DCT
2:25-cv-00141
Ear Technology Corp v. Puretone Ltd
Key Events
Amended Complaint
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Ear Technology Corporation (Tennessee)
- Defendant: Puretone Ltd. (United Kingdom)
- Plaintiff’s Counsel: Luedeka Neely, P.C.
- Case Identification: 2:25-cv-00141, E.D. Tenn., 12/02/2025
- Venue Allegations: Plaintiff alleges venue is proper because Defendant is a foreign corporation subject to personal jurisdiction in the district, having placed the accused products into the stream of commerce with the understanding they would be sold in Tennessee.
- Core Dispute: Plaintiff alleges that Defendant’s DefendEar hearing protection devices infringe three U.S. patents related to user-programmable audio processing, mode selection, and simplified control interfaces for hearing assistance devices.
- Technical Context: The technology involves digital hearing assistance devices that allow users to select from pre-programmed audio profiles and adjust settings without external programming equipment, a key feature for both hearing aids and advanced hearing protectors.
- Key Procedural History: The complaint alleges that Plaintiff's representative met with Defendant in 2013 to discuss Plaintiff's products and patented technology, after which Defendant purchased two of Plaintiff's marked products. Plaintiff also alleges providing Defendant with copies of the patents-in-suit and notice of infringement on or about January 28, 2025, prior to filing the complaint. These allegations form the basis for the willfulness claim.
Case Timeline
| Date | Event |
|---|---|
| 2007-04-25 | Earliest Priority Date for ’968, ’634, and ’272 Patents |
| 2012-10-09 | U.S. Patent No. 8,284,968 Issues |
| 2013-01-01 | Plaintiff's representative meets with Puretone representatives (approx.) |
| 2013-06-25 | U.S. Patent No. 8,472,634 Issues |
| 2015-05-12 | U.S. Patent No. 9,031,272 Issues |
| 2025-01-28 | Plaintiff provides Puretone with notice of infringement (approx.) |
| 2025-12-02 | Complaint Filed |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 8,284,968 - "Preprogrammed hearing assistance device with user selection of program," issued October 9, 2012 (’968 Patent)
The Invention Explained
- Problem Addressed: The patent’s background section describes the conventional fitting procedure for a hearing aid as a complex, costly, and iterative process requiring an audiologist or dispenser to program the device using external equipment ('968 Patent, col. 1:24-62).
- The Patented Solution: The invention is a hearing assistance device pre-loaded with multiple audio processing programs. The user can cycle through and select the preferred program by pressing a button directly on the device's housing, without needing to connect to a computer or other programming interface. The device provides audible feedback, such as a series of beeps, to inform the user which program has been selected ('968 Patent, Abstract; col. 2:37-48).
- Technical Importance: This approach aimed to reduce the cost and complexity of hearing aids by empowering the end-user to perform the initial fitting and selection process.
Key Claims at a Glance
- The complaint asserts independent claim 23 (Compl. ¶25).
- Claim 23 requires, in essence:
- A housing configured to be worn on or in the ear.
- Memory within the housing storing multiple audio processing programs.
- A processor within the housing to execute the selected programs.
- A selection device on the housing allowing a user to select one of the programs.
- A digital-to-analog converter.
- An audio output section that provides amplified sound to the user and also generates audible sounds indicating which program is currently selected, allowing the selection to be determined without connecting to an external device.
- The complaint does not explicitly reserve the right to assert dependent claims.
U.S. Patent No. 8,472,634 - "Preprogrammed hearing assistance device with audiometric testing capability," issued June 25, 2013 (’634 Patent)
The Invention Explained
- Problem Addressed: Like the ’968 Patent, this patent addresses the significant cost and complexity associated with professionally fitting and programming a hearing aid, including the audiometric testing required to establish a baseline for programming (’634 Patent, col. 2:4-16).
- The Patented Solution: The patent describes a hearing aid that includes a built-in audiometric testing mode, allowing the device itself to generate test tones. The user can adjust the volume to their hearing threshold and save the profile, which the device then uses to apply an appropriate amplification formula. The asserted claims, however, focus on the user control mechanism for switching between different operational programs and modes (’634 Patent, Abstract; col. 8:8-13).
- Technical Importance: This technology further simplifies the fitting process by integrating self-administered hearing tests, potentially eliminating another step requiring professional intervention.
Key Claims at a Glance
- The complaint asserts independent claims 17 and 20 (Compl. ¶¶33, 40).
