Dual-View Particle Sizing with Homogeneous Illumination

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Solution Overview

Problem

Existing particle measuring devices face limitations in achieving a high dynamic measuring range with accurate particle size and shape determination, particularly due to issues with image display and evaluation, especially when dealing with transparent or photosensitive particles, and require significant adjustment efforts and may cause optical distortions and chemical changes.

Innovation Solution

A device with a common illumination system for both measurement areas, using a beam splitter to ensure homogeneous illumination and separate light radiation into parts with the same spectral intensity, and employing pulsed illumination to adapt exposure to camera devices' magnification, reducing adjustment complexity and optical distortions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If two light sources illuminate two measurement zones with different intensities to achieve optimal illumination, then the measurement accuracy is improved, but image evaluation is disturbed due to overexposure and saturated pixels

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidimage evaluation quality
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent changes the illumination parameter from different intensities to equal intensities for both measurement zones. By illuminating both zones with the same light intensity, the patent prevents overexposure and saturated pixels in the lower magnification zone, thereby maintaining image evaluation quality while still achieving accurate particle measurement through the use of two camera devices with different magnifications.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If crossed beam paths are used to record two measurement zones with different magnifications, then the dynamic measuring range is expanded, but optical distortion occurs due to non-perpendicular incidence on glass surfaces

Engineering Contradiction:
Improvedynamic measuring rangeVSAvoidoptical distortion
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent uses a single beam path that serves multiple functions: it illuminates both measurement zones sequentially and allows for consistent optical conditions. By using the same beam path for both measurement zones rather than crossed beam paths, the patent eliminates optical distortion caused by non-perpendicular incidence on glass surfaces while maintaining the expanded dynamic measuring range through sequential illumination of zones with different magnifications.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Loss of information

If stronger illumination is used in one measurement area to improve image quality, then the image clarity is improved, but chemical changes occur in photosensitive particles

Engineering Contradiction:
Improveimage clarityVSAvoidchemical changes in particles
Core Design Contradiction:
Loss of informationVSObject-affected harmful factors

Solution Approach 1:

The patent uses periodic or pulsed illumination to illuminate the measurement zones. By controlling the illumination in time-separated pulses rather than continuous strong illumination, the patent achieves sufficient image clarity while minimizing the total energy exposure to photosensitive particles, thereby preventing chemical changes in the measured objects.

Inventive Principle:
Principle #19Periodic action

4Adaptability or versatility

If two independent beam paths are used to illuminate and record measurement zones, then the measurement flexibility is improved, but calibration effort increases significantly

Engineering Contradiction:
Improvemeasurement flexibilityVSAvoidcalibration time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent merges the illumination function into a single system that serves both measurement zones. By using one illumination device that can illuminate both zones with equal intensity through a single beam path, the patent eliminates the need for separate calibration of multiple independent beam paths, significantly reducing calibration effort while maintaining measurement flexibility through sequential zone illumination.

Inventive Principle:
Principle #5Merging (Combining)

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

The solution enables high-accuracy particle size and shape determination with a wide dynamic measuring range, minimizing adjustment effort and preventing image evaluation issues, while ensuring homogeneous illumination and reducing the risk of chemical changes or optical distortions.

Implementation Method 1

an optical element is provided for dividing the light radiation emanating from the measuring zone into two radiation parts

Methodology Applied
Scientific EffectBeam splitting: Reflection

Implementation Method 2

imaging optics for imaging the measurement areas; The object plane is imaged by the imaging optics in at least two preferably non-parallel image planes

Methodology Applied
Scientific EffectImage formation by optics: Lens

Implementation Method 3

an illumination device for illuminating the measuring zone; both measurement areas are illuminated together, with both measurement areas being illuminated with the same intensity

Methodology Applied
Scientific EffectLight emission: Light

Data Source

PatentEP3207356B1Apparatus and method for determining the particle size and/or the particle shape of particles in a particle stream
Publication Date: 2020.06.03 RETABCH TECH
  • EP3207356B1 patent drawingFigure 1~2
  • EP3207356B1 patent drawingFigure 3~4
  • EP3207356B1 patent drawingFigure 5~6

AI summary

The invention relates to an apparatus (1) for determining the particle size and/or the particle shape and/or the optical properties, such as transparency, of particles (2) in a particle stream (3). Said apparatus comprises: a feed device (4) for feeding the particles (2) to a measurement zone (5), the particles (2) flowing through the measurement zone (5); at least one lighting device (6) for lighting the measurement zone (5); at least two camera devices (7, 8), each recording a measurement region (9, 10) of the measurement zone (5) associated with one of the camera devices (7, 8), a first camera device (7) recording a first, preferably larger, measurement region (10) with a first, preferably lesser, magnification, and a second camera device (8) recording a second, preferably smaller, measurement region (9) with a second, preferably stronger, magnification; an imaging optics (11) for imaging the measurement regions (9, 10); and an evaluation device for determining the particle size and/or the particle shape from the images of the measuring regions (9, 10), the imaging optics (11) having at least one optical element (14) on which and/or by which the light radiation emitted by the measuring zone (5) is split up into at least two radiation parts. The lighting device (6) is designed such that the first measurement region (10) and the second measurement region (9) are always lighted jointly, the first measurement region (10) being lighted with the same intensity as the second measurement region (9).