DCT
5:25-cv-01534
Earin Ab v. Audio Technica US Inc
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Earin AB (Sweden)
- Defendant: Audio-Technica U.S., Inc. (Delaware)
- Plaintiff’s Counsel: The Webb Law Firm
- Case Identification: 5:25-cv-01534, N.D. Ohio, 07/23/2025
- Venue Allegations: Venue is alleged to be proper in the Northern District of Ohio because the defendant is a resident of the district, with its principal place of business located in Stow, Ohio.
- Core Dispute: Plaintiff alleges that Defendant’s true wireless stereo (TWS) earbuds infringe a patent related to automatic power management and connection logic that governs how the earbuds operate when removed from or placed into their charging case.
- Technical Context: The technology addresses automated power-saving and connection-handling features for TWS earbuds, a highly competitive and ubiquitous category in consumer electronics.
- Key Procedural History: The complaint notes that Plaintiff launched its own TWS earbuds, the Earin M-1, on October 6, 2015, establishing its presence in the market. No other significant procedural events are mentioned.
Case Timeline
| Date | Event |
|---|---|
| 2014-09-05 | Priority Date for U.S. Patent No. 9,402,120 |
| 2015-10-06 | Plaintiff Earin launches its M-1 TWS earbuds |
| 2016-07-26 | U.S. Patent No. 9,402,120 issues |
| 2025-07-23 | Complaint filed |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 9,402,120 - Wireless Earbuds
Issued July 26, 2016
The Invention Explained
- Problem Addressed: The patent background identifies characteristics important to the growing market for wireless earbuds, including "convenience and user-friendliness, duration between battery chargings, [and] operational reliability" ('120 Patent, col. 1:19-22). The invention aims to offer improvements in this technical field ('120 Patent, col. 1:26-28).
- The Patented Solution: The patent describes a method for "automatic power preservation" where an earbud autonomously manages its power state and wireless connections ('120 Patent, col. 1:45-47). When connected to a charger, the earbud enters an "idle mode" and disconnects existing wireless links. When removed from the charger, it enters an "operational mode," automatically attempting to establish a TWS connection with a second earbud. The system includes a logical hierarchy for handling connection successes or failures, such as falling back to a "mono" mode or attempting to reconnect to a known host device ('120 Patent, col. 1:53-col. 2:4; Fig. 12).
- Technical Importance: This automated logic seeks to enhance user experience by eliminating the need for manual power cycling and connection management, a key factor for usability and battery conservation in small, portable devices ('120 Patent, col. 9:38-44).
Key Claims at a Glance
- The complaint asserts infringement of at least independent claim 20 (Compl. ¶19).
- Essential elements of independent claim 20 include:
- A wireless earbud comprising a housing, loudspeaker, rechargeable battery, and a main printed circuit board with control circuitry.
- The circuitry is configured for automatic power preservation.
- This is achieved by detecting connection to a charger and, in response, entering an "idle mode" where wireless connections are disconnected.
- Upon detecting disconnection from the charger, the earbud enters an "operational mode."
- The operational mode involves a sequence of steps: attempting TWS reconnection; operating in TWS or mono mode based on success; if in TWS mode, determining its role as master or slave; if master, attempting to reconnect to a host device; and if reconnection fails, initiating a pairing procedure.
III. The Accused Instrumentality
Product Identification
- The complaint identifies the Audio-Technica ATH-TWX9, ATH-TWX7, ATH-CKS50TW, and ATH-CKS30TW+ Wireless Earbuds as the "Accused Products," with the ATH-TWX9 model used as a representative example for the infringement analysis (Compl. ¶2, ¶22).
Functionality and Market Context
- The complaint alleges that the Accused Products contain the necessary hardware components, including a housing, loudspeaker, rechargeable battery, and a main printed circuit board with wireless communication circuitry (Compl. ¶24-29). The core accused functionality is the automatic behavior of the earbuds when managed by their charging case. The complaint alleges that when placed in the case, the earbuds enter an "idle mode" by turning off and disconnecting, and when removed, they enter an "operational mode" by automatically powering on and attempting to form a TWS connection (Compl. ¶31, ¶33). A teardown photo of the ATH-TWX9 is provided to show its internal printed circuit board (Compl. ¶28, p. 8). The complaint supports its allegations with references to product documentation, marketing materials, and what it describes as "product testing," including screenshots from Bluetooth packet logging software (Compl. ¶23, ¶33, ¶¶37-44).
