Dielectric Multilayer Coating for Fluorescence Detection
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Solution Overview
Problem
Conventional fluorescence measurement methods face challenges in detecting small fluorescence signals due to autofluorescence from substrates, which results in poor sensitivity and signal-to-noise ratio, especially when using high-polymer materials that emit autofluorescence when irradiated with excitation light.
Innovation Solution
A fluorescence measurement apparatus with a wavelength selection means, comprising a dielectric multilayer coating on the substrate's surface that reflects excitation light and transmits fluorescence, allowing the fluorescence to be detected by a light receiving unit beneath the substrate, while minimizing autofluorescence interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If high-polymer materials are used as substrate, then ease of manufacture and moldability are improved, but autofluorescence increases causing poor signal-to-noise ratio
Solution Approach 1:
The substrate is divided into two functional layers: a high-polymer base layer providing ease of manufacture and molding, and a separate dielectric multilayer coating applied on top to provide optical functionality. This segmentation allows each layer to optimize its specific function without compromising the other.
Solution Approach 2:
The substrate becomes a composite structure combining high-polymer material with a dielectric multilayer coating. The dielectric layers (alternating high and low refractive index materials) form a composite optical structure that reflects excitation light while transmitting fluorescence, solving the autofluorescence problem while maintaining the benefits of high-polymer substrates.
2Measurement precision
If excitation light irradiates the sample, then fluorescence signal is generated, but autofluorescence from substrate is also generated causing background noise
Solution Approach 1:
The dielectric multilayer coating is applied locally on the substrate surface in the region where the sample is placed. This localized treatment ensures that excitation light is reflected and fluorescence is transmitted only at the measurement location, while maintaining the original substrate properties elsewhere.
Solution Approach 2:
The optical parameters (refractive index) are changed by applying dielectric layers with different refractive indices. The alternating high and low refractive index layers create constructive interference for reflecting excitation light and constructive interference for transmitting fluorescence wavelengths, effectively separating the excitation and emission light paths.
3Illumination intensity
If conventional substrate materials are used, then transparency to ultraviolet light is maintained, but autofluorescence occurs when irradiated with excitation light
Solution Approach 1:
The dielectric multilayer coating acts as an intermediary between the excitation light source and the high-polymer substrate. It reflects the excitation light before it can penetrate deeply into the substrate and generate autofluorescence, while still allowing the substrate to maintain its ultraviolet transparency for other applications.
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 approach significantly reduces autofluorescence noise, enabling highly sensitive detection of small fluorescence signals by reflecting excitation light and amplifying the fluorescence signal through multiple reflections, thereby improving the signal-to-noise ratio.
Implementation Method 1
a wavelength selection means, which reflects the excitation light and transmits the fluorescence
Implementation Method 2
a wavelength selection means comprising a dielectric multilayer coating on the substrate's surface
Implementation Method 3
they tend to emit autofluorescence when irradiated with excitation light
Data Source
AI summary
On a substrate 41 holding a sample to be detected, a dielectric multilayer 42 is disposed which reflects excitation light e1 supplied from above the substrate 41 and transmits fluorescence f1 emitted from the sample, and the excitation light e1 is reflected at the dielectric multilayer 42 while the transmitted fluorescence f1 is detected by a light receiving unit 44, thereby providing a fluorescence measurement apparatus which can resolve a problem of reduction in detection sensitivity due to autofluorescence from the substrate or leakage of the excitation light from a light receiving filter, and which can detect the sample with high sensitivity.