Fluorescence Sensor With Side-Mounted Photodiode

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Solution Overview

Problem

Conventional fluorescence sensors face challenges in achieving high detection sensitivity due to the trade-off between the area of the air gap region for excitation light transmission and the photoelectric conversion element, which limits the amount of excitation light reaching the indicator layer and subsequently the sensitivity of the sensor.

Innovation Solution

The fluorescence sensor design incorporates a needle-type configuration with a detection substrate featuring a concave portion where the LED element generates excitation light only towards the indicator layer, surrounded by a photodiode element on the side surface, and a light blocking layer to prevent leakage, enhancing the detection of fluorescent light while minimizing noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If the area of the air gap region is increased to transmit more excitation light, then the amount of excitation light reaching the indicator layer is improved, but the area available for the photoelectric conversion element decreases, reducing detection sensitivity

Engineering Contradiction:

Improveamount of excitation lightVSAvoiddetection sensitivity

Core Design Contradiction:

Illumination intensityVSMeasurement precision

Solution Approach 1:

The photoelectric conversion element is positioned on the side surface of the substrate rather than on the top surface, utilizing the vertical dimension and side surface area. This allows the excitation light to pass through the air gap region and reach the indicator layer on the top surface, while the photoelectric conversion element simultaneously captures fluorescent light from the side, resolving the area conflict between light transmission and detection sensitivity

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The substrate acts as an intermediary structure that separates the functions of light transmission and light detection into different spatial dimensions. The top surface accommodates the indicator layer for excitation light transmission, while the side surface accommodates the photoelectric conversion element for fluorescent light detection, allowing both functions to operate optimally without competing for the same area

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If the area of the photoelectric conversion element is increased to improve detection sensitivity, then the detection sensitivity is improved, but the area of the air gap region decreases, reducing the amount of excitation light reaching the indicator layer

Engineering Contradiction:

Improvedetection sensitivityVSAvoidamount of excitation light

Core Design Contradiction:

Measurement precisionVSIllumination intensity

Solution Approach 1:

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The substrate surface is segmented into different functional zones: the top surface is dedicated to the indicator layer for excitation light transmission, while the side surface is dedicated to the photoelectric conversion element for fluorescent light detection. This functional segmentation allows each component to have optimal area without compromising the other

Inventive Principle:

Principle #1Segmentation

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 high detection sensitivity by efficiently directing excitation light to the indicator layer and effectively capturing fluorescent light, resulting in improved sensitivity without increasing the size of the air gap region, thus overcoming the limitations of conventional designs.

Implementation Method 1

an LED element 12, which is a light-emitting element that generates the excitation light E

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 2

the fluorescent pigment in the indicator layer generates fluorescent light with a light amount corresponding to the analyte concentration

Methodology Applied

Scientific EffectPhotoluminescence: Photoluminescence

Implementation Method 3

The photodetector is a photoelectric conversion element. The photodetector outputs an electric signal corresponding to the light amount of the received fluorescent light

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentEP2634562B1Fluorescence sensor

Publication Date: 2020.07.08 TERUMO KK

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AI summary

A fluorescence sensor 10 includes a detection substrate section 20, on a first principal plane 21 of which a concave portion 23 having a bottom surface 22 parallel to the first principal plane 21 is present and, on a side surface 24 of the concave portion 23 of which a PD element 13 configured to receive fluorescent light F and output a detection signal is formed, an LED element 12 disposed on the bottom surface 22 of the concave portion 23 of the detection substrate section 20 and configured to generate excitation light E, and an indicator layer 16 disposed on an inside of the concave portion 23 on the LED element 12 and configured to generate the fluorescent light F corresponding to the excitation light E and an analyte amount.