Yorkey v. Diab

United States Court of Appeals for the Federal Circuit

2008-1577

(Interference No. 105, 471)

THOMAS J. YORKEY,

Appellant,

v.

MOHAMED K. DIAB, ESMAIEL KIANI-AZRBAY JANY,

IBRAHIM M. ELFADEL, REX J. MCCARTHY,

WALTER M. WEBER, and ROBERT A. SMITH,

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

2008-1577

(Interference No. 105, 471)

THOMAS J. YORKEY,

Appellant,

v.

MOHAMED K. DIAB, ESMAIEL KIANI-AZRBAY JANY,

IBRAHIM M. ELFADEL, REX J. MCCARTHY,

WALTER M. WEBER and ROBERT A. SMITH,

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 Judge 1 .

MICHEL, Chief Judge.

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

Patent Appeals and Interferences (the “Board”) denying his motion seeking invalidity of

claims 16-18 and 21 of Appellees Mohamed K. Diab, Esmaiel Kiani-Azraby Jany,

Ibrahim M. Elfadel, Rex J. McCarthy, Walter M. Weber, and Robert A. Smith’s

(collectively “Diab”) U.S. Patent Application Ser. No. 09/110,542 (the “Diab application”)

1

Hon. Virginia M. Kendall, U.S. District Court for the Northern District of Illinois, sitting

by designation.

on the grounds that the claims fail to comply with the written description requirement of

35 U.S.C. § 112, ¶ 1. Yorkey also appeals from the Board’s ruling that he failed to

establish a prima facie case of actual reduction to practice and the Board’s consequent

award of priority to the Diab application over Yorkey’s U.S. Patent No. 5,645,060 (the

“Yorkey patent”). Because we find that that the asserted claims of the Diab application

meet the written description requirement of § 112, we affirm the Board’s denial of

Yorkey’s motion. However, we reverse the Board’s finding that Yorkey failed to

establish a prima facie case of actual reduction to practice and remand the case to the

Board for further proceedings.

PROCEDURAL HISTORY

The patent and patent application at issue in this appeal claim inventions 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 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

(“Masimo”). An interference (No. 105,471) was declared by the Board on July 18, 2006,

and Yorkey was declared the junior party.

Two counts were declared in the interference: Count 1 included claims 1, 2, 8,

and 12-16 of the Yorkey patent and 15, 19, and 20 of the Diab application; Count 2

2008-1577 2

embraced claims 3-5, 7, 10, 11, and 17 of the Yorkey patent and claims 16-18 and 21 of

the Diab application.

During the motions phase of the interference, Yorkey filed four motions, all of

which were denied by the Board. At issue in the instant appeal is the Board’s denial of

Yorkey’s motion seeking to have Diab’s claims corresponding to Counts 1 and 2 denied

for failure to comply with the written description requirement of 35 U.S.C. § 112, ¶ 1.

Yorkey also appeals the Board’s holding that he failed to establish a prima facie

case that he had reduced his invention to practice prior to Diab’s benefit date of October

7, 1994.

BACKGROUND

The technology at issue in this case is medical instrumentation designed for the

measurement of physiological signals. Specifically, the inventions claimed by the

Yorkey patent and the Diab application are directed at the noninvasive measurement of

the amount of oxygen in the blood of a patient (“pulse oximetry”) which is an indicator of

the healthful function of the pulmonary and cardiovascular systems responsible for the

delivery of oxygen to the body’s tissues.

A major problem in the detection of blood oxygen saturation is the presence of

ambient interference (“noise”) which can obscure the measurement of blood oxygen

saturation by introducing extraneous signals into the recorded measurement. Improving

the signal-to-noise ratio is a central concern in the design of biomedical instrumentation

for detecting physiological signals, which are often weak when compared to background

noise. Certain types of noise can be removed by the use of passive or active bandpass

or notch filters (which filter out signals of frequencies that are outside the range of the

2008-1577 3

signals that the device is attempting to detect). However, if the signal and the noise are

coincident within the same range of frequencies, simple frequency filtering is insufficient

and a means of separating the signal from the noise in which it is embedded must be

contrived.

