Diffuse-Finish Glass Sheets with Alternating Acid-Alkali Etching
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Solution Overview
Problem
Existing methods for producing diffuse glass surfaces are inefficient, requiring long processing times, high costs, or limited to treating only one side of the glass, making them unsuitable for industrial-scale production.
Innovation Solution
A batch-type industrial process involving alternating immersions of glass sheets in acidic and alkaline solutions to achieve a diffuse finish on both surfaces, using specific acid concentrations and durations to optimize roughness and reflection levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional acid treatment methods are used to reduce reflection, then reflection level is lowered to about 1%, but processing time is excessive and not practical for production
Solution Approach 1:
The patent changes the chemical parameters of the acid solution, specifically using hydrofluoric acid at concentrations of 0.1% to 10% (optimally 1% to 5%) instead of conventional stronger acids. This parameter change enables achieving the same anti-reflective effect (1% reflection) with dramatically reduced processing time (5 to 60 minutes versus hours), making the process industrially viable.
Solution Approach 2:
The patent implements periodic action through alternating immersion of glass sheets in acid and water baths. The glass is immersed in acid solution for a specific time to create the diffuse surface, then transferred to water to stop the reaction and prevent over-etching. This periodic cycling allows precise control of the etching process, achieving optimal reflection reduction without excessive processing time.
2Manufacturing precision
If strong mineral acids are used for etching, then diffuse finish is achieved, but the acid concentration decreases quickly requiring frequent solution changes
Solution Approach 1:
The patent uses weaker acid concentrations (0.1% to 10% hydrofluoric acid) instead of strong mineral acids. This parameter change slows the etching rate, allowing the acid solution to maintain effective concentration for longer periods. Consequently, solutions can be reused across multiple glass sheets without frequent changes, significantly improving production efficiency while maintaining consistent diffuse finish quality.
3Ease of manufacture
If only one side of glass is treated, then processing is simpler, but both surfaces need diffuse finish for artwork protection
Solution Approach 1:
The patent applies periodic action by repeatedly immersing the glass sheet in acid and water baths, flipping the sheet between immersions. The glass is immersed in acid, then transferred to water, flipped over, and immersed again in acid for the second surface. This systematic periodic process achieves diffuse finish on both surfaces while maintaining clear procedural steps, satisfying both ease of manufacture and application requirements.
Solution Approach 2:
The patent merges multiple operations into a unified batch process where multiple glass sheets are treated simultaneously in the same acid and water baths. By combining the treatment of multiple sheets and both surfaces into an integrated workflow, the process maintains simplicity while achieving the required dual-surface diffuse finish for artwork protection applications.
4Manufacturing precision
If long immersion times are used, then diffuse finish is achieved, but production speed decreases
Solution Approach 1:
The patent changes the acid concentration parameter to 0.1% to 10% hydrofluoric acid, which provides an optimal etching rate. This parameter change enables achieving the required surface roughness (0.8020 μm to 0.7081 μm average) within 5 to 60 minutes of immersion, compared to much longer times with conventional acids. The controlled concentration ensures consistent roughness while maintaining high production speed.
Solution Approach 2:
The patent implements feedback control through the alternating immersion process in acid and water baths. By transferring glass sheets between solutions at specific intervals, the process self-regulates the etching duration and intensity. This feedback mechanism ensures consistent surface roughness (0.8020 μm to 0.7081 μm) is achieved without requiring excessively long immersion times, thereby maintaining high production speed.
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 process efficiently achieves a diffuse finish on both sides of glass sheets with a reflection level of about 1% and average roughness of 0.8020 μm to 0.7081 μm, suitable for protecting artworks by minimizing glare while maintaining transparency.
Implementation Method 1
treating its surface with acidic solutions. This prevents glare by adding irregularities to the surface
Implementation Method 2
introducing the sheet or sheets of glass in an alkaline solution, such as a 2% solution of caustic soda. To facilitate removal of the crust, the caustic solution is subjected to a stirring by bubbling process
Data Source
AI summary
The present invention relates to a process for manufacturing glass sheets with diffuse finish and the resulting glass sheet by this process. The glass sheet is subjected to a series of alternate immersions in acidic solutions and alkaline solutions to remove impurities and waste and to generate a diffuse finish on both sides of the glass sheet. The process generates in the glass sheet in at least one side, a diffuse surface with a peak to valley roughness (Rt) of between 5.8343 μm and 9.3790 μm; an average roughness (Ra) value between 0.8020 μm and 0.9538 μm; an RMS roughness between 0.9653 μm and 1.1917 μm; a solar transmission between 84.8% and 46.50%; a solar reflection between 7.4 and 4.4%; a light transmission between 88.5% and 67.70%; a reflection of light between 6.50% and 5.20%; and UV transmission between 35.60% and 70.20%.