DCT
1:16-cv-00683
Blackbird Tech LLC v. Fitbit Inc
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Blackbird Tech LLC d/b/a Blackbird Technologies (Delaware)
- Defendant: Fitbit, Inc. (Delaware)
- Plaintiff’s Counsel: Stamoulis & Weinblatt LLC
- Case Identification: 1:16-cv-00683, D. Del., 08/08/2016
- Venue Allegations: Venue is alleged to be proper in the District of Delaware because Defendant is a Delaware corporation that transacts business and sells the accused products within the district.
- Core Dispute: Plaintiff alleges that Defendant’s line of wearable fitness trackers infringes a patent related to methods for more accurately calculating distance traveled by a user.
- Technical Context: The technology at issue falls within the wearable health and fitness monitoring market, where devices track physical activity metrics like steps taken and distance traveled.
- Key Procedural History: The patent-in-suit was the subject of multiple Inter Partes Review (IPR) proceedings filed after the date of this complaint. An IPR certificate issued on May 26, 2020 indicates that claims 1-6 of the patent, which includes all claims asserted in this complaint, have been cancelled. Claims 7-8 were found patentable. This post-complaint development raises a significant question regarding the viability of the asserted claims.
Case Timeline
| Date | Event |
|---|---|
| 1998-10-28 | '212 Patent Priority Date |
| 2002-08-13 | '212 Patent Issue Date |
| 2016-08-08 | Complaint Filing Date |
II. Technology and Patent(s)-in-Suit Analysis
- Patent Identification: U.S. Patent No. 6,434,212, "Pedometer," issued August 13, 2002.
The Invention Explained
- Problem Addressed: The patent describes that prior art pedometers were often inaccurate (Compl. ¶13). Some used wrist-mounted step counters that could misinterpret any arm movement as a step, while others used a fixed stride length that failed to account for the fact that a user's stride length changes with their speed (i.e., stride rate) ('212 Patent, col. 4:47-55).
- The Patented Solution: The invention claims to improve accuracy by using an algorithm that dynamically calculates a user's stride length based on their current stride rate. The system first establishes a "Base Stride Rate" and "Base Stride Length" during a calibration run over a known distance ('212 Patent, col. 5:56-65). During subsequent use, the device continuously measures the "Actual Stride Rate" and applies a formula to derive a corresponding "Actual Stride Length," which is then used to calculate the distance traveled ('212 Patent, col. 5:30-47). This allows the distance calculation to adapt to changes in the user's pace during a workout.
- Technical Importance: This approach sought to provide more accurate, real-time distance tracking for runners and walkers by moving beyond static, one-size-fits-all calculations and accounting for the dynamic relationship between pace and stride length (Compl. ¶15).
Key Claims at a Glance
- The complaint asserts independent claims 2, 5, and 6.
- Independent Claim 2: An exercise monitoring device comprising:
- a strap for securing the device to a user;
- a step counter joined to the strap;
- a heart rate monitor joined to the strap; and
- a data processor programmed to calculate distance using a stride length that varies with stride rate, where the stride length is determined with reference to a plurality of calibrations.
- Independent Claim 5: An exercise monitoring device comprising:
- a strap for securing the device to a user;
- a step counter joined to the strap;
- a heart rate monitor joined to the strap; and
- a data processor programmed to calculate distance using a variable stride length, and further programmed to derive that stride length from a range of stride lengths calculated from a range of stride rates based on a plurality of calibration samples.
- Independent Claim 6: A pedometer comprising:
- a step counter;
- a transmitter to generate and transmit a step count signal;
- a receiver mountable on a user's body to receive the signal; and
- a data processor programmed to calculate distance using a variable stride length, and further programmed to derive an actual stride length from a range of stride lengths calculated from a range of corresponding stride rates.
III. The Accused Instrumentality
Product Identification
- The complaint accuses the Fitbit Charge HR, Charge, Surge, Blaze, Alta, and Flex products (Compl. ¶9).
Functionality and Market Context
- The accused products are wearable electronic devices that monitor a user's physical activity. The complaint alleges these devices contain a data processor and utilize a "finely tuned algorithm" for step counting that accounts for both walking and running (Compl. ¶¶20-21). Specifically, the complaint alleges the devices "calculate distance by multiplying [] walking steps and walking stride length ... [and] running steps are multiplied by [] running stride length" (Compl. ¶23). The complaint further alleges that users can "adjust" the device's algorithm by inputting their personal stride length for both walking and running after measuring it over a known distance, which the complaint frames as a calibration feature (Compl. ¶¶25-26).
- No probative visual evidence provided in complaint.
IV. Analysis of Infringement Allegations
The following chart summarizes the infringement allegations for Claim 6, which is asserted against all accused products.
