NOTE: This disposition is nonprecedential.

United States Court of Appeals 

for the Federal Circuit ______________________ 

EXERGEN CORPORATION,

Plaintiff-Cross-Appellant

v.

KAZ USA, INC.,

Defendant-Appellant

______________________ 

2016-2315, 2016-2341

______________________ 

Appeals from the United States District Court for the 

District of Massachusetts in No. 1:13-cv-10628-RGS, 

Judge Richard G. Stearns.

______________________ 

Decided: March 8, 2018

______________________ 

 KERRY L. TIMBERS, Sunstein Kann Murphy & Timbers 

LLP, Boston, MA, argued for plaintiff-cross-appellant. 

Also represented by ROBERT M. ASHER, JOEL R. LEEMAN,

BRANDON TAYLOR SCRUGGS, SHARONA STERNBERG. 

 PRATIK A. SHAH, Akin, Gump, Strauss, Hauer & Feld, 

LLP, Washington, DC, argued for defendant-appellant. 

Also represented by ZE-WEN JULIUS CHEN, JAMES EDWARD 

TYSSE; DANIEL LYNN MOFFETT, KIRT S. O'NEILL, San 

Antonio, TX.

______________________ 
2 EXERGEN CORP. v. KAZ USA, INC. 

Before MOORE, BRYSON, and HUGHES, Circuit Judges.

Opinion for the court filed by Circuit Judge MOORE. 

Dissenting opinion filed by Circuit Judge HUGHES. 

MOORE, Circuit Judge. 

Kaz USA, Inc. (“Kaz”) appeals the United States District Court for the District of Massachusetts decision 

holding claims 7, 14, and 17 of U.S. Patent No. 6,292,685 

(“’685 patent”) and claims 17, 24, 33, 39, 40, 46, 49, 60, 

and 66 of U.S. Patent No. 7,787,938 (“’938 patent”) directed to patent eligible subject matter. Kaz also appeals 

the district court’s denial of judgment as matter of law on 

noninfringement of the ’685 patent and denial of a new 

trial on damages. Exergen Corp. (“Exergen”) crossappeals the district court’s summary judgment of no 

willful infringement. For the reasons discussed below, we 

affirm-in-part, reverse-in-part, vacate-in-part, and remand for further proceedings. 

BACKGROUND

The ’685 and ’938 patents disclose a body temperature 

detector that calculates a person’s core temperature by 

detecting the temperature of the forehead directly above 

the superficial temporal artery. ’685 patent1 at 2:10–14. 

A person’s core temperature can be computed by applying 

a constant coefficient to the skin and ambient temperature readings. Id. at 3:8–16. The patents explain that the 

superficial temporal artery is ideal for taking temperature 

due to its accessibility, stable blood flow, and temperature 

close to that of the heart. Id. at 3:63–4:8. They teach to 

 

1 The specifications of the ’685 and ’938 patents are 

effectively identical. Unless otherwise specified, citations 

to the ’685 patent refer to both patents.
EXERGEN CORP. v. KAZ USA, INC. 3

“locate the temporal artery, a temperature sensor, preferably a radiation detector 20, is scanned across the side of 

the forehead over the temporal artery while electronics in 

the detector search for the peak reading which indicates 

the temporal artery.” Id. at 4:9–13. The patents further 

explain that prior art temperature detectors did not 

“provide the unique combination of elements which enable 

consistent measurements of core temperature by scanning 

across a superficial artery.” Id. at 8:54–60. For example, 

prior art detectors were not adapted to scan across a 

target surface by taking multiple samples per second or 

were based on a pivoting scan rather than a lateral scan. 

Id. at 8:60–9:8.

The claims at issue include both apparatus claims and

method claims. Claim 49 which depends from claim 48 of 

the ’685 patent, an apparatus claim, recites: 

48. A body temperature detector comprising:

a radiation detector; and

electronics that measure radiation from at 

least three readings per second of the radiation detector as a target skin surface 

over an artery is viewed, the artery having 

a relatively constant blood flow, and that 

process the measured radiation to provide 

a body temperature approximation, distinct from skin surface temperature, based 

on detected radiation.

49. The body temperature detector of claim 

48 wherein the artery is a temporal artery.
4 EXERGEN CORP. v. KAZ USA, INC. 

Claim 24, which depends from claim 14, of the ’938 patent, a method claim, recites2: 

14. A method of detecting human body temperature comprising making at least three radiation 

readings per second while moving a radiation detector to scan across a region of skin over an artery to electronically determine a body 

temperature approximation, distinct from skin 

surface temperature.

24. The method of claim 14 wherein the artery is 

a temporal artery. 

Exergen sued Kaz and two other competitors, Brooklands Inc. and Thermomedics Inc., in the District of 

Massachusetts, and the three suits proceeded separately 

with different judges. The parties and judges involved 

agreed to consolidate claim construction for the three 

cases, but all other matters were resolved separately. In 

the Brooklands suit, the district court held claims 51 and 

54 of the ’938 patent ineligible under 35 U.S.C. § 101. 

Exergen Corp. v. Brooklands Inc., 125 F. Supp. 3d 307, 

312–17 (D. Mass. 2015). In the Thermomedics suit, the 

district court held claims 51, 52, 54, and 55 of the ’938 

patent ineligible under § 101. Exergen Corp. v. Thermomedics, Inc., 132 F. Supp. 3d 200, 203–08 (D. Mass. 2015), 

aff’d sub nom. Exergen Corp. v. Sanomedics Int’l Holdings, Inc., 653 F. App’x 760 (Fed. Cir. 2016). 

 

2 Appellant argues that method claim 14 is representative of the claims at issue on appeal. Appellant’s 

Corrected Principal Br. 6. Appellee argues the twelve 

claims at issue separately grouping them by their common limitations. See, e.g., Cross Appellant’s Principal & 

Resp. Br. 12–13, 37–47. 
EXERGEN CORP. v. KAZ USA, INC. 5

Kaz moved for summary judgment, asserting that the 

Thermomedics judgment had preclusive effect. The 

district court denied Kaz’s motion with respect to the 

claims currently on appeal. The district court also granted Kaz’s pre-trial motion for summary judgment of no 

willful infringement. 

After trial, the jury found all asserted claims infringed and not invalid and awarded Exergen $9,802,228 

in lost profits and $4,840,320 in reasonable royalties. No 

factual or legal issues regarding patent eligibility under 

§ 101 were submitted to the jury. 

After post-trial briefing, the district court, with the 

benefit of the evidence presented at trial and “[g]uided by 

the jury’s verdict, and by the pleadings specific to this 

case,” denied judgment of invalidity under § 101. 