Prior technologies for the suppression of noise have relied upon the direct

subtraction of noise from the signal. However, the claims at issue in the interference

are directed to a method of noise filtering that does not directly subtract motion-induced

noise from the detected signal. This method relies upon two assumptions: (1) that the

amount of actual motion is the same for each of the two separate intensity signals

measured by the probe (typically one signal is measured from transmitted light in the

red wavelengths of the visible light spectrum and one in the infrared wavelengths); and

(2) the motion component portions of the detected signals are proportionate. The

relevant portion of Count I is set forth below:

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

comprising the steps of:

irradiating said patient with electromagnetic radiation of two discrete,

different wavelengths;

sensing an intensity of said radiation for each of said wavelengths after it

passes through a portion of said patient to produce first and second

intensity signals including motion components; and

determining said saturation by mathematically manipulating said first and

second intensity signals without subtracting said motion components and

with the assumptions that

i) an amount of motion is the same at the same time for each of said

intensity signals, and

ii) the motion components of said intensity signals are proportional to one

another.

2008-1577 4

Count 2 is similar to Count I, but includes additional steps directed to determining

oxygen saturation in the presence of motion-induced interference. Claim 16 of the Diab

application is representative of the claims embraced by Count 2; the claim recites

identical language to Count 1 recited above, and continues after the ellipsis:

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

comprising the steps of:

…

taking the logarithm of each representation of said first and second

intensity signals;

removing signal portions outside a known band of interest to create first

and second filtered signals;

equating the first filtered signal of the first intensity signal to s + n, where n

is the portion of the signal due to motion and s is the portion of the signal

not due to motion;

equating the second filtered signal of the second intensity signal to ras +

rvn, where ra, is a ratio indicative of saturation;

expressing said representations as a matrix;

using said matrix to determine ra, by assuming s and n are uncorrelated;

and determining said saturation from ra. 2

The latter two limitations are at the heart of the first issue in this case.

DISCUSSION

I. Written Description

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

2

ra and rv represent, respectively, ratios corresponding to arterial and venous oxygen

saturation. According to the Diab application, ra is the ratio indicating oxygen saturation,

whereas the motion artifact is in large part due to circulatory movement of venous

blood, therefore rv is a ratio relating the motion component of the two intensity signals.

The term s equals the actual signal (light attenuation as a function of arterial oxygen

saturation) to be measured, and n equals the motion-induced noise.

2008-1577 5

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.

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

parent application “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 argues that the Board erred in finding that the Diab application’s written

description of the Count’s limitations “assuming s and n are uncorrelated” and

“expressing said representations as a matrix” are sufficient to convey to a person of skill

in the art that the patentee had possession of the claimed invention at the time of the

application. Specifically, Yorkey argues that two of the methods disclosed in the Diab

application fail to convey to a person of ordinary skill in the art that Diab had possession

of the two limitations when he filed his application.

A. Assuming that s and n are Uncorrelated

2008-1577 6

With respect to the first limitation, the claim language at issue is as follows:

“using said matrix to determine ra, by assuming s and n are uncorrelated; and

determining said saturation from ra.“

In support of his argument, Yorkey relies upon the Declaration of his expert, Dr.

Elvir Causevic (“Causevic”), who argued that:

[I]n determining ra using a matrix, Diab makes reiterative calculations and

then selects the calculation that minimizes the correlation between s and

n. The action and signal processing steps of minimization of correlation

are different from assuming the two values (s and n) are already

uncorrelated before doing the signal processing.

Moreover, argues Causevic:

To obtain ra and rv, an exhaustive scan is executed for a good cross-

section of possible values for ra and rv …. The minimum of the correlation

function is then selected and the values of ra and rv which resulted in the

minimum are chosen as ra and rv.

Causevic dilated considerably on the argument that the specification’s disclosure

reveals a method of minimizing correlation, rather than assuming that s and n are

simply uncorrelated, and concludes:

To a person of ordinary skill in the art, performing a scan of 20-50 values

is entirely different from a priori assuming that s and n are uncorrelated.

When assuming that s and n are uncorrelated, a person of ordinary skill in

the art would recognize that no iterative calculation is involved. No effort

to determine the minimum degree of correlation is involved. On the other

hand, scanning for 20-50 values assumes that there is a correlation and

uses the iterative process to find the minimum correlation. Accordingly,

Diab’s iterative signal processing step of minimizing a correlation

described in their approach is a different approach from assuming that two

values (s and n) are uncorrelated, as set forth in claims 16-18 and 21.

