Intellectual Pixels Limited v. Sony Interactive Entertainment LLC

United States Court of Appeals
for the Federal Circuit
______________________
INTELLECTUAL PIXELS LIMITED,
Appellant
v.
SONY INTERACTIVE ENTERTAINMENT LLC,
Appellee
______________________
2024-2174
______________________
Appeal from the United States Patent and Trademark
Office, Patent Trial and Appeal Board in No. IPR2021-
00237.
______________________
Decided: July 10, 2026
______________________
D OUGLAS R. WILSON, Armond Wilson LLP, Austin, TX,
argued for appellant. Also represented by MICHELLE
ARMOND, J OSEPHER L I , Newport Beach, CA.
J AMES MURPHY DOWD, Wilmer Cutler Pickering Hale
and Dorr LLP, Los Angeles, CA, argued for appellee. Also
represented by T HOMAS SAUNDERS , Washington, DC;
SHARCHUN D ENNIS W ANG, Palo Alto, CA.
______________________
Before D YK, STOLL , and STARK, Circuit Judges.
Case: 24-2174 Document: 41 Page: 1 Filed: 07/10/2026

-- 1 of 13 --

INTELLECTUAL PIXELS LIMITED v.
SONY INTERACTIVE ENTERTAINMENT LLC
2
D YK, Circuit Judge.
Intellectual Pixels Limited (“IPL”) appeals a decision of
the Patent Trial and Appeal Board (the “Board”) holding
claims 1–12 of U.S. Patent No. 10,681,109 (the “’109 pa-
tent”) unpatentable as obvious. This decision followed a
remand from our court of a Board decision holding the
claims not unpatentable. Because the Board did not violate
our prior mandate, and its decision was supported by sub-
stantial evidence, we affirm.
BACKGROUND
I
The ’109 patent discloses methods for generating digi-
tal images using an external visual server and systems im-
plementing the disclosed method. Image generation is a
resource-intensive process for computers and, at the prior-
ity date of the ’109 patent, many standard user-operated
devices struggled to render complex images on their own.
To address this, “[s]everal existing systems utilize[d] the
client-server model,” whereby the user-operated client de-
vice outsourced aspects of the image processing to separate
external servers. ’109 patent, col. 1 ll. 55–57. The image
data transmitted from the external server to the client de-
vice was compressed, allowing for “a high level-of-detail,
high quality image that require[d] relatively low transmis-
sion bandwidth.” Id. col. 2 ll. 15–19. Outsourcing some of
the data processing and compressing the transmitted im-
ages “decrease[d] the computational load of the client and
reduce[d] communication costs.” Id. col. 2 ll. 19–23.
The ’109 patent’s purported advance over this prior art
is said to be using the external server to handle all of the
visual processing, such that the client device merely re-
ceives user input, transmits that input information to the
external server, receives a compressed image from the ex-
ternal server in response, and decompresses it so that it
can be displayed to the user. Id. col. 3 ll. 41–57. In the
Case: 24-2174 Document: 41 Page: 2 Filed: 07/10/2026

-- 2 of 13 --

INTELLECTUAL PIXELS LIMITED v.
SONY INTERACTIVE ENTERTAINMENT LLC
3
claimed invention, the external server is fully responsible
for generating the new image, taking that burden com-
pletely off of the client device. See id.
Sony Interactive Entertainment LLC (“Sony”) peti-
tioned for inter partes review of claims 1–121 of the ’109 pa-
tent, arguing that the ’109 patent claims are unpatentable
as obvious over several prior art references. Claims 1 and
8 are exemplary. Claim 1 recites:
A method of hosting an interactive software appli-
cation comprising:
running at a server the interactive software ap-
plication;
receiving at the server user input signals from
a client device, wherein the user input signals
are used to control updating of the state of the
interactive software application;
generating at least one updated image at the
server in response to updating the state of the
interactive software application; and
compressing the at least one updated image
and transmitting the compressed updated im-
age to the client device, wherein the server
transmits the updated image as a compressed
frame that can be decompressed and displayed
as an updated image at the client device.
’109 patent, claim 1 (emphases added). Claim 8 recites a
system comprising a server that performs the server-side
steps of the method recited in claim 1.
1 Sony originally petitioned for review of claims 1–
18, but IPL filed a statutory disclaimer of claims 13–18,
leaving only claims 1–12 at issue.
Case: 24-2174 Document: 41 Page: 3 Filed: 07/10/2026

