ALD Optical Coatings for Uniform 3D Substrates
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Solution Overview
Problem
Challenges exist in producing uniform optical coatings on three-dimensional substrates, leading to non-uniform optical and mechanical properties due to variations in thickness across the surface, which are unacceptable for electronic products.
Innovation Solution
The use of atomic layer deposition (ALD) to apply optical coatings on non-planar substrates, ensuring uniformity of less than 10% physical thickness variation and maintaining single side light reflectance below 1% at wavelengths between 500 nm and 800 nm, with a hardness of at least 7 GPa, using alternating layers of high and low refractive index materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional coating methods are used on 3D substrates, then the coating process is simple and fast, but the coating thickness becomes non-uniform across the surface
Solution Approach 1:
The patent segments the coating process into multiple sequential atomic layer deposition cycles, where each cycle deposits a monolayer of material. This segmentation allows precise control over coating thickness at each stage, ensuring uniformity across complex 3D surfaces while maintaining processability through automated sequencing of deposition steps.
Solution Approach 2:
The patent changes the deposition parameters by using atomic layer deposition with controlled precursor exposure times and temperatures. By adjusting the number of deposition cycles and controlling the reaction conditions, the method achieves uniform coating thickness on 3D substrates with varying surface geometries, resolving the contradiction between precision and process complexity.
2Manufacturing precision
If the optical coating thickness varies across the 3D substrate surface, then the coating can be applied quickly, but the optical properties become non-uniform
Solution Approach 1:
The patent implements continuous atomic layer deposition cycles that uniformly coat the entire 3D substrate surface without interruption. The continuous process ensures that all surfaces receive equivalent deposition conditions, achieving uniform optical properties while maintaining productivity through uninterrupted coating operation and automated substrate handling.
3Manufacturing precision
If multiple coating layers are deposited to achieve uniformity, then the coating quality improves, but the manufacturing time increases
Solution Approach 1:
The patent uses periodic alternating deposition cycles between different materials (e.g., high refractive index and low refractive index layers). This periodic action creates a multi-layer structure that achieves superior optical uniformity and performance while the automated cycling minimizes idle time between deposition steps, balancing quality improvement with manufacturing efficiency.
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
Achieves uniform optical and mechanical properties across complex 3D surfaces, providing excellent hardness and consistent reflectance, addressing the challenges of non-planar substrates.
Implementation Method 1
The use of atomic layer deposition (ALD) to apply optical coatings on non-planar substrates
Implementation Method 2
the coated article at the first and second portions has a first single side light reflectance and a second single side light reflectance, respectively, as measured from the outer surface of the optical coating at an incident angle of 5 degrees
Data Source
AI summary
A coated article, comprising: a substrate having a major surface, the major surface comprising a first portion and a second portion, wherein a first axis that is normal to the first portion of the major surface is not equal to a second axis that is normal to the second portion of the major surface, and the angle between the first axis and the second axis is at least 40 degrees; and an optical coating disposed on at least the first portion and the second portion of the major surface; wherein the optical coating at the first and second portions has at least one of: a physical thickness uniformity of less than 10%, single side light reflectances of less than 1% at all wavelengths between 500 nm and 800 nm; and a hardness of at least 7 GPa at indentation depths of 50-250 nm.