United States Court of Appeals for the Federal Circuit 

2008-1578 

(Interference No. 105, 477) 

THOMAS J. YORKEY, 

Appellant, 

v. 

MOHAMED K. DIAB, ESMAIEL KIANI-AZRBAY JANY, 

and WALTER M. WEBER, 

Appellees. 

Robert C. Morgan, Ropes & Gray LLP, of New York, New York, argued for 

appellant. With him on the brief was Marina Len. 

Joseph R. Re, Knobbe, Martens, Olson & Bear, LLP, of Irvine, California, argued 

for appellees. With him on the brief were Brenton R. Babcock, Irfan A. Lateef and 

Jarom D. Kesler. 

Appealed from: United States Patent and Trademark Office 

 Board of Patent Appeals and Interferences 

 
United States Court of Appeals for the Federal Circuit 

2008-1578 

(Interference No. 105, 477) 

THOMAS J. YORKEY, 

 Appellant, 

v. 

 MOHAMED K. DIAB, ESMAIEL KIANI-AZRBAY JANY, 

and WALTER M. WEBER, 

 

Appellees. 

Appeal from the United States Patent and Trademark Office, Board of Patent Appeals 

and Interferences. 

 __________________________ 

DECIDED: April 7, 2010 

 __________________________ 

Before MICHEL, Chief Judge, Gajarsa, Circuit Judge, and Kendall, District Judge1

. 

MICHEL, Chief Judge. 

Appellant Thomas J. Yorkey (“Yorkey”) appeals from a ruling of the Board of 

Patent Appeals and Interferences (the “Board”) denying his motion for judgment that 

claim 39 of Appellees Mohamed K. Diab, Esmaiel Kiani-Azraby Jany and Walter M. 

Weber’s (collectively “Diab”) U.S. Patent Application Ser. No. 09/111,604 (the “Diab 

application”) fails to comply with the written description requirement of 35 U.S.C. § 112, 

¶ 1. Yorkey also appeals the Board’s denial of his motion for judgment of no 

 

1 Hon. Virginia M. Kendall, U.S. District Court for the Northern District of Illinois, sitting by designation. 
interference-in-fact with respect to Yorkey’s U.S. Patent No. 5,645,060 (the “Yorkey 

patent”). We affirm the Board’s rulings. 

PROCEDURAL HISTORY 

The Yorkey patent and Diab application both claim inventions and methods for 

measuring the concentration of oxygen in blood. Yorkey is named as the inventor of the 

Yorkey Patent, which issued on July 8, 1997 and was based on U.S. Application Ser. 

No. 08/490,315, filed on June 14, 1995. The patent was subsequently assigned to 

Nellcor Puritan Bennet, Inc. (“Nellcor”) which is the party in interest. Diab is the named 

inventor on the basis of the Diab application filed on July 6, 1998, which claims priority 

in turn from U.S. Application Ser. Nos. 08/859,837 (filed May 16, 1997) and 08/320,154 

(filed October 7, 1994); the party in interest in the Diab application is Masimo 

Corporation of Irvine, California. 

An interference (No. 105,477) was declared by the Board on July 18, 2006. The 

interference comprised a single count, Count 1, corresponding to claim 6 of the Yorkey 

patent and claim 39 of the Diab application. As in the companion interference to this 

case, Yorkey was designated the junior party and Diab the senior party. See Yorkey v. 

Diab, No. 2008-1577 (hereinafter “Yorkey I”). On June 28, 2007, the Board ruled on two 

motions brought by Yorkey, denying both his motion for judgment that claim 39 of the 

Diab application fails to comply with the written description requirement of 35 U.S.C. § 

112, ¶ 1 (“Motion 1”) and his motion for judgment of no interference-in-fact (“Motion 2”). 

The Board subsequently denied Yorkey’s motion for judgment based on priority of 

invention and, on May 28, 2008, awarded priority to the Diab application and invalidated 

the Yorkey patent. This appeal timely followed. 

2008-1578 2
BACKGROUND 

The technology at issue in this case is medical instrumentation and methods for 

the noninvasive measurement of the concentration of oxygen in the blood of a patient 

(saturation) and has been described in the companion opinion to this case. Count I of 

the interference corresponds to Claim 6 of the Yorkey patent and claim 39 of the Diab 

application. Yorkey Claim 6 recites: 

A method for measuring saturation of a blood constituent in a patient 

comprising the steps of: 

. . . . 

representing each of said intensity signals as a function of said saturation, 

the wavelength corresponding to the intensity signal, and a time-variable 

motion term corresponding to motion noise, said motion terms being 

proportional to one another for each of said intensity signals; and 

solving the three functions to obtain a value for said saturation, 

wherein each of said functions includes a plurality of coefficients, and 

further comprising the step of determining a set of coefficients for said 

third intensity signal from a measurement in the absence of motion noise 

and a determination of said saturation from said first and second intensity 

signals. 