J.A. 105. It also summarily denied Kaz’s motions for 

judgment as a matter of law with respect to noninfringement and for a new trial on damages. Kaz appeals the 

district court’s denial of its motions with respect to § 101, 

noninfringement, and damages. Exergen cross-appeals 

the district court’s grant of summary judgment of no 

willful infringement. We have jurisdiction under 28 

U.S.C. § 1295(a)(1).

DISCUSSION

In patent appeals, we apply the law of the regional 

circuit, here the First Circuit, to issues not unique to 

patent law. AbbVie Deutschland GmbH & Co., KG v. 

Janssen Biotech, Inc., 759 F.3d 1285, 1295 (Fed. Cir. 

2014). The First Circuit reviews the grant or denial of 

motions for summary judgment de novo. Id. It reviews 

the denial of judgment as a matter of law de novo, only 

reversing if the facts and inferences point so strongly and 

overwhelmingly in favor of the movant that a reasonable 

jury could not have reached a verdict against that party. 

Id. at 1297. The First Circuit also reviews the denial of a 

motion for a new trial for abuse of discretion. Id. at 1302. 
6 EXERGEN CORP. v. KAZ USA, INC. 

I. Patent Eligibility

Patent eligibility under 35 U.S.C. § 101 is an issue of 

law we review de novo. Intellectual Ventures I LLC v. 

Capital One Fin. Corp., 850 F.3d 1332, 1338 (Fed. Cir. 

2017). Anyone who “invents or discovers any new and 

useful process, machine, manufacture, or composition of 

matter, or any new and useful improvement thereof” may 

obtain a patent. 35 U.S.C. § 101. Because patent protection does not extend to claims that monopolize the “building blocks of human ingenuity,” claims directed to laws of 

nature, natural phenomena, and abstract ideas are not 

patent eligible. Alice Corp. Pty. v. CLS Bank Int’l, 134 S. 

Ct. 2347, 2354 (2014). The Supreme Court instructs 

courts to distinguish between claims that claim patent 

ineligible subject matter and those that “integrate the 

building blocks into something more.” Id. First, we 

“determine whether the claims at issue are directed to a 

patent-ineligible concept.” Id. at 2355. If so, we “examine 

the elements of the claim to determine whether it contains an ‘inventive concept’ sufficient to ‘transform’ the 

claimed abstract idea into a patent-eligible application.” 

Id. at 2357 (quoting Mayo Collaborative Servs. v. Prometheus Labs., Inc., 566 U.S. 66, 72, 79 (2012)). If the elements involve “well-understood, routine, [and] 

conventional activity previously engaged in by researchers in the field,” Mayo, 566 U.S. at 73, they do not constitute an “inventive concept.” As argued by the parties, the 

step two dispute in this case turns entirely on whether 

the combination of elements was well-understood, routine, 

and conventional at the time of the invention. In these 

circumstances, the second step of the Mayo/Alice test is 

satisfied when the claim limitations “involve more than 

performance of ‘well-understood, routine, [and] conventional activities previously known to the industry.’” 

Content Extraction & Transmission LLC v. Wells Fargo 

Bank, Nat. Ass’n, 776 F.3d 1343, 1347–48 (Fed. Cir. 2014)

(quoting Alice, 134 S. Ct. at 2359); see also Intellectual 
EXERGEN CORP. v. KAZ USA, INC. 7

Ventures I LLC v. Erie Indem. Co., 850 F.3d 1315, 1328 

(Fed. Cir. 2017) (holding that the features constituting 

the inventive concept in step two of Mayo/Alice “must be 

more than ‘well-understood, routine, conventional activity’” (quoting Mayo, 132 S. Ct. at 1298)); Affinity Labs of 

Texas, LLC v. DIRECTV, LLC, 838 F.3d 1253, 1262 (Fed. 

Cir. 2016) (same); Bascom Glob. Internet Servs., Inc. v. 

AT&T Mobility LLC, 827 F.3d 1341, 1350 (Fed. Cir. 2016)

(“[I]t is of course now standard for a § 101 inquiry to 

consider whether various claim elements simply recite 

‘well-understood, routine, conventional activit[ies].’” 

(second alteration in original) (quoting Alice, 134 S. Ct. at 

2359)).

After trial, the district court denied Kaz’s motion for 

judgment of invalidity under § 101. There is no dispute in 

this case that the asserted claims employ a natural law to 

achieve their purpose. The claims recite a “method of 

detecting human body temperature” and “a body temperature detector” which generally utilize temperature readings from the forehead skin and the ambient temperature 

to calculate an approximate core body temperature. See, 

e.g., ’685 patent at claim 17; ’938 patent at claim 60. And 

a significant portion of the specification is dedicated to 

deriving the mathematical equations to calculate core 

temperature based on ambient and skin temperature 

readings. ’685 patent at 6:58–8:45. What the parties 

dispute, however, is whether the additional claimed steps 

beyond calculating the temperature present a novel 

technique in this computation or add an inventive concept 

sufficient to transform the claims into a patent-eligible 

application. 

The district court reasoned that “while the asserted 

claims are based in natural phenomena,” the claims recite

additional steps which, like the claims in Diamond v. 

Diehr, 450 U.S. 175 (1981), “transformed the underlying 

natural laws into inventive methods and useful devices 

that noninvasively and accurately detect human body 
8 EXERGEN CORP. v. KAZ USA, INC. 

temperature.” J.A. 110, 113–14. The court noted that the 

asserted claims each recite a subset of three steps: (1) 

moving while laterally scanning (’685 patent claims 7, 14, 

and 17; ’938 patent claims 17, 24, 33, 60, and 66); (2) 

obtaining a peak temperature reading (’685 patent claim 

7; ’938 patent claims 60 and 66); and (3) obtaining at least 

three readings per second (’938 patent claims 17, 24, 39, 

40, 46, and 49). Kaz argued both below and on appeal 

that these additional elements were known in the prior 

art. The district court held simply being known in the art 

did not suffice to establish that the subject matter was not 

eligible for patenting. The district court recognized that a 

“new combination of steps in a process may be patentable 

even though all the constituents of the combination were 

well known and in common use before the combination 

was made.” J.A. 112 (quoting Diehr, 450 U.S. at 188). The 

district court found that though these claim elements may 

have been known in the art, they were “previously utilized to detect hot spots indicating injury or tumors, or 

surface temperature differentials,” not used to solve the 

problem of detecting arterial temperature beneath the 

skin. J.A. 112–13. For example, the jury heard testimony 

that a known technique for scanning tissue and using 

differential ambient and scanned temperatures was used 

to detect injury in horses, not take human body temperature. Likewise, the prior art DermaTemp product used a 

sensor that could take readings ten times a second and

“lock on the highest temperature,” but this product was 

used to scan differential surface temperatures for diagnostic purposes “to find an injury or a hot spot.”3 

 

3 The dissent suggests Exergen’s claimed invention 

amounts to simply using DermaTemp, a preexisting 

temperature detector to take a measurement of forehead 

skin temperature. Dissent at 5. The patentee presented 

evidence that the DermaTemp product was not, however, 
EXERGEN CORP. v. KAZ USA, INC. 9

J.A. 5319, 15565. And these methods made no use of the 

newly calculated coefficient for translating measurements 

taken at the forehead into core body temperature readings. After considering all the trial testimony and evidence, the district court found that “there is no evidence 

in the record” that these methods were well-understood, 

routine, and conventional prior to the introduction of 

Exergen’ s invention. J.A. 113. 

