Light Guide Plate Segmentation for Blood Component Measurement
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Solution Overview
Problem
Existing information acquisition apparatuses face challenges in achieving a high signal-to-noise ratio due to excessive noise light when measuring blood components noninvasively, which hinders accurate image acquisition and component detection.
Innovation Solution
Incorporating a light guide plate with refractive indices differing between its first and second portions, strategically positioned to enhance the reflection and transmission of light, thereby increasing the signal light received while reducing noise light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional light receiving device is used to detect light from the biological body, then light detection is possible, but the signal-to-noise ratio decreases due to excessive noise light
Solution Approach 1:
The light guide plate is divided into multiple regions with different refractive indices: a first region (higher refractive index) positioned over the light emitting device, a second region (lower refractive index) positioned over the light receiving device, and a third region (higher refractive index) at the peripheral portion. This segmentation creates refraction interfaces that selectively guide signal light while blocking noise light paths.
Solution Approach 2:
Different regions of the light guide plate are assigned different refractive index characteristics tailored to their specific functions: the first region focuses emitted light into the biological body, the second region allows reflected signal light to reach the detector, and the third region blocks oblique noise light. This local differentiation of optical properties optimizes the signal-to-noise ratio at each location.
2Measurement precision
If light is emitted toward the biological body to obtain image information and blood component information, then measurement capability is achieved, but noise light enters the light receiving device reducing measurement accuracy
Solution Approach 1:
The light guide plate acts as an intermediary optical element between the light emitting device and the biological body, and between the biological body and the light receiving device. It mediates the light paths by refracting emitted light to improve penetration and by refracting reflected light to enhance detection, while simultaneously blocking noise light paths.
Solution Approach 2:
The refractive index parameter is strategically varied across different regions of the light guide plate. The first region has a higher refractive index to focus and direct emitted light into the biological body at optimal angles. The second region has a lower refractive index to allow reflected signal light to exit and reach the light receiving device efficiently.
3Measurement precision
If the light guide plate uses uniform refractive index throughout, then manufacturing is simplified, but light control capability is insufficient to achieve high signal-to-noise ratio
Solution Approach 1:
Different regions of the light guide plate are assigned different refractive index characteristics tailored to their specific functions: the first region (higher refractive index) focuses emitted light into the biological body, the second region (lower refractive index) allows reflected signal light to reach the detector, and the third region (higher refractive index) blocks oblique noise light. This local differentiation of optical properties optimizes the signal-to-noise ratio at each location.
Solution Approach 2:
The light guide plate is divided into multiple regions with different refractive indices: a first region (higher refractive index) positioned over the light emitting device, a second region (lower refractive index) positioned over the light receiving device, and a third region (higher refractive index) at the peripheral portion. This segmentation creates refraction interfaces that selectively guide signal light while blocking noise light paths.
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 configuration improves the signal-to-noise ratio, enabling more reliable identification of blood vessel positions and stable measurement of blood components by minimizing noise light and maximizing signal light reception.
Implementation Method 1
The light guide plate has a first portion and a second portion having refractive indices different from each other... at least part of light traveling obliquely with respect to the direction described above is reflected off the interface between the first portion and the second portion
Data Source
AI summary
An biological body information acquisition apparatus includes an imager including light emitting devices that are arranged in a plane and emit light toward a human body and light receiving devices that are arranged in a plane and receive light from the human body and a light guide plate that is layered on the imager on the side thereof facing the human body and has light transmissivity in the direction of a normal to the light receiving devices and the light emitting devices. The light guide has a first portion (holes) and a second portion (substrate) that are arranged in a plane and have refractive indices different from each other. The first portion (holes) is so disposed as to coincide with the light receiving devices in a plan view, and the second portion (substrate) is so disposed as to coincide with the light emitting devices in the plan view.