Lambeth Magnetic Structures, LLC v. Seagate Technology (us) Holdings Inc., Seagate Technology, LLC

NOTE: This disposition is nonprecedential.
United States Court of Appeals
for the Federal Circuit
______________________
LAMBETH MAGNETIC STRUCTURES, LLC,
Plaintiff-Appellant
v.
SEAGATE TECHNOLOGY (US) HOLDINGS INC.,
SEAGATE TECHNOLOGY, LLC,
Defendants-Cross-Appellants
______________________
2023-1335, 2023-1346
______________________
Appeals from the United States District Court for the
Western District of Pennsylvania in No. 2:16-cv-00538-CB,
Judge Cathy Bissoon.
______________________
Decided: September 17, 2025
______________________
JEFFREY A. LAMKEN, MoloLamken LLP, Washington,
DC, argued for plaintiff-appellant. Also represented by
JENNIFER ELIZABETH FISCHELL, RAYINER HASHEM; DENISE
MARIE DE MORY, MICHAEL ELI FLYNN-O'BRIEN, RICHARD
CHENG-HONG LIN, Bunsow De Mory LLP, Redwood City,
CA.
DAVID J.F. GROSS, Faegre Drinker Biddle & Reath LLP,
Minneapolis, MN, argued for defendants-cross-appellants.
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LAMBETH MAGNETIC STRUCTURES, LLC v.
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Also represented by CHAD DROWN, KATHERINE S. RAZAVI,
KEVIN P. WAGNER.
______________________
Before REYNA, SCHALL, and HUGHES, Circuit Judges.
REYNA, Circuit Judge.
Lambeth Magnetic Structures, LLC appeals a district
court judgment of noninfringement of its U.S. Patent
No. 7,128,988. Lambeth argues that the district court er-
roneously construed the claim term “uniaxial symmetry
broken structure.” Seagate Technology (US) Holdings Inc.
and Seagate Technology, LLC cross-appeal, arguing that
the district court erred in denying judgment as a matter of
law on invalidity, because a reasonable jury could not have
found the patent enabled under 35 U.S.C. § 112. We deter-
mine that the district court’s judgment of noninfringement
was premised on an erroneous claim construction of the
disputed claim term. We vacate the judgment of nonin-
fringement and dismiss the cross-appeal as improper. Be-
cause we determine that the proper construction of the
disputed claim term may affect the evidence and argu-
ments presented on enablement, we remand for a new trial
on both infringement and enablement under the proper
construction of “uniaxial symmetry broken structure.”
BACKGROUND
I. The ’988 Patent
Dr. David N. Lambeth (“Dr. Lambeth”) originally as-
signed U.S. Patent No. 7,128,988 (“’988 patent”) to Lam-
beth Systems. ’988 patent; see also J.A. 30234. That
patent is currently assigned to Lambeth Magnetic Struc-
tures, LLC (“LMS”). J.A. 12585. The patent relates to “[a]
thin film magnetic structure, magnetic devices, and
method of producing the same.” Id., Abstract. One use
case for the invention is in “magnetic recording media” de-
vices, id. at 6:65–7:3, 32:33–34, such as hard disk drives
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(“hard drives”). See J.A. 24. In “a traditional hard disk
system,” a “magnetic head passes over the media data,” i.e.,
the hard disk. ’988 patent, 7:12–16, 35–56. To record in-
formation on the disk, the magnetic head can apply a mag-
netic field that alters the media data, see id. at 7:35–38; in
this case, the head is referred to as a “recording head,” see
id. at 7:12–20. The patent is directed to a particular “thin
film” magnetic material that can be used in such recording
heads. Id. at 12:58–66.
The patent describes what it purports to be a unique
structure for such a thin-film material. See id.
at 12:58–13:18. Specifically, the patent describes the
structure as including three features relevant to this ap-
peal. The first feature is that the structure includes “at
least one bcc-d layer which is magnetic.” Id. at claim 1. A
“bcc-d layer” is a layer of metallic crystals in which the
metal atoms are arranged in a “body centered cubic” or a
derivative thereof (“bcc-d” or “bcc’d”) manner; thus, “bcc”
refers to a type of crystal structure. Id. at 5:12–17,
14:64–67; see J.A. 24325. The patent provides that using a
bcc-d layer increases “saturation magnetization[]” in com-
parison to layers consisting of other types of crystal struc-
tures, thereby “allow[ing] new devices to be constructed”
with favorable properties such as “high magnetization.” Id.
at 13:2–8. According to Dr. Lambeth, for “magnetic record-
ing heads,” high magnetization allows the head to “put out
a stronger field towards the media.” J.A. 30138–39.
