CPLRG™ 0042 - Yorkey v. Diab - Apr. 7, 2010

Yorkey v. Diab, 610 F.3d 1279 (Fed. Cir. 2010) (MICHEL, Gajarsa & Kendall, district judge)Yorkey471

MAJOR ISSUES: written description; actual reduction to practice; PTO interferenceCOMMENT.  This is one of two cases, which, confusingly, have the same name and date.  The other case is: Yorkey v. Diab, 605 F.3d 1297, CPLRG 0043 (Fed. Cir. 2010).
      The two Yorkeys are separate appeals from two related interferences (471 and 477) in the Patent and Trademark Office (PTO).
      Interferences exist, historically, to resolve priority conflicts between or among competing claimants to the same invention.  Though currently linked to the United States first-to-invent priority principle, interferences can and often do resolve issues, such as sufficiency of disclosure under the “written description requirement” and patentability, that are independent of that principle.  These issues would remain even if the United States converts to a first-to-file priority principle.
     This Yorkey appeal (the 471 interference) resolved a written description issue as well as a classic first-to-invent issue: actual reduction to practice.  Written description issues arise regularly in the context of determining patentability for application and patent claims.   Written description issues are also common in interferences because a party may copy the claims from another party or at least craft claims with a view to provoking and winning an interference.  Claim language inspired by another party’s disclosure can, understandably, raise questions about whether the party’s specification discloses the substance of the subject matter covered by the claim language.

1. BLOOD OXYGEN CONCENTRATION MEASUREMENT.  Both interferences were between a patent (by a junior party Yorkey) and an application (by a senior party Diab) and concerned blood oxygen concentration measurement.  See U.S. Pat. 5,645,060.USPatNo5645060
    a. PULSE OXIMETRY.  The inventions claimed in the patent and application concerned “pulse oximetry,” the noninvasive measurement of blood oxygen by the detection and analysis of physiological signals.
     b. PROBLEM: MOTION-INDUCED NOISE.  A problem in the prior art was motion-induced “noise” that interfered with the detection of relatively weak physiological signals.
     c. SOLUTION NOT USING DIRECT SUBTRACTION .  Unlike prior art solutions to the problem, the claimed inventions did not rely on “the direct subtraction of noise from the signal.”  The inventions involving measuring two separate intensity signals, one from transmitted light in red wavelengths, one from infrared wavelengths.  The inventions relied on two assumptions.  The first assumption was that the amount of actual motion was the same for both signals.  The second was the “the motion component portions of the detected signals are proportionate.”

2. WRITTEN DESCRIPTION:  DID SENIOR PARTY’S PRIORITY APPLICATION SUPPORT TWO LIMITATIONS?  The junior party moved to have the senior party’s claims corresponding to the interference counts denied for lack of written description because, allegedly, the senior party’s application did not sufficiently describe two limitations.  The Board denied the motion, finding that the limitations were sufficiently described.  HELD: substantial evidence supported the Board’s findings on written description because, inter alia, it permissibly credited one expect’s declaration over another expert’s contrary declaration.
     a. FIRST DISPUTED LIMITATION.  The first disputed limitation in the applicant’s claims required that a matrix be used to determine a ratio on arterial oxygen saturation (“r(a)”) by assuming that “s” and “n” are “uncorrelated.” The symbol “s” is “the actual signal (light attenuation as a function of arterial oxygen saturation) to be measured.”  The symbol “n” is the “motion-induced noise.”
          i. The applicant’ specification described embodiments in which “s” and “n” were “at least somewhat (preferably substantially) uncorrelated.”
          ii. In a declaration, the patent owner’s expert Causevic opined that the applicant’s specification disclosed making reiterative calculations and selecting the calculation that minimized the s-n correlation.  The expert opined that a person of ordinary skill would deem the reiterative calculation as a different approach from an assumption of no correlation.  With the latter, no calculation would be required.
          iii. In a declaration, the applicant’s expert Baura opined that the applicant’s specification clearly conveyed that an ideal constraint would be no correlation.
          iv. The Board found the applicant’s expert Baura to be more credible than the patent owner’ expert.  A court must defer to the PTO Board’s credibility determination.
          v. EQUATING “SUBSTANTIALLY UNCORRELATED” WITH “UNCORRELATED”; LIKE “SUBSTANTIALLY NOT PREGNANT” EQUAL TO “NOT PREGNANT”?  “At first glance, equating the term `substantially uncorrelated” with `uncorrelated” might be likened to equating the term `substantially not pregnant’ with `not pregnant.’ ”
               A. “However, correlation, like any other mathematical term of art, is a statistical function wherein the significance of the relationship is, in effect, arbitrarily decided.”
               B. “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.”
               C. “In the instant appeal, `substantially uncorrelated’ could be synonymous with `statistically significantly uncorrelated’, which would in turn be, by definition, synonymous with `uncorrelated.’ ”
          vi. The applicant’s disclosure of iterative calculation did not detract from a finding of disclosure support for “no correlation.”   This was because “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.”

