Wristdocs LLC v. Zepp Health Corp

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Wristdocs LLC (Tennessee)
  • Defendant: Zepp Health Corporation (China)
  • Plaintiff’s Counsel: Ramey LLP
• Case Identification: 6:23-cv-00536, W.D. Tex., 07/24/2023
• Venue Allegations: Plaintiff alleges that venue is proper because Defendant is a foreign corporation, and under 28 U.S.C. § 1391(c)(3), such a corporation may be sued in any judicial district where it is subject to personal jurisdiction. The complaint asserts personal jurisdiction based on Defendant’s alleged continuous and systematic business in the district, including sales of the accused products to residents.
• Core Dispute: Plaintiff alleges that Defendant’s Amazfit Band 7 wearable fitness tracker infringes a patent related to a wrist-worn biotelemetry system.
• Technical Context: The lawsuit concerns the field of wearable health monitoring devices, specifically pulse oximeters integrated into a wristband form factor for continuous or on-demand biological data collection.
• Key Procedural History: The complaint does not mention any prior litigation, licensing history, or post-grant proceedings involving the patent-in-suit.

Case Timeline

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

U.S. Patent No. 9,392,970 - "Biotelemetry system"

• Patent Identification: U.S. Patent No. 9,392,970, "Biotelemetry system", issued July 19, 2016.

The Invention Explained

• Problem Addressed: The patent describes a problem with prior art pulse oximeters, which are noted to "suffer from lack of a secure fit" as they are primarily attached via a clip to a fingertip ('970 Patent, col. 2:50-52). Even wrist-worn display modules at the time still required a sensor tethered to the fingertip ('970 Patent, col. 2:55-59).
• The Patented Solution: The invention proposes a biotelemetry system where the sensor module is integrated directly into a banding mechanism worn on the wrist, eliminating the need for a tethered finger-clip sensor and thereby improving "function and utility" ('970 Patent, col. 2:59-62). The system is described as portable, disposable, and optionally modular, designed for use on various extremities ('970 Patent, col. 2:15-18). A key structural feature is a "strut enveloped lengthwise" within the band, which provides a "bending pressure" that causes the device to coil and ligature around the wrist ('970 Patent, col. 8:60-65).
• Technical Importance: The claimed solution aims to make biotelemetry more practical for long-term, stable, or emergency monitoring by moving the sensor to the wrist, which allows for a more secure and less obtrusive fit compared to fingertip-based devices ('970 Patent, col. 2:50-62, col. 3:9-15).

Key Claims at a Glance

• The complaint asserts at least independent claim 1 ('970 Patent, col. 8:25-col. 9:8; Compl. ¶18).
• Essential elements of independent claim 1 include:
  • "two or more disposable pulse oximeter sensor modules"
  • A "banding mechanism" configured to be worn around the wrist and maintain contact with at least 50% of the wrist skin surface
  • An "integral pocket" in the banding mechanism to receive the sensor modules
  • A "strut enveloped lengthwise within said banding mechanism," configured so that providing "bending pressure" results in "the coiling of the strut and ligature of the banding mechanism around the wrist"
  • A "window area on the skin contacting surface" of the banding mechanism to allow light to pass through
  • A "signal processing unit" that determines the percentage of hemoglobin bound with oxygen
• The complaint reserves the right to assert other claims ('Compl. ¶18).

III. The Accused Instrumentality

Product Identification

• The complaint identifies "Zepp's Amazfit Band 7" as an exemplary accused product (Compl. ¶16).

Functionality and Market Context

• The complaint does not provide a technical description of the Amazfit Band 7's functionality. It identifies the product via a URL to a product page (Compl. ¶16). It is alleged that the product is sold and marketed to residents of the Western District of Texas (Compl. ¶8, fn. 1). The complaint asserts that the Accused Products are available to individuals and businesses throughout the United States (Compl. ¶22).

IV. Analysis of Infringement Allegations

The complaint alleges that Defendant directly infringes at least claim 1 of the ’970 Patent by making, using, selling, and importing the Accused Products (Compl. ¶18). The complaint states that a claim chart describing the infringement is attached as Exhibit B (Compl. ¶24). However, Exhibit B was not included with the publicly filed complaint. Therefore, the complaint itself does not contain specific factual allegations mapping elements of the accused device to the limitations of claim 1. No probative visual evidence provided in complaint.

