OLED Overlapped Area Layout for Brightness Uniformity
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Solution Overview
Problem
The insufficient aperture ratio in the cathode overlapped area of organic light emitting devices leads to uneven brightness in high-resolution OLED displays due to disordered layouts.
Innovation Solution
An organic light emitting device with a specific layout in the overlapped area, featuring a first electrode, a pixel definition layer with blocks, an isolation layer with supporting blocks, and a second electrode, where the vertical projection positions of the blocks and openings are aligned, and the blocks are made from organic materials, enhancing the aperture ratio and reducing voltage drops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the overlapped area layout is disordered or inconsistent, then the device complexity is reduced, but the aperture ratio decreases and brightness uniformity deteriorates
Solution Approach 1:
The patent applies local quality by implementing a specific regular pattern only in the overlapped area (where wires and displays overlap) while other areas can have different layouts. The overlapped area uses pixel definition blocks and supporting blocks arranged in a consistent pattern with specific vertical projection alignment, while the non-overlapped areas maintain their existing layout designs, thus improving aperture ratio locally without requiring complete redesign of the entire device.
Solution Approach 2:
The overlapped area is segmented into discrete pixel definition blocks and supporting blocks with specific geometric arrangements. This segmentation allows each block to be independently optimized for aperture ratio while maintaining overall layout regularity. The pixel definition blocks define individual pixel regions and the supporting blocks provide structural support, both arranged in a segmented manner that improves light emission uniformity.
2Ease of manufacture
If the overlapped area layout is disordered or inconsistent, then the manufacturing process is simplified, but the brightness uniformity deteriorates
Solution Approach 1:
The patent implements local quality by applying a specific regular pattern only in the overlapped area where brightness uniformity issues occur, while leaving other manufacturing processes unchanged. The pixel definition blocks and supporting blocks in the overlapped area follow a consistent vertical projection alignment rule, ensuring uniform brightness in this critical region without complicating the manufacturing of other display areas.
3Area of stationary object
If the aperture ratio in the overlapped area is increased, then the brightness uniformity is improved, but the shielding effect increases
Solution Approach 1:
The patent resolves the shielding issue by transitioning to a transparent electrode structure in the overlapped area. Instead of using opaque metal electrodes that cause shielding, the invention employs transparent conductive materials that allow light to pass through while still providing electrical connectivity. This dimensional change from opaque to transparent resolves the harmful shielding effect while maintaining the increased aperture ratio benefits.
Data Source
AI summary
An organic light emitting device having an overlapped area located at an edge of a non-display area. The organic light emitting device includes: a first electrode, a pixel definition layer, an isolation layer and a second electrode. The first electrode is arranged on a planarization layer of the overlapped area. The pixel definition layer is arranged on the first electrode, and further includes a number of pixel definition blocks. The isolation layer is arranged on the pixel definition layer, and further includes a number of supporting blocks arranged in a manner same to that of the number of pixel definition blocks of the pixel definition layer. The second electrode covers the first electrode, the pixel definition blocks, and the supporting blocks in the overlapped area. the second electrode overlaps the first electrode.