  United States Court of Appeals
      for the Federal Circuit
                ______________________

 WORLD CLASS TECHNOLOGY CORPORATION,
          an Oregon corporation,
             Plaintiff-Appellee,

                           v.

              ORMCO CORPORATION,
              a Delaware corporation,
                 Defendant-Appellant.
                ______________________

                 2013-1679, 2014-1692
                ______________________

    Appeals from the United States District Court for the
District of Oregon in No. 3:13-cv-00401-AC, Magistrate
Judge John V. Acosta.
                 ______________________

               Decided: October 20, 2014
                ______________________

    BRIAN G. BODINE, Lane Powell PC, of Seattle, Wash-
ington, argued for plaintiff-appellee. With him on the
brief was PETER D. HAWKES, of Portland, Oregon. Of
counsel on the brief was WILLIAM O. GENY, Chernoff
Vilhauer LLP, of Portland, Oregon.

    PATRICK J. COYNE, Finnegan, Henderson, Farabow,
Garrett & Dunner, LLP, of Washington, DC, argued for
defendant-appellant.  Of counsel on the brief were
GREGORY F. AHRENS and PAUL J. LINDEN, Wood, Herron &
2     WORLD CLASS TECHNOLOGY CORP     v. ORMCO CORPORATION



Evans, L.L.P., of Cincinnati, Ohio; and CHRISTOPHER B.
MEAD, London & Mead, of Washington, DC.
                 ______________________

Before PROST, Chief Judge, TARANTO and HUGHES, Circuit
                        Judges.
TARANTO, Circuit Judge.
    Ormco Corporation owns U.S. Patent No. 8,393,896,
which claims a bracket for orthodontic braces that avoids
or reduces interference with the gums even when being
mounted on a molar tooth. Ormco accuses World Class
Technology Corporation of infringing the ’896 patent, and
World Class Technology denies infringement. The district
court construed two claim terms—“support surface” and
“ledge.” In view of the court’s constructions, the parties
stipulated to a judgment of non-infringement of the ’896
patent. We affirm, rejecting Ormco’s challenge to the
district court’s construction of “support surface,” which, by
the parties’ stipulation, suffices for non-infringement.
                       BACKGROUND
     The ’896 patent, entitled “Self-Ligating Orthodontic
Bracket,” describes a bracket that attaches to a tooth for
orthodontic braces. ’896 patent, Title and Abstract. The
bracket includes a slot to hold the archwire that connects
(and exerts the desired corrective force on) the teeth, with
a slide that moves across the slot opening to hold the wire
in place. Id., col. 1, line 19, through col. 2, line 44. The
specification notes that self-ligating brackets were al-
ready known in the art. Id., col. 1, lines 29–32. It states,
however, that the prior-art brackets did not work well for
molars, explaining that when the slide opened to release
the wire it would bump into the gums, causing discomfort.
Id., col. 1, line 59, through col. 2, line 5.
    The specification discloses a bracket that it says
solves the problem. It describes a bracket structured so
4     WORLD CLASS TECHNOLOGY CORP    v. ORMCO CORPORATION



    gled with respect to the base surface, and the ledge
    opposing the support surface across the archwire
    slot and including a surface that is generally par-
    allel to the base surface; and a movable member
    coupled with the bracket body and movable be-
    tween an opened position in which the archwire is
    insertable into the archwire slot and a closed posi-
    tion in which the movable member retains the
    archwire in the archwire slot, wherein the mova-
    ble member comprises a first portion and a second
    portion extending at an acute angle from the first
    portion, the first portion engaging the acutely an-
    gled support surface of the bracket body when the
    movable member is in the closed position, the sec-
    ond portion being generally parallel to the base
    surface and extending across the archwire slot
    from the first slot surface to the second slot sur-
    face when the movable member is in the closed
    position.
’896 patent, col. 10, lines 28–53 (emphases added).
    World Class Technology brought the present case by
seeking a declaratory judgment of non-infringement of
five other Ormco patents, but the ’896 patent became the
focus of the dispute when Ormco counterclaimed, and
sought a preliminary injunction, based on the allegation
that World Class Technology was infringing the ’896
patent. The heart of the parties’ dispute is what con-
straints claim 1 places on the “support surface” during
movement of the movable member (slide). As a comple-
ment to that issue, the parties also dispute what role is
played by the “ledge” surface that lies on the other side of
the wire-holding slot from the support surface.
     Because claim 1 explicitly limits the support surface
to “engaging” one portion of the slide when it is in the
closed position, Ormco has argued that the claim does not
require the support surface to play any role during slide
WORLD CLASS TECHNOLOGY CORP    v. ORMCO CORPORATION       5



