VCSEL Array Safety Laser Scanner Design
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Solution Overview
Problem
Current safety laser scanners used in safety technology are limited by their size and cost due to the need for a single high-power edge emitter laser diode, which results in large construction volumes and potential false shutdowns from interference, and do not effectively minimize design hindrances in operational environments.
Innovation Solution
The use of at least four VCSEL laser diodes with lower peak power, arranged to distribute transmission energy and operate with high pulse rates, allowing for smaller design, reduced edge artifacts, and adaptable transmission power to enhance reliability and reduce false shutdowns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a single high-power edge emitter laser diode is used to generate transmitted light pulses, then sufficient power for reliable object detection is achieved, but the construction volume increases and design is hindered
Solution Approach 1:
The patent divides the single high-power laser diode into multiple low-power VCSEL laser diodes (at least four) arranged in an array. Each VCSEL emits a light beam that is directed onto the deflection unit. This segmentation allows the system to achieve sufficient total transmission power through multiple lower-power sources while reducing the construction volume compared to a single high-power edge emitter laser diode.
2Reliability
If a single high-power edge emitter laser diode is used, then reliable detection of objects with various surface materials is achieved, but the device size increases
Solution Approach 1:
The patent uses multiple VCSEL laser diodes instead of a single edge emitter laser diode. This segmentation provides spatial diversity in the transmission beam paths, improving the probability of detecting objects with different surface materials and reflectivity characteristics. The multiple beams cover a broader area and provide redundant detection paths, enhancing reliability while keeping the device compact.
Solution Approach 2:
The patent changes the operational parameters by using VCSELs that operate at different wavelengths or with different pulse characteristics compared to traditional edge emitter laser diodes. This allows adaptation to various object surface materials and improves detection reliability across different target types while maintaining a compact form factor.
3Measurement precision
If high pulse rates are used with VCSEL laser diodes, then statistical evaluation improves detection accuracy, but the system complexity increases
Solution Approach 1:
The patent implements a feedback mechanism where the control unit receives signals from the evaluation unit about detected objects and their positions. Based on this feedback, the control unit adjusts the pulsing patterns of individual VCSELs and coordinates with the deflection unit to optimize detection. This feedback loop enables statistical evaluation at high pulse rates while maintaining manageable system complexity through intelligent control algorithms.
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 enables a more compact and reliable safety laser scanner with reduced edge artifacts and increased machine availability by distributing transmission energy and using high pulse rates for statistical evaluation, while maintaining eye safety and adaptability to varying object reflectivity.
Implementation Method 1
a light transmission unit (12) consisting of at least four VCSEL laser diodes (18-1 to 18-4) with which pulsed transmission light beams (16) are emitted into a monitored area (22)
Implementation Method 2
a light receiver (34) with upstream receiving optics (32) for receiving remission light (17) that is remitted by an object in the monitored area (22). The light receiver (34) converts the reflected light into received signals
Implementation Method 3
the position value of the reflection in the monitoring area is determined in an evaluation unit from the angle signal and the time between the emission and reception of a light pulse
Data Source
Figure 1~2
Figure 3a~3d
Figure 4
AI summary
The scanner has a light receiver (34) for receiving signals from transmission light impulses emitted by an object in a monitoring area (22). An angle providing unit (28) outputs a signal that represents instantaneous angle position of a deflection unit, and an evaluating unit (38) determines position of reflection in the area based on the signal and time between transmission and reception of light pulses. A failsafe output (40) outputs a safety switching signal when the evaluating unit detects impermissible access in a preset protection field within the area.