The district court’s conclusion that these claim elements were not well-understood, routine, and conventional is a question of fact to which we must give clear error 

deference. Like indefiniteness, enablement, or obviousness, whether a claim is directed to patentable subject 

matter is a question of law based on underlying facts. 

Akzo Nobel Coatings, Inc. v. Dow Chem. Co., 811 F.3d 

1334, 1343 (Fed. Cir. 2016) (“Indefiniteness is a question 

of law that we review de novo, subject to a determination 

of underlying facts.” (citation omitted)); Alcon Research 

Ltd. v. Barr Labs., Inc., 745 F.3d 1180, 1188 (Fed. Cir. 

2014) (“Whether a claim satisfies the enablement requirement of 35 U.S.C. § 112 is a question of law that we 

review without deference, although the determination 

may be based on underlying factual findings, which we 

review for clear error.”); Apple Inc. v. Samsung Elecs. Co., 

839 F.3d 1034, 1047 (Fed. Cir. 2016) (en banc) (“Obviousness is a question of law based on underlying facts.”). We 

have previously stated that while the § 101 inquiry is 

 

capable of measuring core body temperature by scanning 

across the forehead due to its design. J.A. 15561–62, 

15568, 15586, 15683. We cannot say, based on the evidence of record, that the district court clearly erred when 

it concluded that the DermaTemp product did not result 

in the claimed combination being well-understood, routine, and conventional. 
10 EXERGEN CORP. v. KAZ USA, INC. 

ultimately a legal question, sometimes the inquiry may 

contain underlying factual issues. Mortg. Grader, Inc. v. 

First Choice Loan Servs. Inc., 811 F.3d 1314, 1325 (Fed. 

Cir. 2016); Accenture Glob. Servs., GmbH v. Guidewire 

Software, Inc., 728 F.3d 1336, 1342 (Fed. Cir. 2013). And 

the Supreme Court recognized that in making the § 101 

determination, the inquiry “might sometimes overlap” 

with other fact-intensive inquiries like novelty under 

§ 102. Mayo, 566 U.S. at 90. 

As our cases demonstrate, not every § 101 determination contains disputes over the underlying facts. See, e.g., 

Content Extraction, 776 F.3d at 1349 (patent owner 

conceded the argued inventive concept “was a routine 

function of scanning technology at the time the claims 

were filed”); Intellectual Ventures I LLC v. Capital One 

Bank (USA), 792 F.3d 1363, 1370 (Fed. Cir. 2015) (patent 

owner argued an “interactive interface” is “a specific 

application of the abstract idea that provides an inventive 

concept” and did not dispute that the computer interface 

was generic). As we indicated in Berkheimer v. HP Inc., 

No. 2017-1437, at 13 (Fed. Cir. Feb. 8, 2018), “[n]othing in 

this decision should be viewed as casting doubt on the 

propriety of those cases.” 

The question of whether a claim element is wellunderstood, routine, and conventional to a skilled artisan 

in the relevant field is a question of fact and deference 

must be given to the determination made by the fact 

finder on this issue. Something is not well-understood, 

routine, and conventional merely because it is disclosed in 

a prior art reference. There are many obscure references 

that nonetheless qualify as prior art. For example, we 

have held that a single copy of a thesis written in German 

and located in a German university library was a printed 

publication because that thesis was available to the 

public. In re Hall, 781 F.2d 897, 897–900 (Fed. Cir. 1986). 

This type of evidence, for example, would not suffice to 

establish that something is “well-understood, routine, and 
EXERGEN CORP. v. KAZ USA, INC. 11

conventional activity previously engaged in by scientists 

who work in the field.” Mayo, 566 U.S. at 79.4 

This case is not like either Mayo or Ariosa, where 

well-known, existing methods were utilized to determine 

the existence of a natural phenomenon. In Mayo, the 

claimed method was directed to measuring metabolite 

levels in the blood (and determining the relationship to 

toxicity and effectiveness), a “natural law.” 566 U.S. at 

77. The methods of measurement “were well known in 

the art” and were “well-understood, routine, conventional 

activity.” Id. at 80. Similarly, in Ariosa the claimed 

method was directed to measuring fetal DNA in the 

mother’s blood, a “naturally occurring phenomenon.” 

Ariosa Diagnostics, Inc. v. Sequenom, Inc., 788 F.3d 1371, 

1376 (Fed. Cir. 2015), cert denied, 136 S. Ct. 2511 (2016). 

The measurement method there, too, was “conventional, 

routine and well understood.” Id. at 1378.

This case is different. Here, the patent is directed to 

the measurement of a natural phenomenon (core body 

temperature). Even if the concept of such measurement is 

directed to a natural phenomenon and is abstract at step 

one, the measurement method here was not conventional, 

routine, and well-understood. Following years and millions of dollars of testing and development, the inventor 

determined for the first time the coefficient representing 

 

4 In this case, the district court held that whether 

the technique of scanning while moving a radiation detector was well-understood, routine, and conventional was a 

“close” question. J.A. 94. It noted that Kaz had shown 

that 30-year-old patents disclosed such scanning. However, the court found that Kaz had the burden of proof and 

that based on the evidence before it, “it is unclear whether 

this technique has become so prevalent as to be routine or 

conventional.” J.A. 94.
12 EXERGEN CORP. v. KAZ USA, INC. 

the relationship between temporal-arterial temperature 

and core body temperature and incorporated that discovery into an unconventional method of temperature measurement. As a result, the method is patent eligible, 

similar to the method of curing rubber held eligible in

Diehr.5 In other words, at the second step of Mayo/Alice, 

the patent incorporated an inventive concept. The same 

is true here. The inventor “transformed the process into 

an inventive application of the formula.” Id. at 81.

In Alice, the claims recited only the method for exchanging financial obligations and a generic computer 

system. 134 S. Ct. at 2353. There was no dispute in that 

case that the use of a generic computer in implementing 

the method was well-understood and conventional; the 

only argument advanced by the patent-holder at step two 

was that “the claims are patent eligible because these 

steps require a substantial and meaningful role for the 

computer.” Id. at 2359 (internal quotation omitted). In 

Mayo, the Supreme Court noted that the patents themselves stated that the claimed methods for determining 

metabolite levels were well-known in the art, an issue 

which was not disputed by the parties. 566 U.S. at 79. 

