  United States Court of Appeals
      for the Federal Circuit
                ______________________

    SPORT DIMENSION, INC., A CALIFORNIA
              CORPORATION,
              Plaintiff-Appellee

                           v.

 THE COLEMAN COMPANY, INC., A DELAWARE
            CORPORATION,
           Defendant-Appellant
          ______________________

                      2015-1553
                ______________________

   Appeal from the United States District Court for the
Central District of California in No. 2:14-cv-00438-BRO-
MRW, Judge Beverly Reid O’Connell.
                 ______________________

                Decided: April 19, 2016
                ______________________

   YURI MIKULKA, Manatt, Phelps & Phillips, LLP, Costa
Mesa, CA, argued for plaintiff-appellee. Also represented
by MICHAEL I. ROTHWELL, Los Angeles, CA.

   MICHAEL R. ANNIS, Husch Blackwell LLP, St. Louis,
MO, argued for defendant-appellant. Also represented by
JOANN TRACY SANDIFER.
                ______________________

     Before MOORE, HUGHES, and STOLL, Circuit Judges.
2       SPORT DIMENSION, INC.   v. THE COLEMAN COMPANY, INC.



STOLL, Circuit Judge.
    Coleman Company, Inc. appeals from a stipulated
judgment of noninfringement entered by the United
States District Court for the Central District of California.
Coleman challenges the district court’s claim construction
on which the stipulated judgment was based and its
exclusion of Coleman’s expert. For the reasons stated
below, we vacate the judgment, affirm the court’s exclu-
sion of Coleman’s expert, and remand for proceedings
consistent with this opinion.
                        BACKGROUND
    Coleman is an outdoor sporting equipment company
that sells an array of products, including personal flota-
tion devices. Coleman owns United States Design Patent
No. D623,714 (“D’714 patent”). It claims “[t]he ornamen-
tal design for a personal flotation device,” as shown in
Figures 1 and 2 below.




D’714 patent Figs. 1, 2. The D’714 patent generally
discloses a personal flotation device with two arm bands
connected to a torso piece. The torso piece is flat on its
back and tapers toward a connecting strap on its sides.
    Sport Dimension is a sports equipment and apparel
company that sells water-sports-related equipment,
including its Body Glove® line of personal flotation devic-
es. Sport Dimension’s Body Glove® Model 325 is the
accused device and is shown below.
SPORT DIMENSION, INC.   v. THE COLEMAN COMPANY, INC.      3




Supplemental Appendix 1474–75.          Sport Dimension’s
accused personal flotation devices, like Coleman’s design,
have two armbands connected to a torso piece. But,
unlike Coleman’s design, the torso section in the Body
Glove® device extends upwards to form a vest that goes
over a person’s shoulders.
    Sport Dimension filed a declaratory judgment action
in the Central District of California requesting judgment
that it did not infringe the D’714 patent and that the
patent is invalid. The district court issued two rulings
that we now review.
    First, the court excluded the testimony of Coleman’s
expert, Peter Bressler. Sport Dimension had argued that
Mr. Bressler was not qualified to testify on the functional-
ity of the D’714 patent’s design, and the court agreed. It
4       SPORT DIMENSION, INC.   v. THE COLEMAN COMPANY, INC.



explained that, while Mr. Bressler “appears to possess
substantial experience in the field of industrial design,”
Coleman “does not dispute—and Mr. Bressler’s deposition
testimony makes it quite clear—that Mr. Bressler has no
substantive experience in the narrower field of personal
flotation device design.” Joint Appendix (“J.A.”) 12 (em-
phasis in original). Because the court viewed Mr. Bress-
ler’s experience as insufficient to opine on the contested
issues as an expert, it excluded his testimony.
    Second, the district court adopted Sport Dimension’s
proposed claim construction, as follows:
    The ornamental design for a personal flotation
    device, as shown and described in Figures 1–8, ex-
    cept the left and right armband, and the side torso
    tapering, which are functional and not ornamen-
    tal.
J.A. 3. Notably, this construction eliminates several
features of Coleman’s claimed design, specifically the
armbands and the side torso tapering. The court “found
that the armbands, the armband attachments, the shape
of the armbands, the tapering of the armbands, and the
tapering of the side torso were all elements that serve a
functional rather than ornamental purpose in the D’714
patent.” J.A. 3. In light of the court’s claim construction
order, Coleman moved for entry of judgment of nonin-
fringement in favor of Sport Dimension so that it could
appeal the claim construction. The court entered judg-
ment, and Coleman timely appealed. We have jurisdic-
tion under 28 U.S.C. § 1295(a)(1).
                       DISCUSSION
                            A.
     We review the district court’s ultimate claim construc-
tion of a design patent de novo. Ethicon Endo-Surgery,
Inc. v. Covidien, Inc., 796 F.3d 1312, 1333 (Fed. Cir. 2015)
(citing Teva Pharm. USA, Inc. v. Sandoz, Inc., 135 S. Ct.
SPORT DIMENSION, INC.   v. THE COLEMAN COMPANY, INC.       5



