Flat Bar Geometry for Particle Size Analyzer Thin Film Control
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Solution Overview
Problem
Existing devices for measuring light scattered by high concentrations of particles or macromolecules in colloidal media face issues such as surface damage, manufacturing difficulties, residual reflectivity, and inability to perform measurements under flow due to small contact surfaces and delicate convex finger construction.
Innovation Solution
A device with a new geometry featuring a flat surface on a bar that maintains parallelism with a dioptric element, allowing for measurements under flow, simplified manufacturing, and reduced risk of surface damage, using a transparent bar with an angled end to minimize reflection and diffusion disturbances, and incorporating optical components like lenses and CCD sensors for precise analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a convex bar with polished surface is used to delimit the thin film, then the analysis zone can be made very thin, but the surface of the bar and/or prism is damaged after several uses leading to measurement artefacts
Solution Approach 1:
The invention inverts the traditional convex bar geometry by using a flat bar surface. Instead of polishing a convex surface to create a thin film, the flat bar works in conjunction with a flat prism surface to define the thin film gap. This inversion eliminates the scratching problem while maintaining the ability to create a thin, well-defined analysis zone.
Solution Approach 2:
The invention segments the optical path by introducing a flat bar that creates a distinct separation between the incident light path and the scattered light detection path. The flat bar surface and flat prism surface work together to define a controlled thin film region, allowing the system to maintain measurement precision without compromising surface integrity.
2Object-generated harmful factors
If a convex bar is used to limit reflected light, then parasitic intensity is reduced, but residual reflectivity from the black bar still interferes with measurement
Solution Approach 1:
The invention extracts the light-blocking function from the bar itself by using the flat bar primarily to define the geometric boundaries of the thin film. The parallelism between the flat bar surface and flat prism surface creates a controlled optical path where reflected light is naturally directed away from the detection path, eliminating the need for black coating and its associated residual reflectivity problems.
3Manufacturing precision
If a convex finger with small contact surface is used, then a specific analysis zone is created, but measurement under flow cannot be performed without disturbing the measurement
Solution Approach 1:
The invention inverts the approach to flow measurement by using a flat bar geometry that creates a larger contact area with the prism surface. This flat configuration, combined with the parallel surfaces, allows the system to accommodate flow conditions while maintaining a well-defined thin film analysis zone, unlike the convex geometry which is sensitive to flow disturbances.
4Ease of manufacture
If a flat bar surface is used instead of convex, then manufacturing is simplified and surface damage is prevented, but the ability to create a thin analysis zone must be maintained
Solution Approach 1:
The invention inverts the traditional approach by using flat surfaces for both the bar and prism, eliminating the need for difficult convex polishing operations. The thin film gap is controlled through the precise positioning and parallelism of these flat surfaces, which can be manufactured more easily while maintaining the required precision through assembly control rather than complex surface geometry.
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
Enables accurate and repeatable measurements of light scattered intensity without surface damage, allows for flow measurements without disturbing the analysis, and provides precise control over the thin film's thickness and parallelism, enhancing measurement reliability and reducing artifacts.
Implementation Method 1
a monochromatic light source, a convergent optical system focusing said source on the thin film to be analyzed and comprising a dioptric element
Implementation Method 2
at least one photosensitive detector reacting to the light scattered or backscattered by the thin film
Implementation Method 3
one of the faces of which constitutes a first wall delimiting the thin film... another second wall is formed by a flat surface at the end of a bar
Data Source
Figure 1
Figure 2a
Figure 2b~3b
AI summary
The present invention relates to a device for measuring the intensity of light scattered by a thin film of a colloidal medium, comprising: a monochromatic light source; a convergent optical system focusing said light source onto the thin film to be analyzed and comprising a dioptric element (7), one of the faces of which constitutes a first wall delimiting the thin film; at least one photosensitive detector reacting to the light scattered or backscattered by the thin film; and means for processing the signal coming from the photodetector. According to the device, the other, second wall is formed by a plane surface (3) on the end of a rod (2).