OLED Display Panel Via-Hole Layout for TFT Hysteresis Reduction
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Solution Overview
Problem
Thin film transistors made with low-temperature polysilicon technology in conventional OLED panels exhibit serious hysteresis, leading to fluctuations in output current and resulting in afterimages, particularly affecting green and red images under the same grayscale.
Innovation Solution
A display panel design that includes a substrate with specific configurations of driving thin film transistors, capacitors, and organic light-emitting diodes, where the opening areas of via holes are optimized to enhance hydrogen removal and electrical properties, specifically with larger opening areas for the green OLED device to improve afterimage issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If low-temperature polysilicon technology is used for thin film transistors, then manufacturing cost and ease of manufacture are improved, but hysteresis increases causing output current fluctuations and afterimages
Solution Approach 1:
The patent applies different via hole opening areas for different color sub-pixels (green sub-pixel has larger via hole opening area than red and blue sub-pixels) to compensate for the hysteresis effect. This local differentiation addresses the specific problem that green sub-pixels suffer more severe afterimage issues, by providing enhanced hydrogen removal at the location where it is most needed, thus resolving the contradiction between ease of manufacture and reliability.
2Device complexity
If uniform via hole opening areas are used for all sub-pixels, then device complexity is reduced, but afterimage quality deteriorates due to insufficient hydrogen removal from driving transistors
Solution Approach 1:
The patent implements non-uniform via hole opening areas where the green sub-pixel's via hole has a larger opening area compared to red and blue sub-pixels. This local quality differentiation targets the specific issue that green sub-pixels experience more severe afterimage problems, providing enhanced hydrogen removal capacity exactly where needed, thus improving afterimage quality without significantly increasing overall device complexity.
3Reliability
If larger via hole opening areas are used for green OLED devices, then hydrogen removal and electrical properties are improved reducing afterimages, but manufacturing precision requirements increase
Solution Approach 1:
The patent specifies that the via hole opening area for the green sub-pixel should be larger than that for red and blue sub-pixels (with specific ratio ranges provided). This targeted approach improves afterimage quality for green images by enhancing hydrogen removal at the critical location, while the provided dimensional ratios help manage manufacturing precision requirements by giving clear design guidelines.
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
The optimized configuration reduces hysteresis in the driving transistors, enhancing the electrical properties and improving afterimage quality, particularly for green and red images, by increasing hydrogen removal and ensuring the required driving currents for uniform light-emitting brightness.
Implementation Method 1
the opening area of the at least one first via hole is a first opening area, an opening area of the at least one second via hole is a second opening area, and the first opening area is larger than the second opening area
Data Source
AI summary
The present invention provides a display panel. A first power line is electrically connected to a first capacitor through at least one first via hole, and the first capacitor is electrically connected to a first driving thin film transistor (TFT). A second power line is electrically connected to a second capacitor through at least one second via hole, and the second capacitor is electrically connected to a second driving TFT. An opening area of the at least one first via hole is a first opening area, an opening area of the at least one second via hole is a second opening area, and the first opening area is larger than the second opening area.