-- 3 of 13 --

INTELLECTUAL PIXELS LIMITED v.
SONY INTERACTIVE ENTERTAINMENT LLC
4
The primary relevant prior art reference raised in
Sony’s petition is U.S. Patent No. 6,409,602 (“Wiltshire”).
Wiltshire disclosed a computer gaming system whereby the
game is hosted “exclusively on a server/host computer” but
users play the game through separate “client/terminal
computers.” Wiltshire, col. 2 ll. 35–44. In Wiltshire’s sys-
tem, the client computers also receive input from the user
and transmit it to the host computer, which uses it to select
a new image that is transmitted back to the client com-
puter to be displayed. Id. In one disclosed embodiment,
represented in Figure 2, Wiltshire describes its server exe-
cuting a “game program,” “generat[ing]” an image such as
a “compressed video MPEG stream,” and transmitting that
image to the client for display to the user. Id. fig. 2, col. 7
ll. 7–27. In its definition of “game,” Wiltshire includes
“video[-]based games such as Doom, Pong, Packman [sic],
[and] Myst.” Id. col. 1 ll. 26–44.
II
In the Board’s first final written decision, it concluded
that Sony had not shown that the challenged claims were
unpatentable. The Board concluded that Wiltshire did not
disclose “generating” an image at the server because, in its
view, Wiltshire only disclosed the external server’s “se-
lect[ing]” an image from a predetermined set to display ra-
ther than rendering a new (“updated”) image as the claims
require. J.A. 20. The Board did not reach the question of
whether Wiltshire disclosed the “compressing the at least
one updated image” limitation but did state that “Wilt-
shire’s disclosure [is] completely silent as to the content or
origin of th[e] ‘compressed video MPEG stream.’” J.A. 30
(quoting J.A. 436–37) (first alteration in original).
On appeal, we vacated the Board’s decision and re-
manded, concluding that substantial evidence did not sup-
port the Board’s finding that Wiltshire did not disclose
generating a new image. Sony Interactive Ent. LLC v. In-
tell. Pixels Ltd., No. 2022-2118, 2023 WL 6773879, at *4–5
Case: 24-2174 Document: 41 Page: 4 Filed: 07/10/2026

-- 4 of 13 --

INTELLECTUAL PIXELS LIMITED v.
SONY INTERACTIVE ENTERTAINMENT LLC
5
(Fed. Cir. Oct. 13, 2023). This was so because Wiltshire
disclosed operating its system in connection with the video
game Doom,2 and the parties agreed Doom required gener-
ating a new image. Id. Our decision was limited to “[t]he
Board’s determination that Wiltshire does not disclose the
‘generating’ limitation;” we declined to reach other issues
and “remand[ed] for further proceedings consistent with
th[at] opinion.” Id.
On remand, in accordance with our decision, the Board
recognized that Wiltshire, by disclosing operating its sys-
tem in conjunction with a game like Doom, disclosed the
external server’s generating new updated images and sat-
isfied the generating limitation of the challenged claims.
The Board further found that these new updated images
were transmitted to the client computers as compressed
MPEG streams. Therefore, the Board concluded that the
compressing limitation was also satisfied and issued a sec-
ond final written decision holding the challenged claims
unpatentable as obvious over Wiltshire in combination
with other prior art references.3
2 In Doom, as the Board found, the player’s “perspec-
tive changes dynamically based on what the user is doing
in real time,” so each displayed image must be “updated to
reflect the current state of the player within the game
world.” J.A. 26 (quoting J.A. 2321). Such games must gen-
erate novel updated images in response to user inputs in
real time.
3 The Board held claims 1 and 3–12 unpatentable
over the combination of Wiltshire and U.S. Patent
No. 6,404,817 (“Saha”), which detailed MPEG compres-
sion. The Board held claim 2 unpatentable over the combi-
nation of Wiltshire, Saha, and an article, “The
Development and Standardization of Asymmetrical Digital
Subscriber Line,” IEEE Communications Magazine (May
Case: 24-2174 Document: 41 Page: 5 Filed: 07/10/2026

