Laser Beam Splitting for Homogeneous Transparent Material Processing

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Solution Overview

Problem

Existing methods for laser processing of transparent materials struggle to control and reproduce material modifications uniformly across different depths, leading to inconsistent material separation and quality.

Innovation Solution

The method involves splitting an input laser beam into multiple partial beams using a beam splitting element with phase imprinting, forming focus elements with varying intensities and spatial positions to create uniform material modifications regardless of depth, facilitating improved material separation and homogeneity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a single focus element is used for laser processing, then the device complexity is low, but the manufacturing precision and homogeneity of material modifications at different depths deteriorate

Engineering Contradiction:
Improvehomogeneity of material modificationsVSAvoidbeam splitting element complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention divides a single laser beam into multiple partial beams using a beam splitting element, creating multiple focus elements at different depths and positions. This segmentation allows independent intensity control for each focus element, enabling homogeneous material modifications throughout the workpiece volume despite the increased device complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The beam splitting element is designed to create focus elements with spatially varying intensities, where each focus element has a specific intensity optimized for its depth position. This local quality approach ensures that material modifications are homogeneous throughout the volume, with lower intensities for shallow modifications and higher intensities for deep modifications.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If multiple focus elements with different intensities are formed, then the homogeneity of material modifications is improved, but the device complexity increases due to the beam splitting element

Engineering Contradiction:
Improvehomogeneity of material modificationsVSAvoidphase imprinting mechanism
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention replaces complex mechanical beam adjustment systems with a phase imprinting mechanism that uses optical phase modulation to control focus element intensities. This substitution achieves the same homogeneity improvement while reducing mechanical complexity and increasing system stability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The beam splitting element modifies the optical phase parameter of the laser beam to create multiple focus elements with different intensities. By changing the phase distribution across the beam cross-section, the system achieves homogeneous material modifications without requiring complex mechanical adjustments.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If focus elements with varying intensities are used, then the material separation quality is improved, but the energy distribution becomes more complex

Engineering Contradiction:
Improvematerial separation qualityVSAvoidenergy distribution complexity
Core Design Contradiction:
Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The system optimizes energy distribution by varying the intensity parameter of each focus element according to its depth position. Lower intensities are assigned to shallow focus elements and higher intensities to deep focus elements, achieving high-quality material separation while managing energy distribution through controlled parameter variation rather than uniform high energy input.

Inventive Principle:
Principle #35Parameter changes

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

This approach enables controlled and homogeneous material modifications, enhancing the quality and consistency of material separation, particularly through optimized separability and smoother edges, even in transparent materials like glass.

Implementation Method 1

the splitting of the input laser beam is carried out by means of the beam splitting element by phase imprinting on a beam cross-section of the input laser beam

Methodology Applied
Scientific EffectPhase imprinting: Phase Modulation

Implementation Method 2

an input laser beam is split into a plurality of partial beams by means of a beam splitting element, wherein the splitting of the input laser beam is carried out by means of the beam splitting element by phase imprinting

Methodology Applied
Scientific EffectDiffraction: Diffraction

Implementation Method 3

partial beams coupled out of the beam splitting element are focused by means of focusing optics, wherein a plurality of focus elements are formed by focusing the partial beams

Methodology Applied
Scientific EffectFocusing: Focusing

Data Source

PatentEP4380903B1Method and apparatus for laser processing of a workpiece
Publication Date: 2025.07.16 TRUMPF LASER & SYSTEMTECHNIK SE
  • EP4380903B1 patent drawingFigure 1
  • EP4380903B1 patent drawingFigure 2
  • EP4380903B1 patent drawingFigure 3

AI summary

The present invention relates to a method for laser processing of a workpiece (104) comprising a material (102) which is transparent for the laser processing, wherein an input laser beam (108) is split into a plurality of partial beams (116) by means of a beam splitting element (106), in which case the splitting of the input laser beam (108) by means of the beam splitting element (106) is effected by phase imposition on a beam cross section (112) of the input laser beam (108), partial beams (116) coupled out from the beam splitting element (106) are focused by means of a focusing optical unit (118), a plurality of focus elements (120) are formed by focusing of the partial beams (116), and wherein the material (102) of the workpiece (104), for the purpose of laser processing, is impinged on by at least one subset of the focus elements (120) formed. The phase imposition is effected by means of the beam splitting element (106) in such a way that at least two of the focus elements (120) formed have a different intensity (I).