Smartrend Manufacturing Group (smg), Inc. v. Opti-Luxx Inc.

United States Court of Appeals
for the Federal Circuit
______________________
SMARTREND MANUFACTURING GROUP (SMG),
INC.,
Plaintiff-Appellee
v.
OPTI-LUXX INC.,
Defendant-Appellant
______________________
2024-1616, 2024-1650
______________________
Appeals from the United States District Court for the
Western District of Michigan in Nos. 1:21-cv-01009-HYJ-
RSK, 1:22-cv-00915-HYJ-RSK, Judge Hala Y. Jarbou.
______________________
Decided: November 13, 2025
______________________
T HOMAS W. CUNNINGHAM , Brooks Kushman PC, Royal
Oak, MI, argued for plaintiff-appellee. Also represented by
J OHN P. RONDINI, D USTIN ZAK.
G AETAN G ERVILLE -REACHE , Warner Norcross & Judd
LLP, Grand Rapids, MI, argued for defendant-appellant.
Also represented by D OUGLAS A. D OZEMAN; VITO
CIARAVINO, Detroit, MI.
______________________
Before D YK, L INN, and STARK, Circuit Judges.
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D YK, Circuit Judge.
Smartrend Manufacturing Group (SMG), Inc. (“Smar-
trend”) brought suit against Opti-Luxx Inc. (“Opti-Luxx”)
for infringement of two patents: U.S. Design Patent
No. D932,930 (the “D930 patent”) and U.S. Patent
No. 11,348,491 (the “’491 patent”). After trial, the jury
found that Opti-Luxx infringed both patents. The district
court denied Opti-Luxx’s motion for judgment as a matter
of law (“JMOL”) and issued a permanent injunction. Opti-
Luxx appeals.
With respect to the D930 patent, we conclude that
Opti-Luxx forfeited its objection to Smartrend’s expert tes-
timony on infringement, but we conclude that the district
court erred in its construction of the term “transparency,”
and that a new trial is necessary. With respect to the
’491 patent, we conclude that JMOL should have been
granted because no reasonable jury could have found in-
fringement under the doctrine of equivalents. Accordingly,
we reverse the judgment of infringement with regard to the
’491 patent, vacate the judgment as to the D930 patent,
and remand for a new trial on the issue of infringement of
the D930 patent. We also vacate the injunction.
BACKGROUND
This case involves two patents that are directed to an
illuminated school bus sign. Opti-Luxx’s product (the “ac-
cused product”) is a single-piece illuminated school bus
sign made up of a rigid plastic tub housing, an LED light
board, and a yellow lens with black lettering. The plastic
housing operates as the accused product’s frame and is not
separable from the rest of the sign. According to Opti-
Luxx, the black lettering on the accused product is totally
opaque and the yellow lens is translucent such that light
can pass through, but the LED light board behind it is not
clearly visible.
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I. T HE D930 P ATENT
The D930 patent claims “[t]he ornamental design for
an LED light panel, as shown and described.” J.A. 5557.
In the description, the D930 patent indicates that “oblique
shading lines visible in the front and perspective views de-
note transparency.” Id. The D930 patent contains 10 fig-
ures, three of which are shown below:
J.A. 5559.
Over Opti-Luxx’s objection, the district court construed
the D930 patent claim term “transparency” to mean both
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“transparent” and “translucent.” The jury was instructed
that “[t]he Court has found the word transparency to mean
both transparent and translucent. You must use this in-
terpretation of the oblique lines when you consider in-
fringement of the D930 design patent claim.” See Trial Tr.
vol. 3, 648:13–18, Smartrend Mfg. Grp. (SMG), Inc. v. Opti-
Luxx Inc., Nos. 1:21-cv-1009, 1:22-cv-915 (W.D. Mich.
Nov. 29, 2023).
At trial, in support of its infringement theory, Smar-
trend moved to recognize Mr. York as an expert in “LED
lighting and illuminated signage.” J.A. 1697 ll. 20–22.
