Supercontinuum Laser Sorting Device for Multi-Wavelength Product Analysis

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Solution Overview

Problem

Current laser sorting apparatuses face challenges due to the limited availability and high cost of specific laser wavelengths, complexity in combining multiple lasers, interference issues with irregular surfaces, and the need for specialized electronics and optics, which restrict their adaptability and accuracy in sorting diverse products.

Innovation Solution

The use of a supercontinuum light source generated in a photonic crystal fiber, which provides a broadband spectrum allowing for flexible selection of wavelengths and improved coherence, coupled with an endlessly single mode fiber for guiding light, enabling efficient and accurate sorting across a wide spectral range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple laser sources are used to provide specific wavelengths for sorting, then the sorting capability for different product types is improved, but the device complexity and cost increase significantly

Engineering Contradiction:
Improvesorting capability for different product typesVSAvoidcomplexity of optical system
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent employs a single supercontinuum laser source that can generate multiple wavelengths across a broad spectrum (400-2000 nm), replacing the need for multiple discrete laser sources. This universal light source can be tuned to different wavelengths to sort various product types including plastics, food, and pharmaceuticals, thereby achieving multi-functionality while reducing device complexity

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

Solution Approach 2:

The invention utilizes an acousto-optic tunable filter (AOTF) to dynamically change the wavelength parameter of the light beam. By adjusting the RF frequency applied to the AOTF, the system can select different wavelengths from the supercontinuum source without physical reconfiguration, enabling adaptable sorting for different products while maintaining a simple optical path

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If multiple laser beams are combined into one single beam, then the sorting system can handle multiple wavelengths, but the beam combination becomes extremely difficult due to different cross-section shapes

Engineering Contradiction:
Improvemulti-wavelength capabilityVSAvoidease of beam combination
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent extracts the wavelength selection function from the beam combination process by using a single supercontinuum source with an AOTF. Instead of combining multiple laser beams with different cross-sections, the system generates a broad spectrum from one source and extracts the desired wavelength through the AOTF, eliminating the beam combination problem entirely

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The AOTF serves as an intermediary device between the supercontinuum source and the product. It selects the required wavelength from the broad spectrum and delivers it as a single, well-collimated beam, mediating the transition from broadband light to monochromatic sorting light without requiring complex beam combination optics

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If a fixed set of laser sources is used, then the system is optimized for specific product types, but the adaptability to sort other types of products is limited

Engineering Contradiction:
Improvesorting accuracy for specific productsVSAvoidflexibility for different product types
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The system transitions from a static configuration of fixed laser wavelengths to a dynamic, tunable wavelength selection using an AOTF. The RF frequency applied to the AOTF can be dynamically adjusted to select different wavelengths in real-time, allowing the same hardware to be optimized for different product types including plastics, food, and pharmaceuticals without physical reconfiguration

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The supercontinuum laser source provides a universal broadband spectrum (400-2000 nm) that can cover the absorption characteristics of various materials. By combining this universal source with programmable wavelength selection, the system achieves multi-functionality for sorting diverse product types while maintaining high precision through wavelength optimization for each specific application

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

4Adaptability or versatility

If broadband sources like HID lamps are used, then a wide spectral range is available, but the spatial coherence and brightness are low resulting in poor sorting performance

Engineering Contradiction:
Improvespectral range coverageVSAvoidspatial coherence and brightness
Core Design Contradiction:
Adaptability or versatilityVSIllumination intensity

Solution Approach 1:

The patent uses a composite approach by combining a supercontinuum laser source (providing high brightness and spatial coherence) with an AOTF (providing broadband spectral coverage). This composite system achieves both the wide spectral range of broadband sources and the high illumination intensity and coherence of laser sources, overcoming the limitations of using either type alone

Inventive Principle:
Principle #40Composite materials

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 solution enhances sorting accuracy and flexibility by providing a high spectral density and single-mode guidance, reducing the need for multiple lasers and specialized optics, and allowing for the sorting of products based on various parameters like oil and water content.

Implementation Method 1

The use of a supercontinuum light source generated in a photonic crystal fiber, which provides a broadband spectrum allowing for flexible selection of wavelengths and improved coherence

Methodology Applied
Scientific EffectSupercontinuum generation:

Implementation Method 2

The use of a supercontinuum light source generated in a photonic crystal fiber

Methodology Applied
Scientific EffectPhotonic crystal fiber guidance: Photonic Crystal

Implementation Method 3

coupled with an endlessly single mode fiber for guiding light, enabling efficient and accurate sorting across a wide spectral range

Methodology Applied
Scientific EffectOptical waveguide guidance: Waveguide (optics)

Implementation Method 4

at least one light beam is directed towards this product by means of a moving mirror, whereby the product moves in a particular direction through a detection zone, so that said light beam, which preferably moves transversely across the path of the product, is at least partially scattered and/or reflected by said product

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 5

said light beam, which preferably moves transversely across the path of the product, is at least partially scattered and/or reflected by said product

Methodology Applied
Scientific EffectLight scattering: Scattering

Implementation Method 6

The scattered and/or the reflected light is detected by at least one detector

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 7

The scattered and/or the reflected light is detected by at least one detector in order to characterize and to sort the product

Methodology Applied
Scientific EffectLight detection: Photoelectric Effect

Data Source

PatentEP2200758B1Sorting device with a supercontinuum radiation source and according method
Publication Date: 2014.01.08 TOMRA SORTING NV
  • EP2200758B1 patent drawingFigure 1
  • EP2200758B1 patent drawingFigure 2~3
  • EP2200758B1 patent drawingFigure 4~5

AI summary

The invention relates to a system comprising a broadband optical light source and a sorting device and more specifically to laser sorting devices. The object of the present invention is to provide a system comprising a sorting device with a light-source offering all wavelengths for the sorting process. This is solved by using an all fiber supercontinuum light source.