United States Court of Appeals 

for the Federal Circuit ______________________

NETWORK-1 TECHNOLOGIES, INC.,

Plaintiff-Appellant

v.

HEWLETT-PACKARD COMPANY, HEWLETT 

PACKARD ENTERPRISE COMPANY,

Defendants-Cross-Appellants

______________________

2018-2338, 2018-2339, 2018-2395, 2018-2396

______________________

Appeals from the United States District Court for the 

Eastern District of Texas in Nos. 6:11-cv-00492-RWS, 6:13-

cv-00072-RWS, Judge Robert Schroeder, III.

______________________

OPINION ISSUED: September 24, 2020

OPINION MODIFIED: November 20, 2020*

______________________

GREGORY S. DOVEL, Dovel & Luner, LLP, Santa Monica, CA, argued for plaintiff-appellant. Also represented by 

SEAN LUNER, RICHARD ELGAR LYON, III; JEFFREY A.

LAMKEN, MoloLamken LLP, Washington, DC. 

 MARK ANDREW PERRY, Gibson, Dunn & Crutcher LLP, 

* This opinion has been modified and reissued following a petition for panel rehearing filed by Appellant.

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Washington, DC, argued for defendants-cross-appellants. 

Also represented by OMAR FAROOQ AMIN; HERSH H. MEHTA, 

Morgan, Lewis & Bockius LLP, Chicago, IL; NATALIE A.

BENNETT, Washington, DC. 

 ANDREW M. MASON, Klarquist Sparkman, LLP, Portland, OR, for amicus curiae T-Mobile USA, Inc. Also represented by SARAH ELISABETH JELSEMA, JOHN D.

VANDENBERG; SARAH J. KALEMERIS, Winston & Strawn 

LLP, Chicago, IL. 

______________________

Before PROST, Chief Judge, NEWMAN and BRYSON,

Circuit Judges.

PROST, Chief Judge.

Network-1 Technologies, Inc. (“Network-1”) appeals a 

final judgment of the United States District Court for the 

Eastern District of Texas. Network-1 sued Hewlett-Packard (“HP”), alleging infringement of U.S. Patent 

No. 6,218,930 (“the ’930 patent”). HP argued in response 

that the ’930 patent is invalid, and that HP did not infringe. The jury found the patent not infringed and invalid. 

Following post-trial motions, the district court denied Network-1’s request for a new trial on infringement but 

granted Network-1’s motion for judgment as a matter of 

law (“JMOL”) on validity. 

Network-1 appeals the district court’s final judgment 

that HP does not infringe the ’930 patent, arguing the district court erred in its claim construction. HP cross-appeals the district court’s determination that HP was 

estopped from raising certain validity challenges under 

35 U.S.C. § 315(e)(2) based on HP’s joinder to an inter 

partes review (“IPR”) before the Patent Trial and Appeal 

Board (“Board”). On cross-appeal, HP also argues that 

Network-1 improperly broadened claim 6 of the ’930 patent

during reexamination.

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For the reasons explained below, we affirm-in-part, reverse-in-part, vacate, and remand. Specifically, as to Network-1’s appeal, we affirm-in-part and reverse-in-part the 

district court’s claim construction and remand to the district court. As to HP’s cross-appeal, we vacate the district 

court’s JMOL on validity and remand. And finally, we affirm the district court’s decision with respect to improper 

claim broadening.

FACTUAL BACKGROUND

I. The ’930 Patent

The ’930 patent is titled “Apparatus and Method for Remotely Powering Access Equipment over a 10/100 Switched 

Ethernet Network.” It discloses an apparatus and methods

for allowing electronic devices to automatically determine 

if remote equipment is capable of accepting remote power 

over Ethernet. See ’930 patent col. 1 ll. 13–17. According 

to the patented method, a “low level current” is delivered 

over a data signaling pair to an access device (also called 

remote equipment or remote access equipment). Id. at 

col. 2 ll. 8–10. After the low level current is sent, a network 

switch senses the resulting “voltage level” on the data signaling pair. Id. at col. 1 l. 65–col. 2 l. 14. If the device can 

accept remote power, the sensed voltage level will match a 

“preselected condition” of the voltage, such as a particular 

“varying voltage” level. Id. at col. 2 ll. 10–14, col. 3 ll. 2–

17. Upon detecting the preselected condition, the network 

switch will increase the current from the low level to a 

higher level sufficient to allow the “remote equipment [to] 

become[] active.” Id. at col. 3 ll. 17–22. If the preselected 

condition of the voltage is not detected, the network switch 

will determine that the device cannot accept remote power

and will not transmit a higher current. Id. at col. 3 ll. 3–

11.

The ’930 patent issued in April 2001 with 9 claims, including two independent claims: claims 1 and 6. Claim 6 

is representative of the issues on appeal. Claim 6 recites: 

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6. Method for remotely powering access equipment 

in a data network, comprising,

providing a data node adapted for data switching, 

an access device adapted for data transmission, at 

least one data signaling pair connected between 

the data node and the access device and arranged 

to transmit data therebetween, a main power 

source connected to supply power to the data node, 

and a secondary power source arranged to supply 

power from the data node via said data signaling 

pair to the access device,

delivering a low level current from said main 

power source to the access device over said data signaling pair,

sensing a voltage level on the data signaling pair in 

response to the low level current, and

controlling power supplied by said secondary 

power source to said access device in response to 

a preselected condition of said voltage level.

