Stylwan Ip Holding, LLC, Stylwan, Inc., Stylwan Iit, LLC v. Stress Engineering Services, Inc.

N OTE: This disposition is nonprecedential.
United States Court of Appeals
for the Federal Circuit
______________________
STYLWAN IP HOLDING, LLC, STYLWAN, INC.,
STYLWAN IIT, LLC,
Plaintiffs-Appellants
v.
STRESS ENGINEERING SERVICES, INC.,
Defendant-Cross-Appellant
______________________
2023-1269, 2023-1271
______________________
Appeals from the United States District Court for the
Southern District of Texas in No. 4:20-cv-03297, Judge
Keith P. Ellison.
______________________
Decided: May 27, 2025
______________________
WILLIAM P ETERSON R AMEY , III, Ramey LLP, Houston,
TX, argued for plaintiffs-appellants.
CHRISTOPHER MC K EON, Saunders McKeon PLLC, Hou-
ston, TX, argued for defendant-cross-appellant. Also rep-
resented by G ORDON ARNOLD, J ASON S AUNDERS .
______________________
Before REYNA, T ARANTO, and CHEN, Circuit Judges.
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STYLWAN IP HOLDING, LLC v.
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REYNA, Circuit Judge.
Stylwan IP Holding, LLC, Stylwan, Inc., and Stylwan
IIT, LLC appeal from a final judgment of the United States
District Court for the Southern District of Texas. The dis-
trict court entered the judgment after the parties stipu-
lated to noninfringement of six asserted patents based on
the court’s claim constructions. For the reasons stated be-
low, we affirm.
BACKGROUND
I.
Stylwan IP Holding, LLC, Stylwan, Inc., and Stylwan
IIT, LLC (collectively, “Stylwan”) own U.S. Patent Nos.
7,231,320 (“’320 patent”); 7,403,871 (“’871 patent”);
8,050,874 (“’874 patent”); 8,086,425 (“’425 patent”);
8,428,910 (“’910 patent”); and 8,831,894 (“’894 patent”) (col-
lectively, the “Asserted Patents”).1 The Asserted Patents
relate to non-destructive systems and methods for as-
sessing material integrity, such as in pipelines and pres-
sure vessels commonly used in the oil and gas industry.
See, e.g., ’320 patent, 1:15–21, 1:51–58. This includes non-
destructive inspection (“NDI”), remaining useful life esti-
mation (“RULE”), and fitness for service (“FFS”) assess-
ment systems. In such industries, equipment material
may be selected “based on criteria including minimum
strength requirements, useable [sic] life, and anticipated
normal wear.” Id. at 1:25–41. But over time, a material
can weaken from mechanical or environmental stress,
leading to safety and operational concerns, among other is-
sues. Id. at 32–38.
1 The Asserted Patents are continuations-in-part of
a common patent application—U.S. Patent App. No.
10/995,692—and share related, though not identical, spec-
ifications.
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Non-destructive methods assess materials or equip-
ment without causing damage, unlike techniques that re-
quire cutting the material or other destructive actions. Id.;
see also id. at 1:59–63, 9:30–33. These methods employ
various non-destructive sensing mechanisms such as mag-
netism, sound, or radiation to detect cracks, corrosion, or
other material imperfections. Id. at 1:42–48, 2:29–33,
3:26–29. Prior art NDI techniques often rely on one-dimen-
sional signal processing to assess these imperfections—i.e.,
using one sensor per inspection area. Id. at 2:6–34. But
these prior art techniques frequently yield inaccurate re-
sults, in part, because they cannot effectively evaluate the
multidimensional nature of material defects.
Id. at 2:6–3:12. As a result, the identified defects typically
require costly and time-consuming manual verification.
Id. at 4:14–24.
The Asserted Patents sought to address the aforemen-
tioned problems by providing systems that use complex sig-
nal analysis and computational methods to accurately
detect material defects, assess structural integrity and fit-
ness-for-service, and estimate the remaining useful life of
an inspected material, without the need for manual verifi-
cations. See, e.g., id. at 6:57–7:24, 9:20–10:27. Claim 1 of
the ’874 patent is representative of a system for estimating
the remaining useful life of a material—i.e., one type of sys-
tem claimed in the Asserted Patents—and recites:
1. An evaluation system for materials comprising:
at least one computer;
a material features acquisition system operable to
receive signals indicative of a plurality of material
features while said material is not in operation;
utilizing a plurality of identifier equations and co-
efficients for analyzing said signals;
at least one database comprising at least one of con-
straints and material historical data;
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wherein said at least one computer is programmed
to utilize said plurality of identifier equations and
coefficients and said at least one database to esti-
mate a remaining useful life of a material under
evaluation.
