Laser Output Control Device Using Pulse Width Switching
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Solution Overview
Problem
Conventional laser output control devices are complex and costly due to the need for high-speed power sensors and simulated value compensation, leading to instability and increased expenses.
Innovation Solution
A laser output control device that switches between peak value control and average value control based on the pulse width of the laser light, using a single power sensor to generate current command values for the laser oscillator, thereby simplifying the device configuration and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-speed power sensors are used to detect laser peak output, then measurement precision is improved, but device cost increases and stability deteriorates due to noise and disturbance
Solution Approach 1:
The patent uses a low-speed power sensor to detect the average output, then creates a simulated copy of the peak output waveform through calculation based on the detected average value and known pulse width. This simulated waveform serves as a stable reference for feedback control without requiring expensive high-speed sensors that are prone to noise interference.
Solution Approach 2:
The patent introduces a simulated output waveform as an intermediary between the actual laser output and the feedback control system. This simulated waveform, generated through calculation rather than direct high-speed detection, mediates the control process and eliminates the need for unstable high-speed power sensors while maintaining control precision.
2Adaptability or versatility
If high-speed power sensors with extended time constants are used for average value control, then low frequency response is improved, but device cost increases due to larger capacitances
Solution Approach 1:
The patent replaces the physical extension of sensor time constants using large capacitors with a computational approach. By calculating the simulated peak waveform from the detected average waveform and pulse width information, the system achieves low-frequency response capability without requiring physically large capacitance components, thereby reducing device complexity and cost.
3Measurement precision
If simulated value compensation is implemented to compensate for amplifier delays, then control precision is improved, but device complexity increases
Solution Approach 1:
The patent makes the control system self-sufficient by using the detected average output waveform and known pulse width parameters to automatically generate the simulated peak waveform through calculation. This self-generated simulated signal provides the necessary compensation for amplifier delays without requiring external complex compensation circuits or additional sensors, thereby improving precision while maintaining simplicity.
Data Source
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AI summary
A laser output control device controlling a laser oscillator, includes a switching section switching, on the basis of the size of a pulse width of a laser output command used when generating an output waveform of a laser light, a current command value used for controlling output of the laser light to either one of peak value control in which a peak value of a pulse shape is used, and average value control in which an average value of a pulse shape is used; a peak value command generating section generating a current command value using the peak value of the pulse shape when performing peak value control; and an average value command generating section generating a current command value using the average value of the pulse shape when performing average value control, and an output value of the laser light measured by one measuring section, is input to the peak value command generating section and the average value command generating section, and the current command value is generated such that the output value of the laser light becomes a value that corresponds to the laser output command.