United States Court of Appeals 

for the Federal Circuit ______________________

HUNTING TITAN, INC.,

Appellant

v.

DYNAENERGETICS EUROPE GMBH,

Cross-Appellant

ANDREW HIRSHFELD, PERFORMING THE 

FUNCTIONS AND DUTIES OF THE UNDER 

SECRETARY OF COMMERCE FOR 

INTELLECTUAL PROPERTY AND DIRECTOR OF 

THE UNITED STATES PATENT AND TRADEMARK 

OFFICE,

Intervenor

______________________

2020-2163, 2020-2191

______________________

Appeals from the United States Patent and Trademark 

Office, Patent Trial and Appeal Board in No. IPR2018-

00600.

______________________

Decided: March 24, 2022

______________________

JASON SAUNDERS, Arnold & Saunders, LLP, Houston, 

TX, argued for appellant. Also represented by GORDON 

ARNOLD, CHRISTOPHER MCKEON.

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2 HUNTING TITAN, INC. v. DYNAENERGETICS EUROPE GMBH

 BARRY J. HERMAN, Womble Bond Dickinson (US) LLP, 

Baltimore, MD, argued for cross-appellant. Also represented by WILLIAM R. HUBBARD; CHRISTINE H. DUPRIEST,

PRESTON HAMILTON HEARD, Atlanta, GA; LISA MOYLES, 

JASON ROCKMAN, Moyles IP, LLC, Shelton, CT.

 SARAH E. CRAVEN, Office of the Solicitor, United States 

Patent and Trademark Office, Alexandria, VA, argued for 

intervenor. Also represented by THOMAS W. KRAUSE,

ROBERT J. MCMANUS, MAUREEN DONOVAN QUELER, 

FARHEENA YASMEEN RASHEED.

______________________

Before PROST, REYNA, and HUGHES, Circuit Judges.

Opinion for the court filed by Circuit Judge HUGHES.

Concurring opinion filed by Circuit Judge PROST.

HUGHES, Circuit Judge.

Hunting Titan, Inc. petitioned for inter partes review 

of claims 1–15 of U.S. Patent No. 9,581,422, asserting 16

grounds of unpatentability based on theories of anticipation and obviousness, including allegations that the claims 

were anticipated by Schacherer, U.S. Patent No. 9,689,223. 

The Board instituted trial on all grounds and ultimately 

agreed with Hunting Titan, finding all of the original 

claims unpatentable.

After the petition was instituted, DynaEnergetics Europe GmbH, the patent owner, moved to amend the ’422 patent to add proposed substitute claims 16–22. Hunting 

Titan opposed the motion to amend, advancing only obviousness grounds. Although Hunting Titan did not assert 

that Schacherer anticipated the proposed substitute 

claims, the Board determined that the original and proposed substitute claims alike were unpatentable as anticipated by Schacherer. DynaEnergetics requested rehearing 

and Precedential Opinion Panel review of the Board’s 

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HUNTING TITAN, INC. v. DYNAENERGETICS EUROPE GMBH 3

denial of the motion to amend. The Panel granted 

DynaEnergetics’s request for rehearing, vacated the 

Board’s decision denying DynaEnergetics’s motion to 

amend, and then—after concluding that Hunting Titan 

had not proven by a preponderance of the evidence that 

proposed substitute claims 16–22 are unpatentable—

granted the motion to amend the ’422 patent to add the 

proposed substitute claims.

Hunting Titan appeals the Precedential Opinion 

Panel’s vacatur of the Board’s decision denying the motion 

to amend, and DynaEnergetics cross-appeals the Board’s 

decision finding the original claims of the ’422 patent anticipated by Schacherer. We affirm on both grounds.

I

DynaEnergetics owns the ’422 patent, which is directed to a perforating gun used in an oil wellbore to penetrate the well lining and surrounding rock formation in 

order to provide a flow path for oil into the wellbore from 

the surrounding rock formation. ’422 patent, 1:15–44. The

perforating gun’s key feature is a “wireless” and “selective” 

detonator assembly for detonating an explosive projectile 

charge within the perforating gun “without the need to attach wires to the detonator.” Id. 2:24–34. Claim 1 is representative and is reproduced below.

1. A wireless detonator assembly configured for being electrically contactably received within a perforating gun assembly without using a wired 

electrical connection, comprising:

a shell configured for housing components 

of the detonator assembly;

more than one electrical contact component, wherein at least one of the electrical 

contact components extends from the shell 

and further wherein the electrical contact 

component comprises an electrically 

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4 HUNTING TITAN, INC. v. DYNAENERGETICS EUROPE GMBH

contactable line-in portion, an electrically 

contactable line-out portion and an electrically contactable ground portion, the 

ground portion in combination with the 

line-in portion and the line-out portion being configured to replace the wired electrical connection to complete an electrical 

connection merely by contact;

an insulator positioned between the line-in 

portion and the line-out portion, wherein 

the insulator electrically isolates the linein portion from the line-out portion; and

means for selective detonation housed 

within the shell, wherein the detonator assembly is configured for electrically contactably forming the electrical connection 

merely by the contact.

Id. 8:39–61.

A

Hunting Titan petitioned for inter partes review of 

claims 1–15 of the ’422 patent, asserting 16 grounds of unpatentability based on theories of anticipation and obviousness. The Board instituted on the petition. Appx246.

DynaEnergetics opposed the petition. It also filed a contingent motion to amend the ’422 patent to add new claims 

16–22, in the event the Board were to find original claims

5–11 unpatentable.