Then, when Mr. York was admitted as an expert witness,
Opti-Luxx did not object. When Mr. York began testifying
as to the perspective of an ordinary observer with regard to
the D930 patent, Opti-Luxx objected to his testimony
based on his purported lack of qualifications. The district
court overruled this objection, and the jury subsequently
found infringement.
II. T HE ’491 P ATENT
Claim 1 of the ’491 patent is the only independent
claim of the patent and recites:
1. An illuminated school bus sign for direct mount-
ing on a school bus, the sign comprising:
opaque lettering positioned on or over a front
surface of a translucent panel;
an opaque rear panel situated opposite to the
translucent panel in spaced relation therefrom
to define a space therebetween;
a light source comprising a plurality of LEDs
positioned in the space adjacent to the rear
panel and pointing towards a front of the sign;
and
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frame surrounding a perimeter of the translu-
cent panel and forming a perimeter of the sign
for mounting the sign to the school bus,
wherein the translucent panel is spaced by
a spacer from the LEDs thereby creating a
gap between the LEDs and the translucent
panel,
wherein the spacer surrounds the LEDs
and supports a rear surface of the translu-
cent panel along the entire perimeter of the
translucent panel, and
wherein the entire perimeter of the trans-
lucent panel is sealed in a weather-tight
manner by a weather-tight seal between
the translucent panel and the spacer.
’491 patent, col. 22 l. 51–col. 23 l. 6.
The district court construed the claim term “frame” to
be “a separate and distinct” component. J.A. 77. The dis-
trict court based its construction on the intrinsic evidence
in the patent’s specification. Because the accused product
does not have a separate frame, the district court granted
summary judgment as to literal infringement but denied
summary judgment as to doctrine of equivalents infringe-
ment. The trial proceeded under a theory of doctrine of
equivalents infringement as to this claim limitation.
At trial, Mr. York testified that the accused product’s
integrated frame performed the same function as the
’491 patent’s claimed frame because it “forms a perimeter
of the sign for mounting to the school bus,” J.A. 1736 ll. 15–
20, even though he conceded that it did not perform other
functions discussed in the patent. Opti-Luxx argued that
this concession was fatal to Smartrend’s doctrine of equiv-
alents theory of infringement because the accused prod-
uct’s frame did not perform the required functions. The
district court rejected this contention and determined that
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the required function was an issue of fact for the jury ra-
ther than for the court to decide. The jury found infringe-
ment and subsequently the district court denied Opti-
Luxx’s motion for JMOL with regard to the ’491 patent.
Opti-Luxx timely appeals. We have jurisdiction under
28 U.S.C § 1295(a)(1).
D ISCUSSION
With respect to the D930 patent, Opti-Luxx argues
that the district court erred in construing the term “trans-
parency” and in admitting Mr. York’s testimony as to the
perspective of an ordinary observer. With respect to the
’491 patent, Opti-Luxx argues that the court erred in deny-
ing Opti-Luxx’s motion for JMOL because no reasonable
juror could have found that the accused product performed
the functions disclosed in the patent specification. Smar-
trend argues that we can affirm the judgment of infringe-
ment by rejecting the district court’s construction of
“frame” and finding literal infringement of the ’491 patent
by the accused product.
