Sol-Gel Coating for Structured Optical Substrates
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for creating patterned coatings on substrates face limitations such as high tool wear, restricted structural diversity, and poor thermal stability, particularly in achieving thick, crack-resistant layers suitable for optical applications.
Innovation Solution
A sol-gel layer with a high modulus of elasticity, achieved through a composition rich in temperature-stable organosilicon compounds and polysiloxanes, is applied to the substrate, allowing for structured layers with thicknesses exceeding 5 μm and maintaining integrity under high temperature loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If hot embossing is used to structure the substrate, then structural patterns can be introduced, but tool wear increases and costs rise
Solution Approach 1:
The patent uses a master pattern to create a stamp that transfers the structural design to the sol-gel layer. This copying approach allows the same pattern to be reproduced multiple times without significant wear, as the master pattern remains unchanged while the stamp serves as a consumable intermediate that can be replaced rather than the expensive original master
Solution Approach 2:
The patent employs a stamp that can be replaced when worn, rather than using durable but expensive hot embossing tools. The stamp is a lower-cost, disposable element that transfers the pattern from the master, allowing economical production of structured layers without investing in high-cost, wear-prone hot embossing equipment
2Shape
If polymer layers are used for structuring, then patterning can be achieved, but thermal stability deteriorates
Solution Approach 1:
The patent creates a hybrid sol-gel layer combining organic precursors (tetraethyl orthosilicate, organosilicon compounds) with inorganic silica network formation. This composite material undergoes sol-gel transformation to form a ceramic-like structure that maintains the patterning capability of polymer layers while achieving the thermal stability of inorganic materials, stable up to temperatures exceeding 400°C
Solution Approach 2:
The patent transforms the material state from organic polymer to inorganic-ceramic hybrid through controlled sol-gel processing and thermal treatment. By changing the chemical composition and structural parameters during processing (hydrolysis, condensation, sintering), the layer transitions from thermally unstable polymer to thermally stable ceramic-like material while preserving the introduced patterns
3Length of stationary object
If solvent-based thin-layer paints are embossed, then layer thickness can be controlled, but crack resistance deteriorates at greater thicknesses
Solution Approach 1:
The patent uses a sol-gel coating composition containing tetraethyl orthosilicate and organosilicon compounds that form a hybrid organic-inorganic network. This composite structure provides both the thickness control capability of conventional paints and the crack resistance of ceramic materials, as the inorganic silica network forms a rigid, crack-resistant framework that maintains integrity at thicknesses exceeding 5 μm
Solution Approach 2:
The patent changes the fundamental material properties by using sol-gel precursors that undergo chemical transformation during drying and thermal treatment. The coating evolves from a solvent-based organic layer to a crosslinked gel network and finally to a ceramic-like inorganic structure, with each stage providing different mechanical properties that collectively achieve both thickness control and crack resistance
4Area of stationary object
If thixotropic embossing is used for large area rigid substrates, then structuring can be achieved, but process complexity increases
Solution Approach 1:
The patent employs a sol-gel coating composition that self-structures when a stamp is pressed into it during the coating process. The thixotropic properties of the sol-gel mixture allow it to be deposited as a uniform layer that automatically retains the stamp pattern without requiring additional processing steps, simplifying the overall process for large area substrates compared to conventional thixotropic embossing methods
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 sol-gel layer provides excellent temperature stability and flexibility, enabling the production of thick, crack-resistant, and optically transparent composites with enhanced mechanical and chemical resistance, suitable for various applications including optical uses.
Implementation Method 1
a stamp is pressed into a sol-gel layer and thermal crosslinking is then carried out
Implementation Method 2
A coating composition is applied to a substrate in order to obtain a sol-gel layer
Data Source
AI summary
The composite material comprises a substrate, and a structured sol-gel-layer, which comprises an elastic modulus of 200-10,000 N/mm 2>and a reaction product of an alkoxysilane having a polysiloxane comprising an average molecular weight of 1500-300,000 g/mole. The substrate is a glass ceramic, a glass, and a ceramic or a polymeric plastic. The structured sol-gel layer is: embossed; has an embossed structure having a depth of 2-200 Pm; and comprises a silicon dioxide content of 10-70 wt.%, an inorganic cross-linking degree of greater than 70%, and a beta -hydroxyl content of 0.01-100 mm. The composite material comprises a substrate, and a structured sol-gel-layer, which comprises an elastic modulus of 200-10,000 N/mm 2>and a reaction product of an alkoxysilane having a polysiloxane comprising an average molecular weight of 1500-300,000 g/mole. The substrate is a glass ceramic, a glass, and a ceramic or a polymeric plastic. The structured sol-gel layer is: embossed; has an embossed structure having a depth of 2-200 Pm; and comprises a silicon dioxide content of 10-70 wt.%, an inorganic cross-linking degree of greater than 70%, and a beta -hydroxyl content of 0.01-100 mm. The composite material is obtainable by a process in which a coating composition is applied to the substrate. An independent claim is included for a method for producing a composite material.