Luminescent Concentrator Pulse Sensor Light Collection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional pulse sensors have low efficiency due to a small fraction of produced light reaching the light detector, resulting in a weak signal and the need for a thin design in applications like wristwatches.
Innovation Solution
A pulse sensor design incorporating a luminescent concentrator with an entry face larger than the exit face, filled with fluorescent material, which collects and converts modulated scattered light, increasing its intensity and guiding it to a light detector for improved efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional pulse sensor design is used with light sources and light detector separated by housing walls, then direct light contamination is prevented, but only a small fraction of produced light reaches the light detector resulting in low efficiency
Solution Approach 1:
The patent introduces an optical guide element as an intermediary component between the light source and light detector. This optical guide collects scattered light from the tissue and transports it to the detector, thereby increasing the fraction of detected light without compromising the separation between light source and detector that prevents direct light contamination.
2Length of moving object
If the pulse sensor is designed to be thin for wristwatch applications, then wearability is improved, but the signal strength becomes weaker due to reduced space for optical components
Solution Approach 1:
The patent employs an optical guide element that extends in the lateral dimension rather than requiring increased thickness. The optical guide collects light over a larger area and transports it through a compact structure, enabling thin sensor design while maintaining adequate signal strength at the detector.
3Productivity
If a larger area light detector is used to capture more scattered light, then detection efficiency is improved, but the device complexity and housing space requirements increase
Solution Approach 1:
The patent segments the optical detection function into two parts: light collection at the tissue interface and light transport via optical guide to a compact detector. This segmentation allows the use of a smaller detector area while maintaining detection efficiency, as the optical guide concentrates the scattered light onto the detector surface.
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 use of a luminescent concentrator significantly enhances the efficiency of the pulse sensor by increasing the proportion of scattered light that reaches the detector, resulting in a stronger signal and allowing for a potentially thinner design.
Implementation Method 1
at least some of the modulated scattered light enters into the luminescent concentrator through the entry face, that the light that has entered is converted by the fluorescent material, the converted light being modulated in a manner corresponding to the modulated scattered light
Data Source
AI summary
In an embodiment a pulse sensor includes two light sources configured to emit light in a direction of a perfused tissue of a living being so that the perfused tissue scatters the light and so that the scattered light is modulated on basis of a pulse of the living being, at least one luminescent concentrator including an entry face, an exit face smaller than the entry face, and a fluorescent material arranged in a light path between the entry face and the exit face, wherein the luminescent concentrator is configured to receive at least some of the modulated scattered light entering through the entry face, convert the entered light by the fluorescent material and emit the modulated converted light from the exit face, and one light detector configured to detect at least some of the modulated converted light emerging from the exit face, wherein, in plan view, the luminescent concentrator is strip-shaped and extends perpendicular to a connecting line between the two light sources, wherein side faces of the luminescent concentrator facing the light sources are concave, and wherein corresponding side faces extend at least partially around the light sources.