Variable Polarization Attenuator for Lidar Eye Safety
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Solution Overview
Problem
Lidar systems using visible and near infrared lasers pose an eye hazard when stationary on the ground or at low altitudes and airspeeds, as the high beam intensity can expose ground crew and observers to risk, while reduced intensity may compromise system performance.
Innovation Solution
A laser transmitting system with a controllable intensity adjusting mechanism, such as a variable polarization attenuator, is used to automatically reduce the laser beam intensity based on safety criteria like altitude, presence of personnel, and aircraft speed, ensuring eye safety without compromising system performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high laser beam intensity is used, then system performance is maintained, but eye safety is compromised when stationary on ground or at low altitudes
Solution Approach 1:
The patent applies dynamics by making the laser intensity adjustable rather than fixed. The system dynamically changes the laser beam intensity based on operational conditions (altitude, motion state) to maintain high intensity for system performance when safe, and reduce intensity to prevent eye hazards when conditions require it. This is achieved through controllable attenuators or variable gain amplifiers that respond to feedback from sensors detecting altitude and motion parameters.
Solution Approach 2:
The patent changes the intensity parameter of the laser beam based on operational conditions. By monitoring altitude and motion state parameters, the system adjusts the laser intensity parameter dynamically - maintaining high intensity for optimal system performance during flight, and reducing intensity to safe levels when stationary on ground or at low altitudes to eliminate eye hazard risks.
2Object-affected harmful factors
If laser intensity is reduced to ensure eye safety, then harmful factors are eliminated, but system performance is compromised
Solution Approach 1:
The system dynamically adjusts laser intensity based on real-time operational conditions rather than using a fixed low intensity setting. When conditions indicate safety (during flight, at adequate altitude or speed), the system increases intensity to maintain performance. When conditions indicate hazard (stationary on ground, low altitude, low speed), the system reduces intensity to ensure eye safety. This dynamic response resolves the contradiction by making intensity conditional rather than fixed.
Solution Approach 2:
The patent implements feedback control by using sensors to monitor operational parameters (altitude, motion state) and using this information to automatically adjust laser intensity. The feedback loop ensures that intensity is optimized for system performance when safe, and reduced to protect eye safety when conditions require it, eliminating the need to permanently compromise performance.
3Object-affected harmful factors
If automatic intensity control is implemented, then safety criteria are satisfied, but device complexity increases
Solution Approach 1:
The patent applies multi-functionality by using the existing motion sensors and altitude detection systems (designed for navigation and operation) to also control laser safety. The same sensors that detect aircraft position and motion are repurposed to trigger intensity adjustments, eliminating the need for separate safety sensing systems and reducing overall device complexity.
Solution Approach 2:
The system performs self-service by automatically monitoring its own operational conditions and adjusting laser intensity without external intervention. The embedded control system uses onboard sensors to autonomously determine when intensity should be increased or decreased, making the safety control function self-regulating and reducing the need for complex external safety systems.
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
The system effectively attenuates the laser beam to safe levels when hazards are present, protecting ground personnel and maintaining system effectiveness by adjusting intensity dynamically in response to changing conditions.
Implementation Method 1
The adjustable polarization component is configured to rotate a polarization state of the laser beam between two polarization states
Implementation Method 2
The exit polarizer has a transmission axis that is parallel to a polarization direction of the laser beam when the adjustable polarization component is in a first configuration and perpendicular to the polarization direction of the laser beam when the adjustable polarization component is in a second configuration
Data Source
AI summary
A laser transmitting system includes a laser source configured to transmit a laser beam at an original transmit intensity. The system also includes a laser intensity adjusting mechanism positioned in the path of the transmitted laser beam. The laser intensity adjusting mechanism is controllable to reduce the intensity of the laser beam from the original transmit intensity. The system also includes a controller coupled to the laser intensity adjusting mechanism. The controller is configured to automatically control the laser intensity adjusting mechanism based upon a safety criteria. Methods of controlling a laser transmitting system are also provided.