Electroluminescent Display Air Gap Pixel Isolation
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Solution Overview
Problem
Electroluminescent display devices face issues with low light extraction efficiency and current leakage due to high conductivity of carrier generation layers, leading to color mixing and degraded image quality.
Innovation Solution
The device incorporates air gaps and insulating patterns to separate pixel regions, with a carrier generation layer and light-emitting layers structured to prevent current leakage and enhance light extraction efficiency, using a two-stack or three-stack light-emitting layer structure with a carrier generation layer between the layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a carrier generation layer with high conductivity is used to generate carriers efficiently, then carrier generation efficiency is improved, but current leakage increases and adjacent pixels are turned on simultaneously causing color mixing
Solution Approach 1:
The patent divides the carrier generation layer into separate regions corresponding to different pixel regions. Insulating patterns are introduced to segment the continuous conductive layer, creating electrically isolated zones that prevent current leakage between adjacent pixels while maintaining carrier generation efficiency within each pixel region.
Solution Approach 2:
The patent applies different properties to different parts of the device: the carrier generation layer has high conductivity within each pixel region for efficient carrier generation, while insulating patterns are placed at specific locations (between pixels) to block current leakage. This local differentiation of conductivity properties resolves the contradiction between efficiency and reliability.
2Illumination intensity
If light-emitting layers are used to emit light, then light emission is achieved, but light extraction efficiency is low due to total internal reflection at interfaces
Solution Approach 1:
The patent introduces an air gap as an intermediary layer between the light-emitting portion and the encapsulation layer. This air gap acts as an optical mediator that reduces the refractive index difference at interfaces, thereby reducing total internal reflection and improving light extraction efficiency without affecting the light emission process.
3Manufacturing precision
If pixel regions are closely packed to increase display resolution, then pixel density is improved, but color mixing occurs due to current leakage and light diffusion between adjacent pixels
Solution Approach 1:
The patent uses insulating patterns to segment and electrically isolate adjacent pixel regions. These insulating barriers prevent current leakage between pixels, ensuring that each pixel can be controlled independently even when closely packed, thereby preventing color mixing while maintaining high pixel density.
Solution Approach 2:
The patent extracts or removes the harmful conductive path between adjacent pixels by introducing insulating patterns. This extraction of the unwanted current leakage path allows pixel regions to be closely packed without causing color mixing, as the insulating barriers eliminate the harmful electrical connection between neighboring pixels.
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 improves light extraction efficiency and reduces current leakage, preventing color mixing and maintaining image quality by isolating pixel regions and optimizing light emission paths.
Implementation Method 1
an air gap over the substrate and configured to separate the plurality of pixel regions
Implementation Method 2
an electroluminescent display device is a device in which electrical charge carriers are injected into a light-emitting layer formed between a cathode, which is an electron-injecting electrode, and an anode, which is a hole-injecting electrode, such that excitons are formed. Then, radiative recombination of the excitons occurs, thereby emitting light.
Data Source
AI summary
An electroluminescent display device includes a substrate including a plurality of pixel regions; an air gap over the substrate and configured to separate the plurality of pixel regions; a first electrode in each of the plurality of pixel regions; an insulating pattern covering an edge of the first electrode; a light emitting portion on the first electrode and the insulating pattern; and a second electrode on the light emitting portion.