OLED Pixel Redundancy via Segmented Anodes for Short Circuit Resistance
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Solution Overview
Problem
Conventional organic electroluminescent (EL) display devices are prone to short circuits between the anode and cathode, leading to dark pixels due to fine particles or external pressure, which results in unnoticeable pixel defects as the driving current flows to the cathode instead of the organic emission layer.
Innovation Solution
The implementation of at least two driving transistors and an organic light emitting diode with two first electrodes and a common second electrode per pixel, allowing the device to continue emitting light even if a short circuit occurs between one of the first electrodes and the second electrode, thereby minimizing the effect of the short circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single anode and cathode are used per pixel, then the device structure is simple, but short circuits between electrodes cause dark pixels and reduce reliability
Solution Approach 1:
The anode is divided into multiple segments (first anode and second anode) within each pixel, allowing the pixel to function even if one segment experiences a short circuit. This segmentation transforms the single-point-failure structure into a redundant multi-point structure, resolving the contradiction between reliability and complexity.
2Reliability
If multiple driving transistors and electrodes are added per pixel, then short circuit resistance improves, but manufacturing complexity increases
Solution Approach 1:
Multiple anodes within a pixel are connected to a common cathode, merging the electrode structure into a unified configuration that provides redundancy without requiring completely separate electrode systems. This merging approach improves short circuit resistance while maintaining manufacturing feasibility through standardized processes.
3Reliability
If a single anode is used, then the pixel circuit is simple, but short circuits cause complete pixel failure
Solution Approach 1:
The anode is segmented into multiple independent conductive regions (first anode and second anode) that can independently supply current to the organic emission layer. This segmentation ensures that if one region shorts to the cathode, the other region maintains pixel functionality, resolving the contradiction between reliability and structural simplicity.
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 ensures that even if a short circuit happens, the organic light emitting diode can still emit light through the other electrode, reducing the visibility of pixel defects and maintaining display functionality.
Implementation Method 1
An organic light emitting diode is an emissive device which emits fluorescent light by recombining electrons supplied from a cathode and holes supplied from an anode
Data Source
AI summary
An organic electroluminescent (EL) display device having a plurality of pixel circuits formed at crossing points of a plurality of scan lines and a plurality of data lines is provided. Each pixel circuit includes at least two driving transistors connected to a first power voltage line, the at least two driving transistors receiving a data signal through at least one of the data lines and outputting a driving current corresponding to the data signal; and an organic light emitting diode having at least two first electrodes respectively connected to the at least two driving transistors and emitting a light corresponding to the driving current. The organic light emitting diode has the at least two first electrodes and a common second electrode per pixel in order to prevent the whole pixel from not operating due to a short circuit occurring between one of the first electrodes and the second electrode.