I. T HE D930 PATENT
A. EXPERT T ESTIMONY
Opti-Luxx objects to the admission of Mr. York’s expert
testimony regarding infringement of the D930 patent. We
review a district court’s admission of an expert witness for
abuse of discretion. Sundance, Inc. v. DeMonte Fabricating
Ltd., 550 F.3d 1356, 1360 (Fed. Cir. 2008). To prove design
patent infringement, a patentee must demonstrate that the
accused product “embod[ies] the patented design or any col-
orable imitation thereof.” Egyptian Goddess, Inc. v. Swisa,
Inc., 543 F.3d 665, 678 (Fed. Cir. 2008) (en banc) (quoting
Goodyear Tire & Rubber Co. v. Hercules Tire & Rubber Co.,
162 F.3d 1113, 1116–17 (Fed. Cir. 1998)). Whether a prod-
uct infringes a design patent hinges on whether an ordi-
nary observer would consider the two designs to be
substantially the same. Top Brand LLC v. Cozy Comfort
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Co., 143 F.4th 1349, 1358 (Fed. Cir. 2025) (quoting
Gorham Co. v. White, 81 U.S. 511, 528 (1871)). An ordi-
nary observer is the principal purchaser of a particular
product. Arminak & Assocs. v. Saint-Gobain Calmar, Inc.,
501 F.3d 1314, 1322 (Fed. Cir. 2007) (quoting Gorham,
81 U.S. at 528), abrogated on other grounds by, Egyptian
Goddess, 543 F.3d 665. At trial, Mr. York testified that an
ordinary observer for the purposes of the D930 patent is a
school bus dealer or the person making the purchasing de-
cision for a school district’s school bus fleet, a definition
that the parties do not contest on appeal. For the purposes
of Opti-Luxx’s motions, the district court “consider[ed] the
school district as the ordinary observer.” J.A. 52.
Although expert testimony is not always required to
elucidate the perspective of an ordinary observer, see
Braun Inc. v. Dynamics Corp. of Am., 975 F.2d 815, 821
(Fed. Cir. 1992), it is of course permitted if the intrinsic ev-
idence does not resolve the interpretive question, and
Smartrend chose to present expert testimony on the ordi-
nary observer’s perspective. Mr. York conceded that he is
not an ordinary observer himself, nor has he worked with
ordinary observers before. However, Mr. York did testify
that he had experience working in the automotive and
transportation industries, was familiar with the relevant
regulations that applied to school buses, and was an expert
in lighting systems and signage.
We have not yet had the occasion to decide what exactly
qualifies an expert witness to testify as to the perspective
of the ordinary observer. In the utility patent context, an
expert witness may testify as to the perspective of a person
of ordinary skill in the art (“POSA”) even if the expert pos-
sesses extraordinary skill. See FastShip, LLC v. United
States, 968 F.3d 1335, 1340 (Fed. Cir. 2020) (“An attack [on
an expert] on the grounds that he is not a person of ordi-
nary skill in the art is meritless.” (alteration in original;
internal quotation marks omitted)). However, for such an
extraordinary expert’s testimony to be relevant, the expert
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must establish familiarity with the perspective of a POSA.
See Ruiz v. A.B. Chance Co., 234 F.3d 654, 667 (Fed. Cir.
2000) (remanding where it was unclear whether a highly
qualified expert’s testimony was relevant to the perspec-
tive of a POSA); see also Kyocera Senco Indus. Tools Inc.
v. Int’l Trade Comm’n, 22 F.4th 1369, 1376–77 (Fed. Cir.
2022) (“To offer expert testimony from the perspective of a
skilled artisan in a patent case—like for claim construc-
tion, validity, or infringement—a witness must at least
have ordinary skill in the art. Without that skill, the wit-
ness’ opinions are neither relevant nor reliable.”); Robert
A. Matthews, Jr., Annotated Patent Digest § 44.66 (“Even
though experts may be of extraordinary skill, generally
their opinions have relevance only if the opinions show the
understanding of one of ordinary skill, not the personal un-
derstanding of the expert.”). It seems logical that these
same principles will apply in a design patent context—such
that expert witnesses may possess knowledge beyond that
of ordinary observers yet still testify as to the perspective
of an ordinary observer, provided the expert can establish
familiarity with that perspective.
