Laser Machining Mask Assembly for Beam Size and Diffraction Control
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Solution Overview
Problem
Existing laser machining systems face issues with controlling the beam size and steepness of laser beams on projection focal planes, leading to wider openings and narrower bottoms in drilled holes or grooves, and diffraction patterns damaging the workpiece surface.
Innovation Solution
A laser machining mask assembly comprising an initial mask and a first correction mask, where the correction mask includes mapping regions that control the beam size by adjusting the laser beam's path, using amplitude or phase mask types to enhance beam control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional laser machining mask is used, then the laser beam can be projected onto the workpiece, but the beam size cannot be effectively controlled and diffraction patterns damage the workpiece surface
Solution Approach 1:
The patent divides the single mask into two separate masks: an initial mask that defines the basic pattern and a correction mask that compensates for diffraction effects. This segmentation allows independent optimization of each mask's function, enabling precise beam size control while eliminating diffraction pattern damage to the workpiece surface.
Solution Approach 2:
The correction mask is designed in advance based on the diffraction characteristics of the initial mask. By pre-calculating and pre-compensating for the diffraction patterns that will be generated, the system eliminates harmful effects before they occur during the actual machining process, rather than attempting to correct them afterward.
2Manufacturing precision
If the laser beam is projected through a single mask, then the machining process can be performed, but the steepness of the laser beam profile is insufficient leading to poor hole quality
Solution Approach 1:
The patent segments the beam control function into two stages: the initial mask provides the basic beam shaping, while the correction mask refines the beam profile to achieve high steepness. This two-stage approach enables precise control of the laser beam profile that cannot be achieved with a single mask, resulting in holes with superior steepness and quality.
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 assembly effectively reduces beam size and diffraction patterns, resulting in higher steepness and precise laser drilling/scribing with reduced surface damage, suitable for laser drilling, scribing, and patterning processes.
Implementation Method 1
the diffraction pattern of the irradiance profile of the laser beam 94 after the laser beam 94 propagating through the unmasked region 95 of the laser machining mask 90 and the projection lens 92 can be observed
Implementation Method 2
The initial mask 3 is amplitude mask type. The initial mask 3 comprises an initial masked region 31 where the initial masking layer 33 is formed and an initial unmasked region 30 where the initial masking layer 33 is not formed
Implementation Method 3
Any of the one or more first mapping region is amplitude mask type or phase mask type
Data Source
AI summary
A laser-machining-mask-assembly for projection laser machining comprises an initial mask and a correction mask. The laser-machining-mask-assembly and a projection lens are sequentially arranged on a propagation path of a laser beam generated by a machining laser apparatus along a propagation direction of the laser beam. The correction mask is arranged between the initial mask and the projection lens or the initial mask is arranged between the correction mask and the projection lens. The initial mask is amplitude-mask-type. The correction mask comprises a mapping region mapped from an unmasked region of the initial mask with a shape and an area identical to the unmasked region. The mapping region is amplitude-mask-type or phase-mask-type. A beam size of the laser beam projected on a projection focal plane after the laser beam propagating through the laser-machining-mask-assembly and the projection lens can be effectively controlled by using the correction mask.