         NOTE: This disposition is nonprecedential

  United States Court of Appeals
      for the Federal Circuit
               __________________________

           ALTAIR ENGINEERING, INC.,
                Plaintiff-Appellant,
                            v.
                LEDDYNAMICS, INC.,
                  Defendant-Appellee.
               __________________________

                       2010-1118
               __________________________

   Appeal from the United States District Court for the
Eastern District of Michigan in case no. 07-CV-13150,
Judge George Caram Steeh
             ___________________________

                DECIDED: March 9, 2011
              ___________________________

   THOMAS N. YOUNG, Young & Basile, P.C., Troy, Michi-
gan, argued for plaintiff-appellant. With him on the brief
was CHRISTOPHER G. DARROW.

   R. BRADFORD FAWLEY, Downs, Rachlin Martin, PLLC,
Brattleboro, Vermont, argued for defendant-appellee.
With him on the brief was JAMIE T. GALLAGHER.
              __________________________
ALTAIR ENGINEERING   v. LEDDYNAMICS                        2


   Before RADER, Chief Judge, DYK, and PROST, Circuit
                        Judges.
DYK, Circuit Judge.
    Plaintiff Altair Engineering, Inc. (“Altair”) appeals the
district court’s judgment of non-infringement in favor of
defendant LEDdynamics, Inc. (“LEDdynamics”). Altair
challenges the district court’s claim construction and the
court’s conclusion that Altair was judicially estopped from
changing its position about the nature of the accused
product. We affirm the district court’s claim construction
but reverse its determination as to judicial estoppel. We
accordingly reverse the summary judgment of non-
infringement.
                       BACKGROUND
     Altair owns United States Patent No. 7,049,761 (“the
’761 patent”), which discloses a light tube that uses light
emitting diodes (“LEDs”) to serve as a replacement for the
typical fluorescent tube lights commonly used in schools
and offices. On July 27, 2007, Altair sued LEDdynamics
in the United States District Court for the Eastern Dis-
trict of Michigan, ultimately alleging that an LED-based
light tube produced by LEDdynamics infringed independ-
ent claim 3 and dependent claims 4, 16 and 17 of the ’761
patent.
    The district court held a Markman hearing on July
31, 2008, during which the only disputed term was
“closely-spaced” in claim 3. Claim 3 provides:
    In a replacement light tube for a fluorescent light
    fixture having a light tube socket and a power
    supply circuit, the improvement comprising:
    a plurality of closely-spaced light emitting diodes
    disposed inside a bulb portion of the light tube
3                       ALTAIR ENGINEERING   v. LEDDYNAMICS


    and in electrical communication with a pair of end
    caps coupled to opposed ends of the bulb portion
    and engageable with the light tube socket, the
    plurality of light emitting diodes operable to illu-
    minate in response to electrical current delivered
    by the fluorescent light [fixture]; and wherein
    each of the pair of end caps is an electrical bi-pin
    connector.
’761 Patent, col. 6 ll. 14–26 (emphasis added).
    At the Markman hearing, LEDdynamics argued that
the proper construction for “closely-spaced” was: “[N]ot
spaced-apart, such that adjacent LEDs are sufficiently
close that another LED cannot fit in the space therebe-
tween.” J.A. 114. Altair, conversely, suggested that the
correct construction was: “[M]ultiple LEDs arranged
inside of a bulb portion where the number and spacing of
the LEDs is such that, when lighted, the LEDs produce an
illumination level and effect which adequately performs
as a fluorescent light tube substitute.” J.A. 103. The
district court adopted LEDdynamics construction, finding
that it was supported by the figures in the specification
and prosecution history and would prevent the claim from
being invalidated as indefinite.
     After the Markman proceedings, LEDdynamics moved
for summary judgment of non-infringement. Throughout
its Markman briefing, Altair had characterized the ac-
cused product as containing 36 LEDs. Under the district
court’s claim construction, these 36 LEDs were “spaced-
apart, such that adjacent LEDs are sufficiently close that
another LED cannot fit in the space therebetween.” Thus,
treating the accused product as consisting of 36 LEDs, it
did not infringe. In opposing the motion, Altair for the
first time relied on its assertion that the 36 LEDs in the
accused product were “actually packages of six LEDs
ALTAIR ENGINEERING   v. LEDDYNAMICS                      4


