Light Curtain Material Identification via NIR Spectroscopy
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Solution Overview
Problem
Conventional light curtains are limited in providing detailed qualitative information about objects entering their monitoring area, mainly allowing for point-shaped detection and rough external shape identification, with difficulty in material differentiation.
Innovation Solution
A light curtain system utilizing near-infrared radiation and a wavelength-dispersive device, such as a blazed grating, to generate a two-dimensional image with wavelength-resolved information, enabling the differentiation of hydrocarbons and organic compounds through spectroscopic examination, and subsequent material composition analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If conventional light curtains are used for object detection, then the detection of objects entering a monitoring area is achieved, but detailed qualitative information about material composition cannot be obtained
Solution Approach 1:
The patent combines light curtain detection technology with near-infrared spectroscopy into a single integrated system. The light curtain provides object detection and positioning, while the NIR spectroscopy module simultaneously analyzes material composition by measuring reflectance spectra. This merging allows the system to obtain both spatial information and material characterization without requiring separate detection systems.
Solution Approach 2:
The detection device is designed to perform multiple functions: object detection, positioning, and material composition analysis. By integrating a camera for spatial detection with a spectrometer for spectral analysis, the system universally handles both security monitoring and material identification tasks within a single device framework.
2Measurement precision
If spectroscopic analysis is added to light curtain systems for material identification, then material composition detection is improved, but device complexity increases
Solution Approach 1:
The patent extends the detection capability from the spatial domain to the spectral domain. While conventional light curtains only provide spatial information about object location, the integrated NIR spectroscopy adds a spectral dimension by measuring reflectance at multiple wavelengths. This dimensional extension enables material differentiation based on spectral signatures without fundamentally redesigning the spatial detection architecture.
Solution Approach 2:
The patent introduces an intermediary spectral analysis module that bridges object detection and material identification. The spectrometer acts as an intermediary device that receives light reflected from objects detected by the light curtain and converts it into spectral information. This intermediary component enables material characterization while maintaining the independence and simplicity of the original light curtain system.
3Loss of information
If near-infrared radiation is used for spectroscopic examination, then organic material identification is enhanced, but energy consumption increases
Solution Approach 1:
The patent changes the wavelength parameter of the illumination light to the near-infrared range (750-1000 nm). This parameter change targets the vibrational and rotational absorption bands characteristic of organic materials, enabling precise identification of plastics, liquids, and tissue. The NIR parameter range is specifically selected to maximize information content about organic compounds while using commercially available LED light sources that are energy-efficient.
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
Facilitates the identification of material composition and classification of objects, allowing for the generation of output signals for selection or operation halt, enhancing the functionality of light barriers by combining detection with spectroscopic analysis.
Implementation Method 1
an essentially elongated or one-dimensional image is initially generated, which can be wavelength-dispersively fanned out, in particular diffracted, in a direction other than that of the image
Implementation Method 2
In spectroscopy the wavelength-dependent absorption and emission signals of materials are investigated and analyzed
Implementation Method 3
the radiation striking one or several recipients is analyzed, wherein for example intensity differences of the radiation striking the recipients are determined
Data Source
AI summary
Systems and methods are disclosed for the detection and identification of objects, wherein an illumination device emits polychromatic light in the infrared range, creating a light curtain, or an essentially two-dimensional area of light in the X and Z axis. The light from the light curtain and light reflected or transmitted by an object in the light curtain is imaged, via aperture-imaging optics, onto an aperture that is in the optical path and behind the aperture-imaging optics. The aperture is an elongated opening extending along the Z axis. A wavelength-dispersive device, such as a grating, diffracts light admitted by the aperture wavelength-dispersively in a diffraction direction along the Y axis. An image sensor detects the diffraction image and generates image signals which are analyzed to identify the materials comprising the object. An output signal may be generated in response to the material identified.