OLED Display Device Subpixel Wiring Current Variation
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Solution Overview
Problem
In OLED display configurations where the drive transistor has N channels, the source follower configuration leads to variations in current values due to connections between the anode electrodes and OLED sources.
Innovation Solution
A display device design featuring a cathode electrode on a subpixel-by-subpixel basis, a common anode electrode for multiple subpixels, a light emitting layer between the cathode and anode electrodes, and wiring lines structured to reduce current variations, with a first wiring line in the same layer as the cathode and a second wiring line overlapping the first wiring line and positioned below the anode electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a source follower configuration is adopted with N channels connected to anode electrodes of OLED, then the drive transistor can control multiple subpixels, but the current value of the OLED tends to vary
Solution Approach 1:
The anode electrode is divided into multiple independent anode electrode patterns corresponding to different subpixels. Each anode electrode pattern is independently connected to the source follower configuration, allowing separate control and compensation for each subpixel's current characteristics. This segmentation enables precise control of current distribution across multiple OLEDs while maintaining stability.
Solution Approach 2:
The patent implements subpixel-by-subpixel control architecture where each subpixel has its own cathode electrode, anode electrode pattern, and associated drive circuitry. This local quality approach allows each subpixel to be independently optimized and controlled, compensating for variations in current characteristics while maintaining overall display performance.
2Device complexity
If anode electrode is provided commonly for multiple subpixels, then the structure is simplified, but current variation between subpixels increases
Solution Approach 1:
The common anode electrode is segmented into multiple independent anode electrode patterns, each corresponding to a specific subpixel. This segmentation maintains the simplified common anode structure while enabling independent current control for each subpixel, thereby reducing current variation without significantly increasing overall structural complexity.
Solution Approach 2:
The patent introduces intermediate conductive layers and wiring structures between the common anode electrode and individual subpixels. These intermediary elements enable independent electrical connection and control for each subpixel while maintaining the common anode architecture, thus reducing current variation without requiring completely separate anode electrodes for each subpixel.
Data Source
AI summary
A display device includes a cathode electrode provided on a subpixel-by-subpixel basis, an anode electrode provided commonly for a plurality of subpixels in an upper layer with respect to the cathode electrode, a light emitting layer provided between the cathode electrode and the anode electrode, a first wiring line provided in the same layer as the cathode electrode, and a second wiring line provided in an upper layer with respect to the first wiring line and superimposed on the first wiring line.