The second feature is that the bcc-d layer “form[s] a
uniaxial symmetry broken structure.” ’988 patent, claim 1.
“Uniaxial” as used in the patent refers to “uniaxial anisot-
ropy.” See id. at 1:45–60 (defining “uniaxial anisotropy”),
3:11–27 (referring to materials demonstrating uniaxial an-
isotropy as “uniaxial materials”). “Magnetic anisotropy”
(or simply “anisotropy”) occurs when a material can be
more easily magnetized in a particular direction. Id.
at 1:35–60. That is, the material has a “preferred direction,
or directions, of [magnetic] orientation.” Id. at 1:35–38. An
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anisotropic material is uniaxial when it has a single direc-
tion, the “easy axis,” along which magnetization is pre-
ferred, and a single different direction, the “hard axis,”
along which magnetization is not preferred, as the magnet-
ization angle is rotated by 180 degrees from a physical axis.
Id. at 1:35–60. In the context of a recording head, the pa-
tent explains that using a material that is uniaxially ani-
sotropic allows the head to be magnetized to turn away
from the media, i.e., the hard disk, after recording on it, to
avoid “generat[ing] noise” that may inadvertently over-
write nearby areas of the media. Id. at 7:32–67. Dr. Lam-
beth testified that he aimed to create a head with
properties such that, after recording on the media, the head
“turns back, so it doesn’t erase the media.” J.A. 30143.
The third relevant feature required by the claims is
that the structure is “symmetry broken.” ’988 patent,
claim 1. A symmetry-broken structure refers to a subset of
possible arrangements of the bcc-d “unit cells,” which com-
prise the crystal lattice that makes up the structure. Id.
at 11:33–49, 16:34–36. The bcc-d unit cells in the claimed
structure can be oriented in one of six directions or “vari-
ants” over a hexagonal template. Id. at 13:39–42,
14:48–58. A “symmetry broken structure” occurs when the
material does “not contain an equal amount of all six of”
the “bcc-d variants.” Id. at 23:38–41. According to the pa-
tent, “uniaxial behavior can result” from symmetry broken
structure. Id. at 23:50–24:8 (emphasis added).
On appeal, the claims at issue are claims 1, 3, 6, 7, 9,
17, 19, and 27–29 of the ’988 patent. Independent claim 1
is representative:
1. A magnetic material structure comprising:
a substrate;
at least one bcc-d layer which is magnetic, forming
a uniaxial symmetry broken structure; and
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at least one layer providing a . . . textured hexago-
nal atomic template disposed between said sub-
strate and said bcc-d layer.
Id. at claim 1 (emphasis added).
II. Procedural History
In 2016, LMS sued several hard drive manufacturers,
including Seagate Technology (US) Holdings Inc. and
Seagate Technology, LLC (collectively, “Seagate”), in the
United States District Court for the Western District of
Pennsylvania, alleging infringement of the ’988 patent.1 In
the complaint, LMS alleged that Seagate’s products “in-
fringe at least claims 1 and 27 of the ’988 patent, and de-
pendent claims thereof, including claims 6, 7, 9, 11, and
13.” J.A. 201.
In October 2017, the district court issued a Markman
order. J.A. 1–21. The district court construed the claim
term “uniaxial symmetry broken structure” as “a structure
that is uniaxial as a result of the structure being symmetry
broken.” J.A. 18–20 (emphasis added).
In October 2018, Seagate moved, in relevant part, for
summary judgment of invalidity due to inadequate written
description and noninfringement under 35 U.S.C. §§ 112
and 271. See J.A. 22, 157. Concurrently, LMS moved for
partial summary judgment in its favor on the issue of inva-
lidity. See J.A. 23, 157. In June 2019, the district court
issued a memorandum order that resolved Seagate’s and
LMS’s cross-motions for summary judgment. J.A. 22–74.
