Earphone Force-Sensing Stem for Noise-Free Local 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, 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 locally without external devices, but the input devices become difficult to operate when worn and may conduct sound disrupting audio output
Solution Approach 1:
The patent replaces mechanical input devices (buttons, dials, switches) with a force-sensitive capacitive sensing system. The force sensor electrodes detect applied force through capacitance changes, eliminating mechanical components that conduct sound. This substitution maintains local control capability while preventing sound conduction and noise disruption to audio output.
Solution Approach 2:
The patent introduces a dielectric layer and deformable material as intermediaries between the force application point and the force sensor electrodes. These intermediaries transmit mechanical force as capacitive changes without conducting acoustic waves, allowing force input detection while blocking sound transmission paths that would disrupt audio output.
2Measurement precision
If force sensor electrodes are positioned close to each other for sensitive force detection, then force detection precision improves, but the risk of false inputs and noise interference increases
Solution Approach 1:
The patent uses a deformable material and dielectric layer as intermediaries between the force sensor electrodes and the external environment. These intermediaries filter out minor vibrations and noise while transmitting significant force applications, thereby reducing false inputs while maintaining force detection precision through proper electrode placement and capacitance measurement.
Solution Approach 2:
The patent employs a deformable material that dynamically responds to applied force, changing its physical properties (such as density or elastic modulus) in response to force magnitude. This dynamic response allows the system to distinguish between significant force inputs and minor vibrations, improving reliability by reducing false inputs while maintaining precision for valid force measurements.
3Adaptability or versatility
If a spring member is used to bias the force electrode for force detection, then the force sensor can detect non-binary force amounts, but the device complexity increases
Solution Approach 1:
The patent integrates the spring member's mechanical biasing function with the capacitive sensing function into a unified force detection system. The spring member not only provides the necessary mechanical bias to position the force sensor electrode but also works in conjunction with the deformable material to translate force applications into capacitive changes. This multi-functionality reduces overall system complexity compared to using separate mechanisms for biasing and sensing.
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 and noise disruption, while maintaining audio quality and extending battery life.
Implementation Method 1
A non-binary amount of a force applied to a force input surface defined by a housing 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
This flexible circuit may flex to allow the first force electrode to move toward the second force electrode when the force is applied. This flexible circuit may also flex to allow the first force electrode to move away from the second force electrode when the force is no longer applied
Implementation Method 4
a shield. The shield is disposed between the touch sensor electrode and the force sensor electrode
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.