’930 patent claim 6 (emphases added to terms challenged 

on appeal). 

On appeal, Network-1 contends that the district court 

erroneously construed the claim terms “main power 

source” and “low level current.” On cross-appeal, HP contends that Network-1 improperly broadened the term “secondary power source” during reexamination.

II. The Reexamination Proceedings

After it issued, and concurrent with the underlying district court action, the ’930 patent was reexamined twice before the U.S. Patent and Trademark Office. The first

reexamination, No. 90/012,401 (“the ’401 reexamination”), 

concluded in October 2014. See J.A. 333–35. It confirmed 

the patentability of claims 6, 8, and 9, and resulted in the 

issuance of claims 10–23. Relevant to HP’s cross-appeal, 

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claims 15 and 16 were added depending from original 

claim 6.

Claim 15 recites: “Method according to claim 6, 

wherein said secondary power source is the same source 

of power as said main power source.” ’930 patent, Ex Parte 

Reexamination Certificate, col. 1 ll. 39–41 (emphasis 

added).

Claim 16 recites: “Method according to claim 6, 

wherein said secondary power source is the same physical device as the main power source.” Id. at col. 1 ll. 42–44 

(emphasis added).

The second reexamination, No. 90/013,444, concluded 

in November 2015. It confirmed the patentability of claims 

6 and 8–23. See J.A. 336–37.

PROCEDURAL BACKGROUND

This case has a long and complicated history, which began in 2011 when Network-1 sued a number of defendants, 

including HP, for infringement of the ’930 patent in the 

U.S. District Court for the Eastern District of Texas. After 

several stays, the district court finally reached the underlying final judgment in 2018. We discuss the relevant 

background here. 

I. The Avaya IPR

After Network-1 filed its complaint in the district court, 

another defendant, Avaya Inc. (“Avaya”), petitioned for 

IPR of the ’930 patent. The district court stayed its proceedings pending IPR. The Board partially instituted 

Avaya’s petition. See Avaya Inc. v. Network-1 Sec. Sols., 

Inc., No. IPR2013-00071, Paper 18, 2013 WL 8595554 

(P.T.A.B. May 24, 2013) (“the Avaya IPR”). Specifically, 

the Board instituted review of claims 6 and 9 of the ’930 

patent based on two grounds: (1) anticipation under 

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35 U.S.C. § 102(b) by Matsuno1; and (2) obviousness under 

35 U.S.C. § 103(a) by De Nicolo2 and Matsuno. Id. at *16.

Following institution, HP, together with other petitioners, filed an IPR petition and motion to join the Avaya IPR. 

HP’s petition included grounds different from those that 

had already been instituted. The Board denied HP’s request. HP, with others, thereafter filed a second IPR petition and motion to join the Avaya IPR, this time including 

only the grounds already instituted. The Board granted 

HP’s request, and HP was joined as a party to the Avaya 

IPR. At the time that HP filed its second IPR petition, 

more than one year had passed since the district court complaint had been served, and therefore, HP was time-barred 

under 35 U.S.C. § 315(b) from having its own petition instituted. But because § 315(b) creates an exception from 

the time bar for joinder under 35 U.S.C. § 315(c), HP was 

nonetheless able to join.

In its final written decision, the Board held that neither claim 6 nor claim 9 was unpatentable over the instituted grounds. We affirmed. See Avaya Inc. v. Network-1 

Techs., Inc., 612 F. App’x 613 (Fed. Cir. 2015). 

II. The District Court Action

After more stays, Network-1 continued its suit in the 

district court. In 2017, the district court issued its construction of disputed claim terms, including “low level current” and “main power source.” See Network-1 Techs., Inc. 

v. Alcatel-Lucent USA, Inc., ET, No. 6:11-cv-492, Report 

and Recommendation of the Magistrate Judge, D.I. 693, 

at 12 (E.D. Tex. Nov. 4, 2016) (J.A. 24–48); see also Network-1 Techs., Inc. v. Alcatel-Lucent USA, Inc., ET, No. 

1 Japanese Unexamined Patent Application Publication No. H10-13576, published Jan. 16, 1998 (“Matsuno”).

2 U.S. Patent No. 6,115,468, filed Mar. 26, 1998,

issued Sept. 5, 2000 (“De Nicolo”).

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6:11-cv-492, Order Adopting Report and Recommendation 

of U.S. Magistrate Judge, D.I. 860, at 1, 5–7 (E.D. Tex. 

May 2, 2017) (J.A. 49–68). Together with its claim construction, in relevant part, the district court denied HP’s 

summary judgment motion that argued claim 6 was impermissibly broadened through the ’401 reexamination. 

J.A. 40–42, 57–59. 

This case finally proceeded to trial in November 2017. 

At trial, Network-1 argued that HP infringed claims 6, 13, 

14, 17, 20, and 22 of the ’930 patent (“the asserted claims”)

by selling particular Power over Ethernet (“PoE”) switches.

