Nanostructured Pillars for OLED Color Uniformity
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Solution Overview
Problem
Existing optical applications, such as organic light emitting diode (OLED) displays, face challenges in maintaining color uniformity across different view angles due to variations in light output, which is not adequately addressed by current nanostructured surfaces.
Innovation Solution
A nanostructured article with a surface featuring a plurality of pillars, where the average height of the pillars is greater than their average lateral dimension, and an average center-to-center spacing of no more than 2000 nm, is used. The pillars have differing compositions in their lower and upper portions, with a refractive index difference between these portions ranging from 0.1 to 1.5, and a second layer extending continuously over the pillars, enhancing optical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a nanostructured surface with pillars is used to correct color in OLED displays, then color uniformity across view angles is improved, but the on-axis light output may be significantly altered
Solution Approach 1:
The patent applies local quality by creating pillars with different compositions in their lower and upper portions. The lower portion has a refractive index within 0.1 of the second layer to maintain on-axis light output, while the upper portion has a different composition to provide color correction for off-axis viewing angles. This gradient composition allows each region of the pillar to serve a specific optical function.
Solution Approach 2:
The patent utilizes parameter changes by carefully controlling the refractive index of the lower portion of the pillars to be within 0.1 of the second layer's refractive index. This specific parameter control ensures minimal impact on on-axis light output while the upper portion's different composition provides the necessary color correction for wide viewing angles.
2Reliability
If the average height of pillars is made greater than their lateral dimension to improve nanostructure effectiveness, then optical performance is enhanced, but manufacturing precision requirements increase
Solution Approach 1:
The patent specifies precise parameter ranges for pillar dimensions: average height of 280-510 nm, average lateral dimension of 160-220 nm, and center-to-center spacing of 310 nm or less. These controlled parameters ensure the aspect ratio (height greater than lateral dimension) is maintained while providing clear manufacturing targets for achieving reliable optical performance.
Solution Approach 2:
The patent differentiates the lower and upper portions of the pillars with different compositions, where the lower portion has specific refractive index requirements (within 0.1 of the second layer) and the upper portion has different composition. This local differentiation allows optimization of each region for its specific function while maintaining overall structural integrity.
3Illumination intensity
If the refractive index difference between lower portion and second layer is minimized to maintain on-axis light output, then on-axis brightness is preserved, but color correction capability for off-axis angles is reduced
Solution Approach 1:
The patent resolves this contradiction by assigning different optical properties to different regions of the pillar structure. The lower portion has refractive index within 0.1 of the second layer to preserve on-axis brightness, while the upper portion has different composition to provide color correction for off-axis viewing angles. This spatial differentiation of optical properties allows both requirements to be satisfied simultaneously.
Solution Approach 2:
The patent transitions from a uniform single-layer structure to a vertically stratified multi-composition structure. By adding the vertical dimension of compositional variation (lower portion vs. upper portion), the system can independently optimize for both on-axis brightness preservation and off-axis color correction without compromise.
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 nanostructured article provides improved color correction for OLED displays by maintaining consistent color output across various view angles without significantly altering on-axis light output, achieving reduced color variation and enhanced optical performance.
Implementation Method 1
The lower portion of the pillars has a first refractive index and the second layer has a second refractive index. An absolute value of a difference between the first and second refractive indices is in a range of 0.1 to 1.5.
Data Source
AI summary
A nanostructured article having a first layer with a nanostructured surface is described. The nanostructured surface includes a plurality of pillars extending from a base surface of the first layer. The pillars have an average height greater than an average lateral dimension of the pillars. An average center-to-center spacing between pillars is no more than 2000 nm. The average lateral dimension is no less than 50 nm. Each pillar in the plurality of pillars has at least a lower portion and an upper portion where the lower portion is between the upper portion and the base surface, and the upper and lower portions have differing compositions. The nanostructured article includes a second layer disposed over the plurality of pillars and extending continuously to the base surface.