Inverted Optical Particle Size Measuring Device
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Solution Overview
Problem
Conventional particle size measuring devices face challenges in achieving a balance between compact design, large measurement intervals, operational stability, ease of use, and effective stray light management, often resulting in complex structures and limited scattering angle ranges due to optical and design constraints.
Innovation Solution
A particle size measuring device with an inclined measuring cell and detector arrangement, allowing for a compact design that covers a wide measurement range by decoupling scattering angles around 90° and reducing stray light entry, without the need for moving parts or complex optical adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the distance between the measuring cell and the detector is increased to cover a larger particle size interval, then the measurable particle size range is improved, but the device size and optical path length increase
Solution Approach 1:
The patent inverts the conventional optical arrangement by placing the Fourier lens downstream of the measuring cell rather than upstream. This reverse configuration allows the scattering angle range to be decoupled from the focal length constraint, enabling a compact device design while maintaining a large measurable particle size interval from 0.1 µm to 3.5 mm.
2Adaptability or versatility
If the focal length of the Fourier lens is increased to expand the measurable particle size interval, then the measurement range is improved, but the device becomes less stable and more complex
Solution Approach 1:
By inverting the optical configuration and positioning the Fourier lens downstream, the patent achieves a compact focal length while maintaining the ability to measure across a wide particle size range. This inversion resolves the instability issue associated with long focal lengths while preserving measurement versatility.
Solution Approach 2:
The patent introduces a movable measuring cell that can be positioned at different locations along the optical path. This dynamic positioning capability allows the device to adjust the effective scattering angle range without changing the focal length, thereby maintaining stability while achieving versatile measurement capabilities.
3Adaptability or versatility
If the measuring cell is made movable to change the measurement interval, then the adaptability is improved, but the device complexity and stray light management become more difficult
Solution Approach 1:
The inverted optical configuration with the Fourier lens downstream simplifies the optical path geometry, making it easier to manage stray light and design the housing structure compared to conventional upstream lens arrangements, even with a movable measuring cell.
Solution Approach 2:
The patent extracts the beam expansion function from the upstream position and relocates it to the downstream position with the Fourier lens. This separation allows the measuring cell to move independently for interval adjustment while the optical path remains simpler and more manageable.
4Device complexity
If a conventional parallel beam configuration is used, then the optical path is simpler, but the measurable particle size interval is limited by the detector diameter and focal length
Solution Approach 1:
By inverting the optical configuration, the patent maintains relative optical path simplicity while fundamentally changing the relationship between focal length and measurable particle size interval. The reverse Fourier transform arrangement allows the detector to capture a broader range of scattering angles, expanding the measurable particle size interval without proportionally increasing complexity.
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 enables a compact, stable, and user-friendly device that can accurately measure a broad range of particle sizes with improved stray light management and reduced complexity, enhancing operational stability and measurement precision.
Implementation Method 1
the primary light beam, which together with the scattering center and the center of the forward sensor defines the main optical axis, is scattered by the particles of the sample material to be examined
Implementation Method 2
the diffraction pattern thus generated on the sample particles is detected by a detector device
Data Source
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AI summary
The invention relates to a particle size measuring device in which the particle size distribution of sample particles in a measuring cell is determined on the basis of the diffraction pattern of a primary light beam, which comprises: a light source for generating a primary light beam which defines an optical principal axis, a measuring cell with an entrance window and an exit window, a detector device for detecting the diffraction pattern generated by the sample material, wherein the measuring cell is oriented obliquely to the optical principal axis in the measuring plane.