-- 5 of 13 --

INTELLECTUAL PIXELS LIMITED v.
SONY INTERACTIVE ENTERTAINMENT LLC
6
IPL appeals the Board’s second final written decision.
We have jurisdiction under 28 U.S.C. § 1295(a)(4)(A).
D ISCUSSION
On appeal, IPL argues that (1) the Board acted con-
trary to our mandate in the first appeal; and (2) the Board’s
decision was, in any event, unsupported by substantial ev-
idence. We disagree.
I
We review the scope of our own mandate de novo.
TecSec, Inc. v. Int’l Bus. Machs. Corp., 731 F.3d 1336, 1341
(Fed. Cir. 2013). In doing so, we interpret our mandate in
accordance with “both the letter and the spirit of the man-
date.” Id. at 1342 (quoting Engel Indus. Inc. v. Lockformer
Co., 166 F.3d 1379, 1383 (Fed. Cir. 1999)). As is true for
any other tribunal, the Board on remand may not recon-
sider “any issue within the scope of the judgment [previ-
ously] appealed from.” Amado v. Microsoft Corp., 517 F.3d
1353, 1360 (Fed. Cir. 2008); see also Jewelers Vigilance
Comm., Inc. v. Ullenberg Corp., 853 F.2d 888, 892 & n.3
(Fed. Cir. 1988) (applying the mandate rule to the Patent
and Trademark Office); Atlanta Gas Light Co. v. Bennett
Regulator Guards, Inc., 33 F.4th 1348, 1354–56 (Fed. Cir.
2022) (same); 18B Wright & Miller, Federal Practice & Pro-
cedure § 4478.3 (“An administrative agency is bound by the
mandate of a reviewing court much as a lower court is
bound by the mandate of a higher court.”); Scott v. Mason
Coal Co., 289 F.3d 263, 267–68 (4th Cir. 2002) (holding the
mandate rule applies equally to administrative agencies).
The mandate rule provides that issues actually decided
on appeal are foreclosed from further consideration.
Amado, 517 F.3d at 1360. This rule encapsulates the long-
1999) (“Chen”), which disclosed asymmetric bandwidth
transmissions.
Case: 24-2174 Document: 41 Page: 6 Filed: 07/10/2026

-- 6 of 13 --

INTELLECTUAL PIXELS LIMITED v.
SONY INTERACTIVE ENTERTAINMENT LLC
7
standing principle that a tribunal “has no power or author-
ity to deviate from the mandate issued [to it] by an appel-
late court.” Briggs v. Pa. Ry. Co., 334 U.S. 304, 306 (1948).
When we review a judgment, “all issues within the scope of
the appealed judgment are deemed incorporated within the
mandate and thus are precluded from further adjudica-
tion.” Engel, 166 F.3d at 1383 (collecting cases). However,
the scope of the appealed judgment, and thus our mandate,
“is limited to issues ‘actually decided, either explicitly or by
necessary implication’ in the previous litigation.” Banks
v. United States, 741 F.3d 1268, 1276 (Fed. Cir. 2014)
(quoting Toro Co. v. White Consol. Indus., Inc., 383 F.3d
1326, 1335 (Fed. Cir. 2004)).
Issues “undecided on the merits by the trial court be-
cause they were moot, and thus on appeal unripe, [and]
neither presented to us nor discussed in our opinion, nor
necessary to our disposition of the appeal,” are open on re-
mand. Retractable Techs., Inc. v. Becton Dickinson & Co.,
757 F.3d 1366, 1372 (Fed. Cir. 2014) (quoting Laitram
Corp. v. NEC Corp., 115 F.3d 947, 952 (Fed. Cir. 1997)); see
also TecSec, 731 F.3d at 1343 (following affirmance, dis-
trict court was free to revisit claim construction on remand
where the claim construction was not the basis of the orig-
inal judgment and not addressed on appeal); Omega Pa-
tents, LLC v. CalAmp Corp., 13 F.4th 1361, 1374 (Fed. Cir.
2021) (district court was not bound by earlier evidentiary
finding related to damages where our mandate left open
the issue of damages on remand); Exxon Chem. Pats., Inc.
v. Lubrizol Corp., 137 F.3d 1475, 1478 (Fed. Cir. 1998)
(mandate regarding judgment on literal infringement did
not preclude district court from revisiting doctrine-of-
equivalents infringement which had not previously been
decided by the district court or on appeal).4
4 “[T]here are circumstances in which a federal ap-
pellate court is justified in resolving an issue not passed on
Case: 24-2174 Document: 41 Page: 7 Filed: 07/10/2026

