Multi-Wavelength Light Curtain for Transparent Object Detection
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Solution Overview
Problem
Conventional light curtain systems for high-flux power beams struggle to accurately distinguish between guard beam signals from different emitters, leading to false negatives when foreign objects, especially transparent or reflective ones, intrude into the beam path, due to overlapping light fields and lack of distinct wavelength differentiation.
Innovation Solution
The system employs a plurality of emitters and detectors with distinct emission wavelengths and characteristics, forming a light curtain with multiple sub-paths and using retro-reflectors to differentiate between guard beam signals, allowing for precise detection of obstacles by distinguishing between different wavelengths and absorptive properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If conventional light curtain systems use overlapping light fields from multiple emitters, then the coverage area is improved, but the ability to distinguish between guard beam signals from different emitters deteriorates
Solution Approach 1:
The patent assigns different wavelengths (colors) of light to different emitters within the light curtain system. Each emitter emits light at a distinct wavelength, allowing detectors to differentiate between signals from different emitters even when their light fields overlap in space. This resolves the contradiction by enabling both extensive coverage through multiple emitters and precise signal differentiation through wavelength discrimination.
Solution Approach 2:
The patent changes the physical parameter of light wavelength for each emitter to create distinguishable signals. By varying the wavelength parameter across different emitters, the system maintains clear signal identification despite spatial overlap of light fields, thus achieving both broad coverage and high measurement precision simultaneously.
2Device complexity
If the light curtain uses single wavelength detection, then the system simplicity is improved, but the detection accuracy for transparent and reflective objects deteriorates
Solution Approach 1:
The patent employs multiple wavelengths in the light curtain system to detect different types of objects. By using wavelengths that are absorbed differently by various materials, the system can detect transparent and reflective objects that would be invisible at a single wavelength. This multi-wavelength approach maintains reasonable system complexity while dramatically improving detection accuracy for challenging objects.
3Length of stationary object
If the light curtain emitters operate at high intensity, then the detection range is improved, but the false negative rate from signal overlap deteriorates
Solution Approach 1:
The patent uses different wavelengths for different emitters, allowing each emitter to operate at high intensity for extended detection range while the unique wavelength signature prevents signal confusion. The wavelength differentiation ensures that even high-intensity signals from multiple emitters can be reliably distinguished, maintaining low false negative rates despite increased detection range.
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 approach enhances the accuracy of obstacle detection, preventing false negatives by effectively distinguishing between guard beam signals and ensuring the high-flux power beam is safely interrupted when necessary, even in the presence of transparent or reflective objects.
Implementation Method 1
using retro-reflectors to differentiate between guard beam signals
Implementation Method 2
detectors with distinct emission wavelengths and characteristics, forming a light curtain with multiple sub-paths
Implementation Method 3
emitters and detectors with distinct emission wavelengths and characteristics
Data Source
Figure 1
Figure 2
Figure 3A~3C
AI summary
A system to detect obstacles includes a power beam transmission circuit, a power beam reception circuit arranged to receive a power beam from the power beam transmission circuit, an emitter module, and a detector module arranged to distinguish between a first characteristic and a second characteristic. The emitter module includes a first emitter arranged to emit a first signal having the first characteristic, the first signal emitted in proximity to the power beam, and a second emitter arranged to emit a second signal having the second characteristic, the second characteristic different from the first characteristic, the second signal emitted in proximity to the first signal. The detector module includes a first detector arranged to respond to the first signal emitted by the first emitter, wherein the detector module is arranged to determine when an obstacle is in or near a line-of-sight transmission path between the first emitter and the first detector.