Dummy Pixel Electrode for Leakage Current Suppression
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Solution Overview
Problem
In ultra-fine pixel structures of display devices, such as micro OLEDs and micro LEDs, leakage currents through side surfaces between adjacent pixels cause color interference and deteriorate image quality, particularly due to the small width of banks between pixels.
Innovation Solution
A display device configuration that includes a dummy pixel electrode receiving a dummy voltage, which is different from the pixel voltage, to consume lateral leakage currents without using a physical separator, thereby preventing color mixing and improving image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a physical separator structure is used to block leakage current, then leakage current between adjacent pixels is blocked, but voids are generated under the separator which may damage the encapsulation film
Solution Approach 1:
The patent replaces the mechanical/physical separator structure with an electrical field-based solution. By applying a specific voltage to the dummy pixel electrode, an electrical field is created that repels leakage current away from the bank region, thereby blocking the harmful current without any physical structure that could create voids or damage the encapsulation film.
Solution Approach 2:
The dummy pixel electrode serves as an intermediary element between the adjacent pixel electrodes. It creates an intermediate electrical field that acts as a barrier to leakage current, preventing the current from crossing the bank region while avoiding the structural problems associated with physical separators.
2Productivity
If the bank width is reduced to achieve ultra-fine pixel structure, then pixel density is increased, but leakage current through side surfaces increases causing color interference
Solution Approach 1:
The patent applies a localized electrical field control strategy by applying voltage only to the dummy pixel electrode positioned between adjacent pixels. This creates a localized potential barrier precisely where leakage current occurs (at the bank region), allowing ultra-fine pixel structures to maintain low leakage current without affecting the overall pixel density.
Solution Approach 2:
The dummy pixel electrode is configured in advance to create a repulsive electrical field that prevents leakage current from occurring in the first place. By establishing this protective electrical field before leakage current can develop, the patent enables ultra-fine pixel structures to operate without color interference despite the reduced bank width.
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
The use of a dummy pixel electrode with a specific configuration and voltage effectively suppresses lateral leakage currents, enhancing image quality by preventing color interference between adjacent pixels without the issues associated with physical separators, such as void formation and encapsulation film damage.
Implementation Method 1
a dummy pixel electrode between the first pixel electrode and the second pixel electrode, and configured to receive a dummy voltage
Implementation Method 2
leakage currents through side surfaces via common layers, such as a hole transporting layer and an electron transporting layer
Data Source
AI summary
A display device includes: a substrate; a first pixel electrode and a second pixel electrode on the substrate; a dummy pixel electrode between the first pixel electrode and the second pixel electrode, and to receive a dummy voltage; an emissive layer on the first pixel electrode, the second pixel electrode, and the dummy pixel electrode; and a common electrode on the emissive layer. The first pixel electrode is to receive a pixel voltage different from the dummy voltage.