Chemically Strengthened Glass Surface Strength via Hydrogen Control
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Solution Overview
Problem
Chemically strengthened glass with phosphorus content faces challenges in achieving sufficient surface strength due to water resistance issues and the need for polishing, which can lead to scratches and warpage, while existing methods for improving surface strength at high temperatures result in inadequate compressive stress layer depth and surface roughness.
Innovation Solution
A chemically strengthened glass with a specific composition and treatment process, including a compressive stress layer formed by ion exchange, surface roughness of 0.50 nm or more, and hydrogen concentration profiles within specific ranges, to enhance surface strength without polishing or etching, ensuring a depth of 55 μm or more for the compressive stress layer and maintaining reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If chemical strengthening treatment is performed at high temperature (400°C or more) and for short time to improve productivity and increase compressive stress layer depth, then productivity and compressive stress layer depth are improved, but surface strength is lowered
Solution Approach 1:
The invention changes the chemical composition parameters of the glass, specifically controlling phosphorus content at 0.1-10 mass% and water content at 3-15 mass%, to enable the glass to achieve sufficient surface strength after high-temperature chemical strengthening treatment without requiring polishing, thereby resolving the contradiction between productivity improvement through high-temperature treatment and surface strength maintenance
2Strength
If polishing is performed after chemical strengthening treatment to improve surface strength, then surface strength is improved, but glass surface may get scratched and warpage increases
Solution Approach 1:
The invention performs preliminary control of glass composition (phosphorus and water content) before chemical strengthening treatment to pre-establish the conditions necessary for maintaining surface strength after high-temperature treatment, eliminating the need for subsequent polishing and avoiding the harmful effects of polishing-induced scratches and warpage
3Strength
If glass contains phosphorus to affect hydrogen concentration profile for improving surface strength, then surface strength can be improved, but water resistance deteriorates and glass is easily eroded by water
Solution Approach 1:
The invention optimizes the balance between phosphorus content (0.1-10 mass%) and water content (3-15 mass%) to achieve a hydrogen concentration profile that improves surface strength while maintaining adequate water resistance, preventing excessive erosion by water that would occur with high phosphorus content alone
4Strength
If hydrogen concentration profile is adjusted within specific range to improve surface strength without polishing, then surface strength is improved, but compressive stress layer depth becomes insufficient when treated at high temperature
Solution Approach 1:
The invention adjusts glass composition parameters (phosphorus and water content) to control hydrogen concentration profile in a way that enables sufficient compressive stress layer depth formation even during high-temperature chemical strengthening treatment, while still achieving the required surface strength without polishing
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 significantly improves the surface strength and reliability of the glass by maintaining a sufficient compressive stress layer depth and surface roughness, while avoiding the drawbacks of high-temperature treatments and polishing, thus providing enhanced durability and resistance.
Implementation Method 1
a compressive stress layer formed in a surface layer of the glass by an ion exchange method
Data Source
AI summary
The purpose of the present invention is to provide a chemically strengthened glass in which reduction in glass surface strength is effectively suppressed even without performing a polishing treatment after a prolonged chemical strengthening treatment has been conducted at a high temperature. The present invention relates to a chemically strengthened glass having a specific glass composition, wherein: the surface roughness (Ra) is a specific value or greater; the compressive stress layer depth of a surface layer is a specific value or greater; by setting the hydrogen concentration in the glass surface layer to be within a specific range, the surface strength of the glass is dramatically improved even without performing an etching treatment using hydrofluoric acid or polishing the glass surface after a prolonged chemical strengthening treatment has been conducted at a high temperature.