Scanning Laser Projector Safety Shutoff via Peak Angle Monitoring
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Solution Overview
Problem
Scanning laser projectors face challenges in ensuring safe operation within predetermined safety limits, as existing systems lack effective mechanisms to dynamically adjust scan angles and laser power in real-time to prevent exceeding safety thresholds, potentially leading to unsafe conditions.
Innovation Solution
The implementation of a scanning laser projector system that includes a microelectromechanical system (MEMS) device with a scanning mirror, a light detector, and a safety shutoff component, which measures peak scan angles and laser power, and compares these metrics to thresholds to dynamically adjust the scan angles and laser power, ensuring operation within safety limits by shutting off the light source if thresholds are exceeded.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the laser beam power and scan angle are increased to improve projection quality and coverage area, then the projection performance is improved, but the safety risk increases and may exceed safety classification limits
Solution Approach 1:
The patent implements a feedback control system that continuously monitors the actual scan angle and laser power output, compares these values against safety thresholds, and dynamically adjusts the laser operation to maintain safe operating conditions while optimizing projection performance when thresholds permit
Solution Approach 2:
The system dynamically adjusts laser power and scan angle parameters in real-time based on monitored conditions, transitioning between different operating states (normal operation, reduced power, shutdown) to maintain safety while maximizing performance when conditions allow
2Reliability
If the safety monitoring system continuously measures and compares scan angles and laser power to thresholds, then the safety reliability is improved, but the device complexity increases
Solution Approach 1:
The control system performs multiple functions using integrated components: it monitors scan angle via sensors, measures laser power output, compares both parameters against safety thresholds, and controls laser operation all through a unified control circuit that manages safety and performance optimization
3Reliability
If the system dynamically adjusts laser power and scan angle in real-time to maintain safety limits, then the safety compliance is improved, but the productivity and continuous operation capability deteriorate due to potential shutdowns
Solution Approach 1:
The system dynamically transitions between operating states based on real-time conditions: maintaining full power when safe, reducing power when approaching thresholds, and shutting down only when necessary, thereby maximizing continuous operation while ensuring safety compliance
Solution Approach 2:
The continuous feedback loop monitors operating conditions and immediately adjusts laser parameters to maintain safe operation, preventing shutdowns by keeping operations within safety margins while still utilizing maximum permissible power and scan angles
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 effectively prevents the scanning laser projector from operating beyond safety limits by dynamically adjusting scan angles and laser power, ensuring safe operation and compliance with safety classifications like class 2 as defined in IEC 60825-1, thereby preventing potential hazards.
Implementation Method 1
a scanner that is associated with the laser light source and has one or more mirrors capable of scanning the laser beam along X-Y coordinates
Implementation Method 2
a photodetector to measure a power of the laser beam
Data Source
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AI summary
A scanning projector (100) includes a MEMS device (160) with a scanning mirror (162) that sweeps a light beam in two dimensions. A laser limit comparison circuit (140) determines a metric from measured peak scan angles and measured light output. The metric is compared to a threshold and a light source is shut down when the metric exceeds the threshold.