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 tapping to activate them can disrupt audio output and conduct sound, leading to unpleasant experiences and potential interference with microphones.
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 false inputs by using a spring member to bias the force electrode and a flexible circuit to detect touch and force simultaneously.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If mechanical input devices (buttons, dials) 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 touch sensor system. The sensor detects changes in capacitance caused by finger proximity or contact, allowing users to control earphones without visible mechanical components. This substitution maintains input functionality while dramatically improving ease of operation when the earphones are worn.
2Ease of operation
If tapping input method is used, then activation is simplified, but harmful factors increase due to sound conduction and interference with microphones
Solution Approach 1:
The patent replaces the mechanical tapping input method with a capacitive touch detection system. The capacitive sensor detects the electrostatic field changes caused by finger proximity, allowing activation without physical contact that would conduct sound. This eliminates the harmful acoustic interference while maintaining simple activation.
Solution Approach 2:
The patent introduces an intermediary detection mechanism (capacitive sensing) between the user and the earphone activation. Instead of direct mechanical contact that conducts sound, the system detects electrostatic field changes through the air or through non-conductive materials, acting as an intermediary that prevents sound conduction while still detecting user intent.
3Volume of moving object
If force electrodes are positioned close to each other, then device size is reduced, but measurement precision deteriorates due to difficulty in detecting non-binary force amounts
Solution Approach 1:
The patent changes the detection parameter from simple capacitance to differential capacitance measurement. By measuring the difference in capacitance between two electrodes rather than absolute values, the system can detect subtle force variations even when electrodes are closely spaced. This parameter transformation maintains compact size while achieving non-binary force measurement precision.
Solution Approach 2:
The patent uses a spring member that provides a biasing force, creating a predetermined initial capacitance state. This partial action (pre-compression) establishes a baseline from which force variations can be detected, enabling precise measurement of additional forces even in a compact configuration where electrodes must be close together.
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 interference, allowing for more accurate input detection and enhanced user experience by preventing false inputs and maintaining audio quality.
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
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.