1

Relevant to this appeal is Hunting Titan’s first asserted ground of unpatentability that Schacherer, U.S. Patent No. 9,689,223, anticipates all of the ’422 patent’s 

original claims. DynaEnergetics maintained, in its Patent 

Owner Response, that Schacherer lacks several limitations 

of the claimed detonator assembly.

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HUNTING TITAN, INC. v. DYNAENERGETICS EUROPE GMBH 5

DynaEnergetics asserted that Schacherer does not 

teach or disclose the claimed “wireless detonator assembly.” Appx320 (emphasis added). According to DynaEnergetics, Schacherer “incorporate[s] an electrically wired 

detonator (38) into a tandem sub or connector,” id., while

the claimed detonator assembly “replace[s] [the] electrically wired detonator . . . with a wireless detonator 10 and 

house[s] the components of the detonator, including the 

means for selective detonation, within a shell (12).” 

Appx321. DynaEnergetics also argued that “Schacherer 

does not teach or suggest incorporating the selecting firing 

module (32) into the wired detonator (38),” but instead “describes a [tandem] sub for housing such components.” 

Appx322–23. Thus, according to DynaEnergetics, 

“Schacherer does not teach or suggest a shell configured for 

housing components of the detonator assembly.” Appx323.

Because these limitations, among others not relevant 

to this appeal, are allegedly not taught by Schacherer, 

DynaEnergetics argued that Hunting Titan failed to 

“show[] that Schacherer anticipates [any] of the challenged 

claims of the ’422 [p]atent.” Appx333. The Board disagreed 

with DynaEnergetics, concluding that each original claim 

is unpatentable as anticipated by Schacherer. Appx24.

Significant to this appeal, the Board first considered 

claim 1’s uncontested limitations and found these limitations fully supported by the record and “effectively admitted” by DynaEnergetics. Appx9. The Board accordingly 

concluded that Hunting Titan had met its burden of proving that Schacherer discloses a “detonator assembly” that

is:

(1) “received with a perforating gun,”

(2) has “more than one electrical contact component, wherein at least one of the electrical contact 

components . . . comprises an electrically contactable line-in portion, . . . line-out portion[,] and . . . 

ground portion,” and

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6 HUNTING TITAN, INC. v. DYNAENERGETICS EUROPE GMBH

(3) has “means for selective detonation,” as recited 

in representative claim 1.

Appx9–10. The Board then addressed whether Schacherer 

teaches or suggests the remaining limitations that are purportedly missing from the prior art reference.

Beginning with claim 1’s “wireless detonator assembly” limitation, the Board said that “DynaEnergetics [had] 

oversimplifie[d] what constitutes Schacherer’s detonator 

assembly and ignore[d] the express language of the [representative] claim” in the ’422 patent. Appx13. The Board explained that, “consistent with the claim language and 

specification, the ‘wireless’ and ‘merely by the contact’ limitations speak expressly to how one assembly forms an electrical connection with the other assembly—through bodily 

contact as opposed to connection of physical wires.” Id. But 

“nowhere does the ’422 patent preclude the use of wired 

connections internal to the detonator assembly.” Id.

Still, the Board observed, DynaEnergetics attempted to 

fall back on a third, related limitation—i.e., “without using 

a wired connection”—when it “distort[ed] the [clarifying] 

testimony of Hunting Titan’s expert,” Appx15, and 

“fault[ed] Schacherer for using a wired connection between 

subcomponents of the detonator assembly,” Appx13–14. 

“What DynaEnergetics fail[ed] to acknowledge,” however, 

was “that the claimed ‘wireless,’ ‘without using a wired connection,’ and ‘merely by the contact’ limitations pertain 

solely to how the detonator assembly as a whole forms an 

electrical connection with the perforating gun assembly as 

a whole, irrespective of how any subcomponents with each 

assembly are connected.” Appx15. And because “the claims 

require only the absence of a wired connection between the 

detonator assembly and the perforating gun assembly,” the 

Board “conclude[d] that Schacherer is a ‘wireless’ detonator assembly in the manner recited by claim 1” since its 

“detonator assembly achieves an electrical connection with 

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HUNTING TITAN, INC. v. DYNAENERGETICS EUROPE GMBH 7

the perforating gun assembly merely by contact of one with 

the other.” Appx16.

The Board also determined that Schacherer discloses

claim 1’s “shell configured for housing components of the 

detonator assembly.” In reaching this determination, the 

Board construed “shell” to mean “a shell, housing, or casing 

for housing any component of the detonator assembly, including but not limited to a detonator head plug, a fuse 

head, an electronic circuit board, or explosive components.” 

Appx17. It then found that this construction “matches exactly the structure and function” of Schacherer’s connector 30. Appx19. The Board thus dismissed 

DynaEnergetics’s arguments “as nothing more than semantics.” Id.

Having determined “that a skilled artisan would have 

understood Schacherer as disclosing each and every limitation of claim 1,” the Board then determined the same 

with respect to each limitation of independent claims 5 

and 12 as well as the claims depending therefrom. 

Appx24–25.

2

Contingent on the Board finding original claims 5–11 

unpatentable, DynaEnergetics also moved the Board to 

amend the ’422 patent to add proposed substitute 

claims 16–22. The substitute claims would retain all the 

limitations of the original claims and further add the following new limitations:

1) “a perforating gun housing” having “a detonator 

assembly contained entirely within the perforating 

gun housing,”

2) “a carrying device positioned within the perforating gun housing to hold at least one shaped 

charge,” and

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8 HUNTING TITAN, INC. v. DYNAENERGETICS EUROPE GMBH

3) “a detonator assembly contained entirely within 

the perforating gun housing.”

