Biosig Instruments, Inc. v. Nautilus, Inc.

United States Court of Appeals

for the Federal Circuit

______________________

BIOSIG INSTRUMENTS, INC.,

Plaintiff-Appellant

v.

NAUTILUS, INC.,

Defendant-Appellee

______________________

2012-1289

______________________

Appeal from the United States District Court for the

Southern District of New York in No. 10-CV-7722, Judge

Alvin K. Hellerstein.

______________________

Decided: April 27, 2015

______________________

MARK DAVID HARRIS, Proskauer Rose LLP, New York,

NY, argued for plaintiff-appellant. Also represented by

PAUL MILCETIC, Villanova, PA; TODD KUPSTAS, Kessler

Topaz Meltzer & Check, LLP, Radnor, PA; DANIEL C.

MULVENY, Barnes & Thornburg LLP, Wilmington, DE;

JOHN E. ROBERTS, Proskauer Rose LLP, Boston, MA.

JOHN D. VANDENBERG, Klarquist Sparkman, LLP,

Portland, OR, argued for defendant-appellee. Also

represented by JAMES E. GERINGER, PHILIP J. WARRICK,

JEFFREY S. LOVE.

BIOSIG INSTRUMENTS, INC. v. NAUTILUS, INC. 2

______________________

Before NEWMAN, SCHALL, and WALLACH, Circuit Judges.

WALLACH, Circuit Judge.

This case is before us on remand from the United

States Supreme Court. Biosig Instruments, Inc. (“Biosig”)

is the assignee of U.S. Patent No. 5,337,753 (“the ’753

patent”), directed to a heart rate monitor associated with

an exercise apparatus and/or exercise procedures. Biosig

brought a patent infringement action against Nautilus,

Inc. (“Nautilus”) in district court alleging that Nautilus

infringed claims 1 and 11 of the ’753 patent. After claim

construction, Nautilus filed a motion for summary

judgment seeking, in relevant portion, to have the ’753

patent held invalid for indefiniteness. The district court

granted Nautilus’s motion, and Biosig appealed. This

court found the claims at issue were not invalid for

indefiniteness, and reversed and remanded for further

proceedings. Nautilus petitioned for certiorari, and the

Supreme Court vacated and remanded this court’s

decision. On remand, we maintain our reversal of the

district court’s determination that Biosig’s patent claims

are indefinite.

BACKGROUND

The facts of this case were recited in detail in this

court’s previous opinion and need not be repeated in full

here. Nautilus, Inc. v. Biosig Instruments, Inc. (Nautilus

I), 715 F.3d 891, 898 (Fed. Cir. 2013) In summary, the

’753 patent is directed to a heart rate monitor that

purports to improve upon the prior art by effectively

eliminating “noise” signals during the process of detecting

a user’s heart rate. ’753 patent col. 1 ll. 5–10. The ’753

patent discloses an apparatus preferably mounted on

exercise equipment that measures heart rates by, inter

alia, processing electrocardiograph (“ECG”) signals from

BIOSIG INSTRUMENTS, INC. v. NAUTILUS, INC. 3

which electromyogram (“EMG”) signals are substantially

removed. Id. col. 1. ll. 36–41. Claim 1 is representative

and recites, in relevant part:

1. A heart rate monitor for use by a user in

association with exercise apparatus and/or

exercise procedures, comprising:

an elongate member;

electronic circuitry including a difference

amplifier having a first input terminal of a first

polarity and a second input terminal of a second

polarity opposite to said first polarity;

said elongate member comprising a first half and

a second half;

a first live electrode and a first common electrode

mounted on said first half in spaced relationship

with each other;

a second live electrode and a second common

electrode mounted on said second half in spaced

relationship with each other;

said first and second common electrodes being

connected to each other and to a point of common

potential . . . .

Id. col. 5 ll. 17–36 (emphases added).

