Optical Element Antireflection Coating with Stress Compensation
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Solution Overview
Problem
Existing antireflection films suffer from low adhesion between layers, leading to peeling and poor mechanical strength and environmental durability, particularly in optical elements with fluorine-containing organic compounds.
Innovation Solution
A multilayer antireflection film structure comprising magnesium fluoride, silicon oxide, and a fluorine-containing organic compound, with specific refractive index and thickness ratios, is used to enhance adhesion and durability, incorporating compressive stress to counteract tensile stress in the magnesium fluoride layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple antireflection film structure is used, then manufacturing complexity is reduced, but adhesion between layers deteriorates causing peeling
Solution Approach 1:
The antireflection film is divided into multiple layers with specific functions: a base layer, an intermediate layer containing silicon oxide and aluminum oxide, and an outer layer with fluorine-containing organic compound. This segmentation allows each layer to contribute to overall performance while maintaining strong interlayer adhesion through controlled stress distribution.
Solution Approach 2:
The patent employs composite material structures combining different materials (silicon oxide, aluminum oxide, fluorine-containing organic compounds) in specific layer configurations. These composite structures provide both mechanical strength through interlayer adhesion and optical performance through refractive index management.
2Illumination intensity
If magnesium fluoride layer is used for antireflection, then optical performance is improved, but tensile stress increases causing film peeling
Solution Approach 1:
The patent introduces an intermediate layer containing silicon oxide and aluminum oxide that generates compressive stress to counterbalance the tensile stress of the magnesium fluoride layer. This stress compensation prevents film peeling while maintaining the optical benefits of the magnesium fluoride antireflection layer.
Solution Approach 2:
The patent modifies the stress state of the film system by changing material composition and layer thickness parameters. Specifically, adjusting the ratio of silicon oxide to aluminum oxide and controlling layer thicknesses allows optimization of stress distribution to prevent peeling.
3Object-affected harmful factors
If fluorine-containing organic compound is applied for antifouling, then antifouling performance is improved, but adhesion to underlying layers deteriorates
Solution Approach 1:
The patent introduces an intermediate layer containing silicon oxide and aluminum oxide that serves as a mediator between the base layer and the fluorine-containing organic compound outer layer. This intermediate layer provides both mechanical support and chemical bonding interfaces, ensuring strong adhesion of the antifouling layer while maintaining its low surface energy properties.
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 multilayer film structure improves adhesion, abrasion resistance, and antireflection performance while maintaining mechanical strength and environmental durability, preventing cracking and peeling under various conditions.
Implementation Method 1
the compressive stress of the silicon oxide layer and the aluminum oxide layer counterbalances the tensile stress of the magnesium fluoride layer, thereby improving adhesion between the layers
Implementation Method 2
a first film (multilayer film) and a second film (multilayer film) are formed on the substrate in order from the substrate
Data Source
AI summary
An optical element includes a substrate and an antireflection film. The antireflection film comprises a first film formed on the substrate and a second film formed on the first film. The second film comprises a first layer, a second layer, and a third layer arranged consecutively in order from a side closer to the first film. The first layer includes magnesium fluoride. The second layer includes silicon oxide and aluminum oxide. The third layer includes a fluorine-containing organic compound.