Optical Adjustment Layer Refraction Index Control for Display Color Shift
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Solution Overview
Problem
Current organic EL display devices face challenges in achieving optimal resonance structures for light-emitting elements, leading to inefficient emission intensity and color purity, particularly due to limitations in material selection and layer thickness, which result in color shift phenomena and decreased display quality.
Innovation Solution
Incorporating an optical adjustment layer with varying refractive indices over the second electrode of light-emitting elements, allowing for controlled refraction index changes via light irradiation, which optimizes the optical length and resonance structure, thereby enhancing emission intensity and color purity across different pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single refraction index optical adjustment layer is used for all pixels, then the manufacturing process is simple, but the emission color and resonance structure cannot be optimized for different pixels
Solution Approach 1:
The patent applies local quality by making the refraction index of the optical adjustment layer pixel-dependent. Each pixel region (first pixel, second pixel, third pixel) has optical adjustment layers with different refraction indexes (n1, n2, n3) tailored to optimize the resonance structure and emission color for that specific pixel's light-emitting element, while still using a unified manufacturing process that forms the optical adjustment layer continuously across all pixels.
2Manufacturing precision
If the optical adjustment layer is formed individually for each pixel with different refraction indexes, then the emission color and resonance structure can be optimized, but the manufacturing process becomes complex
Solution Approach 1:
The patent merges the formation of optical adjustment layers for multiple pixels into a single continuous layer structure. The optical adjustment layer is formed as one continuous film that spans across the first pixel, second pixel, and third pixel, with different refraction indexes in different pixel regions. This unified approach simplifies the manufacturing process compared to forming separate optical adjustment layers for each pixel, while still achieving pixel-specific optical optimization.
3Ease of manufacture
If the refraction index of the optical adjustment layer is not adjusted, then the manufacturing process is straightforward, but color shift phenomena occur and display quality decreases
Solution Approach 1:
The patent applies parameter changes by varying the refraction index parameter of the optical adjustment layer material across different pixel regions. By selecting materials with different refraction indexes (n1, n2, n3) for different pixels, the resonance structure and emission characteristics are optimized for each pixel, preventing color shift phenomena and improving display quality and color accuracy.
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
This approach improves emission intensity and narrows the emission spectrum, reduces color shift, and enhances color reproducibility by allowing for precise control of resonance structures in light-emitting elements, leading to improved display quality and color accuracy.
Implementation Method 1
Emission color of a light-emitting element can also be adjusted by utilizing a light-interference effect in a light-emitting element
Implementation Method 2
A refraction index of the optical adjustment layer over the first light-emitting element is different from that of the optical adjustment layer over the second light-emitting element
Data Source
AI summary
Disclosed is a display device including: a substrate; and a first light-emitting element and a second light-emitting element over the substrate and adjacent to each other. The first light-emitting element and the second light-emitting element each possess a first electrode, an EL layer over the first electrode, a second electrode over the EL layer, and an optical adjustment layer over the second electrode. The optical adjustment layer over the first light-emitting element is different in refraction index from the optical adjustment layer over the second light-emitting element. A first material included in the optical adjustment layer may be the same in composition but different in chemical structure between before and after the light irradiation. Alternatively, the first material may be the same in composition but different in phase structure between before and after the light irradiation.