Glass Substrate Strengthening via Melted Coating Stress
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Solution Overview
Problem
Conventional methods for strengthening glass substrates used in storage devices, such as chemical strengthening and polishing, are expensive and inefficient, particularly for glass with less alkaline ions, and do not effectively address micro cracks at the inner diameter edges.
Innovation Solution
A method involving immersion of glass substrates in a solution containing a solvent like water and a coating material like NaOH, KOH, or KNO3, followed by evaporation and heating at a temperature sufficient to melt the coating material without exceeding the glass's transition temperature, generating compressive stress and enhancing mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional chemical strengthening or polishing methods are used, then glass substrate strength is improved, but the process becomes expensive and inefficient
Solution Approach 1:
The patent changes the chemical parameters of the strengthening solution by using ammonium hydroxide (NH4OH) instead of conventional molten salt baths or polishing slurries. This parameter change enables effective strengthening at lower costs and improved efficiency while achieving the required mechanical strength enhancement
Solution Approach 2:
The patent replaces mechanical polishing methods with a chemical treatment process using ammonium hydroxide solution. This substitution eliminates the need for expensive and time-consuming mechanical polishing while achieving equivalent or superior strength improvement through chemical modification of the glass surface
2Strength
If conventional chemical strengthening with molten salt baths is used, then compressive stress is generated, but the process is expensive and inefficient
Solution Approach 1:
The patent modifies the chemical composition and temperature parameters of the strengthening solution, using ammonium hydroxide at controlled temperatures and concentrations. This enables faster treatment times compared to conventional molten salt baths while maintaining effective compressive stress generation
Solution Approach 2:
The patent applies a preliminary coating or treatment to the glass substrate before the main strengthening process, or uses pre-heating of the ammonium hydroxide solution to optimize the strengthening reaction. This preliminary action reduces the overall process time by preparing the substrate or solution in advance
3Adaptability or versatility
If ion implantation or vapor exposure methods are used, then glass with less alkaline ions can be treated, but the process remains expensive and inefficient
Solution Approach 1:
The patent develops a universal ammonium hydroxide-based strengthening solution that works effectively across different glass compositions, including those with varying alkaline ion content. This single process replaces multiple specialized processes (ion implantation, vapor exposure) and achieves broad compatibility while reducing costs and improving efficiency
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
This process significantly increases the mechanical strength of glass substrates by about 50% to 100% for borosilicate and aluminosilicate glasses, respectively, while being potentially more cost-effective and efficient compared to conventional methods.
Implementation Method 1
heating the glass substrate at a preselected temperature for a preselected duration, where the preselected temperature is sufficient to substantially melt the coating material
Implementation Method 2
allowing the solvent to evaporate from the glass substrate
Implementation Method 3
heating the glass substrate at a preselected temperature for a preselected duration, where the preselected temperature is sufficient to substantially melt the coating material and is less than a transition temperature of the glass substrate
Data Source
AI summary
Methods for improving the strength of glass substrates are described. One such method for strengthening a glass disk substrate for a storage device includes immersing at least a portion of the glass substrate in a solution, the solution including a solvent and a coating material selected from the group consisting of NaOH, KOH, and KNO3, removing the glass substrate from the solution, allowing the solvent to evaporate from the glass substrate, and heating the glass substrate at a preselected temperature for a preselected duration, where the preselected temperature is sufficient to substantially melt the coating material and is less than a transition temperature of the glass substrate.