Cases2tech, LLC v. John A. Squires, Under Secretary of Commerce for Intellectual Property

N OTE: This disposition is nonprecedential.
United States Court of Appeals
for the Federal Circuit
______________________
CASES2TECH, LLC,
Appellant
v.
JOHN A. SQUIRES, UNDER SECRETARY OF
COMMERCE FOR INTELLECTUAL PROPERTY
AND DIRECTOR OF THE UNITED STATES
PATENT AND TRADEMARK OFFICE,
Intervenor
______________________
2023-2290
______________________
Appeal from the United States Patent and Trademark
Office, Patent Trial and Appeal Board in No. IPR2022-
00282.
______________________
Decided: November 4, 2025
______________________
T IMOTHY D EVLIN, Devlin Law Firm LLC, Wilmington,
DE, for appellant. Also represented by ANDREW P ETER
D EMARCO, R OBERT J. G AJARSA , J ASON M ITCHELL SHAPIRO.
MAI-T RANG D UC D ANG, Office of the Solicitor, United
States Patent and Trademark Office, Alexandria, VA, for
intervenor. Also represented by O MAR F AROOQ AMIN,
P ETER J. AYERS , AMY J. N ELSON.
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CASES2TECH , LLC v. SQUIRES 2
______________________
Before T ARANTO, SCHALL , and STARK, Circuit Judges.
T ARANTO, Circuit Judge.
In late 2021, Samsung Electronics Co. and an affiliate
(collectively, Samsung) petitioned the Patent and Trade-
mark Office (PTO) for institution of an inter partes review
(IPR) of all twenty claims of U.S. Patent No. 8,315,400,
then owned by Staton Techiya, LLC, and now assigned to
the current appellant, Cases2Tech, LLC (collectively, Tech-
iya). The ’400 patent describes and claims noise-suppress-
ing earpieces and methods for using them. The IPR was
instituted, and the PTO’s Patent Trial and Appeal Board
(Board) eventually held seven claims unpatentable for an-
ticipation and another eight for obviousness. Samsung
Electronics Co. v. Staton Techiya, LLC, IPR2022-00282
(P.T.A.B. June 14, 2023).
On appeal, Techiya offers two claim-construction chal-
lenges to the Board’s decision, each pertinent to all claims
held unpatentable. First, Techiya argues that the Board’s
express claim construction of the claim term “background
noise level” was incorrect. Second, Techiya argues that the
Board implicitly, and incorrectly, broadened the phrase
“based on” beyond its ordinary meaning in the claim phrase
“adjust a[ ] . . . sound signal based on the background noise
level.” We reject both challenges and affirm.
I
A
The ’400 patent is titled “Method and Device for Acous-
tic Management Control of Multiple Microphones,” J.A. 97,
and has twenty claims, of which claims 1, 14, and 18 are
independent. The patent describes and claims an earpiece
(along with methods for using it) that is capable of sup-
pressing background noise by mixing, through a “proces-
sor,” the signals from two microphones mounted on the
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CASES2TECH , LLC v. SQUIRES 3
earpiece. ’400 patent, col. 2, lines 16–40; see also id., col. 1,
lines 17–25; col. 6, lines 41–57. One microphone, the “ear
canal microphone,” is mounted close to the speaker of the
earpiece and faces inward toward the eardrum, such that,
when the earpiece is worn, the seal created between the
user’s ear canal and the earpiece partially muffles the
sound received by that microphone. See id., col. 4, lines 27–
50. A second, “ambient sound” microphone, mounted on
the outside of the device, captures environmental noise
(such as traffic sounds, nearby conversations, and the like).
See id., col. 5, lines 41–48; col. 7, lines 19–26.
The ’400 patent describes how the signals received by
the two microphones can be mixed to reduce “background
noise,” thereby “enhanc[ing] intelligibility” of the resulting
noise-reduced signal, which is played for the user through
the earpiece’s speaker. Id., col. 6, line 41 through col. 7,
line 7; see also fig. 3 (illustrating the same). In certain em-
bodiments, this mixing is based on a background noise level
(i.e., a sound pressure, measured in decibels). E.g., id., col.
