Diffractive Ring Beam Optics for Deep Crack-Free Laser Cutting
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Solution Overview
Problem
Existing axicon lens-based Bessel beam optical apparatuses face challenges in precisely controlling cutting thickness and often cause micro-cracks due to their short depth of focus and inability to adjust beam intensity uniformly, leading to degraded processing quality.
Innovation Solution
A laser processing apparatus with a housing part, aperture part, multi-focal diffractive lens part, and multilayer focusing lens part, which forms a ring beam with uniform energy distribution and long depth of focus, allowing precise cutting without damaging surrounding areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If a large-angle axicon lens is installed to extend the depth of focus, then the depth of focus is improved, but the overall size of the module increases
Solution Approach 1:
The patent divides the optical system into multiple components: an axicon lens for generating a Bessel beam and a diffractive optical element (DOE) for extending the depth of focus. This segmentation allows each component to perform its specific function optimally without requiring a single large-angle axicon lens, thereby extending depth of focus while maintaining a compact module size.
Solution Approach 2:
The patent combines the axicon lens and diffractive optical element into a single integrated optical module. The axicon lens generates the Bessel beam while the DOE modifies the beam profile to extend the depth of focus. This merging of functions allows the system to achieve extended depth of focus without increasing the overall module size, as the components work together in a compact arrangement.
2Use of energy by moving object
If an axicon lens-based Bessel beam optical apparatus is used, then energy delivery to a narrow area is improved, but the ability to precisely control beam intensity deteriorates
Solution Approach 1:
The patent introduces a diffractive optical element (DOE) as an intermediary component between the axicon lens and the processing target. The DOE modifies the Bessel beam generated by the axicon lens, creating a structured light pattern that provides both high energy concentration and precise intensity control. This intermediary element enables independent optimization of energy delivery and intensity control.
Solution Approach 2:
The patent utilizes the diffractive optical element to change the spatial distribution parameters of the beam intensity. By designing the DOE with specific diffraction patterns, the system can control the intensity profile of the output beam independently from the energy concentration achieved by the axicon lens. This parameter control allows precise adjustment of beam intensity while maintaining effective energy delivery to the narrow processing area.
3Power
If an axicon lens-based Bessel beam optical apparatus is used, then nonlinear optical absorption is improved, but the creation of micro-cracks on the surface deteriorates processing quality
Solution Approach 1:
The patent applies local quality by using the diffractive optical element to create a structured light pattern with varying intensity distribution across the beam cross-section. This allows different regions of the processed material to receive appropriate energy levels: high intensity for effective cutting through nonlinear optical absorption, while controlled lower intensity regions prevent excessive heat accumulation that would cause micro-cracks. The local intensity modulation ensures precise energy delivery without damaging the surrounding areas.
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 apparatus achieves precise cutting through thick objects with a long depth of focus and uniform energy distribution, reducing the risk of micro-cracks and enabling miniaturization due to fewer components.
Implementation Method 1
a multi-focal diffractive lens part installed below the aperture part inside the housing part for bending the incident beam into multiple orders along the optical axis, simultaneously diffracting the deflected beams to form a circular beam (Ring Beam)
Implementation Method 2
a multilayer focusing lens part installed below the multi-focal diffractive lens part inside the housing part to focus the beam that has passed through the multi-focal diffractive lens part
Implementation Method 3
This apparatus generates nonlinear optical absorption proportional to the intensity of the incident beam in a medium with almost no linear absorption, thus enabling processing
Data Source
AI summary
The present disclosure relates to a laser processing apparatus that forms a ring beam with a uniform energy distribution and outputs a laser beam with a long focal depth and small focal size. The laser processing apparatus may include: a housing part having an incident hole and an output hole; an aperture part installed inside the housing part below the incident hole, which adjusts the size of the incident beam passing through the incident hole; a multi-focus diffractive lens part installed inside the housing part below the aperture part, which deflects the incident beam along the optical axis in multiple orders, simultaneously diffracting the deflected beam to form a circular beam; a multilayer focus lens part installed inside the housing part below the multi-focus diffractive lens part, which focuses the beam that has passed through the multi-focus diffractive lens part.