DCT

6:23-cv-00535

Wristdocs LLC v. Masimo Corp

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 6:23-cv-00535, W.D. Tex., 07/24/2023
  • Venue Allegations: Venue is alleged to be proper based on Defendant's business activities in the Western District of Texas, including developing, designing, distributing, marketing, and selling products, and directing infringing activities into the district.
  • Core Dispute: Plaintiff alleges that Defendant’s pulse oximeter sensor infringes a patent related to a sensor designed for placement on the palm of the hand.
  • Technical Context: The technology concerns non-invasive pulse oximetry, a method for measuring blood oxygenation, with a focus on sensor placement to improve accuracy by reducing motion-related signal interference.
  • Key Procedural History: No prior litigation, Inter Partes Review (IPR) proceedings, or licensing history is mentioned in the complaint. The asserted patent is noted as being subject to a terminal disclaimer.

Case Timeline

Date Event
2013-05-20 U.S. Patent No. 11,331,015 Priority Date
2022-05-17 U.S. Patent No. 11,331,015 Issue Date
2023-07-24 Complaint Filing Date

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

U.S. Patent No. 11,331,015 - "Pulse oximeter sensor", issued May 17, 2022

The Invention Explained

  • Problem Addressed: The patent describes issues with conventional pulse oximeters, particularly those attached to a fingertip or wrist. These designs are susceptible to inaccurate readings due to patient motion, such as wrist flexion or finger curling, which disturbs the sensor and alters the signal (’015 Patent, col. 1:56-col. 2:9).
  • The Patented Solution: The invention proposes a pulse oximeter sensor specifically designed for attachment to the "lower half of the palm or the ular edge of the palm" (’015 Patent, Abstract). This location is described as being "relatively free from motions that interfere with the sensor signals" (’015 Patent, col. 2:9-12). The sensor assembly comprises a multi-layered structure with a light source and detector arranged to measure scattered light from the surface of the palm, as illustrated in the placement diagrams of Figures 10-14 (’015 Patent, col. 2:15-23).
  • Technical Importance: The claimed design seeks to improve the reliability of "point of care" biometric monitoring by providing a stable, motion-resistant location for pulse oximetry, which is critical in both chronic and emergency medical settings (’015 Patent, col. 4:51-57).

Key Claims at a Glance

  • The complaint asserts at least independent claim 1 (Compl. ¶18).
  • Independent Claim 1 requires a method of obtaining pulse oximetry readings by attaching a specific sensor assembly to the ulnar edge of a palm. The essential elements of the sensor assembly itself as recited in the claim are:
    • an elongate body comprising a light emitting source and a detector.
    • the detector comprises an interference shield with a copper foil and a Faraday cage window.
    • a skin-contacting film of elastomeric material with an adhesive surface and openings for the light source and detector.
    • an insulating tape covering the top surface of the elongate body.
    • a cover film of elastomeric material that covers the insulating tape and has a transparent window for visualizing placement.
    • an adhesive to affix the cover film to the other layers.
  • The complaint reserves the right to assert additional claims (Compl. ¶18).

III. The Accused Instrumentality

Product Identification

  • The complaint identifies "Masimo’s LNCS-NEO-L-3 Pulse Oximeter" as an exemplary Accused Product (Compl. ¶16).

Functionality and Market Context

  • The complaint does not provide a technical description of the Accused Product's operation or features. It alleges that the product is a pulse oximeter sold and used throughout the United States (Compl. ¶2, ¶4). No probative visual evidence provided in complaint.

IV. Analysis of Infringement Allegations

The complaint alleges that the Accused Products infringe at least claim 1 of the ’015 Patent (Compl. ¶18). It further states that an attached claim chart in "Exhibit B" describes how the elements of claim 1 are infringed (Compl. ¶24). However, Exhibit B was not included with the filed complaint. Therefore, the complaint itself provides no specific mapping of the Accused Product's features to the limitations of claim 1.