Appx419, 429. DynaEnergetics asserted that these “contingent amendments further clarify that the detonator assembly includes a means for selective detonation within the 

shell, in addition to at least one electrically contactable 

component extending from the shell, all designed in a way 

that replaces wires and instead completes an electrical connection within the perforating gun housing merely by contact.” Appx419; see also Appx429. These proposed 

substitute claims are therefore patentable and not anticipated by Schacherer, according to DynaEnergetics, because Schacherer’s detonator assembly is not wireless and 

its “selective detonator assembly . . . is clearly not contained within its perforating gun housing.” Appx430–31. 

So DynaEnergetics argued that Schacherer “does not teach 

or disclose a ‘wirelessly connectable selective detonator assembly’ that is ‘contained entirely within the perforating 

gun housing without using a wired electrical connection’ as 

recited in” its proposed substitute claims. Appx431.

Hunting Titan opposed the motion to amend, asserting 

that the proposed substitute claims “d[id] not overcome the 

previously cited prior art in the Petition.” Appx524. Hunting Titan identified two publications—U.S. Patent 

No. 10,077,641 (Rogman) and U.S. Patent Application 

No. 14/888,882 (Harrigan)—that, it contended, “disclose all 

of the additional claim limitations in proposed amended 

claims 16–22 and would have been obvious to combine with 

the previously cited prior art.” Appx524. It also identified 

as pertinent several previously cited prior art references—

including Schacherer—and asserted that each of these references discloses or teaches every claim limitation of the 

proposed substitute claims. Appx524–44. Based on these 

assertions, Hunting Titan maintained that the proposed 

substitute claims are obvious and therefore unpatentable.

Hunting Titan “presented only obviousness arguments, 

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HUNTING TITAN, INC. v. DYNAENERGETICS EUROPE GMBH 9

without alleging that the proposed substitute claims were 

anticipated by the prior art of record.” Appx33.

“In [the Board’s] view, none of [DynaEnergetics’s] additional limitations render[ed] the proposed substitute 

claims novel or non-obvious over the prior art of record. Instead,” the Board held, “each of [the additional] limitations

is taught by the prior art, either as admitted in the ’422 patent itself or as disclosed by Schacherer.” Appx26. The 

Board thus decided that “Hunting Titan ha[d] carried its 

burden in showing that DynaEnergetics’[s] proposed 

amendments d[id] not overcome the anticipatory nature of 

Schacherer’s disclosure,” and it denied DynaEnergetics’s

motion to amend. Appx29. In reaching this decision, the 

Board “addresse[d] only Hunting Titan’s anticipation challenge based on Schacherer . . . . [It] render[ed] no findings 

or conclusions as to Hunting Titan’s numerous obviousness 

challenges.”1 Appx34.

B

DynaEnergetics requested rehearing and Precedential 

Opinion Panel review of the Board’s denial of the motion to 

amend. The Panel granted DynaEnergetics’s request for review to address “[u]nder what circumstances and at what 

time during an inter partes review . . . the Board [may] 

raise a ground of unpatentability that a petitioner did not 

advance or insufficiently developed against substitute proposed claims in a motion to amend[.]” Appx34.

The Panel acknowledged that our decision in Nike, Inc. 

v. Adidas AG, 955 F.3d 45 (Fed. Cir. 2020), had “resolve[d] 

1 In a footnote and without further explanation, the 

Board found “persuasive” Hunting Titan’s argument that a 

particular modification to Schacherer would have been obvious as “within the purview of Schacherer and the general 

knowledge of a skilled artisan.” Appx29 n.5; see also 

Appx34 n.2.

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10 HUNTING TITAN, INC. v. DYNAENERGETICS EUROPE GMBH

the question of whether the Board may advance a ground 

of unpatentability that a petitioner does not advance, or insufficiently develop[s], against substitute claims proposed 

in a motion to amend,” and it agreed that Nike had answered this question in the affirmative. Appx39. But the 

Panel said, Nike “d[id] not address the circumstances in 

which the Board should advance such a ground of unpatentability in relation to substitute claims proposed in a 

motion to amend.” Appx40. And the Panel “conclude[d] that 

only under rare circumstances should the need arise for the 

Board to advance grounds of unpatentability to address 

proposed substitute claims that the petitioner did not advance, or insufficiently developed, in its opposition to the 

motion.” Appx40.

The Panel believed that “the better approach, in most 

instances, is to rely on the incentives the adversarial system creates, and expect that the petitioner will usually 

have an incentive to set forth the reasons why the proposed 

substitute claims are unpatentable.” Appx43. Still, the 

Panel left open the possibility for the Board to sua sponte 

raise a ground of unpatentability, but “only . . . under rare 

circumstances,” such as when a petitioner “cease[s] to participate in the proceeding altogether” or “chooses not to oppose the motion to amend.” Appx43–44. The Panel further

accepted that “there may be circumstances where certain 

evidence of unpatentability has not been raised by the petitioner, but is readily identifiable and persuasive such 

that the Board should take it up in the interest of supporting the integrity of the patent system, notwithstanding the 

adversarial nature of the proceedings.” Appx44. Although 

the Panel chose not “to delineate [every situation] with particularity,” it did put forth one exemplary situation: “where 

the record readily and persuasively establishes that substitute claims are unpatentable for the same reasons that corresponding original claims are unpatentable.” Appx44. In 

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HUNTING TITAN, INC. v. DYNAENERGETICS EUROPE GMBH 11

specific” and gave the Board discretion to “address them as 

they arise.” Appx44.