Whereas Diab Claim 39 recites: 

A method for measuring saturation of a blood constituent in a patient 

comprising the steps of: 

. . . . 

representing each of said intensity signals as a function of concentration, 

the wavelength corresponding to the intensity signal, and a time-variable 

motion term corresponding to motion noise, said motion terms being 

proportional to one another for each of said intensity signals; and 

solving the functions to obtain a value for said saturation, 

wherein each of said functions includes a plurality of coefficients related to 

the wavelengths, the coefficients of said third function being determined 

based upon the coefficients of the first and second functions, and further 

comprising the steps of approximating at least a portion of said first and 

second intensity signals based upon the third intensity signal, and 

2008-1578 3
determining said saturation from said approximation of said first and 

second intensity signals. 

(material variations in text emphasized). 

 The principal issue of this appeal stems from the last two limitations of each 

claim. In the penultimate limitation of its claim 6, the Yorkey patent specifies that “three 

functions” (one derived from the signal detected at each wavelength of light emitted by 

the sensor probe) are solved to obtain a saturation value, whereas the corresponding 

limitation of the Diab application states that “the functions” are solved to obtain a 

saturation value. 

The final limitations of the respective claims also differ in the language they 

employ. The Yorkey patent states that its steps constitute a determination of a set of 

coefficients for the third measured intensity signal from a measurement in the absence 

of motion noise, and a determination of oxygen saturation from the first and second 

intensity signals. The corresponding claim limitation from the Diab application recites 

that the coefficient of the third function is determined based upon the coefficients 

determined for the first and second signals, and that subsequent steps approximate at 

least a portion of the first and second intensity signals based upon the third intensity 

signal. The oxygen saturation is subsequently derived from an approximation of the first 

and second intensity signals. 

DISCUSSION 

We have jurisdiction to hear this appeal under 28 U.S.C. § 1295(a)(4)(A) and 35 

U.S.C. § 141. See In re Ferguson, 558 F.3d 1359, 1362 (Fed. Cir. 2009). 

Because Yorkey’s appeal challenges the Board’s claim construction, we first 

address Yorkey’s Motion 2, seeking a judgment of no interference-in-fact. As the junior 

2008-1578 4
party, Yorkey has the burden of showing, by a preponderance of the evidence, that the 

Diab application’s claim 39 and the Yorkey patent’s claim 6 do not interfere-in-fact. See

37 C.F.R. § 41.202(d); In re Garner, 508 F.3d 1376, 1377 (Fed. Cir. 2007). 

 The standard for determining whether an interference exists is set forth in 37 

C.F.R. § 41.203(a): 

An interference exists if the subject matter of a claim of one party would, if 

prior art, have anticipated or rendered obvious the subject matter of a 

claim of the opposing party and vice versa. 

Under this standard, Yorkey must prove either that its claims, if prior art, would neither 

have anticipated, nor have rendered obvious, the subject matter of Diab’s claim or vice 

versa. 

Determination that a claim is anticipated under 35 U.S.C. § 102(b) involves two 

analytical steps: (1) the Board must interpret the claim language; and (2) the Board 

must then compare the construed claim to a prior art reference and make factual 

findings that “each and every limitation is found either expressly or inherently in [that] 

single prior art reference.” In re Crish, 393 F.3d 1253, 1256 (Fed. Cir. 2004) (quoting 

Celeritas Techs. Ltd. v. Rockwell Int'l Corp., 150 F.3d 1354, 1360 (Fed. Cir. 1998) 

(alteration in original). We review those factual findings for substantial evidence. In re 

Gartside, 203 F.3d 1305, 1315 (Fed. Cir. 2000). Because we find that the asserted 

Yorkey patent claim was anticipated by the corresponding claim of the Diab application, 

we need not address the question of obviousness. 

Moreover, because the PTO, in its claim construction, is entitled to give claims 

their broadest reasonable interpretation, our review of the Board's claim construction is 

limited to determining only whether the claim construction was reasonable. See 37 

2008-1578 5
C.F.R. § 41.200(b) (“A claim shall be given its broadest reasonable construction in light 

of the specification of the application or patent in which it appears.”); Crish, 393 F.3d at 

1256 (“[O]ur review of the Board's claim construction is limited to determining whether it 

was reasonable.”). 