3, line 53 through col. 4, line 6. In others, the two micro-
phone signals are mixed using a background noise signal,
which is a more expansive concept—a background noise
level is one part of a background noise signal. Id., col. 1,
lines 64–67; col. 6, lines 64–66; see J.A. 61 (Board noting
that parties agreed on this relationship between the level
and signal terms).
“Background noise level” and “background noise sig-
nal” are not expressly defined. The patent discloses, how-
ever, that a background noise level can be an average
“weighted using a frequency-weighting system . . . [for ex-
ample, by attenuating] the high and low frequencies . . . .”
Id., col. 3, lines 59–64. A background noise level can be
continuously evaluated and used to determine an appropri-
ate mix between the microphone signals: “At low back-
ground noise levels,” the earpiece’s processor can amplify
the signal from the ambient sound microphone, whereas at
“medium” and “high background noise levels,” the
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CASES2TECH , LLC v. SQUIRES 4
processor progressively increases the contribution of the
ear canal microphone signal to the mix, especially the rel-
atively low frequencies of that signal. See id., col. 7, lines
27–41; fig. 10. And “based on the characteristics of the
background noise” the processor can apply “frequency spe-
cific filters” to the microphone signals. Id., col. 7, lines 38–
41.
Techiya has consistently maintained that background
noise “level” and “signal,” although the former is an attrib-
ute of the latter, are not meaningfully different for the pur-
poses of its present claim-construction arguments about
those terms, so independent claim 1, which uses “level,” is
representative even though the other two independent
claims (14 and 18) use “signal.” See J.A. 22–23; Techiya’s
Opening Br. at 6–7, 26. Independent claim 1 states:
1. An earpiece comprising:
at least one Ambient Sound Microphone (ASM)
configured to convert ambient sound to an ambient
sound signal;
at least one Ear Canal Microphone (ECM) config-
ured to convert an internal sound from an ear canal
of a user to an internal sound signal and where the
internal sound signal includes an internal voice of
the user; and
a processor operatively coupled to the at least one
ASM and the at least one ECM and which receives
the ambient sound signal and the internal sound
signal, and where the processor is configured to:
determine a background noise level from at
least one of the ambient sound signal or the inter-
nal sound signal, and to adjust an amplitude of
one or more frequencies of the internal sound
signal and the ambient sound signal based on
the background noise level, to filter the internal
sound signal relative to the ambient sound signal.
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CASES2TECH , LLC v. SQUIRES 5
Id., col. 12, lines 21–38 (emphases added to show disputed
terms); see J.A. 114 (certificate of correction). Claim 5,
which depends on claim 1 through claims 4, 3, and 2, is im-
portant to Techiya’s arguments. It states:
5. The earpiece of claim 4 where at low background
noise levels the ambient sound signal from the
ASM is amplified relative to the internal sound sig-
nal from the ECM, where at medium background
noise levels low frequencies of the ambient sound
signal are attenuated and high frequencies of the
internal sound signal are attenuated, and where at
high background noise levels the internal sound
signal from the ECM is amplified relative to the
ambient sound signal from the ASM.
’400 patent, col. 12, lines 51–59.
B
In November 2021, Techiya sued Samsung in district
court for infringement of the ’400 patent, among others.
Amended Complaint at 1–2, ¶¶ 1, 9, Staton Techiya, LLC
v. Samsung Electronics Co., No. 2:21-cv-00413 (E.D. Tex.
Nov. 12, 2021), ECF No. 11. The following month, Sam-
sung petitioned the PTO for institution of an IPR of the ’400
patent, challenging all twenty claims. See J.A. 8, 119; 35
U.S.C. §§ 311–19. Samsung alleged, as relevant here, that
claims 1, 6–8, 12–15, and 17 were anticipated by U.S. Pa-
tent Application Publication No. 2008/0037801 (Alves) and
that claims 2–5, 9–11, 16, and 18–20 were unpatentable for
obviousness over Alves in view of certain other prior art
references. J.A. 8.