- Claim 17 requires, in essence:
- A housing, processor, D/A converter, audio output, and memory storing programs.
- A switching device on the housing that generates a control signal based on a user's action.
- The processor, in response to the signal, ceases execution of one program and commences execution of another.
- Claim 20 requires, in essence:
- A housing, audio output, memory, processor, and D/A converter.
- A switching device that operates in both a "program switching mode" (to switch between different audio programs) and a "volume control mode" (to adjust sound volume).
- The complaint does not explicitly reserve the right to assert dependent claims.
U.S. Patent No. 9,031,272 - "Hearing assistance apparatus having single multipurpose control device and method of operation," issued May 12, 2015 (’272 Patent)
Technology Synopsis
This patent addresses the need for an easy-to-operate hearing assistance device by claiming a method of using a single multipurpose control device. The method distinguishes between different types of user input—such as a short "tap" versus a longer "press and hold"—to control distinct functions, such as adjusting volume versus switching between different amplification algorithms (’272 Patent, Abstract; col. 2:23-56).
Asserted Claims
The complaint asserts independent method claim 7 (Compl. ¶45).
Accused Features
The complaint alleges that the DefendEar devices' use of a single control mechanism infringes this patent, where a "short press up" or "short press down" adjusts volume, and a "long press up" or "long press down" changes between amplification "modes" (Compl. ¶¶47-49).
III. The Accused Instrumentality
Product Identification
The DefendEar DigitalX5 and DefendEar DigitalX3 hearing protection devices (collectively, "DefendEar Devices") (Compl. ¶23).
Functionality and Market Context
The complaint describes the accused products as in-ear devices that provide hearing protection while also featuring "CENS™ digital technology" (Compl. ¶10). This technology includes multiple selectable "modes," which the complaint equates to the claimed "audio processing programs" (Compl. ¶27). The complaint alleges that users select these modes using a control on the device housing, and the device provides "vocal feedback" to advise the user which mode is active (Compl. ¶31). The same control is allegedly used to adjust volume, distinguishing between a "long press" for mode selection and a "short press" for volume adjustment (Compl. ¶¶48-49). A visual from the complaint's Exhibit D, referenced in the complaint, illustrates this dual-mode control functionality for adjusting volume (Compl. ¶43).
IV. Analysis of Infringement Allegations
’968 Patent Infringement Allegations
| Claim Element (from Independent Claim 23) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| a housing configured to be worn in, on or behind an ear of the person; | The DefendEar Devices include a housing configured to be worn on an ear. | ¶26 | col. 2:39-40 |
| memory disposed within the housing, the memory for storing a plurality of audio processing programs...; | The devices have multiple selectable "modes," which are alleged to be audio processing programs stored in memory. | ¶27 | col. 2:41-43 |
| a processor disposed within the housing and connected to the memory, the processor operable to execute one or more selected audio processing programs...; | The devices contain a processor to execute the selected "modes." | ¶27 | col. 2:41-44 |
| a selection device disposed on the housing and connected to the processor, the selection device operable by the person to select one of the audio processing programs...; | The devices have a mode selection mechanism on the housing operable by the user. A diagram shows "LONG PRESS UP" for "Incremental Mode Selection." | ¶28 | col. 2:44-48 |
| ...the audio output section further for generating one or more audible sounds that indicate to the person which one of the audio processing programs is currently selected... | The devices provide "vocal feedback" that "vocally advises you which mode you are using." | ¶31 | col. 8:11-15 |
| whereby the currently selected audio processing program can be determined without having to connect the apparatus to any external device. | The vocal feedback does not depend on connection to an external device like a smartphone. | ¶32 | col. 2:46-48 |
- Identified Points of Contention:
- Scope Questions: A primary question may be whether the accused "vocal feedback" (Compl. ¶31) falls within the scope of the claim term "one or more audible sounds that indicate... which one of the audio processing programs is currently selected." The patent specification describes this function being performed by a series of "beeps" ('968 Patent, col. 8:12-18), raising the question of whether the claim language should be interpreted as limited to such simple tonal indicators.
