Thin Film Transistor Array Substrate for High-Resolution X-Ray Detectors
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Solution Overview
Problem
Current high-resolution digital X-ray detectors face challenges in improving photo-sensitivity, reducing interference between PIN diodes, enhancing PIN diode stability, minimizing parasitic capacitance, and increasing the light-receiving area, which are crucial for achieving better performance in medical imaging applications.
Innovation Solution
A thin-film transistor array substrate design is proposed, featuring a PIN diode configuration with a third electrode inside the PIN diode, a planarization layer to reduce curvature and parasitic capacitance, and a bias line configuration that overlaps with data or gate lines but does not extend beyond them, maximizing the PIN diode area and fill factor while minimizing interference and capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the PIN diode area is increased to improve photo-sensitivity and fill factor, then the light-receiving area is maximized, but interference between adjacent PIN diodes increases
Solution Approach 1:
The second electrode of the thin-film transistor is disposed inside the PIN diode structure, nesting the transistor electrode within the diode's active region. This allows the PIN diode to extend closer to adjacent diodes without increasing external interference, as the internal electrode placement optimizes space utilization while maintaining electrical isolation.
Solution Approach 2:
The planarization layer is applied specifically in regions where electrode overlap occurs to locally reduce parasitic capacitance, while the PIN diode area is maximized in light-receiving regions. This localized optimization allows different parts of the device to have different structural characteristics suited to their specific functions.
2Reliability
If the planarization layer is added to reduce curvature and parasitic capacitance, then the stability and capacitance are improved, but the device complexity increases
Solution Approach 1:
The planarization layer serves multiple functions simultaneously: it flattens the substrate curvature to improve manufacturing uniformity, reduces parasitic capacitance between overlapping electrodes, and provides a stable base for subsequent electrode deposition. This multi-functionality justifies the added structural element by delivering multiple benefits from a single component.
3Area of moving object
If the second electrode is disposed inside the PIN diode, then the fill factor is improved, but parasitic capacitance increases
Solution Approach 1:
The planarization layer is strategically applied in the regions where the second electrode overlaps with the PIN diode structure. This localized treatment reduces parasitic capacitance precisely where the internal electrode placement creates overlap, while allowing the electrode to maintain its position for optimal fill factor in other regions.
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 enhances photo-sensitivity, stability, and reduces parasitic capacitance, leading to improved performance and resolution in digital X-ray detectors by maximizing the PIN diode area and fill factor, thereby addressing the limitations of existing technologies.
Implementation Method 1
a PIN diode on the first planarization layer, the PIN diode including a third electrode connected to the thin-film transistor, a PIN layer and a fourth electrode on the PIN layer
Data Source
AI summary
Disclosed are a thin-film transistor array substrate for a high-resolution digital X-ray detector and a high-resolution digital X-ray detector including the same, in which a photo-sensitivity is improved by increasing a fill factor, a stability of the PIN diode is improved, and generation of parasitic capacitance is reduced or minimized. In one embodiment, the PIN diode maximally extends so that electrodes and contact holes of the thin-film transistor is disposed inside the PIN diode. A planarization layer of organic material is present between the electrodes or wirings. Further, a light receiving region of the PIN diode is increased or maximized by positioning the bias line to overlap the data line or the gate line so as not to overlap with the PIN diode.