Organic Light Emitting Display Device Cathode Resistance Reduction
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Solution Overview
Problem
Top-emission type organic light emitting display devices face issues with high cathode resistance due to thin cathodes, leading to increased driving voltage and uneven luminance, which is exacerbated by conventional thick and wide dummy ground lines that increase the bezel area, making it difficult to design compact display devices.
Innovation Solution
The organic light emitting display device incorporates a substrate with a display area, scan driver areas, dummy areas, and wiring areas, where at least one line in the wiring area is electrically connected to the cathode through an anode in the scan driver area, reducing cathode resistance and bezel area by modifying the dummy ground line structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional thick and wide dummy ground line is formed in the bezel area, then the cathode resistance is reduced and driving voltage is prevented from increasing, but the bezel area increases making it difficult to design compact display devices
Solution Approach 1:
The dummy ground line is divided into multiple segments arranged in a grid pattern rather than using a single continuous thick line. This segmentation allows the ground connection function to be distributed across multiple smaller conductive paths, reducing the overall bezel area while maintaining effective cathode grounding.
Solution Approach 2:
The dummy ground line is transformed from a one-dimensional linear structure into a two-dimensional grid pattern. This dimensional change allows the ground connection to cover a larger effective area with thinner lines, reducing the bezel area occupation while maintaining low cathode resistance through multiple parallel conduction paths.
2Ease of manufacture
If a thin cathode is used in top-emission type organic light emitting display devices, then the device structure is simplified and manufacturing is easier, but the cathode resistance increases leading to increased driving voltage and uneven luminance
Solution Approach 1:
The dummy ground line acts as an intermediary element that compensates for the high resistance of the thin cathode. By providing additional ground connection paths through the dummy ground line structure, the overall resistance is reduced without requiring the cathode itself to be thicker, thus maintaining manufacturing simplicity while improving electrical performance.
Solution Approach 2:
The resistance parameter of the cathode system is modified by adding parallel conduction paths through the dummy ground line configuration. This changes the overall resistance characteristic from being dominated by the thin cathode to being distributed across multiple paths, effectively reducing the total resistance without altering the cathode thickness.
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 reduces cathode resistance, prevents voltage increase, and improves display quality by minimizing bezel area, enabling the design of more compact display devices while maintaining image directionality through the transparent cathode.
Implementation Method 1
electrons from the cathode and holes from the anode are injected into the light emitting layer and combined to generate excitons and light is emitted when the excitons are dropped from an excited state to a ground state
Data Source
AI summary
Provided is an organic light emitting display device which comprises a display area defined on a substrate, the display area comprise a display part having a sub pixels, scan driver areas respectively located at the left and right sides of the display area and including scan drivers which provide scan signals to the sub pixels, dummy areas respectively defined between the display area and the scan driver areas, and a wiring areas defined outside each of the scan driver areas and including a gate line and a source/drain line which are insulated from each other by insulating layers formed on the substrate and respectively located at different layers, wherein at least one of lines disposed in the wiring areas is electrically connected to a cathode located in the display area through an anode disposed in the scan driver areas.