The district court found that genuine issues of material fact
1 The district court litigation also involved related
complaints filed by LMS against Western Digital Corpora-
tion and its subsidiaries and against Toshiba Corporation
and its subsidiaries. J.A. 196; see J.A. 1, 2 n.1. Those cases
are not at issue in this appeal.
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precluded summary judgment as to whether the ’988 pa-
tent was invalid for inadequate written description and
whether Seagate’s accused devices infringed the ’988 pa-
tent. J.A. 29–42. Thus, the district court denied Seagate
and LMS’s motions for summary judgment regarding writ-
ten description and Seagate’s motion for summary judg-
ment of noninfringement. J.A. 73–74.
The district court held trial from April 4 to 14, 2022.
On April 12, 2022, Seagate moved for judgment as a matter
of law (“JMOL”) on direct and indirect infringement, as
well as infringement under the doctrine of equivalents.
J.A. 31204–05. The district court granted JMOL with re-
spect to infringement under the doctrine of equivalents.
J.A. 31209. However, the district court did not grant
JMOL as to direct or indirect infringement, because there
was “sufficient evidence . . . that a reasonable jury could
conclude that the plaintiff wins.” Id. On April 13, 2022
LMS moved for JMOL on infringement and on Seagate’s
invalidity defenses, including lack of enablement under
§ 112. J.A. 31455–56. Concurrently, Seagate again moved
for JMOL on the issue of infringement and additionally
moved for JMOL on the issue of invalidity, including lack
of enablement. J.A. 31456–58. The district court denied
each party’s motions as to infringement because there were
“still issues of fact to be resolved by the jury with respect
to that issue.” J.A. 31458. The district court also denied
each party’s motion as to invalidity, including lack of ena-
blement, because “the jury [could] certainly find that the
patent is valid.” Id.
On April 14, 2022, the district court issued a written
order restating its denial of LMS’s and Seagate’s oral mo-
tions for JMOL as to infringement and invalidity (includ-
ing for lack of enablement), respectively. See J.A. 134. The
same day, the jury returned a verdict of noninfringement
of claims 1, 3, 6, 7, 9, 17, 19, and 27–29 of the ’988 patent,
and a verdict of no invalidity for all those claims.
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J.A. 84–85. The district court then entered judgment in fa-
vor of Seagate as to infringement. J.A. 87.
In May 2022, Seagate filed a renewed motion for JMOL
on infringement and a conditional motion for a new trial,
and LMS filed a renewed motion for JMOL on invalidity
under § 112 and a motion for a new trial. J.A. 193. In No-
vember 2022, the district court denied the parties’ renewed
JMOL motions and motions for a new trial. J.A. 88–90.
LMS appeals, and Seagate cross-appeals.2 We have ju-
risdiction under 28 U.S.C. § 1295(a)(1).
DISCUSSION
LMS argues that the district court misconstrued the
claim term “uniaxial symmetry broken structure,” and,
thus, we should vacate the judgment of noninfringement
and remand for a new trial on infringement. Seagate ar-
gues in its cross-appeal that it is entitled to JMOL of inva-
lidity for lack of enablement. Seagate also conditionally
argues that, if we vacate and remand for a new trial on in-
fringement, we should also order a new trial on invalidity.
2 Prior to oral argument, LMS submitted a motion to
dismiss Seagate’s cross-appeal as improper because
Seagate only “raised invalidity of the ’988 patent as an af-
firmative defense” and “did not assert any counterclaim
seeking a declaration of invalidity.” Appellant Motion to
Dismiss Cross-Appeal, 1–3 (emphasis in original). Seagate
filed a response, and LMS filed a reply. Response to Motion
to Dismiss Cross-Appeal; Reply in Support of Motion to
Dismiss Cross-Appeal. We issued an order “deferr[ing] to
the merits panel.” Order, Lambeth Magnetic Structures,
LLC v. Seagate Technology (US) Holdings, Inc. and
Seagate Technology LLC, Nos. 23-1335, 23-1346, at 2
(Fed. Cir. May 25, 2023) (ECF No. 20). We address LMS’s
motion herein.
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I. Claim Construction
LMS argues that the district court erred by construing
the claim term “uniaxial symmetry broken structure” as a
structure that is “uniaxial as a result of the structure being
symmetry broken.” Appellant’s Opening Br. 29–30 (cita-
tion modified). Seagate counters that LMS waived its right
to challenge this construction; that, regardless, the district
court’s construction was correct; and that any error in the
construction was harmless. Cross-Appellant’s Opening
and Response Br. 33–51.