movement until the slide crosses the slot to move into the
closed position. As long as it does that, and is situated at
an acute angle to the base of the slot, no further support
of the slide during sliding is required. World Class Tech-
nology, in contrast, has argued that “support surface,”
properly construed, requires the surface to play a slide-
supporting role as the slide moves along its (angled) path
from one side of the slot, across the slot, and into the
closed position at the ledge. What is critical for the accu-
sation of infringement, Ormco’s position is that the claim
language is broad enough to cover two arrangements. In
one, shown in Figures 1 and 3, the slide is inserted from
the bottom, moves first along the support surface, and
reaches the ledge for closing. In the other, nowhere
shown or described in the patent’s drawings or written
description, the slide would be inserted from a top open-
ing, move first along the ledge, and come to rest at the
support surface after crossing the slot.
    The district court rejected Ormco’s argument. In
denying the requested preliminary injunction, and then
again upon full consideration of the claim-construction
dispute, the court held that the support surface “at least
partially supports and guides the movable member during
movement between the open position and the closed
position.” World Class Tech. Corp. v. Ormco Corp., 964 F.
Supp. 2d 1273, 1280, 1285 (D. Or. 2013); World Class
Tech. Corp. v. Ormco Corp., No. 13-cv-00401, 2013 WL
5723306, at *4, *10 (D. Or. Oct. 21, 2013). In the latter
ruling, the district court adopted a complementary con-
struction of “ledge” as contacting the slide only when the
slide is in the closed position. World Class Tech., 2013
WL 5723306, at *10.
    Ormco and World Class Technology eventually stipu-
lated to non-infringement of the ’896 patent under the
“support surface” construction. The parties separately
stipulated to non-infringement of the other five patents in
the case, which are no longer at issue. The district court
6     WORLD CLASS TECHNOLOGY CORP     v. ORMCO CORPORATION



entered a final judgment, and Ormco appeals. We have
jurisdiction under 28 U.S.C. § 1295(a)(1).
                        DISCUSSION
    Claim construction is a matter of law that this court
reviews de novo. Cybor Corp. v. FAS Techs., Inc., 138
F.3d 1448, 1451 (Fed. Cir. 1998) (en banc). We generally
give words of a claim their ordinary meaning in the
context of the claim and the whole patent document; the
specification particularly, but also the prosecution history,
informs the determination of claim meaning in context,
including by resolving ambiguities; and even if the mean-
ing is plain on the face of the claim language, the patentee
can, by acting with sufficient clarity, disclaim such a plain
meaning or prescribe a special definition. See, e.g., Phil-
lips v. AWH Corp., 415 F.3d 1303, 1312–17 (Fed. Cir.
2005) (en banc); Thorner v. Sony Computer Entm’t Am.
LLC, 669 F.3d 1362, 1365 (Fed. Cir. 2012). Following
that approach, we reject Ormco’s challenge to the district
court’s construction of “support surface,” which Ormco
stipulated requires non-infringement, without separate
consideration of “ledge.”
    The claim language does not by itself convey a clear,
unambiguous meaning in the respect at issue. To begin
with, while “support surface” requires a surface that
provides support, and the slide is undisputedly what must
be supported, the language itself does not resolve when
the slide must be supported. An “engaging” must take
place in the fully closed position, according to the claim.
But the phrase “support surface” standing alone could
mean that support must be provided generally during
movement of the slide.
    Moreover, the claim requires two surfaces on either
side of the archwire slot and gives the surfaces two differ-
ent names: the “support surface” and the “ledge” surface.
’896 patent, col. 10, lines 27–53. That difference suggests
that their roles are different—which points away from
WORLD CLASS TECHNOLOGY CORP    v. ORMCO CORPORATION        7



