DCT

1:09-cv-00080

Masimo Corp v. Philips Electronics North America Corp

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: Masimo Corp. v. Philips Electronics North America Corp., 1:09-cv-00080, D. Del., 05/12/2009
  • Venue Allegations: Plaintiff alleges venue is proper in the District of Delaware because Defendant Philips Electronics North America resides in Delaware and Defendant Philips Medizin Systeme Böblingen conducts substantial business in the United States and is subject to personal jurisdiction in the district.
  • Core Dispute: Plaintiff alleges that Defendant’s patient monitors incorporating "Fourier Artifact Suppression Technology" (FAST-SpO2) infringe a fourteen-patent portfolio related to signal processing for pulse oximetry.
  • Technical Context: The technology concerns pulse oximetry, a non-invasive medical diagnostic method used to measure blood oxygen saturation, a critical vital sign in patient monitoring.
  • Key Procedural History: The complaint is a First Amended Complaint for Patent Infringement. No prior litigation, licensing history, or post-grant proceedings involving the parties are mentioned in the complaint.

Case Timeline

Date Event
1991-03-07 U.S. Patent No. 6,002,952 Priority Date
1993-10-06 U.S. Patent No. 5,632,272 Priority Date
1997-05-27 U.S. Patent No. 5,632,272 Issue Date
1999-12-14 U.S. Patent No. 6,002,952 Issue Date
2000-12-05 U.S. Patent No. 6,157,850 Issue Date
2001-07-17 U.S. Patent No. 6,263,222 Issue Date
2001-12-25 U.S. Patent No. 6,334,065 Issue Date
2003-11-18 U.S. Patent No. 6,650,917 Issue Date
2004-03-02 U.S. Patent No. 6,699,194 Issue Date
2004-06-01 U.S. Patent No. 6,745,060 Issue Date
2004-08-03 U.S. Patent No. 6,770,028 Issue Date
2007-05-08 U.S. Patent No. 7,215,984 Issue Date
2009-02-10 U.S. Patent No. 7,489,958 Issue Date
2009-03-03 U.S. Patent No. 7,499,741 Issue Date
2009-03-24 U.S. Patent No. 7,509,154 Issue Date
2009-05-12 U.S. Patent No. 7,530,949 Issue Date
2009-05-12 Complaint Filing Date

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 5,632,272 - "Signal Processing Apparatus"

The Invention Explained

  • Problem Addressed: The patent addresses the difficulty of extracting a desired physiological signal (the primary signal portion) from a measured composite signal when it is corrupted by noise (the secondary signal portion), particularly when the noise overlaps in frequency with the desired signal, as is common with patient motion artifacts in pulse oximetry (’272 Patent, col. 1:44–56). Conventional filtering is ineffective in such cases, and correlation canceling methods require a noise reference signal that is often unavailable (’272 Patent, col. 1:56–65).
  • The Patented Solution: The invention proposes a method to derive a noise reference signal directly from two simultaneously measured composite signals (e.g., signals from red and infrared light). The method models the relationship between the primary and secondary portions of these two signals. This model allows the processor to generate a reference signal that is correlated to the noise but not the desired physiological data. This derived noise reference is then used in a correlation canceler to remove the noise from the original measured signal, yielding a "clean" physiological signal (’272 Patent, col. 3:25–4:14; FIG. 4a).
  • Technical Importance: This approach provided a method for improving the reliability of physiological monitoring, such as pulse oximetry, in the presence of motion-induced noise, a significant limitation of prior art devices (’272 Patent, col. 2:56–65).

Key Claims at a Glance

  • The complaint asserts infringement of "at least one claim" of the '272 Patent without further specification (Compl. ¶24). The first independent claim is Claim 1, a method claim.
  • Essential elements of Claim 1 include:
    • Processing at least two measured signals S₁ and S₂, each containing a primary signal portion (s) and a secondary signal portion (n).
    • The signals are modeled such that s₁=rₐs₂ and n₁=rᵥn₂.
    • Determining a value of coefficient rₐ which minimizes correlation between s₁ and n₁.
    • Processing at least one of the signals using the determined value for rₐ to significantly reduce n and form a clean signal.