’874 patent, claim 1 (43:56–44:2) (emphases added).
II.
On September 23, 2020, Stylwan sued Stress Engineer-
ing Services, Inc. (“SES”) in the United States District
Court for the Southern District of Texas. Two days later,
it filed an amended complaint alleging infringement of the
six Asserted Patents. In response, SES moved to dismiss
the amended complaint, arguing that the Asserted Patents
were directed to patent-ineligible subject matter under 35
U.S.C. § 101. The district court disagreed and found that
the Asserted Patents were not directed to patent-ineligible
subject matter. On February 22, 2022, the district court
issued a claim construction order, construing three catego-
ries of disputed terms referred to here as the “sensor/sig-
nal,” “excitation,” and “program” limitations.2 Stylwan IP
Holding, LLC, et al. v. Stress Eng’g Servs., Inc., No. 4:20-
2 We primarily reference the construed terms as cat-
egorized in Stylwan’s briefing. Accordingly, the sensor/sig-
nal limitations include the terms “imperfection detection
sensor,” “sensor(s),” “imperfection signal(s),” “signal(s),”
“producing an imperfection signal,” “receive signals,” “de-
tect a plurality of material features,” “operable to detect,”
and “detect.” Appellant Br. 9. The excitation limitations
include the terms “induction of an excitation” and “excita-
tion.” The program limitations include the terms “pro-
gram,” “programming,” “programmed,” “programmable,”
“processor,” and “material features acquisition system.”
Id.
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cv-3297 (S.D. Tex. Feb. 22, 2022) (“Markman Order”), at
J.A. 17–18.
On October 13, 2022, as a result of claim construction,
the parties jointly stipulated to a judgment of noninfringe-
ment of all Asserted Patents.3 J.A. 11–14. On June 28,
2023, the court entered a final judgment of noninfringe-
ment pursuant to the parties’ joint stipulation. J.A. 1–2.
The final judgment observed that the parties reserved their
rights to appeal the district court’s claim construction and
corresponding clarification orders. Id. SES separately re-
served its right to appeal the district court’s determination
of patent eligibility under 35 U.S.C. § 101. Id.
Stylwan timely appealed, and SES cross-appealed. We
have jurisdiction pursuant to 28 U.S.C. § 1295(a)(1).
D ISCUSSION
On appeal, Stylwan challenges the district court’s con-
structions of the sensor/signal, excitation, and program
limitations. Appellant Br. 2. We address only the program
limitations because, during oral argument, counsel for
Stylwan acknowledged that an affirmance of the district
court’s construction of the program limitations would re-
solve this case. Oral Arg. at 40:30–50.4 We agree, and
since we affirm the district court’s construction of the pro-
gram limitations, we do not reach the remaining issues
raised on appeal, including the district court’s construction
of the sensor/signal and excitation limitations. See Inpro
3 The following claims of the Asserted Patents are at
issue on appeal: ’320 patent (claims 1 and 14), ’871 patent
(claim 1), ’874 patent (claims 1, 7–8, 21–25, 30, 31, 36, 43,
and 47), ’425 patent (claims 1, 7, 20, 22, 28, 29, 37, 44, 46,
47, and 55), ’910 patent (claims 24, 29–34), and ’894 patent
(claims 1, 4–6) (collectively, the “Asserted Claims”).
4 Available at https://oralarguments.cafc.uscourts.
gov/default.aspx?fl=23-1269_12062024.mp3.
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II Licensing, S.A.R.L. v. T-Mobile USA, Inc., 450 F.3d 1350,
1352 (Fed. Cir. 2006).
SES cross-appeals the district court’s judgment of pa-
tent eligibility under 35 U.S.C. § 101. Appellee Br. 1. SES
confirmed at oral argument that the § 101 challenge was
raised solely as an alternative ground for affirmance. Oral
Arg. at 41:32–42:20. Because SES seeks to uphold—not
modify—the district court’s § 101 judgment, we treat this
argument as an alternative ground for affirmance rather
than a proper cross-appeal. Chiron Corp. v. Genentech,
Inc., 363 F.3d 1247, 1252 (Fed. Cir. 2004); see also Bailey v.
Dart Container Corp. of Michigan, 292 F.3d 1360, 1362
(Fed. Cir. 2002) (noting “a party must file a cross-appeal
when acceptance of the argument it wishes to advance
would result in a reversal or modification of the judgment
rather than an affirmance”). As we affirm on other
grounds, we do not reach SES’s alternative § 101 argu-
ment.