Ormco’s suggestion that they are interchangeable regard-
ing the timing of contact with the slide (in Ormco’s view,
either one can be contacted at the end of the sliding
process, either one at the start). Indeed, the claim not
only gives them separate names, but requires the two
surfaces to line up differently relative to the base surface
of the slot: the support surface must be at an acute angle
relative to the base surface; the ledge surface must be
parallel to the base surface. And the claim requires a
specific interaction (“engaging”) between one surface (the
support surface) and a portion of the angled slide when in
the closed position, with no analogous requirement for the
other surface.
    Rather than providing an unambiguous, clear mean-
ing, therefore, the claim language leaves uncertainty
about whether, contrary to Ormco’s view, the slide must
move along the support surface (and not the ledge sur-
face) as it enters the bracket and moves toward the slot.
In such circumstances, we turn to the specification to
resolve the uncertainty. See Phillips, 415 F.3d at 1315–16
(quoting Bates v. Coe, 98 U.S. 31, 38 (1878) (“in case of
doubt or ambiguity it is proper in all cases to refer back to
the descriptive portions of the specification to aid in
solving the doubt or in ascertaining the true intent and
meaning of the language employed in the claims”); White
v. Dunbar, 119 U.S. 47, 51 (1886) (specification is appro-
priately resorted to “for the purpose of better understand-
ing the meaning of the claim”); Schriber–Schroth Co. v.
Cleveland Trust Co., 311 U.S. 211, 217 (1940) (“The
claims of a patent are always to be read or interpreted in
light of its specifications.”); United States v. Adams, 383
U.S. 39, 49 (1966) (“[I]t is fundamental that claims are to
be construed in the light of the specifications and both are
to be read with a view to ascertaining the invention.”)).
Where, as here, the claim language itself leaves interpre-
tive questions unanswered, “[t]he construction that stays
true to the claim language and most naturally aligns with
8     WORLD CLASS TECHNOLOGY CORP       v. ORMCO CORPORATION



the patent’s description of the invention will be, in the
end, the correct construction.” Renishaw PLC v. Marposs
Societa’ per Azioni, 158 F.3d 1243, 1250 (Fed. Cir. 1998),
adopted by Phillips, 415 F.3d at 1316.
    Critically, the specification in this case identifies gum
avoidance as the sole purpose of the acute angle the
support surface must make with the slot base. See, e.g.,
’896 patent, Abstract; id., col. 1, line 66, through col. 2,
line 5; id., col. 2, lines 40–44. Under Ormco’s construc-
tion, however, the acute angle would not serve the sole
stated purpose in the arrangement that Ormco’s construc-
tion is aimed at covering—in which the slide is inserted
from the top, first moves along the ledge, and arrives at
the support surface for closing after crossing the slot. In
that embodiment, there is no problem of gum contact and
no need for the acute angle. Such a construction is un-
moored from, rather than aligned with, the description of
the invention.
     Ormco has not identified anything in the written de-
scription or drawings that discloses an arrangement of
the sort it seeks to cover, in which the slide does not
contact the support surface until it approaches the closed
position. And it is not just the sole statement of purpose
of the acute angle, but other language of the specification,
that shows Ormco’s view to be out of keeping with the
description of the invention. Notably, the patent uses the
phrase “translation plane” in identifying the key required
acute angle (which is formed with the “base plane”). E.g.,
’896 patent, col. 2, lines 31–32; id., col. 2, lines 40–44; id.,
col. 6, lines 7–23; id., col. 7, lines 8–12 and lines 18–21;
see also id., col. 10, lines 3–7; id. at fig. 3. The terminolo-
gy of “translation” refers to movement of the slide—which
is “translat[ed]” along the plane. Id., col. 6, lines 1–4
(“translation plane 60 along which the ligating slide 14
moves”). And the patent makes clear that the “planar
support surface 46 including grooves 48, 50 and guides 52,
54 collectively define a slide engagement track,” which is
WORLD CLASS TECHNOLOGY CORP    v. ORMCO CORPORATION       9



