Earphone Force-Sensing Stem for Tap-Free Input 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 tapping to activate them 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 housing input surface using a change in capacitance between first and second force electrodes, allowing activation without external mechanical input devices and reducing tapping noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If mechanical input devices (buttons, dials, switches, sliders) are incorporated into earphones, then the earphones can be controlled locally without external devices, but the input devices become difficult to operate when worn because users cannot see them
Solution Approach 1:
The patent replaces mechanical input devices with a force sensor that detects force applied to the housing. This substitution eliminates the need for visible mechanical buttons, dials, switches, or sliders while maintaining local control capability. The force sensor detects user input through force applied to the housing surface, providing an invisible yet operable input mechanism.
2Ease of operation
If tapping is used to activate input devices, then the earphones can be activated without external devices, but tapping can disrupt audio output and conduct sound, leading to unpleasant experiences and potential microphone interference
Solution Approach 1:
The patent replaces tapping-based mechanical input with a force sensor that detects force applied to the housing. This substitution eliminates the harmful acoustic effects of tapping (sound conduction and audio disruption) while maintaining the ability to activate and control the earphones locally. The force sensor provides a non-acoustic input mechanism that does not interfere with audio output or microphone function.
3Measurement precision
If force electrodes are positioned close to each other to detect force, then the force detection sensitivity increases, but the capacitance measurement becomes more difficult due to electrical interference
Solution Approach 1:
The patent introduces a deformable dielectric material positioned between the force electrodes. This dielectric material serves as an intermediary that enhances the capacitance signal in response to applied force while electrically isolating the electrodes from each other. The deformable nature of the dielectric allows it to respond to force by changing the capacitance between electrodes, improving detection sensitivity without causing direct electrical interference between closely positioned electrodes.
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 noise disruption, thus enhancing user experience and battery life while preventing false inputs from head or face contact.
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.