Thin Film Transistor Light-Shielding Layer Gate Voltage Control
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Solution Overview
Problem
Existing digital X-ray detectors suffer from leakage current and noise due to the application of bias voltage to the light-shielding layer, which forms a back channel in the thin film transistor, causing unwanted current flow and signal noise.
Innovation Solution
Applying a gate voltage to the light-shielding layer instead of a bias voltage to shield the channel region of the thin film transistor, ensuring the light-shielding layer is electrically connected to the gate line, thereby preventing back channel leakage current and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If bias voltage is applied to the light-shielding layer, then the light-shielding layer can shield the channel region, but back channel leakage current and noise are generated
Solution Approach 1:
The patent changes the voltage parameter applied to the light-shielding layer from bias voltage to gate voltage. This parameter change eliminates the formation of back channel while maintaining the light shielding function, as gate voltage controls the main channel rather than creating back channel leakage.
Solution Approach 2:
The light-shielding layer is made electrically connected to the gate line, allowing it to serve dual functions: providing light shielding and receiving gate voltage control. This multi-functionality enables the layer to maintain shielding effectiveness while avoiding the harmful back channel effect through proper voltage application.
2Reliability
If the light-shielding layer is electrically connected to the gate line, then gate voltage is applied to stabilize transistor characteristics, but the structure becomes more complex
Solution Approach 1:
The patent merges the light-shielding layer with the gate line electrical connection, combining two previously separate functions into a single integrated structure. This reduces overall device complexity while achieving both light shielding and gate voltage application for stabilized transistor characteristics.
3Object-generated harmful factors
If gate voltage is applied during detection, then leakage current is reduced, but the control mechanism becomes more stringent
Solution Approach 1:
The light-shielding layer automatically receives gate voltage through its electrical connection to the gate line, eliminating the need for separate bias voltage application. The system self-regulates the voltage to prevent back channel formation while maintaining shielding effectiveness, reducing operational complexity.
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 approach reduces leakage current and noise in the output signal by stabilizing the thin film transistor characteristics and maintaining consistent gate voltage during detection, improving the reliability and accuracy of the digital X-ray detector.
Implementation Method 1
The photodiode (PD) is a device that converts incident light into an electrical detection signal through photoelectric effect
Implementation Method 2
each light-shielding layer electrically connected to the respective gate line... Applying a gate voltage to the light-shielding layer instead of a bias voltage to shield the channel region of the thin film transistor
Data Source
AI summary
A thin film transistor array substrate for a digital photo-detector is provided. The photo-detector includes a plurality of gate lines to supply a scan signal; a plurality of data lines to output data, the data lines arranged in a direction crossing the gate lines, wherein cell regions are defined by the gate lines and the data lines; a photodiode in each of the cell regions to perform photoelectric conversion; a thin film transistor at each intersection between the gate lines and the data lines to output a photoelectric conversion signal from the photodiode to the data lines in response to a scan signal supplied by the gate lines; and a light-shielding layer over each channel region of the respective thin film transistors. Each light-shielding layer is electrically connected to the respective gate line.