High-Temperature KOH Etching of Aluminosilicate Glass for Low Haze
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Solution Overview
Problem
Aluminosilicate glass-based articles face challenges in achieving increased surface strength and decreased haze, making it difficult to form high-strength substrates for portable electronic devices.
Innovation Solution
A method involving contacting aluminosilicate glass-based articles with an etchant comprising greater than or equal to 30 wt % potassium hydroxide and less than or equal to 10 wt % sodium hydroxide at temperatures greater than or equal to 130°C, which uniformly etches the glass, reducing surface roughness and enhancing mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching methods are used on aluminosilicate glass, then the glass can be etched, but the surface roughness increases and haze increases, reducing mechanical strength and appearance quality
Solution Approach 1:
The patent changes the chemical composition parameters of the etchant by using potassium hydroxide as the primary base (30-100 wt%) instead of conventional sodium hydroxide, and controls the temperature parameter (130-300°C) to achieve uniform etching that reduces surface roughness (Sq ≤ 10 nm) while maintaining or improving mechanical strength
Solution Approach 2:
The etching process creates a localized modified layer on the glass surface with specific chemical composition and structure that differs from the bulk glass, providing enhanced surface properties including reduced roughness and improved strength while maintaining the overall glass integrity
2Manufacturing precision
If conventional etching methods are used on aluminosilicate glass, then the glass can be etched, but haze increases, reducing appearance quality
Solution Approach 1:
The patent changes the etchant composition to potassium hydroxide-based and controls temperature (130-300°C) and concentration parameters to achieve uniform etching that removes surface irregularities without creating light-scattering defects, resulting in decreased haze (≤ 1%) and improved appearance quality
3Productivity
If high temperature etching is used, then etching speed increases, but controlling surface quality becomes more difficult
Solution Approach 1:
The patent optimizes the temperature parameter range (130-300°C) and combines it with specific potassium hydroxide concentration (30-100 wt%) to achieve fast etching rates while maintaining excellent surface quality control, as the high concentration KOH provides aggressive etching capability even at moderate temperatures
4Strength
If sodium hydroxide-based etchants are used, then etching can proceed, but surface strength is not sufficiently improved and haze decreases
Solution Approach 1:
The patent changes the chemical base from sodium hydroxide to potassium hydroxide (30-100 wt%), which provides superior surface strengthening through ion exchange and etching mechanisms, achieving both increased surface strength and decreased haze in a single process step
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 method results in treated glass-based articles with reduced surface roughness (Sq ≤ 10 nm) and decreased haze (≤ 1%), improving mechanical performance and appearance.
Implementation Method 1
contacting an aluminosilicate glass-based article with an etchant, the etchant comprising: greater than or equal to 30 wt % and less than or equal to 100 wt % potassium hydroxide; and less than or equal to 10 wt % sodium hydroxide
Implementation Method 2
wherein a temperature of the etchant is greater than or equal to 130° C. during the contacting
Data Source
AI summary
A method of forming a treated glass-based article comprises: contacting an aluminosilicate glass-based article with an etchant, the etchant comprising: greater than or equal to 30 wt % and less than or equal to 100 wt % potassium hydroxide; and less than or equal to 10 wt % sodium hydroxide; and wherein a temperature of the etchant is greater than or equal to 130° C. during the contacting.