Thin Glass Laser Cutting With Filament Damage Separation
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Solution Overview
Problem
Existing methods for cutting thin glasses are unstable and prone to uncontrolled separation due to low inherent stiffness, leading to reduced edge strength and accuracy, especially when handling thin glass substrates.
Innovation Solution
A method using an ultra-short pulse laser to create filamentary damages in thin glass sheets, combined with controlled tensile stress applied perpendicular to the damage path, allowing for precise separation and edge control by moving the laser and glass relative to each other, thereby eliminating the need for two-stage scoring and breaking processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional scoring and breaking processes are used to separate thin glass, then the glass can be separated along a predetermined line, but the process is unstable and leads to uncontrolled separation with reduced edge strength due to the low inherent stiffness of thin glass
Solution Approach 1:
The patent divides the separation process into two distinct stages: (1) inserting filamentary damages using ultra-short pulse laser, and (2) applying tensile stress to propagate cracks along the damage path. This segmentation allows each stage to be optimized independently, improving both precision and reliability
Solution Approach 2:
The patent applies preliminary action by first inserting filamentary damages along the desired separation path using laser irradiation before applying any separating force. This pre-damage insertion creates a controlled weakness path that guides subsequent crack propagation, ensuring precise separation even in thin glass with low stiffness
2Manufacturing precision
If laser-induced tension-crack-separation is used on thin glass, then separation can be achieved, but the process is unstable and produces three-dimensional distortions (humps) due to difficulty in building up sufficient temperature gradient
Solution Approach 1:
The patent replaces the conventional CO2 laser thermal process with ultra-short pulse laser irradiation. This substitution changes the mechanism from thermal diffusion (which causes humps) to direct filamentary damage insertion, eliminating temperature gradient issues and associated distortions
Solution Approach 2:
The patent changes key process parameters by using ultra-short pulse duration and specific energy density ranges (0.1-10 J/cm²) to achieve filamentary damage without excessive heating. This parameter optimization prevents thermal distortion while maintaining effective separation
3Strength
If diamond scoring tools are used to insert superficial damage in glass, then very firm edges can be produced, but the diamond tools are very sensitive and can be damaged when placed on the glass
Solution Approach 1:
The patent replaces mechanical diamond scoring tools with ultra-short pulse laser irradiation. This substitution eliminates mechanical contact between the tool and glass, removing the risk of tool damage while still achieving controlled damage insertion along the desired separation path
Solution Approach 2:
The patent introduces light (laser beam) as an intermediary to transfer energy to the glass for damage insertion. This intermediary approach allows precise control of the damage process without direct mechanical contact, protecting both the tool and the glass from damage
4Ease of operation
If thin glass sheets are handled during the separation process, then the glass can be transported and processed, but the low inherent stiffness causes uncontrolled breakage and reduced edge strength due to inadvertent tensile stresses
Solution Approach 1:
The patent performs preliminary damage insertion along the exact separation path before any handling or stress application. This ensures that even if inadvertent stresses occur during handling, the cracks will propagate only along the pre-defined damage path, maintaining precision and edge strength
Solution Approach 2:
The patent applies preliminary anti-action by creating controlled filamentary damages that preemptively guide crack propagation. This prevents uncontrolled breakage during subsequent handling by ensuring that stress concentrations occur only at the intended separation locations
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 reliable, stable, and controlled separation of thin glass sheets with high edge quality, reducing the risk of uncontrolled breakage and achieving precise edge contours, even in very thin glass sheets down to 30 μm thickness.
Implementation Method 1
the glass sheet is irradiated with a pulsed laser beam of an ultra-short pulse laser, the light intensity of the laser beam inside the glass sheet is so high, that the laser beam leaves a filamentary damage along its path through the glass sheet
Implementation Method 2
during the insertion of the filamentary damages, a tensile stress acting on the glass at the filamentary damages and preferably in the direction transverse, in particular perpendicular to the path of the adjacent filamentary damages is applied to at least one surface of the glass sheet, so that the glass sheet separates along the path
Data Source
AI summary
A method is provided that includes providing a glass sheet of a thickness of at most 300 μm and irradiating the glass sheet with a pulsed laser beam. The laser beam has a light intensity inside the glass sheet leaves a filamentary damage along its path through the glass sheet. The laser beam and the glass sheet are moved relative to each other so that due to the pulses of the laser beam filamentary damages are inserted next to one another along a path running on the glass sheet. During the insertion of the filamentary damages, a tensile stress is applied on the glass at the filamentary damages and in the direction transverse to the path of the adjacent filamentary damages so that the glass sheet separates along the path during insertion of the filamentary damages.