-- 7 of 13 --

INTELLECTUAL PIXELS LIMITED v.
SONY INTERACTIVE ENTERTAINMENT LLC
8
IPL argues that the Board’s second final written deci-
sion exceeded our mandate because in its first final written
decision the Board made two findings not set aside in our
opinion but which the Board did not adhere to on remand.
First, in the first final written decision, the Board con-
cluded that “nothing in Wiltshire . . . suggest[s] that a per-
son of ordinary skill in the art would have understood that
Wiltshire’s system could possibly have supported [Doom]
in the manner proposed by petitioner,” Appellant’s Reply
Br. 11 (quoting J.A. 27), and second, the Board found that
“Wiltshire’s disclosure [is] completely silent as to the con-
tent or origin of that ‘compressed video MPEG stream,’”
Appellant’s Br. 28 (alteration in original) (quoting J.A. 30).
The first finding (that Wiltshire did not disclose the use
of games like Doom) was vacated as unsupported by sub-
stantial evidence in our prior decision. Sony, 2023 WL
6773879, at *5. As we stated in our prior opinion, “Wilt-
shire explicitly discloses that [its] Figure 2 is to be applied
to games like Doom,” which required generating a new im-
age. Id. at *4. The Board then on remand determined that
Wiltshire disclosed “applying its system to video games like
Doom, which require ‘generating’ new images.” J.A. 74
(quoting Sony, 2023 WL 6773879, at *4). This remand de-
termination was compelled by our mandate, not foreclosed
by it.
As to the second Board finding, any fact-finding the
Board conducted regarding the compressing limitation
during its first final written decision was not within the
scope of the Board’s first judgment, which reached only the
generating limitation, was not appealable or decided by us,
below, as where the proper resolution is beyond any doubt
or where injustice might otherwise result.” Singleton
v. Wulff, 428 U.S. 106, 121 (1976) (internal citations and
quotation marks omitted). A lower tribunal would be
bound by any such holdings under the mandate rule.
Case: 24-2174 Document: 41 Page: 8 Filed: 07/10/2026

-- 8 of 13 --

INTELLECTUAL PIXELS LIMITED v.
SONY INTERACTIVE ENTERTAINMENT LLC
9
and thus was not within the scope of our mandate. In its
first final written decision, the Board stated, “[w]e focus
our analysis . . . on the ‘generating’ limitation,” J.A. 16,
and then that “Petitioner has not met its burden to show
by a preponderance of the evidence that a person of ordi-
nary skill in the art would have understood the combina-
tion of Wiltshire and Saha as teaching [the generating
limitation, therefore] Petitioner has not shown that the
subject matter of claims 1 and 8 of the ’109 patent would
have been obvious,” J.A. 32. The Board’s first final written
decision only reached whether the proposed combinations
disclosed “generating at least one updated image.” ’109 pa-
tent, claims 1, 8.
IPL argues that the Board addressed the compressing
limitation when it stated that “Wiltshire’s disclosure [is]
completely silent as to the content or origin of that ‘com-
pressed video MPEG stream.’” J.A. 30 (alteration in origi-
nal) (quoting J.A. 436–37). But the Board did not reach the
compressing limitation issue or consider it as an alterna-
tive or independent basis for supporting the original judg-
ment; instead, it simply commented that the “at least one
updated image” required in both the generating limitation
and the compressing limitation did not exist in Wiltshire.
We also did not address the compressing limitation on ap-
peal. See Sony, 2023 WL 6773879, at *2 (“The sole issue on
appeal is whether the Board properly determined that
Wiltshire does not teach the ‘generating’ limitation.”).
Since the Board’s decision as to obviousness was based
on the generating limitation, any findings of fact as to the
compressing limitation were not subject to appeal, were not
decided by us, and were not part of our mandate. It is well
established that Article III courts review judgments, not
opinions. E.g., Tesco Corp. v. Nat’l Oilwell Varco, L.P.,
804 F.3d 1367, 1379 (Fed. Cir. 2015); Plastic Omnium Adv.
Innov. & Rsch. v. Donghee Am., Inc., 943 F.3d 929, 938
(Fed. Cir. 2019). The parties cannot appeal “issues when it
is not clear that the resolution of the question will resolve
Case: 24-2174 Document: 41 Page: 9 Filed: 07/10/2026

