4 ll. 1–10. Also “the intermittent ultrasound
signals of the different frequency are transmitted by the
transmitting device in a mode dependent manner, thereby
16   EPOS TECHNOLOGIES LTD.   v. PEGASUS TECHNOLOGIES LTD.



informing the processing system whether the operative
tip is in contact with, or removed from, the board or
screen.” ’371 patent col. 4 ll. 32–37. All of the claims at
issue in the ’371 patent claim a handheld device for use
with a board comprising several components, including an
ultrasonic receiver or transmitter device for receiving or
transmitting an “intermittent” ultrasound signal. ’371
patent cols. 22–26 (claims 1–3, 7, 10–12).
    The district court essentially adopted Pegasus’s pro-
posed construction of “intermittent” as “something that
occurs occasionally, in a non-continuous manner, in a
random or unpredictable manner, or at selected times.”
EPOS, 916 F. Supp. 2d at 94–95. The district court stated
that “intermittent” could “refer only to those times when
the user is actively using the device.” Id. Otherwise,
according to the district court, any device using any form
of ultrasound to transmit data would satisfy the limita-
tion. Id. Applying its construction, the district court
determined that “it is clear that EPOS is entitled to
summary judgment on Pegasus’s claim of literal in-
fringement because it is undisputed that the EPOS Prod-
ucts generate a continuous ultrasound signal.” Id. at 95.
Pegasus does not appeal these determinations.
     The district court devoted only two sentences to its
decision on infringement of the ’371 patent under the
doctrine of equivalents. It reasoned that allowing contin-
uous ultrasound signals to be equivalents “would elimi-
nate the intermittent limitation entirely,” and that “the
doctrine of equivalents cannot extend that far.” Id.
(citing Planet Bingo, LLC v. GameTech Int’l, Inc., 472
F.3d 1338, 1344 (Fed. Cir. 2006) and Warner–Jenkinson v.
Hilton Davis Chem. Co., 520 U.S. 17, 29 (1997)).
    When addressing the doctrine of equivalents, a court
must ask whether an asserted equivalent is an “insub-
stantial difference” from the claimed element, or whether
it matches the “function, way, and result of the claimed
EPOS TECHNOLOGIES LTD.   v. PEGASUS TECHNOLOGIES LTD.     17



element.” Deere & Co. v. Bush Hog, LLC, 703 F.3d 1349,
1356 (Fed. Cir. 2012) (quoting Warner–Jenkinson, 520
U.S. at 40). “Courts should be cautious not to shortcut
this inquiry by identifying a ‘binary’ choice in which an
element is either present or ‘not present.’” Id. at 1356; see
also Brilliant Instruments, Inc. v. GuideTech, LLC, 707
F.3d 1342, 1347 (Fed. Cir. 2013).
     Here, the district court “shortcut” the inquiry by iden-
tifying a binary choice (continuous or intermittent) that is
not compelled by the ’371 patent and the record evidence.
The district court’s decision does not consider the func-
tioning of the EPOS Products as part of its determination
on infringement by the doctrine of equivalents. Addition-
ally, the decision does not consider Pegasus’s expert
declaration explaining why the EPOS Products’ signals
are equivalent to the claimed intermittent ultrasound
signal. The district court should have more thoroughly
considered whether a reasonable jury could conclude that
intermittent and continuous signals are equivalent,
rather than just “shortcutting” its analysis. Accordingly,
we vacate the district court’s grant of summary judgment
of noninfringement under the doctrine of equivalents so
that the district court may reconsider this issue on re-
mand.
                             V
    We vacate the district court’s constructions of “draw-
ing implement,” “given time interval,” “marking imple-
ment,” and “temporary attachment,” and the district
court’s grant of summary judgment of noninfringement of
the ’371 patent under the doctrine of equivalents. We also
reverse the district court’s grant of summary judgment of
noninfringement regarding the ’051, ’565, ’461, and ’742
patents and remand for proceedings consistent with this
opinion.
18    EPOS TECHNOLOGIES LTD.   v. PEGASUS TECHNOLOGIES LTD.



 VACATED-IN-PART, REVERSED-IN-PART, AND
               REMANDED
     No costs.