arranged very close to one another” and that the product,
therefore, had 216 LEDs which were “closely-spaced.” 1
J.A. 128. Altair also moved to amend its infringement
contentions to add new claims of the ’761 patent that it
believed were infringed.
    The district court found Altair was judicially estopped
from arguing that the accused product contained 216
closely-spaced LEDs because (1) its “new argument . . . is
clearly at odds with its consistent position during the
Markman proceedings,” (2) “this Court adopted Altair’s
definition of LEDs in the accused device,” and (3)
“[c]hanging the definition of LED now . . . would prejudice
LED dynamics.” Altair Eng’g, Inc. v. LEDdynamics, Inc.,
No. 07-CV-13150, slip op. at 5–7 (E.D. Mich. March 24,
2009). The district court also denied Altair’s motion to
add additional claims, finding that Altair lacked good
cause to amend infringement contentions made in re-
sponse to the court’s scheduling order (an issue not raised
on appeal). To allow for a final judgment to be entered so
the case could be appealed, LEDdynamics withdrew its
invalidity counterclaims. Altair timely appealed the
summary judgment of non-infringement. We have juris-
diction over Altair’s appeal pursuant to 28 U.S.C. §
1295(a)(1).
                        DISCUSSION
    Altair challenges the district court’s claim construc-
tion and its holding as to judicial estoppel. Claim con-
struction is an issue of law that we review de novo. Key
Pharm. v. Hercon Labs. Corp., 161 F.3d 709, 713 (Fed.
Cir. 1998). Because judicial estoppel is not an issue

   1   Altair did tell the court during the Markman
hearing that it had “discovered that the [LEDs used in the
accused product] are actually six small LED chips wired
together.” J.A. 744.
5                        ALTAIR ENGINEERING   v. LEDDYNAMICS


unique to patent law, we look to the law of the applicable
regional circuit, which here is the Sixth Circuit. See
Biomedical Patent Mgmt. Corp. v. California Dep’t of
Health Servs., 505 F.3d 1328, 1341 (Fed. Cir. 2007). The
Sixth Circuit reviews a district court’s use of judicial
estoppel de novo. Browning v. Levy, 283 F.3d 761, 775
(6th Cir. 2002).
                               I
    With respect to claim construction, the parties agree
that the text of the specification does not define or even
use the phrase “closely-spaced” and that the phrase has
no accepted meaning in the relevant art. Altair asserts
that the district court erred by relying on the figures in
the specification to arrive at its definition of “closely-
spaced,” and that its proposed claim construction is
consistent with the purpose of the invention, which was
“to provide a light tube . . . which overcome[s] the short-
comings of conventional fluorescent lighting systems” (i.e.,
a substitute for conventional fluorescent tube lighting).
See ’761 Patent, col. 1, ll. 30–32. However, as the district
court noted, the term “closely-spaced” appears to refer to
spatial separation, not to the functionality of the inven-
tion. While we agree that the figures in the specification
in and of themselves do not define “closely-spaced,” the
prosecution history makes clear that the district court’s
construction is correct.
    Claim 3 was originally drafted without the “closely-
spaced” limitation, and Altair inserted the limitation
during prosecution to distinguish its invention from prior
art U.S. Patent No. 4,748,545 (the “Schmitt patent”). The
Schmitt patent discloses a cabinet display light, which is
long and tubular and contains three incandescent or
halogen lamps that are “spaced-apart,” see, e.g., Schmitt
patent, col. 5, l. 29, in order to create “point light sources”
ALTAIR ENGINEERING   v. LEDDYNAMICS                       6


to concentrate on the items on display, id. at col. 1, l.25.
The light sources in the Schmitt patent allow an interven-
ing light source of the same type to be placed in between
each light.
    When adding the closely-spaced limitation to its
claim, Altair argued to the examiner that “Schmitt does
not teach or suggest a plurality of closely-spaced [LEDs]
extending between the opposite ends of the bulb portion,
which is shown by example in Applicants’ Figures 1 and 2.
A critical feature of Schmitt is the existence of spaced-
apart light sources . . . .” J.A. 296 (emphases added).
Here, not only did Altair admit that the limitation was
added to distinguish the claim from “spaced apart” light
sources, but it also relied explicitly (and heavily) on the
figures to explain what it meant by “closely-spaced.” Both
figures 1 and 2 show LEDs arranged in banks of three
such that each LED nearly touches another LED. In
other words, it appears that another LED could not be
placed in the space between LEDs. Figure 2 (in which the
LEDs are labeled 22) is set forth below:
7                      ALTAIR ENGINEERING   v. LEDDYNAMICS