831, 841 (2015)). We review any factual findings underly-
ing the construction for clear error. Id.
     Words cannot easily describe ornamental designs. See
Dobson v. Dornan, 118 U.S. 10, 14 (1886) (explaining that
a claim “is better represented by the photographic illus-
tration than it could be by any description, and a descrip-
tion would probably not be intelligible without the
illustration”). A design patent’s claim is thus often better
represented by illustrations than a written claim con-
struction. Egyptian Goddess, Inc. v. Swisa, Inc., 543 F.3d
665, 679 (Fed. Cir. 2008) (en banc). Also, detailed verbal
claim constructions increase “the risk of placing undue
emphasis on particular features of the design and the risk
that a finder of fact will focus on each individual described
feature in the verbal description rather than on the
design as a whole.” Id. at 680.
    Even so, a district court may use claim construction to
help guide the fact finder through issues that bear on
claim scope. Id. We have often blessed claim construc-
tions, for example, where the court helped the fact finder
“distinguish[] between those features of the claimed
design that are ornamental and those that are purely
functional.” Id. (citing OddzOn Prods., Inc. v. Just Toys,
Inc., 122 F.3d 1396, 1405 (Fed. Cir. 1997)). Of course, a
design patent cannot claim a purely functional design—a
design patent is invalid if its overall appearance is “dic-
tated by” its function. Id. at 668. But as long as the
design is not primarily functional, “the design claim is not
invalid, even if certain elements have functional purpos-
es.” Ethicon Endo-Surgery, 796 F.3d at 1333 (citing
Richardson v. Stanley Works, Inc., 597 F.3d 1288, 1293–
94 (Fed. Cir. 2010)). That is because a design patent’s
claim protects an article of manufacture, which “neces-
sarily serves a utilitarian purpose.” L.A. Gear, Inc. v.
Thom McAn Shoe Co., 988 F.2d 1117, 1123 (Fed. Cir.
1993). So a design may contain both functional and
ornamental elements, even though the scope of a design
6       SPORT DIMENSION, INC.   v. THE COLEMAN COMPANY, INC.



patent claim “must be limited to the ornamental aspects
of the design.” Ethicon Endo-Surgery, 796 F.3d at 1333.
“Where a design contains both functional and non-
functional elements, the scope of the claim must be con-
strued in order to identify the non-functional aspects of
the design as shown in the patent.” OddzOn Prods., 122
F.3d at 1405.
     In OddzOn, for example, we considered a design pa-
tent on a rocket-shaped football and endorsed the district
court’s construction that distinguished between functional
and ornamental aspects of the design. The design patent
disclosed a football with a large tail fin that added stabil-
ity for the ball in flight. Id. at 1406. The fins also pro-
duced an “overall ‘rocket-like’ appearance of the design.”
Id. at 1405. We agreed with the district court’s finding
that the fins were functional. Nevertheless, we approved
of the court’s construction that took the fins into account.
We praised the court for “carefully not[ing] the ornamen-
tal features that produced the overall ‘rocket-like’ appear-
ance . . . [and] properly limit[ing] the scope of the patent
to its overall ornamental visual impression, rather than to
the broader general design concept of a rocket-like tossing
ball.” Id.
    We followed a similar line of analysis in Richardson.
597 F.3d at 1293–94. The case concerned a multi-function
tool described in the patent as “compris[ing] several
elements that are driven purely by utility,” including a
hammer, crowbar, and stud climbing tool. Id. at 1294.
Those elements—i.e., the hammer’s flat head, the crow-
bar’s elongated shape, and the stud climbing tool’s jaw-
like shape—were well known in the art, and their basic
design was dictated by their respective functional purpos-
es. Id. But there were nevertheless ornamental aspects
of the design of those elements. The district court had
explained that the claim “protect[ed] the ornamental
aspects of Richardson’s design, which include, among
other things, the standard shape of the hammer-head, the
SPORT DIMENSION, INC.   v. THE COLEMAN COMPANY, INC.      7



