Wearable Optical Sensing With Narrow-Beam Light for Stray Light Control
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Solution Overview
Problem
Wearable devices face challenges in collecting high-quality biometric data due to internal stray light and limited penetration of optical signals, which is exacerbated by the use of wide-beam optical signals, particularly in smaller form factors like wearable rings.
Innovation Solution
Employing narrow-beam optoelectronic-transmitters that emit optical signals with a full-width half-measure angular spread less than 20°, reducing internal stray light and increasing signal penetration into the skin, while allowing for smaller device designs and improved data quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If wide-beam optical signals are used, then the optical signals can cover a larger area, but internal stray light increases and penetration depth decreases
Solution Approach 1:
The patent changes the beam angle parameter from wide-beam (greater than 80 degrees) to narrow-beam (less than 20 degrees), which fundamentally alters the optical signal characteristics to reduce internal stray light while maintaining effective tissue penetration and coverage
2Area of stationary object
If wide-beam optical signals are used, then the optical signals can cover a larger area, but penetration depth into skin decreases
Solution Approach 1:
The patent changes the beam angle parameter from wide-beam to narrow-beam, which improves the penetration depth by reducing scattering and allowing more light to reach deeper tissue layers while maintaining adequate coverage area
3Object-generated harmful factors
If optoelectronic-transmitters are placed at large distances from optoelectronic-detectors, then internal stray light can be reduced, but device manufacturing complexity increases
Solution Approach 1:
Instead of increasing the distance between transmitters and detectors to reduce stray light, the patent changes the beam angle parameter to narrow-beam, which achieves the same goal of reducing internal stray light while maintaining compact device geometry and simplifying manufacturing
4Object-generated harmful factors
If narrow-beam optoelectronic-transmitters are used, then internal stray light is reduced and penetration depth increases, but the beam covers a smaller area
Solution Approach 1:
The patent changes the beam angle parameter to narrow-beam (less than 20 degrees), which reduces internal stray light and increases penetration depth. The smaller coverage area is acceptable for wearable devices where compact form factor and high data quality are prioritized over extensive coverage
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
Enhances biometric data collection quality and reduces manufacturing complexity by minimizing internal stray light and enabling deeper signal penetration, thus improving accuracy and battery life in wearable devices.
Implementation Method 1
transmitting optical signals into the skin of the user and measuring various characteristics of the optical signals reflected back into optoelectronic-detectors
Data Source
AI summary
Methods, systems, and devices for operating a wearable device are described. A wearable device may include an optoelectronic-transmitter configured to output an optical signal with a narrow angular spread. The optoelectronic-transmitter may be at least partially covered with a material protrusion that has at least one dimension based on the angular spread. The wearable device may include an aperture within an inner surface of a housing of the wearable device. The aperture may be configured to enable propagation of the optical signal through the housing, and a width of the aperture may be based on the angular spread such that the aperture permits propagation of the optical signal within the angular spread. An optoelectronic-detector configured to receive the optical signal may be disposed at a distance from the optoelectronic-transmitter that is based on the angular spread.