Planar Glass Section Separation Along Curved Filament Lines

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Solution Overview

Problem

Existing methods struggle to efficiently separate sections from planar glass elements along non-straight dividing lines without causing further damage or cracking, particularly when the dividing lines are curved, angled, or closed, leading to high costs and the production of splinters.

Innovation Solution

The method involves creating filament-shaped defects in the glass element using ultrashort pulse lasers, followed by heating and/or cooling to induce tensile stresses along the dividing line, allowing the section to detach cleanly from the main part without additional cuts or damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional laser methods are used to separate glass along non-straight dividing lines, then separation is achieved, but further damage and cracking occur in both parts

Engineering Contradiction:
Improveseparation qualityVSAvoiddamage and cracking
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by creating filament structures within the glass material before separation. These filaments are formed by focused laser pulses that deposit energy along the desired separation path, creating a predetermined breaking line. When mechanical stress is subsequently applied, the glass separates cleanly along this pre-defined path without causing damage to the separated parts, as the filaments guide the fracture precisely where intended.

Inventive Principle:
Principle #10Preliminary action

2Ease of manufacture

If additional cuts are made to separate sections along curved or closed dividing lines, then separation is achieved, but production costs increase

Engineering Contradiction:
Improveseparation processVSAvoidproduction time
Core Design Contradiction:
Ease of manufactureVSLoss of time

Solution Approach 1:

The patent replaces mechanical cutting methods with a laser-based energy deposition system. Instead of using mechanical tools that would require multiple passes and additional cuts for curved or closed dividing lines, the system uses focused laser pulses to create filament structures that define the separation path. This substitution allows complex curved and closed contours to be separated in a single continuous operation, eliminating the need for additional cuts and reducing production time.

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

3Productivity

If mechanical separation methods are used on thick glass elements, then separation is achieved, but splinters are produced requiring further processing

Engineering Contradiction:
Improveseparation efficiencyVSAvoidedge quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by controlling the laser pulse parameters (energy, duration, focus) to create specific filament structures within the glass. By adjusting these parameters, the filaments are formed with precise dimensions and distribution along the separation path. When stress is applied, these controlled filaments guide the fracture to propagate cleanly along the dividing line, producing smooth edges without splinters, even in thick glass elements. This eliminates the need for further edge 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

This approach achieves a splinter-free, efficient separation of glass sections with high edge quality, reducing the risk of cracking and enabling reuse of both parts, while minimizing material waste and processing effort.

Implementation Method 1

A filament is formed by an ultrashort laser pulse, during which self-focusing occurs within the glass due to the Kerr effect until the energy density at a point becomes so high that a plasma is ignited.

Methodology Applied
Scientific EffectKerr effect: Kerr Effect

Implementation Method 2

irreversible damage in the form of filaments can be caused in a glass substrate using high-energy laser pulses

Methodology Applied
Scientific EffectLaser ablation: Laser Ablation

Implementation Method 3

the glass element is heated and expanded in the area of the main part and/or cooled and contracted in the area of the section, so that the section detaches from the main part along the separation line at the adjacent filament-shaped defects

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP3590898B1Complementary sections of a planar glass element
Publication Date: 2026.04.22 SCHOTT AG
  • EP3590898B1 patent drawingFigure 1(a)~1(d)
  • EP3590898B1 patent drawingFigure 2~4(h)
  • EP3590898B1 patent drawingFigure 5~6(f)

AI summary

The invention provides a set with two planar glass elements (2, 2', 3, 4), wherein the two-dimensional shape that one of the planar glass elements (2) has in its plane is complementary to the two-dimensional shape that the other of the planar glass elements (2', 3, 4) has in its plane, and wherein two edges (27, 28) of one planar glass element (2), which form the transition between the side surfaces (29, 30) and an edge surface (25) connecting these side surfaces (29, 30), each have the same shape as two edges (27', 28') of the other planar glass element (2', 3, 4), which form the transition between the side surfaces (29', 30') and an edge surface (25') connecting these side surfaces (29', 30'), and wherein in these edge surfaces (25, 25') of the two planar glass elements (2, 2', 3, 4) each have adjacent filament-shaped defects (26, 26') that form depressions in these edge surfaces (25,25') form, wherein the longitudinal direction of the filament-shaped damage (26, 26') runs in the direction from one edge (27, 27') to the other edge (28, 28').