diamond-shaped flare of the crow-bar and the top of the
jaw, the rounded neck, the orientation of the crowbar
relative to the head of the tool, and the plain, undecorated
handle.” Richardson v. Stanley Works, Inc., 610 F. Supp.
2d 1046, 1050 (D. Ariz. 2009), aff’d, 597 F.3d 1288. Our
court agreed with the district court’s approach that lim-
ited the claim to these ornamental aspects of the other-
wise functional elements. Richardson, 597 F.3d at 1293–
94. Under this construction, the claim in Richardson did
not protect the functional aspects of the design. Rather,
the court’s construction properly ensured that the claim
provided protection, albeit narrow, over those aspects of
the tool that were ornamental.
    In Ethicon Endo-Surgery, we construed a design pa-
tent on a surgical instrument. We explained that the
open trigger, torque knob, and activation button of the
instrument were functional. Ethicon Endo-Surgery, Inc.,
796 F.3d at 1334. And we construed the claim to elimi-
nate the functional aspects of the design but to permit
coverage of the ornamental aspects of the design. In
rejecting the district court’s claim construction, we disa-
greed with its conclusion that the claim had no scope. Id.
While we agreed that certain elements of the device were
functional, their functionality did not preclude those
elements from having protectable ornamentation. We
explained that, “although the Design Patents do not
protect the general design concept of an open trigger,
torque knob, and activation button in a particular config-
uration, they nevertheless have some scope—the particu-
lar ornamental designs of those underlying elements.” Id.
    In OddzOn, Richardson, and Ethicon, we construed
design patent claims so as to assist a finder of fact in
distinguishing between functional and ornamental fea-
tures. But in no case did we entirely eliminate a struc-
tural element from the claimed ornamental design, even
though that element also served a functional purpose.
8       SPORT DIMENSION, INC.   v. THE COLEMAN COMPANY, INC.



    The district court’s construction in this case conflicts
with that principle of design patent claim construction
because it eliminates whole aspects of the claimed design.
In its construction, the district court improperly excluded
the left and right armband and the torso side tapering:
    The ornamental design for a personal flotation
    device, as shown and described in Figures 1–8, ex-
    cept the left and right armband, and the side torso
    tapering, which are functional and not ornamen-
    tal.
J.A. 3 (emphasis added). The court explained that the
armbands and tapered torso “serve a functional rather
than ornamental purpose,” and thus excluded them from
the claim scope. Id.
    Coleman disputes the court’s ultimate construction
and its finding that the armbands and tapered torso are
functional. While we agree with Coleman that the court’s
ultimate construction was improper under our law, we
disagree with Coleman’s assertion that the armbands and
side torso tapering do not serve a functional purpose. As
the district court correctly pointed out, Coleman’s arm-
bands and tapered side torso designs meet several of the
factors we announced in PHG Technologies, LLC v.
St. John Cos., for determining whether a design claim
was dictated by function, including:
    whether the protected design represents the best
    design; whether alternative designs would ad-
    versely affect the utility of the specified article;
    whether there are any concomitant utility pa-
    tents; whether the advertising touts particular
    features of the design as having specific utility;
    and whether there are any elements in the design
    or an overall appearance clearly not dictated by
    function.
SPORT DIMENSION, INC.   v. THE COLEMAN COMPANY, INC.      9



469 F.3d 1361, 1366 (Fed. Cir. 2006) (quoting Berry
Sterling Corp. v. Pescor Plastics, Inc., 122 F.3d 1452, 1455
(Fed. Cir. 1997)). Although we introduced these factors to
assist courts in determining whether a claimed design
was dictated by function and thus invalid, they may serve
as a useful guide for claim construction functionality as
well.
     Applied here, the PHG factors indicate that the design
patent’s armbands and side torso tapering serve a func-
tional purpose. For example, the district court examined
alternative personal flotation device designs and conclud-
ed that Coleman’s armband and torso tapering represent-
ed the best available design for a personal flotation
device. The court found that Coleman filed a co-pending
utility patent disclosing the design patent’s armbands and
torso tapering and touting the utility of those features.
And it found Coleman to have promoted the particular
utility of the armbands and tapered torso in its adver-
tisements. We do not disagree with these findings. Nor
do we disagree with the district court’s conclusion that the
armbands and tapered side torso serve a functional pur-
pose.
    Nonetheless, even though we agree that certain ele-
ments of Coleman’s design serve a useful purpose, we
reject the district court’s ultimate claim construction. The
district court eliminated the armbands and side torso
tapering from the claim entirely, so its construction runs
contrary to our law. Here, as in Ethicon, “the district
court’s construction of the Design Patents to have no
scope whatsoever fails to account for the particular orna-
mentation of the claimed design and departs from our
established legal framework for interpreting design
patent claims.” Ethicon Endo-Surgery, 796 F.3d at 1334.
Moreover, design patents protect the overall ornamenta-
tion of a design, not an aggregation of separable elements.
Richardson, 597 F.3d at 1295 (noting that “discounting of
functional elements must not convert the overall in-
10      SPORT DIMENSION, INC.   v. THE COLEMAN COMPANY, INC.



