DCT

2:24-cv-07182

Zepp Inc v. Amazwear Technology Inc

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 2:24-cv-07182, C.D. Cal., 05/01/2025
  • Venue Allegations: Venue is alleged to be proper as Defendant Amazwear resides in the district, the other corporate defendants are non-U.S. residents and may be sued in any district, and a substantial part of the events giving rise to the claims allegedly occurred in the district.
  • Core Dispute: Plaintiffs allege that Defendants’ smart watches infringe two U.S. patents related to the functional and structural aspects of wearable biometric sensors.
  • Technical Context: The technology at issue involves methods for improving the data reliability of smart watches and the physical construction of their optical sensor modules.
  • Key Procedural History: This action was initiated via a Second Amended Complaint. The complaint also references a cease and desist letter sent by Plaintiff Huami to Defendant Amazwear on December 26, 2023, concerning alleged trademark infringement.

Case Timeline

Date Event
2014-04-07 U.S. Patent No. 10,172,529 Priority Date
2016-06-07 U.S. Patent No. 9,729,693 Priority Date
2017-08-08 U.S. Patent No. 9,729,693 Issued
2019-01-08 U.S. Patent No. 10,172,529 Issued
2023-12-26 Plaintiff Huami sends trademark cease and desist letter to Defendant Amazwear
2025-05-01 Second Amended Complaint Filed

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

U.S. Patent No. 9,729,693 - Determining measurement confidence for data collected from sensors of a wearable device, issued August 8, 2017

The Invention Explained

  • Problem Addressed: The patent describes the problem of wearable devices processing "inappropriate data as biometric measurement data," which can "negatively affect the confidence that the feedback provided is accurate" (’693 Patent, col. 1:30-34). For example, a device not being worn by a user might still collect sensor readings (e.g., from ambient light) and misinterpret them as physiological data ('693 Patent, col. 3:45-55).
  • The Patented Solution: The invention is a multi-stage method to determine if a wearable device is actually being worn by a user before trusting its biometric data ('693 Patent, col. 2:39-42). The method involves a sequence of checks: first, measuring a sample voltage with the light emitter off to detect if the device is in a bright environment; second, measuring another voltage with the emitter on to see if it is in a dark environment (like against skin); and finally, if those checks pass, calculating a "signal quality metric" from the sensor (e.g., a pulse oximeter) to confirm the readings resemble typical human biometric patterns ('693 Patent, Fig. 7; col. 12:1-12).
  • Technical Importance: This approach seeks to improve the reliability of health data from wearables by creating an automated "on-wrist" detection system, thereby reducing false-positive measurements that can occur when a device is not in use. ('693 Patent, col. 4:5-10).

Key Claims at a Glance

  • The complaint asserts independent claims 1, 11, and 16 (Compl. ¶¶27, 35, 40).
  • Independent Claim 1 recites the core elements of the method:
    • determining that a first sample voltage of the wearable device is less than a first threshold voltage;
    • in response to the first determination, determining that a second sample voltage of the wearable device is greater than a second threshold voltage;
    • in response to the second determination, calculating a signal quality metric indicative of data measured by the sensor of the wearable device over a test period;
    • in response to the calculation, determining that the signal quality metric is greater than a measurement threshold indicative of a minimum signal quality metric; and
    • in response to the third determination, determining that the wearable device is worn by a user.
  • The complaint reserves the right to assert various dependent claims (Compl. ¶¶28-34, 36-39, 41-44).