-- 9 of 13 --

INTELLECTUAL PIXELS LIMITED v.
SONY INTERACTIVE ENTERTAINMENT LLC
10
a concrete controversy between interested parties.” Jang
v. Bos. Sci. Corp., 532 F.3d 1330, 1336 (Fed. Cir. 2008).
The parties can only appeal issues that formed the basis
for a judgment. Issues that do not form the basis of the
judgment are outside the scope of an appeal. Id. at 1336–
38 (declining to address appealed claim construction opin-
ion where it was unclear whether claim construction re-
lated to judgment of noninfringement); Personalized User
Model, LLP v. Google Inc., 797 F.3d 1341, 1350 (Fed. Cir.
2015) (same).
This is similar to the situation considered in Laitram
Corp. v. NEC Corp., 115 F.3d 947 (Fed. Cir. 1997). In that
case, following an adverse jury verdict, the defendant filed
three separate motions for judgment as a matter of law
(“JMOL”). Laitram, 115 F.3d at 949. The district court
granted one of those motions and did not reach the other
two. Id. In the first appeal, we reversed with instructions
to “reinstate the jury verdict.” Id. at 952–53. Neverthe-
less, we held that, on remand, the district court could
properly consider the other two JMOL motions because
they were outside the scope of the original judgment. Id.
Similarly, in Atlanta Gas Light Co. v. Bennett Regulator
Guards, Inc., we considered whether the Board could re-
consider its application of a time-bar issue on remand when
the issue was not addressed on appeal and concluded that
our mandate did not preclude the Board from doing so.
33 F.4th at 1355. Laitram and Atlanta Gas were not outli-
ers; the rule that they apply is supported by numerous rel-
evant cases.5 The Board did not err by revisiting the
compressing limitation issue on remand.
5 See, e.g., Clark v. United States, 656 F.3d 1317,
1321 (Fed. Cir. 2011) (trial court did not exceed mandate
when on remand it granted summary judgment on alterna-
tive ground that it had not previously reached and that we
did not decide on appeal); Kashner Davidson Secs. Corp.
Case: 24-2174 Document: 41 Page: 10 Filed: 07/10/2026

-- 10 of 13 --

INTELLECTUAL PIXELS LIMITED v.
SONY INTERACTIVE ENTERTAINMENT LLC
11
Finally, we note that the Board’s finding in the first de-
cision that “Wiltshire’s disclosure [is] completely silent as
to the content or origin of that ‘compressed video MPEG
stream,’” J.A. 30 (alteration in original) (quoting J.A. 436–
37), was also implicitly rejected in the first appeal in our
discussion of the generating limitation. Both the generat-
ing limitation and the compressing limitation disclose an
“at least one updated image.” Therefore, our decision de-
termined that Wiltshire was not “silent as to the content or
origin of that ‘compressed video MPEG stream.’” J.A. 30.
In the context of Doom, the content was a newly generated
“updated image.” Sony, 2023 WL 6773879, at *3. On re-
mand, the Board reached “[t]he logical conclusion from the
Federal Circuit’s reasoning . . . that [its] finding that Wilt-
shire is silent as to the content of that compressed MPEG
v. Mscisz, 601 F.3d 19, 24 (1st Cir. 2010) (district court not
constrained from reaching issue left unaddressed in first
appeal); United States v. Arrington, 757 F.2d 1484, 1485
(4th Cir. 1985) (after reversal, district court could properly
consider on remand an alternative ground for relief that
was not previously reached); Fuller v. United States,
398 F.3d 644, 650 (7th Cir. 2005) (issue not previously
raised was not barred by law of the case doctrine on re-
mand because it had not been previously addressed or de-
cided); Hulsey v. Astrue, 622 F.3d 917, 924 (8th Cir. 2010)
(district court permitted to address on remand alternative
theory that was not the basis of the first appealed decision
or the decision on appeal); Pittsburg Cnty. Rural Water
Dist. No. 7 v. City of McAlester, 358 F.3d 694, 711
(10th Cir. 2004) (after reversal, district court could
properly address alternative grounds on remand that were
not previously addressed); Transam. Leasing, Inc. v. Inst.
of Lond. Underwriters, 430 F.3d 1326, 1332 (11th Cir.
2005) (district court properly reached alternative issue on
remand where the issue “was not addressed in the [first
appealed] district court order”).
Case: 24-2174 Document: 41 Page: 11 Filed: 07/10/2026