Biosig sued Nautilus for infringement of the ’753

patent in August 2004. After several reexamination

proceedings, Biosig reinstituted a patent infringement

action against Nautilus on October 8, 2010. On August

11, 2011, the district court conducted a Markman hearing,

and on September 29, 2011, issued its order construing

certain disputed claim terms. On November 10, 2011,

Nautilus moved under Federal Rule of Civil Procedure 56

for summary judgment on two issues: infringement and

invalidity for indefiniteness. On February 22, 2012, the

district court granted Nautilus’s motion, holding the ’753

BIOSIG INSTRUMENTS, INC. v. NAUTILUS, INC. 4

patent’s “spaced relationship” term as recited in claim 1

was indefinite as a matter of law. The court did not

decide the issue of infringement.

On appeal, this court reversed and remanded. Citing

precedent, we stated that a claim is indefinite “only when

it is ‘not amenable to construction’ or ‘insolubly

ambiguous.’” Nautilus I, 715 F.3d at 898 (quoting

Datamize, LLC v. Plumtree Software, Inc., 417 F.3d 1342,

1347 (Fed. Cir. 2005)). Under that standard, we

determined the ’753 patent survived indefiniteness

review. Considering the “intrinsic evidence,” we found

that it provided “certain inherent parameters of the

claimed apparatus, which to a skilled artisan may be

sufficient to understand the metes and bounds of ‘spaced

relationship.’” Id. at 899.

The Supreme Court granted certiorari, 134 S. Ct. 896

(2014), and, rejecting our “not amenable to construction or

insolubly ambiguous” standard, vacated and remanded.

Nautilus, Inc. v. Biosig Instruments, Inc. (Nautilus II),

134 S. Ct. 2120 (2014). In its decision, the Court

articulated the standard to be applied: “[W]e hold that a

patent is invalid for indefiniteness if its claims, read in

light of the specification delineating the patent, and the

prosecution history, fail to inform, with reasonable

certainty those skilled in the art about the scope of the

invention.” Id. at 2124 (emphasis added).

This court has jurisdiction pursuant to 28 U.S.C.

§ 1295(a)(1) (2012).

DISCUSSION

I. Standard of Review & Legal Framework

A patent must “conclude with one or more claims

particularly pointing out and distinctly claiming the

subject matter which the applicant regards as [the]

BIOSIG INSTRUMENTS, INC. v. NAUTILUS, INC. 5

invention.” 35 U.S.C. § 112 ¶ 2 (2006). 1 A claim is invalid

for indefiniteness if its language, when read in light of the

specification and the prosecution history, “fail[s] to

inform, with reasonable certainty, those skilled in the art

about the scope of the invention.” Nautilus II, 134 S. Ct.

at 2124. We review the district court’s indefiniteness

determination de novo. Interval Licensing LLC v. AOL,

Inc., 766 F.3d 1364, 1370 (Fed. Cir. 2014).

A patent is presumed valid under 35 U.S.C. § 282 and,

“consistent with that principle, a [fact finder is] instructed

to evaluate . . . whether an invalidity defense has been

proved by clear and convincing evidence.” Microsoft Corp.

v. i4i Ltd. P’ship, 131 S. Ct. 2238, 2241 (2011).

“In the face of an allegation of indefiniteness, general

principles of claim construction apply.” Enzo Biochem,

Inc. v. Applera Corp., 599 F.3d 1325, 1332 (Fed. Cir. 2010)

(internal quotation marks and citation omitted). “In that

regard, claim construction involves consideration of

primarily the intrinsic evidence, viz., the claim language,

the specification, and the prosecution history.” Id.

Though the ultimate construction of a claim term is a

legal question reviewed de novo, underlying factual

determinations made by the district court based on

extrinsic evidence are reviewed for clear error. Teva

Pharm. USA, Inc. v. Sandoz, Inc., 135 S. Ct. 831, 842

(2015). In contrast, “when 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

1 Paragraph 2 of 35 U.S.C. § 112 was replaced with

newly designated § 112(b) when § 4(c) of the Leahy–Smith

America Invents Act (“AIA”), Pub. L. No. 112–29, took

effect on September 16, 2012. Because the application

resulting in the patent was filed before that date, we will

refer to the pre-AIA version of § 112.