The Supreme Court did not hold that district court fact 

finding was not entitled to deference. 

In Ariosa, like Mayo, there was no dispute that the 

claimed methods were well-known, routine and conventional. We cited the patent specification and prosecution 

history which repeatedly conceded this point. 788 F.3d at 

1377 (“The ’540 patent provides that ‘[t]he preparation of 

 

5 In Mayo, the Supreme Court cited Diehr for the 

proposition that “a process is not unpatentable simply 

because it contains a law of nature or a mathematical 

algorithm.” 566 U.S. at 71 (quoting Diehr, 450 U.S. at 

187).
EXERGEN CORP. v. KAZ USA, INC. 13

serum or plasma from the material blood sample is carried out by standard techniques.’” (quoting specification)); 

id. (“[The specification] provides that ‘[s]tandard nucleic 

acid amplification systems can be used . . . .’” (quoting 

specification)); id. at 1378 (“[O]ne skilled in the art is 

aware of a variety of techniques which might be used to 

detect different nucleic acid species. . . . These techniques 

are a matter of routine for one skilled in the art for the 

analysis of DNA.” (quoting prosecution history)); id.

(“[O]ne skilled in the art is readily able to apply the 

teachings of the present invention to any one of the wellknown techniques for detection of DNA . . . .” (quoting 

prosecution history)). And the parties did not dispute this 

issue. In such a case, with no contrary evidence, no 

genuine issue of fact existed to prevent summary judgment. 

In Bascom, we reversed the 12(b)(6) dismissal holding 

“[o]n this limited record, this specific method of filtering 

Internet content cannot be said, as a matter of law, to 

have been conventional or generic.” Bascom Glob. Internet Servs., 827 F.3d at 1350. Rather than suggest that 

this inquiry is a legal one, this suggests it is very much a 

factual one. In Bascom, we did not reverse without deference the district court’s determination regarding wellunderstood, conventional and routine, we held that there 

were sufficient allegations to support an inventive concept 

and that “[w]e find nothing on this record that refutes 

those allegations as matter of law or justifies dismissal 

under 12(b)(6).” Id. at 1352.

The dissent does not dispute that whether claim elements are well-understood, routine, and conventional in a 

particular art at a particular time is a fact finding. Nor 

does it dispute that such fact findings by the district court 

after a full trial on the merits are entitled to deference 

and should be reviewed for clear error. Instead, the 

dissent argues that the district court’s fact finding in this 

case regarding whether the claimed temperature meas-
14 EXERGEN CORP. v. KAZ USA, INC. 

urement method is well-understood, routine, and conventional is clearly erroneous. For the reasons discussed, we 

do not agree. 

After a trial, the district court in this case concluded 

that the claimed combination at issue was not proven to 

be well-understood, routine, and conventional. It cited 

the evidence presented at trial and from the patent specifications. This is a fact finding reviewed for clear error. 

We conclude that the district court fact finding that the 

claimed combination was not proven to be wellunderstood, routine, and conventional is not clearly 

erroneous. 

Kaz also argues that it was inappropriate for the district court to make these fact findings because it had a 

Seventh Amendment right to have a jury resolve any 

underlying factual disputes. The Seventh Amendment 

preserves the right to a jury trial for “[s]uits at common 

law.” U.S. Const. Amend. VII. The Supreme Court has 

construed this language to require a jury trial for those 

actions in which only legal rights and remedies are at 

issue, as opposed to equitable rights and remedies. Tull 

v. United States, 481 U.S. 412, 417 (1987). Whether a 

modern statutory cause of action satisfies this language 

requires a two-step inquiry, first comparing the “action to 

18th-century actions brought in the courts of England 

prior to the merger of the courts of law and equity,” and 

second, examining the remedy sought to determine 

whether it is legal or equitable in nature. Id. at 417–18. 

Kaz analogizes patent eligibility to obviousness, arguing 

that both are legal questions with underlying factual 

components to which a right to trial by jury exists. Kaz 

acknowledges that there are legal questions in patent 

cases which can contain underlying factual components 

such as claim construction to which there is no right to 

trial by jury. 
EXERGEN CORP. v. KAZ USA, INC. 15

Whether the Seventh Amendment guarantees a jury 

trial on any factual underpinnings of § 101 is a question 

which awaits more in-depth development and briefing 

than the limited discussion in this case. We need not 

decide that question in this case because Kaz waived its 

right to a jury trial for the factual issues underlying the 

§ 101 determination in this case. 

Three actions by Kaz demonstrate waiver of any 

potential right to a jury trial for fact issues underlying 

§ 101. First, in the joint pretrial memorandum, Kaz 

agreed that § 101 is “a question of law to be decided by 

the Court” and “[t]o the extent the Court elects to have the

jury decide underlying factual issues relevant to § 101, 

the parties submit proposed special interrogatories in 

their respective proposed special verdict questions.” 

J.A. 13979–80 (emphasis added). The use of the word 

“elects” indicates that the parties agreed that the district 

court may, in its discretion, opt to send fact issues to the 

jury or not. Second, during trial, when the district court 

informed the parties that it would not give the jury any 

special verdict questions on § 101 because the jury may 

confuse the obviousness inquiry with the well-understood, 

conventional, routine inquiry, Kaz did not object. See

Marcano-Rivera v. Pueblo Int’l, Inc., 232 F.3d 245, 253 n.4 

(1st Cir. 2000) (“In this Circuit, ‘[s]ilence after instructions, including instructions on the form of the verdict to 

be returned by the jury, typically constitutes a waiver of 

any objections.’” (alteration in original) (quoting Putnam 

Res. v. Pateman, 958 F.2d 448, 456 (1st Cir. 1992))); see 

also Fed. R. Civ. P. 49(a)(3). Finally, in the introduction 

of its post-trial motion for judgment of invalidity, Kaz 

stated, “§ 101 is an issue for the Court to resolve now, in 

the first instance, as both the finder of fact and the arbiter 

of law.” J.A. 16672 (emphasis added). These three affirmative actions, occurring before, during, and after trial, 

demonstrate that Kaz acquiesced in the district court’s 

resolution of any underlying fact questions. 
16 EXERGEN CORP. v. KAZ USA, INC. 

II. Infringement of the ’685 Patent

Claims 7, 14, and 17 of the ’685 patent recite “computing an internal body temperature” as a “function of 

ambient temperature and” either “the peak temperature 

reading” (claim 7) or “sensed surface temperature” (claims 

14 and 17). All three claims require detecting temperature by laterally scanning a detector across the forehead. 