The Panel then observed that Hunting Titan had 

“never mentioned anticipation as a ground” of unpatentability against the proposed substitute claims. Appx48. It 

further rejected Hunting Titan’s assertion that its anticipation arguments against the original claims, found in its 

petition, were “sufficient to also raise arguments regarding 

anticipation of the proposed substitute claims by 

Schacherer.” Appx48. And because “raising a ground of unpatentability in a petition against original claims in a patent does not provide a patent owner with sufficient notice 

that new arguments would be asserted using that same reference against new substitute claims proposed in a motion 

to amend,” the Panel concluded that “the anticipation 

ground based on Schacherer . . . was not advanced, much 

less sufficiently developed, by [Hunting Titan] against proposed substitute claims 16–22.” Appx49.

Although anticipation based on Schacherer was not 

raised by Hunting Titan, the Panel asked “whether the 

Board should [still] have raised that ground against the 

proposed substitute claims in the Final Written Decision.” 

Appx49–50. It decided that the circumstances of this case 

did not “qualify as one of the rare circumstances necessitating the Board to advance a ground of unpatentability 

that Petitioner did not advance or sufficiently develop.” 

Appx50. In doing so, the Panel faulted Hunting Titan for 

its strategic choice “to oppose the motion to amend on different grounds,” holding that “an unsuccessful strategy 

alone does not reflect a failure of the adversarial process 

here that might otherwise support the Board’s decision to 

exercise its discretion to sua sponte raise a new ground of 

unpatentability.” Appx50–51.

The Panel further rejected Hunting Titan’s and supporting amici’s arguments that “the public interest w[ould] 

be harmed by the issuance of substitute claims that the 

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12 HUNTING TITAN, INC. v. DYNAENERGETICS EUROPE GMBH

[]PTO knows to be unpatentable” “if the Board cannot raise 

the Schacherer anticipation ground” here. Appx51. “The 

public interest is preserved,” the Panel claimed, “by a wellfunctioning adversarial system, which, in contrast to reexamination, is the basic set-up Congress envisioned for inter 

partes reviews.” Id. So in a case like this one, where Hunting Titan “vigorously prosecuted its case but made a tactical decision not to raise anticipation arguments,” the Panel

explained, “the adversarial system has not failed” and 

“[t]he public interest [wa]s not well-served by the [PTO] 

filling in gaps intentionally left void by” the petitioner. Id.

The Panel therefore “conclude[d] that, as a policy matter,

the Board should not have raised the Schacherer anticipation ground.” Appx50. Moreover, the Panel stated, this case 

was not one that “present[ed] the potential for issuing substitute claims the [PTO] ‘knows to be unpatentable’” because the PTO “d[id] not have sufficient information on the 

record of this case . . . to make requisite findings on anticipation.” Appx52. According to the Panel, this case did not 

contain “the sort of readily identifiable and persuasive evidence of anticipation in the record that would justify the 

Board raising its own grounds of unpatentability.” Id.

Having determined that the Board should not have itself advanced the ground of anticipation based on 

Schacherer when Hunting Titan raised this ground of unpatentability only against the original claims and not the 

proposed substitute claims, the Panel proceeded to consider in the first instance Hunting Titan’s obviousness “arguments and cited evidence” raised in its opposition to 

DynaEnergetics’s motion to amend. Appx54. The Panel

“conclude[d] that [Hunting Titan] ha[d] not set forth an adequate case of obviousness.” Id. Rather, the Panel observed, Hunting Titan had “merely present[ed] how one or 

more of the various asserted prior art references separately 

teaches the various limitations of proposed substitute 

claims 16–22.” Appx56. It had “provide[d] no discussion of 

a reason to combine or modify the prior art,” and the Panel

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HUNTING TITAN, INC. v. DYNAENERGETICS EUROPE GMBH 13

“decline[d] to piece together [its] arguments” and “develop 

a persuasive theory of unpatentability” on Hunting Titan’s 

behalf. Id. Thus, following its holding that “the obviousness 

grounds that [Hunting Titan] purport[ed] to have raised 

[we]re facially insufficient to support a finding of unpatentability,” the Panel granted the motion to amend. 

Appx56–57.

Hunting Titan timely appealed the Panel’s decision vacating the Board’s denial of DynaEnergetics’s motion to 

amend. DynaEnergetics timely cross-appealed the Board’s 

decision invalidating its original claims. We have jurisdiction under 28 U.S.C. § 1295(a)(4)(A).

II

We review the Board’s decisions in accordance with the 

Administrative Procedure Act, 5 U.S.C. § 706. HTC Corp. 

v. Cellular Commc’ns Equip., LLC, 877 F.3d 1361, 1367 

(Fed. Cir. 2017). We therefore “review the Board’s legal 

conclusions de novo and its factual findings for substantial 

evidence.” Id. Because “[a]nticipation is a question of fact,”

we consider whether substantial evidence supports the 

Board’s determination holding the original claims unpatentable as anticipated by Schacherer. SynQor, Inc. v. 

Artesyn Techs., Inc., 709 F.3d 1365, 1373 (Fed. Cir. 2013). 

“Substantial evidence review asks ‘whether a reasonable 

fact finder could have arrived at the agency’s decision’ and 

requires examination of the ‘record as a whole, taking into 

account evidence that both justifies and detracts from an 

agency’s decision.’” Intelligent Bio-Systems, Inc. v. Illumina 

Cambridge Ltd., 821 F.3d 1359, 1366 (Fed. Cir. 2016) (citation omitted). “Where two different conclusions may be 

warranted based on the evidence of the record, the Board’s 

decision to favor one conclusion over the other is the type 

of decision that must be sustained by this court as supported by substantial evidence.” In re Chudik, 851 F.3d 

1365, 1371 (Fed. Cir. 2017) (citation omitted).

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A

We first address DynaEnergetics’s cross-appeal, challenging the Board’s decision holding the original claims of 

the ’422 patent unpatentable as anticipated by Schacherer.