BIOSIG INSTRUMENTS, INC. v. NAUTILUS, INC. 6

determination of law, and the Court of Appeals will

review that construction de novo.” Id. at 841.

When a “word of degree” is used, the court must

determine whether the patent provides “some standard

for measuring that degree.” Enzo Biochem, 599 F.3d at

1332; Seattle Box Co., Inc. v. Indus. Crating & Packing,

Inc., 731 F.2d 818, 826 (Fed. Cir. 1984). Recently, this

court explained: “[w]e do not understand the Supreme

Court to have implied in [Nautilus II], and we do not hold

today, that terms of degree are inherently indefinite.

Claim language employing terms of degree has long been

found definite where it provided enough certainty to one

of skill in the art when read in the context of the

invention.” Interval Licensing, 766 F.3d at 1370.

Moreover, when a claim limitation is defined in “purely

functional terms,” a determination of whether the

limitation is sufficiently definite is “highly dependent on

context (e.g., the disclosure in the specification and the

knowledge of a person of ordinary skill in the relevant art

area).” Halliburton Energy Servs., Inc. v. M-I LLC, 514

F.3d 1244, 1255 (Fed. Cir. 2008).

Prior to the Supreme Court’s decision in this case, a

claim was indefinite when it was “insolubly ambiguous” or

“not amenable to construction.” Datamize, 417 F.3d at

1347 (internal quotations and citations omitted). In

Nautilus II, the Supreme Court observed that § 112, ¶ 2

requires “a delicate balance.” 134 S. Ct. at 2128 (quoting

Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., 535

U.S. 722, 731 (2002)). On one hand, the Court noted, the

definiteness requirement must take into account the

inherent limitations of language. “Some modicum of

uncertainty,” the Court recognized, is the “‘price of

ensuring the appropriate incentives for innovation.’” Id.

(quoting Festo Corp, 535 U.S. at 741). On the other hand,

the Court explained, a patent must be precise enough to

afford clear notice of what is claimed, thereby “appris[ing]

the public of what is still open to them. Otherwise there

BIOSIG INSTRUMENTS, INC. v. NAUTILUS, INC. 7

would be a zone of uncertainty which enterprise and

experimentation may enter only at the risk of

infringement claims.” Id. at 2129 (internal quotation

marks and citations omitted). The Court further

explained the policy rationale: “absent a meaningful

definiteness check . . . patent applicants face powerful

incentives to inject ambiguity into their claims.” Id.

Balancing these competing interests, the Supreme

Court held that “[t]o determine the proper office of the

definiteness command, . . . we read § 112, ¶ 2 to require

that a patent’s claims, viewed in light of the specification

and prosecution history, inform those skilled in the art

about the scope of the invention with reasonable

certainty.” Id. (emphasis added). “The standard adopted”

by the Supreme Court “mandates clarity, while

recognizing that absolute precision is unattainable.” Id.

at 2129. It also accords with opinions of the Court stating

that “the certainty which the law requires in patents is

not greater than is reasonable, having regard to their

subject-matter.” Id. (quoting Minerals Separation, Ltd. v.

Hyde, 242 U.S. 261, 270 (1916) (emphasis added)).

II. The Sole Issue Presented Here Is Indefiniteness

On remand from the Supreme Court, the sole issue

presented to this court is whether the district court erred

in holding the ’753 patent invalid for indefiniteness. In

particular, the district court held that “spaced

relationship” as recited in claim 1, and referring to the

spacing between the common and live electrodes, was not

distinctly pointed out and particularly claimed in the

patent in violation of 35 U.S.C. § 112, ¶ 2.

Before this court, Nautilus and Biosig dispute

whether the Supreme Court articulated a new, stricter

standard or whether, in rejecting the phrases “insolubly

ambiguous” and “amenable to construction,” the Court

was primarily clarifying that a patent’s claims must

BIOSIG INSTRUMENTS, INC. v. NAUTILUS, INC. 8

inform those skilled in the art with “reasonable certainty”

of what is claimed.