The parties’ joint claim construction statement stipulated 

that “internal body temperature” means “temperature of a 

region of the body existing beneath the sensed surface.” 

The parties agree that the “sensed surface” in the claims

is the forehead. Therefore, the limitations requiring 

“computing an internal body temperature,” according to 

the parties’ agreed construction, requires computing the 

temperature of a region of the body existing beneath the 

forehead. 

The district court correctly instructed the jury on the 

claim construction, and the jury found claims 7, 14, and 

17 of the ’685 patent infringed. The district court denied 

Kaz’s post-trial motion for judgment of noninfringement 

as a matter of law, reasoning that evidence supported a 

finding that the “temperature of a region of the body 

existing beneath the sensed surface” limitation was met 

because the oral-equivalent temperature “reported by the 

accused devices was not the measured oral temperature, 

and was higher than the skin temperature, but lower 

than the temperature of the temporal artery.” J.A. 57. 

We review the jury’s infringement findings for substantial 

evidence. Hewlett-Packard Co. v. Mustek Sys., Inc., 340 

F.3d 1314, 1318 (Fed. Cir. 2003). 

Kaz argues the jury’s verdict of direct infringement of 

’685 claims 7, 14, and 17 is not supported by substantial 

evidence because the accused devices calculate an oralequivalent temperature, not the temperature of the body 

beneath the forehead. We agree and reverse the verdict of 
EXERGEN CORP. v. KAZ USA, INC. 17

infringement with respect to claims 7, 14, and 17 of the 

’685 patent.

It is undisputed how the accused devices work: they 

measure the temperature at the forehead and the ambient temperature, and then they use look-up tables stored 

in memory to determine the oral-equivalent temperature

that is provided to the user. The claims as construed, 

however, require computing the temperature of a region 

of the body existing beneath the forehead, not the oralequivalent temperature.

The record evidence demonstrates that because warm

blood circulates throughout the body’s arteries, and 

because other body temperatures range from the surface 

temperature of the skin to the arterial temperature, both 

the oral-equivalent temperature and the temperature of 

the body beneath the forehead may operate within the 

same range of temperatures. But demonstrating that two 

different temperatures operate within the same range is 

not the same as demonstrating that the accused devices 

actually compute the temperature of a particular region of 

the body. Though the oral-equivalent temperature may 

be insubstantially different from the temperature of the 

area of the body beneath the forehead, infringement 

under the doctrine of equivalents is not an issue in this 

case. 

Exergen argues its expert testified that the accused 

devices add temperature back in to the measured forehead surface temperature to compensate for the heat loss, 

so the accused devices therefore calculate the temperature 

of the region of tissue beneath the forehead skin. At best, 

Exergen’s cited testimony demonstrates that the oralequivalent temperature calculated by the accused devices 

approximates the temperature of the body beneath the 

forehead. While this evidence supports the jury’s infringement verdict for the asserted claims of the ’938 

patent, each of which requires a determination of a “body 
18 EXERGEN CORP. v. KAZ USA, INC. 

temperature approximation,” it does not evidence that the 

devices compute the temperature of the region of the body 

existing beneath the forehead. Unlike the ’685 claims, the 

’938 claims’ recitation of the term “approximation” indicates that the claims do not expressly require computation of the temperature under the scanned area, so long as 

the calculation approximates the temperature under the 

scanned area. Therefore, while this testimony supports 

the jury’s infringement verdict with respect to the ’938 

claims, it cannot support the jury’s verdict with respect to 

the asserted ’685 claims. We conclude that the jury’s 

determination of infringement of ’685 claims 7, 14, and 17 

is not supported by substantial evidence. 

III. Damages

35 U.S.C. § 284 allows damages “adequate to compensate for the infringement, but in no event less than a 

reasonable royalty for the use made of the invention by 

the infringer, together with interest and costs as fixed by 

the court.” The patent owner, upon proving infringement, 

may receive a reasonable royalty or lost profits, but not 

both for the same infringing units. Asetek Danmark A/S

v. CMI USA Inc., 852 F.3d 1352, 1362 (Fed. Cir. 2017). 

The jury’s determination of the amount of damages is a 

fact question that we review for substantial evidence, and 

we review the underlying methodology, including consistency of the award with governing legal principles, for 

abuse of discretion. Id.

Kaz argues both the reasonable royalty and lost profits portions of the jury’s damages award are unsupported 

by substantial evidence. It argues that the reasonable 

royalty part of the jury’s award translates into a per-unit 

rate of 32% of the projected sales price and 71% of Kaz’s 

projected per-unit net profit. It argues the hypothetical, 

nonexclusive, U.S.-only royalty agreement contemplated 

in this case should be set at a rate less than 5.7%, the rate 

for the worldwide and exclusive license agreement Kaz 
EXERGEN CORP. v. KAZ USA, INC. 19

entered for a different thermometer. Kaz also argues the 

lost profits portion of the jury award improperly included 

lost profits for CVS stores, where Exergen did not sell any 

products. 

While a royalty that would have given Exergen 71% of 

Kaz’s projected net profit is certainly steep, we do not 

review such fact findings de novo. There was substantial 

evidence presented at trial which supports the jury’s 

conclusion that in a hypothetical negotiation, Kaz would 

have been willing to pay such a price to enter the market. 

Exergen’s damages expert went through each of the 

factors in Georgia-Pacific Corp. v. U.S. Plywood Corp., 

318 F. Supp. 1116 (S.D.N.Y. 1970), explaining why each 

relevant factor weighed in favor of a high royalty rate. 

For instance, Exergen’s expert explained that the parties 

were “fierce competitors” at the time of the hypothetical 

negotiation, and Exergen would have known that if it

licensed the patents to Kaz, it would have lost sales. 

J.A. 16287. He testified that Exergen had no licenses 

with respect to the patents-in-suit, and would have needed to be “highly incentivized” to license the patents for a 

technology with “advantages that other products didn’t 

have, namely, the noninvasive, the gentle nature of the 

product.” J.A. 16294, 16297. He further testified that 

Kaz would have been incentivized to “pay a slightly 

higher royalty” because there were nine years left on the 

patents, which would have been a long time to sit out of a 

growing market. J.A. 16296. The jury was not required 

to give more weight to Kaz’s license, particularly in light 

of mitigating testimony that the agreement was for a 

different type of thermometer “of unknown appeal,” was 

based on patent applications, and was not between competitors. J.A. 16419–20. Kaz has not presented any 

evidence that the jury’s reasonable royalty would not have 

been feasible from a business perspective—indeed, Kaz 

would have still made 29% of its projected per-unit profit. 

The jury was entitled to credit Exergen’s evidence that 
20 EXERGEN CORP. v. KAZ USA, INC. 