A. Waiver
Seagate argues that LMS waived its right to challenge
the district court’s construction of “uniaxial symmetry bro-
ken structure” on appeal. Cross-Appellant’s Opening and
Response Br. 48–50. Seagate relies on statements in
LMS’s technical expert report and on LMS’s response to
one of Seagate’s motions in limine. Id. We disagree with
Seagate.
Generally, a party waives its challenge to a district
court’s construction of a claim term “by agreeing to that
portion of the adopted construction.” Abbott Lab’ys v.
Syntron Bioresearch, Inc., 334 F.3d 1343, 1352
(Fed. Cir. 2003) (finding waiver where the party “stated
during trial” that the “claim term is properly defined” (ci-
tation modified)). “When the claim construction is resolved
pre-trial, and the patentee presented the same position in
the Markman proceeding as is now pressed, a further ob-
jection to the district court’s pre-trial ruling may indeed
have been not only futile but unnecessary.” Cardiac Pace-
makers, Inc. v. St. Jude Med., Inc., 381 F.3d 1371, 1381
(Fed. Cir. 2004); see also O2 Micro Int’l Ltd. v. Beyond In-
novation Tech. Co., 521 F.3d 1351, 1359 (Fed. Cir. 2008);
Top Brand LLC v. Cozy Comfort Co. LLC, 143 F.4th 1349,
1355–56 (Fed. Cir. 2025).
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First, Seagate argues that LMS agreed to the district
court’s construction of “uniaxial symmetry broken struc-
ture” and thus waived any challenge to it, as evidenced in
LMS’s technical expert report. Cross-Appellant’s Opening
and Response Br. 48–49. In the report, LMS’s technical ex-
pert stated that, while “symmetry breaking can result in a
material with intrinsic uniaxial anisotropy,” such “[e]xter-
nal sources of anisotropy . . . are distinct from the focus of
the [’]988 patent, which concentrates on and claims the in-
vention of uniaxial anisotropy bcc-d thin film materials as
a result of symmetry breaking.” J.A. 12587 (emphasis
added); see Cross-Appellant’s Opening and Response
Br. 48–49. We disagree with Seagate’s assertion that this
statement in the expert report constitutes a waiver of
LMS’s claim construction position on appeal. LMS’s expert
noted that he merely relied on the district court’s construc-
tion of this term when formulating his technical conclu-
sions. J.A. 12589–90. Thus, LMS’s expert merely adopted
the district court’s claim construction for the purposes of
providing testimony, but he did not agree to it.
Second, Seagate argues that LMS agreed with the dis-
trict court’s construction when it intentionally abandoned
the position it initially advanced during claim construction.
Cross-Appellant’s Opening and Response Br. 49. Specifi-
cally, Seagate notes that, in response to one of Seagate’s
motions in limine, LMS stated that “[t]he Court’s claim
constructions do not require clarification” and that “LMS’s
experts applied those constructions and demonstrated that
the bcc-d layer of the claims forms a uniaxial, symmetry
broken structure that is uniaxial as a result of the sym-
metry broken structure.” J.A. 18326 (emphasis in origi-
nal); see Cross-Appellant’s Opening and Response Br. 49.
However, LMS’s statement was part of its argument that
Seagate sought to include “an improper additional limita-
tion” to the claims related to whether “the [bcc-d] layer as
a whole must form the uniaxial symmetry broken struc-
ture.” J.A. 18327–28 (citation modified) (emphasis added).
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As such, LMS’s statement merely recited the district
court’s claim construction of “uniaxial symmetry broken
structure” to argue that Seagate included an additional
limitation unrelated to the “as a result” construction.
There is no waiver here.
In sum, in both instances, LMS never “agree[d] to that
portion of the adopted construction” of “uniaxial symmetry
broken structure.” See Abbott Lab’ys, 334 F.3d at 1352.
Thus, LMS did not waive its claim construction position.
B. The “As a Result” Construction
According to LMS, the proper construction of “uniaxial
symmetry broken structure” is “a symmetry broken struc-
ture that is uniaxial.” Appellant’s Opening Br. 32. We
agree.
