OLED Pixel P-Doped Layer Segmentation for Leakage Current Control
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Solution Overview
Problem
Organic light emitting diode displays face issues with lateral leakage current due to the intermediate p-doped layer acting as a path for electric charge movement, leading to improper color implementation and color-mixing, especially when displaying grays at low luminance.
Innovation Solution
The intermediate p-doped layer is differentially applied to each pixel without forming it as a common layer, and second doped layers are spaced apart on the pixel electrodes to prevent leakage current, allowing for high luminous efficiency and smooth gray display at low voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If an intermediate p-doped layer is formed as a common layer to improve charge mobility and reduce driving voltage, then low-voltage driving and high luminous efficiency are achieved, but lateral leakage current occurs causing color-mixing and improper color display
Solution Approach 1:
The intermediate p-doped layer is segmented into pixel-specific layers rather than forming a continuous common layer. Each pixel electrode has its own intermediate p-doped layer that is electrically isolated from adjacent pixels, preventing lateral leakage current while maintaining the charge mobility benefits in each pixel region.
Solution Approach 2:
The intermediate p-doped layer is applied locally to each pixel electrode rather than uniformly across the entire display. This local application ensures that the high charge mobility benefit is provided where needed (at each pixel electrode interface) while preventing the formation of lateral leakage paths between pixels.
2Productivity
If an intermediate p-doped layer is formed as a common layer to improve charge mobility, then high luminous efficiency is achieved, but leakage current causes smooth gray display to be impossible at low luminance
Solution Approach 1:
By segmenting the intermediate p-doped layer into discrete pixel-specific layers, the invention prevents lateral leakage current that would otherwise cause gray level non-uniformity. Each pixel's intermediate layer is independently controlled, enabling precise gray level display across the entire display.
3Reliability
If second doped layers are spaced apart on pixel electrodes to prevent leakage current, then color accuracy is improved, but device complexity increases
Solution Approach 1:
The invention merges the functions of the intermediate p-doped layer and the pixel-specific doped layers into a unified structure. By forming pixel-specific intermediate p-doped layers that serve both as charge mobility enhancement layers and as leakage prevention barriers, the device complexity is minimized while achieving the desired color accuracy.
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 effectively prevents leakage current and enhances luminous efficiency by ensuring uniform light emission across all pixel colors, enabling smooth gray display without color-mixing.
Implementation Method 1
an interface p-doped layer 41, a hole transporting layer 42, an intermediate p-doped layer 43
Implementation Method 2
organic light emitting diode displays are self-luminous display devices that use organic light emitting diodes to emit light
Data Source
AI summary
An organic light emitting diode display includes a p-doped layer that can obtain high efficiency at low-voltage driving and low current and prevent leakage current by differentially forming the p-doped layer for each pixel.