Kaz would have been highly motivated to pay a premium 

to enter the market.

The jury’s lost profits award with respect to CVS, the 

only retailer disputed on appeal, is also supported by 

substantial evidence. Trial testimony established that 

CVS offers its own generic products alongside a single 

branded product. The jury was entitled to find that had 

Kaz’s thermometers not been on the market, CVS would 

have chosen Exergen’s competing product to be the 

branded product. While “the patentee needs to have been 

selling some item, the profits of which have been lost due 

to infringing sales, in order to claim damages consisting of 

lost profits,” Poly-America, L.P. v. GSE Lining Tech., Inc., 

383 F.3d 1303, 1311 (Fed. Cir. 2004), our precedent does 

not require sales to have been lost in any particular way. 

Even though the inventor testified that CVS did not carry 

Exergen’s products because Exergen previously sued them 

for patent infringement, the jury was entitled to find that 

in the absence of a feasible alternative product, CVS 

would have turned to Exergen despite their history of 

litigation. Trial testimony demonstrated that another 

major retailer who Exergen had previously sued “got over 

it” and later carried Exergen’s product. J.A. 16411–13. 

We hold that both portions of the jury’s damage award 

are supported by substantial evidence. However, because 

we reverse the jury’s finding of infringement for claims 7,

14, and 17 of the ’685 patent, we vacate the damage 

award and remand to the district court to determine the

consequences of our holding for the award. The parties 

agree that a recalculation of damages would be necessary, 

but dispute whether a new trial on damages is warranted. 

We leave this to the district court.

IV. Enhanced Damages

We review the district court’s decision on enhanced 

damages under 35 U.S.C. § 284 for abuse of discretion. 

Halo Elecs., Inc. v. Pulse Elecs., Inc., 136 S. Ct. 1923, 1934
EXERGEN CORP. v. KAZ USA, INC. 21

(2016). In Halo, the Supreme Court rejected our previous 

test for willful infringement as one that “unduly confines 

the ability of district courts to exercise the discretion 

conferred on them.” Id. at 1935 (rejecting In re Seagate 

Tech., LLC, 497 F.3d 1360, 1371 (Fed. Cir. 2007)). 

In this case, the district court granted summary 

judgment of no willfulness prior to the Halo decision and 

held that because Kaz’s invalidity contentions were not 

objectively unreasonable, it need not decide the subjective 

prong of Seagate. After additional briefing following the 

Supreme Court’s grant of certiorari in Halo, the district 

court denied Exergen’s post-trial motion for enhanced 

damages. It reviewed the factors in Read Corp. v. Portec, 

Inc., 970 F.2d 816, 827 (Fed. Cir. 1992), and held “[e]ven 

absent the [Seagate] willfulness threshold, the Read

factors do not compel enhanced damages in this case.” 

J.A. 54. 

We cannot conclude that the district court abused its

discretion in applying the Read factors and declining to 

award enhanced damages. Because the Supreme Court 

held that Seagate’s requirement of “a finding of objective 

recklessness in every case before district courts may 

award enhanced damages” unduly restricted the discretion of the district court, Halo, 136 S. Ct. at 1932, we have 

vacated previous enhanced damages decisions premised 

only on Seagate’s objective prong. See, e.g., Alfred E. 

Mann Found. for Sci. Research v. Cochlear Corp., 841 

F.3d 1334, 1345 (Fed. Cir. 2016); WesternGeco L.L.C. v. 

ION Geophysical Corp., 837 F.3d 1358, 1363 (Fed. Cir. 

2016). But in this case the district court’s summary 

judgment of no willfulness based on the objective prong of 

Seagate was not the only rationale on the record. The 

district court did not clearly err in its later consideration 

of the Read factors. For example, the district court found

that no evidence of copying existed, that no concealment 

or litigation misconduct had occurred, and that Exergen 

was able to “more than adequately vindicate its rights.” 
22 EXERGEN CORP. v. KAZ USA, INC. 

J.A. 54. Consistent with the exercise of its discretion, 

Halo, 136 S. Ct. at 1933, the district court took into 

account the particular circumstances of this case and 

concluded “on balance, this case is not of an exceptional 

nature warranting an award of multiple damages.” 

J.A. 54.

Exergen argues a jury must consider willfulness before the district court may exercise its discretion to enhance damages under § 284, but such a blanket rule is 

directly contrary to the Supreme Court’s mandate that 

courts exercise their discretion free from inelastic rules 

like the Seagate test. Halo, 136 S. Ct. at 1933–34; see

Arctic Cat Inc. v. Bombardier Recreational Prod. Inc., 876 

F.3d 1350, 1371–72 (Fed. Cir. 2017) (refusing to adopt a 

blanket rule that a district court abuses its discretion by 

deciding an issue without briefing by the parties). Even if 

the jury had found that Kaz’s infringement was willful, 

“an award of enhanced damages does not necessarily flow 

from a willfulness finding.” Presidio Components, Inc. v. 

Am. Tech. Ceramics Corp., 875 F.3d 1369, 1382 (Fed. Cir. 

2017). Under the circumstances of this case, the district 

court did not abuse its discretion in analyzing the Read

factors, taking into account the overall circumstances of 

the case, and denying enhanced damages. We affirm the 

district court’s denial of enhanced damages.

CONCLUSION

For the foregoing reasons, we affirm the district 

court’s denial of judgment as a matter of law that the 

claims were ineligible under 35 U.S.C. § 101 and its 

denial of enhanced damages in this case. We reverse the 

verdict of infringement with respect to claims 7, 14, and 

17 of the ’685 patent. We see no clear error in the award 

of damages for both reasonable royalty and lost profits. 

We nonetheless vacate and remand the damage award for 

a determination by the district court of the impact our 
EXERGEN CORP. v. KAZ USA, INC. 23

reversal of infringement of the ’685 patent claims has on 

the damage award. 

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

VACATED-IN-PART, AND REMANDED

COSTS

No costs.
United States Court of Appeals 

for the Federal Circuit ______________________ 

EXERGEN CORPORATION,

Plaintiff-Cross-Appellant

v.

KAZ USA, INC.,

Defendant-Appellant

______________________ 

2016-2315, 2016-2341

______________________ 

Appeals from the United States District Court for the 

District of Massachusetts in No. 1:13-cv-10628-RGS, 

Judge Richard G. Stearns.

______________________ 

HUGHES, Circuit Judge, dissenting. 

We determine whether a patent claims eligible subject 

matter under 35 U.S.C. § 101 through a two-step test. 

Mayo Collaborative Servs. v. Prometheus Labs., Inc., 566 

U.S. 66 (2012). At step one, we determine whether the 

claims are directed toward a patent-ineligible concept. 