“Claim construction is ultimately a question of law.”
Evolusion Concepts, Inc. v. HOC Events, Inc., 22 F.4th
1361, 1365 (Fed. Cir. 2022). We review claim construction
de novo “based on intrinsic evidence . . . and review any
findings of fact regarding extrinsic evidence for clear er-
ror.” SpeedTrack, Inc. v. Amazon.com, 998 F.3d 1373, 1378
(Fed. Cir. 2021).
“[T]he words of a claim are generally given their ordi-
nary and customary meaning,” which is the “meaning that
the term would have to a person of ordinary skill in the art
in question at the time of the invention.” Phillips v. AWH
Corp., 415 F.3d 1303, 1312–13 (Fed. Cir. 2005) (en banc)
(citation modified). We consider the meaning of a claim
term in the context of the intrinsic evidence, “begin[ning]
with the language of the claims.” Iridescent Networks, Inc.
v. AT&T Mobility, LLC, 933 F.3d 1345, 1350
(Fed. Cir. 2019). If “the claim language is not sufficiently
clear on its face to provide guidance to a person of ordinary
skill in the art as to the meaning of the term,” we then “look
first to the specification, followed by the prosecution his-
tory, to determine the meaning of the term.” Id. at 1351.
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There are two exceptions in which we do not give the
words of a claim their ordinary and customary meaning as
understood by a person of ordinary skill in the art: (1) when
a patentee sets out a definition and acts as her own lexi-
cographer; and (2) when the patentee disavows the full
scope of a claim term either in the specification or during
prosecution. Thorner v. Sony Computer Ent. Am. LLC,
669 F.3d 1362, 1365 (Fed. Cir. 2012). To act as its own lex-
icographer, a patentee must clearly set forth a definition of
the disputed claim term other than its plain and ordinary
meaning. Id. It is not enough for a patentee to simply dis-
close a single embodiment or use a word in the same man-
ner in all embodiments, as the patentee must clearly
express an intent to redefine the term. Id.
Turning first to the claim language, the term “uniaxial
symmetry broken structure” provides that the structure be
“uniaxial” and “symmetry broken,” with no express state-
ment that the latter causes the former. See ’988 pa-
tent, claim 1. Such a causal connection would essentially
amount to a functional relationship. But there is nothing
in the claim language providing that the “uniaxial sym-
metry broken structure” is based on function. “Uniaxial”
and “symmetry broken” describe structural features of the
invention.3 Accordingly, the claim term cannot be read to
3 The district court construed “uniaxial” as “[h]aving
an anisotropy energy density function with only a single
maximum and a single minimum as the magnetization an-
gle is rotated by 180 degrees from a physical axis” and
“symmetry broken structure” as “[a] structure consisting of
unequal volumes or unequal amounts of the bcc-d variants
of a six variant system.” J.A. 28. These constructions are
not disputed on appeal. As construed, both claim terms re-
fer to structural features: the “energy density function” rel-
ative to a “physical axis,” and a “structure” based on bbc-d
variants. See id.
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include the requirement that the symmetry broken nature
of the structure causes the structure to be uniaxial.
The specification confirms the construction of the claim
term as structural, not as based on a causal function. To
the extent that the specification contains a limitation that
the symmetry broken nature of the structure must cause
the structure to be uniaxial, that would be a limitation
based on function. We cannot “import into the claim a func-
tion from the specification, particularly when the claim re-
cites only purely structural limitations.” Toro Co. v. White
Consol. Indus., Inc., 266 F.3d 1367, 1371 (Fed. Cir. 2001).
Here, as explained, the invention is “claimed in purely
structural terms” and thus “generally resists functional
limitation.” See id. In addition, lexicography does not ap-
ply, because the specification does not “clearly set forth”
any definition of “uniaxial symmetry broken structure.”
See Thorner, 669 F.3d at 1365.
Thus, we conclude that “uniaxial symmetry broken
structure” should be construed as “a symmetry broken
structure that is uniaxial.” Accordingly, the district court’s
construction, “a structure that is uniaxial as a result of be-
ing symmetry broken,” is erroneous.4
Seagate’s counterarguments are unpersuasive.