HP argued that each of the asserted claims was rendered 

obvious by both public use of “the Fisher system,” which 

was a PoE system developed by David Fisher, and by the 

patents and printed publications referred to as “the Fisher 

patents,”3 Woodmas,4 and Chang.5 See J.A. 78.

Using a general verdict form, the jury found that HP 

did not infringe any asserted claim of the ’930 patent. 

J.A. 70. The jury also found that HP had shown that all 

asserted claims of the ’930 patent are invalid. J.A. 71. 

Following the jury’s verdict, Network-1 filed, in relevant part, a motion for a new trial related to infringement,

and a motion for JMOL and motion for a new trial related 

3 U.S. Patent No. 5,994,998, filed May 29, 1997, issued Nov. 20, 1999; U.S. Patent No. 6,710,704, filed Oct. 

28, 2002, issued Mar. 23, 2004; International Publication 

No. WO 98/54843, published Dec. 3, 1998 (collectively, “the 

Fisher patents”).

4 U.S. Patent No. 5,345,592, filed Apr. 8, 1992, issued Sept. 6, 1994 (“Woodmas”).

5 U.S. Patent No. 5,991,885, filed June 11, 1997, issued Nov. 23, 1999; International Publication 

No. WO 98/57248, published Dec. 17, 1998 (collectively,

“Chang”).

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to validity. The district court denied the motion for a new 

trial on infringement. Applying its construction of the 

claim terms “low level current” and “main power source,”

the district court concluded that the jury’s verdict was not 

against the great weight of the evidence that HP’s accused 

devices did not meet either limitation. See J.A. 92–97.

As to the ’930 patent’s validity, however, the district 

court granted Network-1’s motion for JMOL. The district 

court concluded that because of HP’s joinder to the Avaya 

IPR, HP should have been estopped under 35 U.S.C. 

§ 315(e) from raising the remaining obviousness challenges, which it determined “reasonably could have been 

raised” in the Avaya IPR. J.A. 91.6 The district court did 

not conditionally rule on HP’s motion for a new trial with 

respect to validity.

Network-1 appealed. HP cross-appealed. We have jurisdiction under 28 U.S.C. § 1295(a)(1).

DISCUSSION

On appeal, Network-1 challenges the district court’s 

denial of a new trial on infringement based on its argument 

that the district court erred in its claim construction. 

On cross-appeal, HP challenges the district court’s 

JMOL on validity, arguing that the district court erred in 

concluding that HP is estopped from raising its obviousness challenges because it joined the Avaya IPR. HP further challenges the district court’s denial of summary 

6 With respect to the Fisher system, the district 

court concluded that HP failed to show that the Fisher system constitutes prior art. See J.A. 79–87. On cross-appeal, 

HP does not challenge the district court’s conclusion that 

the Fisher system does not constitute prior art. Appellee’s 

Br. 62 n.2. 

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judgment, arguing that the asserted claims of the ’930 patent were improperly broadened during reexamination. 

We address these issues in turn.

I. Claim Construction

Network-1 argues that the district court incorrectly 

construed the claim terms “low level current” and “main 

power source,” and that this error entitles it to a new trial 

on infringement. HP argues in response that the district 

court’s claim construction should be affirmed, but that even 

if it is not, Network-1 was not prejudiced by the erroneous 

claim construction.

For the below-described reasons, we conclude that the 

district court correctly construed “low level current” but 

erred in its construction of “main power source,” and as a 

result of that error, Network-1 is entitled to a new trial on 

infringement. We therefore vacate the district court’s judgment of non-infringement and remand for a new trial to 

determine whether HP infringes the asserted claims based 

on the correct construction of “main power source.” 

A

We review the district court’s ultimate construction of 

the claim language de novo. Teva Pharms. USA, Inc. v. 

Sandoz, Inc., 574 U.S. 318, 331 (2015). “[W]hen the district 

court reviews only evidence intrinsic to the patent (the patent claims and specifications, along with the patent’s prosecution history), the judge’s determination will amount 

solely to a determination of law, and [we] will review that 

construction de novo.” Id. To the extent that subsidiary 

factfinding is required for claim construction analysis, we 

review such factfinding for clear error. Id. at 332. 

Claim terms “are generally given their ordinary and 

customary meaning,” which is “the meaning that the term 

would have to a person of ordinary skill in the art in question at the time of the invention.” Phillips v. AWH Corp., 

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415 F.3d 1303, 1312–13 (Fed. Cir. 2005) (en banc) (internal 

quotation marks and citations omitted). “[T]he claims 

themselves provide substantial guidance as to the meaning 

of particular claim terms” and “the specification is the single best guide to the meaning of a disputed term.” Id. 

at 1314–15 (internal quotation marks and citations omitted). 

As the party seeking to disturb the non-infringement 

judgment, Network-1 “must establish that [the challenged 

jury] instructions were legally erroneous, and that the errors had prejudicial effect.” SSL Servs., LLC v. Citrix Sys., 

769 F.3d 1073, 1085 (Fed. Cir. 2014) (quoting Ecolab Inc. 

v. Paraclipse, Inc., 285 F.3d 1362, 1373 (Fed. Cir. 2002)). 

