Multilayer Anti-Reflection Coating for Low-Glare Display Windows
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Solution Overview
Problem
Existing display devices face challenges in reducing external light reflectance and maintaining reliability and stability due to issues with light reflection and potential lifting of anti-reflection layers.
Innovation Solution
An anti-reflection layer comprising alternating high-refractive-index layers of niobium (Nb) and oxygen (O) and low-refractive-index layers of silicon (Si) and oxygen (O) with specific molar ratios and thicknesses, ensuring stable adhesion to the window layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single-layer anti-reflection coating is applied, then the manufacturing process is simple, but the light reflectance cannot be reduced below a certain level
Solution Approach 1:
The anti-reflection layer is divided into multiple sub-layers with different refractive indices (first anti-reflection sub-layer with low refractive index, second anti-reflection sub-layer with high refractive index). This segmentation allows each layer to contribute differently to light interference, achieving superior reflectance reduction that cannot be obtained with a single homogeneous layer.
Solution Approach 2:
The patent employs a composite structure combining materials with different optical properties - specifically, a low-refractive-index material (such as SiO2 or organic resin) and a high-refractive-index material (such as TiO2, Nb2O5, or Ta2O5). This composite multi-layer structure creates optimal optical interference conditions for minimizing reflection across the visible spectrum.
2Length of stationary object
If the anti-reflection layer is made thinner to reduce device thickness, then the overall device becomes more compact, but the anti-reflection effect and adhesion stability deteriorate
Solution Approach 1:
Different regions of the anti-reflection layer are assigned different thicknesses and material compositions optimized for their specific functions. The first sub-layer (low refractive index) has a thickness of 50-150 nm optimized for adhesion and initial light interference, while the second sub-layer (high refractive index) has a thickness of 100-250 nm optimized for maximum reflectance reduction. This local optimization allows the overall structure to be thin while maintaining both adhesion stability and anti-reflection performance.
Solution Approach 2:
The patent transitions from considering only the thickness dimension to optimizing multiple dimensions simultaneously - including layer composition, refractive index distribution, and thickness gradient. By controlling the refractive index contrast between layers and optimizing the thickness of each sub-layer independently, the patent achieves superior anti-reflection effect in a reduced overall thickness without compromising adhesion.
3Object-affected harmful factors
If high-refractive-index materials are used to improve anti-reflection effect, then light reflectance is reduced, but the adhesion between anti-reflection layer and window layer deteriorates
Solution Approach 1:
The anti-reflection layer is segmented into two functional sub-layers: the first sub-layer uses low-refractive-index materials (SiO2, organic resin) that provide excellent adhesion to the window layer, while the second sub-layer uses high-refractive-index materials (TiO2, Nb2O5, Ta2O5) that maximize light interference. This segmentation allows the adhesion function and anti-reflection function to be decoupled and optimized independently.
Solution Approach 2:
The first anti-reflection sub-layer acts as an intermediary between the window layer and the second anti-reflection sub-layer. It provides a transition zone with compatible mechanical and chemical properties that ensure strong adhesion to the window layer, while also serving as an optical interface that works in conjunction with the second layer to achieve minimal reflectance. This intermediary layer prevents direct contact between potentially incompatible materials.
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 anti-reflection layer effectively reduces external light reflectivity to less than 2% while preventing lifting, enhancing user convenience and increasing the reliability and stability of the display device.
Implementation Method 1
One of these attempts is to alternately arrange low-refractive-index layers and high-refractive-index layers on a product to reduce a reflectance for external light
Data Source
AI summary
A display device includes a light emitting diode disposed on a substrate, a window layer disposed on the light emitting diode, and an anti-reflection layer disposed on the window layer and including a plurality of high-refractive-index layers each including niobium (Nb) and oxygen (O), and a plurality of low-refractive-index layers each including silicon (Si) and oxygen (O). A molar ratio of niobium (Nb) to oxygen (O) included in each of the plurality of high-refractive-index layers is in a range of about 1 to about 2, and a molar ratio of silicon (Si) to oxygen (O) included in each of the plurality of low-refractive-index layers is in a range of about 0.3 to about 0.7.