OLED Sub-pixel Insulation Layer for Leakage Current Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The decrease in distance between adjacent sub-pixels in organic light-emitting diode display devices leads to lateral leakage currents, which reduces color reproducibility by causing unwanted sub-pixels to emit light, particularly at low gray levels.
Innovation Solution
The implementation of an organic light-emitting diode display device with an interlayer insulation layer of varying heights between sub-pixels, where the second electrode of one light-emitting diode is electrically connected to the charge generation layer of another, and the trench is formed between sub-pixels of different colors to minimize lateral leakage currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the distance between adjacent sub-pixels is decreased to achieve high resolution, then the display resolution is improved, but lateral leakage current occurs between sub-pixels causing poor color reproducibility
Solution Approach 1:
The charge generation layer is divided into multiple independent regions, with each region corresponding to a specific sub-pixel. This segmentation prevents charge carriers from migrating laterally between adjacent sub-pixels, thereby eliminating leakage current while maintaining high resolution display capabilities
Solution Approach 2:
Different regions of the charge generation layer are assigned different properties - each region is selectively connected to specific electrodes (anode or cathode) based on the requirements of the corresponding sub-pixel. This local differentiation ensures that charge generation occurs only in the intended sub-pixel regions, preventing lateral leakage
2Measurement precision
If the area of each sub-pixel is reduced to increase the number of sub-pixels, then the display resolution is improved, but the aperture ratio decreases
Solution Approach 1:
The patent introduces a vertical dimension to the electrode structure by creating a three-dimensional electrode configuration. This allows the light-emitting layer to be positioned closer to the substrate, effectively increasing the aperture ratio without requiring larger sub-pixel areas, thus maintaining high resolution while improving light emission efficiency
3Measurement precision
If the distance between sub-pixels is decreased, then the display resolution is improved, but color purity at low gray levels deteriorates due to lateral leakage current
Solution Approach 1:
The charge generation layer is segmented into discrete regions aligned with individual sub-pixels, preventing lateral migration of charge carriers. This segmentation maintains color purity at low gray levels by ensuring that only the intended sub-pixel emits light, even when sub-pixel distances are reduced for high resolution
Solution Approach 2:
The segmented charge generation layer acts as an intermediary between the electrodes and the light-emitting layer, controlling charge carrier generation and transport. This intermediary structure prevents lateral leakage current while maintaining efficient charge injection into the light-emitting layer, thereby preserving color purity
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 configuration effectively minimizes lateral leakage currents, improves color purity at low gray levels, and enhances color reproducibility by ensuring that only intended sub-pixels emit light, thereby increasing the aperture ratio and efficiency of the display.
Implementation Method 1
organic light-emitting diode display devices, which are also referred to as organic electroluminescent display devices, emit light due to the radiative recombination of an exciton. The exciton is formed from an electron and a hole by injecting charges into a light-emitting layer
Data Source
AI summary
An organic light-emitting diode display device can include a substrate including a first sub-pixel and a second sub-pixel; an interlayer insulation layer over the substrate and having different heights; and a first light-emitting diode disposed at the first sub-pixel and a second light-emitting diode disposed at the second sub-pixel over the substrate, wherein each of the first light-emitting diode or second light-emitting diode includes a first electrode, a light-emitting layer, and a second electrode, and the light-emitting layer includes a first stack, a charge generation layer, and a second stack, and wherein the second electrode of the first light-emitting diode is electrically connected to the charge generation layer of the first light-emitting diode, and the second electrode of the second light-emitting diode is separated from the charge generation layer of the second light-emitting diode.