Both parties agree that the initial issue in this appeal turns upon the Board’s 

construction of Diab’s claim 39. Yorkey argued to the Board that the claims at issue 

differ because “[c]laim 39 of Diab’s . . . application uses only two functions to obtain 

saturation, and recites ‘approximating at least a portion of said first and second intensity 

signals based upon the third intensity signal’, whereas claim[ ] 6 . . . of Yorkey’s . . . 

patent use[s] all three functions to obtain saturation, and do[es] not approximate a 

portion of the first and second intensity signals based upon the third intensity signal.” 

Yorkey’s expert witness, Dr. Elvir Causevic (“Causevic”), stated that each of the 

three wavelength intensity signals is directly used in the final calculation of saturation by 

the use of matrix algebra. Causevic testified that, in contrast, Diab’s claimed invention 

obtains the saturation value “based on solving two (not three) functions to calculate its 

saturation and using the third wavelength for ‘approximating at least a portion of said 

first and second intensity signals based upon the third intensity signal.’” 

Diab’s expert, Dr. Gail D. Baura (“Baura”), disagreed that the language of 

“solving the three functions” differed from that of “solving the functions.” According to 

Baura: 

Neither the Yorkey claims, nor the Diab [c]laim include a limitation 

requiring that the signals be used without further steps and the functions 

be solved together to calculate the saturation directly. The Yorkey claims 

recite "solving the three functions to obtain a valued [sic, value] for said 

saturation." This limitation does not include a requirement that the signals 

be used without further steps and/or the functions be solved together. 

2008-1578 6
(alterations in original). Baura further disagreed with Causevic that the Diab 

application’s claim does not solve the three functions together, but uses the three 

functions in a few consecutive calculations. According to Baura: 

A person of skill in the art would have knowledge of mathematics and 

linear algebra and understand that here there is no substantive difference 

between solving three functions together and solving them consecutively. 

... It is well known in the art that while matrix algebra can be used to 

simplify mathematical calculations, in substance it performs the same task 

of solving functions consecutively. In fact, a matrix is simply another way 

of writing linear algebraic equations. 

With respect to the final pair of limitations commencing with “wherein”, Causevic 

testified that in Yorkey’s limitation: 

[T]he coefficients of the third wavelength function are determined by taking 

measurements in the absence of motion noise and determining saturation 

from first and second intensity signals....These coefficients are then used 

when intensity measurements are taken in the presence of motion, and all 

three wavelength functions are solved to obtain a value for saturation. 

Causevic averred that Diab’s corresponding limitation claimed “something different” 

because Diab did not claim a “calibration step” but rather “the ultimate determination of 

saturation based on only two wavelengths”, where “the third wavelength is used . . . 

solely to generate a reference signal” 

Baura disagreed, observing that Causevic’s testimony established that Yorkey’s 

claim limitation read on a determination in which the “coefficients of the third wavelength 

have to based at least in part on the coefficients of the first and second intensity 

functions.” Baura further testified that: “[t]he step of approximating a portion of the first 

and second signals is a step in the process of solving the three functions.” Moreover: 

[I]t would have been obvious to a person of skill in the art . . . to eliminate 

the Diab method of approximating a portion of the first and second signals 

2008-1578 7
based on the third signal first and using the approximation to calculate the 

saturation by putting the functions into a matrix and solving the matrix.... 

Thus, a person of ordinary skill in the art having three linear functions 

would have found it obvious to go from solving the functions consecutively 

to pulling all three in a matrix and solving them together. 

The Board found Baura’s testimony to be more credible than that of Causevic 

because it was more consistent with the language of the claims. The Board was not 

persuaded by Yorkey’s argument that solving the three functions to obtain a value for 

oxygen saturation required solving the three functions directly or simultaneously, 

observing that Yorkey did not point to any terms in the claims or any description in the 

specification that compelled such a narrow construction of its own claims. Such a 

narrow construction, held the Board, was not consistent with 37 C.F.R. § 41.200(b)’s 

mandate that a claim be given the broadest reasonable construction. 

Nor did the Board accept Causevic’s argument that Yorkey’s claims exclude the 

Diab application’s approximation step; rather, it accepted Baura’s contention that the 

approximation step is simply a step in the solving of the three functions. The Board held 

that, rather than exclude such approximation steps, Yorkey’s claim, when properly 

construed, embraced them. 