U.S. Patent No. 6,002,952 - "Signal Processing Apparatus and Method"

The Invention Explained

  • Problem Addressed: Patient motion introduces artifacts into physiological measurements like pulse oximetry, creating an "undesired signal portion" (noise) that corrupts the "desired signal portion" (the plethysmographic wave), making it difficult to accurately determine physiological parameters (’952 Patent, col. 2:50–61).
  • The Patented Solution: The patent discloses a "signal scrubber" to remove the undesired signal portion. One embodiment involves transforming two measured signals (e.g., red and infrared) into the frequency domain. The processor then analyzes the ratio of these spectral signals to determine a "scrubber coefficient." This coefficient is then used by a "waveform scrubber" to generate an estimate of the desired signal portion, effectively removing the motion artifact (’952 Patent, col. 4:1–11; FIG. 12).
  • Technical Importance: The invention provides signal processing methods, including rule-based and transform-based techniques, to identify and remove motion artifacts, thereby enabling more robust pulserate and oxygen saturation measurements under challenging clinical conditions (’952 Patent, col. 4:47–56).

Key Claims at a Glance

  • The complaint asserts infringement of "at least one claim" of the '952 Patent (Compl. ¶30). The first independent claim is Claim 1, a method claim.
  • Essential elements of Claim 1 include:
    • Acquiring first and second measured signals, each having desired and undesired portions.
    • Determining a scrubber coefficient based on the signals.
    • Generating an estimate of the desired signal portion by inputting the measured signals and the scrubber coefficient into a waveform scrubber.
    • Determining a physiological parameter from the estimated desired signal portion.

U.S. Patent No. 6,157,850 - "Signal Processing Apparatus"

  • Patent Identification: U.S. Patent No. 6,157,850, "Signal Processing Apparatus", issued December 5, 2000 (Compl. ¶9).
  • Technology Synopsis: This patent describes signal processing techniques for physiological monitors, particularly pulse oximeters, to improve accuracy in the presence of noise. It discloses methods using a transform, such as a Fourier transform, to analyze measured signals and determine coefficients that relate the signals, enabling the isolation of the desired physiological information (’850 Patent, Abstract).
  • Asserted Claims: At least one claim (Compl. ¶36).
  • Accused Features: Philips products incorporating FAST-SpO2 technology (Compl. ¶36).

U.S. Patent No. 6,263,222 - "Signal Processing Apparatus"

  • Patent Identification: U.S. Patent No. 6,263,222, "Signal Processing Apparatus", issued July 17, 2001 (Compl. ¶10).
  • Technology Synopsis: This patent relates to a signal processor that uses a derived reference signal in a correlation canceler to remove motion artifacts from physiological signals. The invention describes generating a reference signal correlated to noise by processing two or more measured signals, and then using this reference to produce a clean signal representative of a physiological parameter like blood oxygen saturation (’222 Patent, Abstract).
  • Asserted Claims: At least one claim (Compl. ¶42).
  • Accused Features: Philips products incorporating FAST-SpO2 technology (Compl. ¶42).

Editor's Note: The complaint asserts twelve additional patents. In the interest of conciseness, capsule summaries for U.S. Patent Nos. 6,334,065; 6,650,917; 6,699,194; 6,745,060; 6,770,028; 7,215,984; 7,489,958; 7,499,741; 7,509,154; and 7,530,949 are omitted. These patents generally relate to further refinements and alternative embodiments of signal processing techniques for physiological monitors to improve noise and artifact cancellation.

III. The Accused Instrumentality

Product Identification

The accused instrumentalities are Philips' patient monitors incorporating "Fourier Artifact Suppression Technology" ("FAST-SpO2"), specifically including the IntelliVue line (MP20/30, MP40/50, MP60/70/80/90 monitors) and the Philips MMS X2 transport monitors (Compl. ¶21).

Functionality and Market Context

The accused products are physiological monitors used to measure patient vital signs, including blood oxygen saturation via pulse oximetry (Compl. ¶21). The complaint alleges these products incorporate a specific technology branded as FAST-SpO2, which suggests a signal processing approach based on Fourier analysis to mitigate artifacts (Compl. ¶21). The complaint does not provide sufficient detail for a technical analysis of how the FAST-SpO2 technology operates internally. No probative visual evidence provided in complaint.