“It is well established that when an incorrect jury instruction—such as an incorrect claim construction—removes from the jury a basis on which the jury could 

reasonably have reached a different verdict, the verdict 

should not stand.” Cardiac Pacemakers, Inc. v. St. Jude 

Med., Inc., 381 F.3d 1371, 1383 (Fed. Cir. 2004); see also 

Avid Tech., Inc. v. Harmonic, Inc., 812 F.3d 1040, 1042 

(Fed. Cir. 2016). An erroneous claim construction on one 

element is harmless “only if a reasonable jury would have 

been required by the evidence to find non-infringement 

even without the error.” Avid, 812 F.3d at 1047.

B

The district court construed “low level current” as “a 

non-data-signal current that is sufficient to begin start up 

of the access device but that is not sufficient to sustain the 

start up.” J.A. 35; see also J.A. 53–55. The district court 

explained that it was construing the disputed phrase to 

give meaning to the constituent term “low.” See J.A. 34. It 

stated that while the current must be sufficient to “begin 

start up,” the current need not “cause start up,” and thus 

it construed the term to eliminate “any implication that the 

current must be sufficient to result in a completed startup.” J.A. 34 (citing ’930 patent col. 3 ll. 12–17). 

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On appeal, Network-1 argues that the district court 

erred by construing the phrase “low level current” to have 

a lower bound. Network-1 agrees that, in the context of the 

’930 patent, the phrase “low level current” describes current that cannot “sustain start up” but argues that it was 

error for the district court to additionally require that the 

current be sufficient to begin start up. See Appellant’s 

Br. 27. Relying on extrinsic evidence related to the word 

“low,” including dictionary definitions, grammar references, and claim constructions adopted for unrelated patents, Network-1 argues that the term points in one 

direction and should be construed to have a single reference point. Network-1 asserts that the correct reference 

point with respect to the ’930 patent is the upper boundary 

requiring that the current not exceed the level needed to 

operate the device. We disagree.

We conclude that the district court correctly construed 

“low level current.” As an initial matter, there is no dispute 

that the word “low” in the claim phrase “low level current” 

operates to limit the upper boundary of the current level. 

See Appellant’s Br. 26–29; Appellee’s Br. 36–37. Indeed, 

the ’930 patent explicitly describes a low level current with 

an upper boundary that is “unable to sustain start up.” See

’930 patent col. 3 ll. 14–16; see also id. at col. 3 ll. 2–13. But

the claim phrase is not limited to the word “low,” and the 

claim construction analysis should not end just because one 

reference point has been identified. To be sure, the claim 

phrase “low level current” does not preclude a lower bound 

by use of the word “low.” Rather, in the same way the 

phrase should be construed to give meaning to the term 

“low,” the phrase must also be construed to give meaning 

to the term “current.” 

The intrinsic record of the ’930 patent confirms that the 

district court correctly construed the phrase to require a 

lower boundary of current. See Phillips, 415 F.3d at 1315. 

Claim 6 recites “delivering a low level current” to an access 

device to detect whether the device can accept remote 

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power. ’930 patent col. 4 ll. 49–67 (emphasis added); see 

also id. at col. 2 ll. 8–14. The express language of the claim 

thus requires that at least some level of current be delivered. Even Network-1 admits that the term “current” necessarily requires some flow of electric charge because “[i]f 

there is no flow, there is no ‘current.’” See Appellant’s Br. 

33–34.

The specification of the ’930 patent discloses the lower 

boundary of current. It explains that an access device capable of accepting remote power will signal a varying voltage level and teaches “[t]he varying level is created by the 

remote power supply beginning to start up but the low current level is unable to sustain the start up.” ’930 patent 

col. 3 ll. 14–16 (emphasis added); see also id. at col. 3 ll. 2–

13. Thus, consistent with the district court’s construction, 

the ’930 patent teaches that the delivered “low level current” is current that is sufficient to begin start-up. 

Accordingly, we conclude that the district court did not 

err in its construction of “low level current.”

C

The district court construed “main power source” as “a 

DC power source,” and thereby excluded AC power sources 

from its construction. J.A. 50–51.7 In reaching its decision,

the court relied on HP’s expert testimony that a network 

device would either fail to function or would be damaged if 

it received AC power. J.A. 50–51. The court therefore concluded that embodiments using AC power are inoperable 

and construed “main power source” to exclude such embodiments. J.A. 50–51 (“A construction that renders the 

claimed invention inoperable should be viewed with extreme skepticism.” (quoting Talbert Fuel Sys. Pats. Co. v. 

7 “DC” refers to direct current and “AC” refers to alternating current.

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Unocal Corp., 275 F.3d 1371, 1376 (Fed. Cir. 2002))); see 

also J.A. 30–31. 

On appeal, Network-1 argues that the claim phrase

“main power source” should be construed consistent with

the ordinary meaning of “power source” to include both AC 

and DC power sources. See Appellant’s Br. 46. Network-1 

acknowledges that certain embodiments with AC power 

sources require power from the main power source to be 

converted to DC power before being received by the network device, but Network-1 argues that nothing in the 

’930 patent precludes such embodiments. To the contrary, 

Network-1 asserts that the intrinsic record supports a construction that includes both types of power sources. We 

agree and reverse the district court’s construction of main 

power source. 