On appeal, Yorkey argues the Board erred in assuming a construction of Diab’s 

claim 39 that equated “solving the functions to obtain a value for saturation” with 

“solving the three functions to obtain a value for saturation.” (emphasis in original). 

This is improper, contends Yorkey, because the language of the limitation states that a 

saturation value is determined from only two of the signals, with the third one merely 

serving as a noise reference to be subtracted. Thus, Diab’s claim 39 cannot be 

construed to require “solving the three functions to obtain a value for saturation.” 

2008-1578 8
According to Yorkey, “such a construction would necessarily require that, regardless of 

which functions are solved for saturation, all three must represent a signal as a function 

of saturation and be solved as such.” 

Yorkey’s argument fails. The specification of the Diab application provides, in 

Equations (93), (94), and (95), the three functions derived from each of the three signals 

recorded from the probe. Each of these functions is time-dependent, as indicated by 

the term Sλn(t) for each function, where n equals one of the three signals, Red1, Red2, 

or IR. Factors in each function are εHbO2,λncA, representing the concentration of 

oxygenated hemoglobin in the blood, and nλn(t), a noise component. Diab teaches that 

each function is solved sequentially to obtain a value for oxygen saturation Thus, 

contra Yorkey, all three functions represent a signal as a function of saturation, and the 

sequential process of the functions’ solution is necessarily required to obtain a final 

value for saturation. 

For these reasons, we find that the Board’s denial of Yorkey’s motion for 

judgment of no interference-in-fact is supported by substantial evidence, and we 

consequently affirm the Board’s decision. 

Yorkey next argues that even if the Board correctly construed the language of 

Claim 39, there is no written description in the Diab application to support it. The written 

description requirement set forth by 35 U.S.C. § 112, ¶ 1 states that: 

The specification shall contain a written description of the invention, and of 

the manner and process of making and using it, in such full, clear, 

concise, and exact terms as to enable any person skilled in the art to 

which it pertains, or with which it is most nearly connected, to make and 

use the same. 

2008-1578 9
35 U.S.C. § 112, ¶ 1. Whether the written description requirement is met is a question 

of fact. Martek Biosciences Corp. v. Nutrinova, Inc., 579 F.3d 1363, 1369 (Fed. Cir. 

2009) (citing Wang Labs., Inc. v. Toshiba Corp., 993 F.2d 858, 865 (Fed. Cir. 1993)). 

The test for sufficiency of support in a parent application is whether the disclosure of the 

application relied upon “reasonably conveys to the artisan that the inventor had 

possession at that time of the later claimed subject matter.” In re Kaslow, 707 F.2d 

1366, 1375 (Fed. Cir.1983). This Court will uphold the Board's finding that the Diab 

application’s claims are adequately described so long as that finding is supported by 

substantial evidence in the record. See Shu-Hui Chen v. Bouchard, 347 F.3d 1299, 

1304 (Fed. Cir. 2003). 

Yorkey contends that the Diab application does not disclose solving three 

intensity signal functions each of which represents a signal as a function of saturation. 

Rather, according to Yorkey, the Diab application discloses solving (at most) only two 

intensity signal functions to determine a value for oxygen saturation; the third signal is 

used merely to generate a noise reference signal that is used to subtract the motioninduced noise component from the other two remaining signals. The resulting functions 

representing those two signals are subsequently solved to yield a value representing 

the oxygen saturation. 

Yorkey disputes Baura’s expert testimony (with which the Board ultimately 

agreed) that the “solving the three functions” limitation is supported because the Diab 

application allegedly discloses “using the third wavelength” to generate a reference 

signal and therefore the third signal is still used in the ultimate calculation of saturation 

Yorkey maintains that the third intensity signal is not represented as a function of 

2008-1578 10
saturation, and testimony concerning “using” signals did not provide support for a claim 

requirement of “solving” three functions, each of which represents a signal as a function 

of saturation. 

The specification of the Diab application first specifies the emitter and detection 

of the third signal at issue: 

The third [light-emitting diode (“LED”)] 304 is used to measure a third 

signal Sλc(t) to be used to determine saturation using the ratiometric 

method. The third LED 304 is time multiplexed with the red and infrared 

LED’s [sic] 300 and 302. Thus, a third signal is input to the common 

processing circuitry in sequence with the signals from red and infrared 

LED’s [sic] 300 and 302. 

.... 

