Temple-Embedded Optical Sensors for Heart Rate Detection
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Solution Overview
Problem
Conventional heart rate monitors are bulky, uncomfortable, and often inaccurate due to requiring continuous skin contact, which can be disrupted by movement, sweat, and dirt, especially when using photodiodes and LEDs on the wrist.
Innovation Solution
A computerized eyewear system with two optical sensors embedded in the temples, one with a narrow field of detection focused on the heart rate area and another with a wider field to measure noise deltas, allowing for accurate heart rate detection by subtracting noise from raw heart rate measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional heart rate monitors use photodiodes and LEDs that contact skin on the wrist, then heart rate can be measured, but the measurements become inaccurate due to continuous skin contact requirements
Solution Approach 1:
The patent introduces an intermediary mechanism by using optical sensors that detect heart rate through temporal artery pulsation at the temple rather than direct skin contact at the wrist. This intermediary location (temple area) allows for indirect measurement that is less susceptible to movement artifacts, sweat, and dirt interference while maintaining measurement accuracy through optical detection of blood flow changes.
Solution Approach 2:
The patent replaces the mechanical contact-based measurement system (photodiodes pressing against wrist skin) with an optical detection system that measures light absorption changes in the temporal artery. This substitution eliminates the need for continuous mechanical skin contact, thereby reducing measurement errors caused by device movement, sweat, and dirt accumulation.
2Measurement precision
If chest strap monitors are used for accurate heart rate detection, then measurement accuracy is improved, but device complexity and comfort are worsened
Solution Approach 1:
The patent merges the heart rate measurement function directly into the eyewear structure itself, eliminating the need for separate chest straps and wireless communication devices. The optical sensors are integrated into the temple pieces of the eyewear, allowing heart rate monitoring to be performed as part of the regular eyewear without requiring additional components or complex wireless communication systems.
Solution Approach 2:
The eyewear structure serves multiple functions: it provides vision correction/protection while simultaneously functioning as a heart rate monitor. The temple pieces that normally only support the eyewear structure are repurposed to house optical sensors for physiological monitoring, creating a multi-functional device that reduces overall system complexity.
3Measurement precision
If chest strap monitors are used for accurate heart rate detection, then measurement accuracy is improved, but comfort and ease of operation are worsened
Solution Approach 1:
The patent combines the heart rate monitoring function with the eyewear structure, eliminating the need for separate chest straps that must be accurately positioned and continuously worn. The sensors are integrated into the temple pieces, which are already part of the eyewear the user is wearing for vision purposes, thereby improving comfort and ease of operation.
Solution Approach 2:
The patent uses the temple area of the eyewear as an intermediary location for sensor placement, which is more comfortable than chest straps. The temple pieces are designed to rest on the ears and fit naturally against the head, providing a comfortable and stable position for optical sensors without requiring tight straps or continuous adjustment.
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 system provides a comfortable and accurate method for heart rate monitoring by distinguishing heart rate pulses from noise, using LEDs and photodiodes to measure distance changes over time, even during movement, enhancing reliability and usability.
Implementation Method 1
measure the light absorption in the blood flowing through the wrist
Implementation Method 2
measure the distance between the sensor and the skin of the wearer. The difference in the distance over time is representative of the heart rate
Implementation Method 3
utilize photodiodes and LEDs that contact a person's skin to measure the light absorption in the blood flowing through the wrist
Data Source
AI summary
Computerized eyewear and corresponding methods measure a wearer's heart rate using a first optical sensor and a second optical sensor at least partially embedded in an eyewear temple. The first optical sensor transmits a first signal to a temple of the wearer and the second optical sensor transmits a second signal to the temple of the wearer. Reflections of the first signal are used to measure a raw heart rate delta and reflections of the second signal are used to measure a noise delta. The raw heart rate delta and the noise delta are used to determine a measured heart rate of the wearer of the computerized eyewear.