     b. SECOND DISPUTED LIMITATION.  The second disputed limitation in the applicant’s claims required “expressing said representations as a matrix.”
          i. The patent owner’s expert Causevic agreed that the first embodiment in the applicant’s specification, which concerned “r(a) s + r(v) n”, used a matrix.  However, the expert opined that a second embodiment, which concerned “further implementation to obtain r(a),” did not explicitly refer to the matrix in the first embodiment.
           ii. The applicant’s expert Baura opined that the language of the second embodiment on “further implementation” of the first embodiment included the use of the matrix.
          iii. Again, the Board credited the applicant’s expert over that of the patent owner.
          iv. The patent owner’s expert failed to explain what mathematical methodology, other than a matrix, would a skilled artisan assume to be used for the “further implementation” embodiment.

3. ACTUAL REDUCTION TO PRACTICE.  The senior party’s priority filing date was October 7, 1994.  The junior party’s priority filing date was June 14, 1995.  The junior party attempted to show a pre-filing invention date through an actual reduction to practice prior to October 7, 1994.  The PTO Board held that the junior party failed to make a prima facie case. The Federal Circuit reverses.  The junior party presented evidence in the form of the inventor’s testimony, corroborating testimony by an associate, and a computer program used to carry out the invention defined in the interference count.
     a. DATA GATHERED ACCORDING TO COUNT’S REQUIREMENTS.   The count defined a method.  The first step was to irradiate a patient with radiation of two wavelengths; the second step was to sense the radiation’s intensity to produce signals that included motion components; the third step was to make a determination by mathematical manipulation.  The junior party’s evidence showed the collection of data from two sources: patients in hospitals, and an in-house “breathe-down” test.  The Board found that the evidence was ambiguous as to which source data was gathered and, therefore, failed to show compliance with the count’s first two steps.  However, any ambiguity did not effect the adequacy of the junior party’s evidence.  The junior party presented testimony by the inventor’s associate that (i) both sources used a specified oximeter, which typically would emit two wavelengths, and (ii) examination of the data revealed that it included a “motion component”, as the count required.
     b. EXPLANATION OF COMPUTER PROGRAM.  The Board criticized the junior party for failing to provide a flow chart explaining how the computer program met the count’s limitations.  However, the junior party did explain how the program’s code was designed to implement the inventor’s “eta methodology,” which implicitly met the count’s limitation on a saturation determination by a signal manipulation without subtraction of motion components.

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

2. On actual reduction to practice as a facet of a pre-filing invention date and the related requirement of corroboration, see Chisum Patent Law Digest 1613, 1616; Chisum on Patents 10.06.

3. On interference procedure, including the copying of claims to provoke interferences, see Chisum Patent Law Digest 1633; Chisum on Patents 10.09[4].

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