ATR Prism Infrared Biosensor for Low-Cost Blood Sugar Measurement

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Solution Overview

Problem

Conventional biological material measuring apparatuses, such as those using infrared light to measure blood sugar levels, face challenges with high costs and limited accuracy due to the need for wavelength tunable lasers and absorption issues by water in the body.

Innovation Solution

A biological material measuring apparatus that includes an infrared light source unit, a prism, and a light position detector to radiate and detect infrared light in specific wavelength regions, eliminating the need for wavelength tunable lasers by using a wideband quantum cascade laser and a plasmon-based light position detector for accurate measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a wavelength tunable laser is used to measure at multiple wavelengths for improved accuracy, then measurement precision is improved, but device cost and size increase

Engineering Contradiction:

Improvemeasurement accuracyVSAvoiddevice cost and size

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent changes the parameter of light source from a wavelength-tunable laser to a fixed-wavelength laser combined with an ATR prism system. This parameter change allows the system to achieve accurate biological material measurement without requiring complex wavelength tuning mechanisms, thereby reducing device cost and size while maintaining measurement precision through the ATR effect's inherent wavelength-selective properties

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent extracts the wavelength selection function from the light source itself and implements it through the ATR prism system instead. By separating the wavelength selection mechanism from the laser source, the system achieves multi-wavelength measurement capability without requiring a complex tunable laser, thus resolving the contradiction between measurement accuracy and device simplicity

Inventive Principle:

Principle #2Taking out (Extraction)

2Measurement precision

If infrared light is used to detect biological materials, then measurement capability is enabled, but water absorption in the body limits light penetration depth

Engineering Contradiction:

Improvedetection capabilityVSAvoidwater absorption

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful effect of water absorption into a beneficial feature by utilizing the ATR (Attenuated Total Reflection) effect. The ATR prism is designed to exploit the absorption characteristics of water and biological materials at specific infrared wavelengths, transforming the absorption limitation into a measurement advantage where absorption strength correlates with biological material concentration, enabling accurate detection despite limited penetration

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The ATR prism acts as an intermediary between the infrared light source and the biological material. It facilitates light-biological material interaction by creating an evanescent wave field at the prism-biological material interface, allowing measurement without requiring deep light penetration into the body, thus overcoming the water absorption limitation while maintaining detection capability

Inventive Principle:

Principle #24Intermediary (Mediator)

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 allows for low-cost, high-accuracy measurement of biological materials by generating a refractive index gradient in the prism, enabling precise detection of biological materials without the need for expensive wavelength tunable lasers.

Implementation Method 1

an infrared light source unit to radiate infrared light in entirety or part of a wavelength region including absorption wavelengths of a biological material

Methodology Applied

Scientific EffectQuantum cascade laser emission: Laser

Implementation Method 2

a prism to cause the infrared light radiated from the infrared light source unit to pass therethrough and emit the infrared light to a living body surface

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 3

a light position detector to detect a path of light from the light source by detecting light from the light source which is emitted from the prism

Methodology Applied

Scientific EffectLight detection: Photoelectric Effect

Implementation Method 4

an infrared photodetector to detect infrared light of at least one wavelength which is emitted from the ATR prism

Methodology Applied

Scientific EffectInfrared detection: Absorption (EM radiation)

Data Source

PatentUS11832942B2Biological material measuring apparatus

Publication Date: 2023.12.05 MITSUBISHI ELECTRIC CORP

AI summary

A biological material measuring apparatus includes an infrared light source unit to radiate infrared light in entirety or part of a wavelength region including absorption wavelengths of a biological material, a prism to cause the infrared light radiated from the infrared light source unit to pass therethrough and emit the infrared light to a living body surface while being in contact with the living body surface, a light source to radiate light of a wavelength in a visible light region or a near infrared region to the prism, and a light position detector to detect a path of light from the light source by detecting light from the light source which is emitted from the prism.