Focused Illumination System for Optical Sorting
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Solution Overview
Problem
Existing optical sorting machines face challenges in achieving optimal photonic effectiveness and spatial stability due to issues with illumination confinement, leading to inefficiencies in signal detection and spectral stability, particularly when dealing with objects of varying thickness and transparent materials.
Innovation Solution
The machine employs a focused illumination system where the illumination region is confined within the detection region, ensuring that the focused illumination region is contained within the detection region over the entire inspection width, using incoherent wide-spectrum sources and a scanning mechanism to maintain alignment and reduce illumination power, thereby enhancing spatial and spectral stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If diffuse illumination sources with large angles are used to illuminate objects of varying thickness, then all detection lines in the detection plane can be analyzed, but the proportion of illuminated region in the field of sensors is small at each height, reducing photonic effectiveness
Solution Approach 1:
The patent applies local quality by making the illumination angular distribution non-uniform across different spatial locations. Specifically, the illumination source is designed to provide different angular distributions at different positions: larger angles for regions requiring depth penetration and smaller angles for regions where precise spatial confinement is needed. This localized optimization of illumination angles allows the system to maintain photonic effectiveness while accommodating objects of varying thickness.
2Loss of energy
If movable coaxial illumination is used to improve photonic effectiveness by illuminating only the vicinity of the pixel, then energy is saved, but the illumination overflows with a spot diameter much larger than the pixel and very little signal is returned from transparent objects
Solution Approach 1:
The patent employs parameter changes by dynamically adjusting the angular distribution of illumination based on the detection requirements. The system modifies the illumination parameters (angles, intensity distribution) as a function of position and object properties. This allows the illumination to be concentrated where needed while maintaining appropriate angular spread for different material types, thereby improving both energy efficiency and detection quality simultaneously.
3Loss of energy
If fiber-optic assemblies are used to achieve proper confinement of illumination at several millimeters, then illumination is confined, but they are unusable in optical sorting due to limited working distance
Solution Approach 1:
The patent introduces an intermediary optical system that acts as a mediator between the illumination source and the detection plane. This intermediary optical train includes relay lenses and beam shaping elements that transfer and condition the illumination over the required distance. The intermediary system maintains illumination confinement while extending the working distance, effectively decoupling the confinement requirement from the distance limitation.
4Adaptability or versatility
If incoherent wide-spectrum sources are used for illumination, then the spectrum covers the primary ranges of optical sorting, but achieving optimal photonic effectiveness and spatial stability is difficult due to illumination confinement issues
Solution Approach 1:
The patent applies dynamics by making the illumination system adaptable and adjustable rather than fixed. The angular distribution, intensity, and spatial configuration of the illumination can be dynamically modified to match the specific detection requirements. This dynamic capability allows the system to maintain spatial stability and photonic effectiveness while preserving the broad spectral coverage of incoherent wide-spectrum sources.
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 reduces illumination requirements, improves spatial stability, and optimizes spectral analysis, allowing for precise chemical composition and color-based sorting with reduced interference and improved detection quality across the conveyor belt.
Implementation Method 1
emission of non-coherent and wide-spectrum radiation... the technology that is in question and that is implemented is based on the emission of non-coherent and wide-spectrum radiation. As a result, the machines and systems taken into account in the state of the art use all of the tungsten-halogen-type thermal illumination sources
Implementation Method 2
detection means (9) making it possible to scan periodically each point of the illumination line (8) and that continuously receives the radiation that is reflected by an elementary measurement region
Implementation Method 3
means for application and focusing of inspection radiation... focused illumination region in the form of a transverse strip... the focused illumination region is contained in the detection region
Data Source
AI summary
A machine for automatically inspecting a flow (F) of individual objects (2) on a conveying plane (3) includes at least one illumination station (4) and at least one detection station (4′) below which the flow (F) of objects to be inspected passes. The at least one illumination station (4) has means (6) for applying and focusing inspecting beams (R) defining a transverse focused illuminated region (ZEF) The at least one detection station (4′) has a means (9) defining a detection region (ZD) in the form of a transverse strip of size (L) as well as means (9,1) for capturing and transmitting the signal contained in a pixel (10) scanning the detection region (ZD). The focused illuminated region (ZEF) fits along the entire width (L) of the detection region (ZD) within this detection region.