Multi-mode Sensor Orientation Detection for Wearables
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Solution Overview
Problem
Existing wearable devices face challenges in accurately determining their relative surface orientation to a user's body surface, particularly when worn loosely or on surfaces with non-uniform optical qualities, leading to unintended device locking or power state changes.
Innovation Solution
A multi-mode sensor system with an array of light emitters and photodetectors that generate multiple light paths across various wavelengths, allowing for precise location and orientation measurement by computing data from different light paths and wavelengths, and using proximity curve data to determine surface distance and tilt angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single proximity sensor is used to detect body surface contact, then the device structure is simple, but the measurement precision deteriorates when worn loosely or on non-uniform surfaces
Solution Approach 1:
The sensor is divided into multiple independent emitter-detector pairs, each capable of measuring light path characteristics. This segmentation allows the system to acquire multiple measurement dimensions simultaneously, improving location and orientation detection accuracy without requiring a completely new sensor architecture.
Solution Approach 2:
The patent transitions from single-point proximity detection to multi-dimensional light path analysis by creating multiple emitter-detector pairs with different separations and wavelengths. This adds spatial and spectral dimensions to the measurement, enabling robust detection of both location and orientation relative to the body surface.
2Measurement precision
If multiple light paths and wavelengths are used to improve measurement robustness, then the measurement precision improves, but the device complexity increases
Solution Approach 1:
Multiple emitter-detector pairs with different configurations serve multiple measurement functions simultaneously. The same sensor array can detect location, orientation, and compensate for surface optical variations by analyzing light paths across different wavelengths and separations, making the system universally applicable to various wearing conditions.
Solution Approach 2:
The system varies measurement parameters (light wavelength, emitter-detector separation distance) to optimize performance for different body surface conditions. By changing these parameters across multiple emitter-detector pairs, the system can adapt to pigmented surfaces, loose wearing, and non-uniform body geometries without adding complex processing hardware.
3Reliability
If proximity sensors detect any body contact, then the device can determine wear state, but false locking occurs on pigmented or non-uniform surfaces
Solution Approach 1:
The patent replaces single-wavelength optical detection with multi-wavelength optical analysis. By examining the spectral response across multiple wavelengths, the system can distinguish between true body contact and false contacts on pigmented surfaces, replacing simple optical detection with spectroscopic analysis.
Solution Approach 2:
The light paths across multiple wavelengths act as intermediaries that mediate between the sensor and the body surface. These multi-wavelength light paths provide additional information about the surface optical properties, allowing the system to filter out false positives from pigmented surfaces while maintaining reliable wear detection.
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 approach enables robust and accurate detection of wearable device orientation relative to the body surface, preventing unintended locking or power state changes, even on pigmented or non-uniform surfaces, and allows for precise determination of whether the device is worn or removed.
Implementation Method 1
The wearable devices and methods may include a multi-mode sensor including light emitters and photodetectors that are configured to generate multiple light paths across one or more light wavelengths
Implementation Method 2
They generally emit electromagnetic radiation, measure the return signal, and identify the location of the target based on the profile of the return signal
Data Source
AI summary
The present disclosure relates generally to wearable devices and methods for detecting relative surface orientation. The wearable devices and methods may include a multi-mode sensor comprising emitter-detector combinations (e.g., sets or pairs) that have various spacings between the light emitter and the photodetector. Proximity curves can be generated based upon the various emitter-detector pair spacings, and used to assess surface distance and angular orientation of the wearable device to a body surface of an individual. In some variations, location and/or orientation of the device relative to the body surface is determined based on mapping data acquired by one or more emitter-detector pairs to surface distance (z distance) values based on proximity curve data stored in a memory of a device controller.