fringement test to an element-by-element comparison”).
By eliminating structural elements from the claim, the
district court improperly converted the claim scope of the
design patent from one that covers the overall ornamenta-
tion to one that covers individual elements. Here, the
district court erred by completely removing the armbands
and side torso tapering from its construction.
    We thus look to the overall design of Coleman’s per-
sonal flotation device disclosed in the D’714 patent to
determine the proper claim construction. The design
includes the appearance of three interconnected rectan-
gles, as seen in Figure 2. It is minimalist, with little
ornamentation. And the design includes the shape of the
armbands and side torso tapering, to the extent that they
contribute to the overall ornamentation of the design. As
we discussed above, however, the armbands and side
torso tapering serve a functional purpose, so the fact
finder should not focus on the particular designs of these
elements when determining infringement, but rather
focus on what these elements contribute to the design’s
overall ornamentation. Because of the design’s many
functional elements and its minimal ornamentation, the
overall claim scope of the claim is accordingly nar-
row. See Ethicon Endo-Surgery, 796 F.3d at 1334 (endors-
ing a “limited” claim scope for a design with functional
elements).
    We therefore reject the district court’s claim construc-
tion, vacate the stipulated judgment of noninfringement,
and remand for consideration of infringement and, if
necessary, validity consistent with the proper claim
construction. In turn, nothing in this opinion should
foreclose any pre-trial resolution of the infringement issue
that is otherwise substantively and procedurally appro-
priate. Cf. id. at 1337 (affirming district court’s grant of
summary judgment of noninfringement of design patent).
SPORT DIMENSION, INC.   v. THE COLEMAN COMPANY, INC.    11



                              B.
     Coleman also challenges the district court’s exclusion
of its expert, Peter Bressler. We review a district court’s
exclusion of expert testimony under the law of the region-
al circuit, here the Ninth Circuit. Proveris Sci. Corp. v.
Innovasystems, Inc., 536 F.3d 1256, 1267 (Fed. Cir. 2008).
The Ninth Circuit reviews a district court’s exclusion of
an expert for an abuse of discretion. Cabrera v. Cordis
Corp., 134 F.3d 1418, 1420 (9th Cir. 1998).
     District court judges perform a gatekeeping role for
expert testimony. They must ensure that expert testimo-
ny is reliable and that the testimony “relate[s] to scien-
tific, technical or other specialized knowledge, which does
not include unsubstantiated speculation and subjective
beliefs.” Diviero v. Uniroyal Goodrich Tire Co., 114 F.3d
851, 853 (9th Cir. 1997) (citing Daubert v. Merrell Dow
Pharm., Inc., 509 U.S. 579, 590 (1993)); see also
Fed. R. Evid. 702.
     The district court here excluded Mr. Bressler, an in-
dustrial design consultant with four decades of industry
experience, because he had “no experience whatsoever in
the field of [personal flotation devices].” J.A. 27. The
record supports the district court’s conclusion. Mr. Bress-
ler, when asked to evaluate Sport Dimension’s expert’s
testimony on one aspect of the device’s function, stated:
“I’m not an expert on personal flotation devices.” Appel-
lee’s Br. 45. His proposal for alternative armband de-
signs, by Mr. Bressler’s admission, was based on his
“imagination.” Id. at 45–46. And he further admitted
that he had no work experience with wearable buoyancy
devices before serving as an expert. Id. at 45–47. In light
of Mr. Bressler’s admitted inexperience and unfamiliarity
with the very subject on which Coleman sought to rely on
his testimony, the district court did not abuse its discre-
tion in excluding his testimony. See Cabrera, 134 F.3d at
1420.
12       SPORT DIMENSION, INC.   v. THE COLEMAN COMPANY, INC.



                       CONCLUSION
    For the reasons stated above, we reject the court’s
claim construction, vacate its judgment of non-
infringement, affirm its exclusion of Coleman’s expert,
and remand for proceedings consistent with this opinion.
  AFFIRMED-IN-PART, VACATED-IN-PART, AND
                REMANDED
                           COSTS
     No costs.
