Laser Beam Shaping for Variable Top-Hat Material Processing
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Solution Overview
Problem
Laser beams with top-hat intensity profiles are not consistently maintained along the beam direction due to wave nature laws, leading to less advantageous intensity profiles between specific positions, which complicates precise material processing with short pulses.
Innovation Solution
Utilizing optical elements to modulate the laser beam's wavefront, allowing the projection of a top-hat intensity profile onto a workpiece at specific positions by varying the beam diameter while maintaining the profile, either by displacing the workpiece or manipulating the beam with diffractive or refractive elements, ensuring consistent energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a top-hat intensity profile is generated at a specific position in the laser beam, then good processing results are achieved at that position, but the intensity profile changes to less advantageous profiles at other positions along the beam direction
Solution Approach 1:
The patent employs dynamic focusing by moving the focal plane of the laser beam along the beam direction during material processing. This allows the top-hat intensity profile to be maintained at different positions along the workpiece, enabling consistent processing quality throughout the depth of the material while adapting to varying processing requirements at different depths
Solution Approach 2:
The patent changes the focal position parameter dynamically during processing. By adjusting the focus position to coincide with different positions having top-hat intensity profiles along the beam direction, the system maintains optimal energy distribution for precise erosion at each processing depth, resolving the contradiction between position-specific precision and overall profile stability
2Manufacturing precision
If the workpiece is displaced in the laser beam to jump between positions with top-hat intensity profile, then processing can be performed at optimal positions, but the process becomes elaborate and slow due to relatively large masses moved
Solution Approach 1:
Instead of moving the workpiece to achieve optimal processing positions, the patent inverts the approach by moving the focal plane of the laser beam along the beam direction. This maintains the workpiece in a stationary position while dynamically adjusting the focus to coincide with different top-hat intensity profile positions, thereby achieving precise processing without the time penalty of moving large workpiece masses
Solution Approach 2:
The patent replaces the mechanical displacement of the workpiece with optical focusing mechanisms. By using beam focusing and focal plane adjustment instead of physical workpiece movement, the system achieves the same processing objective (positioning at top-hat intensity profiles) with much faster response time and without the inertia constraints of moving large masses
3Adaptability or versatility
If beam diameter is varied to perform rough and fine processing, then processing versatility is improved, but maintaining consistent top-hat intensity profile becomes more difficult
Solution Approach 1:
The patent dynamically adjusts the focal plane position to maintain top-hat intensity profiles at different beam diameters. By coordinating focus position changes with beam diameter variations, the system enables versatile processing (rough and fine) while maintaining consistent energy distribution characteristics through real-time optical parameter adjustment
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
Enables efficient and reproducible material processing with varying beam diameters, allowing for both rough and fine processing without significant changes in power density, improving processing efficiency and precision.
Implementation Method 1
at least one beam-shaping diffractive or refractive second optical element (2) for modulating a wavefront of the laser beam in such a way that, after focusing of the beam by the third optical element (3), there is a top-hat beam profile in a plurality of planes in the convergent beam
Implementation Method 2
at least one beam-shaping diffractive or refractive second optical element (2) for modulating a wavefront of the laser beam
Implementation Method 3
after focusing of the beam by the third element, there is a top-hat beam profile in a plurality of planes in the convergent beam
Data Source
AI summary
A device for projecting a laser beam onto a workpiece includes at least one first optical element, at least one second optical element, and at least one third optical element. The at least one first optical element is configured to project the laser beam onto the at least one second, in particular diffractive, optical element. The at least one second optical element is configured to convert an intensity profile of the laser beam. The at least one third optical element is configured to project the laser beam onto the workpiece. The device is configured such that a diameter of the laser beam on the workpiece can be varied while maintaining the intensity profile with a stationary workpiece.