Dual-Gate TFT Active Matrix Panel Leakage Current Control
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Solution Overview
Problem
Conventional digital radiography technologies experience image distortion due to leakage current issues caused by high-intensity light illumination, which affects the voltage difference between electrodes in thin-film transistors, leading to unwanted electricity leakage.
Innovation Solution
An active matrix image sensing panel design with a specific electrode configuration, including a photo sensing element with a higher voltage first terminal electrode and a thin-film transistor (TFT) element with a dual-gate structure, where the second gate electrode is connected to the second terminal electrode, preventing the TFT from being enabled even when the voltage difference increases, thus preventing leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If high-intensity light illumination is applied to the photo sensor, then the image sensing capability is improved, but the voltage difference between gate and source electrodes continuously ascends causing TFT to turn on and leak electricity
Solution Approach 1:
The patent changes the electrical parameters of the TFT by introducing a second gate electrode that can independently control the threshold voltage. By adjusting the voltage on the second gate, the threshold voltage is dynamically modified to prevent the TFT from turning on during high-intensity illumination, thus resolving the contradiction between image sensing capability and leakage current prevention
Solution Approach 2:
The second gate electrode acts as an intermediary control element between the photo sensor and the data line. It mediates the effect of high-intensity light by providing an additional control point that can counteract the voltage changes caused by illumination, preventing unwanted TFT activation and leakage current
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 solution effectively increases the threshold voltage of the TFT, preventing leakage current and maintaining undistorted image sensing, even under high-intensity light conditions.
Implementation Method 1
a scintillator will convert X-ray into visible light that is then sensed by photo sensors and thus converted into electric signals
Data Source
AI summary
An active matrix image sensing panel comprises a substrate and an image sensing pixel. The image sensing pixel is disposed on the substrate and comprises a scan line, a data line crossing the scan line, a photo sensing element and a TFT element. The photo sensing element includes a first terminal electrode and a second terminal electrode, and the voltage of the first terminal electrode is higher than that of the second terminal electrode. The TFT element includes a first electrode, a second electrode, a first gate electrode and a second gate electrode. The first electrode is electrically connected to the data line, the second electrode is electrically connected to the first terminal electrode, the first gate electrode is electrically connected to the scan line, and the second gate electrode is electrically connected to the first or second terminal electrode. An active matrix image sensing apparatus is also disclosed.