’634 Patent Infringement Allegations
| Claim Element (from Independent Claim 17) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| a housing configured to be worn on or in an ear of the person; | The DefendEar Devices include a housing configured to be worn on an ear. | ¶35 | col. 2:27-28 |
| a processor disposed in the housing for executing one or more available programs for processing digital audio signals; | The devices have a processor for executing multiple selectable "modes," which are alleged to be programs for processing digital audio signals. | ¶36 | col. 2:29-31 |
| memory disposed in the housing for storing one or more programs..., the memory accessible to the processor; | The selectable "modes" are stored in the device's memory. | ¶36 | col. 2:34-36 |
| a switching device disposed in the housing for generating a first control signal to switch from one available program to another... based upon an action by the person; | The devices have a mode selection switching device on the housing operable by a person to select the mode. | ¶39 | col. 2:37-41 |
| and the processor for ceasing execution of one of the available programs and commencing execution of another... based upon the first control signal. | When a new mode is selected, the previously selected mode ceases. | ¶39 | col. 2:42-45 |
- Identified Points of Contention:
- Technical Questions: For claim 20, which is also asserted (Compl. ¶40), a key dispute will likely focus on the requirement of a single "switching device" that operates in both a "program switching mode" and a "volume control mode." The complaint alleges this is met by using a "long press" for modes and a "short press" for volume (Compl. ¶¶42-43). The analysis may turn on whether this distinction constitutes two different "modes" of the physical switching device itself, or if it represents a software-level interpretation of signals from a single-mode switch. A visual from the complaint illustrates the button's use for mode selection via a long press (Compl. ¶39).
V. Key Claim Terms for Construction
’968 Patent
- The Term: "audible sounds that indicate... which one of the audio processing programs is currently selected" (Claim 23)
- Context and Importance: The infringement reading for this element relies on the accused devices' "vocal feedback" (Compl. ¶31). The construction of "audible sounds" is therefore critical. If the term is construed narrowly to mean only simple tones, it could present a challenge to the infringement allegation.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The plain language of "audible sounds" is facially broad and does not contain any explicit limitation to tones or beeps.
- Evidence for a Narrower Interpretation: The specification consistently describes the indicator using the word "beeps" (e.g., "the device 10 generates two beeps (step 118)," "the device 10 generates three beeps") ('968 Patent, col. 8:12-18). A party could argue this repeated, specific example defines the scope of the more general claim term.
’634 Patent
- The Term: "a switching device... for operating in a program switching mode... [and] a volume control mode" (Claim 20)
- Context and Importance: This term is central to the patent’s purported innovation of a dual-function control. The infringement case depends on mapping the accused product's "short press" and "long press" functionality onto these two claimed "modes." Practitioners may focus on this term because it requires a specific dual-mode technical operation, not just two functions controlled by the same button.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The claim itself defines the "modes" by their function: one for switching programs and one for adjusting volume. A party could argue that any single switch mechanism capable of controllably initiating both distinct functions meets this limitation, regardless of the underlying electronics.
- Evidence for a Narrower Interpretation: The specification of the parent '968 Patent, from which the '634 Patent derives, depicts the program selection button and volume control as separate hardware components ('968 Patent, FIG. 1, items 28, 34). A party could argue that this context suggests the claimed "modes" require a more substantial hardware or firmware distinction than merely the duration of a button press.
VI. Other Allegations
- Indirect Infringement: The complaint alleges both induced and contributory infringement. The inducement allegations are based on Defendant's dissemination of "promotional and marketing materials, supporting materials, instructions, product manuals, and/or technical information" that allegedly encourage and instruct end-users to operate the DefendEar Devices in an infringing manner (Compl. ¶¶56, 64, 71).
- Willful Infringement: The complaint alleges willful infringement based on Defendant’s alleged knowledge of the patents prior to the lawsuit. The basis for this knowledge includes a 2013 meeting to discuss Plaintiff's patented technology, Defendant's subsequent purchase of Plaintiff's products which were marked with the patent numbers, and a January 2025 notice letter explicitly identifying the patents and the infringing products (Compl. ¶¶50-52, 60, 68, 75).
VII. Analyst’s Conclusion: Key Questions for the Case
- A core issue will be one of definitional scope: can the claim term "audible sounds" in the ’968 Patent, which is described in the specification as simple "beeps," be construed to cover the accused products' more sophisticated "vocal feedback"?
- A key technical question will be one of operational equivalence: does the single control on the accused products, which differentiates between a "short press" for volume and a "long press" for program selection, constitute a device operating in two distinct "modes" as required by claim 20 of the ’634 patent, or is this a software-level interpretation of input from a single-mode hardware switch?
- A third question will concern evidence of intent: will the alleged 2013 meeting and product purchase be sufficient for a fact-finder to determine that Defendant had pre-suit knowledge of the patents and acted with the specific intent required to prove indirect and willful infringement, or could these events be framed as routine competitive analysis?