DynaEnergetics primarily takes issue with the Board’s 

finding that Schacherer teaches a detonator assembly that 

is received within a perforating gun assembly. Specifically, 

DynaEnergetics faults the Board for identifying this limitation as uncontested, fully supported by the record, or effectively admitted, and contends that the Board’s conduct 

erroneously shifted the burden of persuasion from Petitioner to Patent Owner. But the Board identified where in 

the petition Hunting Titan had shown how Schacherer discloses the uncontested limitations. Appx9. And “[t]he 

Board, having found the only disputed limitations together 

in one reference, was not required to address undisputed 

matters.” In re NuVasive, Inc., 841 F.3d 966, 974 (Fed. Cir. 

2016).

For the same reason, we are not persuaded by 

DynaEnergetics’s argument that the Board’s purported 

“failure to analyze the ‘received within’ feature infected its 

construction of the ‘shell’ limitation” and its determination 

that “Schacherer disclosed a shell,” such that “neither is 

supported by substantial evidence.” Cross-Appellant’s 

Opening Br. 25. Moreover, DynaEnergetics’s arguments 

addressing the wireless detonator assembly’s “shell” component—which fault Schacherer’s sub for its size and assert that this sub “cannot reasonably be said to be 

configured for being received within the perforating gun assembly” since it is “a large structural element or heavy 

steel tool that [instead] provides a connection between 

guns,” id. at 27—overlook the fact that the Board construed 

“shell” to include “casing for housing any component of the 

detonator assembly,” Appx16–17. So, since the shell houses

at least part of the detonator assembly and since the detonator assembly is received within the perforating gun 

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HUNTING TITAN, INC. v. DYNAENERGETICS EUROPE GMBH 15

assembly, substantial evidence supports the Board’s finding that the shell is configured to be received within the 

perforating gun assembly. See Appx15–19.

Lastly, DynaEnergetics contends that substantial evidence does not support the Board’s findings that 

Schacherer discloses the claimed “wireless detonator assembly” because the Board did not satisfactorily explain 

why it dismissed DynaEnergetics’s evidence in favor of 

Hunting Titan’s evidence. But the Board’s explanation was 

more than satisfactory. It expressly disagreed with 

DynaEnergetics’s narrow construction of “detonator assembly,” specifically noting that “[w]hat DynaEnergetics 

fails to acknowledge is that the claimed ‘wireless,’ ‘without 

using a wired connection,’ and ‘merely by the contact’ limitations pertain solely to how the detonator assembly as a 

whole forms an electrical connection with the perforating 

gun assembly as a whole, irrespective of how any subcomponents within each assembly are connected.” Appx15. 

And, in light of its construction, the Board explicitly 

pointed to DynaEnergetics’s failure to provide evidentiary 

support or an explanation for why its position—that “a 

wired connection residing entirely within, and internal to, 

Schacherer’s detonator assembly precludes the assembly 

from being ‘wireless’”—was the correct and necessary one 

for the Board to adopt. Appx16. Substantial evidence supports the Board’s determination that the detonator assembly’s electrical connection with the perforating gun 

assembly does not use a wired electrical connection in 

Schacherer. Appx16.

For the foregoing reasons, substantial evidence supports the Board’s determination that Schacherer anticipates all of the ’422 patent’s original claims.

B

Because we affirm the Board’s decision holding the 

original claims unpatentable, we address Hunting Titan’s 

appeal challenging the Panel’s decision to vacate the 

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16 HUNTING TITAN, INC. v. DYNAENERGETICS EUROPE GMBH

Board’s denial of the motion to amend. Hunting Titan contends that, under Aqua Products, Inc. v. Matal, 872 F.3d 

1290, 1325–26 (Fed. Cir. 2017) (en banc) and Nike, Inc. v. 

Adidas AG, 955 F.3d 45, 51–52 (Fed. Cir. 2020), the Board

has a duty to determine the patentability of the proposed 

substitute claims based on the entirety of the record. Hunting Titan asserts that the Panel therefore erred in reversing the Board’s decision finding the proposed claims 

anticipated by Schacherer and further erred in determining the patentability of the proposed substitute claims 

based only on its review of Hunting Titan’s opposition to 

the motion to amend. In other words, Hunting Titan argues 

that the Board had an obligation to sua sponte identify patentability issues for a proposed substitute claim based on 

the prior art of record, and that the Panel committed legal 

error by vacating the Board’s decision to do so in this case. 

We disagree.

Neither Aqua Products nor Nike established that the

Board maintains an affirmative duty, without limitation or 

exception, to sua sponte raise patentability challenges to a 

proposed substitute claim. Nike, 955 F.3d at 51 (“We addressed the universe of prior art that the Board should consider when reviewing a motion to amend in Aqua 

Products. . . . We expressly declined to address, however, 

whether the Board ‘may sua sponte raise patentability 

challenges of amended claims.’” (citation omitted)); id. (“We 

hold today that the Board may sua sponte identify a patentability issue for a proposed substitute claim based on 

the prior art of record.” (emphasis added)). Indeed, as the 

Panel correctly pointed out, “Nike resolve[d] the question 

of whether the Board may advance a ground of unpatentability that a petitioner does not advance, or insufficiently 

develop[s], against substitute claims proposed in a motion 

to amend.” Appx39. But Nike left unanswered “the circumstances in which the Board should advance such a ground 

of unpatentability in relation to substitute claims proposed 

in a motion to amend.” Appx40. It was this question that

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HUNTING TITAN, INC. v. DYNAENERGETICS EUROPE GMBH 17

the Panel answered here, and confining the circumstances 

in which the Board should sua sponte raise patentability 

issues was not itself erroneous.