We now turn to the district court’s construction of the
program limitations.
I.
The district court construed the program limitations—
“program,” “programming,” “programmed,” “programma-
ble,” “processor,” and “material features acquisition sys-
tem”—to mean:
[C]omputer program that autonomously recognizes
the nature of the material features using three
identifier equations
𝑌𝑌𝑌𝑌 𝑖𝑖𝑖𝑖 = 𝑀𝑀 ∑ 𝑌𝑌𝑖𝑖𝑖𝑖 𝑋𝑋𝑎𝑎𝑘𝑘𝑘𝑘
𝑁𝑁
𝑖𝑖=1
𝑌𝑌𝑌𝑌 𝑖𝑖𝑖𝑖 = 𝑇𝑇(𝑀𝑀 ∑ 𝑎𝑎𝑖𝑖𝑘𝑘𝑋𝑋𝑎𝑎𝑘𝑘𝑘𝑘) 𝑁𝑁
𝑘𝑘=1
𝑌𝑌𝑌𝑌 𝑖𝑖𝑖𝑖 = 𝑀𝑀[1 + 𝑒𝑒 − ∑ 𝑎𝑎𝑖𝑖𝑘𝑘𝑋𝑋𝑎𝑎𝑘𝑘𝑘𝑘
𝑁𝑁
𝑘𝑘=1 ]−1
and autonomously distinguishes between defective
and non-defective material features.
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Markman Order, at J.A. 17–18. Stylwan argues the dis-
trict court erred by incorporating in its claim construction
two features taken from embodiments in the Asserted Pa-
tents—namely, the “autonomous[]” functionality and the
“three identifier equations.” Id.; see Appellant Br. 2. We
disagree.
“Claim construction requires determining how a skilled
artisan would understand a claim term ‘in the context of
the entire patent, including the specification.’” Grace In-
strument Indus., LLC v. Chandler Instruments Co., 57
F.4th 1001, 1008 (Fed. Cir. 2023) (quoting Phillips v. AWH
Corp., 415 F.3d 1303, 1313 (Fed. Cir. 2005) (en banc)). “Re-
garding questions of claim construction, [] the district
court’s determinations based on evidence intrinsic to the
patent as well as its ultimate interpretations of the patent
claims are legal questions that we review de novo.” Wil-
liamson v. Citrix Online, LLC, 792 F.3d 1339, 1346
(Fed. Cir. 2015). If the district court makes underlying
findings of fact based on extrinsic evidence, we review such
findings for clear error. Id. Under the clear-error stand-
ard, we defer to the district court’s findings “in the absence
of a definite and firm conviction that a mistake has been
made.” Par Pharm., Inc. v. Eagle Pharms., Inc., 44 F.4th
1379, 1383 (Fed. Cir. 2022) (citation omitted).
A.
Stylwan argues that the district court erred by constru-
ing the program limitations to require autonomous func-
tionality. Appellant Br. 31. We disagree and conclude that
the district court correctly construed the program limita-
tions as requiring autonomous functionality.
The intrinsic record supports autonomous functional-
ity. First, the Asserted Patents repeatedly characterize the
claimed inventions as “autonomous.” VirnetX, Inc. v. Cisco
Sys., Inc., 767 F.3d 1308, 1318 (Fed. Cir. 2014) (citation
omitted) (“The fact that [a feature] is ‘repeatedly and con-
sistently’ used to characterize the invention strongly
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suggests that it should be read as part of the claim.”). Here,
four of the Asserted Patents characterize the invention as
“autonomous” in the title of the patent, and the remaining
two do so in the first sentence of the abstract. See, e.g., ’320
patent, Abstract; ’874 patent, Title. The patents further
describe the inventions as “[a]utonomous non-destructive
inspection equipment,” “[a]utonomous remaining useful
life estimation equipment,” and “[a]utonomous fitness for
continuing service assessment equipment.” See, e.g., ’320
patent, Abstract; ’874 patent, Abstract; ’425 patent, Ab-
stract.
Further, autonomous functionality aligns with the lan-
guage of the independent claims. That is, the claim con-
struction confines the program limitations to
autonomously performing two core functions: recognizing
material features and distinguishing between defective
and non-defective features. See Markman Order,
J.A. 17–18. Consistent with this construction, claim 1 of
the ’425 patent recites, for example, “at least one program
being executed on said at least one computer to utilize said
material features recognition equations for identifying said
plurality of material features.” ’425 patent, claim 1. Claim
1 of the ’874 patent recites that “at least one computer is
programmed to utilize said plurality of identifier equations
and coefficients and said at least one database to estimate
a remaining useful life of a material under evaluation.”