Seagate contends that grammar requires the causal con-
struction because, absent a comma or an “and” dividing the
4 While we do not reach extrinsic evidence, we note
that the district court limited its construction based on the
prosecution history of “the equivalent patent in the Euro-
pean Union,” European Patent No. 1435091. See J.A. 19,
2100. Our precedent, however, counsels against “indis-
criminate reliance on the prosecution of corresponding for-
eign applications in the claim construction analysis.” AIA
Eng’g Ltd. v. Magotteaux Int’l S/A, 657 F.3d 1264, 1279
(Fed. Cir. 2011).
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two adjectives “uniaxial” and “symmetry broken,” the for-
mer modifies the latter, thus indicating a causal link.
Cross-Appellant’s Opening and Response Br. 36–38. But
English grammar precepts support the construction of the
claim term as structural, not based on a causal function.
See In re Hyatt, 708 F.2d 712, 714 (Fed. Cir. 1983). Gram-
matical rules provide that the absence of an “intervening
comma or conjunction” between two adjectives preceding a
noun (here, “structure”) indicates that the adjectives are
“unrelated.” BRYAN A. GARNER, DICTIONARY OF MODERN
LEGAL USAGE 25 (2d ed. 1995) (emphasis added). We see
no reason why the absence of an intervening comma or
“and” makes it plain that the structure’s symmetry broken
nature must cause it to be uniaxial.
Seagate also asserts that “uniaxial symmetry broken
structure” is a “coined term” with “no ordinary or estab-
lished meaning” outside of the ’988 patent and invokes the
principle of claim construction that such a term “can only
be understood in the context of the specification.” Cross-
Appellant’s Opening and Response Br. 33–35 (citing, inter
alia, Honeywell Int’l Inc. v. Universal Avionics Sys. Corp.,
488 F.3d 982, 991 (Fed. Cir. 2007)). In Malvern Panalyti-
cal Inc. v. TA Instruments-Waters LLC, we discussed a dis-
trict court’s conclusion that a claim term “cannot be
construed broader than the disclosure in the specification”
because the term was a “coined term with no commonly un-
derstood meaning in the art.” 85 F.4th 1365, 1374
(Fed. Cir. 2023) (citation modified). We acknowledged that
we have “held that claim terms that have no plain or estab-
lished meaning to one of ordinary skill in the art ordinarily
cannot be construed broader than the disclosure in the
specification.” Id. (citation and quotations omitted). How-
ever, we emphasized that “[w]e have sparingly applied this
principle of construction in other cases.” Id. (citing, inter
alia, Honeywell, 488 F.3d at 991). We noted that “[t]he dis-
trict court’s analysis predominantly addressed whether”
the claim term at issue “ha[d] a plain and ordinary
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meaning broadly in the art.” Id. (emphasis added). We
contrasted this question of whether a claim term is “a
coined term . . . known in the art or readily understandable
to a skilled artisan,” with “the question of what plain and
ordinary meaning a term has in the context of a patent,”
and explained that the latter “is the focus of our analysis.”
Id. (citation omitted) (emphasis added).
Following Malvern, it is beyond the “focus of our anal-
ysis” to consider whether “uniaxial symmetry broken struc-
ture” has “an ordinary meaning outside of the asserted
patent[].” See id. (citation modified). Thus, to the degree
that “uniaxial symmetry broken structure” is a coined term
with no ordinary meaning outside of the ’988 patent, we
only consider “the question of what plain and ordinary
meaning a term has in the context of a patent.” Id. (empha-
sis added).
C. Prejudicial Error
Seagate contends that any error in the district court’s
claim construction was harmless because “the jury would
have reached the same noninfringement verdict regardless
of whether the district court was correct in its construction
of uniaxial symmetry broken structure.” Cross-Appellant’s
Opening and Response Br. 50 (quoting Verizon Servs. Corp.
v. Cox Fibernet Virginia, Inc., 602 F.3d 1325, 1342
(Fed. Cir. 2010)) (citation modified). Seagate asserts that
it presented (1) “extensive evidence that its accused de-
vices were not uniaxial, such that the condition precedent
for the ‘as a result’ language becoming relevant was never
met”; and (2) certain “grounds for non-infringement unre-
lated to the challenged construction.” Cross-Appellant’s
Opening and Response Br. 50–51 (Seagate’s emphasis).