Nautilus argues the Supreme Court’s mandate

requires this court to find the term “spaced relationship”

indefinite because “the original intrinsic evidence point[s]

in two opposite directions, leaving the claims’

boundaries—and thus the potential avenues for follow-on

innovation—fundamentally uncertain.” Nautilus’s Supp.

Br. 14. According to Nautilus, “spaced relationship” could

mean “a special spacing critical in some way to the recited

result” or it could mean the opposite, that it is not limited

or linked by the recited result. Id. at 14, 17.

Biosig counters that “‘reasonable certainty’ is not a

new standard; it is the degree of clarity in patent claiming

that has governed for nearly one hundred years.” Biosig’s

Supp. Br. 3. According to Biosig, “the Supreme Court did

not indicate that [this court, in Nautilus I,] had been led

astray by either of the disapproved phrases. Its main

concern, rather, was that the use of those phrases by the

Federal Circuit could send the wrong message to district

courts and the patent bar.” Id. at 4 (citing Nautilus II,

134 S. Ct. at 2130 & n.8).

III. Reasonable Certainty Under Nautilus II Is a

Familiar Standard

As the Supreme Court emphasized in Nautilus II,

§ 112 “requires that a patent specification ‘conclude with

one or more claims particularly pointing out and

distinctly claiming the subject matter’” of the invention.

134 S. Ct. at 2124. The Court found too imprecise our

“insolubly ambiguous” standard, and instead held that “a

patent is invalid for indefiniteness if its claims, read in

light of the specification delineating the patent, and the

prosecution history, fail to inform, with reasonable

certainty, those skilled in the art about the scope of the

invention.” Id. (emphasis added).

BIOSIG INSTRUMENTS, INC. v. NAUTILUS, INC. 9

The Court has accordingly modified the standard by

which lower courts examine allegedly ambiguous claims;

we may now steer by the bright star of “reasonable

certainty,” rather than the unreliable compass of

“insoluble ambiguity.”

Reasonableness is the core of much of the common

law, and “reasonable certainty” has been defined in broad

spectra of the law. See, e.g., Palsgraf v. Long Island R.R.

Co., 162 N.E. 99 (N.Y. 1928) (explaining the “reasonable

[person]” foreseeability standard in tort); cf. Jay v. Sec’y of

Dep’t of Health & Human Servs., 998 F.2d 979, 984 (Fed.

Cir. 1993) (discussing whether a reasonable person could

conclude a certain vaccine caused the child’s death). The

Supreme Court has articulated a spectrum for

interpretation of the phrase “reasonable certainty.” 2

2 Prior to Nautilus II, the Court discussed

“reasonable certainty” on numerous occasions. See, e.g.,

Kelo v. City of New London, 545 U.S. 469, 487–88 (2005)

(where petitioners argued the Court should require

“reasonable certainty” that expected public benefits in a

takings case would actually accrue, the Court declined to

impose that “heightened form of review”); Allentown Mack

Sales & Serv., Inc. v. Nat’l Labor Review Bd., 522 U.S.

359, 369 (1998) (express disavowals by more than half of

an employee bargaining unit would establish reasonable

certainty of union nonsupport); Coffy v. Republic Steel

Corp., 447 U.S. 191, 197–99 (1980) (explaining “there

must be a reasonable certainty that the benefit would

have accrued if the employee had not gone into the

military service”); Ala. Power Co. v. Davis, 431 U.S. 581,

587–88, 591 (1977) (reasonable certainty requirement for

accrual of benefits in veteran’s reemployment case

satisfied where work history demonstrates veteran “would

almost certainly have accumulated accredited service”);

Tilton v. Mo. Pac. R.R. Co., 376 U.S. 169, 180–81 (1964);

Boyce Motor Lines v. United States, 342 U.S. 337, 340

BIOSIG INSTRUMENTS, INC. v. NAUTILUS, INC. 10

(1952) (notice of conduct required by criminal statute

must be sufficiently definite to guide its application,

however “[t]he requirement of reasonable certainty does

not preclude the use of ordinary terms to express ideas

which find adequate interpretation in common usage and

understanding”) (emphasis added) (citation omitted);

United States v. Penn. Foundry & Mfg. Co., 337 U.S. 198,

207–08 (1949) (declining to accept the Court of Claims

“rough estimate” as providing the reasonable certainty

required for establishing damages); United Carbon Co. v.