(emphasis in original).

The Board was unconvinced. Citing the Declaration of Dr. Gail Baura, Diab’s

expert witness, the court noted that the specification of the Diab application described

2008-1577 7

the limitation “at least four different times in at least four different ways in two

embodiments ….” The Board found that, on its face, the Diab application repeatedly

described embodiments in which it determined that s and n are uncorrelated. For

example: the Diab application contains the description:

[W]here s1 and n1 are at least somewhat (preferably substantially)

uncorrelated and s2 and n2 are at least somewhat (preferably

substantially) uncorrelated.

(emphases in Board’s original). The Board found that the description quoted above

would have described, by virtue of the phrase “at least … (preferably substantially)

uncorrelated” an embodiment in which s1 and n1 are completely uncorrelated. This,

found the Board, was consistent with Baura’s testimony that: “It is clear that in assuming

s and n to be [at least somewhat] ‘preferably substantially’ uncorrelated, the ideal

constraint would be that s and n have no correlation.”

The Board relied heavily on Baura’s testimony, finding her to be a more credible

witness than Causevic. The Board criticized Causevic’s testimony for averring that “a

person of ordinary skill in the art would recognize that no iterative calculation was

involved”, without producing any reason why this should be so.

We defer to the Board’s findings concerning the credibility of expert witnesses.

See Velander v. Garner, 348 F.3d 1359, 1371 (Fed. Cir. 2003) (“It is within the

discretion of the trier of fact to give each item of evidence such weight as it feels

appropriate”). Thus the Board was well within its discretion to give more credibility to

Baura’s testimony over Causevic’s unless no reasonable trier of fact could have done

so.

2008-1577 8

At first glance, equating the term “substantially uncorrelated” with “uncorrelated”

might be likened to equating the term “substantially not pregnant” with “not pregnant.”

However, correlation, like any other mathematical term of art, is a statistical function

wherein the significance of the relationship is, in effect, arbitrarily decided. For

example, the standard confidence level of p < 0.05 indicates at least a 95% probability

that a significant statistical relationship does not exist between two sets of values, and

that 95% probability limit (not 94% or 96%) is generally (but arbitrarily) accepted as

definitive of statistical significance. In the instant appeal, “substantially uncorrelated”

could be synonymous with “statistically significantly uncorrelated”, which would in turn

be, by definition, synonymous with “uncorrelated.” Although such a value is described

by the Diab application as being obtained by a process of iterative calculation, finding

the values of s and n that are substantially uncorrelated (and ideally “statistically

significantly uncorrelated”) is a necessary preliminary step prior to the ensuing

computation.

Furthermore, in addition to the language of the Diab application quoted above,

the application similarly states, on pages 101-02, that:

In order to determine ra and rv in accordance with this implementation, the

energy in the signal s2 is maximized under the constraint that s2 is

uncorrelated to n2. Again, this implementation is based upon minimizing

the correlation between s and n ….

Again, if minimizing the correlation between s and n forms the basis for the ensuing

constraint of non-correlation between s2 and n2, then the optimal results will be obtained

when the correlation between s and n is at a minimum, below statistical significance, or

“uncorrelated.”

2008-1577 9

Given the deference that we are required to show to the Board’s evaluation of the

credibility of Baura over Causevic, and reviewing her declaration testimony, we find that

the Board’s ruling that the Diab application possessed the limitation that s and n are

assumed to be uncorrelated is supported by substantial evidence in the record and we

therefore affirm the Board’s decision in this respect.

B. That the Signal be Expressed as a Matrix Solved for ra.

The Board likewise found that Baura was more credible than Causevic with

respect to the written description of the limitation “expressing said representations as a

matrix.” Causevic acknowledges the use of a matrix in the embodiment described by

Diab relating to ra s + rv n. This matrix is used to determine ra by finding the minimum of

the correlation, and appears as follows:

Sred ra rv s2

=

SIR 1 1 n2

However, Causevic contends that the second embodiment’s description of a

“further implementation to obtain ra and rv” does not explicitly refer to the matrix depicted

above relating to ra s + rv n. The Board noted, however, that this observation was not

accompanied by any meaningful discussion as to the actual text of Diab’s disclosure.