'212 Patent Infringement Allegations
| Claim Element (from Independent Claim 6) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| a step counter | The accused products are described as pedometers that include a step counter. | ¶¶ 33, 76, 88 | col. 6:64 |
| a transmitter in communication with the step counter to generate a step count signal corresponding to each step and transmit the step count signal | The complaint infers the presence of a transmitter from the fact that the accused products can display "steps." | ¶¶ 29, 34, 72, 77, 89 | col. 8:8-12 |
| a receiver mountable on a user body portion to receive the step count signal transmitted from the transmitter | The complaint alleges the receiver is part of the wrist-worn device and is thus mountable on a user body portion. | ¶¶ 30, 35, 73, 78, 90 | col. 8:12-14 |
| a data processor programmed to calculate a distance traveled by multiplying a number of steps counted by a stride length that varies according to a rate at which steps are taken, and further programmed to derive an actual stride length from a range of stride lengths calculated from a range of corresponding stride rates | The accused products allegedly calculate distance by multiplying steps by separate stride lengths for walking and running, which the complaint contends satisfies this limitation. The ability for a user to input their personal stride lengths is alleged to be a form of calibration. | ¶¶ 22-28, 38-42 | col. 8:15-22 |
- Identified Points of Contention:
- Scope Questions: The complaint's theory for the "transmitter" and "receiver" elements appears to be based on inference rather than direct evidence. It raises the question of whether the self-contained architecture of the accused products includes the distinct transmitter/receiver components required by claim 6, or if the claim language can be construed to cover internal data pathways within a single integrated device.
- Technical Questions: A central question is whether the accused products' alleged method—using two distinct stride lengths (one for walking, one for running)—meets the claim requirement to "derive an actual stride length from a range of stride lengths calculated from a range of corresponding stride rates." The court may need to determine if two data points constitute a "range" in the context of the patent, which describes a more continuous, formula-based derivation ('212 Patent, col. 5:47-55).
V. Key Claim Terms for Construction
The Term: "derive an actual stride length from a range of stride lengths calculated from a range of corresponding stride rates" (Claim 6)
- Context and Importance: This term is the central technical limitation that distinguishes the invention from prior art using fixed stride lengths. The outcome of the infringement analysis may depend heavily on whether the accused products' use of two discrete stride values (walking and running) is found to fall within the scope of this "derivation from a range" language.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: A party could argue that having two distinct calibrations (one for walking, one for running) creates a "range" of stride rates and a corresponding "range" of stride lengths, and that switching between them constitutes a "derivation."
- Evidence for a Narrower Interpretation: The patent specification describes a more complex method, including an algorithm with a variable "N" and sample runs at three different paces (slow, normal, fast) to create a customized calculation ('212 Patent, col. 5:62-65, col. 6:1-10). This may support an interpretation that requires a more granular, multi-point calibration and a functional relationship for deriving stride length, not just switching between two preset values.
The Term: "transmitter" and "receiver" (Claim 6)
- Context and Importance: Practitioners may focus on these terms because the complaint infers their existence in the self-contained accused products. The patent's specification and figures depict these as potentially separate components communicating wirelessly ('212 Patent, Fig. 1; col. 5:13-22), creating a potential mismatch with the integrated hardware of the accused devices.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: A party could argue that these terms should be interpreted functionally to mean any components that send and receive step data, even if they are simply different parts of the same integrated circuit within a single housing.
- Evidence for a Narrower Interpretation: The specification discusses transmitting signals "from a user's waist to wrist" and mentions "Rf telemetric signal transmitter" technology ('212 Patent, col. 5:13-16). This language may support an argument that the claims require physically or logically distinct components capable of communication over a distance, not merely internal data transfer.
VI. Other Allegations
The complaint does not contain separate counts or specific factual allegations to support claims for indirect infringement or willful infringement.
VII. Analyst’s Conclusion: Key Questions for the Case
Procedural Viability: The most significant issue is procedural. Given that an IPR proceeding concluded after the complaint was filed resulted in the cancellation of all asserted claims (2, 5, and 6), the primary question is whether the Plaintiff's case can proceed on claims that are no longer valid.
Claim Scope: A core technical issue will be one of definitional scope: does the accused functionality of switching between a pre-set "walking stride length" and a "running stride length" meet the claim requirement to "derive an actual stride length from a range of stride lengths calculated from a range of corresponding stride rates"?
Evidentiary Sufficiency: A key evidentiary question will be one of component architecture: does the complaint adequately allege that the integrated, wrist-worn accused products contain the separate "transmitter" and "receiver" components recited in claim 6, or is there a fundamental mismatch between the claimed architecture and the accused products?