 For pulse oximetry measurements using the ratiometric method, the 

signals (logarithm converted) transmitted ... at each wavelength λa, λb, 

and λc are: 

Sλa(t) = Sλred1(t) = εHbO2, λa cA

HbO2xA

(t) + εHb,λacA

HbxA

(t) + 

εHbO2, λa cV

HbO2xV

(t) + εHb,λacV

HbxV

(t) + nλa(t). (93)

Sλb(t) = Sλred2(t) = εHbO2, λb cA

HbO2xA

(t) + εHb,λbcA

HbxA

(t) + 

εHbO2, λb cV

HbO2xV

(t) + εHb,λbcV

HbxV

(t) + nλb(t). (94)

Sλc(t) = SλIR(t) = εHbO2, λc cA

HbO2xA

(t) + εHb,λccA

HbxA

(t) + 

εHbO2, λc cV

HbO2xV

(t) + εHb,λccV

HbxV

(t) + nλc(t). (95) 2

In each equation, the term Sλ(red1), (red 2), or (IR)(t) refers to the function representing 

the signal detected from each of the three wavelengths emitted by the probe’s LEDs. 

Thus, as a baseline matter, the third signal introduced in this embodiment of the 

invention claimed by the Diab application represented by Equation (94) (the Red2 LED 

signal) is not merely composed of motion-induced noise, but rather contains 

 

2

 Each equation is, of course, a function because the term Sλ(red1) red 2) or (IR)(t) represents 

the result of an operation. 

2008-1578 11
components of both transmitted light representing oxygen saturation (i.e., εHbO2, λb

cA

HbO2xA

(t) + εHb,λbcA

HbxA

(t) + εHbO2, λb cV

HbO2xV

(t) + + εHb, λb cV

HbxV

(t) + nλb(t), where 

HbO2 represents the concentration of oxygen-bound hemoglobin, Hb represents the 

concentration of free hemoglobin, A represents arterial blood, V represents venous 

blood and n represents motion-induced noise). This function is, in effect, identical to the 

other two functions representing the other two signals detected with the exception of the 

varying wavelengths. 

The Diab application teaches that the two red wavelengths are selected to satisfy 

a proportionality relationship which removes the primary signal portions Sλred1(t) and 

Sλred2(t) yielding a secondary reference, n’(t) by choosing two wavelengths that cause 

the primary portions of the measured signals for each to become linearly dependent. 

By so choosing, the venous portions likewise become linearly dependent, which allows 

removal of these signals, generating the secondary reference signal, n’(t). The signal 

so generated can be used in a correlation canceller, such as an adaptive canceller, to 

remove the noise portion of the signal. 

Claim 39 of the Diab application recites, in relevant part: 

[E]ach of said functions includes a plurality of coefficients related to the 

wavelengths, the coefficients of said third function being determined 

based upon the coefficients of the first and second functions, and further 

comprising the steps of approximating at least a portion of said first and 

second intensity signals based upon the third intensity signal, and 

determining said saturation from said approximation of said first and 

second intensity signals. 

In the example of the preferred embodiment recited above from the specification, 

each function (as represented by Equation (93), (94), and (95)) includes a plurality of 

coefficients (both terms relating to Sλred1(t) and Sλred2(t) as well as to nλn(t)), and the 

2008-1578 12
2008-1578 13

coefficients of the third function are based upon the coefficients of the first and second 

functions (and do not merely represent a pure motion-induced noise coefficient). 

Moreover, the recited specification approximates at least a portion of the first and 

second intensity signals based upon the third intensity signal (performed by selecting a 

wavelength for the third emitted signal that satisfies a proportionality relationship which 

removes the primary signal portions Sλred1(t) and Sλred2(t), yielding a secondary 

reference, n’(t), which in turn can be used to refine the relationship between the first and 

secondary signals) which in turn yields a value for the oxygen saturation of the blood, 

based upon the approximation of the first and second signals so derived. 

The language in the limitation thus provides a written description of the limitation 

that would reasonably convey to an artisan of ordinary skill that the inventor had 

possession at that time of the claimed subject matter. See Lockwood v. Am. Airlines, 

Inc., 107 F.3d at 1571-72 (Fed. Cir. 1997). We conclude therefore that there is 

substantial evidence supporting the Board’s denial of Yorkey’s Motion 1 that claim 39 of 

the Diab application fails to comply with the written description of requirement of 35 

U.S.C. § 112, ¶ 1. 

CONCLUSION 

For the reasons set forth above, we affirm the Board’s denial of both Yorkey’s 

motion for a judgment of no interference-in-fact and his motion for judgment that claim 

39 of the Diab application fails to comply with the written description of requirement of 

35 U.S.C. § 112, ¶ 1. 

AFFIRMED