OLED Substrate Aperture Ratio via Local Quality
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Solution Overview
Problem
Traditional organic electroluminescence displays have a low aperture ratio due to the uniform size of red, green, and blue sub-pixels, which reduces the effective light-emitting area and increases the non-luminous regions, especially for sub-pixels with lower luminous efficiency, such as blue, leading to reduced service life and brightness matching issues.
Innovation Solution
The organic electroluminescence array substrate is designed with varying sub-pixel dimensions, where the width of the red and green sub-pixels is less than the blue sub-pixel, and their effective light-emitting areas are adjusted based on luminous efficiency ratios to maximize the aperture ratio by increasing the blue sub-pixel area and reducing the red and green sub-pixel areas, ensuring uniform brightness and extended service life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the effective light-emitting area of blue sub-pixel is increased to match brightness with red and green sub-pixels, then the service life of blue sub-pixel is reduced, but the aperture ratio of red and green sub-pixels is reduced
Solution Approach 1:
The patent applies local quality by assigning different areas to different colored sub-pixels based on their specific luminous efficiency characteristics. Blue sub-pixels are given a larger area to compensate for their lower luminous efficiency, while red and green sub-pixels have smaller areas matching their higher efficiency. This localized differentiation resolves the contradiction by optimizing each sub-pixel's contribution to overall display brightness without uniformly reducing all sub-pixel areas.
Solution Approach 2:
The patent changes the area parameter of sub-pixels according to their luminous efficiency characteristics. By establishing area ratios that correspond to the inverse of luminous efficiency ratios (blue: red: green = 1: 2: 2 or similar variations), the patent adjusts the physical dimensions of sub-pixels to achieve balanced brightness output. This parameter change allows blue sub-pixels to emit sufficient light without requiring excessive current, thereby preserving service life while maintaining overall aperture ratio.
2Ease of manufacture
If uniform size is assigned to all sub-pixels for simplicity, then the manufacturing process is simplified, but the effective light-emitting area is reduced and non-luminous regions increase
Solution Approach 1:
The patent implements local quality by differentiating sub-pixel areas according to their color and luminous efficiency properties. Instead of uniform sizing, each sub-pixel type (red, green, blue) is assigned a specific area ratio that optimizes its light output. This approach maintains manufacturing feasibility while significantly improving the effective light-emitting area by eliminating wasted non-luminous regions that would result from uniform sizing.
3Illumination intensity
If current is increased to blue sub-pixel to match brightness with red and green sub-pixels, then the brightness matching is achieved, but the service life of the display is reduced
Solution Approach 1:
The patent changes the area parameter of blue sub-pixels to compensate for their lower luminous efficiency. By increasing the area of blue sub-pixels relative to red and green sub-pixels (establishing area ratios such as blue: red: green = 1: 2: 2 or blue: red: green = 1: 1.5: 1.5), the patent achieves balanced brightness output without requiring increased current. This parameter change directly addresses the contradiction by maintaining brightness while preserving service life through reduced electrical stress on blue sub-pixels.
Data Source
Figure 1
Figure 2~3
AI summary
An organic electroluminescence array substrate, a manufacturing method thereof and a display device are provided, and the organic electroluminescence array substrate comprises an active backplane (100) and a color display layer formed on the active backplane (100), wherein the color display layer includes a plurality of pixel units (107, 108, 109); and each pixel unit (107, 108, 109) includes a red sub-pixel (107), a green sub-pixel (108) and a blue sub-pixel (109). Both an area of the red sub-pixel (107) and an area of the green sub-pixel (108) are less than an area of the blue sub-pixel (109). The organic electroluminescence array substrate has increased aperture ratio thereof.