Polychromatic Laser Focal Line Control for Precise Glass Separation

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Solution Overview

Problem

Existing methods for cutting workpieces, particularly glass or glass ceramic, along a predetermined processing line using pulsed laser beams face challenges in achieving precise and reproducible separation due to inhomogeneous intensity distributions and difficulties in adjusting machining depth, leading to inadequate separating edges and imprecise cutting.

Innovation Solution

A device and method utilizing a pulsed, polychromatic laser beam with an optical arrangement featuring chromatic aberration for wavelength-dependent focusing and filtering, allowing for selective adjustment of machining depth and precise control over the focal line, enabling precise separation of workpieces by mechanical or thermal influences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a pulsed laser beam is used to cut glass or glass ceramic workpieces, then the cutting process can be performed, but the intensity distribution is inhomogeneous leading to imprecise cutting and inadequate separating edges

Engineering Contradiction:
Improvecutting precisionVSAvoidseparating edge quality
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent applies parameter changes by utilizing the wavelength-dependent focusing property of optical elements (chromatic aberration) to transform the intensity distribution of the laser beam. Different wavelengths are focused at different depths, creating a controlled intensity profile along the processing line that enables precise and reproducible separation with high-quality edges.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If conventional optical arrangements are used, then laser beam focusing is achieved, but the focal line intensity distribution is inhomogeneous and machining depth cannot be adjusted

Engineering Contradiction:
Improvemachining depth adjustmentVSAvoidfocal line intensity uniformity
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent employs parameter changes by exploiting chromatic aberration to achieve wavelength-dependent focusing. By selecting specific wavelengths from the broadband laser spectrum, the focal depth can be precisely adjusted while maintaining a homogeneous intensity distribution along the focal line, thus enabling both adaptability and precision.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies dynamics by making the focal line characteristics adjustable through wavelength selection. The system can dynamically adapt the machining depth and intensity distribution by tuning which wavelengths are transmitted through the optical arrangement, providing versatile control over the processing parameters.

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If a broadband laser beam is used, then a wide spectrum is available for processing, but the intensity distribution along the focal line becomes inhomogeneous

Engineering Contradiction:
Improvespectral rangeVSAvoidintensity distribution uniformity
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent applies the extraction principle by selectively transmitting only certain wavelength ranges from the broadband laser beam through the optical arrangement. By extracting and focusing specific wavelengths that contribute to homogeneous intensity distribution, the system maintains spectral versatility while eliminating the inhomogeneity caused by the full broadband spectrum.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses parameter changes by adjusting the spectral composition of the laser beam. Through wavelength-dependent filtering and focusing, the system transforms the broadband input into a controlled spectral output that produces a homogeneous intensity distribution along the focal line, enabling precise processing.

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

The solution enables precise and reproducible cutting of workpieces, particularly glass or glass-ceramic materials, by adjusting the machining depth and intensity distribution along the focal line, resulting in high-quality edges and improved separability.

Implementation Method 1

an optical arrangement (6) with chromatic aberration for wavelength-dependent focusing of the laser beam (5)

Methodology Applied
Scientific EffectChromatic aberration:

Implementation Method 2

with at least one filter (7) for wavelength-dependent filtering of the laser beam (5)

Methodology Applied
Scientific EffectWavelength-dependent filtering: Filter (optical)

Implementation Method 3

Using the Kerr effect, when the intensity of a laser beam is sufficiently high, there is a non-linear interaction between the electromagnetic field of the laser beam and a workpiece, resulting in self-focusing of the laser beam

Methodology Applied
Scientific EffectKerr effect: Kerr Effect

Implementation Method 4

The high intensity in the focus creates a plasma in the workpiece that defocuses the laser beam. If the intensity of the remaining laser beam is high enough, the laser beam is focused again, etc.

Methodology Applied
Scientific EffectLaser ablation: Laser Ablation

Data Source

PatentEP3624984B1Device for and method of dividing a workpiece along a predetermined processing line using a pulsed polychromatic laser beam and a filter
Publication Date: 2021.12.15 SCHOTT AG
  • EP3624984B1 patent drawingFigure 1
  • EP3624984B1 patent drawingFigure 2
  • EP3624984B1 patent drawingFigure 3

AI summary

The invention relates to a device and to a method for processing a workpiece (2) along a predetermined processing line, wherein the device comprises at least the following means: means for generating a pulsed, polychromatic laser beam (5), an optical arrangement (6) for generating a focal line along the beam direction of the laser beam (5), wherein the optical arrangement (6) has a chromatic aberration for wavelength-dependent focusing of the laser beam (5) and at least one filter (7) for wavelength-dependent filtering of the laser beam (5) and means for generating a relative movement between laser beam (5) and workpiece (2) along the predetermined processing line in order to process the workpiece (2) by means of the effect of the focused laser beam (5).