Alves is titled “Dual Microphone Noise Reduction for
Headset Application.” J.A. 586. Like the ’400 patent, Alves
describes an earpiece with a signal processing system, a
speaker, and two microphones, one in the ear canal and one
outside. J.A. 587, fig. 1; 601 ¶ 15. The Alves system re-
duces noise in the signal from the external microphone by,
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CASES2TECH , LLC v. SQUIRES 6
first, dividing the signal into “subbands,” each subband
containing only certain frequencies; second, within each
subband, computing the average power of background
noise; and, finally, filtering that background noise out of
each subband to then recombine the modified subbands for
further processing. J.A. 603–04 ¶¶ 42–43, 47. Afterward,
the noise-reduced external microphone signal is mixed
with the internal microphone signal to generate the
speaker output heard by the wearer. J.A. 588, fig. 3.
The Board, acting for the PTO’s Director, instituted an
IPR in June 2022, J.A. 948, and rendered its final written
decision in June 2023, J.A. 1. In an analysis of Alves not
challenged here, see Techiya’s Opening Br. at 30–37, the
Board found that Alves’s noise reduction system has sev-
eral components that perform different parts of its signal
processing method, see J.A. 27–29, 35–44. One is a “noise
reducer,” which receives a signal from the external micro-
phone and “eliminates some noise” from that signal. J.A.
602 ¶ 31. Another is an “adaptive equalizer,” which “ad-
justs the output of [the] second[, i.e., internal] microphone
to the spectral characteristics of” the external microphone
signal. Id. ¶ 32. The noise-reduced external signal (not the
unmodified, noisy external signal) is used by Alves’s sys-
tem to “set filter coefficients,” which are applied by the
adaptive equalizer to the internal signal to filter it with re-
spect to the noise-reduced external signal. Id. ¶¶ 31–32.
Two other Board determinations are relevant on ap-
peal. First, in its claim-construction analysis, the Board,
relying on both intrinsic evidence and Samsung’s expert
testimony, construed the claim term “background noise
level” to include “any one frequency subband’s particular
background noise level.” J.A. 11–18. Applying that claim
construction, the Board found that Alves discloses deter-
mining a background noise level as claimed by the ’400 pa-
tent, J.A. 32–34, 61, 88–89, which was necessary to all of
its determinations of unpatentability because such a limi-
tation appears in all independent claims. See ’400 patent,
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CASES2TECH , LLC v. SQUIRES 7
col. 12, lines 21–38 (claim 1); col. 13, lines 20–36 (claim 14);
col. 14, lines 9–32 (claim 18).
Second, the Board found that Alves discloses the ’400
patent’s claimed adjustment of amplitudes of an internal
sound signal “based on” a background noise level. Techiya
had argued that, because Alves’s adaptive equalizer re-
ceives a noise-reduced ambient signal from Alves’s noise
reducer, the adaptive equalizer’s use of the noise-reduced
ambient signal to adjust the internal signal is not “based
on” the background noise level, which has already been
stripped out. J.A. 35–36. The Board disagreed, determin-
ing that the Alves system’s adjustments of an internal sig-
nal (in particular, through “the combination of [the] noise
reducer [ ] and [the] adaptive equalizer”) are based on a
background noise level because the noise-reduced ambient
signal is used as a “control input” to the adaptive equalizer,
against which the internal signal is adjusted and filtered.
J.A. 38–39.
The Board held claims 1, 6–7, 12–14, and 17 unpatent-
able for anticipation by Alves and claims 2–3, 9–11, and
18–20 unpatentable for obviousness over a combination of
Alves and another reference. J.A. 2, 94. It further held
that Samsung had failed to show the unpatentability of the
remaining claims (4–5, 8, and 15–16). Id.