’761 Patent fig.2. Although patentees are, of course, not
limited to a single preferred embodiment as disclosed in
the figures, here the patentee specifically referenced the
figures displaying its preferred embodiment when ex-
plaining what it meant by “closely-spaced.” Altair distin-
guished the Schmitt patent by adding “closely-spaced”
and in describing the claim term made explicit reference
to figures that show LEDs practically touching across the
entire tube. The fact that the Schmitt patent could also
have been distinguished on some other ground (i.e., that it
does not use LEDs) is irrelevant. See, e.g., Andersen Corp
v. Fiber Composites, LLC, 474 F.3d 1361, 1374 (Fed. Cir.
2007) (“[A]n applicant's argument that a prior art refer-
ence is distinguishable on a particular ground can serve
ALTAIR ENGINEERING   v. LEDDYNAMICS                        8


as a disclaimer of claim scope even if the applicant distin-
guishes the reference on other grounds as well.”).
    Despite Altair’s claims to the contrary, other aspects
of the prosecution history also support the district court’s
construction. Altair argues that the examiner rejected a
proposed claim of the ’761 patent that included the term
“closely-spaced” based on U.S. Patent No. 6,394,623 (the
“Tsui patent”) even though the light sources in the Tsui
patent apparently were spaced far enough apart that
another light could be placed in between. Therefore,
according to Altair, the examiner must have interpreted
“closely-spaced” as not requiring that other lights could
not be placed in between.
    While the examiner’s interpretation can be pertinent,
the applicant’s own interpretation has far more signifi-
cance. See, e.g., Springs Window Fashions LP v. Novo
Indus., LP, 323 F.3d 989, 995 (Fed. Cir. 2003) (focusing on
applicant’s statements distinguishing prior art during
prosecution despite the fact that examiner may not have
relied on those statements and, instead, had a different
reason for allowance); Spectrum Int'l, Inc. v. Sterilite
Corp., 164 F.3d 1372, 1378–79 (Fed. Cir. 1998) (noting
that “explicit arguments made [by the applicant] during
prosecution” are significant and that “by distinguishing
the claimed invention over the prior art, an applicant is
indicating what the claims do not cover”). Here, Altair
itself distinguished the Tsui patent by stating to the
examiner that “Tsui fails to teach or suggest a plurality of
closely-spaced [LEDs] disposed inside the bulb portion”
and instead “teaches a plurality of spaced-apart lights.”
J.A. 341. Altair pointed out to the examiner the fact that
the Tsui patent explicitly discloses “spaced-apart lights.”
E.g., Tsui patent, col. 6, l.22. Therefore, Altair clearly
urged that, in contrast to its patent, the lights in the Tsui
patent (which allowed a light to be placed in the interven-
9                      ALTAIR ENGINEERING   v. LEDDYNAMICS


ing space) were not closely-spaced. Altair’s interpretation
during prosecution is highly significant.
    Altair also argues that the examiner rejected a pro-
posed claim that included the “closely-spaced” limitation
as anticipated by U.S. Patent No. 6,325,651 (the “Nishi-
hara patent”) and that rejection must have assumed that
the lights in Nishihara are “closely-spaced.” The figures
from the Nishihara patent show that the incandescent
lights disclosed in that patent are much larger than LEDs
and, despite being several inches apart, are still close
enough to each other that another incandescent light of
the same size could not be placed between the lights. See
Nishihara patent, fig.7. Therefore, the examiner’s rejec-
tion based on the Nishihara patent actually supports the
district court’s claim construction of “sufficiently close
that another [of the same type of light] cannot fit in the
space therebetween.”
    Therefore, we hold that the figures and prosecution
history support the district court’s claim construction.
The proper construction was “not spaced-apart, such that
adjacent LEDs are sufficiently close that another LED
cannot fit in the space therebetween.”
                            II
    With respect to judicial estoppel, Altair argues that
the issue of the nature of the accused product was never
contested, and it never prevailed on the definition of LED.
Under these circumstances, it asserts that it cannot be
estopped from changing its characterization of the ac-
cused product. We agree. In New Hampshire v. Maine,
532 U.S. 742, 750–51 (2001), the Supreme Court de-
scribed three factors used to determine whether judicial
estoppel should apply:
ALTAIR ENGINEERING   v. LEDDYNAMICS                        10