IV. Analysis of Infringement Allegations

The complaint does not provide sufficient detail for a claim-by-claim or element-by-element analysis of infringement. It makes general allegations that the accused products, by incorporating FAST-SpO2 technology, infringe "at least one claim" of each asserted patent (e.g., Compl. ¶24, ¶30). The core of the infringement allegation is that the FAST-SpO2 technology performs the patented signal processing methods.

Identified Points of Contention

  • Scope Questions: A central question for the '272 Patent will be whether Philips' FAST-SpO2 technology performs the claimed step of "determining a value of coefficient rₐ which minimizes correlation between s₁ and n₁." The dispute may center on whether a Fourier-based filtering method is equivalent to the specific correlation-minimizing adaptive process described in the patent. Similarly, for the '952 Patent, a key question is whether FAST-SpO2 technology can be properly characterized as the claimed "waveform scrubber" using a "scrubber coefficient."
  • Technical Questions: What evidence does the complaint provide that the accused FAST-SpO2 technology implements the specific signal models and processing steps recited in the asserted claims? The complaint's reliance on the marketing name "Fourier Artifact Suppression Technology" raises the question of whether this technology's actual operation matches the functional requirements of the claims, which are rooted in an adaptive correlation cancellation framework.

V. Key Claim Terms for Construction

U.S. Patent No. 5,632,272

  • The Term: "a value of coefficient rₐ is determined which minimizes correlation between s₁ and n₁" (from Claim 1).
  • Context and Importance: This phrase describes the core inventive step. The definition of "minimizes correlation" will be critical. Practitioners may focus on this term because the infringement dispute will likely turn on whether the accused FAST-SpO2 technology, which on its face suggests a frequency-domain filtering approach, performs a function that can be defined as "minimizing correlation" between modeled signal components.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The specification describes the goal more generally as removing signal components from one input that are correlated to a second input, which could support an interpretation not limited to a single algorithm (’272 Patent, col. 3:34–41).
    • Evidence for a Narrower Interpretation: The patent details specific embodiments using a correlation canceler and an extremum detector that identifies a minimum in power output, which corresponds to minimum correlation. This could support an argument that the claim is limited to such adaptive, power-minimizing processes (’272 Patent, FIG. 7a; col. 20:11–26).

U.S. Patent No. 6,002,952

  • The Term: "waveform scrubber" (from Claim 1).
  • Context and Importance: Infringement hinges on whether the FAST-SpO2 system is a "waveform scrubber." Practitioners may focus on this term because its construction will determine if a system named for its use of Fourier analysis falls within the scope of a claim that uses the term "scrubber."
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The abstract describes the invention broadly as a method to "analyze two measured signals" and "remove the unwanted portions," which could be argued to encompass any technology that cleans a signal based on information from another (’952 Patent, Abstract).
    • Evidence for a Narrower Interpretation: The detailed description links the "waveform scrubber" to a specific signal processing block that operates using a "scrubber coefficient" (α) derived from analyzing ratios in the frequency domain, potentially limiting the term to that specific architecture (’952 Patent, FIG. 12; col. 4:57–63).

VI. Other Allegations

  • Indirect Infringement: The complaint makes general allegations of direct and indirect infringement under 35 U.S.C. § 271(a), (b), or (c) for each asserted patent (e.g., Compl. ¶24, ¶30). The complaint does not, however, allege specific facts to support the knowledge and intent elements required for induced or contributory infringement, such as references to product manuals or marketing materials that instruct on infringing use.
  • Willful Infringement: For each patent, the complaint alleges that Masimo notified Philips of the patent's existence and that Philips' infringement has been and continues to be willful, deliberate, and intentional (e.g., Compl. ¶25-26, ¶31-32). This frames the willfulness allegation as arising from knowledge obtained at or after receiving notice from the patentee.

VII. Analyst’s Conclusion: Key Questions for the Case

This dispute will likely center on two key questions for the court:

  • Technical Equivalence: A core evidentiary question will be one of technical and functional equivalence: does Philips' "Fourier Artifact Suppression Technology" operate in a manner that is structurally or functionally equivalent to the adaptive correlation-canceling and signal-modeling methods described and claimed in Masimo's patents, or is it a distinct technological approach to noise reduction?
  • Definitional Scope: The case will also turn on a question of definitional scope: can claim terms rooted in the language of adaptive signal processing, such as "minimizes correlation" and "waveform scrubber," be construed broadly enough to encompass a system that is described and potentially operates using principles of Fourier analysis and frequency-domain filtering?