Glass Composition Matching for Curved Laminate Co-Forming
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Solution Overview
Problem
Conventional methods for forming curved glass laminates face issues with shape mismatch and optical distortions due to differences in composition, thickness, and viscosity between glass plies, leading to increased contact pressure and bending dot defects during the co-forming process.
Innovation Solution
Modify the composition of the thicker glass ply to match the viscosity curve of the thinner, strengthened glass ply, ensuring annealing and softening temperatures are within 35°C of each other, and both are above 550°C and 750°C, respectively, to achieve consistent sagging and reduce shape mismatch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If glass plies of different compositions and thicknesses are used in a laminate, then the laminate can achieve desired optical and mechanical properties, but shape mismatch and optical distortions occur during co-forming
Solution Approach 1:
The patent modifies the chemical composition parameters of the thicker glass ply by adjusting oxide contents (SiO2, Al2O3, CaO, MgO, Na2O, K2O) to change its viscosity characteristics. This parameter change enables the glass plies to have matching viscosity curves during co-forming, eliminating shape mismatch while maintaining composition variety for optimal optical and mechanical properties.
Solution Approach 2:
The invention applies different glass compositions to different plies in the laminate, with the thicker ply having modified composition to match the viscosity of the thinner ply. This local differentiation allows each ply to maintain its optimal properties while ensuring compatibility during co-forming operations.
2Strength
If thicker glass plies are used, then the laminate achieves desired strength and durability, but co-forming becomes difficult due to viscosity differences
Solution Approach 1:
The patent changes the chemical composition parameters of the thicker glass ply to adjust its viscosity-temperature characteristics. By controlling oxide contents, the thicker ply's viscosity curve is matched to the thinner ply, enabling easy co-forming while maintaining the thickness advantage for strength and durability.
3Adaptability or versatility
If glass plies with different viscosity curves are co-formed, then the process can accommodate various glass types, but contact pressure increases causing bending dot defects
Solution Approach 1:
The patent modifies the composition parameters of the thicker glass ply to align its viscosity curve with the thinner ply. This parameter adjustment ensures both plies have matching flow characteristics during co-forming, preventing excessive contact pressure and bending dot defects while maintaining versatility in glass type selection.
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 modified composition results in equal sag depths and reduced shape deviations of ±5 mm or less, minimal optical distortion, and lower membrane tensile stress, improving the consistency and quality of curved glass laminates.
Implementation Method 1
the stack is heated to a sagging temperature such that a shaped stack is formed
Implementation Method 2
The first annealing temperature is within 35° C. of the second annealing temperature, and both the first annealing temperature and the second annealing temperature are at least 550° C.
Implementation Method 3
The first softening temperature is within 35° C. of the second softening temperature, and both the first softening temperature and the second softening temperature are at least 750° C.
Data Source
AI summary
Embodiments of a method for pair bending glass articles is provided herein. In the method, a first glass article and a second glass article are stacked to form a stack. The first glass article includes a first surface, a second surface that opposes the first surface, and a first composition having first annealing and softening temperatures. The second glass article includes a third surface, a fourth surface that opposes the third surface, and a second composition having second annealing and softening temperatures. The annealing temperatures are within 35° C. of each other and are at least 550° C. The softening temperatures are within 35° C. of each other and are at least 750° C. In the method, the stack is placed on a mold, and the stack is heated to a sagging temperature such that a shaped stack is formed.