OLED Sub-Pixel Electrode Area Optimization for High Resolution
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Solution Overview
Problem
Current OLED display technologies face limitations in achieving high resolution due to the low luminous efficiency of blue sub-pixels and the difficulty in reducing the area of red and green sub-pixels using the FMM evaporating process, which results in increased costs and reduced display luminance.
Innovation Solution
The OLED array substrate and fabricating method involve forming organic luminescent material layers of different colors to cover adjacent pixel electrodes, allowing for a high-resolution display by reducing the area of pixel electrodes and optimizing the coverage area of the mask plate during the evaporating process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high fine metal mask plate (FMM) is used to plate organic light emitting materials of different primary colors to form respective pixels, then the display resolution can be improved, but the area of the pixel becomes smaller and the process difficulty increases significantly
Solution Approach 1:
The patent divides the pixel structure into multiple layers: a base layer with pixel electrodes arranged in a matrix, and organic luminescent material layers deposited on top. Each pixel electrode corresponds to a sub-pixel, and the organic material layers are segmented by color (red, green, blue) and positioned on specific pixel electrodes. This segmentation allows independent control and optimization of each color channel while maintaining high resolution.
Solution Approach 2:
The patent transitions from a two-dimensional mask plate approach to a three-dimensional layered structure. Instead of using a single FMM layer to define all pixel patterns, the invention uses multiple layers: the pixel electrode layer defines the sub-pixel positions, and subsequent organic material layers are deposited in specific patterns on top. This dimensional transition allows the mask plate to have larger hollowed areas while still achieving high resolution through the underlying pixel electrode arrangement.
2Use of energy by moving object
If the area of the blue sub-pixel is increased to compensate for low luminous efficiency, then the luminous efficiency can be improved, but the areas of the red and green sub-pixels must be reduced
Solution Approach 1:
The patent applies different properties to different parts of the display structure. Specifically, pixel electrodes intended for blue sub-pixels are given larger areas to compensate for the inherently lower luminous efficiency of blue organic materials. In contrast, pixel electrodes for red and green sub-pixels maintain smaller areas. This local differentiation allows each color channel to be optimized independently for its specific luminous characteristics.
Solution Approach 2:
The patent changes the area parameter of pixel electrodes based on the luminous efficiency requirements of different colors. By adjusting the area of pixel electrodes (and consequently the overlying organic material layers) according to the specific luminous properties of red, green, and blue materials, the overall display luminance and efficiency are optimized without requiring uniform pixel areas.
3Measurement precision
If the area of the pixel electrode is reduced to increase display resolution, then the display resolution can be improved, but the manufacturing cost increases due to FMM process limitations
Solution Approach 1:
The patent performs preliminary patterning of the pixel electrodes before depositing the organic luminescent materials. The pixel electrodes are formed with precise patterns and positions in advance, establishing the sub-pixel layout. This preliminary action allows the subsequent organic material deposition to follow a predetermined pattern, reducing the complexity and cost of the FMM process while maintaining high resolution.
Solution Approach 2:
The patent introduces the pixel electrode layer as an intermediary structure between the substrate and the organic luminescent material layers. This intermediary layer serves multiple functions: it defines the sub-pixel positions and boundaries, provides electrical connections, and acts as a template for the organic material deposition. By using this intermediary, the direct requirements on the FMM process are reduced, lowering manufacturing costs.
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 enables the fabrication of high-resolution OLED displays by effectively reducing the area of sub-pixels, improving display luminance, and reducing manufacturing costs while maintaining high evaporating accuracy.
Implementation Method 1
at least two organic luminescent material layers which display different colors are formed on the pixel electrode
Data Source
AI summary
An OLED array substrate, comprising a plurality of pixel units, the pixel unit at least comprising a first sub-pixel, a second sub-pixel and a third sub-pixel, further comprising: a substrate, a TFT array and a pixel electrode formed on the substrate, and at least two organic luminescent material layers that display different colors formed on the pixel electrode, wherein the first sub-pixel comprises a first pixel electrode, the second sub-pixel comprises a second pixel electrode, the third sub-pixel comprises a third pixel electrode, an organic luminescent material layer of a first color covers the adjacent first pixel electrode and second pixel electrode in the pixel unit, an organic luminescent material layer of a second color covers the adjacent second pixel electrode and third pixel electrode in the pixel unit.