Notably, we do find problematic the Panel’s reasoning 

behind its decision to confine the Board’s discretion to sua 

sponte raise patentability issues to only rare circumstances. For example, while the adversarial system proves 

useful in IPR proceedings to bring forth evidence the 

agency might not have otherwise discovered, the Panel’s 

substantial reliance on the adversarial system as the basis 

for confining its patentability determination for new claims 

overlooks the basic purpose of IPR proceedings: to reexamine an earlier agency decision and ensure “that patent 

monopolies are kept within their legitimate scope.” Oil 

States Energy Servs., LLC v. Greene’s Energy Grp., LLC, 

138 S. Ct. 1365, 1374 (2018) (cleaned up). And “[t]he fact 

that Congress has enlisted the assistance of private parties 

does not change their essential character.” Regents of Univ. 

of Minn. v. LSI Corp., 926 F.3d 1327, 1338 (Fed. Cir. 2019); 

see also id. (“[A]lthough these modifications to inter partes 

reexamination make IPR [proceedings] ‘look[] a good deal 

more like civil litigation,’ fundamentally these proceedings 

continue to be a ‘second look at an earlier administrative 

grant of a patent.’” (third alteration in original) (citations 

omitted)).

Nevertheless, the Panel’s conclusion, at least to the extent at issue here, is not inconsistent with Nike and Aqua 

Products. The Panel identified circumstances in which the 

Board should advance “a ground of unpatentability that a 

petitioner did not advance, or insufficiently developed, 

against substitute claims in a motion to amend.” Appx44.

And it acknowledged that “even where both a petitioner 

and patent owner participate in the motion to amend process, there may be situations where certain evidence of unpatentability has not been raised by the petitioner, but is 

readily identifiable and persuasive such that the Board 

should take it up in the interest of supporting the integrity 

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18 HUNTING TITAN, INC. v. DYNAENERGETICS EUROPE GMBH

of the patent system” (the readily identifiable evidence exception). Id.

Notably, however, the Panel highlighted one example 

in which the readily identifiable evidence exception could 

apply: “where the record readily and persuasively establishes that substitute claims are unpatentable for the same 

reasons that corresponding original claims are unpatentable.” Id. It was on this basis that the Panel concluded that 

the Board should not have considered whether the proposed substitute claims were anticipated by Schacherer, 

and the Panel therefore confined its own consideration to 

the grounds of unpatentability advanced by Hunting Titan 

in its opposition to DynaEnergetics’s motion to amend. In 

other words, the Panel did not preclude the Board from considering the entirety of the record, but instead determined 

that certain evidence of anticipation—evidence that Hunting Titan contends on appeal should have been considered 

when determining patentability—was not readily identifiable and persuasive. Yet, on appeal, Hunting Titan did not 

challenge the Panel’s decision as an abuse of discretion. 

That is, Hunting Titan failed to argue that the Panel misapplied the readily identifiable evidence exception. Because Hunting Titan raised no such argument, it is 

forfeited.2

2 It does strike us as odd, however, that the Panel 

determined that the Schacherer anticipation ground was 

not readily identifiable and persuasive such that the Board 

should have sua sponte raised this ground of unpatentability against DynaEnergetics’s proposed substitute claims. 

Indeed, the Board specifically found the proposed substitute claims unpatentable for the same reasons it found the 

corresponding original claims unpatentable. Moreover, 

when the Board finds an original claim unpatentable as anticipated by a prior art reference, it would seem to follow 

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HUNTING TITAN, INC. v. DYNAENERGETICS EUROPE GMBH 19

We must therefore affirm the Panel’s decision granting 

the motion to amend. We emphasize, however, that this affirmance is based only on this narrow ground. We are not 

determining the patentability of the proposed substitute 

claims, nor are we deciding whether the Panel abused its 

discretion in determining that the Schacherer anticipation 

ground was not readily identifiable and persuasive such 

that the Board should have sua sponte raised this ground 

of unpatentability. Likewise, we are not opining on the 

other limitations that the Panel placed on the Board’s ability to advance patentability issues not raised by a petitioner, and whether those limitations are consistent with 

35 U.S.C. § 318. Cf. Samsung Elecs. Am., Inc. v. Prisua 

Eng’g Corp., 948 F.3d 1342, 1352 (Fed. Cir. 2020). Finally, 

we do not decide whether the Board has an independent 

obligation to determine patentability of proposed substitute claims. These questions need not be answered to resolve the appeal before us.

CONCLUSION

We affirm the Board’s decision holding claims 1–15 unpatentable, and we also affirm the Panel’s decision granting DynaEnergetics’s motion to amend the ’422 patent to 

add new claims 16–22.

AFFIRMED

COSTS

No costs.

that the Board should begin by first asking if the corresponding proposed substitute claim overcomes the ground 

on which it found the original claim unpatentable.

Case: 20-2163 Document: 59 Page: 19 Filed: 03/24/2022
United States Court of Appeals 

for the Federal Circuit ______________________

HUNTING TITAN, INC.,

Appellant

v.

DYNAENERGETICS EUROPE GMBH,

Cross-Appellant

ANDREW HIRSHFELD, PERFORMING THE 

FUNCTIONS AND DUTIES OF THE UNDER 

SECRETARY OF COMMERCE FOR 

INTELLECTUAL PROPERTY AND DIRECTOR OF 

THE UNITED STATES PATENT AND TRADEMARK 

OFFICE,

Intervenor

______________________

2020-2163, 2020-2191

______________________

Appeals from the United States Patent and Trademark 

Office, Patent Trial and Appeal Board in No. IPR2018-

00600.

______________________

PROST, Circuit Judge, concurring.

