Earphones On-Head Detection Using Orientation Sensors
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Solution Overview
Problem
Existing earphones, particularly those with open-ear form factors, face challenges in reliably detecting when they are positioned on a user's head due to variations in ear shapes and adjustments during use, making it difficult to position sensors that consistently contact the user's skin.
Innovation Solution
The implementation of a pair of earphones with on-head detection using orientation sensors within each earpiece, where the controller determines the on-head status by analyzing whether the orientation signals from both earpieces represent a common change in orientation, allowing for the suspension or initiation of earphone functions accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional skin-contacting sensors are used in open-ear earphones, then the earphones can detect when they are positioned on the user's head, but the detection reliability deteriorates due to variations in ear shapes and adjustments during use
Solution Approach 1:
The patent replaces mechanical skin-contacting sensors with orientation sensors (IMUs) that detect head movement through inertial measurement. Instead of relying on physical contact with the skin, the system uses gravitational and inertial forces to determine earphone position, eliminating the need for consistent skin contact while maintaining detection reliability across different ear shapes.
Solution Approach 2:
The patent changes the detection parameter from skin contact status to orientation and movement characteristics. By measuring angular rates and comparing them against thresholds, the system determines on-head status based on the relationship between the two earpieces' orientation changes rather than direct contact, enabling adaptation to various ear geometries.
2Reliability
If sensors are positioned to consistently contact the user's skin, then on-head detection can be achieved, but the device complexity increases due to the need for precise sensor positioning
Solution Approach 1:
The patent eliminates the complex mechanical positioning problem by substituting skin-contacting sensors with orientation sensors that measure head movement indirectly. The IMUs detect gravitational and inertial forces without requiring precise anatomical positioning, significantly simplifying the device while maintaining detection accuracy.
Solution Approach 2:
The patent introduces an intermediary approach by using the relationship between the two earpieces' orientation changes as a mediator to determine on-head status. Instead of directly measuring skin contact, the system uses the correlated movement patterns of both earpieces as an indirect indicator, eliminating the need for complex single-sensor positioning.
3Reliability
If the earphones use orientation sensors to detect common change in orientation, then the on-head status can be determined reliably, but the measurement precision requirements increase
Solution Approach 1:
The patent applies partial action by using a simplified threshold-based comparison of orientation changes rather than requiring high-precision continuous measurement. The system compares the difference in angular rates between the two earpieces against a predetermined threshold, which provides sufficient accuracy for on-head detection without demanding excessive measurement precision.
Solution Approach 2:
The patent implements feedback through continuous monitoring of orientation signals from both earpieces and comparing their changes over time. The system uses the feedback from these comparisons to dynamically determine on-head status, adjusting detection sensitivity based on the observed movement patterns rather than relying on fixed high-precision thresholds.
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 reliable on-head detection for earphones across various form factors, including open-ear wearables, by using orientation sensors to determine if the earpieces are attached to a rigid body, effectively managing earphone functions based on the detected status.
Implementation Method 1
a first orientation sensor housed in the first earpiece, the first orientation sensor outputting a first orientation signal representing a first orientation of the first earpiece
Data Source
AI summary
A pair of earphones with on-head detection, including: a first earpiece housing a first orientation sensor, the first orientation sensor outputting a first orientation signal representing a first orientation of the first earpiece; a second earpiece housing a second orientation sensor, the second orientation sensor outputting a second orientation signal representing a second orientation of the second earpiece; a controller configured determine an on-head status of the first earpiece and the second earpiece based, at least in part, on whether the first orientation signal and the second orientation signal represent a common change in orientation, wherein the controller is further configured to begin or suspend at least one function of the pair of earphones upon determining a change in the on-head status of at least one the first earpiece or the second earpiece.