We need not decide this today because the district court
correctly determined that Opti-Luxx forfeited its objection
to Mr. York’s testimony. Well before the time of the voir
dire, Mr. York had described his proposed testimony in his
expert report, including his analysis of the ordinary ob-
server’s perspective. The report ultimately concluded that
“an ordinary observer, giving the attention a purchaser of
signs usually gives, would consider the [accused product]
as a whole to be substantially similar in appearance as the
claimed design.” J.A. 547. When Smartrend moved to ad-
mit Mr. York as an expert witness, Opti-Luxx did not ob-
ject. Because Opti-Luxx had knowledge of Mr. York’s
anticipated testimony on the ordinary observer’s perspec-
tive, if Opti-Luxx wished to prevent the testimony, it was
required to object that Mr. York was not qualified to testify
to that perspective before the district court ruled on his
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qualifications. The district court did not err in allowing his
testimony.
B. CLAIM CONSTRUCTION OF “T RANSPARENCY ”
Opti-Luxx also argues that the district court applied an
erroneous claim construction to the D930 patent. We re-
view a district court’s claim construction based on intrinsic
evidence de novo and any underlying factual findings based
on extrinsic evidence for clear error. Apple Inc. v. Wi-LAN
Inc., 25 F.4th 960, 967 (Fed. Cir. 2022). Design patents are
directed towards new, original and ornamental designs.
35 U.S.C. § 171(a). As opposed to a utility patent, which
protects the functional aspects of an invention, a design pa-
tent protects “the ornamental or aesthetic features of a de-
sign.” Carman Indus., Inc. v. Wahl, 724 F.2d 932, 939 n.13
(Fed. Cir. 1983); accord Sport Dimension, Inc. v. Coleman
Co., 820 F.3d 1316, 1320 (Fed. Cir. 2016). “Design patents
are given narrow scope.” Top Brand, 143 F.4th at 1358.
A patented design may be claimed “as shown” or “as
shown and described.” 37 C.F.R. § 1.153(a). “[A]s a rule[,]
the illustration in the drawing views is its own best de-
scription.” Manual of Patent Examining Procedure
(“MPEP”) § 1503.01(II). Nevertheless, the MPEP states
that it is permissible for a patent applicant to use the de-
scription to set forth “the appearance of portions of the
claimed design which are not illustrated in the drawing
disclosure.” Id. § 1503.01(II)(A)(1). Where a design is
claimed “as shown and described”—as in the case of the
D930 patent—then the patent’s scope of protection is lim-
ited by the drawings and accompanying description in the
patent. See Curver Lux., SARL v. Home Expressions Inc.,
938 F.3d 1334, 1340–41 (Fed. Cir. 2019) (noting that
37 C.F.R. § 1.153(a) “permits claim language, not just illus-
tration alone” to identify the claimed article). The
D930 patent claims its design “as shown and described,”
the description being the inclusion of the reference to
“transparency.” J.A. 5557.
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On summary judgment, the district court determined
that “transparency” was “capable of being synonymous
with translucency.” J.A. 51. As noted earlier, the jury was
instructed, “[t]he Court has found the word transparency
to mean both transparent and translucent. You must use
this interpretation of the oblique lines when you consider
infringement of the D930 design patent claim.” Trial Tr.
vol. 3, 648:13–18, Smartrend, Nos. 1:21-cv-1009, 1:22-cv-
915 (W.D. Mich. Nov. 29, 2023).
The district court’s construction was erroneous. Deter-
mining the correct construction must begin with consider-
ation of the intrinsic evidence, which here includes the
important fact that the design claimed is “as shown and
described” in the specification, indicating to a POSA that
the scope of the claim is limited by both the drawings and
the accompanying description. See Curver Lux., 938 F.3d
at 1340–41. Here, the drawings use oblique shading—
which a POSA would know, from the MPEP, might “show
transparent, translucent and highly polished or reflective
surfaces,” MPEP § 1503.02(II)—which the description then
expressly narrows, stating the D930 patent’s “oblique
shading lines visible in the front and perspective views de-
note transparency.” J.A. 5557. The claims, here, are lim-
ited to surfaces that possess transparency. Transparency
is not synonymous with translucency and does not mean
both transparent and translucent.