Alice Corp. Pty. v. CLS Bank Int’l, 134 S. Ct. 2347, 2355

(2014). If so, we consider at step two whether the claims 

nonetheless embody a sufficiently inventive concept to 

transform the claimed invention into a patent-eligible 

application. Id. (quoting Mayo, 566 U.S. at 78). 

The majority reaches step two, affirming the district 

court’s determination that the claims of the ’685 and ’938 

patents embody inventive concepts. In my view, the 
2 EXERGEN CORP. v. KAZ USA, INC. 

claimed inventions merely calculate a law of nature using 

conventional, commercially available technology. Following the principle that well-understood, routine, and 

conventional activities cannot supply an inventive concept, I would find the asserted claims are patent ineligible 

under § 101. Thus, I respectfully dissent from the majority’s conclusion that the asserted claims are patent eligible. 

I 

The majority’s opinion does not appear to decide 

whether the asserted claims are directed toward an 

ineligible concept at step one. The majority recognizes 

“[t]here is no dispute . . . that the asserted claims employ 

a natural law to achieve their purpose,” Maj. Op. at 7, but 

not every invention that makes use of a natural law is 

directed toward a law of nature, see Rapid Litig. Mgmt. 

Ltd. v. CellzDirect, Inc., 827 F.3d 1042, 1048–49 (Fed. Cir. 

2016). While the district court noted that it was “persuaded” of the claims’ patent eligibility at step one, J.A. 

110, the majority focuses exclusively on the parts of the 

district court’s decision that concern whether the claim 

elements were well-understood, routine, or conventional, 

see Maj. Op. at 8–11. 

In my view, the asserted claims are directed toward 

the law of nature that governs the relationship between 

core body temperature and forehead skin temperature. 

An invention is directed to a patent-ineligible concept 

when it “begins and ends” with that concept. Ariosa 

Diagnostics, Inc. v. Sequenom, Inc., 788 F.3d 1371, 1376 

(Fed. Cir. 2015). In Ariosa, the claimed methods began 

with a cffDNA sample taken from maternal plasma and 

ended with isolated, paternally inherited cffDNA. Id. 

Because both cffDNA’s presence in maternal plasma and 

the existence of paternally inherited cffDNA were natural 

phenomenon, the claimed methods were directed toward 

patent-ineligible natural phenomenon. Id. Relatedly, 
EXERGEN CORP. v. KAZ USA, INC. 3

claims are directed to patent-ineligible concepts “when 

they amount[] to nothing more than observing or identifying the ineligible concept itself.” See Rapid Litig., 827 

F.3d at 1048. 

The asserted claims begin and end with a law of nature. The claims cover temperature detectors that calculate a person’s core body temperature. ’685 patent col. 2 

l. 60–col. 3 l. 12. The claimed invention first detects

ambient air temperature and the temperature of forehead 

skin directly over the temporal artery. Id. at col. 2 ll. 10–

14. It then inputs these temperatures into a “heat balance equation,” a mathematical representation of the law 

of nature that governs the relationship between skin, air, 

and core temperatures. Id. at col. 7 l. 3–col. 8 l. 8. This 

heat balance equation applies the principle that heat 

generated by a person’s body flows throughout the body

and, eventually, into the environment. The prior art 

recognized long ago that this principle enabled the calculation of core body temperature from skin and air temperature measurements. For instance, in 1989 Exergen filed 

an application that became U.S. Patent No. 5,012,813, 

which discloses a radiation detecting thermometer that 

uses the heat balance relationship between ear skin

temperature and core temperature. Because heat does 

not flow from the body’s core to every area of skin in the 

same way, the heat balance approach to measuring core 

temperature requires identifying a coefficient that corresponds to the relationship between core temperature and 

the temperature of the specific area of skin being measured. The novel feature of the heat balance equation used 

by the ’685 and ’938 inventions is the inventor’s identification through empirical testing of the coefficient that

governs the relationship between core temperature and 

the temperature of skin above the temporal artery. The 

claimed invention uses this heat balance equation to 

calculate and display the person’s core body temperature. 

Id. at col. 3 ll. 17–19. Unlike in Diamond v. Diehr, where 
4 EXERGEN CORP. v. KAZ USA, INC. 

a patentable invention used Arrhenius’ equation as an 

intermediate step in a rubber curing process, 450 U.S. 

175, 191–93 (1981), Exergen’s claimed invention amounts 

to nothing more than an observation of the natural phenomenon governed by the heat balance equation. The 

invention begins by detecting the equation’s inputs and 

ends by displaying its output. Thus, the asserted claims 

are directed toward a patent-ineligible law of nature. 

At step two, if claims are directed to a patentineligible concept, we “consider the elements of each claim 

both individually and ‘as an ordered combination’ to 

determine whether the additional elements ‘transform the 

nature of the claim’ into a patent-eligible application.” 

Alice, 134 S. Ct. at 2355 (quoting Mayo, 566 U.S. at 78–

79). These transformative elements must supply an 

“inventive concept” that ensures the patent amounts to 

“significantly more than a patent upon the [ineligible 

concept] itself.” Id. (quoting Mayo, 566 U.S. at 72–73) 

(alteration in original). Claim elements that recite “conventional, routine and well understood applications in the 

art” are insufficient to “supply an inventive concept.” 

Ariosa, 788 F.3d at 1378. 

Even under a deferential standard of review, the district court clearly erred by finding that the claims of the

’685 and ’938 patents embody an inventive concept. The 

asserted claims recite a temperature detector that performs a subset of three steps: (1) moving while laterally 

scanning over an artery or forehead; (2) obtaining a peak 

temperature reading; and (3) taking plural skin temperature measurements per second. See, e.g., ’685 patent 

col. 9 ll. 41–43; ’938 patent col. 10 ll. 60–67. Most of the 

claims also recite using a radiation detector. Temperature-detecting products that make use of these elements 

have existed for decades. The district court recognized 

that “patents dating from more than 30 years ago disclosed the technique of scanning while moving a radiation 

detecting device.” J.A. 94. For example, U.S. Patent No. 
EXERGEN CORP. v. KAZ USA, INC. 5

3,351,642, issued in 1970, describes an infrared thermometer with a sensor that permits “scanning across a portion 

of a patient’s body, for example a forehead.” J.A. 17594. 

Similarly, obtaining peak temperatures and taking multiple measurements per second are ubiquitous features in 

the prior art. The ’685 and ’938 specifications disclose 

that these features are present in Exergen’s other products, including its D501 Industrial Temperature Detector 

and prior ear temperature detectors. ’685 patent col. 8 l. 

60–col. 9 l. 4; ’938 patent col. 9 ll. 2–15. 

