Glass Substrate Composition for Display Panels with Low Heat Shrinkage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current glass substrates for high-definition displays face challenges with heat shrinkage, leading to uneven pixel pitch and increased productivity costs, particularly when using direct electrical heating, which can cause erosion of melting tanks due to high specific resistance of molten glass, and existing solutions do not adequately address the need for both low devitrification temperature and high strain point.
Innovation Solution
A glass substrate composition comprising SiO2, Al2O3, B2O3, and BaO, with specific ranges to achieve a devitrification temperature of 1235°C or lower and a strain point of 720°C or higher, along with controlled heat treatment to maintain a heat shrinkage rate of 15 ppm or less, and an etching rate higher than 75 μm/h, using direct electrical heating and controlled annealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the strain point of glass substrate is increased to decrease heat shrinkage, then heat shrinkage rate is reduced, but specific resistance of molten glass increases causing erosion of melting tank
Solution Approach 1:
The patent applies parameter changes by precisely controlling the chemical composition parameters of the glass substrate to achieve a strain point of 725°C or higher while maintaining specific resistance of molten glass at 200 Ω·cm or lower. The glass composition includes SiO2 (60-80 wt%), Al2O3 (10-20 wt%), B2O3 (0.1-5 wt%), and specific amounts of BaO (2-10 wt%), SrO (2-10 wt%), and CaO (5-15 wt%). This compositional parameter optimization allows direct electrical heating to melt the glass efficiently without causing tank erosion, while simultaneously achieving low heat shrinkage rate of 20 ppm or less.
2Productivity
If direct electrical heating is used for efficient melting of glass, then melting efficiency is improved, but erosion and wear of melting tank occurs due to high specific resistance
Solution Approach 1:
The patent optimizes the electrical conductivity parameter of molten glass by controlling the glass composition, specifically adding BaO (2-10 wt%), SrO (2-10 wt%), and CaO (5-15 wt%) which reduce the specific resistance to 200 Ω·cm or lower. This parameter change enables efficient direct electrical heating for glass melting while preventing excessive current flow through the refractory tank materials, thereby eliminating erosion and wear problems.
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 solution effectively reduces heat shrinkage, maintains high strain point, and increases productivity by optimizing the glass substrate's composition and processing conditions, preventing tank erosion and enabling efficient production of high-definition displays.
Implementation Method 1
heat shrinkage of glass substrates during production of display panels
Implementation Method 2
controlled annealing
Implementation Method 3
direct electrical heating
Data Source
AI summary
Provided are: a glass substrate that achieves a high strain point while having a low devitrification temperature; and a method for producing said glass substrate. This glass substrate for a display is made of a glass comprising SiO2 and Al2O3, comprising 0% or more to less than 3% B2O3 and from 5 to 14% BaO in mass %, and substantially devoiding Sb2O3, wherein the devitrification temperature is 1235° C. or lower and the strain point is 720° C. or higher. Alternatively, this glass substrate for a display is made of a glass comprising SiO2 and Al2O3, comprising 0% or more to less than 3% B2O3, 1.8% or more MgO, and from 5 to 14% BaO in mass %, and substantially devoiding Sb2O3, wherein (SiO2+MgO+CaO)—(Al2O3+SrO+BaO) is less than 42%, the devitrification temperature is 1260° C. or lower, and the strain point is 720° C. or higher. This method for producing said glass substrate for a display comprises: a melting step for melting, by using at least direct electrical heating, a glass material prepared to have a predetermined composition; a forming step for forming, into a flat glass sheet, the molten glass that has been melted in the melting step; and an annealing step for annealing the flat glass sheet, wherein a condition for cooling the flat glass sheet is controlled so as to reduce the heat shrinkage rate of the flat glass sheet.