In holding that “transparency” includes “translucent,”
the district court erred, requiring a new trial as to infringe-
ment. Smartrend appears to contend that on remand there
will be further claim construction necessary as to the
meaning of “transparency.” While the district court may
consider extrinsic evidence, such as the testimony of an ex-
pert witness, any testimony that is “at odds with . . . the
written record of the patent,” should be afforded no weight.
Phillips v. AWH Corp., 415 F.3d 1303, 1318 (Fed. Cir.
2005) (en banc) (quoting Key Pharms. v. Hercon Lab’ys
Corp., 161 F.3d 709, 716 (Fed. Cir. 1998)).
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There is no contention that the patent claims or speci-
fication here disclaim the plain and ordinary meaning of
“transparency” or that the patentee acted as a lexicogra-
pher. Under these circumstances, the jury must apply the
plain and ordinary meaning of the term. Thorner v. Sony
Comput. Ent. Am. LLC, 669 F.3d 1362, 1365 (Fed. Cir.
2012). Extrinsic evidence may not be used to arrive at a
construction that is contrary to the plain and ordinary
meaning.
It appears that Smartrend contends that the term
“transparency” has a special plain and ordinary meaning
in the art of light emitting devices. On remand, it will be
appropriate for the district court to determine whether
such an art-specific meaning of the term has been estab-
lished such that the jury should be instructed as to such a
meaning. But in this respect, we caution that “conclusory”
testimony by experts unsupported by reliable extrinsic ma-
terial—such as special-purpose dictionaries or other objec-
tive evidence—is insufficient. See Phillips, 415 F.3d
at 1318; see also Network Com., Inc. v. Microsoft Corp.,
422 F.3d 1353, 1361 (Fed. Cir. 2005) (disregarding expert
testimony because the expert “does not support his conclu-
sion with any references to industry publications or other
independent sources”); Wireless Agents LLC v. Sony Erics-
son Mobile Commc’ns AB, 189 F. App’x 965, 968 (Fed. Cir.
2006) (“We find that the expert’s statement is conclusory
and is unsupported by reference to any contemporaneous
document and therefore of no value in our claim construc-
tion analysis.”).
Because the district court erred in its claim construc-
tion, we reverse the district court’s construction—which
was that “the word transparency . . . mean[s] both trans-
parent and translucent”—vacate the judgment of infringe-
ment as to the D930 patent, and remand to the district
court for further proceedings.
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II. T HE ’491 P ATENT
A. CLAIM CONSTRUCTION OF “F RAME ”
Smartrend contends that the district court erred in its
claim construction of the term “frame” in the ’491 patent.
The district court construed the claim term “frame” to
mean “a separate, distinct component” from the remainder
of the sign, J.A. 77, and so instructed the jury, Trial Tr.
vol. 3, 643:12–14, Smartrend, Nos. 1:21-cv-1009, 1:22-cv-
915 (W.D. Mich. Nov. 29, 2023) (“I’ve determined that the
word frame is to be accorded its plain and ordinary mean-
ing but is also construed to be a separate and distinct com-
ponent.”). As the district court relied solely on intrinsic
evidence in construing “frame,” we review this claim con-
struction de novo. See Cal. Inst. of Tech. v. Broadcom Ltd.,
25 F.4th 976, 985 (Fed. Cir. 2022).
The court has the responsibility to interpret and con-
strue a utility patent, defining the scope of its claims. E.g.,
Markman v. Westview, 517 U.S. 370, 372 (1996). Claims
are construed based on the “ordinary and customary mean-
ing” that the term would have to a POSA at the time of the
invention. Phillips, 415 F.3d at 1312–13 (quoting Vitronics
Corp. v. Conceptronic, Inc., 90 F.3d 1576, 1582 (Fed. Cir.
1996)). This meaning is read both in the context of the
claim itself and “in the context of the entire patent, includ-
ing the specification.” Id. at 1313.