-- 11 of 13 --

INTELLECTUAL PIXELS LIMITED v.
SONY INTERACTIVE ENTERTAINMENT LLC
12
stream has now been rejected.” Appellant’s Br. 30 (empha-
sis omitted) (quoting J.A. 93).
IPL nonetheless argues that our decision in Bitman-
agement Software GmBH v. United States, 124 F.4th 1368
(Fed. Cir 2025) (“Bitmanagement IV”) is to the contrary.
That case suggested that it would have been inappropriate
for the Court of Federal Claims (the “Claims Court”) to re-
visit certain prior findings of fact after appeal. Id. at 1377.
We stated, “many of the findings on which the [Claims
Court] based its damages award are not (and cannot be)
challenged: they were findings originally made in connec-
tion with the first trial and were before us—but not dis-
turbed by us—in [the first appeal]. Hence, as the trial
court recognized, these findings cannot be challenged at
this stage.” Id.
That decision is not contrary to our decision in this case
or the numerous cases that support our decision. In the
first appeal in Bitmanagement, we vacated a Claims Court
judgment of copyright noninfringement in favor of the gov-
ernment. Bitmanagement Software GmBH v. United
States, 989 F.3d 938, 950–51 (Fed. Cir. 2021) (“Bitmanage-
ment II”). We concluded that while the government had an
implied-in-fact license to use the copyrighted works, the
government exceeded the scope of the license. Id. In the
second appeal, we addressed the issue of damages, conclud-
ing that the relevant findings on the implied license issue
supported the damages decision. Bitmanagement IV,
124 F.4th at 1377. Those findings were within the scope of
the first appealed judgment because those facts were the
basis of the Claims Court’s conclusion that the United
States had an implied-in-fact license, an issue within the
scope of the first appeal. Compare Bitmanagement Soft-
ware GmbH v. United States, 144 Fed. Cl. 646, 648–654
(2019) (“Bitmanagement I”) with Bitmanagement Software
GmbH v. United States, No. 16-840C, 2022 WL 17077251,
at *2–3 (Cl. Ct. Nov. 1, 2022) (“Bitmanagement III”).
Case: 24-2174 Document: 41 Page: 12 Filed: 07/10/2026

-- 12 of 13 --

INTELLECTUAL PIXELS LIMITED v.
SONY INTERACTIVE ENTERTAINMENT LLC
13
Here, neither the Board’s first final written decision
nor our decision on appeal reached whether the compress-
ing limitation was disclosed in the prior art. Any Board
findings as to this issue were not within the scope of the
appeal.
II
IPL alternatively argues that the Board’s second final
written decision is not supported by substantial evidence.
Specifically, IPL argues that Wiltshire does not teach com-
pression of newly generated images into an MPEG stream.
This argument is unpersuasive. Sony argued in its petition
that the compressing limitation was disclosed through a
combination of Wiltshire and Saha. While Wiltshire gen-
erally disclosed transmitting a compressed image to the cli-
ent device based on the described compressed MPEG
stream, Saha provided information on predominant MPEG
standards that met the compressing claim limitation that
“the server transmits the updated image as a compressed
frame that can be decompressed and displayed.” J.A. 194–
95 (internal quotation marks omitted). The Board agreed,
crediting both the text of Wiltshire and Saha as well as ex-
pert testimony presented that a skilled artisan would have
been familiar with real-time image compression via MPEG
compression and would have combined Saha’s standard for
compressing and decompressing an MPEG stream with
Wiltshire’s system. This is substantial evidence support-
ing the Board’s decision.
AFFIRMED
COSTS
Costs to Sony.
Case: 24-2174 Document: 41 Page: 13 Filed: 07/10/2026

-- 13 of 13 --