AMOLED Cathode Voltage Drop via Non-Linear Via Distribution
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Solution Overview
Problem
Conventional large size active matrix organic light emitting diode (AMOLED) display panels face issues with inconsistent voltage drops due to high area resistance of the cathode, leading to poor brightness uniformity and display discrepancies.
Innovation Solution
A display panel design featuring an array substrate with a specific distribution of auxiliary cathodes and via holes, where the via hole distribution density follows a non-linear gradient, with higher densities near the center and decreasing towards the edges, to mitigate voltage drop discrepancies and enhance brightness uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the cathode thickness is reduced to guarantee light transmittance in top emission solution, then the light transmittance is improved, but the area resistance of the cathode becomes greatly high
Solution Approach 1:
The invention divides the cathode into multiple segments: a thin emitting cathode layer for light transmittance and multiple auxiliary cathode electrodes distributed across the substrate for electrical conduction. This segmentation allows each part to fulfill its specific function without compromising the other.
Solution Approach 2:
The auxiliary cathode electrodes act as intermediaries to compensate for the high area resistance of the thin emitting cathode. These auxiliary electrodes are connected to the emitting cathode through via holes, providing additional conduction pathways and reducing overall resistance.
2Reliability
If auxiliary cathode holes are distributed evenly in the entire surface, then the voltage drop is mitigated, but display discrepancy among different places is not resolved
Solution Approach 1:
The invention implements non-uniform distribution of auxiliary cathode holes with different densities in different regions. The hole density is higher in regions with greater voltage drops (typically edge regions) and lower in regions with smaller voltage drops (typically center regions), creating local optimization of electrical compensation.
Solution Approach 2:
The invention changes the parameter of auxiliary cathode hole density from a constant value to a spatially varying value. By adjusting the density parameter according to position, the system achieves better voltage compensation while maintaining display uniformity across different regions.
3Reliability
If the hole density varies linearly from center to edge, then the voltage drop discrepancy is eased, but sudden brightness variation appears in transition regions
Solution Approach 1:
The invention employs a dynamic, position-dependent hole density distribution that adapts to the local electrical characteristics of different regions. The density varies continuously and non-linearly across the substrate, optimizing compensation without creating abrupt transitions that would cause visible brightness variations.
Data Source
AI summary
The present invention provides a display panel and a display device, the display panel has an array substrate, and the array substrate has a substrate, a first inorganic film layer, at least one auxiliary cathode, a second inorganic film layer, and at least one via hole. The via hole is arranged in at least two voltage drop regions that are arranged sequentially. The via hole in each of the voltage drop regions is distributed evenly. A first voltage drop region is disposed opposite to a center or a side edge of the substrate.