   First, a party's later position must be clearly in-
   consistent with its earlier position. Second, courts
   regularly inquire whether the party has succeeded
   in persuading a court to accept that party's earlier
   position, so that judicial acceptance of an inconsis-
   tent position in a later proceeding would create
   the perception that either the first or the second
   court was misled. . . . A third consideration is
   whether the party seeking to assert an inconsis-
   tent position would derive an unfair advantage or
   impose an unfair detriment on the opposing party
   if not estopped.
Id. (internal citations and quotations omitted). The Court
explained that judicial estoppel “prevents a party from
prevailing in one phase of a case on an argument and
then relying on a contradictory argument to prevail in
another phase.” Id. at 749 (quoting Pegram v. Herdrich,
530 U.S. 211, 227 n.8 (2000)). Here, Altair did not prevail
in any phase of the case. In fact, Altair lost its argument
on claim construction. The district court rejected Altair’s
proposed construction and accepted the one proposed by
LEDdynamics. Whether the accused product contained
36 or 216 LEDs was never even a contested issue. Indeed,
at oral argument, LEDdynamics conceded that Altair “did
not prevail on anything substantive.” Oral Arg. at 16:04–
16:07, available at http://www.cafc.uscourts.gov/oral-
argument-recordings/2010-1118/all. Therefore, application
of judicial estoppel was improper.
    Altair’s new evidence regarding the grouping of LEDs
in the accused product raises a substantial issue of mate-
rial fact. With LEDdynamics’ motion for summary judg-
ment, it submitted an affidavit from William McGrath
stating that the accused product contained “36 LEDs”
spaced “approximately 1.25 inches apart.” J.A. 123.
Altair submitted an affidavit along with its reply from
11                      ALTAIR ENGINEERING   v. LEDDYNAMICS


John Ivey, asserting that, after magnifying the image of
the accused device, he found each of the 36 devices “actu-
ally consists of a grouping of six LEDs arranged [such
that] . . . [t]he six LEDs in each grouping are too close to
one another to allow an LED to be fit between them.” J.A.
133. Although Ivey’s affidavit differs from his prior
declaration that the LEDs on the accused product “were a
little over one inch apart,” the change in position does not
preclude finding a material issue of fact. See Checkpoint
Sys., Inc. v. All Tag Sec. S.A., 412 F.3d 1331, 1338 (Fed.
Cir. 2005) (finding issue of material fact where content of
witness declarations differed from prior declarations
given to Patent and Trademark Office). Therefore, the
district court erred in granting LEDdynamics’ motion for
summary judgment of non-infringement. While Altair
may not ultimately prevail in its infringement suit based
on its new characterization of the accused product, it is at
least entitled to try.
                             III
    We thus affirm the district court’s claim construction
of the term “closely-spaced” but reverse the district court’s
summary judgment of non-infringement. 2


     2    LEDdynamics argues on appeal that claim 3 of
the ’761 patent should be invalidated for indefiniteness or
lack of written description. Its invalidity counterclaims
were dismissed by the district court without prejudice.
LEDdynamics did not file a cross-appeal. Even if the
dismissal without prejudice were not a bar to its invalid-
ity claims on appeal, LEDdynamics cannot seek invalidity
of the ’761 patent in the absence of a cross-appeal. See
Typeright Keyboard Corp. v. Microsoft Corp., 374 F.3d
1151, 1157 n.4 (Fed. Cir. 2004) (“[W]here the appellee
urges invalidity as a new ground on which to support a
judgment of non-infringement . . . a cross-appeal is neces-
sary . . . .”).
ALTAIR ENGINEERING   v. LEDDYNAMICS    12


 AFFIRMED-IN-PART, REVERSED-IN-PART, and
               REMANDED
                           Costs
   No costs.
