Capacitive Force-Sensing Earphone Input Without Tap Noise
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Solution Overview
Problem
Conventional earphones with mechanical input devices are difficult to operate when worn, as users cannot see the 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 force input surface using a change in mutual capacitance between first and second force electrodes, with a spring member biasing the first force electrode towards the housing, allowing it to move towards the second electrode when force is applied, enabling activation without external mechanical input devices or tapping.
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 activated and controlled, but the devices become difficult to operate when worn as users cannot see the input devices and tapping can disrupt audio output and conduct sound
Solution Approach 1:
The patent replaces traditional mechanical input devices (buttons, dials, switches, sliders) with a force sensing system that detects applied force through capacitance changes. This substitution eliminates the need for visible mechanical components and tapping actions, allowing users to activate earphones by applying gentle force without disrupting audio output or conducting sound.
Solution Approach 2:
The patent changes the detection parameter from mechanical position or tactile feedback to force magnitude detection through capacitance measurement. By measuring the non-binary amount of force applied (rather than simple presence/absence), the system can distinguish between intentional activation and accidental contact, enabling operation without visible mechanical components.
2Ease of operation
If force electrodes and spring members are added to detect force magnitude, then activation without tapping is enabled, but the device complexity increases
Solution Approach 1:
The patent integrates multiple functions into the force sensing system: the force electrodes and spring members not only detect force magnitude for activation but also provide mechanical biasing and structural support. This multi-functionality reduces the need for separate components, thereby limiting the increase in device complexity despite adding force detection capability.
Solution Approach 2:
The spring member acts as an intermediary element that translates applied force into electrode displacement and capacitance change. This intermediary mechanism provides a reliable force-to-signal conversion while maintaining a compact structure, balancing the need for accurate force detection with constraints on device complexity.
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 allows for efficient activation of earphones by force without disrupting audio output, improves power usage, and reduces false inputs by distinguishing between intentional and accidental force applications, enhancing user experience and battery life.
Implementation Method 1
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 2
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
Data Source
AI summary
An earphone includes a housing that defines a force input surface opposite a touch input surface. A spring member in the housing includes a first arm that biases a touch sensor toward the touch input surface. The spring member also includes a second arm that biases a first force electrode toward the housing and allows the first force electrode to move toward a second force electrode when a force is applied to the force input surface. A non-binary amount of the force is determinable using a change in a mutual capacitance between the first force electrode and the second force electrode. The mutual capacitance between the first force electrode and the second force electrode may be measured upon detecting a touch using the touch sensor.