OLED Pixel Electrode Layout for Defective Pixel Isolation
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Solution Overview
Problem
In electroluminescence display devices, defective pixels caused by short circuits or transistor malfunctions lead to increased power consumption and image quality degradation, as these devices rely on continuous current flow, making it difficult to correct and isolate affected pixels without affecting others.
Innovation Solution
The method involves cutting off the connection between a defective pixel's electrode and the power supply line, either by physically severing the wire or keeping the transistor connected to the pixel off, using techniques like laser irradiation to prevent current flow and thus prevent the pixel from emitting light, and reducing wire widths to minimize impact on adjacent pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the thickness of the electroluminescent layer is reduced to decrease power consumption and improve response speed, then power consumption decreases and response speed improves, but short circuit between electrodes occurs more easily
Solution Approach 1:
The patent introduces an auxiliary electrode structure nested within the pixel electrode, creating a multi-layered electrical connection system. The auxiliary electrode is positioned between the pixel electrode and the electroluminescent layer, forming a nested configuration that provides redundant current paths while maintaining thin electroluminescent layer thickness.
Solution Approach 2:
The auxiliary electrode acts as an intermediary element between the pixel electrode and the electroluminescent layer. It mediates the current flow by providing an additional conductive path that reduces the risk of short circuits while enabling the use of thinner electroluminescent layers for lower power consumption.
2Productivity
If a defective pixel is not corrected, then production yield decreases, but correcting it by cutting wires or keeping transistors off may affect adjacent pixels
Solution Approach 1:
The patent applies local quality by making the auxiliary electrode connection selective and localized. The auxiliary electrode is connected to the pixel electrode only in specific regions, allowing defective pixels to be corrected by controlling the auxiliary electrode while leaving adjacent pixels unaffected. This localized approach enables precise defect correction without propagating issues to neighboring pixels.
Solution Approach 2:
The patent segments the current path by introducing a separate auxiliary electrode system that is distinct from the main pixel electrode structure. This segmentation allows independent control of current flow to defective pixels through the auxiliary electrode, enabling correction of defective pixels without affecting the integrity or operation of adjacent pixels.
3Object-affected harmful factors
If the wire width is reduced to minimize impact on adjacent pixels, then isolation of defective pixels improves, but manufacturing precision requirements increase
Solution Approach 1:
The patent employs dynamics by making the auxiliary electrode width variable rather than uniform. The auxiliary electrode has different widths in different regions: narrower widths in areas where isolation is critical to minimize impact on adjacent pixels, and wider widths in areas where robust connection is needed. This dynamic width variation optimizes both isolation and manufacturing feasibility.
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 corrects defective pixels, reduces power consumption, and enhances overall image quality by preventing bright spots and minimizing screen degradation, while also increasing production yield and reducing costs.
Implementation Method 1
at least a part of a wire between one electrode of a light emitting element and a power supply line for applying a potential to the one electrode of the light emitting element is cut off
Implementation Method 2
using techniques like laser irradiation to prevent current flow
Data Source
AI summary
In view of the problem that a reduced thickness of an EL film causes a short circuit between an anode and a cathode and malfunction of a transistor, the invention provides a display device that has a light emitting element including an electrode and an electroluminescent layer, a wire electrically connected to the electrode of the light emitting element, a transistor provided with an active layer including a source, a drain and a channel forming region, and a power supply line electrically connected to one of the source and the drain of the transistor, wherein the wire is electrically connected to the other of the source and the drain of the transistor, and the width of a part of the electrode in the vicinity of a portion where the electrode is electrically connected to the wire is smaller than that of the electrode in the other portion.