Oblique Laser Glass Separation for Thick Curved Cuts
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Solution Overview
Problem
Existing methods for separating glass portions along non-rectilinear lines, such as curved or closed-loop shapes, face difficulties due to the reduction in filament length with increasing angle of incidence and depth, leading to challenges in processing thicker glass pieces with oblique cuts, especially when the angle exceeds 5°, as they result in reduced filament lengths and increased refraction distortion.
Innovation Solution
The method employs an ultrashort pulse laser to create obliquely extending filamentary damages along the separation line within the glass or glass ceramic elements, using a beam shaping system to ensure deterministic damage zones, and a cleaving step with a CO2 laser to induce thermo-mechanical stresses for crack formation, allowing for precise separation without material removal and minimizing jamming risks, especially in thicker pieces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the angle of incidence of the laser beam is increased to create oblique cuts, then the oblique edge angle is improved, but the filament length decreases
Solution Approach 1:
The patent applies preliminary action by first creating filamentary damages with the ultrashort pulse laser at a controlled angle of incidence (5°-30°) before the final separation step. These pre-formed filaments serve as stress concentration points that guide the subsequent crack propagation, allowing the separation to follow the desired oblique path even though the filaments themselves are shorter than they would be at normal incidence. The preliminary filament creation enables the final separation to achieve the required oblique angle without needing excessively long filaments.
2Length of stationary object
If the depth in the substrate of the starting point of the filament is increased to process thicker glass, then the processing depth is improved, but the filament length decreases
Solution Approach 1:
The patent addresses the depth-length tradeoff by introducing angular orientation as an additional dimension. Instead of creating long horizontal filaments, the laser beam is incident at an angle (5°-30°) to create filaments that extend obliquely through the substrate. This angular approach allows the filament projection on the surface to be shorter while the actual filament path through the thick glass remains sufficient to span the required depth. The oblique orientation effectively converts a one-dimensional depth problem into a two-dimensional solution involving both depth and angle.
3Shape
If the angle of incidence is increased beyond 5°, then oblique cuts are achieved, but refraction distortion increases
Solution Approach 1:
The patent applies parameter changes by systematically varying the angle of incidence within the optimized range of 5°-30°, rather than using a fixed angle. This controlled parameter adjustment allows optimization of the balance between achieving sufficient oblique cut angle and minimizing refraction distortion. The patent also changes the laser pulse characteristics (ultrashort duration) to reduce the overall interaction time and minimize cumulative refraction effects. By treating the angle as a可调 parameter rather than a fixed value, the system can adapt to different glass thicknesses and separation requirements while staying within the optimal distortion range.
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 efficient and reliable separation of glass or glass ceramic elements with oblique edges up to 20° or more, facilitating the detachment of inner hole portions and producing thicker glass pieces with precise oblique cuts, overcoming the limitations of prior art by maintaining filament length and reducing refraction distortions.
Implementation Method 1
the laser pulses generate a plasma within the volume of the glass or glass ceramic element which causes the filamentary damages
Implementation Method 2
high-energy laser pulses can be used to cause a formation of filaments in glass, as irreversible damages
Implementation Method 3
a cleaving step with a CO2 laser to induce thermo-mechanical stresses for crack formation
Implementation Method 4
the length of the produced filaments decreases with increasing angle of incidence of a laser beam that is incident obliquely on the first substrate surface and with increasing depth in the substrate of the starting point of the filament in the substrate
Data Source
AI summary
A method includes producing filamentary damages in a volume of a glass or glass ceramic element that are adjacently aligned along a separation line and that extend obliquely relative to a surface of the glass or glass ceramic element, and separating a portion from the glass or glass ceramic element along the separation line. The step of producing the filamentary damages includes directing laser pulses of an ultrashort pulse laser obliquely on the surface so that the laser pulses have a light propagation direction that extends obliquely relative to the surface and so that the filamentary damages resulting from the laser pulses have the longitudinal extension that extends obliquely relative to the surface, generating a plasma within the volume with the laser pulses, and displacing the laser pulses at points of incidence over the surface along the separation line.