Alkaline Glass Etching in Organic Solvent for Fine Structures
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Solution Overview
Problem
Existing methods struggle to produce complex, high-quality glass structures with minimal damage and residue, particularly in water-based etching mediums, and are time-consuming.
Innovation Solution
A nearly water-free alkaline etching process using organic solvents with high boiling points, such as ethylene glycol, at elevated temperatures, combined with ultrashort pulse lasers to pre-damage glass and expand flaws, allowing for fast and cost-effective structuring of glass elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If water-based alkaline etching medium is used, then the etching process is simple and inexpensive, but the etching rate is slow (less than 8 μm per hour) and some glasses cannot be etched
Solution Approach 1:
The patent changes the fundamental parameter of the etching medium from water-based to organic solvent-based (specifically ethylene glycol). This parameter change enables higher operating temperatures (up to 190°C due to ethylene glycol's boiling point) and achieves etching rates of 20 μm per hour or more, resolving the contradiction between etching speed and process simplicity.
Solution Approach 2:
The patent utilizes the phase transition properties of organic solvents, particularly ethylene glycol's high boiling point, to enable etching at elevated temperatures. This allows the system to operate in a different thermal phase regime compared to water-based etching, achieving faster reaction kinetics and higher productivity without requiring complex pressurized systems.
2Manufacturing precision
If conventional etching methods are used, then the process is established and reliable, but it is time-consuming and produces damage, residues or stresses in the glass
Solution Approach 1:
The patent applies ultrashort pulse laser irradiation before the etching process to pre-damage the glass structure along the desired pattern. This preliminary action creates localized modification zones that guide subsequent etching, enabling precise structuring while reducing the actual etching time required and minimizing damage to surrounding areas.
Solution Approach 2:
The patent replaces conventional mechanical or slow chemical etching methods with a combined laser-chemical approach. The ultrashort pulse laser provides precise spatial control, while the organic solvent-based chemistry enables faster material removal, together achieving high precision with reduced process time and minimal residual stress.
3Adaptability or versatility
If water-based etching medium is used, then the system is simple, but some glasses with titanium compounds cannot be etched due to solid precipitation
Solution Approach 1:
The patent changes the chemical composition parameter of the etching medium from water-based to organic solvent-based (ethylene glycol). This parameter change prevents solid precipitation of titanium compounds during etching, enabling the processing of glass types containing titanium that are incompatible with water-based systems, thereby improving glass type compatibility.
4Productivity
If high etching rates are achieved, then productivity improves, but damage and residues in the glass increase
Solution Approach 1:
The ultrashort pulse laser pre-damages the glass along the precise desired pattern before etching begins. This preliminary structuring ensures that the high-rate chemical etching only removes already-compromised material, achieving fast glass removal rates (20 μm per hour or more) without creating additional damage or residue in the final product.
Solution Approach 2:
The organic solvent-based etching medium acts as an intermediary that enables fast material removal while being gentler on the glass structure compared to water-based systems. The unique chemical properties of ethylene glycol allow rapid etching of laser-prepared zones without causing excessive damage or residue, mediating between high productivity requirements and product quality.
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 achieves rapid glass removal rates of up to 20 µm per hour with minimal damage, enabling precise and efficient production of fine structures and cutouts in glass elements, including those with titanium compounds, without solid precipitation.
Implementation Method 1
the boiling point in specific organic solvents is much higher than the one of water-based alkaline etching medium. Therefore, etching in an organic solvent can be at higher temperatures and therefore much faster
Implementation Method 2
the glass element is pre-damaged with a laser beam of an ultrashort pulse laser by introducing flaws and wherein the flaws are expanded by the alkaline etching medium
Data Source
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AI summary
The invention is based on the object to provide a method for processing glass, wherein a glass element (1) is provided and glass material is removed of the glass element (1), whereby the removal is carried out by etching and wherein an alkaline etching medium (4) in an organic solvent is used.