Capacitive Earphone Stem Input Without Tapping Interference
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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
1Adaptability or versatility
If mechanical input devices (buttons, dials, switches) are incorporated into earphones, then input functionality is improved, but ease of operation deteriorates because users cannot see the input devices when worn
Solution Approach 1:
The patent replaces mechanical input devices (buttons, dials, switches) with a capacitive sensing system that detects touch and force applied to the earphone housing. The controller monitors capacitance changes between electrodes to detect user input, eliminating the need for visible mechanical components while maintaining input functionality.
2Ease of operation
If tapping input mechanism is used, then ease of operation is improved, but harmful factors increase due to sound disruption and microphone interference
Solution Approach 1:
The patent substitutes the tapping mechanism (which causes acoustic disruption) with a capacitive force sensing system. The system detects force applied to the housing through capacitance changes between electrodes, allowing input without mechanical impact that would disrupt audio output or interfere with microphones.
Solution Approach 2:
The patent introduces capacitance sensing as an intermediary between user input and device control. Instead of direct mechanical tapping that disrupts audio, the system uses electrical field changes (capacitance) to detect force applied to the housing, providing a non-intrusive input method that doesn't interfere with audio playback or microphone functionality.
3Device complexity
If force electrodes are positioned close together, then device complexity is reduced, but measurement precision deteriorates due to interference between electrodes
Solution Approach 1:
The patent introduces a deformable material as an intermediary between closely-spaced force electrodes. This material deforms under applied force, changing the capacitance between electrodes in a measurable way while preventing direct electrical interference between the electrodes, thus enabling precise force detection with simple electrode configurations.
4Measurement precision
If continuous force detection is performed, then measurement precision is improved, but power consumption increases
Solution Approach 1:
The patent implements periodic sampling of capacitance values between force electrodes rather than continuous monitoring. The controller measures capacitance at intervals, determining force applied to the housing while conserving battery power. This periodic measurement approach maintains adequate detection precision while significantly reducing power consumption compared to continuous monitoring.
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 preventing sound disruption and microphone interference.
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
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
Data Source
AI summary
A stylus 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.