Laser Amplifier Dynamic Range Control
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Solution Overview
Problem
Existing pulsed laser systems for material processing, such as printing rolls, face limitations in dynamic range, leading to degraded print quality due to pulse shape smearing and timing inconsistencies, which restricts the range of print resolutions and ink transfer, necessitating multiple lasers for different resolutions.
Innovation Solution
A laser processing apparatus comprising a seed laser, an amplifier, and a controller that synchronizes the seed pump, amplifier pump, and scanner to operate the amplifier as both an optical attenuator and amplifier across different power ranges, enabling improved dynamic range by maintaining consistent pulse shapes and timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If pulse power is varied in prior art pulsed lasers, then dynamic range is improved, but pulse shape smears and pulse timing is delayed
Solution Approach 1:
The laser system is segmented into a seed laser and a separate amplifier stage. The seed laser generates consistent low-power pulses with precise timing and shape, while the amplifier provides power boosting. This segmentation allows the pulse generation and power amplification to be independent, resolving the contradiction between dynamic range and pulse shape consistency.
Solution Approach 2:
The seed laser performs preliminary action by generating precisely-shaped pulses before they enter the amplifier. By establishing the correct pulse shape and timing characteristics in advance, the system ensures that even when amplified to high power levels, the pulses maintain their intended form without smearing or timing delays.
2Power
If long pulsed fibre lasers are used, then average power is increased, but dynamic range is restricted and print resolution is limited
Solution Approach 1:
The system uses dynamic control of the amplifier pump to adjust the amplification factor in real-time based on the required output power. This allows the laser to adapt between high average power for coarse features and low average power for fine features, achieving a dynamic range of at least 30dB while maintaining long pulse durations for high average power operation.
3Device complexity
If prior art lasers with dynamic range less than 20dB are used, then device complexity is reduced, but print quality degrades and multiple lasers are needed
Solution Approach 1:
The laser system is designed as a universal platform that can handle both coarse and fine featured items across a dynamic range of at least 30dB. The seed laser-amplifier architecture with coordinated control enables a single device to perform multiple functions (high power coarse processing and low power fine processing) that would otherwise require separate laser systems, improving print quality while managing complexity through integrated control.
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 solution achieves a dynamic range of at least 30dB, allowing for both high-resolution and low-resolution processing without degrading print quality, enabling the laser to efficiently handle 'coarse' and 'fine' featured items within the same operating range, significantly exceeding the typical 20dB range of conventional systems.
Implementation Method 1
controller controls the amplifier pump to cause the amplifier to act as an optical attenuator when the optical radiation is in a first power range, and as an optical amplifier when the output power is in a second power range
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
Apparatus for laser processing a material (8) with optical radiation (T), which apparatus comprises a seed laser (1) pumped by a seed pump (2), an amplifier (3) pumped by an amplifier pump (4), a controller (5), and a scanner (6), wherein the controller (5) controls the seed pump (2), the amplifier pump (4) and the scanner (6) in synchronism such that optical pulses (10) emitted by the seed laser (1) are propagated through the amplifier (3) and directed to the material (8) by the scanner (6), the apparatus being characterized in that controller (5) controls the amplifier pump (4) to cause the amplifier (3) to act as an optical attenuator when the optical radiation (7) is in a first power range, and as an optical amplifier when the output power is in a second power range.