Illumination Laser Power Switching for Low-NOHD Eye Safety
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Solution Overview
Problem
Existing methods for reducing minimum eye safety distances during laser illumination in urban environments are limited by high NOHD values, leading to safety restrictions and reduced illumination quality, especially when using non-eye-safe wavelengths, which are expensive and inefficient.
Innovation Solution
The laser radiation device operates the illumination laser in multiple modes, adjusts beam path overlap, and dynamically controls laser power and repetition frequency to maintain low NOHD values while ensuring compliance with exposure limits, using separate apertures and distance-dependent power adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the illumination laser power is increased to improve illumination quality and object recognition, then the illumination quality improves, but the NOHD value increases causing safety restrictions
Solution Approach 1:
The illumination laser power is dynamically adjusted based on the operational mode. In active object observation mode, the power is increased to P2 for improved illumination quality. In fine tracking mode, the power is reduced to P1 to minimize NOHD. This dynamic adaptation allows the system to optimize illumination quality only when necessary while maintaining safety during fine tracking operations.
Solution Approach 2:
The illumination laser operates in periodic pulses rather than continuous emission. The laser emits illumination radiation in controlled pulses during active object observation, then reduces or stops emission during fine tracking. This periodic operation allows high power illumination when needed while minimizing exposure and NOHD during other phases.
2Object-affected harmful factors
If the illumination laser power is limited to minimum values to reduce NOHD, then safety improves, but the illumination quality and object recognition quality deteriorate
Solution Approach 1:
The system dynamically switches between two power levels (P1 and P2) based on the operational requirements. During fine tracking, low power P1 maintains safety with acceptable NOHD. During active object observation, high power P2 provides sufficient illumination quality. This dynamic switching resolves the contradiction by adapting power to the specific task.
3Productivity
If emitter aperture size is reduced to improve laser characteristics, then laser performance improves, but the intensity near the aperture increases causing higher NOHD values
Solution Approach 1:
The aperture system dynamically adjusts its effective size or configuration based on the operational mode. During fine tracking, the aperture configuration minimizes intensity concentration to reduce NOHD. During active object observation, the aperture allows higher intensity for improved illumination. This dynamic aperture control resolves the contradiction between laser performance and safety.
Data Source
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AI summary
A method is presented for operating a laser radiation device (10) which comprises an illumination laser (14) and an active laser (13), wherein the illumination laser (14) is operated in a first mode of operation of the laser radiation device (10), in which the active laser (13) does not emit any active laser radiation (20), in such a way that the illumination laser radiation (22) of the illumination laser exhibits a first illumination laser radiant flux. The method is distinguished in that the illumination laser (14) is operated in a second mode of operation of the laser radiation device (10), in which the active laser (13) emits active laser radiation (20), in such a way that the illumination laser radiation (22) of the illumination laser exhibits a second illumination laser radiant flux which is greater than the first illumination laser radiant flux.