Wearable Oximeter Layout for Motion-Resistant Heart Rate Sensing
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Solution Overview
Problem
Existing heart rate monitors using infrared light are affected by wearer's movements, introducing noise due to relative dislocation of emitters and sensors, and require multiple sensors and emitters, which are costly and prone to malfunction.
Innovation Solution
A device with a plurality of light emitters and sensors arranged to allow multiple observations using fewer sensors, enabling redundant observations and reducing hardware requirements, with emitters emitting light in consecutive order to be detected by a single sensor, and employing mathematical treatments to minimize noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If three pairs of emitter and sensor are used to provide three independent observations for noise removal, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent combines multiple emitter-sensor observations into a single integrated system where one emitter serves multiple sensors and one sensor can detect from multiple emitters. This merging approach achieves the same noise removal capability as three separate pairs while using fewer components, directly resolving the contradiction between measurement precision and device complexity
Solution Approach 2:
The patent creates a universal emitter-sensor system where each emitter can serve multiple sensors and each sensor can detect from multiple emitters. This multi-functionality allows the system to obtain multiple independent observations without requiring three separate dedicated pairs, reducing overall system complexity while maintaining measurement accuracy
2Reliability
If three pairs of emitter and sensor are used to provide redundant observations, then reliability is improved, but manufacturing cost increases
Solution Approach 1:
By merging the functionality of three separate emitter-sensor pairs into an integrated system with fewer components, the patent reduces manufacturing costs while maintaining reliability through the same redundant observation capability. The shared emitter-sensor architecture provides backup pathways without requiring three complete independent pairs
Solution Approach 2:
The patent enables the system to discard failed emitters or sensors and recover functionality by utilizing the remaining operational components. The flexible architecture allows the system to continue providing sufficient observations even when some components fail, maintaining reliability while reducing the need for expensive redundant components
3Measurement precision
If multiple emitters and sensors are used to obtain multiple observations, then measurement precision is improved, but the device becomes more prone to malfunction
Solution Approach 1:
The patent creates a universal system where each emitter and sensor serves multiple functions across different observation pathways. This multi-functionality means that a single component failure does not eliminate an entire observation channel, as the failed component's functionality is distributed across multiple measurement paths, reducing susceptibility to failure while maintaining measurement precision
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
The device achieves accurate heart rate monitoring with robust resistance to malfunction, requiring fewer sensors and emitters, while maintaining or improving performance, and adapting to ambient light conditions.
Implementation Method 1
a plurality of light emitters at least one sensor, the plurality of light emitters arranged such that light from the plurality of light emitters is capable of passing through the body part to arrive at the least one sensor
Implementation Method 2
Skin, tissues, venous blood and arterial blood absorb and reflect parts of this infrared light
Implementation Method 3
The emitter emits infrared light into the limb towards the sensor
Data Source
AI summary
A wearable device suitable for monitoring blood in a body part may be implemented for instance in oximeters for detecting oxygen level in blood, which operates by contrasting the ratio of transmission of visible red light to transmission of infrared light. The ratio of the amount of absorbed red light to the amount of absorbed infrared light indicates the amount of oxygen in the blood. Therefore, in wearable devices having an oximeter function, there may be an emitter emitting red light to the sensor, and an emitter emitting infrared light to the same sensor which is capable of detecting in both ranges of wavelengths. In this case, the red light emitter and the infrared light emitter take turns to emit light.