IV. Analysis of Infringement Allegations
'120 Patent Infringement Allegations
| Claim Element (from Independent Claim 20) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| [Preamble] A wireless earbud having an idle mode and an operational mode... | The ATH-TWX9 earbuds allegedly enter an "idle mode" when placed in the charging case and an "operational mode" when removed. | ¶23 | col. 9:46-48 |
| [20.d] at least one main printed circuit board having disposed thereon circuitry for wireless radio communication, audio codec and earbud operation control; | The ATH-TWX9 is alleged to have a main PCB with circuitry for Bluetooth 5.2, audio codecs like Qualcomm aptX, and operation control via touch sensors and buttons. The complaint includes a photograph of the alleged PCB. | ¶27-29 | col. 10:54-58 |
| [20.e.1] detecting connection of said battery to a charger and in response entering the idle mode, wherein existing connections...will be disconnected; | The earbuds allegedly turn off and disconnect from host devices when placed in the charging case. The complaint presents a packet logger screenshot allegedly showing a "Disconnection Complete" event. | ¶30-31, ¶40 | col. 10:59-65 |
| [20.e.2] detecting disconnection of said battery from said charger and in response entering the operational mode by: | The earbuds allegedly turn on automatically when removed from the charging case, which is evidenced by product literature showing the "Power supply ON/OFF" function. | ¶32-33 | col. 10:66-col. 11:2 |
| [20.e.2.i] attempting a true wireless stereo, TWS, reconnection with the second wireless earbud; | Based on product testing, the complaint alleges that upon removal from the case, the earbuds automatically attempt to form a TWS connection. | ¶33 | col. 11:3-5 |
| [20.e.2.ii] if the attempt is successful, operating the wireless earbud as a TWS audio receiver and otherwise operating the wireless earbud as a mono wireless audio receiver; | Based on product testing, the complaint alleges that the earbuds operate in TWS mode if the connection is successful and in mono mode if it fails (e.g., if only one earbud is removed). | ¶34 | col. 11:6-9 |
| [20.e.2.iii] if operated as a TWS audio receiver, determining whether the wireless earbud is a master device or a slave device... | The complaint alleges this determination is made in accordance with Bluetooth Core Specification Version 5.2, which defines master and slave roles. | ¶35 | col. 11:10-13 |
| [20.e.2.iv] if the wireless earbud is determined to be a master device, attempting to reconnect with the wireless audio streaming host device... | The complaint alleges the earbuds attempt to reconnect to previously paired host devices, providing packet logger screenshots showing a "Connection Request" to two different devices. | ¶36-39, ¶41, ¶43 | col. 11:14-18 |
| [20.e.2.v] if reconnection with the wireless audio streaming host device fails, initiate a pairing procedure... | If reconnection fails, the earbuds are alleged to initiate a pairing procedure by advertising their availability, supported by a packet logger screenshot showing an "Inquiry Result – EIR" event. | ¶42, ¶44-45 | col. 11:19-23 |
- Identified Points of Contention:
- Scope Questions: A question may arise as to whether the specific Bluetooth events shown in the complaint's packet logger evidence (e.g., a "Connection Request" or an "Inquiry Result – EIR" broadcast) satisfy the specific functional language of the claim, such as "attempting to reconnect" or "initiate a pairing procedure" as those terms are understood in the context of the patent specification.
- Technical Questions: The complaint alleges several claim limitations are met based on "information and belief" and "product testing" (e.g., the fallback to mono mode and the master/slave determination). A key question will be whether discovery produces technical evidence, such as source code or detailed testing data, that corroborates these specific operational steps and demonstrates that the accused products perform the entire claimed logical sequence in the prescribed order.
V. Key Claim Terms for Construction
The Term: "initiate a pairing procedure"
Context and Importance: This term describes the final step in the claimed logic sequence (20.e.2.v) when an earbud fails to reconnect to a known host device. The complaint's infringement allegation for this step hinges on interpreting a Bluetooth "Inquiry Result" event as satisfying this limitation (Compl. ¶45). The construction of this term is therefore critical to determining if the accused product performs this claimed function.
Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The patent uses the term generally. The flowchart in Figure 12 shows a path leading to a state labeled "Go into mobile paring [sic] mode" (Fig. 12, box 160). A party could argue that any action that makes the earbud discoverable for pairing, such as broadcasting an inquiry response, falls within the plain meaning of "initiating" such a procedure.
- Evidence for a Narrower Interpretation: The claim states "initiate a pairing procedure with the wireless audio streaming host device..." ('120 Patent, col. 11:21-22). A party could argue this requires more than a general, untargeted broadcast and implies a more specific, interactive sequence directed at a particular device or class of devices, potentially rendering the complaint's evidence of a general "Inquiry Result" insufficient.
The Term: "idle mode"
Context and Importance: The transition into and out of "idle mode" and "operational mode" gates the entire automatic power preservation sequence of Claim 20. Defining what constitutes "idle mode" is fundamental to the infringement analysis.
Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The specification describes the idle mode functionally as a state where "existing connections...will be disconnected" in response to connecting to a charger ('120 Patent, col. 9:3-7). This could be interpreted broadly to encompass any powered-down or low-power charging state where wireless radios are inactive.
- Evidence for a Narrower Interpretation: Claim 20 explicitly links entering the idle mode to the act of "detecting connection of said battery to a charger" ('120 Patent, col. 10:59-61). A party could argue that this requires a specific triggering event and state change, and not merely being physically placed in a case. The flowchart in Figure 12, beginning from "Charger disconnected" (Fig. 12, box 122), could be used to argue for a specific, structured process rather than a general state.
VI. Other Allegations
The complaint does not allege willful or indirect infringement.
VII. Analyst’s Conclusion: Key Questions for the Case
This case appears to center on whether the automated functions of a modern TWS earbud map onto the specific logical sequence claimed in the '120 patent. The key questions for the court will likely be:
A core issue will be one of claim construction: can the functional steps recited in Claim 20, such as "initiate a pairing procedure," be construed broadly enough to read on the general Bluetooth events (e.g., "Inquiry Result") shown in the complaint's evidence, or does the patent's context require a more specific technical implementation?
A key evidentiary question will be one of operational proof: beyond the provided packet logs, what technical evidence will emerge from discovery to demonstrate that the accused earbuds' firmware executes the entire multi-step decision-making process of Claim 20 in the specified order, particularly for steps alleged on "information and belief" like the mono-mode fallback and the master/slave determination?