Techiya timely appealed on August 11, 2023, ECF
No. 1, and Samsung cross-appealed the same day, see ECF
No. 3; J.A. 119. The parties later jointly stipulated to dis-
missal of the cross-appeal, Samsung filed a notice of non-
participation, and we dismissed the cross-appeal. ECF
Nos. 40–41, 43. Shortly afterward, the Director timely in-
tervened as of right to defend the Board’s decision under
35 U.S.C § 143. ECF No. 44. We have jurisdiction under
35 U.S.C. §§ 141(c), 319 and 28 U.S.C. § 1295(a)(4)(A).
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CASES2TECH , LLC v. SQUIRES 8
II
On appeal, Techiya asserts two grounds of error, each
related to claim construction and each relevant to all
claims held unpatentable. We review the Board’s claim
constructions and its analysis of the intrinsic record with-
out deference. Intel Corp. v. Qualcomm Inc., 21 F.4th 801,
808 (Fed. Cir. 2021). Subsidiary factfinding based on ex-
trinsic evidence is reviewed for substantial evidentiary
support. Id. Substantial evidence is “such relevant evi-
dence as a reasonable mind might accept as adequate to
support a conclusion.” Consolidated Edison Co. v. National
Labor Relations Board, 305 U.S. 197, 229 (1938). We reject
Techiya’s challenges.
A
Techiya’s first contention is that the Board erred when
it expressly construed the claimed “background noise level”
to encompass a background noise level in a subset of sound
frequencies, like the noise within one of Alves’s subbands,
rather than, as Techiya urges, to be limited to a “single
overall background noise level.” Techiya’s Opening Br. at
19–30. Techiya makes no different arguments for the re-
lated term “background noise signal,” which appears in a
similar context in independent claims 14 and 18, see id. at
26, so we treat the two terms together.
Techiya relies heavily on dependent claim 5, which re-
cites “low,” “medium,” and “high background noise levels.”
Techiya argues that those characterizations often could not
be sensibly applied to background noise in multiple sub-
bands, because the noise could be low in one subband but
high in another, so claim 5 must refer only to one overall
background noise and, says Techiya, the same must be true
of claim 1 because it is presumptively broader. Techiya’s
Opening Br. at 25. Techiya makes a similar point about a
disclosure in the specification that teaches adjusting the
ambient and internal sound signals based on whether the
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CASES2TECH , LLC v. SQUIRES 9
“background noise levels increase” or “decrease.” ’400 pa-
tent, col. 1, lines 56–62; see Techiya Opening Br. at 22.
When construing claims, the “[c]laim language and the
specification . . . are the dominant sources of interpreta-
tion.” Intel, 21 F.4th at 809. The language of dependent
claims can inform the scope of terms used in the corre-
sponding independent claims because “[d]ependent claims
are presumed to be of narrower scope than the [correspond-
ing] independent claims,” such that a claim construction
that would result in a dependent claim being broader than
its independent claim is disfavored. AK Steel Corp. v. Sol-
lac and Ugine, 344 F.3d 1234, 1242 (Fed. Cir. 2003); see
also 35 U.S.C. § 112 ¶ 4 (2006). Here, we conclude, the
claims and the specification do not support Techiya’s claim
construction.
The language of “background noise level” is broad
enough on its face to cover both an overall level and a level
of part of the signal. No words provide for Techiya’s pro-
posed narrowing to the first meaning. And the specifica-
tion points against Techiya’s proposal. It states, twice, that
the internal and ambient sound signals can be adjusted “by
the spectral profile of the background noise measurement.
For instance, if there is a large Low Frequency noise in the
ambient sound field of the user, then the [ambient sound
microphone] filter can [adjust] the low-frequencies” of each
of the ambient and internal sound signal. ’400 patent, col.
