Optical Guide for Uniform Tissue Illumination in Portable Physiological Sensors
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Solution Overview
Problem
Portable devices for measuring physiological quantities like heart rhythm face challenges due to localized defects in organic tissue, such as moles or hairs, which affect light emission absorption, leading to degraded measurement quality, and existing solutions increase energy consumption and manufacturing costs.
Innovation Solution
Incorporating an optical element that guides light emission by total internal reflection to distribute it over a broader area, optimizing illumination and detection zones, and using a structured optical guide with micro-prismatic structures to channel light effectively, reducing the impact of localized defects while minimizing energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple light sources are used to illuminate a larger area of organic tissue, then the illumination area is increased and measurement reliability is improved, but energy consumption increases and manufacturing costs increase
Solution Approach 1:
The optical guide is divided into multiple light-guiding portions or channels, each directing light to a specific zone on the organic tissue surface. This segmentation allows a single light source to effectively illuminate multiple areas simultaneously, achieving the effect of multiple light sources without the associated energy consumption and cost increases.
Solution Approach 2:
An optical guide structure acts as an intermediary between the light source and the organic tissue. This optical guide distributes light from a single source across multiple zones on the tissue surface, eliminating the need for multiple direct light sources while maintaining reliable measurement across the illuminated area.
2Area of stationary object
If multiple light sources are arranged to cover a larger area, then the illumination area is increased, but device complexity and construction difficulty increase
Solution Approach 1:
Multiple light-guiding functions are merged into a single integrated optical guide structure. Instead of separately positioning and connecting multiple light sources, the optical guide combines all light distribution functions in one component, significantly reducing construction complexity while maintaining large-area illumination capability.
Solution Approach 2:
The optical guide serves as an intermediary that simplifies the system architecture. Rather than directly managing multiple light sources and their individual connections, the single optical guide mediates light distribution across the entire illumination area, reducing construction complexity.
3Use of energy by moving object
If a single light source is used, then energy consumption is reduced, but the illumination area remains limited and measurement reliability deteriorates due to localized tissue defects
Solution Approach 1:
The optical guide is segmented into multiple light-guiding portions that distribute light from a single source to multiple zones on the organic tissue. This segmentation allows the system to maintain low energy consumption while improving measurement reliability by illuminating a broader area that averages out localized tissue defects.
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 solution provides uniform and efficient illumination and detection, optimizing energy use and reducing the influence of tissue defects, making the device more suitable for portable applications with improved measurement accuracy.
Implementation Method 1
an optical element forming a guide coupled to the at least one light source for guiding the light emission from the source by total internal reflection in a substantially parallel direction to the surface of the organic tissue to be illuminated
Data Source
AI summary
A portable instrument for measuring a physiological quantity arranged to contact with the surface of organic tissue includes, essentially arranged in the same plane: an illumination device including at least one light source with an illumination surface for subjecting a portion of organic tissue to light emission in at least one wavelength range; and a detection device distant from the illumination device for detecting intensity of light emission produced by the illumination device after propagation in the organic tissue. The illumination device includes an optical element forming a guide coupled to the at least one light source for guiding light emission from the source by total internal reflection in a substantially parallel direction to the surface of the organic tissue and for distributing light emission into several illumination zones on the surface of the organic tissue over a substantially broader area than the illumination surface of the light source.