Page 101 of the Diab application states:

In a further implementation to obtain ra and rv, the same signal model set

forth above is again used. In order to determine ra and rv in accordance

with this implementation, the energy in the signal s2 is maximized under

the constraint that s2 is uncorrelated with n2.

2008-1577 10

The pages of the Diab application immediately preceding the quoted text, beginning on

page 98, are contained within a section entitled “Alternative Determination of

Coefficients ra and rv.” This section begins with a series of equations defining the

coefficients ra and rv (Eq. 89-91). The text then sets forth a method for the

determination of ra and rv by determining the minimum (preferably none) correlation

between sk and nk that can be determined (where k = 2) (Eq. 93). The text continues:

Minimizing this quantity often provides a unique pair of ra and rv if the noise

component is uncorrelated to the desired signal component. Minimizing

this quantity can be accomplished by solving Equations (90) and (92) for

s2 and n2, and finding the minimum of the correlation for possible values of

ra and rv. Solving for s2 and n2 provides the following [matrix equation].

The text of the Diab application then recites the two-by-two matrix recited above. The

text then describes further refinements of the model, inverting the matrix and solving for

s2 and n2, and suggesting the use of a Blackman Window as the preferred embodiment

for minimizing the correlation of s2 and n2.

The Board gave more credence to Baura’s testimony with respect to this point.

Baura points out the explicit language describing “the same signal model” disclosed for

the first embodiment (in which the matrix above is employed) as being the one for the

“further implementation to obtain ra and rv.” Moreover, according to Baura:

It is my opinion that this is referring to the signal model of the first

embodiment. It makes sense that the signal model referred to as “set

forth above” would refer to the first embodiment model because it

immediately precedes the above-quoted statement.

The Board found that Causevic’s failure to state what mathematical methodology,

other than the matrix, Diab’s disclosure would have reasonably conveyed to a skilled

artisan for the “further implementation” embodiment was fatal to Yorkey’s motion.

Likewise Yorkey’s failure to point to any other factual or legal basis for contending that

2008-1577 11

the absence of an undefined alternative function also necessitated the Board’s holding

that he had failed to meet his burden.

Given that substantial evidence supports the Board’s conclusions, we affirm the

Board’s finding that Yorkey failed to meet his burden of showing that the limitation

“expressing said representations as a matrix” of claims 16-18 and 21 of the Diab

application is not supported by a written description in violation of 35 U.S.C. § 112,¶ 1.

II. Yorkey’s Reduction to Practice

Yorkey next argues that the Board erred in holding that he failed to establish a

prima facie case that he had reduced Count 1 to practice prior to Diab’s benefit date of

October 7, 1994. Whether an invention has been reduced to practice is a question of

law based on underlying facts. Henkel Corp. v. Procter & Gamble Co., 560 F.3d 1286,

1288 (Fed. Cir. 2009). Accordingly, the Board's ultimate conclusion of reduction to

practice is reviewed de novo, while its underlying factual findings are reviewed for

substantial evidence. Henkel Corp. v. Procter & Gamble Co., 485 F.3d 1370, 1374

(Fed. Cir. 2007). Substantial evidence “is more than a mere scintilla. It means such

relevant evidence as a reasonable mind might accept as adequate to support a

conclusion.” Consol. Edison Co. v. NLRB, 305 U.S. 197, 229 (1938).

“In order to establish an actual reduction to practice, the inventor must prove that:

(1) he constructed an embodiment or performed a process that met all the limitations of

the interference count; and (2) he determined that the invention would work for its

intended purpose.” Cooper v. Goldfarb,154 F.3d 1321, 1327 (Fed. Cir. 1998). The

inventor must also “contemporaneously appreciate that the embodiment worked and

2008-1577 12

that it met all the limitations of the interference count.” Id. With the exception of very

simple inventions (which pulse oximetry is manifestly not), demonstration that the

invention works for its intended purpose requires testing. Mahurkar v. C.R. Bard, Inc.,