Binney & Smith Co., 317 U.S. 228, 234 (1942) (“What on

first impression [in a patent infringement action] appears

to be reasonable certainty of dimension disappears when

we learn that ‘approximately one-sixteenth of an inch in

diameter’ includes a variation from approximately 1/4th

to 1/100th of an inch. So read, the claims are but

inaccurate suggestions of the functions of the product.”)

(emphasis added); Palmer v. Conn. Ry. & Lighting Co.,

311 U.S. 544, 558, 561 (1941) (“Certainty in the fact of

damage is essential. [Reasonable] [c]ertainty as to the

amount goes no further than to require a basis for a

reasoned conclusion.”); Sheldon v. Metro-Goldwyn

Pictures Corp., 309 U.S. 390, 404 (1940) (analogizing

copyright damages to patent infringement, the Court

found a reasonable certainty requirement satisfied not

with “mathematical exactness,” but only a “reasonable

approximation”); Sproles v. Binford, 286 U.S. 374, 393

(1932) (“The requirement of reasonable certainty does not

preclude the use of ordinary terms to express ideas which

find adequate interpretation in common usage and

understanding,”); Hamilton-Brown Shoe Co. v. Wolf Bros.

& Co., 240 U.S. 251, 261–62 (1916) (analogizing

trademark damages to patent damages and holding “[t]he

difficulty lies in ascertaining what proportion of the profit

is due to the trademark . . . and as this cannot be

ascertained with any reasonable certainty, it is more

consonant with reason and justice that the owner of the

BIOSIG INSTRUMENTS, INC. v. NAUTILUS, INC. 11

Following the issuance of Nautilus II, this court

applied the reasonable certainty standard in DDR

Holdings, LLC v. Hotels.com, 773 F.3d 1245, 1260–61

(Fed. Cir. 2014). (after analogizing to facts from prior

cases and applying a “reasonable certainty” standard,

finding the term “look and feel” had an established

meaning in the art as demonstrated by the trial record,

thus informing those skilled in the art with reasonable

certainty). In Interval Licensing, the “reasonable

certainty” test was applied to determine whether one of

the embodiments provided “a reasonably clear and

exclusive definition,” with a focus on the “relationship”

between the embodiments and the claim language, and

whether the embodiments created “objective boundaries”

for those skilled in the art. 766 F.3d at 1371. The court

also stated:

trademark should have the whole profit than that he

should be deprived of any part of it by the fraudulent act

of the defendant”); Ont. Land Co. v. Yordy, 212 U.S. 152,

157 (1909) (“The first requisite of an adequate description

is that the land shall be identified with reasonable

certainty; but the degree of certainty required is always

qualified by the application of the rule that that is certain

which can be made certain.”) (quoting Jones on Law of

Real Property in Conveyancing § 323); Hetzel v. Balt. &

Ohio R.R. Co., 169 U.S. 26, 38 (1898) (“In many cases

[proof which excludes the possibility of a doubt] cannot be

given, and yet there might be a reasonable certainty,

founded upon inferences legitimately and properly

deducible from the evidence . . . .”); United States v.

Smith, 18 U.S 153, 160–62 (1820) (the crime of piracy is

defined by the law of nations with reasonable certainty);

cf. Bell Atl. Corp. v. Twombly, 550 U.S. 544, 578 n.5

(2007) (Stevens, J., dissenting); Boyde v. California, 494

U.S. 370, 393 n.2 (1990); Thor Power Tool Co. v. Comm’r,

439 U.S. 522, 543–44 (1979); Pub. Util. Comm’n v. United

States, 355 U.S. 534, 552 (1958).

