Scratch Resistant Film Composition for Low Bow Substrates
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Solution Overview
Problem
Coatings applied to glass-based substrates often exhibit residual stress, leading to substrate bow and deformation, which conventional technologies fail to adequately address while providing high scratch resistance.
Innovation Solution
A film with specific compositions of aluminum, nitrogen, and oxygen is deposited on a glass-based substrate, with tailored tensile and compressive stress components to achieve a residual stress range of -200 MPa to 200 MPa, reducing substrate bow and enhancing scratch resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If film thickness is increased to enhance scratch resistance, then hardness is improved, but residual stress increases causing substrate bow
Solution Approach 1:
The patent applies parameter changes by precisely controlling the oxygen concentration parameter in the film composition to achieve the desired residual stress state. By adjusting oxygen concentration to specific ranges (4-24 atomic%), the film achieves both high hardness and low residual stress, resolving the contradiction between scratch resistance and stress-induced substrate bow.
Solution Approach 2:
The patent uses composite materials by combining aluminum, nitrogen, and oxygen in specific proportions within the film layer. This composite approach allows the film to exhibit both high hardness (for scratch resistance) and controlled residual stress (to prevent substrate bow), achieving multiple performance targets simultaneously.
2Strength
If film thickness is increased to enhance scratch resistance, then hardness is improved, but substrate bow increases
Solution Approach 1:
The patent changes the chemical composition parameters of the film, specifically oxygen concentration, to control residual stress. This parameter adjustment allows thick films to provide high scratch resistance while maintaining low substrate bow by optimizing the stress state through compositional control.
3Strength
If conventional coating materials are used to provide scratch resistance, then hardness is improved, but residual stress exceeds acceptable limits
Solution Approach 1:
The patent fundamentally changes the material parameters by introducing oxygen as a key controlling element. By adjusting oxygen concentration to specific ranges, the film achieves both high hardness and controlled residual stress, overcoming the limitations of conventional coating materials that cannot simultaneously provide scratch resistance and stress control.
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 solution effectively reduces substrate bow and deformation while providing high hardness and transparency, achieving a balance between scratch resistance and low residual stress.
Implementation Method 1
A film is disposed on a surface of the substrate. The film includes an aluminum concentration of about 45 atomic % to about 50 atomic %, a nitrogen concentration of about 26 atomic % to about 46 atomic % and an oxygen concentration of from about 4 atomic % to about 24 atomic %.
Data Source
AI summary
An article is provided which includes a substrate and a film disposed on a surface of the substrate. The film includes an aluminum concentration of about 45 atomic % to about 50 atomic %, a nitrogen concentration of about 26 atomic % to about 46 atomic % and an oxygen concentration of from about 4 atomic % to about 24 atomic %. The substrate comprises a bow of less than about 0.0005 meters.