79 F.3d 1572, 1578 (Fed. Cir. 1996). As the junior party to the interference, Yorkey had

the burden of proof of establishing actual reduction to practice by a preponderance of

the evidence. 37 C.F.R. § 41.121(b) & 41.207(a)(2); see also Bosies v. Benedict, 27

F.3d 539, 541 (Fed. Cir. 1994). 3

Count 1, with respect to the Yorkey patent, consists of claim 1, which reads:

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

comprising the steps of:

irradiating said patient with electromagnetic radiation of two discrete,

different wavelengths;

sensing an intensity of said radiation for each of said wavelengths after it

passes through a portion of said patient to produce first and second

intensity signals including motion components; and determining said

saturation by mathematically manipulating said first and second intensity

signals without subtracting said motion components and with the

assumptions that

i) an amount of motion is the same at the same time for each of said

intensity signals, and

ii) the motion components of said intensity signals are proportional to

one another.

Yorkey’s principal evidence of reduction to practice is a computer program, two

versions of which (v. 1.0 and 1.1) were archived on June 18 and 23, 1993, respectively.

The two versions are identical insofar as the method of Count 1 is concerned. The

3

The Board did not consider, and Yorkey does not argue on appeal that he conceived

of the claimed invention prior to Diab’s priority date and exercised reasonable diligence

in reducing the invention to practice from conception to his date of constructive

reduction to practice.

2008-1577 13

software has nothing to do with the first two steps of Count 1, i.e., irradiating a patient

with electromagnetic radiation of two discrete, different wavelengths and sensing an

intensity of the radiation for each of the wavelengths after it passes through a portion of

the patient to produce first and second intensity signals including motion components.

Rather, the program receives the patient data resulting from those two steps as input.

Two sources of data were used by the program; some data were collected from

patients in hospitals and other data were collected from in-house clinical studies known

as “breathe-down” tests. 4 Yorkey argues that the Board erroneously discredited the

evidence collected in hospitals because Yorkey did not submit evidence from anyone

who was involved in the collection of the hospital data who could corroborate that the

data was collected in accordance with the methods described in the Count. Specifically,

the Board noted that it was “uncertain and speculative” whether the data charts referred

to in Yorkey’s motion corresponded to the data collected by Yorkey’s research

associate, Clark R. Baker (“Baker”) in the breathe-down tests, or whether it was

gathered from the hospital patients. The Board found this purported ambiguity

significant in that it could not assume that the data, if collected from the hospital

patients, was generated via the first two steps recited in the Count and included a

motion component.

Yorkey argues that, on the contrary, testimony by Baker demonstrated that the

data collected both at hospitals and in the in-house breathe-down tests identified the

4

In the breathe-down tests, volunteer subjects breathed a gas mix, administered by an

anesthesiologist, containing sub-atmospheric concentrations of oxygen to decrease

their blood oxygen saturation levels.

2008-1577 14

model of oximeter used to collect the data, the Nellcor N-200 oximeter. In fact, Baker

testified that:

I generated a series of charts, illustrating the oxygen saturation values

computed by (a) the various saturation algorithms we had implemented

and (b) the pulse oximeter that had been used to collect the data (e.g., the

Nellcor N-200).

And indeed, the charts do show a line labeled N-200, which could reasonably be

apprehended as corresponding to data from the Nellcor-200 oximeter. Moreover, the

Yorkey patent illustrates oximetry data showing two separate wavelengths, although the

model of the oximeter is not identified, nor did Yorkey provide any direct evidence that

the Nellcor N-200 model oximeter uses two wavelengths

The Board clearly erred in finding that the issue of whether the data referred to in

Baker’s testimony was derived from hospital patient data or from the breathe-down tests

creates a fatal ambiguity in Yorkey’s claim of reduction to practice. Baker testified that

“Nellcor’s clinical engineers had collected patient data in hospitals. The patients had

been moving during some aspect of the data collection.” (emphasis added). Although

Baker may have had no direct knowledge that the patients were actually moving during

the tests conducted by Nellcor’s engineers, such direct knowledge is not necessary.