BIOSIG INSTRUMENTS, INC. v. NAUTILUS, INC. 12

We do not understand the Supreme Court to have

implied in Nautilus [II], and we do not hold today,

that terms of degree are inherently indefinite. . . .

Although absolute or mathematical precision is

not required, it is not enough as some of the

language in our prior cases may have suggested to

identify “some standard for measuring the scope

of the phrase.” . . . The patents’ “unobtrusive

manner” phrase is highly subjective, and, on its

face, provides little guidance to one of skill in the

art. . . . The patents contemplate a variety of

stimuli that could impact different users in

different ways. As we have explained, a term of

degree fails to provide sufficient notice of its scope

if it depends on the unpredictable vagaries of any

one person’s opinion.

Id. at 1371–72 (citations omitted); see also Augme Techs.

v. Yahoo!, Inc., 755 F.3d 1326, 1340 (Fed. Cir. 2014) (A

limitation “clear on its face” “unquestionably meets [the

Nautilus II] standard.”).

In the wake of Nautilus II, judges have had no

problem operating under the reasonable certainty

standard. For example, Judge Bryson, sitting by

designation in Texas, stated: “Indefiniteness is a legal

determination; if the court concludes that a person of

ordinary skill in the art, with the aid of the specification,

would understand what is claimed, the claim is not

indefinite.” Freeny v. Apple Inc., No. 2:13-CV-00361-

WCB, 2014 WL 4294505, at *4 (E.D. Tex. Aug. 28, 2014)

(describing the question as whether “a person of ordinary

skill can discern from the claims and specification what

the bounds of the claim are with reasonable certainty”).

After listing numerous fact-specific examples, Judge

Bryson noted that “[c]ontrary to the defendant’s

suggestion, [the Nautilus II] standard does not render all

of the prior Federal Circuit and district court cases

inapplicable” and “all that is required is that the patent

BIOSIG INSTRUMENTS, INC. v. NAUTILUS, INC. 13

apprise [ordinary-skilled artisans] of the scope of the

invention.” Id. at *5. 3

3 Prior to Nautilus II, a number of our cases

applied a reasonable certainty standard in various

contexts. See, e.g., ICU Med., Inc. v. Alaris Med. Sys., 558

F.3d 1368, 1375 (Fed. Cir. 2009) (discussing the

importation of limitations from the specification into the

claims, noting that “the line between construing terms

and importing limitations can be discerned with

reasonable certainty and predictability if the court’s focus

remains on how a person of ordinary skill in the art would

understand the claim terms”) (quoting Phillips v. AWH

Corp., 415 F.3d 1303, 1323 (Fed. Cir. 2005) (en banc)). In

a lost profits damages analysis, we noted the amount

“need not be proved with unerring precision” and held

that lost profits had been proved with reasonable

certainty and that a district court finding to the contrary

was clearly erroneous where the dealer profit margin was

“roughly twenty-five percent of the dealer price.” Ryco,

Inc. v. Ag-Bag Corp., 857 F.2d 1418, 1428 (Fed. Cir. 1988)

(citations omitted). In In re Clarke, 356 F.2d 987, 992

(CCPA 1966), our predecessor court held that “where it

can be concluded that facts . . . in support of a general

allegation of conception and reduction to practice . . .

would persuade one of ordinary skill in the art to a

reasonable certainty that the applicant possessed so much

of the invention as to encompass the reference disclosure,

then that showing should be accepted as establishing a

prima facie case of inventorship.” Finally, our

predecessor noted, in Young v. Bullitt, 233 F.2d 347, 351

(CCPA 1956), that in a priority contest in a patent

interference, “[t]he question generally is whether, when

all the circumstances are considered together, there is a

reasonable certainty as to the identity of the product.

Proof beyond a reasonable doubt is not necessary where

applications were copending.”