• Identified Points of Contention: Lacking a detailed infringement theory in the complaint, analysis must focus on potential areas of dispute based on the claim language itself.
  • Technical Question: A primary question will be whether the Amazfit Band 7 contains the specific structure of a "strut enveloped lengthwise" within its band that causes "coiling" upon the application of "bending pressure," as recited in claim 1. This appears to describe a specific mechanical action, potentially akin to a "slap bracelet," which may or may not be present in a conventional watch-style band.
  • Scope Question: The claim requires "two or more disposable pulse oximeter sensor modules." A key issue may be whether the accused product's sensor suite, which may be a single integrated component, meets this limitation. The interpretation of "module" and whether components within a single physical housing can be considered separate "modules" could be a central point of dispute.
  • Scope Question: Another question may arise over the term "disposable." The court will need to determine if the accused product, a consumer electronic device, can be considered "disposable" in the manner contemplated by the patent.

V. Key Claim Terms for Construction

• The Term: "a strut enveloped lengthwise within said banding mechanism"

• Context and Importance: This term is a central structural limitation defining how the device attaches to the wrist. The patent specifies that applying "bending pressure" to this strut causes the device to "coil" and "ligature" around the wrist ('970 Patent, col. 8:60-65). The infringement analysis will depend heavily on whether the accused product's band contains a component that functions in this specific mechanical way. Practitioners may focus on this term because it appears to distinguish the invention from conventional buckle or clasp-based wristbands.

• Intrinsic Evidence for Interpretation:

  • Evidence for a Broader Interpretation: The claims do not specify the material or precise mechanism of the strut, which could allow for arguments that any internal stiffening element that helps shape the band meets the limitation.
  • Evidence for a Narrower Interpretation: The specification's description of "coiling" and "ligature" upon applying "bending pressure" suggests a specific "slap-on" type of bistable spring mechanism. The figures, while schematic, do not depict a traditional buckle or clasp ('970 Patent, Figs. 3B, 4A, 4B). A defendant would likely argue the term is limited to this specific embodiment.

• The Term: "two or more disposable pulse oximeter sensor modules"

• Context and Importance: This limitation defines the number and nature of the sensors. The infringement case hinges on whether the accused product contains at least two distinct sensor "modules" and whether they are "disposable." This term is critical as many modern wearables integrate multiple sensing functions into a single, non-disposable hardware package.

• Intrinsic Evidence for Interpretation:

  • Evidence for a Broader Interpretation: Plaintiff might argue that a single physical package containing distinct light emitters and photodetectors constitutes multiple "modules" in a functional sense. The specification also describes the system as "modular" where sensors can be inserted into the banding mechanism ('970 Patent, col. 5:28-32), which could support a broader view of what constitutes a "module."
  • Evidence for a Narrower Interpretation: The plain language "two or more... modules" suggests physically separate units. The patent explicitly contemplates multiple sensors positioned along the band ('970 Patent, Fig. 5; col. 6:9-14). A defendant would likely argue this requires physically distinct and separable sensor components, not a single integrated chip. The term "disposable" also suggests a device intended for limited use, which may not describe a consumer electronic product like the Amazfit Band 7.

VI. Other Allegations

• Indirect Infringement: The complaint alleges induced infringement under 35 U.S.C. § 271(b), stating Defendant knowingly aided and abetted infringement by third parties, such as its customers (Compl. ¶19). It also alleges contributory infringement, stating that Defendant supplies a material part of the infringing system that is not a staple article of commerce and is incapable of substantial non-infringing use (Compl. ¶19). No specific evidence, such as user manuals, is cited in support of these allegations.
• Willful Infringement: The complaint does not explicitly use the word "willful" but includes allegations that may form the basis for such a claim. It alleges that Defendant had knowledge of the ’970 patent, made no attempt to design around the claims, and did not have a reasonable basis for believing the claims were invalid (Compl. ¶19-21). These are boilerplate allegations made "on information and belief."

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

1. A central issue will be one of structural correspondence: Does the accused Amazfit Band 7's wristband contain a "strut" that causes the band to "coil" and "ligature" around the wrist through "bending pressure," or does it use a conventional fastening mechanism that falls outside the scope of the claim?

2. A second key question will be one of component definition: Can the accused product's integrated sensor package be considered "two or more disposable pulse oximeter sensor modules" as required by claim 1, or does the claim require physically separate and disposable components that are absent in the accused device?

3. An initial procedural question will be the sufficiency of the complaint: Given the lack of specific factual allegations mapping the accused product to the claim elements in the complaint itself (relying instead on an unprovided exhibit), the case may face an early motion challenging the pleading standard under Iqbal/Twombly.