See, e.g., Cooper v. Goldfarb, 154 F.3d 1321, 1330 (Fed. Cir. 1998) (“In order to

corroborate a reduction to practice, it is not necessary to produce an actual over-the-

shoulder observer.”). Furthermore, Baker averred that he had observed, via a manual

examination of the regularity of the oximetry data, whether the changes in value were

attributable to motion or physiological changes. By comparing the saturation from

oximetry probes collecting data simultaneously at different sites on the body, Baker was

able to determine whether a change in the blood saturation data was due to induced

2008-1577 15

motion or to other physiological causes. In short, Baker was able to determine whether

the data included a motion component by inspection of the collected data, regardless of

whether the data was derived from hospital patients by Nellcor engineers or from the

breathe-down test volunteers.

Moreover, Baker testified that the data used was derived from pulse oximeters

(i.e., the Nellcor N-200). The Yorkey patent describes oximeters as typically emitting

two wavelengths of light. Yorkey patent at Col. 2, ll. 2-4 (“The oximeter relies on

mathematical analysis of the reading at two different wavelengths”). Furthermore, the

Yorkey software requires input from two discrete wavelengths, red and infrared, to

complete its saturation analysis. We conclude therefore, that the issue of whether the

data presented by Yorkey as evidence of his reduction to practice was derived from

hospital patients or from breathe-down volunteers does not undermine Yorkey’s claim

that he had successfully reduced to practice his invention prior to Diab’s benefit date of

October 7, 1994.

The Board next found that the two versions of the computer program archived by

Yorkey in 1993 were thirty-six and thirty-seven pages long respectively, and neither

version was accompanied by an explanatory flow chart tracking the operational flow of

the program. The Board found the program not to be self-explanatory, and objected to

the notion that it should be required to undertake an independent determination of what

each line of code means.

In his priority motion, Yorkey contended that the program was “based on” his “eta

methodology”, troubling the Board with what precisely “based on” might mean. The

Board found that Yorkey had explained what the eta methodology is with sufficient

2008-1577 16

clarity, but had failed to show that the computer program implements or executes it. In

particular, the Board found that Yorkey had not specifically identified in the software: (1)

the input interface; (2) the output interface; or (3) the sequence of computational steps

and calculations which transforms the input patient data to the determined oxygen

saturation output. In other words, the Board found that Yorkey had made an inadequate

showing as to how the computer program implements the central equation of the eta

methodology.

Specifically, the Board found that Yorkey’s only argument supporting the

implementation of the eta methodology equation in his motion comprised the following

lines:

The software set forth code for two or more wavelengths, taking the

logarithm of each representation of the first and second intensity signals,

and using a high pass filter to provide the functionality of taking the

derivative of the logarithm.

According to the Board, this conclusory statement that assumptions were made in

writing the program was inadequate and unpersuasive.

Yorkey takes umbrage at the Board’s finding, responding that it was both based

on a faulty premise and irrelevant. According to Yorkey, his testimony, and that of

Baker, establishes that Count 1’s assumptions were taken into account when the

software code was written. The lines of code, according to Yorkey, are the embodiment

of the assumptions and corroborate Yorkey’s and Baker’s testimony.

Specifically, Yorkey maintains that he and Baker explained in detail how the

software works to implement the eta methodology. He contends that the following lines

of code indicate that red and infrared wavelengths were to be used by the software, with

a placeholder for other possible wavelengths:

2008-1577 17

struct LED

long

IR,

Red,

Other

The software subsequently log-converts these signals and then differentiates the

infrared- and red-wavelength signals using a differential high pass filter — the

implementation enabled by the mathematical equation of the intensity function and the

assumptions concerning motion as described in the following lines:

”if (hardware Log = = FALSE)

*newir = (float) log ((double) *newir);

*newred = (float) log ((double) *newred)"

"*newir = hpf (*newir, 0);

*newred = hpf (*newred, 1)”

These lines of code, according to Yorkey, followed by saturation determination, embody

Count 1’s assumptions in the form of log conversion and differentiation calculations on

both red- and infrared-wavelength signal intensities.

Yorkey further argues that he and Baker identified in the code the ratio-of-ratios

(“ROR”) saturation calculation. Yorkey argued to the Board that Baker’s notation on the

test results that: “the eta sat calculator used here was incapable of calculating

sat[uration]s for which the ratio-of-ratios approached or exceed 1.0” indicated

application of the eta methodology. According to Yorkey, this characteristic of the ROR

method is referred to in the Yorkey patent. See Yorkey patent at Col. 7, ll. 34-37.