We conclude that the correct construction of “main 

power source” includes both AC and DC power sources. 

There is no dispute that the ordinary meaning of “power 

source” includes both AC and DC power sources. Appellant’s Br. 45–49; see Appellee’s Br. 47. And neither the 

claims nor the specification of the ’930 patent require a departure from this ordinary meaning. Starhome GmbH v.

AT & T Mobility LLC, 743 F.3d 849, 857 (Fed. Cir. 2014)

(“In the absence of an express intent to impart a novel 

meaning to claim terms, an inventor’s claim terms take on 

their ordinary meaning.”). 

Claim 6 recites a “main power source” that is “connected to supply power to the data node” and that “deliver[s] a low level current . . . to the access device.” 

’930 patent col. 4 ll. 56–57, ll. 60–61; see also id. at col. 1 

ll. 64–65, col. 2 ll. 8–9. Nowhere do the claims suggest that 

the “main power source” should be limited to DC power 

sources. 

The specification likewise never expresses a preference 

for DC power sources, much less a suggestion that DC 

power is an “essential” feature of the main power source. 

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See GE Lighting Sols., LLC v. AgiLight, Inc., 750 F.3d 

1304, 1309–10 (Fed. Cir. 2014). Indeed, far from limiting 

the plain language of the claims to a DC power source, the 

specification states that the power source may be a “conventional main power supply,” which according to the ordinary meaning would include both AC and DC power 

sources. ’930 patent col. 2 ll. 52–53. This reading of the 

specification is further confirmed by the ’930 patent’s disclosure of a preferred embodiment, which is shown in Figures 1 and 3. See MBO Labs., Inc. v. Becton, Dickinson & 

Co., 474 F.3d 1323, 1333 (Fed. Cir. 2007) (“A claim interpretation that excludes a preferred embodiment from the 

scope of the claim is rarely, if ever, correct.” (internal citation omitted)). In Figure 1, power source 16 is identified as 

a “conventional” power supply, and in Figure 3, main power 

supply 70 is specifically depicted as a traditional AC power 

outlet. ’930 patent col. 2 ll. 52–53, Fig. 3.

Despite the express disclosures of the ’930 patent, the 

district court construed “main power source” to exclude AC 

power sources on the basis of expert testimony that receipt 

of AC power by a network device would render it inoperable. J.A. 30–31, 50–51. This is error for two reasons. First, 

even though the network device cannot receive AC power, 

the record establishes that “data nodes” or network 

switches were commonly used to convert AC power to DC 

power as needed to power the network device. Indeed, we 

need not look beyond the specification of the ’930 patent. 

In the preferred embodiment, as shown in Figure 1, a data 

node exists between main power source 16 and the remote 

equipment. And in Figure 3, an 8-port switch is shown connected to the AC power outlet such that the AC power is 

converted to DC power before reaching the network device. 

’930 patent col. 2 l. 29, col. 3 ll. 59–60, Figs. 1 & 3. Even 

HP’s expert Dr. Neikirk explained that Figure 3 illustrates 

“‘the main power supply 70’ receiving power from a typical 

AC wall socket, and in turn suppl[ying] operational power 

via the ‘Main Power Distribution Bus’ to the data 

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switches.” J.A. 1049 ¶ 35. Nothing in the claims of the 

’930 patent precludes the conversion of AC power to DC 

power, and it was error for the district court to add such a 

limitation.

Second, the district court erred by adding a limitation 

to the claims to carve out certain inoperable embodiments. 

To be sure, we have stated that we skeptically view a construction that renders all embodiments inoperable, but we 

have instructed that it is nonetheless improper to add limitations to constructions to exclude only certain inoperable 

embodiments. Cordis Corp. v. Medtronic AVE, Inc., 

511 F.3d 1157, 1174 (Fed. Cir. 2008). In this case, the district court’s construction not only excluded inoperable embodiments that do not convert AC to DC power, but also 

excluded operable embodiments, like the preferred embodiment. See MBO Labs., 474 F.3d at 1333.

Accordingly, we conclude that the district court erred 

in its construction of “main power source.” 

D

We now consider the effect of the district court’s erroneous construction of “main power source” on the jury’s verdict of non-infringement. Network-1 argues that if the 

district court erred in its construction of either claim term, 

that error was prejudicial, and it is entitled to a new trial 

on infringement. HP argues in response that to the extent 

either term was misconstrued, such error was harmless

and the judgment of non-infringement should not be disturbed. We conclude that Network-1 established that it

was prejudiced by the district court’s erroneous claim construction of “main power source” and is entitled to a new 

trial on infringement.

At trial, HP contested infringement based on the elements “low level current” and “main power source.” With 

respect to “main power source,” the record shows that the 

jury was instructed to apply the erroneous construction, 

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that Network-1 elicited testimony showing that the main 

power source for certain HP products originates at an AC 

input, J.A. 2291, 2056, and that HP relied on evidence of 

non-infringement, at least in part, based on the fact that 

these products are not within the scope of the ’930 patent

because they use an AC input, J.A. 2056–57, 2065–66. The 

jury found that HP did not infringe the asserted claims of 

the ’930 patent. Because the general verdict form does not 

indicate the basis for the jury’s decision, where the evidence shows that HP relied on the district court’s erroneous 

construction for its argument that it does not infringe the 

asserted claims, we conclude that Network-1 has established that it was prejudiced by the claim construction. 

