Metal-Coated Particle Imaging for Fluid Contamination Detection
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Solution Overview
Problem
Existing techniques for characterizing particles in fluid samples, particularly small particles, are insufficient due to challenges in distinguishing between particles and surface roughness, and they are sensitive to background noise, leading to inaccurate detection.
Innovation Solution
A method involving depositing a metallic film on a substrate, bringing a fluid sample into contact, removing the fluid to leave particles, and applying a metallic layer to each particle with a gap, then illuminating with electromagnetic rays to enhance scattering and absorption for accurate imaging and detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dark-field imaging with strong illumination sources is used to detect small particles, then detection sensitivity is improved, but sensitivity to background noise from surface roughness increases
Solution Approach 1:
A metallic layer is introduced as an intermediary between the substrate surface and the particle. This metallic layer serves as a mediator that enhances the optical scattering signal from particles while providing a uniform reference background, thereby improving particle detection sensitivity without amplifying noise from substrate roughness.
Solution Approach 2:
The optical properties of the detection system are changed by introducing a metallic layer with specific optical characteristics. This layer modifies the scattering and absorption parameters, creating enhanced contrast between particles and the background surface, allowing sensitive detection while maintaining noise rejection.
2Illumination intensity
If bright-field imaging is used to detect particles through light absorption, then the background signal is enhanced, but detection of particles with small absorption is difficult
Solution Approach 1:
The metallic layer acts as an intermediary that converts the detection mechanism from direct particle absorption to particle-induced scattering modifications. This intermediary layer amplifies the optical interaction, making particles with small absorption cross-sections detectable through their scattering signature.
Solution Approach 2:
The metallic layer introduces optical contrast through scattering effects that manifest as intensity variations in the imaging system. This creates detectable signal variations for particles that would otherwise be invisible due to their small absorption, effectively changing the optical signature from absorption-based to scattering-based detection.
3Measurement precision
If strong illumination sources are used to detect small particles, then detection capability is improved, but discrimination between particles and surface roughness becomes challenging
Solution Approach 1:
The metallic layer provides uniform local optical properties across the substrate surface, creating a consistent reference background. Particles introduce localized perturbations to this uniform field, creating distinct contrast that enables easy discrimination between particles and the underlying surface structure.
Solution Approach 2:
The metallic layer serves as a mediator that decouples the detection signal from the substrate surface properties. By placing this intermediate layer, the system detects particle-induced perturbations in the metallic layer's optical response rather than direct interactions with the substrate, thereby eliminating confusion from surface roughness.
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
Enhances the detection of particle characteristics by amplifying scattering and absorption, allowing for more precise identification of particles and contamination levels in fluid samples.
Implementation Method 1
Optical scattering cross section is proportional to the sixth power of the particle radius. Therefore, detection of small particles (e.g. particles with radii less than 50-nm-diameter) requires strong illumination sources and sensitive photodiodes.
Implementation Method 2
In another approach bright-field imaging based on optical absorption and scattering is used to detect particles deposited on a surface
Data Source
Figure 1(a)~1(h)
Figure 2(a)~2(h)
Figure 3(a)~3(h)
AI summary
According to the present invention there is provided a method for determining a characteristic of particles in a fluid sample and/or for determining a contamination characteristic of the fluid sample, the method comprising the steps of, (a) depositing a metallic film on a surface of a substrate to provide a smooth, metallic surface on said substrate; (b) bringing the fluid sample into contact with said metallic surface of the substrate; (c) removing said fluid sample which was brought into contact with said metallic surface, from said metallic surface, so that only particles which were in said fluid sample remain on the metallic surface of the substrate; (d) depositing a layer of metal on said metallic surface and said particles which remained on said metallic surface of the substrate, so that each of said particles is provided with a respective metallic layer and an area of the said metallic surface which is without particles is provided with a metallic layer, wherein, for each particle there is a gap between the metallic layer on the particle and the metallic layer on said metallic surface; (e) illuminating said layers of metal on said particles and metallic surface with electromagnetic rays, so that said electromagnetic rays are scattered by layers of metal on said particles to produce respectively scattered electromagnetic rays; or illuminating said layers of metal on said particles and metallic surface with electromagnetic rays, so that at least a portion of said electromagnetic rays are absorbed by layers of metal on said particles and another portion of said electromagnetic rays are reflected by the metallic surface on the substrate to produce reflected electromagnetic rays; (f) receiving the scattered electromagnetic rays at an array of photodiodes; or receiving the said reflected electromagnetic rays at an array of photodiodes; (g) forming an image which comprises pixels, wherein each pixel in the image corresponds to a respective photodiode in said array, wherein the brightness of each pixel in said image corresponds to the intensity of the electromagnetic rays which photodiode corresponding to that pixel received; (h) processing said formed image to determine a characteristic of said particles and/or processing said formed image to determine a contamination characteristic of the fluid sample.