  • Identified Points of Contention: Based on the language of claim 1 and the nature of the technology, the infringement analysis may present several technical and legal questions:
    • Structural Questions: A primary question will be whether the Accused Product, a pulse oximeter sensor, contains the highly specific, multi-component assembly required by claim 1. This includes the "interference shield" with a "copper foil" and "Faraday cage window," the distinct "skin-contacting film," "insulating tape," and "cover film" with a "transparent window," all arranged in the claimed configuration. Evidence will be needed to show that the accused sensor is not merely a generic sensor but embodies this specific layered construction.
    • Scope Questions: The method claim requires "attaching" the sensor to the "ulnar edge of a palm." A point of contention may be whether the intended or actual use of the "LNCS-NEO-L-3 Pulse Oximeter," which appears from its model name to be a neonatal sensor, involves placement on the "ulnar edge of a palm" as depicted and described in the patent, or if it is designed for a different anatomical location (e.g., a foot or finger).

V. Key Claim Terms for Construction

  • The Term: "interference shield configured to protect the detector from radiofrequency/electromagnetic interference, the interference shield comprising: a copper foil; and a Faraday cage window"

    • Context and Importance: This term is highly specific and recites a detailed structure that may not be present in all pulse oximeter sensors. The infringement analysis will depend on whether the accused sensor's components meet these structural requirements. Practitioners may focus on this term because it appears to be a key point of novelty and a potentially significant limitation on claim scope.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: A party could argue that any structure performing the function of shielding from RFI/EMI and made of conductive foil meets the "copper foil" limitation, and any opening allowing light to pass while maintaining shielding integrity meets the "Faraday cage window" limitation.
      • Evidence for a Narrower Interpretation: The specification describes a specific embodiment of the shield constructed from "copper foil and a lead-free solder" and shows a detailed "shield blank" for its formation (’015 Patent, col. 10:57-61; Fig. 9). A party could argue this detailed description limits the term to a structure closely matching this embodiment, including the specific "Faraday cage window 515F" shown in Figure 6.

  • The Term: "ulnar edge of a palm"

    • Context and Importance: The patent's stated purpose is to solve motion-artifact problems by moving the sensor to this specific, allegedly more stable, location. The definition of this anatomical area is therefore central to the claimed method.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The Summary of the Invention refers generally to "the lower half of the palm or the ulnar edge of the palm," suggesting some flexibility in placement (’015 Patent, col. 2:15-16).
      • Evidence for a Narrower Interpretation: The detailed description and figures provide very specific placement guidance. Figure 10 shows the sensor on the "palmar side of the ulnar edge of the palm UEP generally parallel to the fifth digit 5D and generally orthogonal to the wrist crease WC" (’015 Patent, col. 4:41-44). Figure 14 shows the sensor body overlying the fifth metacarpal bone (5MC) and parts of the fourth metacarpal (4MC) and hamate (H) bones (’015 Patent, col. 4:63-col. 5:4). This specific anatomical mapping could be used to argue for a narrower construction.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges inducement and contributory infringement, stating on information and belief that Defendant knowingly and intentionally aided and abetted infringement by third parties, such as its customers (Compl. ¶19). The complaint further alleges the supplied technology is a material part of the invention and is not a staple article of commerce (Compl. ¶19).
  • Willful Infringement: The complaint alleges that Defendant made no attempt to design around the claims of the ’015 Patent and did not have a reasonable basis for believing the claims were invalid (Compl. ¶20, ¶21). The prayer for relief requests a finding of an exceptional case under 35 U.S.C. § 285 (Compl. p. 7).

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

  1. A Structural and Evidentiary Question: Does the accused "Masimo LNCS-NEO-L-3 Pulse Oximeter" actually incorporate the specific multi-layered construction mandated by claim 1, including the distinct elastomeric films, insulating tape, and, most critically, the "interference shield" with a "copper foil" and "Faraday cage window"? The case may turn on whether Plaintiff can produce evidence that the accused device is more than a standard sensor and embodies this precise, complex assembly.
  2. A Method-of-Use and Scope Question: Assuming the structural elements are met, does the intended or directed use of the accused neonatal sensor involve its attachment to the "ulnar edge of a palm," as specifically defined and illustrated in the patent? The infringement analysis for the asserted method claim will hinge on the evidence of where and how the accused product is actually used in practice, as instructed by the Defendant.