The district court correctly determined that the speci-
fication of the ’491 patent indicates that a “frame” is a sep-
arate and distinct component from the rest of the sign. See
Poly-Am., L.P. v. API Indus., Inc., 839 F.3d 1131, 1137
(Fed. Cir. 2016) (affirming district court’s narrow construc-
tion of claim based on “clear and unequivocal” intrinsic ev-
idence). The specification “repeatedly, consistently, and
exclusively,” see In re Abbott Diabetes Care Inc., 696 F.3d
1142, 1150 (Fed. Cir. 2012) (quoting Irdeto Access, Inc.
v. Echostar Satellite Corp., 383 F.3d 1295, 1300 (Fed. Cir.
2004)), refers to a “separate” mounting frame, see
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’491 patent, col. 2 ll. 5, 43; id. col. 4 l. 48; id. col. 7 l. 51; id.
col. 11 l. 41; id. col. 21 ll. 49–62, and also references a
“frameless” sign or “replaceable lens,” see id. col. 6 l. 15; id.
col. 7, ll. 43, 50, 56; id. col. 18 ll. 16, 46–50.
As we discuss later in more detail, the patent also de-
scribes functions of the claimed invention that cannot be
performed by a sign with an integrated frame. The patent
specification describes how the frame is “configured to re-
movably receive the sign,” ’491 patent, col. 2 ll. 6–7, so that
“service or replacement of the sign can be performed with-
out having to remove the entire installation” from the ve-
hicle, id. col. 11 ll. 11–13, and a vehicle manufacturer could
easily insert customized signage into mounted frames, id.
col. 11 ll. 41–67.
We agree with the district court that the term “frame”
in the context of the ’491 patent refers to a frame that is
separate and distinct from the sign panel. In our review,
“nothing suggests . . . that the claimed [device] can include”
signs with integrated frames and “[i]nstead, [the] patent[]
consistently show[s] the opposite.” See Abbott Diabetes,
696 F.3d at 1150. We accordingly reject Smartrend’s argu-
ment that the district court erred in its claim construction
and that we can affirm the judgment of infringement by
finding literal infringement of the ’491 patent.
B. D OCTRINE OF E QUIVALENTS I NFRINGEMENT
Opti-Luxx argues that the district court erred in failing
to grant JMOL on the issue of doctrine of equivalents in-
fringement. “The doctrine of equivalents prevents an ac-
cused infringer from avoiding infringement by changing
only minor or insubstantial details of a claimed invention
while retaining their essential functionality.” Sage Prods.,
Inc. v. Devon Indus., Inc., 126 F.3d 1420, 1424 (Fed. Cir.
1997); accord Eli Lilly & Co. v. Hospira, Inc., 933 F.3d
1320, 1335 (Fed. Cir. 2019). Under this theory, “a product
or process that does not literally infringe upon the express
terms of a patent claim may nonetheless be found to
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infringe if there is equivalence between the elements of the
accused product or process and the claimed elements of the
patented invention.” DePuy Spine, Inc. v. Medtronic So-
famor Danek, Inc., 469 F.3d 1005, 1016 (Fed. Cir. 2006) (in-
ternal quotation marks omitted) (quoting Warner-
Jenkinson Co. v. Hilton Davis Chem. Co., 520 U.S. 17, 21
(1997)).
Although there are two different ways that this Court
has phrased the equivalence test, each articulation “aim[s]
to investigate the same ‘essential inquiry.’” NexStep, Inc.
v. Comcast Cable Commc’ns, LLC, 119 F.4th 1355, 1370
(Fed. Cir. 2024) (quoting Warner-Jenkinson, 520 U.S.
at 40). Doctrine of equivalents infringement is found when
the “differences between the claimed invention and the ac-
cused device or process are ‘insubstantial.’” Tex. Instru-
ments Inc. v. Cypress Semiconductor Corp., 90 F.3d 1558,
1563–64 (Fed. Cir. 1996). The function-way-result test
asks whether the accused product “performs substantially
the same function in substantially the same way to obtain
the same result.” Graver Tank & Mfg. Co. v. Linde Air
Prods. Co., 339 U.S. 605, 608 (1950). Both parties here
agree that a function-way-result framework is an appropri-
ate articulation of the equivalence test in this case. Under
the function-way-result test, for a patentee to prevail, the
patentee must demonstrate equivalence as to each claimed
element of the patented invention, Lockheed Martin Corp.
v. Space Sys./Loral, Inc., 324 F.3d 1308, 1321 (Fed. Cir.