Yorkey then quoted a portion of the code demonstrating the use of the ROR:

if (RoR) < (float)RoRMax)

sat = (betas.betaRred - RoR * betas.betaRir) /

(betas.debetair * RoR - betas.dbetared);

else

sat = - 1;

return (sat);13

2008-1577 18

Importantly, Yorkey’s explanations of the computer program are found in his declaration

and are corroborated by Baker’s declaration.

According to Yorkey, the Yorkey patent teaches that, following logarithmic

conversion and differentiation, oxygen saturation can be calculated by mathematically

manipulating the intensity signals, without subtracting an independently monitored

motion signal, using matrix algebra. The Yorkey patent teaches:

For example, to account for motion and noise, we can modify equation (1)

by multiplying by a time varying function η(t) representing wavelength-

independent motion or noise. This gives the following equation:

…

We can then solve for s using the same steps as used above.

First, we take the logarithm:

…

Next, we differentiate with respect to time:

…

Then, we determine the ratio of Red to IR:

…

Now if d log η/dt is large compare to the other terms the ratio of ratios will

be driven towards unity, driving s towards a wavelength-dependant

constant. So because in this model optical coupling due to motion appears

identically in both wavelengths, its presence drives the saturation to this

wavelength-dependant constant.

The present invention thus allows a calculation of blood oxygen saturation

by mathematically recognizing the motion signal.

Yorkey patent at Col. 5 ll. 23-53 (equations omitted). The term η(t) is the time-

dependent motion signal Yorkey argues is the basis of the eta methodology, which

determines the ROR without subtracting the motion signal. And, as explained by the

Yorkey patent’s teaching above, this forms the basis of a calculation of oxygen

saturation. Yorkey argues that his testimony, and Baker’s, thus established a prima

2008-1577 19

facie case that Count 1 had been successfully reduced to practice and that the Board’s

contrary finding is erroneous. 5

We find that Yorkey met his burden of establishing a prima facie case of actual

reduction to practice. The Board acknowledged that the first claim and its limitation

were met by Baker’s testimony and data with respect to the breathe-down tests.

Moreover, the “two discrete wavelengths” limitation is met by the software code, which

requires inputs from infrared (“IR”) and red (“Red”) wavelengths as well as possible

other (“Other”) wavelengths.

Finally, the limitation of:

[D]etermining said saturation by mathematically manipulating said first and

second intensity signals without subtracting said motion components and

with the assumptions that

i) an amount of motion is the same at the same time for each of said

intensity signals, and

ii) the motion components of said intensity signals are proportional to one

another.

is met by Yorkey’s explanation of the code with respect to the determination of the

ROR, which is in turn based upon the eta methodology, which implicitly meets

limitations i and ii, i.e., because η(t) is only a time-dependent factor, and is used to

determine the ROR, it must be the same for each of the signals and proportionate to

them. Therefore, Yorkey has met his burden of establishing a prima facie case showing

that his invention met the limitations of Count 1 and worked successfully for its intended

purpose.

5

Yorkey argues that the method was successful in measuring blood oxygen saturation,

noting Baker’s comment of “eta wins” accompanying the data resulting from the testing.

The Board does not contest that fact.

2008-1577 20

For the foregoing reasons, we reverse the Board’s rulings that Yorkey failed to

establish a prima facie case of actual reduction to practice of Count 1 prior to the Diab

application’s benefit date of October 7, 1994. We consequently remand this case to the

Board for further proceedings consonant with this order.

CONCLUSION

For the reasons set forth above, we affirm the Board’s ruling that the asserted

claims of the Diab application meet the written description requirement of § 112 and its

denial of Yorkey’s motion. However, we reverse the Board’s finding that Yorkey failed

to establish a prima facie case of actual reduction to practice of Count 1 prior to the

Diab application’s benefit date of October 7, 1994. We therefore remand this case to

the Board for further proceedings consonant with this order.

AFFIRMED IN PART, REVERSED IN PART, AND REMANDED

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