Laser Beam Deflection Optics for Consistent Ultrashort Pulse Spacing
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Solution Overview
Problem
Ultrashort pulse lasers with high average powers face challenges in maintaining consistent pulse spacing during material processing, leading to inhomogeneous heating and material property issues due to varying movement speeds and inertia in movement systems, causing laser pulses to overlap and impact processing quality.
Innovation Solution
An apparatus comprising a pulse-precise deflector unit and transformation optics arrangement that deflects and transforms the laser beam to ensure precise spatial and angular adjustments, allowing for synchronized movement with the feed apparatus to maintain consistent pulse spacing and prevent overlap, using acousto-optic deflectors and Fourier optics to achieve high diffraction efficiency and beam shaping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the laser pulse frequency is fixed or variable only to a limited extent, then the laser system operates stably, but the spacing of laser pulses along the feed trajectory varies when movement speed changes, causing inhomogeneous heating
Solution Approach 1:
The patent applies dynamics by making the laser pulse frequency variable rather than fixed. The control unit dynamically adjusts the pulse frequency in real-time based on the actual movement speed of the feed apparatus, allowing the system to adapt to speed variations and maintain consistent pulse spacing along the feed trajectory despite changes in movement conditions
Solution Approach 2:
The patent implements feedback by using the control unit to monitor the actual movement speed of the feed apparatus and adjust the laser pulse frequency accordingly. This closed-loop control ensures that pulse spacing remains consistent by continuously comparing the desired spacing with the actual spacing and making real-time corrections to the pulse frequency
2Adaptability or versatility
If the feed apparatus moves with varying speed or sudden direction changes, then the processing can adapt to complex trajectories, but the laser pulses spatially overlap in the material, causing inhomogeneous heating
Solution Approach 1:
The system dynamically adjusts the laser pulse frequency in real-time based on the instantaneous movement speed of the feed apparatus. When the feed apparatus slows down during direction changes or complex trajectories, the pulse frequency is reduced proportionally, preventing pulse overlap and maintaining uniform energy distribution and heating homogeneity throughout the processed material
Solution Approach 2:
The patent changes the temporal parameter of the laser system by varying the pulse frequency in response to movement speed changes. This parameter adjustment ensures that the spatial spacing between pulses remains constant along the feed trajectory, regardless of variations in feed speed or trajectory complexity, thereby preventing inhomogeneous heating
3Productivity
If high average power is used, then the processing efficiency increases, but the pulse frequency must be extended to prevent pulse overlap, requiring extended system technology
Solution Approach 1:
The control unit serves multiple functions: it monitors the movement speed of the feed apparatus, calculates the required pulse frequency to maintain consistent spacing, and adjusts the laser pulse frequency accordingly. This multi-functional approach allows the system to handle high average powers and complex trajectories without requiring separate dedicated systems for each function, thereby reducing overall system complexity while maintaining productivity
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 enables precise control over laser beam deflection and shaping, ensuring consistent energy distribution and improved material processing quality by compensating for feed rate variations and inertia-related issues, maintaining high repetition frequency and energy stability.
Implementation Method 1
a pulse-precise deflector unit (3) configured to deflect the laser beam (20) in at least one direction perpendicular to a beam propagation direction
Implementation Method 2
a transformation optics arrangement (4) having at least two components which is arranged downstream of the pulse-precise deflector unit (3) and is configured to transform a spatial deflection and/or an angular deflection of the laser beam (20) into the angular deflection and/or the spatial deflection
Implementation Method 3
a processing optical unit (9) arranged downstream of the transformation optics arrangement (4) and configured to guide the laser beam (20) into an image-side focal plane of the processing optical unit (9)
Data Source
AI summary
An apparatus for influencing a laser beam from an ultrashort pulse laser includes a pulse-precise deflector unit configured to deflect the laser beam in at least one direction perpendicular to a beam propagation direction, a transformation optics arrangement having at least two components arranged downstream of the pulse-precise deflector unit. The transformation optics arrangement is configured to transform a spatial deflection and/or an angular deflection of the laser beam into the angular deflection and/or the spatial deflection, and/or transform the spatial deflection and the angular deflection inversely, by using a space-to-angle transformation and/or an angle-to-space transformation. The apparatus further includes a processing optical unit arranged downstream of the transformation optics arrangement and configured to guide the laser beam into an image-side focal plane of the processing optical unit.