2003), with particularized testimony and linking argu-
ment, VLSI Tech. LLC v. Intel Corp., 87 F.4th 1332, 1343
(Fed. Cir. 2023).
We review the denial of a motion for JMOL de novo.
Bettcher Indus. v. Bunzl USA, Inc., 661 F.3d 629, 638
(Fed. Cir. 2011) (applying Sixth Circuit law). JMOL is ap-
propriate if no reasonable, properly instructed jury could
have found equivalence between each claimed element and
the accused product’s corresponding feature. Lab’y Corp.
of Am. Holdings v. Qiagen Scis., LLC, 148 F.4th 1350, 1361
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(Fed. Cir. 2025). In undertaking this analysis, we must
take the evidence in the light most favorable to the non-
moving party, here Smartrend. See Sundance, 550 F.3d
at 1365 (applying Sixth Circuit law).
Whether an accused product performs the same func-
tion as the function disclosed in the patent is a question of
fact. Intendis GMBH v. Glenmark Pharms. Inc., USA,
822 F.3d 1355, 1362 (Fed. Cir. 2016). We have held “that
the function-way-result test focuses on ‘an examination of
the claim and the explanation of it found in the written de-
scription of the patent.’” Stumbo v. Eastman Outdoors,
508 F.3d 1358, 1364–65 (Fed. Cir. 2007) (quoting AquaTex
Indus., Inc. v. Techniche Sols., 479 F.3d 1320, 1326
(Fed. Cir. 2007)). In determining the function disclosed in
the patent, “a patent’s disclosure is relevant and can at
times be dispositive.” Intendis, 822 F.3d at 1362. Thus,
the intrinsic evidence in a patent may establish the func-
tion of a claimed element. For example, in Hill-Rom Co.
Inc. v. Kinetic Concepts, Inc., we looked to the specification
to define the function of a claim element (a “cushion”) and
concluded that the specification “clearly teaches that one of
the major objectives of the cushions recited in the claims is
to provide support for the patient.” 209 F.3d 1337, 1341
(Fed. Cir. 2000). Because the accused product in question
did not perform that function, the district court properly
found that there was no infringement under the doctrine of
equivalents. Id. at 1343.
If a patent is “silent” as to the function, way, or result
of a claim limitation, “we should turn to the ordinarily
skilled artisan.” Intendis, 822 F.3d at 1362 (quoting
Stumbo, 508 F.3d at 1364–65). In this case, the patent was
not silent as to the function of the separate and distinct
frame. Indeed, the claim language expressly claims a
“frame surrounding a perimeter of the translucent panel
and forming a perimeter of the sign for mounting the sign
to the school bus.” ’491 patent, claim 1. Further, as the
district court acknowledged, the specification of the
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’491 patent “extols the virtues of its separate mounting
frame.” J.A. 75. For example, because the frame is “con-
figured to removably receive the sign,” ’491 patent, col. 2
ll. 6–7, “service or replacement of the sign can be performed
without having to remove the entire installation” from a
vehicle, id. col. 11 ll. 11–13. This way, “[s]igns may there-
fore be replaced in the event of failure, or can be swapped
out for signs with different school bus indicia in the event
of an intended service type change from school bus to activ-
ity bus . . . or in the event that the bus is being transferred
to a service area with different language requirements.”
Id. col. 11 ll. 30–35. The signage inserts can then be re-
used “without the indirectly-mounted sign having been
marred by any drilled holes or other defects that would oth-
erwise be introduced by direct-mounting techniques.” Id.
col. 11 ll. 35–40. Having a separate frame also allows a
manufacturer to efficiently customize a vehicle for a cus-
tomer by pre-fabricating various signs that can be easily
inserted into mounted frames. Id. col. 11 ll. 41–67. None
of these functions can be performed by a sign with an inte-
grated frame.
