CPLRG™ 0043 - Yorkey v. Diab - Apr. 7, 2010

Yorkey v. Diab, 610 F.3d 1297 (Fed. Cir. 2010) (MICHEL, Gajarsa & Kendall, district judge)Yorkey477

MAJOR ISSUES: interference in fact; interference; claim interpretation; PTO broadest reasonable construction of claims

COMMENT.  This is one of two cases, which, confusingly, have the same name and date.  The other case is: Yorkey v. Diab, 610 F.3d 1279, CPLRG 0042 (Fed. Cir. 2010).  https://www.chisum.com/cplrg-guides/0042#more-623
     The two Yorkeys are separate appeals from two related interferences (471 and 477) in the Patent and Trademark Office (PTO).
     This Yorkey appeal (the 477 interference) resolved an issue of whether there was an “interference in fact.”  An interference-in-fact inquiry is one into whether the parties’s distinct claims are for the same patentable invention.  If there is no interference-in-fact, there is no basis for an interference proceeding to determine who was the first to invent.  Both parties may be able to have valid patents on their distinct inventions.
     As this case illustrates, existence of an interference hinges on the proper interpretation of the parties’ claims.  Before the PTO, including in an interference, the operative claim interpretation standard is that claims must be given the broadest reasonable construction.  A broad construction tends to favor finding an interference in fact, but it can raise issues whether a claim, so construed, is supported.

1. BLOOD OXYGEN CONCENTRATION MEASUREMENT. As explained in CPLRG 042, both interferences were between a patent (by a junior party Yorkey) and an application (by a senior party Diab).  See U.S. Pat. 5,645,060. USPatNo5645060
     a. The interference comprised a single count and, as corresponding claims, Yorkey’s claim 6 and Diab’s claim 39.
     b. The junior party Yorkey moved for judgment of no interference-in-fact.  Alternatively, assuming that a broad construction of the Diab claim 39 showed an interference-in-fact, the junior party moved for a judgment that the Diab claim 39 failed for lack of written description support (35 U.S.C § 112/6).
     c.  The PTO Board denied both motions.
     d. The Federal Circuit held that the Board did not err.  The Board properly gave the senior party Diab’s claim 39 a broad construction.  The claim, as broadly construed, anticipated the junior party’s claim 6.  The senior party’s specification provided a sufficient written description of the broadly construed claim.

2. INTERFERENCE IN FACT; BURDEN OF PROOF; STANDARD.  The junior party Yorkey bore the burden of showing, by a preponderance of the evidence, that the two claims did not interfere-in-fact.  37 C.F.R. § 41.202(d); In re Garner, 508 F.3d 1376, 1377 (Fed. Cir. 2007).  An interference-in-fact exists if a party’s claim anticipates or renders obvious the other party’s claim–or vice versa.  37 C.F.R. § 41.203(a).  Anticipation entails construing a claim and comparing the claim to a prior art reference to determine whether the reference shows every limitation of the claim.  In re Crish, 393 F.3d 1253, 1256 (Fed. Cir. 2004).

3. PULSE OXIMETRY;  The inventions claimed in the patent and application concerned “pulse oximetry,” the noninvasive measurement of blood oxygen by the analysis of physiological signals detected from multi-wavelength radiations projected through a patient.
     a. MOTION-INDUCED NOISE; AMBIENT INTERFERENCE WITH DETECTION OF SIGNALS.  A problem in the prior art was motion-induced “noise” that interfered with the detection of the relatively weak physiological signals.
     b. UNLIKE PRIOR ART, NO DIRECT SUBTRACTION OF MOTION-INDUCED NOISE FROM SIGNAL.  Unlike prior art solutions to the problem, the claimed inventions did not rely on “the direct subtraction of noise from the signal.”
     c. TWO SIGNALS; RED AND INFRARED WAVELENGTHS.  The inventions involving measuring two separate intensity signals, one from transmitted light in red wavelengths, one from infrared wavelengths.
     d. TWO ASSUMPTIONS.  The inventions relied on two assumptions.
           i. The first assumption was that the amount of actual motion was the same for both signals.
          ii. The second was the “the motion component portions of the detected signals are proportionate.”

4.  THE METHODS; MEASURING SATURATION; FIRST AND SECOND INTENSITY SIGNALS. The pulse oximetry methods of the patent and application entailed, inter alia, measuring the saturation of oxygen in blood by irradiating a patient with at least two discrete wavelengths (e.g.,. red and infrared) and sensing the radiation for each wavelength after it passes through the patient to produce first and second intensity signals.