J.A. 69–70. 

HP argues that the erroneous claim construction was 

harmless because HP presented conclusive evidence that 

no accused product meets the claim limitation “delivering

a low level current from said main power source.” Appellee’s Br. 25–26 (emphases in original). More particularly, 

HP argues that the record shows that its products deliver 

detection current from a PoE chip, not an AC or DC power 

source. But HP’s argument relies on an element that is not 

in the claims—namely, that current be delivered directly

from the main power source to the access device. Indeed, 

the district court expressly rejected HP’s attempt to import

such a limitation during claim construction. See J.A 39–40. 

And in any case, Network-1 presented evidence at trial 

showing that HP’s products practice this claim limitation. 

See, e.g., J.A. 1790–95, 2480–81, 2724. We therefore reject 

HP’s argument that the non-infringement verdict may be 

affirmed on appeal.

Accordingly, we affirm the district court’s construction 

of “low level current,” reverse the district court’s construction of “main power source,” and remand to the district 

court for proceedings consistent with this opinion.

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II. Statutory Estoppel

We now turn to HP’s cross-appeal. HP argues that the 

district court erroneously granted JMOL with respect to 

the ’930 patent’s validity based on its determination that 

HP was estopped under 35 U.S.C. § 315(e) from presenting 

obviousness challenges as a consequence of its joinder to 

the Avaya IPR. We agree that HP is not estopped. We 

therefore vacate the district court’s judgment and remand

to the district court for proceedings consistent with this 

opinion.

A

We review “decisions on motions for JMOL, motions for 

a new trial, and evidentiary rulings under the law of the 

regional circuit.” SSL Servs., 769 F.3d at 1082. The Fifth 

Circuit reviews decisions on motions for JMOL “de novo, 

reapplying the JMOL standard.” Summit 6, LLC v. Samsung Elecs. Co., 802 F.3d 1283, 1293 (Fed. Cir. 2015) (citing 

Ford v. Cimarron Ins. Co., 230 F.3d 828, 830 (5th Cir. 

2000)). In the Fifth Circuit, a jury verdict may only be reversed by JMOL if substantial evidence does not support 

the verdict. Versata Software, Inc. v. SAP Am., Inc., 

717 F.3d 1255, 1261 (Fed. Cir. 2013). “Thus, a JMOL may 

only be granted when, ‘viewing the evidence in the light 

most favorable to the verdict, the evidence points so 

strongly and overwhelmingly in favor of one party that the 

court believes that reasonable jurors could not arrive at 

any contrary conclusion.’” Id. (quoting Dresser–Rand Co. 

v. Virtual Automation, Inc., 361 F.3d 831, 838 (5th Cir.

2004)).

B

Following trial, the district court granted Network-1’s 

motion for JMOL on validity of the ’930 patent. The district 

court concluded that as a result of HP’s joinder to the 

Avaya IPR, HP was estopped under 35 U.S.C. § 315(e) from 

raising obviousness challenges not based on the Fisher 

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system. J.A. 91. According to the district court, in contrast 

to the Fisher system, which was not a patent or printed 

publication that HP “reasonably could have raised” in the 

IPR, HP could have reasonably raised its remaining invalidity arguments during the IPR—i.e., the Fisher patents, 

Woodmas, and Chang. J.A. 88–89, 91 (quoting 35 U.S.C. 

§ 315(e)(2)). In reaching this conclusion, the district court 

specifically rejected HP’s argument that it could not have 

raised new grounds in the Avaya IPR because it was a 

joined party. The district court stated that “the fact that 

HP sought joinder with Avaya’s IPR does not mean that HP 

could not have reasonably raised different grounds from 

those raised by Avaya.” J.A. 91. The district court further 

stated that allowing HP to raise arguments “that it elected 

not to raise during the IPR would give it a second bite at 

the apple and allow it to reap the benefits of the IPR without the downside of meaningful estoppel.” J.A. 91 (internal 

quotations omitted). The district court therefore granted 

JMOL on validity without considering the merits of HP’s

invalidity arguments. J.A. 91 & n.6. 

HP argues that, in granting Network-1’s motion for 

JMOL on invalidity, the district court misapplied the estoppel provision under 35 U.S.C. § 315(e)(2). Specifically, 

HP argues that no validity ground that it raised at trial 

“reasonably could have [been] raised” through its joinder to 

the Avaya IPR. See J.A. 88–91. We agree with HP. HP’s 

joinder to the Avaya IPR and the estoppel consequences of 

that joinder are governed by the America Invents Act 

(“AIA”), which established IPR proceedings. According to 

the AIA, under 35 U.S.C. § 315(c), HP was permitted to join 

the Avaya IPR “as a party” even though HP was timebarred under § 315(b) from bringing its own petition. But, 

as we held in Facebook, Inc. v. Windy City Innovations, 

LLC, the joinder provision does not permit a joining party 

to bring into the proceeding new grounds that were not already instituted. Facebook, Inc. v. Windy City Innovations, 

LLC, __ F.3d __, No. 18-1400, 2020 WL 5267975, at *9–10

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(Fed. Cir. Sept. 4, 2020). Rather, it may only join the already-instituted proceeding as a party. Id.