4, lines 6–13; id., col. 11, lines 27–33. That is, a “high” (or
“large”) background noise level can properly refer to a por-
tion of the entire noise spectrum (in the example just given,
the low frequencies), and in such a case the patent provides
guidance for adjusting the amplitude of the corresponding
frequencies of the ambient and internal signals. Similarly,
the patent’s disclosure of “a frequency-weighting system”
whereby “the high and low frequencies [of the background
noise level] are attenuated before the level of the micro-
phone signals are calculated,” directs readers to focus on
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CASES2TECH , LLC v. SQUIRES 10
only a portion of the entire audio frequency spectrum
(there, the middle frequencies). Id., col. 3, lines 59–64.
Claim 5 does not support Techiya’s proposal either.
Even under Techiya’s characterization of claim 5 as limited
to an overall background noise level, claim 5 would be nar-
rower, not broader, than claim 1, which under the Board’s
view encompasses both overall and subband levels. Tech-
iya’s premise that the independent claim must be broader
than the dependent claim thus does not support its position
that claim 1 cannot include coverage of subband levels.
That is enough to support the Board’s claim construction,
even apart from the Board’s conclusion—itself not shown
to be incorrect—that claim 5 itself “can refer to background
noise levels within multiple frequency subbands.” J.A. 15.
Techiya repeatedly cites expert testimony that “at any
given place and time, a single ‘background noise’ exists.”
J.A. 1111 ¶ 64; see, e.g., Techiya’s Opening Br. at 20. Even
if that is so, it does not establish that only a single back-
ground noise exists, and if that is what Techiya is suggest-
ing, the Board was not obligated to credit the cited
testimony to so find. See Apple Inc. v. Corephotonics, Ltd.,
81 F.4th 1353, 1360–61 (Fed. Cir. 2023). That is especially
so because the ’400 patent refers to “background noises
[that] can degrade the quality of the listening experience,”
’400 patent, col. 1, lines 32–34 (emphasis added), and dis-
cusses “background noise levels,” e.g., id., col. 10, lines 1,
65 (emphasis added). To be sure, there are some embodi-
ments that suggest the calculation of a single, overall back-
ground noise level. See, e.g., col. 6, lines 41–57 (pertaining
to figure 3) (“[M]ixing . . . depend[s] on the background
noise level of the ambient sound field.”). But no such em-
bodiment is expressly limiting, and we see no clear intent
to limit the claims to such embodiments. See col. 3, lines
17–20 (expressly stating that embodiments are non-limit-
ing); Innova/Pure Water, Inc. v. Safari Water Filtration
Systems, Inc., 381 F.3d 1111, 1117 (Fed. Cir. 2004). There-
fore, Techiya has failed to demonstrate that the Board
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CASES2TECH , LLC v. SQUIRES 11
erred in construing “background noise level” to include the
background noise level within a portion, or subband, of the
sound spectrum.
B
Techiya’s second argument is that the Board, in ana-
lyzing whether Alves discloses the claimed “adjust[ing] an
amplitude of one or more frequencies of the internal sound
signal . . . based on the background noise” level, errone-
ously expanded the scope of the term “based on” beyond its
ordinary meaning to include adjustments “made independ-
ent of the background noise.” Techiya’s Opening Br. at 30
(quoting ’400 patent, col. 12, lines 34–37) (emphases Tech-
iya’s). We see no persuasive basis in this argument for dis-
turbing the Board’s decision.
The Board’s pertinent findings and logic can be sum-
marized as follows: The ’400 patent’s claimed “processor”
reads on Alves’s system, which includes Alves’s noise re-
ducer and adaptive equalizer as components. See J.A. 32.
The noise reducer receives an ambient sound signal with a
background noise level and, “based on” that level, reduces
or eliminates noise in the ambient sound signal. J.A. 38,
40. The adaptive equalizer receives the noise-reduced am-
bient signal and uses it to adjust a second signal from
Alves’s internal microphone. Id. The noise-reduced ambi-
ent signal is a “control input” for determining how the in-
ternal signal should be filtered; if the background noise
were not first removed from the ambient signal, the inter-
nal signal would be adjusted differently. See J.A. 38–39.