’874 patent, claim 1. These provisions make clear that the
relevant analysis is executed autonomously by a computer
without human intervention.
The patent specifications define “autonomous” as “able
to function without external control or intervention.” See,
e.g., ’320 patent, 5:48–49. The specifications describe the
claimed inventions as using computer programs to repli-
cate pattern recognition and inspection tasks traditionally
performed by human inspectors. See, e.g., id. at 10:7–24.
The Asserted Patents expressly criticize manual processes,
warning that “uncontrollable ‘human factors’” and human
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decisions “may lead to a catastrophic failure.” See, e.g., ’874
patent, 11:38–40, 12:9–12.
The prosecution history also reinforces that the inven-
tors limited their claims to autonomous systems. Express
statements made during prosecution to distinguish the
claimed invention from prior art may also narrow the scope
of the claim. Purdue Pharma L.P. v. Endo Pharms.
Inc., 438 F.3d 1123, 1136 (Fed. Cir. 2006). For example,
during prosecution of the application for the ’425 patent,
the applicants amended their claims to require that a com-
puter program make the fitness for service determination
in order to reduce human intervention error. J.A. 2267.
The applicants argued that the cited prior art, where hu-
man inspections are required to determine whether a ma-
terial is fit for service, “does not apply [where] the
computer is programmed to determine whether or not the
material should be removed from service.” Id.
In sum, because the intrinsic record shows that the
claimed inventions autonomously perform the core func-
tions of recognizing material features and distinguishing
between defective and non-defective features, we conclude
that the district court properly construed the program lim-
itations to require autonomous functionality.
B.
Stylwan argues that the district court erred by incor-
porating the disclosed identifier equations into its con-
struction of the program limitations, asserting that these
equations are unnecessary for the invention to function be-
cause the invention can function using other mathematical
formulas as well. Appellant Br. 37–38. We disagree.
First, the patents expressly state that “[t]he fundamen-
tal operation of the autonomous NDI is performed by the
identifier equations.” See, e.g., ’320 patent, 10:38–41 (em-
phasis added). The “identifier equations” that are de-
scribed in the patents are the three equations that the
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district court incorporated in its claim construction. Com-
pare id. at 11:10–36, with Markman Order, J.A. 18. The
patents further explain that “[i]t should be understood that
each stage may comprise multiple identifier equations uti-
lizing equations 1, 2, or 3.” ’320 patent, 11:37–38. This is
consistent with the claim construction’s limitation that the
autonomous detection of material features depends on us-
ing the three disclosed equations. See Markman Order,
J.A. 17–18.
Second, the district court’s construction is proper be-
cause, as SES highlights, the identifier equations satisfy
the enablement requirement under 35 U.S.C. § 112. See,
e.g., ’320 patent, 10:24–27 (“The detailed mathematical
procedures are described hereinbelow and enable one
skilled in the art to implement the autonomous NDI de-
scribed herein without undue experimentation.”); see also
Appellee Br. 13. Stylwan does not dispute this assertion.
Appellant Br. 38 (noting the identifier equations “were pro-
vided only to assist one of ordinary skill in the art with en-
ablement”).
It is well established by our precedent that the scope of
the claims must align with the scope of the enablement.
MagSil Corp. v. Hitachi Glob. Storage Techs., Inc., 687
F.3d 1377, 1380–81 (Fed. Cir. 2012). As we have explained:
Enablement serves the dual function in the patent
system of ensuring adequate disclosure of the
claimed invention and of preventing claims broader
than the disclosed invention. This important doc-
trine prevents both inadequate disclosure of an in-
vention and overbroad claiming that might
otherwise attempt to cover more than was actually
invented. . . . The scope of the claims must be less
than or equal to the scope of the enablement to en-
sure that the public knowledge is enriched by the
patent specification to a degree at least commensu-
rate with the scope of the claims.
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Id. (cleaned up). Notably, although Stylwan argues the
claimed inventions could operate with other mathematical
formulas, it does not assert—nor do we find—that the in-
ventors enabled the use of any formulas beyond the three
disclosed identifier equations. Thus, even assuming the
claimed inventions could operate using other formulas, the
district court did not err by limiting the claims to the iden-
tifier equations in its construction.
CONCLUSION
We have considered the parties’ remaining arguments
and find them unpersuasive. Based on the reasons stated
above, we hold that the district court’s claim construction
of the program limitation terms is supported by the intrin-
sic evidence and, as such, the claim construction was not
erroneous. We hereby affirm the district court’s final judg-
ment of noninfringement of the Asserted Patents.
AFFIRMED
COSTS
Costs against Stylwan.
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