Following a final written decision in an IPR, the AIA 

provides for statutory estoppel under 35 U.S.C. § 315(e) to 

limit the invalidity challenges that an IPR petitioner may 

bring in a separate action involving the same patent 

claims. With respect to district court actions, § 315(e)(2) 

states:

CIVIL ACTIONS AND OTHER PROCEEDINGS.—The petitioner in an inter partes review of a claim in a patent under this chapter that results in a final 

written decision under section 318(a) . . . may not 

assert in . . . a civil action arising in whole or in 

part under section 1338 of title 28 . . . that the 

claim is invalid on any ground that the petitioner 

raised or reasonably could have raised during that 

inter partes review.

35 U.S.C. § 315(e)(2) (emphases added). Thus, according to 

the statute, a party is only estopped from challenging 

claims in the final written decision based on grounds that 

it “raised or reasonably could have raised” during the IPR. 

Because a joining party cannot bring with it grounds other 

than those already instituted, that party is not statutorily 

estopped from raising other invalidity grounds. 

In this case, the Board instituted two grounds in the 

Avaya IPR, which challenged claims 6 and 9 of the ’930 patent based on Matsuno and De Nicolo. HP did not timely 

petition for IPR but relied on the joinder exception to the 

time bar under § 315(b). HP first filed a motion to join the 

Avaya IPR with a petition requesting review based on 

grounds not already instituted. The Board correctly denied 

HP’s request. The Board, however, granted HP’s second 

joinder request, which petitioned for only the two grounds 

already instituted. When the Board reached a final written 

decision in the Avaya IPR, because HP was a petitioner in

that proceeding, HP was statutorily estopped from raising 

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invalidity grounds based on Matsuno and De Nicolo 

against claims 6 and 9 in a district court action. HP, however, was not estopped from raising other invalidity challenges against those claims because, as a joining party, HP 

could not have raised with its joinder any additional invalidity challenges. Thus, contrary to the district court’s suggestion, permitting HP to challenge the asserted claims of 

the ’930 patent as obvious over the Fisher patents, Woodmas, and Chang does not give HP a “second bite at the apple” to challenge the ’930 patent, J.A. 91, because HP could 

not have raised such a challenge in the Avaya IPR. 

Accordingly, we conclude that HP was not statutorily 

estopped under § 315(e) from challenging the asserted 

claims of the ’930 patent based on the Fisher patents, 

Woodmas, and Chang, which were not raised in the Avaya 

IPR and which could not have reasonably been raised by 

HP. We therefore vacate the district court’s JMOL decision 

on validity with respect to estoppel.

C

Because we conclude that the district court erred in 

granting JMOL of validity for Network-1 on the basis that 

HP was statutorily estopped from raising certain invalidity 

challenges, we vacate that decision. 

HP argues that if we vacate the district court’s JMOL 

on validity, substantial evidence supports the jury’s verdict 

of invalidity, and thus the jury’s verdict should be reinstated. In response, Network-1 argues that even if we reverse on estoppel, we might affirm the JMOL on 

alternative grounds relating to substantive validity arguments in Network-1’s JMOL motion that the district court 

did not reach. Network-1 also argues that there is an outstanding new-trial motion that must be ruled upon. Indeed, the district court failed to conditionally rule on 

Network-1’s motion for a new trial on validity even though 

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it was required to do so by Federal Rule of Civil Procedure 

50(c). See J.A. 78–91, 9260–65. We will not consider either 

Network-1’s alternative grounds for JMOL or its new-trial 

motion in the first instance. We therefore remand to the 

district court for further proceedings consistent with this 

opinion, which include ruling in the first instance on Network-1’s entitlement to JMOL (notwithstanding this 

court’s holding on estoppel) and its new-trial motion.

III. Claim Broadening

On cross-appeal, HP also argues that claim 6 and the 

other asserted claims are invalid under 35 U.S.C. § 305 because Network-1 improperly broadened claim 6 through 

the addition of claim 15 and 16 in the ’401 reexamination. 

We disagree and affirm the district court’s judgment that 

the asserted claims were not improperly broadened.

A

A patentee is not permitted to enlarge the scope of a 

patent claim during reexamination. 35 U.S.C. § 305. The 

broadening inquiry under § 305 involves two steps: (1) “analyz[ing] the scope of the claim prior to reexamination” and 

(2) “compar[ing] it with the scope of the claim subsequent 

to reexamination.” Creo Prods., Inc. v. Presstek, Inc., 305 

F.3d 1337, 1344 (Fed. Cir. 2002). A claim “is broader in 

scope than the original claims if it contains within its scope 

any conceivable apparatus or process which would not have 

infringed the original patent.” See Predicate Logic, Inc. v. 

Distributive Software, Inc., 544 F.3d 1298, 1303 (Fed. Cir. 

2008). 

“Whether amendments made during reexamination 

enlarge the scope of a claim is a matter of claim construction,” Creo Prods., 305 F.3d at 1344, which we review de 

novo, while giving deference to subsidiary factual determinations, Teva Pharms., 574 U.S. at 331. 

