Light Curtain Optical Unit Using DOE Laser Spot Alignment
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Solution Overview
Problem
Conventional light curtains for industrial safety have high fabrication costs due to the need for distinct emitter and receiver optical units, and existing modular transceiver bar configurations are not compatible with laser alignment techniques, leading to increased costs when additional laser modules are required.
Innovation Solution
A light curtain system using identical optical units with a single laser module per stick, employing an optical processing element that generates a defined radiation pattern for alignment, such as a micro-structured Diffractive Optical Element (DOE), allowing for accurate alignment without additional laser modules, and combining this with additional optical elements like lenses or waveguides for beam expansion and alignment features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If distinct emitter and receiver optical units are used, then alignment accuracy is maintained, but fabrication costs increase
Solution Approach 1:
The patent divides the alignment function into two parts: a laser module that emits the alignment beam and an optical processing element (such as a DOE - Diffractive Optical Element) that shapes the beam into a defined pattern. This segmentation allows the receiver unit to use a simple photodetector array rather than complex alignment optics, reducing fabrication costs while maintaining alignment accuracy through the structured light pattern.
Solution Approach 2:
The patent changes the parameter of the alignment beam by using an optical processing element to transform a simple laser beam into a defined radiation pattern (e.g., multiple spots, lines, or specific geometric shapes). This parameter change enables the receiver to detect alignment status through pattern recognition rather than requiring precise optical alignment, thereby reducing manufacturing complexity and costs.
2Ease of manufacture
If modular transceiver bar configuration is used, then fabrication costs are reduced, but compatibility with laser alignment techniques is lost
Solution Approach 1:
The patent makes the modular transceiver bar configuration compatible with laser alignment techniques by designing the receiver unit to perform dual functions: receiving the safety light curtain beams and detecting the laser alignment pattern. The optical processing element in the receiver can process both types of optical signals, providing universality that maintains fabrication cost benefits while restoring compatibility with laser alignment methods.
3Adaptability or versatility
If two laser modules are provided for each transceiver bar, then alignment compatibility is achieved, but fabrication costs increase
Solution Approach 1:
The patent extracts the laser module from the receiver unit and places it only in the transmitter bar, while the receiver uses an optical processing element to handle alignment detection. This extraction eliminates the need for two laser modules per bar configuration, reducing fabrication costs by removing redundant components while maintaining alignment compatibility through the optical processing element's ability to detect the laser pattern.
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 enables cost-effective and precise alignment of light curtain components, reducing fabrication costs and maintaining alignment accuracy, while allowing for flexible system configurations and easy assembly.
Implementation Method 1
an optical processing element for generating a defined radiation pattern from the radiation which is emitted by an alignment radiation source
Data Source
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AI summary
The present invention relates to light curtains, in particular safety light curtains, for monitoring a protective field. Furthermore, the present invention relates to optical units which are part of such a light curtain. An optical unit (100) for an alignment system of a light curtain monitoring a protective field comprises an optical processing element (102) for generating a defined radiation pattern from the radiation emitted by an alignment radiation source, and at least one additional optical functional element (106, 107,128) being formed integrally with said optical processing element.