At the time of invention, the combination of these elements into a single product was also well-known. For 

instance, the district court recognized that Exergen 

commercially sold DermaTemp, a radiation detecting 

thermometer capable of taking ten readings per second 

and tracking peak temperatures. The district court found

that these devices were scanned over skin to “detect hot 

spots indicating injury or tumors, or surface temperature 

differentials.” J.A. 112. This finding aligns with the 

DermaTemp operating manual, which indicates that 

DermaTemp could be used to measure forehead temperature in order to detect surgery side effects. The district 

court therefore recognized that prior art products combined skin scanning, obtaining peak temperatures, and 

taking multiple temperature measurements per second. 

These findings reveal that, aside from its use of a newly 

discovered heat balance coefficient, Exergen’s claimed 

invention amounts to nothing more than using a preexisting temperature detector to take a conventional and 

routine measurement of forehead skin temperature. 

Absent the patent-ineligible law of nature, the claimed 

invention consists entirely of elements already combined

by the prior art. Thus, the claimed combination of 

elements lacks an inventive concept because the combination was well-understood, routine and conventional at the 

time of invention. 
6 EXERGEN CORP. v. KAZ USA, INC. 

In reaching the opposite conclusion, the district court 

legally erred by using a law of nature to supply an inventive concept. The district court never found that the 

combination of taking multiple measurements while 

scanning laterally across the forehead to determine peak 

temperature was not well-understood, routine, and conventional. It only found that there was “no evidence . . . 

that these steps were ‘well-understood, routine, [or] 

conventional[ly]’ used to detect arterial temperature beneath the skin.” J.A. 113 (alterations in original) (emphasis added). Rather than finding that the claim elements 

were not routine or conventional, the district court focused on whether those elements were routinely or conventionally used for the purpose of calculating core body 

temperature. It differentiated the claimed invention from 

the prior art solely on the basis that the claimed invention 

“solve[s] a different problem.” J.A. 112.

We rejected identical reasoning in Ariosa. There, the 

patentee argued its claimed methods of amplifying and 

detecting paternal cffDNA in maternal plasma supplied 

an inventive concept because such methods had never 

been used on maternal plasma samples. Ariosa, 788 F.3d 

at 1379. We noted that the claimed cffDNA amplification 

and detection methods were well-understood, routine and 

conventional. Id. at 1378. As a result, the patentee’s 

argument implied that the inventive concept lied solely in 

the natural phenomenon that paternal cffDNA exists in 

maternal plasma. Id. at 1379. Although the claimed 

methods solved a novel problem, using conventional

techniques for a new purpose did not supply an inventive 

concept that amounted to significantly more than the 

natural phenomenon to which the claims were directed. 

Here, the district court similarly erred. Despite recognizing that temperature detectors identical to the 

claimed invention already existed for other purposes, the 

district court reasoned that these prior detectors never 

used forehead skin temperature measurements to calcu-
EXERGEN CORP. v. KAZ USA, INC. 7

late core body temperature. Like in Ariosa, this reasoning

implicitly relies upon the relationship between forehead 

skin temperature and core body temperature to supply an 

inventive concept. Although the invention calculates core 

body temperature from forehead temperature, those 

calculations merely reflect the natural relationship between forehead and core body temperatures. Accordingly, 

the district court clearly erred by finding an inventive 

concept based on the asserted claims’ use of wellunderstood, routine, and conventional temperaturemeasuring techniques for this new purpose. 

The majority attempts to salvage the district court’s 

decision by emphasizing the novelty of the heat balance 

coefficient. In doing so, the majority misapplies the step 

two analysis from the Mayo/Alice framework. Step two is 

“a search for an ‘inventive concept’—i.e., an element or 

combination of elements that is ‘sufficient to ensure that 

the patent in practice amounts to significantly more than 

a patent upon the [ineligible concept] itself.’” Alice, 134 S. 

Ct. at 2355 (internal quotation marks omitted) (quoting 

Mayo, 566 U.S. at 72–73). After identifying an ineligible 

concept at step one, we ask at step two “[w]hat else is 

there in the claims before us?” Mayo, 566 U.S. at 78. 

Clearly, a patent-ineligible law of nature cannot be the 

inventive concept that ensures the claimed invention 

amounts to significantly more than a patent upon that 

law of nature. Yet the majority argues exactly that, 

reasoning that Exergen’s temperature detector is “unconventional” at step two because it uses “for the first time 

the coefficient representing the relationship between 

temporal-arterial temperature and core body temperature.” Maj. Op. at 11–12. The majority’s analysis fails to 

identify any combination of claim elements that is not 

well-understood, routine, and conventional aside from the 

use of a newly discovered law of nature. This is unsurprising because the prior art contains temperature detectors like DermaTemp that incorporate every element of 
8 EXERGEN CORP. v. KAZ USA, INC. 

the claimed invention besides the heat balance equation. 

To overcome the claimed invention’s lack of an inventive 

concept, the majority opinion erroneously conflates step 

two with a novelty inquiry. Cf. Mayo, 566 U.S. at 90 (“[I]n 

evaluating the significance of additional steps, the § 101 

patent-eligibility inquiry and, say, the § 102 novelty 

inquiry might sometimes overlap. But . . . to shift the 

patent-eligibility inquiry entirely to these later sections 

risks creating significantly greater legal uncertainty, 

while assuming that those sections can do work that they 

are not equipped to do.”). 

I am not suggesting that considering the integration 

of a law of nature into the claimed invention is improper 

at every stage of § 101 analysis. Indeed, step one requires 

us to examine the claims holistically in order to determine 

whether they are directed to an ineligible concept. See

Enfish, LLC v. Microsoft Corp., 822 F.3d 1327, 1335 (Fed. 

Cir. 2016) (“Rather, the ‘directed to’ inquiry applies a 

stage-one filter to claims, considered in light of the specification, based on whether ‘their character as a whole is 

directed to excluded subject matter.’” (quoting Internet 

Patents Corp. v. Active Network, Inc., 790 F.3d 1343, 1346 

(Fed.Cir.2015))). Upon reaching step two, however, we 

focus more narrowly on the claim elements other than the 

invention’s use of the ineligible concept to which it is 

directed. Accordingly, the majority’s analysis of the 

claims as a whole belongs at step one. At either step, 

however, for the reasons discussed above, a claimed 

invention’s unconventionality, by itself, is not sufficient to 

render the claim patent eligible. 

II

Based on the foregoing, I would find that the asserted 

claims of the ’685 and ’938 patents are directed to the law 

of nature that governs the relationship between core body 

temperature and forehead skin temperature, and that the 

claims lack an inventive concept sufficient to transform
EXERGEN CORP. v. KAZ USA, INC. 9

them into patent-eligible inventions. Because this renders the asserted claims patent-ineligible subject matter

under § 101, I would not reach the remaining issues on 

appeal. Accordingly, I respectfully dissent.