Microprocessor Laser Safety Circuit with Independent Hardware Limits
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Solution Overview
Problem
Existing safety circuits for laser-based medical devices are complex and costly, making them unsuitable for consumer use without professional supervision, and there is a need for effective interlock mechanisms to prevent improper operation and ensure safe usage.
Innovation Solution
A combination of hardware and software safety features, including current limit, pulsewidth limit, and PRF limit circuits, along with temperature monitoring and software-based safety checks, that operate independently to prevent laser emissions in case of faults, ensuring safe operation by overriding control signals and entering fault modes when malfunctions are detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complicated mechanical and electromechanical interlocks are used to ensure safety, then safety reliability is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces complicated mechanical and electromechanical interlocks with a microprocessor-based control system that uses software logic and electronic sensors to implement safety interlocks. This substitution eliminates complex mechanical linkages while maintaining safety functionality through digital control mechanisms that monitor operational parameters and enforce safety constraints programmatically.
Solution Approach 2:
The invention changes the operational parameters of the laser device through software control, allowing dynamic adjustment of laser firing conditions based on monitored parameters such as tip temperature, applicator position, and operational state. This enables sophisticated safety logic to be implemented through parameter monitoring and conditional control rather than fixed mechanical interlocks.
2Reliability
If complicated mechanical and electromechanical interlocks are used to ensure safety, then safety reliability is improved, but cost increases
Solution Approach 1:
The patent replaces complicated mechanical and electromechanical interlocks with a microprocessor-based control system that uses software logic and electronic sensors to implement safety interlocks. This substitution eliminates complex mechanical linkages while maintaining safety functionality through digital control mechanisms that monitor operational parameters and enforce safety constraints programmatically.
3Reliability
If independent safety features are implemented to detect malfunctions, then safety reliability is improved, but device complexity increases
Solution Approach 1:
The microprocessor-based control system performs multiple functions including normal laser control, safety monitoring, parameter logging, and fault detection within a single integrated platform. This multi-functionality allows independent safety features to be implemented without proportionally increasing overall device complexity, as the central controller handles diverse tasks through software modules rather than requiring separate dedicated hardware for each function.
Data Source
AI summary
A safety and interlock circuit for use with devices which could cause injury if an error condition causes improper operation. A control program executing on a processor monitors a variety of device conditions, including pulse over-duration threshold, diode over-current threshold, pulse lock-out duration, temperature threshold, and pulse repetition frequency limit, and prevents the laser from firing if an error condition is detected. In addition, the error conditions are logged in a persistent memory to facilitate subsequent diagnosis and correction.