5. PRINCIPAL ISSUE: LAST TWO LIMITATIONS IN EACH CLAIM.  On appeal, the “principal issue” stemmed from the last two limitations of the parties’ claims.
     a. JUNIOR PARTY CLAIM 6; THREE WAVELENGTHS; THREE INTENSITY SIGNALS; FUNCTIONS OF SATURATION. In reciting the method, the junior party Yorkey’s claim 6 required, inter alia, sensing three wavelengths to produce a first, second and third intensity signal and representing each signal as a function of patent blood oxygen saturation.
          i. PENULTIMATE LIMITATION.  In its penultimate limitation, claim 6 required:  “solving the three functions to obtain a value for said saturation.” (Emphasis by court).
          ii. ULTIMATE LIMITATION.  In its ultimate limitation, claim 6 required:  “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.’ ” (Emphasis by court).
     b. SENIOR PARTY DIAB’S CLAIM 39.  The senior party Diab’s claim 39 differed in its penultimate and ultimate limitations.
          i. PENULTIMATE LIMITATION.  In its penultimate limitation, claim 39 required: “solving the functions to obtain a value for said saturation.” 
          ii. ULTIMATE LIMITATION.  In its ultimate limitation, claim 39 required:  ” `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 determining said saturation from said approximation of said first and second intensity signals.’ ”

6. CLAIM CONSTRUCTION  RESOLVING INTERFERENCE IN FACT.  On appeal, the parties agreed that the issue of interference-in-fact turned on the correctness of the Board’s construction of the senior party Diab’s claim 39.
     a. JUNIOR PARTY: SENIOR PARTY’S CLAIM 39 USED ONLY TWO FUNCTIONS TO OBTAIN SATURATION WHEREAS ITS CLAIM 6 REQUIRED DIRECT USE OF ALL THREE FUNCTIONS.  To the Board, relying on its expert’s testimony, the junior party argued that Diab’s claim 39 used only two functions to obtain saturation.  It used the third signal only as a reference and to approximate a portion of the first and second signals.  In contrast, it argued, the junior party’s claim 6 required direct use of all three functions to obtain saturation values.
     b. SENIOR PARTY.  The senior party’s expert disagreed, arguing that “solving the three functions” in claim 6 did not differ from “solving the functions” in claim 39
          i. CLAIMS DO NOT EXCLUDE FURTHER STEPS OR REQUIRE DIRECT CALCULATION OF SATURATION.  The expert argued that neither claim excluded further steps or required direct calculation of saturation.
          ii. DIAB CLAIM 39: THREE FUNCTIONS USED CONSECUTIVELY; NO SUBSTANTIVE DIFFERENCE.  The expert argued that the Diab claim 39 used the three functions in consecutive calculations and that there was no substantive difference between solving the functions together and solving them consecutively.
     c. BOARD CREDITS SENIOR PARTY’S EXPERT.  The Board agreed with the senior party because, inter alia, its expert’s testimony was more consistent with the claims language.
          i. NO LANGUAGE COMPELLING NARROW CONSTRUCTION; BROADEST REASONABLE CONSTRUCTION.  The Board noted that the junior party did not cite any language in the Diab claim or specification compelling the narrower construction.  It applied the settled rule requiring that the PTO give claims their broadest reasonable construction.
          ii. DAUB CLAIM 39 APPROXIMATION STEP: NOT EXCLUDED BY YORKEY CLAIM 6; JUST A STEP IN SOLVING THE THREE FUNCTIONS.  The Board noted that the “approximation step” required by the Diab claim 39’s ultimate limitation was not excluded by Yorkey’s claim 6.  Approximation was just a step in solving the three functions.
     d. APPEAL.  On appeal, the junior party Yorkey argued that the Board erred.  It argued that the Diab claim 39 could not be construed as requiring “solving the three functions to obtain a value for saturation,” as Yorkey’s claim 6 expressly required in its penultimate limitation. This was because, in Diab claim 39, the third signal “merely serv[ed] as a noise reference to be subtracted.”   The argument lacked merit.
         i. IN DAUB, THREE FUNCTIONS ARE TIME DEPENDENT AND INCLUDE BOTH A CONCENTRATION FACTOR AND A NOISE COMPONENT.  As shown in the Daub specification, all the functions were time dependent and included both a concentration factor and a noise component.
         ii. SEQUENTIAL SOLUTION OF ALL THREE FUNCTIONS.  The Daub specification taught “each function is solved sequentially to obtain a value for oxygen saturation.” 
        iii. ALL THREE FUNCTIONS REPRESENT A SIGNAL AS FUNCTION OF SATURATION; SEQUENTIAL SOLUTION OF FUNCTIONS: REQUIRED TO OBTAIN A FINAL VALUE OF 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.”

7. WRITTEN DESCRIPTION.  The junior party Yorkey argued that the Diab claim 39, construed to cover solution of all three signal functions, lacked written description support in the Daib’s specification.  The argument lacked merit.
     a. DESCRIPTION OF A THIRD SIGNAL.  The Daib specification described the generation of three signals in terms of an equation.  Each equation, as a result of an operation, was a “function.”
     b. THIRD SIGNAL NOT LIMITED TO NOISE COMPONENT.  Contrary to the junior party’s argument, the third function was not limited to motion-induced noise.  It was identical to the other two functions except for a varying wavelength.
     c. SPECIFICATION: APPROXIMATES A PORTION OF FIRST AND SECOND SIGNALS BASED ON THIRD SIGNAL; VALUE BASED ON APPROXIMATION.  The court noted: “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 S( [lambda] red1)(t) and S([lambda] red2)(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.”
      d. LANGUAGE CONVEYS POSSESS TO ARTISAN OF ORDINARY SKILL; LOCKWOOD (1997).  The court concluded: “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 1565, 1571-72 (Fed. Cir. 1997).”

1. On interference-in-fact, see Chisum Patent Law Digest 1632; Chisum on Patents 10.09[4][b].

2. On the written description requirement, see Chisum Patent Law Digest 2200; Chisum on Patents 7.04.

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