Glass Substrate Composition for Small-Taper Through-Hole Etching
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Solution Overview
Problem
Existing methods for forming through holes in glass substrates for micro LED displays result in tapered shapes with large taper angles, requiring larger opening diameters to maintain inner diameter dimensions, which complicates achieving high pixel densities and increases manufacturing costs due to phase separation and reduced meltability issues.
Innovation Solution
A glass substrate composition is formulated with specific ranges of SiO2, Al2O3, B2O3, Li2O+Na2O+K2O, MgO, CaO, SrO, BaO, and SnO2, along with controlled molar ratios, to achieve a low etching rate and reduce taper angles, ensuring high meltability and preventing phase separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the content of SiO2 in the glass substrate is increased to reduce the etching rate, then the etching rate decreases and taper angle is reduced, but the meltability decreases and melting cost increases
Solution Approach 1:
The patent applies parameter changes by precisely adjusting the glass composition parameters within specific ranges: SiO2 at 65-80 mol%, Al2O3 at 5.2-25 mol%, B2O3 at 0-15 mol%, and controlled amounts of alkali and alkaline earth metal oxides. This systematic parameter optimization allows the glass to achieve both low etching rate (≤2.00 μm/min) and good meltability simultaneously, resolving the contradiction between precision and ease of manufacture
Solution Approach 2:
The patent creates a composite glass material system that combines multiple oxide components in specific proportions. The synergistic composition of SiO2, Al2O3, B2O3, and controlled amounts of modifying oxides (Li2O, Na2O, K2O, MgO, CaO, SrO, BaO) produces a glass with balanced properties: sufficient etching resistance for precision through-hole formation while maintaining meltability for cost-effective manufacturing
2Ease of manufacture
If glass components other than SiO2 are adjusted to enhance meltability, then the meltability improves, but the glass is likely to undergo phase separation and become cloudy with reduced transmittance
Solution Approach 1:
The patent resolves this contradiction by changing the parameters of glass composition within optimized ranges. The specific content ranges of Al2O3 (5.2-25 mol%), B2O3 (0-15 mol%), and modifying oxides (MgO 0-15 mol%, CaO 0-15 mol%, SrO 0-15 mol%, BaO 0-2.9 mol%) are carefully controlled to enhance meltability while preventing phase separation. The total of MgO+CaO+SrO+BaO is maintained at 1-20 mol%, ensuring both manufacturability and compositional stability
Solution Approach 2:
The patent applies homogeneity by ensuring uniform distribution and compatible interaction of all glass components. The balanced composition with SiO2 (65-80 mol%) as the primary network former, Al2O3 (5.2-25 mol%) as a stabilizer, and controlled amounts of modifying oxides creates a homogeneous glass structure that resists phase separation while maintaining good meltability and optical clarity
3Productivity
If the opening diameter of the through hole is reduced to increase pixel density, then the pixel density increases, but the taper angle must be reduced to maintain inner diameter dimensions
Solution Approach 1:
The patent applies preliminary action by pre-modifying the glass substrate with laser irradiation before chemical etching. This creates a modified portion with altered physical and chemical properties that controls the etching progression, enabling the formation of through holes with small taper angles even at reduced opening diameters. This preliminary modification allows high pixel density to be achieved while maintaining precise control over through hole shape and dimensions
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 allows for the formation of through holes with small taper angles, enhancing pixel density and display reliability while maintaining excellent meltability and reducing manufacturing costs.
Implementation Method 1
there is known a method of forming a through hole by, for example, preparing a modified portion inside a glass substrate by irradiation with laser light and then removing the modified portion by chemical etching
Implementation Method 2
preparing a modified portion inside a glass substrate by irradiation with laser light
Data Source
AI summary
A glass substrate according to the present invention contains, as a glass composition, in mol %, from 65% to 80% of SiO2, from 5.2% to 25% of Al2O3, from 0% to 15% of B2O3, from 0.001% to less than 0.1% of Li2O+Na2O+K2O, from 0% to 15% of MgO, from 0% to 15% of CaO, from 0% to 15% of SrO, from 0% to 2.9% of BaO, from 1% to 20% of MgO+CaO+SrO+BaO, and from 0% to 1% of SnO2.