Organic EL Display Divided Upper Electrode Voltage Loss
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Organic electroluminescent display devices face challenges in maintaining constant electric current and image quality, particularly on large screens, due to voltage decreases at the end pixels and material deterioration during the formation of organic EL films.
Innovation Solution
The upper electrode is divided into units of pixels or dots using an insulating partition, which reduces voltage loss and allows for individual power supply to each organic EL element, improving aperture ratio and reducing parasitic capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the upper electrode is formed as a common electrode over the entire substrate surface, then the device structure is simple and manufacturing is easy, but voltage decreases significantly at end pixels causing poor display uniformity
Solution Approach 1:
The upper electrode is divided into multiple independent electrode regions corresponding to different pixel rows or columns, separated by insulating partitions. This segmentation prevents voltage loss at end pixels by isolating each electrode region electrically, thereby improving display uniformity while maintaining manufacturing simplicity through a systematic division approach.
2Manufacturing precision
If the upper electrode is divided into units of pixels or dots using insulating partitions, then display uniformity improves and parasitic capacitance reduces, but device structure becomes more complex
Solution Approach 1:
The upper electrode is divided into multiple independent electrode regions corresponding to different pixel rows or columns, separated by insulating partitions. This segmentation prevents voltage loss at end pixels by isolating each electrode region electrically, thereby improving display uniformity while maintaining manufacturing simplicity through a systematic division approach.
Solution Approach 2:
Insulating partitions are introduced as intermediary structures between adjacent upper electrode regions. These partitions serve as electrical isolators that prevent parasitic capacitance formation while maintaining physical separation, thus improving display uniformity without requiring complex reconfiguration of the overall device architecture.
3Ease of operation
If the lower electrode (anode) is connected to the source electrode of the driving TFT, then the organic EL element is properly driven, but resistance changes in the organic EL film cause gate voltage changes making constant current driving difficult
Solution Approach 1:
The patent inverts the conventional connection configuration by connecting the lower electrode (anode) to the drain electrode instead of the source electrode of the driving TFT. This inversion compensates for resistance changes in the organic EL film, enabling more stable gate voltage control and improving constant current driving capability.
Data Source
AI summary
An organic electroluminescent display device is capable of flowing a constant electric current into each pixel and improving image qualities even if the device displays an image on a large screen. The organic electroluminescent display device including a lower electrode, an organic electroluminescent film, and an upper electrode on a substrate arranged in this order, wherein the upper electrode is divided in units of a pixel or dot by a partition having an insulating property.