Capacitive Earphone Stem Input for Tap-Free Force Control
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Solution Overview
Problem
Conventional earphones with mechanical input devices are difficult to operate when worn, as users cannot see the input devices, and alternative input mechanisms like tapping can disrupt audio output and conduct sound, leading to unpleasant experiences and potential microphone interference.
Innovation Solution
The implementation of force-activated earphones that determine a non-binary amount of force applied to a force input surface using a change in capacitance between first and second force electrodes, allowing activation without external mechanical input devices and reducing tapping-related issues, by employing a spring member to bias the force electrode and a flexible circuit that moves with applied force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If mechanical input devices (buttons, dials) are incorporated into earphones, then the earphones can be controlled, but the devices become difficult to operate when worn as users cannot see the input devices
Solution Approach 1:
The patent removes traditional mechanical input devices (buttons, dials) from the earphone structure and replaces them with a force-sensitive capacitive sensor system. The force input surface is integrated directly into the earphone housing, allowing users to provide input through tactile force application rather than manipulating visible mechanical components. This extraction of mechanical elements simplifies the overall device structure while improving ease of operation through invisible, intuitive force-based control.
Solution Approach 2:
The patent replaces the mechanical input device system with an electrical sensing system based on capacitive force detection. Instead of using physical buttons or dials that require visual confirmation and manual manipulation, the system uses force electrodes that detect changes in capacitance caused by applied force. This substitution eliminates the need for visible mechanical components while providing continuous, nuanced input capability through force magnitude detection.
2Ease of operation
If tapping mechanisms are used for input, then the earphones can be activated, but audio output is disrupted and sound is conducted, leading to unpleasant experiences and potential microphone interference
Solution Approach 1:
The patent replaces tapping mechanisms with a force-sensitive capacitive sensing system that detects applied force through changes in capacitance between force electrodes. This substitution allows the earphone to distinguish between intentional force input and environmental vibrations, enabling input activation without the audio disruption and sound conduction problems associated with mechanical tapping. The system can detect force magnitude and direction, providing reliable input while maintaining uninterrupted audio output.
3Measurement precision
If force electrodes are made movable to detect force magnitude, then non-binary force amounts can be determined, but the device structure becomes more complex
Solution Approach 1:
The patent uses a flexible circuit board to mount the force electrodes, allowing the electrodes to move relative to each other in response to applied force. The flexible circuit enables precise force measurement through capacitance changes while maintaining a compact, integrated structure. This approach achieves high measurement precision for force detection without significantly increasing device complexity, as the flexible circuit can be easily integrated into the earphone housing.
Solution Approach 2:
The patent integrates the force electrodes and flexible circuit within the existing earphone housing structure. The force input surface is incorporated into the housing, and the electrodes are nested within the compact space of the earphone body. This nesting approach allows for precise force detection capability while minimizing the increase in overall device complexity and maintaining a sleek, compact form factor.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables earphones to be activated by force without tapping, improving power usage and reducing false inputs, thus enhancing user experience and battery life while maintaining uninterrupted audio output.
Implementation Method 1
A non-binary amount of a force applied to a force input surface defined by a housing of the earphone is determinable using a change in a mutual capacitance between first and second force electrodes
Implementation Method 2
A spring member disposed within the housing biases the first force electrode towards the housing and allows it to move towards the second force electrode when the force is applied
Implementation Method 3
a deformable material positioned between the flexible circuit and the conductive object operable to deform when a force is applied to the input surface
Data Source
AI summary
An earphone includes a speaker housing; a speaker positioned in the speaker housing; a stem extending from the speaker housing, the stem defining an input surface; a conductive object disposed within the stem; a flexible circuit positioned between the stem and the conductive object; a member positioned between the flexible circuit and the conductive object operable to allow the flexible circuit to move with respect to the stem; a force sensor electrode disposed within the flexible circuit; and a controller operable to determine an input to the earphone using a change in capacitance detected using the force sensor electrode, the change in capacitance corresponding to a non-binary amount of a force applied to the input surface. In some examples, the earphone further includes a touch sensor electrode disposed within the flexible circuit.