Dual-Gate Thin-Film Transistor for High-Resolution Image Sensor Noise Reduction
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Solution Overview
Problem
Conventional flat panel detectors with passive pixel sensors suffer from reduced signal-to-noise ratio due to smaller pixel sizes, which limits their performance in high-resolution imaging applications.
Innovation Solution
The implementation of an image sensor with a plurality of pixels on an insulating substrate, each equipped with a photoelectric conversion element, a first thin-film transistor with a double-gate structure, a second thin-film transistor, and a third thin-film transistor, where the second gate has smaller capacitance than the first gate, and a constant current source is used to amplify signals effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pixel size is reduced to achieve higher resolution, then imaging resolution is improved, but signal-to-noise ratio deteriorates
Solution Approach 1:
The patent changes the electrical parameters of the transistor by introducing a dual-gate structure with different capacitance values. The first gate has larger capacitance to receive and amplify the photoelectric signal, while the second gate has smaller capacitance to reduce noise coupling and interference, thereby improving signal-to-noise ratio while maintaining small pixel size for high resolution
Solution Approach 2:
The patent applies different capacitance characteristics to different gates of the same transistor. The first gate is designed with larger capacitance to enhance signal amplification, while the second gate is designed with smaller capacitance to minimize noise, creating localized functional differentiation within the transistor structure to simultaneously achieve high resolution and high signal-to-noise ratio
2Measurement precision
If pixel size is reduced to achieve higher resolution, then imaging resolution is improved, but signal amount decreases
Solution Approach 1:
The patent changes the capacitance parameters of the transistor gates to optimize signal handling. The first gate's larger capacitance allows it to accumulate and amplify the reduced signal from smaller pixels, effectively compensating for the decreased signal amount while maintaining the small pixel size required for high resolution
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 configuration enhances the signal amplification rate and maintains a high signal-to-noise ratio even with smaller pixels, enabling high-resolution imaging without compromising performance.
Implementation Method 1
a photoelectric conversion element
Data Source
AI summary
An image sensor is disclosed. A first thin-film transistor includes a first gate and a second gate. The first gate is supplied with a signal generated by a photoelectric conversion element. The second gate is supplied with a potential different from a potential of a first signal line by a predetermined voltage through a second signal line. The second gate has a smaller capacitance than the first gate. A second thin-film transistor supplies a reset potential received from a reset power line to the photoelectric conversion element. Whether a third thin-film transistor is in a conductive state is controlled by a selection signal. The third thin-film transistor is disposed between the first signal line and the first thin-film transistor and the current from a constant current source flows into the first thin-film transistor via the third thin-film transistor in a conductive state.