US 9402120B2

As of April 26, 2026, here is a concise summary of US Patent 9,402,120 B2.

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Patent Summary: US 9,402,120 B2

Title: Wireless earbuds

Assignee: The patent lists Earin AB as the current assignee. The original assignee was Epickal AB.

Inventors: Olle Lindén, Kiril TRAJKOVSKI, Per Sennström, Carl Ståhl, Markus Millfjord, Henrik Hovmøller.

Filing Date: September 5, 2014

Issue Date: July 26, 2016

Abstract:
A wireless earbud has an earbud housing having a longitudinal main axis and an essentially circular cross section, a loudspeaker element, a rechargeable battery, at least one main printed circuit board having disposed thereon circuitry for wireless radio communication, audio codec and earbud operation control, and a charging interface member. The loudspeaker element, the rechargeable battery, the main printed circuit board and the charging interface member are arranged in a successive order along the longitudinal main axis of the earbud housing.

Plain-Language Overview of Independent Claims

This patent has four independent claims, which represent the core inventions protected.

Independent Claim 1: This claim describes the fundamental physical structure of a wireless earbud. It requires the earbud to have a cylindrical or cone-like shape where the key internal components—the speaker, rechargeable battery, main circuit board, and charging interface—are arranged in a straight line, one after another, along the length of the earbud. Specifically, it dictates that the circuit board is at the rear of the earbud, followed by the battery, and then the speaker, all packed sequentially inside the housing.

Independent Claim 12: This claim focuses on the design of the antenna within the earbud. It describes an earbud with the same linear arrangement of components as in claim 1, but the key innovation is that the antenna for wireless communication is an elongated radiator pattern located on the circumferential edge of the main circuit board. This placement is intended to maximize antenna performance within the compact, cylindrical form factor.

Independent Claim 20: This claim details a method for automatic power management and connectivity. It describes a wireless earbud that, without manual input:

• Enters an "idle mode" when connected to a charger, disconnecting from any paired earbud or audio source.
• Enters an "operational mode" upon being disconnected from the charger, where it automatically tries to reconnect with a second earbud for True Wireless Stereo (TWS).
• If it successfully connects as a TWS pair and determines it is the "master" device, it then attempts to reconnect to a known audio streaming device (like a smartphone).

Independent Claim 22: This claim describes a power-saving feature for a host device (e.g., a smartphone) connected to a pair of wireless earbuds. The host device's controller is designed to:

• Receive the current battery level from both the left and right earbuds.
• Determine which earbud is acting as the "master" (which consumes more power) and which is the "slave."
• Based on the battery levels, the host device can command the earbuds to swap roles—making the master the slave and vice versa—to more evenly distribute power drain and extend the total listening time.

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Disclaimer: My access to the CAFC (Court of Appeals for the Federal Circuit) dockets is not real-time. As of today's date, I have no information regarding any litigation involving US Patent 9,402,120 B2 in the 2026 dockets.