Compensation TFT Row for Parasitic Capacitance in X-ray Detection
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Solution Overview
Problem
Indirect X-ray imaging devices using thin film transistors face challenges due to parasitic capacitances between gate and source/drain electrodes, which affect signal output uniformity and accuracy, especially due to position shifts in the source/drain layer patterns during fabrication.
Innovation Solution
A detection substrate design incorporating a compensation thin film transistor row and dummy thin film transistor column, where the compensation thin film transistors have opposite source-drain directions and are connected to the same signal read lines as sensing thin film transistors, allowing for parasitic capacitance compensation and independent signal output from position shifts, along with a method for driving the substrate to combine and adjust electrical signals from sensing and compensation transistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If thin film transistor array is used to control electrical signal output, then signal output can be controlled for each pixel, but parasitic capacitance between gate and source/drain electrodes affects signal uniformity and accuracy
Solution Approach 1:
A compensation thin film transistor row is introduced as an intermediary component between the sensing thin film transistors and the signal read lines. This compensation row acts as a mediator to counterbalance the parasitic capacitance effects, allowing the original sensing transistors to maintain their signal control function while the compensation transistors adjust for uniformity and accuracy deviations
Solution Approach 2:
The invention changes the electrical parameters of the transistor array by adding compensation transistors with specifically designed gate electrode connections. By adjusting the gate electrode configurations and utilizing the opposite source-drain directions, the overall parasitic capacitance parameters are optimized to achieve uniform signal output across all pixels
2Measurement precision
If parasitic capacitance compensation is implemented using compensation thin film transistors, then signal uniformity and accuracy are improved, but device structure complexity increases
Solution Approach 1:
The transistor array is segmented into distinct functional regions: a sensing region containing the sensing thin film transistors for signal detection, and an auxiliary region containing the compensation thin film transistors for uniformity correction. This segmentation allows each region to perform its specific function independently while maintaining overall system simplicity through clear functional separation
Solution Approach 2:
The compensation thin film transistor row is positioned in the auxiliary region adjacent to the sensing region, utilizing the spatial dimension to separate compensation functions from sensing functions. This dimensional arrangement allows the compensation transistors to be electrically connected to the same signal read lines without interfering with the sensing transistor operations, thereby managing complexity through spatial organization
Data Source
AI summary
A detection substrate, a ray imaging device, and a method for driving a detection substrate are provided. The detection substrate includes a base substrate; a plurality of sensing TFTs; a plurality of signal read lines; a compensation TFT row including a plurality of compensation TFTs, wherein a first electrode of each of the compensation TFTs is electrically connected to the same signal read line as first electrodes of the sensing TFTs in corresponding sensing TFT column. As for the sensing TFTs and the compensation TFT electrically connected to the same signal read line, the first electrodes of both the sensing TFTs and the compensation TFT are source electrodes or drain electrodes, source-drain directions of the sensing TFTs are consistent with one another, and a source-drain direction of the compensation TFT is opposite to each of the source-drain directions of the sensing TFTs.