BIOSIG INSTRUMENTS, INC. v. NAUTILUS, INC. 14

IV. Biosig’s Claims Inform a Skilled Artisan With

Reasonable Certainty

Considering this background, and the Supreme

Court’s articulated concerns in Nautilus II (the

necessarily inexact balance between “the inherent

limitations of language” and the “modicum of uncertainty”

which is “the price of ensuring the appropriate incentives

for innovation,” on the one hand, and, on the other,

enough precision “to afford clear notice of what is

claimed”), we conclude that Biosig’s claims inform those

skilled in the art with reasonable certainty about the

scope of the invention. Nautilus II, 134 S. Ct. at 2128–29

(internal quotation marks and citations omitted). As we

have stated in the past, “[t]he degree of precision

necessary for adequate claims is a function of the nature

of the subject matter.” Miles Labs., Inc. v. Shandon, Inc.,

997 F.2d 870, 875 (Fed. Cir. 1993) (citing Hybritech Inc. v.

Monoclonal Antibodies, Inc., 802 F.2d 1367, 1375 (Fed.

Cir. 1986)).

On certiorari, the Supreme Court “express[ed] no

opinion on the validity of the patent-in-suit” but rather

instructed this court “to decide the case employing the

standard we have prescribed.” Nautilus II, 134 S. Ct. at

2124.

As an initial matter, since our decision in Nautilus I,

the Supreme Court determined in Teva Pharmaceuticals

USA v. Sandoz that “when 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 the Court of Appeals will

review that construction de novo.” 135 S. Ct. at 841.

However, “when the district court looks beyond the

intrinsic evidence and consults extrinsic evidence, for

example to understand the relevant science, these

subsidiary fact findings are reviewed for clear error.”

BIOSIG INSTRUMENTS, INC. v. NAUTILUS, INC. 15

Enzo Biochem Inc. v. Applera Corp., No. 2014-1321, 2015

WL 1136421, at *4 (Fed. Cir. Mar. 16, 2015).

Our prior analysis primarily relied on intrinsic

evidence and we found the “extrinsic evidence

underscores the intrinsic evidence.” Nautilus I, 715 F.3d

at 901. We revisit the intrinsic evidence here to make

clear that a skilled artisan would understand with

reasonable certainty the scope of the invention.

In relevant part, we noted an ordinarily skilled

artisan would be able to determine this language requires

the spaced relationship to be neither infinitesimally small

nor greater than the width of a user’s hands. Specifically,

we stated:

[T]he district court is correct that the specification

of the ’753 patent does not specifically define

“spaced relationship” with actual parameters, e.g.,

that the space between the live and common

electrodes is one inch. Nevertheless, the ’753

patent’s claim language, specification, and the

figures illustrating the “spaced relationship”

between the live and common electrodes are

telling and provide sufficient clarity to skilled

artisans as to the bounds of this disputed term.

For example, on the one hand, the distance

between the live electrode and the common

electrode cannot be greater than the width of a

user’s hands because claim 1 requires the live and

common electrodes to independently detect

electrical signals at two distinct points of a hand.

On the other hand, it is not feasible that the

distance between the live and common electrodes

be infinitesimally small, effectively merging the

live and common electrodes into a single electrode

with one detection point. See ’753 patent col. 3 ll.

26–31 (describing how each hand is placed over

the live and common electrodes so that they are

BIOSIG INSTRUMENTS, INC. v. NAUTILUS, INC. 16

“in physical and electrical contact with both

electrodes”).

Nautilus I, 715 F.3d at 899.

The prosecution history further illustrates that the

term is not indefinite. In Nautilus I, we considered the

functionality of the claimed heart rate monitor as recited

in claim 1, “which provided the basis for overcoming the

PTO’s office action rejections during the reexamination.”

Id. Specifically, claim 1 provides, in part:

whereby, a first electromyogram signal will be

detected between said first live electrode and said

first common electrode, and a second

electromyogram signal, of substantially equal

magnitude and phase to said first electromyogram

signal will be detected between said second live

electrode and said second common electrode; so

that, when said first electromyogram signal is

applied to said first terminal and said second

electromyogram signal is applied to said second

terminal, the first and second electromyogram

signals will be subtracted from each other to

produce a substantially zero electromyogram

signal at the output of said difference amplifier.

