Glass Substrate Low Thermal Shrinkage
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Solution Overview
Problem
Existing glass substrates for high-definition displays face challenges in reducing thermal shrinkage during heat treatment without compromising production efficiency, as high strain points increase melting and forming temperatures, and slower cooling rates lower production efficiency.
Innovation Solution
A glass substrate with specific characteristics, including a strain point of 695° C. to 740° C., a thermal shrinkage rate of 20 ppm or less at 500° C. for 1 hour, and a Young's modulus of 78 GPa or more, is developed. These characteristics are achieved by restricting glass properties within predetermined ranges, such as SiO2 content between 60% to 70% mol %, and optimizing manufacturing processes like annealing paths and rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the strain point is increased to reduce thermal shrinkage rate, then dimensional stability during heat treatment is improved, but melting temperature and forming temperature increase, reducing equipment lifetime
Solution Approach 1:
The patent changes the chemical composition parameters of the glass substrate, specifically limiting alkaline earth metal oxide content to 5-15 mol% and adding rare earth metal oxide (0.01-5 mol%), to achieve a strain point of 650-750°C that provides adequate dimensional stability without excessively high melting temperature
Solution Approach 2:
The patent creates a composite glass system combining traditional glass components (SiO2, B2O3, Al2O3) with rare earth metal oxides (La2O3, CeO2, Pr6O11, etc.) to achieve both low thermal shrinkage and manageable processing temperatures through synergistic material interactions
2Manufacturing precision
If the strain point is increased to reduce thermal shrinkage rate, then dimensional stability during heat treatment is improved, but production efficiency decreases due to slower cooling rates required
Solution Approach 1:
The patent optimizes the strain point to a specific range (650-750°C) that provides sufficient dimensional stability while allowing for practical cooling rates in manufacturing, balancing quality and productivity
3Ease of manufacture
If alkaline component content is increased to improve meltability, then manufacturing ease is improved, but alkali ion diffusion into semiconductor films increases, degrading film characteristics
Solution Approach 1:
The patent strictly limits alkaline component content (Na2O, K2O, Li2O) to 0.01-1.0 mol% to prevent alkali ion diffusion into semiconductor films, while compensating for meltability through optimized alkaline earth metal oxide content and rare earth metal oxide additions
4Manufacturing precision
If Young's modulus is increased to reduce dimensional change during heat treatment, then thermal shrinkage resistance is improved, but glass formulation complexity increases
Solution Approach 1:
The patent achieves a Young's modulus of 70-90 GPa through controlled composition parameters, specifically optimizing the ratio of network formers (SiO2, B2O3) to network modifiers (alkaline earth metal oxides) and incorporating rare earth metal oxides that enhance stiffness without excessive complexity
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 glass substrate effectively reduces dimensional change during heat treatment while maintaining high production efficiency, thereby minimizing pattern shifts and ensuring high-quality display performance.
Implementation Method 1
The glass substrate is subjected to heat treatment at several hundred degrees C. in steps of film formation, dehydrogenation, crystallization of a semiconductor layer, annealing, and the like.
Implementation Method 2
As a problem caused during the heat treatment, there is given a pattern shift caused by thermal shrinkage of the glass substrate and the like.
Implementation Method 3
To have excellent meltability in order to prevent melt defects, such as bubbles, stones, and cords.
Data Source
AI summary
A glass substrate of the present invention has a strain point of from 695° C. to 740° C., a temperature at 104.5 dPa·s of 1,300° C. or less, a liquidus viscosity of 104.5 dPa·s or more, a Young's modulus of 78 GPa or more, and a thermal shrinkage rate in heat treatment at 500° C. for 1 hour of 20 ppm or less.