I join the majority’s opinion, agreeing that Hunting Titan didn’t preserve a challenge to the Precedential Opinion 

Panel’s (“POP”) application of its standard for when it is 

(and isn’t) appropriate for the Board to sua sponte raise 

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2 HUNTING TITAN, INC. v. DYNAENERGETICS EUROPE GMBH

patentability issues as to new claims.1 I write separately 

to explain why, had that challenge been preserved, it likely 

would have succeeded—and why I’m troubled by how the

PTO is handling this issue, including with a recently enacted regulation.

I

In evaluating new (i.e., proposed substitute or 

amended) claims, “the Board should not be constrained to 

arguments and theories raised by the petitioner in its petition or opposition to the motion to amend.” Nike, Inc. v. 

Adidas AG, 955 F.3d 45, 51 (Fed. Cir. 2020) (emphasis 

added). We’ve reasoned:

It makes little sense to limit the Board, in its role 

within the agency responsible for issuing patents, 

to the petitioner’s arguments in this context. Rather, based on consideration of the entire record, 

the Board must determine whether the patent 

owner’s newly-presented, narrower claims are . . . 

“unpatentable in the face of the prior art cited in 

the IPR.”

Id. at 51–52 (emphasis added) (quoting Aqua Prods., Inc. 

v. Matal, 872 F.3d 1290, 1314 (Fed. Cir. 2017) (en banc) 

(plurality opinion)). Although we haven’t delineated the 

outer bounds of any independent Board duty to ensure that 

new patent claims are, in fact, patentable before they issue, 

we have observed that “the text, structure, and history of 

the IPR [s]tatutes . . . indicate Congress’s unambiguous 

1 This preservation failure was discussed extensively at oral argument, during which Hunting Titan’s 

counsel could not—despite repeated opportunities—identify where its opening brief made this challenge. See Oral 

Arg. at 2:31–4:49, 5:59–7:28, 11:58–15:04, 1:03:27–1:07:37, 

No. 20-2163, https://oralarguments.cafc.uscourts.gov/default.aspx?fl=20-2163_11012021.mp3.

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HUNTING TITAN, INC. v. DYNAENERGETICS EUROPE GMBH 3

intent to permit the [Board] to review [new] claims more 

broadly than” original claims. Uniloc 2017 LLC v. Hulu, 

LLC, 966 F.3d 1295, 1304 (Fed. Cir. 2020); id. at 1306 (noting the absence of “any other context under Title 35—e.g., 

original applications, reexaminations, reissue, etc.—in 

which the [PTO] is required or authorized to newly issue a 

patent claim without ever having determined that the particular claim meets the statutory requirements for patentability”).

The POP nevertheless constrained the Board’s ability 

to raise its own patentability issues as to new claims. It

identified just three situations in which the Board could do 

so: (1) where the petitioner has ceased participating in the 

proceeding altogether; (2) where the petitioner chooses not 

to oppose the patent owner’s motion to amend; and 

(3) where, although the petitioner has opposed, it has failed 

to raise unpatentability evidence that is nonetheless “readily identifiable and persuasive.” Hunting Titan, Inc. v. 

DynaEnergetics Eur. GmbH, IPR2018-00600, 2020 WL 

3669653, at *6 (P.T.A.B. July 6, 2020). The third situation—“readily identifiable and persuasive” evidence—is at 

issue here, given that Hunting Titan opposed DynaEnergetics’s motion to amend.

Whatever the “readily identifiable and persuasive”

standard means, it should have let the Board do what it did 

here: evaluate whether the prior-art reference that anticipated the original claims also anticipated the new claims. 

Such an evaluation can hardly be deemed overly zealous or 

creative on the Board’s part. Indeed, among potential unpatentability bases to raise sua sponte, this would seem to 

be square one. But the POP disagreed. It forbade the 

Board from making that basic evaluation. The POP thus 

denied three administrative patent judges—who had devoted extensive resources to analyzing this prior-art reference—the ability to use that acquired expertise in making 

their own patentability determinations before letting new 

claims out the door. I don’t see how the POP’s decision in 

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4 HUNTING TITAN, INC. v. DYNAENERGETICS EUROPE GMBH

this regard is reasonable. It also appears inconsistent with 

Nike, where we approved the Board’s sua sponte unpatentability finding based on a prior-art reference not even mentioned in the petitioner’s opposition.2 See Nike, 955 F.3d 

at 48–53.

But, because Hunting Titan forfeited a challenge to the 

POP’s application of its new standard here, review of that

standard’s application must await another day.

II

The POP stressed the adversarial aspect of IPRs when

justifying its “readily identifiable and persuasive” constraint on the Board. Hunting Titan, 2020 WL 3669653, 

at *5–6, *9. But it acknowledged that motions to amend

don’t always have an adversary. For example, the petitioner might have dropped out or declined to oppose. Accordingly, the POP framed the “readily identifiable and 

persuasive” constraint as applying only to situations where 

the petitioner opposes a motion to amend:

To be sure, there may be circumstances where the 

adversarial system fails to provide the Board with 

potential arguments for the unpatentability of the 

proposed substitute claims. As noted above, the 

Supreme Court in Cuozzo specifically addressed

one such situation, in which the petitioner has 

ceased to participate in the proceeding altogether. 

A similar situation may exist where a petitioner 

chooses not to oppose the motion to amend. And 

2 Here, Hunting Titan cited and discussed the 

Schacherer reference throughout its opposition to 

DynaEnergetics’s motion to amend. J.A. 518–47. But it 

argued obviousness (not anticipation), and as to one of the 

newly added claim elements, the Board found a disclosure 

in Schacherer that Hunting Titan’s opposition did not specifically identify.