Id. col. 5 ll. 48–61. This “whereby” clause describes the

function of substantially removing EMG signals that

necessarily follows from the previously-recited structure

consisting of the elongate member, the live electrode, and

the common electrode. Id. col. 5 ll. 42–47. As we

described in Nautilus I,

[t]he EMG signal is detected between the live and

common electrodes, which are in a “spaced

relationship” with each other. Even more

significantly, the PTO examiner found this

function to be “crucial” as a reason for overcoming

the cited prior art and confirming the

BIOSIG INSTRUMENTS, INC. v. NAUTILUS, INC. 17

patentability of the asserted claims upon

reexamination. J.A. 139–46. Thus, the recitation

of this function in claim 1 is highly relevant to

ascertaining the proper bounds of the “spaced

relationship” between the live and common

electrodes. See Hoffer v. Microsoft Corp., 405 F.3d

1326, 1329 (Fed. Cir. 2005) (per curiam) (“[W]hen

the ‘whereby’ clause states a condition that is

material to patentability, it cannot be ignored in

order to change the substance of the invention.”).

Nautilus I, 715 F.3d at 900. Not only is the recitation of

this function in claim 1 “highly relevant” to ascertaining

the boundaries of the “spaced relationship” between the

live and common electrodes, it shows

a skilled artisan could apply a test and determine

the “spaced relationship” as pertaining to the

function of substantially removing EMG signals.

Indeed, the test would have included a standard

oscilloscope connected to both the inputs and

outputs of the differential amplifier to view the

signal wave forms and to measure signal

characteristics. With this test, configurations

could have been determined by analyzing the

differential amplifier input and output signals for

detecting EMG and ECG signals and observing

the substantial removal of EMG signals from ECG

signals while simulating an exercise.

Id. at 900–1.

As discussed in detail in Nautilus I, during

prosecution, Biosig also presented evidence in the form of

a declaration by the inventor, Mr. Gregory Lekhtman.

See 01 Communique Lab., Inc. v. LogMeIn, Inc., 687 F.3d

1292, 1298 (Fed. Cir. 2012) (considering statements made

during reexamination as intrinsic evidence for purposes of

claim construction). Mr. Lekhtman argued that when

“configuring the claimed heart rate monitor, skilled

BIOSIG INSTRUMENTS, INC. v. NAUTILUS, INC. 18

artisans can determine the ‘spaced relationship’ between

live and common electrodes by calculating the point in

which EMG signals are substantially removed.” Nautilus

I, 715 F.3d at 900. As we explained, Mr. Lekhtman

testified:

[T]he strength of an EMG signal measurement is

proportional to the space between the active and

ground electrode and the size of the electrodes.

J.A. 194–95. . . . [I]t was common knowledge for

skilled artisans in 1992 that EMG potentials on

each hand would be different, and that the ’753

patent requires a configuration of the detectors

that produce equal EMG signals from the left and

right hands. J.A. 200. This equalization or

balancing . . . is achieved by detecting EMG

signals on the left and right palms, which are

delivered to a differential amplifier in the EMG

measuring device. Available design variables are

then adjusted until the differential output is

minimized, i.e., close to zero, and the ECG to

EMG ratio is determined to be sufficient for an

accurate heart rate determination. J.A. 200–01.

Id.

In this case, a skilled artisan would understand the

inherent parameters of the invention as provided in the

intrinsic evidence. The term “spaced relationship” does

not run afoul of “the innovation-discouraging ‘zone of

uncertainty’ against which [the Supreme Court] has

warned,” and to the contrary, informs a skilled artisan

with reasonable certainty of the scope of the claim.

Interval Licensing, 766 F.3d at 1374 (quoting Nautilus II,

134 S. Ct. at 2130).

CONCLUSION

We conclude the “spaced relationship” phrase

“inform[s] those skilled in the art about the scope of the

BIOSIG INSTRUMENTS, INC. v. NAUTILUS, INC. 19

invention with reasonable certainty.” The claims that

include that phrase comply with Section 112 ¶2.

REVERSED AND REMANDED

COSTS

Each party shall bear its own costs.