Seagate fails to establish that the district court’s erro-
neous construction was harmless. Because the jury did not
indicate the basis for its finding of noninfringement, it can-
not be ascertained whether the jury only relied on grounds
unrelated to the district court’s construction of “uniaxial
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symmetry broken structure.” See J.A. 84–85. As a result,
it is unclear that “correction of the errors in a jury instruc-
tion on claim construction would not have changed the re-
sult, given the evidence presented.” See Teleflex, Inc. v.
Ficosa N. Am. Corp., 299 F.3d 1313, 1328 (Fed. Cir. 2002).
In other words, the jury verdict does not provide a clear
basis to find that the error was harmless.
Moreover, we have concluded that a district court’s er-
roneous claim construction is “prejudicial” when the de-
fendant “relied on the district court’s erroneous
construction for its argument that it does not infringe the
asserted claims.” Network-1 Techs., Inc. v. Hewlett-Pack-
ard Co., 981 F.3d 1015, 1025 (Fed. Cir. 2020). At trial,
Seagate argued that “[i]f you are getting anisotropy as a
result of other things, then you can’t infringe.” J.A. 31581.
Seagate therefore relied on the district court’s claim con-
struction to argue that its products do not infringe because
their uniaxial anisotropy is not caused by their structure
being symmetry broken. Thus, we conclude that the dis-
trict court’s misconstruction of “uniaxial symmetry broken
structure” was prejudicial.
II. Enablement
In its cross-appeal, Seagate argues that, based on the
evidence presented, a reasonable jury could not have found
the ’988 patent enabled. Cross-Appellant’s Opening and
Response Br. 72. Accordingly, Seagate argues that we
should reverse the district court’s denial of JMOL on inva-
lidity. Cross-Appellant’s Opening and Response Br. 71–79.
Alternatively, Seagate argues that, if we remand for a new
trial on infringement based on the district court’s errone-
ous claim construction, we should also order a new trial on
invalidity because a reasonable jury could not have found
the patent enabled and a broader claim construction would
affect the evidence and arguments presented on enable-
ment. Cross-Appellant’s Opening and Response Br. 79–80.
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A. Dismissal of the Cross-Appeal
LMS counters that the cross-appeal should be dis-
missed. Appellant’s Response and Reply Br. 46–47. We
agree and thus dismiss the cross-appeal.
Seagate prevailed in the district court proceedings that
are the subject of this appeal. As the party that prevailed,
Seagate cannot bring an appeal seeking to affirm this out-
come on a different basis, i.e., that the ’988 patent is invalid
for lack of enablement. See Therasense, Inc. v. Becton,
Dickinson & Co., 593 F.3d 1325, 1337 (Fed. Cir. 2010) (“[A]
cross-appeal is proper only when ‘acceptance of the argu-
ment it wishes to advance would result in a reversal or
modification of the judgment rather than an affirmance.’”
(quoting Bailey v. Dart Container Corp. of Michigan, 292
F.3d 1360, 1362 (Fed. Cir. 2002)). Indeed, Seagate admits
in its briefing that “invalidity is available to the Court as
an alternative basis to affirm the verdict.” Cross-Appel-
lant’s Opening and Response Br. 71. Moreover, Seagate
was not a declaratory plaintiff seeking a judgment of inva-
lidity; rather, Seagate raised the defense of invalidity. See
TypeRight Keyboard Corp. v. Microsoft Corp., 374 F.3d
1151, 1156 (Fed. Cir. 2004); Therasense, 593 F.3d at 1337.
A cross-appeal is improper and warrants dismissal where,
as here, the cross-appellant “did not seek a declaratory
judgment of invalidity” and “assert[ed] invalidity only as
an affirmative defense to the claim of infringement.” An-
tennaSys, Inc. v. AQYR Techs., Inc., 976 F.3d 1374, 1377
n.1 (Fed. Cir. 2020). Accordingly, we dismiss Seagate’s
cross-appeal.
Although we dismiss Seagate’s cross-appeal, we may
consider the arguments made in the cross-appeal to the ex-
tent it affects our disposition of the main appeal. For in-
stance, we have previously held that where “an improper
cross-appeal is dismissed, we may nonetheless consider the
arguments raised in the improper cross-appeal as alterna-
tive grounds upon which we could affirm the judgment of
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the district court.” Praxair, Inc. v. ATMI, Inc., 543 F.3d
1306, 1322 (Fed. Cir. 2008). Accordingly, we next consider
Seagate’s arguments in its cross-appeal insofar as it affects
our disposition of the main appeal.5 We turn to one issue
raised in the cross-appeal: whether we should order a new
trial on invalidity.