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HUNTING TITAN, INC. v. DYNAENERGETICS EUROPE GMBH 5

even where both a petitioner and patent owner participate in the motion to amend process, there may 

be situations where certain evidence of unpatentability has not been raised by the petitioner, but is 

readily identifiable and persuasive such that the 

Board should take it up in the interest of supporting the integrity of the patent system, notwithstanding the adversarial nature of the proceedings.

Id. at *6 (emphasis added) (citation omitted).3 The clear 

implication was that the Board would not be so constrained 

when a motion to amend is unopposed. Id.; see Nike, 

955 F.3d at 51 (expressing concern over limiting the PTO’s 

“ability to examine the new claims” in cases where the petitioner has not opposed).

The PTO, however, has since enacted a regulation that 

seemingly applies the “readily identifiable and persuasive” 

constraint to all motions to amend—opposed or not. The 

following provision now applies4:

(d) Burden of Persuasion. On a motion to amend:

(1) A patent owner bears the burden of persuasion to show, by a preponderance of the 

evidence, that the motion to amend complies with the requirements of paragraphs 

(1) and (3) of 35 U.S.C. § 316(d), as well as 

3 The PTO’s brief in this appeal adopted this same 

framing. E.g., Intervenor’s Br. 17 (“These circumstances 

include where the petitioner ceases to participate in the 

proceeding altogether or does not oppose the motion to 

amend; and, even when the petitioner opposes, where the evidence of unpatentability is readily identifiable and persuasive . . . .” (emphasis added)).

4 This provision applies to all motions to amend filed 

on or after January 20, 2021, so it doesn’t apply in this case.

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6 HUNTING TITAN, INC. v. DYNAENERGETICS EUROPE GMBH

paragraphs (a)(2), (a)(3), (b)(1), and (b)(2) of 

this section;

(2) A petitioner bears the burden of persuasion to show, by a preponderance of the evidence, that any proposed substitute claims 

are unpatentable; and

(3) Irrespective of paragraphs (d)(1) and (2) 

of this section, the Board may, in the interests of justice, exercise its discretion to 

grant or deny a motion to amend only for 

reasons supported by readily identifiable 

and persuasive evidence of record. In doing 

so, the Board may make of record only 

readily identifiable and persuasive evidence in a related proceeding before the 

[PTO] or evidence that a district court can 

judicially notice. Where the Board exercises its discretion under this paragraph, 

the parties will have an opportunity to respond.

37 C.F.R. § 42.121(d) (emphasis added); see Rules of Practice to Allocate the Burden of Persuasion on Motions to 

Amend in Trial Proceedings Before the Patent Trial and 

Appeal Board, 85 Fed. Reg. 82,923, 82,924 (Dec. 21, 2020) 

(setting forth the effective date).

The PTO’s remarks accompanying this regulation’s enactment note some situations where the “readily identifiable and persuasive” constraint would apply. For example, 

if the patent owner’s briefing fails to expressly address or

establish every statutory and regulatory requirement for a 

motion to amend (as 37 C.F.R. § 42.121(d)(1) mandates), 

the Board may nonetheless determine that such requirements are met—but “only when there is readily identifiable 

and persuasive evidence” showing as much. 85 Fed. Reg. 

at 82,927. Likewise, where a petitioner opposes a motion 

to amend “but fails to raise certain evidence of 

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HUNTING TITAN, INC. v. DYNAENERGETICS EUROPE GMBH 7

unpatentability that is [nonetheless] readily identifiable 

and persuasive,” the Board may take up that evidence, 

“notwithstanding the adversarial nature of the proceedings.” Id.

The prospect of applying the “readily identifiable and 

persuasive” constraint to unopposed motions to amend, 

however, is what particularly troubles me. Although the 

POP indicated that the constraint wouldn’t apply in such 

circumstances, see Hunting Titan, 2020 WL 3669653, at *6, 

and although the PTO maintains that this regulation “codifie[s]” or “embod[ies] the policy determination articulated 

by the POP here,” Intervenor’s Br. 17–18, 29–30, the regulation appears to apply the constraint to all motions to 

amend—opposed or not. Indeed, the PTO’s counsel at oral 

argument adopted that view, maintaining that the regulation imposes the “readily identifiable and persuasive” constraint even in unopposed situations. Oral Arg. at 

21:03–13; see id. at 19:39–59. According to counsel, the 

reason for doing so is “to encourage the parties to remain 

in and oppose the motion [to amend].” Oral Arg. at 

19:48–57. But an adverse petitioner needs no extra encouragement to oppose a motion. And if the petitioner is no 

longer adverse—e.g., having settled or satisfied itself that 

an amendment removes the threat of infringement—it’s 

unclear how the PTO’s policy would affect the petitioner’s 

incentive to oppose.

Because the regulation makes no caveat for unopposed 

motions, the Board may find its hands tied (or its head 

forced into the sand) even when no one is around to oppose 

a new patent monopoly grant.

* * *

The “basic purpose[]” of IPRs is “to reexamine an earlier agency decision,” thus “help[ing] protect the public’s 

paramount interest in seeing that patent monopolies are 

kept within their legitimate scope.” Cuozzo Speed Techs., 

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8 HUNTING TITAN, INC. v. DYNAENERGETICS EUROPE GMBH

LLC v. Lee, 579 U.S. 261, 279–80 (2016) (cleaned up). That 

purpose is particularly salient here, given that the Board 

usually evaluates the patentability of new claims only after

it has recognized the PTO’s original error in issuing unpatentable claims. I don’t see the reasonableness of a policy that seriously hinders the Board’s basic efforts to avoid 

making the same error twice.

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