Antireflective Coating Zirconium Oxide Scratch Resistance
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Solution Overview
Problem
Existing antireflective coatings suffer from low resistance to scratching and abrasion, leading to haze and a reversal of the antireflective effect due to wear on the soft silicon oxide layer.
Innovation Solution
A multilayered antireflective coating is developed with alternating layers of high and low refractive indices, where the low refractive index layers are composed of a silicon oxide and zirconium oxide mixture with a zirconium content of 0.2% to 10% by weight, enhancing scratch resistance without significantly altering the refractive index.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a low refractive index silicon oxide layer is used as the uppermost layer of the antireflective coating, then the antireflective effect is improved, but the scratch resistance and wear resistance deteriorate
Solution Approach 1:
The patent modifies the chemical composition of the silicon oxide layer by adding aluminum oxide (Al2O3) in controlled amounts (0.1-10 wt%). This parameter change increases the hardness and scratch resistance of the low refractive index layer while maintaining its optical properties and antireflective function.
Solution Approach 2:
The patent creates a composite material by combining silicon oxide with aluminum oxide to form an Al-doped SiO2 layer. This composite structure integrates the low refractive index property of SiO2 with the high hardness of Al2O3, simultaneously achieving both antireflective effect and scratch resistance.
2Reliability
If the uppermost layer is worn away, then the substrate is exposed, but the antireflective effect is lost and reflection increases
Solution Approach 1:
The patent applies a hardening agent (aluminum oxide) to the uppermost layer before it is exposed to wear conditions. This pre-treatment creates a scratch-resistant surface that prevents the layer from being worn away, thereby maintaining the antireflective effect throughout the service life of the coating.
Solution Approach 2:
By modifying the composition of the uppermost layer with aluminum oxide, the patent changes the physical parameters (hardness, wear resistance) of the layer to prevent degradation, ensuring long-term maintenance of the antireflective properties without loss of material.
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 coating achieves improved mechanical resistance and wear resistance, with a minimal change in reflectance, effectively maintaining the antireflective effect even under mechanical stress.
Implementation Method 1
Interference optical coatings are today often used as an antireflective coating
Implementation Method 2
The antireflective coating can be produced by means of a sputtering process
Data Source
AI summary
A coated substrate includes a substrate and a multilayered antireflective coating built up from layers having different refractive indices on at least one side of the substrate. Layers having a relatively high refractive index and layers having a relatively low refractive index alternate and at least one layer having a relatively low refractive index is composed of a composition X containing silicon oxide and zirconium oxide. A proportion of zirconium in a metallic and semiconducting component in the composition X is 0.2% to 10% by weight.