B. New Trial on Enablement
Seagate argues that, if we “broaden[] the construction
of ‘uniaxial symmetry broken structure’” and order a new
trial on infringement, we should also order a new trial on
invalidity. Cross-Appellant’s Opening and Response
Br. 79–80. Seagate asserts that “LMS’s arguments for a
new trial on infringement are all intertwined with invalid-
ity.” Id. at 80. According to Seagate, a new trial on inva-
lidity would be necessary because LMS’s “arguments
against infringement are indistinguishably woven with the
factual underpinnings of validity.” Cross-Appellant’s Re-
ply Br. 18 (citation modified) (quoting Witco Chem. Corp. v.
Peachtree Doors, Inc., 787 F.2d 1545, 1549
(Fed. Cir. 1986)).
First, it is within our discretion to order a new trial on
enablement. The parties dispute whether, if we remand for
a new trial on infringement on the ground that the district
court misconstrued “uniaxial symmetry broken structure,”
we are required to also order a new trial on invalidity.
Cross-Appellant’s Opening and Response Br. 79–81; Appel-
lant’s Response and Reply Br. 63–64. We have generally
5 We note that, at oral argument, Seagate “drop[ped]
any rebuttal” as to whether the cross-appeal should be dis-
missed, “assume[d] that the cross-appeal has been dis-
missed,” and proceeded to address its “affirmative defense”
on enablement as “alternative grounds.” Oral
Arg. 28:30–55, available at https://oralarguments.cafc
.uscourts.gov/default.aspx?fl=23-1335_03042025.mp3.
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found that a party is entitled to a new trial on invalidity
under these circumstances, if the party shows that the dis-
trict court’s error was prejudicial. Witco, 787 F.2d at 1548;
Eaton Corp. v. Rockwell Int’l Corp., 323 F.3d 1332, 1344
(Fed. Cir. 2003). But regardless of a showing of prejudice,
we have the discretion to order a new trial on invalidity. In
Witco, for instance, we only provided that “[i]mproper con-
duct of the court that is prejudicial will warrant a new
trial.” 787 F.2d at 1548. We did not hold that it is a re-
quirement that, for us to order a new trial, such improper
conduct must be shown to be prejudicial. See id. Thus, we
have the discretion to order a new trial on enablement.
Second, we exercise our discretion to order a new trial
on enablement. The proper construction of “uniaxial sym-
metry broken structure” could change the arguments and
evidence necessary to show that the ’988 patent is not ena-
bled. We agree with Seagate that, under the “broader” con-
struction adopted herein, “the ’988 patent would need to
enable even more subject matter than was at issue in the
prior trial.” Cross-Appellant’s Opening and Response
Br. 80. Accordingly, we exercise our discretion to order a
new trial on enablement consistent with this opinion.6
CONCLUSION
We have considered the parties’ remaining arguments
and find them unpersuasive. For the foregoing reasons, we
dismiss the cross-appeal; vacate the district court’s
6 In light of our remand for a new trial on enable-
ment, we do not address Seagate’s assertion that a reason-
able jury could not have found the patent enabled, and in
particular, the parties’ corresponding arguments concern-
ing Amgen v. Sanofi, 598 U.S. 594, 610 (2023). Cross-Ap-
pellant’s Opening and Response Br. 71–79; Appellant’s
Response and Reply Br. 53–62. The parties are free to
raise these arguments in future proceedings below.
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judgment of noninfringement in favor of Seagate; and re-
mand for a new trial on infringement and enablement, un-
der the proper construction of “uniaxial symmetry broken
structure.”7
VACATED AND REMANDED AS TO THE MAIN
APPEAL; DISMISSED AS TO THE CROSS-APPEAL
COSTS
No costs.
7 LMS also argues that the district court made sev-
eral erroneous evidentiary rulings. Appellant’s Opening
Br. 42–70. Because we vacate the district court’s judgment
of noninfringement and order a new trial on infringement
and enablement, we need not reach these issues.
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