Scanning Laser Devices with Multiple Range Emission Control Pulse Sets
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Solution Overview
Problem
LiDAR systems face challenges in achieving effective ranging while ensuring eye safety, particularly in reducing accessible radiation levels to prevent eye damage and comply with safety standards like IEC 60825.1, which requires additional safety measures for non-eye-safe laser devices.
Innovation Solution
The implementation of emission control pulse sets with varying energy levels to detect objects within specific safety ranges, where lower energy pulse sets are used initially to prevent higher energy pulses from being emitted when objects are close, thereby enhancing eye safety and reliability of detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If higher energy laser pulses are emitted to achieve effective sensing at long ranges, then detection range is improved, but eye safety is compromised due to increased accessible radiation levels
Solution Approach 1:
The system performs preliminary detection using lower energy pulses at multiple safety ranges before emitting higher energy ranging pulses. Emission control pulse sets are transmitted first to detect objects within defined safety ranges, and only if no objects are detected does the system proceed to emit higher energy pulses for extended ranging. This preliminary action prevents harmful high-energy emissions when objects are present in safety ranges.
Solution Approach 2:
The system dynamically changes the energy parameter of laser pulses based on detection requirements and safety conditions. Multiple emission control pulse sets with different energy levels are used for different safety ranges, and the system selectively transitions between these energy levels. Higher energy pulses are only emitted when safety conditions are met, thus optimizing both detection range and eye safety.
2Object-affected harmful factors
If multiple emission control pulse sets with different energy levels are implemented to ensure eye safety, then eye safety is improved, but device complexity increases
Solution Approach 1:
The emission control system is segmented into multiple discrete pulse sets, each associated with a specific safety range and energy level. The first emission control pulse set corresponds to a first safety range with first energy level, the second pulse set corresponds to a second safety range with second energy level, and so on. This segmentation allows independent control and optimization of each safety range without requiring complex integrated control logic.
Solution Approach 2:
The system uses periodic pulse sets with progressively increasing energy levels and corresponding safety ranges. Each pulse set is transmitted in a structured sequence, with the system periodically checking for objects at each safety range before proceeding to the next energy level. This periodic structure simplifies control by establishing a predictable, repeating pattern of emission and detection cycles.
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 allows for reliable object detection at extended ranges while maintaining eye safety by conditionally emitting higher energy pulses only when objects are not within defined safety ranges, improving both detection reliability and compliance with safety standards.
Implementation Method 1
a detector configured to receive reflections of the laser light pulses from the objects within the scan field. The received reflections of the laser light pulses may then be used to detect the objects and determine a distance to the objects (e.g., using time-of-flight (TOF) measurements)
Implementation Method 2
a detector configured to receive reflections of the laser light pulses from the objects within the scan field
Data Source
AI summary
The embodiments described herein provide systems and methods that can improve performance in scanning laser devices. Specifically, the systems and methods emit first emission control pulse sets that are used to detect when objects (e.g., persons) are within a relatively close first safety range. Then second emission control pulses to detect when objects are within a second safety range. Then, higher energy long-range pulse sets are conditionally emitted only when objects were not detected within the first and second safety ranges with the first and second emission control pulse sets. The use of first and second emission control pulse sets can provide for improved reliability of nearby object detections, while still meeting the energy limits needed for eye safety.