Laser Emitter Shutdown Circuit for Fast Optical Fault Response
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Solution Overview
Problem
Existing LIDAR systems face challenges in rapidly responding to unsafe conditions, such as a damaged or detached optical element, which can lead to unsafe laser light emission due to the slow reaction time of software-based controllers.
Innovation Solution
A hardware-based shutdown circuit that utilizes a photodiode and a conductive path to detect unsafe conditions, preventing current flow to the laser emitter by detecting the absence of pulses in the signal, thereby ensuring rapid shutdown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a software-based controller is used to detect unsafe conditions, then the system can detect damaged or detached optical elements, but the reaction time is too slow to prevent unsafe laser light emission
Solution Approach 1:
The patent replaces the software-based control system with a hardware-based shutdown circuit that directly monitors optical elements and immediately interrupts laser emission when damage or detachment is detected, eliminating software processing delays and achieving instantaneous response
Solution Approach 2:
The patent introduces an intermediary hardware circuit between the optical elements and the laser emitter that continuously monitors the optical path and independently triggers shutdown without waiting for software detection, providing a dedicated fast-response channel for safety critical events
2Speed
If a hardware-based shutdown circuit is implemented, then the shutdown speed and reliability are improved, but the device complexity increases
Solution Approach 1:
The patent extracts the safety monitoring function from the main control system into a separate, dedicated hardware shutdown circuit with its own independent sensors and control logic, allowing the main system to remain simple while the safety subsystem provides rapid response
Solution Approach 2:
The patent divides the safety system into distinct functional segments: optical element sensors, signal processing circuitry, and laser shutdown control, each performing a specific function that can be independently optimized and maintained
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 hardware-based shutdown circuit provides faster and more reliable laser emitter shutdown, preventing unsafe laser emissions by quickly detecting and responding to optical element damage or detachment.
Implementation Method 1
a photodiode configured to output a first signal based on light emitted by the laser emitter and reflected from the optical element
Data Source
AI summary
A shutdown circuit may include a filter, for receiving a laser trigger signal for a laser emitter, that is configured to output a filtered signal. The shutdown circuit may include a logic gate configured to receive the filtered signal and at least one of a first signal based on a signal from a photodiode or a second signal based on a signal from a conductive path. The shutdown circuit may include a flip-flop configured to receive an output of the logic gate and to output an enablement signal that is based on the output of the logic gate, and a driver circuit for a switch configured to control current flow to the laser emitter. The driver circuit may be configured to receive the enablement signal and the laser trigger signal and to output the laser trigger signal based on whether the enablement signal is a first or a second voltage.