Laser Scanner Phase Synchronization for Precision Structuring
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Solution Overview
Problem
Current laser processing systems face challenges in achieving high absolute precision for surface structuring, particularly in directing individual laser pulses to predefined positions on target materials, which is essential for complex surface structures like gravure forms.
Innovation Solution
The method involves synchronizing the movement of a laser scanner with laser pulses using a phase-locked scanner control signal, adjusting the phase to ensure accurate positioning, and using a master oscillator power amplifier (MOPA) arrangement with a passive mode-locked seed laser to enhance precision. Additionally, incorporating a mechanical axis and an optical sensor with a pinhole allows for precise alignment and compensation of misalignments, enabling the production of large structures with high accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If complicated means for adjusting laser source position are used to achieve high precision, then positioning accuracy is improved, but device complexity increases
Solution Approach 1:
The patent substitutes complex mechanical adjustment systems with an electronic control system. Instead of physically adjusting the laser source position through complex mechanical means, the system uses a photodetector to detect pulse positions and a control unit to adjust the scanner control signal phase, achieving the same positioning accuracy with significantly reduced mechanical complexity.
Solution Approach 2:
The patent introduces a photodetector as an intermediary element that mediates between the laser pulses and the control system. The photodetector converts optical position information into electrical signals that the control unit can process, enabling precise positioning control without direct mechanical intervention in the laser path.
2Manufacturing precision
If continuous wave laser sources with scan error correction are used, then scan precision is improved, but the system does not address pulsed laser processing requirements
Solution Approach 1:
The patent adapts continuous wave scan correction concepts to pulsed laser systems by changing the key parameter from continuous light intensity control to discrete pulse timing control. The system uses phase adjustment of the scanner control signal relative to pulsed laser emission, enabling precise positioning for pulsed lasers while maintaining the effectiveness of scan error correction principles.
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 approach significantly improves the absolute precision of laser processing, allowing for the generation of complex surface structures with many individual dots on large surfaces, reducing adjustment time while maintaining high precision without complex phase control of the laser pulse train.
Implementation Method 1
a laser source capable of emitting a beam of laser pulses for processing a target
Implementation Method 2
a laser scanner which is configured to move the beam of laser pulses over the target to be processed
Data Source
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Figure 6~6c
AI summary
A method for adjusting a laser processing apparatus, whereby the laser processing apparatus comprises a laser source capable of emitting a beam of laser pulses for processing a target, and a laser scanner which is configured to move the beam of laser pulses over the target to be processed, and whereby a movement of the laser scanner is synchronized with respect to the laser pulses, wherein for synchronisation a phase of a scanner control signal which controls the movement of the laser scanner is locked to the laser pulses or a laser pulse signal, is characterized in that the phase of the scanner control signal is adjusted such that an emitted laser pulse hits the target to be processed in a desired position.