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B

HP argues that dependent claims 15 and 16 added during the ’401 reexamination resulted in improper claim 

broadening of claim 6 and asserted dependent claims. In 

relevant part, prior to reexamination, claim 6 of the 

’930 patent was construed in two separate district court actions to require the “secondary power source” to be physically separate from the “main power source.” See J.A. 59–

62; see also J.A. 40–42. Subsequently, during the ’401 reexamination, Network-1 added claims 15 and 16, which depended from claim 6 and respectively added the limitations

that the secondary power source “is the same source of 

power” and “is the same physical device” as the main power 

source. ’930 patent, Ex Parte Reexamination Certificate,

col. 1 ll. 39–44. 

After claims 15 and 16 issued at the conclusion of the 

’401 reexamination, HP moved in the underlying district 

court action for summary judgment of invalidity under 

35 U.S.C. § 305 for improper claim broadening. Network-1 

subsequently filed a statutory disclaimer under 35 U.S.C. 

§ 253 of claims 15 and 16. See J.A. 5075. Ultimately, the

district court denied HP’s motion, finding that claim 6 had 

not been improperly broadened. J.A. 59–62; see also 

J.A. 40–42. In the same order, the district court also construed the claim term “secondary power source” consistent 

with the earlier district court actions to require that the 

“secondary power source be physically separate from the 

driving points of the main power source.” J.A. 52–53; see 

also J.A. 32–33. 

We do not agree that claim 6 is invalid for improper

broadening based on the addition of claims 15 and 16. Our 

broadening inquiry begins and ends with claim 6. Claim 6 

was not itself amended during the ’401 reexamination.

And as HP admits, “[t]he district court’s construction [after 

reexamination] is consistent with how the [earlier district]

courts construed this term [pre-reexamination].” 

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Appellee’s Br. 15. Neither party appeals that construction. 

There can be no dispute, therefore, that the scope of claim 6 

was not changed as a result of the ’401 reexamination. 

Where the scope of claim 6 has not changed, there has not 

been improper claim broadening, and HP’s argument fails. 

See Creo Prods., 305 F.3d at 1344. 

Furthermore, our precedent is clear that “dependent 

claims cannot broaden an independent claim from which 

they depend.” Enzo Biochem Inc. v. Applera Corp., 780 

F.3d 1149, 1156–57 (Fed. Cir. 2017). Thus, even were dependent claims 15 and 16 broader than unamended, independent claim 6, the remedy would not be to find claim 6 

invalid as broadened, but to invalidate added claims 15 and 

16. See MBO Labs., Inc. v. Becton, Dickinson & Co., 602 

F.3d 1306, 1319 (Fed. Cir. 2010). We need not determine 

whether claims 15 and 16 are invalid because they are not 

asserted and because those claims have already been canceled through Network-1’s statutory disclaimer. 

Despite the clarity of our caselaw, HP principally relies

on ArcelorMittal France v. AK Steel Corp., 786 F.3d 885 

(Fed. Cir. 2015), to argue that claim 6 was improperly 

broadened and should be invalidated. In that case, we concluded that the patentee had improperly broadened independent claim 1 through reissue by adding a number of 

dependent claims. See ArcelorMittal, 786 F.3d at 890. HP 

quotes our explanation that one of the new dependent 

claims had “the practical effect of expanding the scope of 

claim 1 to cover claim scope expressly rejected by a previous claim construction ruling.” Appellee’s Br. 70 (quoting 

ArcelorMittal, 786 F.3d at 890). HP also emphasizes that 

in ArcelorMittal, we held invalid for improper broadening 

under 35 U.S.C. § 251 not only the newly added claims but 

also claim 1 itself. Appellee’s Br. 70. HP argues that the 

facts in ArcelorMittal are “nearly identical” to this case, 

and that claim 6 is invalid because claims 15 and 16 have 

“the practical effect of expanding” the scope of claim 6. Id. 

HP is wrong.

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ArcelorMittal is inapposite. In that case, the patentee

had stipulated that all reissued claims, including claim 1,

were broader than the original claims. ArcelorMittal, 786 

F.3d at 890. Thus, in ArcelorMittal, there was no dispute 

that the claims had been broadened. Furthermore, we did 

not hold, as HP suggests, see Appellee’s Br. 70–71, that a 

dependent claim added during reissue (or reexamination)

may broaden and therefore invalidate an unamended, independent claim. To the contrary, we rejected “the argument that a defective reissue application invalidates . . . 

[the] original claims carried over from the original application.” ArcelorMittal, 786 F.3d at 891 (quoting Hewlett–

Packard Co. v. Bausch & Lomb, Inc., 882 F.2d 1556, 1566 

(Fed. Cir. 1989)).

Accordingly, we affirm the district court’s conclusion 

that claim 6 and the other asserted claims are not invalid 

due to improper claim broadening.

CONCLUSION

We have considered the parties’ remaining arguments 

and find them unpersuasive. For the reasons described 

above, we affirm-in-part, reverse-in-part, vacate, and remand.

AFFIRMED-IN-PART, REVERSED-IN-PART, 

VACATED, AND REMANDED

COSTS

The parties shall bear their own costs.

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