Smartrend points to one sentence in the ’491 patent to
assert that the patent contemplates frame embodiments
where the frame is “permanently affixed” to the sign. Ap-
pellee’s Br. 39–40. The specification states that “[i]n some
embodiments, the frame may be a single piece frame
whereby the sign is enclosed by means of intentional defor-
mation of the frame (crimping, stamping, pressing, etc.).”
’491 patent, col. 15 ll. 6–9. It is not clear that this sentence
discloses a version of the sign where the frame is “perma-
nently affixed,” Appellee’s Br. 42. Even if we assumed that
this sentence disclosed an embodiment of the frame that
eventually became permanently affixed, it would still per-
form the function of allowing a manufacturer to easily cus-
tomize vehicles for sale because the frame would have to be
sealed around a selected sign panel. As the district court
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noted,1 this sentence still clearly envisions a system with a
sign and frame that are separate components.2 The speci-
fication established the function of the separate frame.
The testimony of Mr. York (Smartrend’s expert) cannot
contradict the patent’s description of the function.
Mr. York testified that the accused product’s integrated
frame “performs exactly the same function” as the ’491 pa-
tent’s claimed frame, in the same way, to achieve the same
result, because it analogously performs the functions of
“[s]urrounding” the sign and “form[ing] a perimeter of the
sign for mounting to the school bus.” J.A. 1736 ll. 15–25;
accord J.A. 1739 l. 19–1740 l. 3 (“It just does the same
thing. It gets the same result. It gets the job done in the
same way.”). As we have explained, however, the function
of the frame—which the district court properly construed
as being required to be separate and distinct from the re-
mainder of the sign—is far more than just “surrounding”
and “mounting.” On cross examination, Mr. York admitted
1 In considering whether this section of the specifica-
tion disclosed an integrated, rather than separate frame,
the district court noted that such a reading would
“weaken[] the claimed benefit of the separate mounting
frame structure by presumably making it more difficult to
remove the sign assembly from the mount.” J.A. 76.
2 Smartrend also points out that the specification
states, “Other embodiments that are within the present
disclosure include a mounting frame that uses double side
adhesive, glue, fasteners and other suitable mounting
means.” ’491 patent, col. 18 ll. 36–38. But in context, this
refers to how the frame attaches to a vehicle, not how it
encloses the sign within the frame. The preceding sentence
makes this clear. Id. col. 18 ll. 33–36 (“[I]n some embodi-
ments, the mounting frame may be a frame for mounting
on the internal or external surfaces of a vehicle window us-
ing suction cups.” (emphasis added)).
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that the accused product does not allow for the frame to
removably receive the sign or enable a manufacturer to
easily customize vehicles with different signage. See
J.A. 1831 ll. 13–16; J.A. 1832 ll. 16–23 (“It’s not capable of
doing that.”).
The undisputed evidence shows that the accused device
does not perform the required functions. The patent indi-
cates that the claimed invention can “removably receive
the sign” so that the signs can be exchanged, customized,
or serviced without removing the entire installation. See
’491 patent, col. 2 ll. 6–10. Smartrend’s expert witness,
Mr. York, conceded that the accused product is “not capa-
ble of doing that.” J.A. 1831 l. 13–1832 l. 23. Therefore, no
reasonable jury could have found that the accused product
infringed the ’491 patent. We reverse the denial of JMOL
as to the finding of infringement of the ’491 patent.
CONCLUSION
For the foregoing reasons, we vacate the judgment of
infringement of the D930 patent and remand for further
proceedings consistent with this opinion. We reverse the
district court’s denial of JMOL as to the ’491 patent. The
injunction is vacated.
REVERSED-IN-PART, VACATED-IN-PART, AND
REMANDED
COSTS
Costs to Opti-Luxx.
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