Ultra-Thin Glass Sheet Separation for High Edge Strength
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Solution Overview
Problem
Existing methods for producing ultra-thin glass sheets face challenges in achieving high edge strength, particularly at high annealing rates which can lead to internal stresses and reduced edge strength.
Innovation Solution
A method involving hot forming and annealing of a continuous glass ribbon, followed by introducing predetermined breaking lines using ultra-short pulsed lasers, allowing for controlled separation and achieving high edge strength regardless of annealing rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high annealing rates are used to maintain glass ribbon stability at high drawing rates, then productivity is improved, but internal stresses increase and edge strength deteriorates
Solution Approach 1:
The patent applies preliminary action by introducing predetermined breaking lines into the glass ribbon before the final cutting process. These breaking lines are created using laser filamentation technology, which generates controlled micro-fractures that guide the subsequent separation process. By pre-defining the break locations and patterns, the glass can be separated more easily and cleanly, compensating for the edge strength reduction caused by high annealing rates.
Solution Approach 2:
The patent replaces traditional mechanical cutting methods with laser-based filamentation. Instead of using physical contact between cutting tools and glass, the system uses ultra-short pulsed lasers to create filamentary defects within the glass structure. This non-contact method introduces breaking lines without mechanical stress, allowing high-speed processing while maintaining control over the separation process and reducing the negative impact of high annealing rates on edge quality.
2Manufacturing precision
If high annealing rates are applied to thin glass ribbons, then warpage and thickness variations are reduced, but internal stresses increase and edge strength decreases
Solution Approach 1:
The patent applies local quality by creating localized breaking lines at specific positions within the glass ribbon using laser filamentation. The laser energy is concentrated at predetermined locations to generate filamentary defects, while the rest of the glass structure remains unaffected. This localized approach allows control over separation behavior without uniformly affecting the entire glass ribbon, thereby maintaining thickness uniformity while managing edge strength through targeted structural modifications.
Solution Approach 2:
The patent changes the physical state and structural parameters of the glass by introducing filamentary defects through laser irradiation. By controlling laser parameters such as pulse duration, energy density, and scanning speed, the system creates specific micro-structural changes in the form of breaking lines. These parameter changes enable the glass to be separated along predetermined paths while compensating for the adverse effects of high annealing rates on edge strength.
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 method effectively produces glass sheets with high edge strength, even at high annealing rates, by optimizing the annealing rate based on glass thickness and using laser filamentation for precise breaking line introduction.
Implementation Method 1
generating a laser beam by at least one ultra-short pulsed laser; producing a focus area of the laser beam using beam-shaping optics such that the focus area is longer than the glass thickness of the glass ribbon; introducing predetermined breaking lines consisting of filamentary defects into the glass ribbon using the laser beam
Implementation Method 2
annealing the glass ribbon with an annealing rate that is chosen as a function of the predefined glass thickness, the annealing rate preferably being increased as the glass thickness decreases
Data Source
AI summary
A method for producing ultra-thin glass sheets is provided that results in glass sheets with high edge strength. The method includes: hot forming a continuous glass ribbon with a glass thickness from molten glass; annealing the glass ribbon with an annealing rate chosen based on the glass thickness; producing a laser beam focus area that is longer than the glass thickness; introducing filamentary defects into the glass ribbon using the laser beam so that the filamentary defects extend from one face to the opposite face and are spaced apart from one another along the breaking lines to produce transverse breaking lines and longitudinal breaking lines with margins each comprising a thickened bead; separating the beads along the longitudinal breaking lines and separating glass sheets by severing along the transverse breaking lines.