what “generally defines a translation plane 60 along
which the ligating slide 14 moves.” Id., col. 5, line 61,
through col. 6, line 4 (emphasis added). By thus tying the
“translation” plane to the support surface, the patent
strongly implies that it is along the support surface, not
the ledge surface, that the slide generally moves from
open to closed position.
     The specification also sharpens the distinction be-
tween the support surface and the ledge surface that is
suggested by the use of two different terms for the two
surfaces. Whereas the support surface is linked with slide
movement, the ledge is not. It is mentioned in a single
paragraph. That paragraph explains that when the slide
is closed, one end of the slide “abuts the labial surface of
[the] ledge.” Id., col. 7, lines 29–32 (figure reference
numbers removed). The rest of the paragraph then de-
scribes a portion of the bracket connected to the ledge
that covers the end of the slide, protecting the slide
against food and acting as a stop for the slide’s movement
(depicted as item 34 in Figure 3). Id., col. 7, lines 32–38.
Such statements are inconsistent with Ormco’s construc-
tions of “ledge” and “support surface,” which would allow
the slide to move along either surface interchangeably.
    For those reasons, we conclude that the specification
makes clear that the district court correctly resolved the
uncertainties in the claim language, adopting a construc-
tion that aligns with the description of the invention.
    Given that conclusion, we also reject Ormco’s argu-
ment that the difference between claim 6 and claim 1
demands a broad construction of claim 1. Claim 6, which
depends on claim 1, adds the limitations that “the support
surface intersects one of the opposing first and second slot
surfaces to define an edge of the archwire slot and the
support surface defines a translation plane that intersects
the other of the opposing first and second slot surfaces.”
’896 patent, col. 11, lines 1–5. Since the phrase “the
10    WORLD CLASS TECHNOLOGY CORP     v. ORMCO CORPORATION



support surface defines a translation plane” appears
explicitly in claim 6, Ormco argues, we should not read
claim 1 as itself limiting the support surface to supporting
and guiding the slide during “translation.” We conclude,
however, that this difference is not sufficient to support
Ormco’s broad view of claim 1.
    The doctrine of claim differentiation creates a pre-
sumption that distinct claims, particularly an independ-
ent claim and its dependent claim, have different scopes.
See Kraft Foods, Inc. v. Int’l Trading Co., 203 F.3d 1362,
1368 (Fed. Cir. 2000). But our construction of “support
surface” does not give claim 1 the same scope as claim 6.
At a minimum, claim 6 requires that the support surface
form a corner (edge) with one side of the slot. That re-
quirement is not implicit in claim 1 under our construc-
tion of “support surface.” To provide support for the slide
throughout its movement, the support surface need not
come directly up to the slot (or, therefore, form a corner
with a slot side), but could stop short of the slot.
    With claim 6 having independent significance, we see
no basis for reading into its use of “translation” an impli-
cation that, but for the limitations claim 6 adds to claim 1,
the slide need not move along the support surface. The
focus of claim 6 seems more on a geometric characteriza-
tion than on any question about support during move-
ment; and the claim is readily understood to reinforce the
connection between the support surface and the slide’s
movement by tying the “translation plane” to the “support
surface.” In any event, as we have concluded, the specifi-
cation firmly establishes the requirement of slide support
that Ormco disputes. That conclusion precludes drawing
the inference from claim 6 that Ormco urges. Indeed,
recognizing that claim drafting often involves finding
different expressions to define the same invention, Kraft,
203 F.3d at 1368, we have held that even the presumption
of different claim scope is “ ‘ overcome by a contrary con-
struction dictated by the written description,’ ” Retracta-
WORLD CLASS TECHNOLOGY CORP   v. ORMCO CORPORATION      11



ble Techs., Inc. v. Becton, Dickinson & Co., 653 F.3d 1296,
1305 (Fed. Cir. 2011) (quoting Seachange Int’l, Inc. v. C-
COR, Inc., 413 F.3d 1361, 1369 (Fed. Cir. 2005)); see also
Kraft, 203 F.3d at 1368. A fortiori, we will not draw
Ormco’s inference from claim 6 here, where the inference
is not even needed to maintain different claim scope.
    We note, finally, that we do not find support for
Ormco’s position in the prosecution history, on which
neither side places substantial weight. In particular, our
conclusion is not changed by the Examiner-Initiated
Interview Summary, U.S. Patent App. No. 13/052,759
(U.S.P.T.O. July 30, 2012). That document reports an
interview in which (a) the examiner told the applicant
that “the claims would most likely be allowable over the
prior art if limitations were included in the claims that
stated that the ligating member was moved linearly and
that the first portion of the ligating member remained in
contact with the support surface during the entire move-
ment of the ligating member” and (b) the applicant re-
sponded that he “did not wish to amend the claims in the
manner proposed.” The document is not clear enough, as
to either the applicant’s or the examiner’s views about
claim scope in the absence of the proposed language, to
support a different construction of “support surface” from
the one we find compelled by the specification.
                       CONCLUSION
    For the foregoing reasons, we affirm the district
court’s decision.
                      AFFIRMED