Thus, Alves’s system (the claimed processor), by the com-
bination of the operation of the noise reducer and the adap-
tive equalizer, performs the claimed “adjust[ment]” of the
“internal sound signal . . . based on the background noise
level,” because the initial removal of background noise af-
fects how the internal sound signal is adjusted. See J.A.
35–40.
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CASES2TECH , LLC v. SQUIRES 12
Techiya argues that the foregoing facts cannot support
a determination that Alves discloses adjusting an internal
signal “based on” a background noise level because “the
background noise level is not known by [Alves’s] adaptive
equalizer.” J.A. 1040 (Techiya patent owner response) (em-
phasis added); Techiya’s Opening Br. 31, 34 (making simi-
lar assertions). But the Board found, and Techiya does not
dispute, that the ’400 patent’s claimed processor (which is
the element that determines a background noise level and
adjusts an internal signal based on that level) encompasses
both Alves’s noise-reducer and adaptive equalizer. J.A. 32;
see Techiya’s Opening Br. at 30–37 (not challenging
Board’s findings of fact). Thus, Techiya’s position appears
to be that, for the claimed processor to adjust an internal
sound signal “based on” the background noise level, the
same component of the processor (such as the adaptive
equalizer) must both receive the background noise and per-
form the adjustment. See, e.g., Techiya’s Opening Br. at
31; Techiya’s Reply Br. at 24 (asserting that “a component
. . . must . . . have the background noise level as a[n] . . .
input”).
We agree with the Board that Techiya advances a be-
lated, and incorrect, narrowing construction. See J.A. 39.
Techiya did not squarely ask the Board to construe the
“based on” claim language according to Techiya’s narrow,
same-component understanding, see J.A. 11–26; 1035–42
(Techiya’s patent owner response), so that argument was
forfeited, see In re Google Technology Holdings LLC, 980
F.3d 858, 863 (Fed. Cir. 2020). Furthermore, the intrinsic
record is contrary to Techiya’s construction. The ’400 pa-
tent discloses a singular “processor,” comprising multiple
components, that performs various functions. See, e.g.,
’400 patent, figs. 4–6 (depicting processor components). In
view of that disclosure, the claimed processor configured to
(1) determine a background noise level from a received am-
bient sound signal and (2) adjust an internal sound “based
on” that level must perform both of those steps, but there
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is no requirement that a single component within the pro-
cessor do so. Cf. Salazar v. AT&T Mobility LLC, 64 F.4th
1311, 1316–17 (Fed. Cir. 2023) (discussing claims to a pro-
cessor “defined by certain recited characteristics” which
therefore “require[d] a single processor having all [those]
characteristics”) (cleaned up) (emphasis added).
Techiya cites no intrinsic evidence and no case law in
support of its contrary reading of the “based on” limitation.
See Techiya’s Opening Br. at 30–37; Techiya’s Reply Br. at
21–25. Instead, Techiya refers extensively to Alves and ex-
pert testimony about Alves. See Techiya’s Opening Br. at
30–37; Techiya’s Reply Br. at 21–25. Alves, not cited by
the ’400 patent, is of minimal relevance to the interpreta-
tion of the ’400 patent. See Finisar Corp. v. DirecTV Group,
Inc., 523 F.3d 1323, 1328 (Fed. Cir 2008) (“[E]xtrinsic
sources . . . cannot overcome more persuasive intrinsic evi-
dence.”). Techiya identifies nothing in Alves pertinent to
the question whether a relevant artisan would understand
that the ’400 patent’s processor adjusts a signal “based on”
background noise only when a single component both re-
ceives background noise and adjusts a signal.
We have considered Techiya’s remaining arguments
and are not persuaded that they support its challenge to
the Board’s ruling.
III
For the foregoing reasons, we affirm the decision of the
Board.
AFFIRMED
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