U.S. Patent No. 10,172,529 - Systems and methods for detecting physiological information of a user, issued January 8, 2019

The Invention Explained

  • Problem Addressed: The patent identifies challenges in designing optical sensors for wearables, noting that for optimal performance, the sensor must be "firmly positioned against the user's skin" to block ambient light and that the sensor's light source and photodetector "must be optically isolated from one another" to prevent direct light leakage that would corrupt the measurement (’529 Patent, col. 2:6-20).
  • The Patented Solution: The invention is a specific physical apparatus for a wearable sensor designed to solve these problems ('529 Patent, Abstract). It features a housing with a rear face that contacts the user, a sensor (comprising a light source and a detector), and a key structural element: an "optical barrier" positioned between the source and detector. The patent claims this barrier has both a "laterally-extending portion" and a "vertically-extending portion" that together prevent direct light transmission from the source to the detector ('529 Patent, col. 10:23-33). Figures in the patent depict this barrier as having an inverted T-shaped cross-section ('529 Patent, Fig. 7, barrier 58).
  • Technical Importance: This specific physical construction aims to improve the signal-to-noise ratio and accuracy of reflective optical heart rate sensors by both improving skin contact and preventing internal light "crosstalk." ('529 Patent, col. 2:29-38).

Key Claims at a Glance

  • The complaint asserts independent claims 1, 9, and 16 (Compl. ¶¶51, 59, 61).
  • Independent Claim 1 recites the core structural elements of the apparatus:
    • a housing comprising a front face, a rear face, and an interior region...;
    • a sensor for sensing at least one physiological parameter, the sensor comprising at least one light source for illuminating the targeted area, at least one optical detector for receiving reflected light..., and at least one substrate to which the...light source and...optical detector are mounted; and
    • at least one optical barrier between the at least one light source and the at least one optical detector, the...barrier comprising a laterally-extending portion and a vertically-extending portion...for preventing direct light transmission from the at least one light source to the at least one optical detector.
  • The complaint reserves the right to assert various dependent claims (Compl. ¶¶52-58, 60, 62-64).

III. The Accused Instrumentality

Product Identification

The complaint names a range of smart watches under the "AMAZTIM" and "KOSPET" brands, including but not limited to the AMAZTIM M2, AMAZTIM T2, KOSPET TANK M2, and KOSPET TANK T3 ULTRA (Compl. ¶68). These are collectively referred to as the "Infringing Products."

Functionality and Market Context

The complaint alleges these are smart watches sold throughout the United States that incorporate technology infringing the patents-in-suit (Compl. ¶¶1, 68). The complaint provides URLs to product pages on Amazon.com and brand websites (e.g., amaztim.com, kospet.com) where the products are marketed and sold (Compl. ¶¶76, 87). A screenshot from an Amazon search for "amazfit" is provided, showing a sponsored "AMAZTIM" product listing (Compl. p. 23). Another provided screenshot from an Amazon product page shows a customer question asking if the "AMAZTIM" brand name was copied from the "amazfit" trademark, suggesting market overlap and potential consumer confusion (Compl. p. 22).

IV. Analysis of Infringement Allegations

The complaint references non-proffered exhibits (Exhibits C, E, and F) for its detailed infringement analysis (Compl. ¶¶72, 83). As these exhibits were not included with the complaint, a claim chart summary cannot be constructed. The narrative infringement theories are summarized below.

  • ’693 Patent Infringement Allegations: The complaint alleges that Defendants directly infringe the ’693 patent by making, using, selling, or importing the Accused Products (Compl. ¶71). It asserts that these products practice the claimed methods for determining measurement confidence, with the specific rationale for infringement incorporated by reference to an unattached Exhibit C (Compl. ¶72).
  • ’529 Patent Infringement Allegations: The complaint alleges that the Accused Products directly infringe the ’529 patent (Compl. ¶82). The theory of infringement is that the physical construction of the smart watches, particularly their sensor modules, meets the limitations of the patent's claims. This allegation is supported by reference to unattached Exhibits E and F (Compl. ¶83).
  • Identified Points of Contention:
    • Functional Questions (’693 Patent): The core of the dispute for the ’693 patent will likely concern the specific software and logic implemented in the accused smart watches. A central question for the court may be: what evidence demonstrates that the accused devices perform the specific, multi-step sequence of voltage comparisons and "signal quality metric" calculations required by Claim 1, as opposed to a different or more generic method for assessing data validity?
    • Structural Questions (’529 Patent): The dispute over the ’529 patent will likely focus on the physical construction of the sensor modules in the accused devices. This raises the question: do the devices contain a physical structure that meets the definition of an "optical barrier" with both the "laterally-extending portion" and "vertically-extending portion" as recited in Claim 1, or is there a material structural difference?

V. Key Claim Terms for Construction

  • Term from ’693 Patent: "signal quality metric"

    • Context and Importance: This term is the technical centerpiece of the method in Claim 1 of the ’693 patent. Its definition is critical because the infringement analysis depends on whether whatever calculation the accused devices perform qualifies as this specific "metric." Practitioners may focus on this term to determine if a generic "good signal" indicator is sufficient, or if a more complex, specific calculation is required.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The claim itself uses broad language, defining it only as a "metric indicative of data measured by the sensor" ('693 Patent, col. 14:53-55). This phrasing could support an argument that any numerical indicator of signal quality meets the limitation.
      • Evidence for a Narrower Interpretation: The specification consistently discusses this metric in the context of data from a "pulse oximeter" or "photoplethysmography (PPG) sensor" used to measure biometric data ('693 Patent, Abstract; col. 2:49-54). Dependent claim 6 explicitly recites a PPG sensor (Compl. ¶32). This may support a narrower construction where the metric must be derived from and be indicative of physiological patterns, not just general signal clarity.

  • Term from ’529 Patent: "optical barrier"

    • Context and Importance: This structural element is fundamental to Claim 1 of the ’529 patent. The entire infringement case for this patent may rest on whether the accused watches contain a component that satisfies the claim's definition of this term.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The claim describes the barrier's function as "preventing direct light transmission from the at least one light source to the at least one optical detector" ('529 Patent, col. 10:31-33). A party could argue that any structure that achieves this isolation function, regardless of its exact shape, constitutes an "optical barrier."
      • Evidence for a Narrower Interpretation: The claim explicitly requires the barrier to comprise two distinct parts: "a laterally-extending portion and a vertically-extending portion" ('529 Patent, col. 10:28-29). Furthermore, the specification's embodiment shows this as an "inverted T-shaped barrier" (Fig. 7, barrier 58). This suggests that the term requires a specific two-part geometry, not merely any light-blocking material or structure.

VI. Other Allegations

  • Indirect Infringement: For both the ’693 and ’529 patents, the complaint alleges active inducement, stating Defendants knew of the patents and intended for their U.S. customers to infringe by using the products (Compl. ¶¶74, 85). It also alleges contributory infringement, asserting the accused smart watches are a "material part of the invention," are "especially designed to practice" the patents, and are not staple articles of commerce with substantial non-infringing uses (Compl. ¶¶78-79, 89-90).
  • Willful Infringement: The complaint alleges Defendants' infringement is willful. For the ’693 patent, knowledge is alleged from "at least the filing of this Complaint" (Compl. ¶73). For the ’529 patent, knowledge is alleged "since at least February 2025" and, at a minimum, since the filing of the Second Amended Complaint (Compl. ¶84).

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

  1. A question of functional implementation: For the ’693 patent, the case will likely turn on whether discovery reveals that the accused smart watches' software executes the specific, multi-stage logical process for "on-wrist" detection as recited in the claims, or if they employ a technically distinct method for assessing data quality.
  2. A question of structural correspondence: For the ’529 patent, a central issue will be a direct comparison of physical structures. The outcome may depend on whether the accused devices’ sensor modules contain a physical component that can be properly characterized as an "optical barrier" possessing both the "laterally-extending" and "vertically-extending" portions required by the claims.
  3. An evidentiary question of specificity: The complaint makes broad allegations of infringement while incorporating its detailed theories by reference to unattached exhibits. A primary issue for the litigation will be whether Plaintiffs can produce specific evidence through discovery to substantiate the conclusory claim that the accused products meet, element-by-element, the limitations of the asserted patents.