Photodiode-Covered TFT Sensor for Enhanced Light Absorption
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Solution Overview
Problem
Existing sensors have a small light receiving area, low absorption and utilization ratio of light, leading to high energy dissipation and limited imaging quality in medical imaging applications.
Innovation Solution
A sensor design featuring a substrate with crossing gate and data lines, each sensing unit comprising a thin film transistor device and a photodiode sensor device, where the photodiode and transparent electrode cover the thin film transistor device, increasing the light receiving area and absorption ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the photodiode coverage is increased to improve light receiving area, then the light absorption and utilization ratio improves, but the device structure becomes more complex
Solution Approach 1:
The patent merges the photodiode structure with the TFT structure by having the photodiode cover the entire TFT device area. The photodiode is integrated directly over the gate, source, drain, and channel regions, creating a combined structure where the photodetection function encompasses the entire transistor area, thereby maximizing light receiving area without proportionally increasing structural complexity
Solution Approach 2:
The patent extends the photodiode coverage from a traditional limited area to a two-dimensional expansion that covers the entire TFT device footprint. By spreading the photodiode coverage across the full device area in the planar dimension, the light receiving area is maximized without requiring additional vertical layers or three-dimensional structures
2Manufacturing precision
If the photodiode coverage is increased to improve light absorption ratio, then the imaging quality improves, but the manufacturing process becomes more complex
Solution Approach 1:
The patent makes the photodiode structure serve multiple functions: it acts as both the light-receiving element and the reference electrode for the TFT device. This multi-functional design improves imaging quality through enhanced light absorption while avoiding additional manufacturing steps that would be required for separate reference electrode structures
Solution Approach 2:
The patent segments the photodiode coverage into distinct functional zones corresponding to different TFT regions (gate area, source-drain area, channel area). This segmentation allows the manufacturing process to address different coverage areas systematically through standardized patterning steps, reducing overall process complexity
3Device complexity
If the traditional TFT structure is used with limited photodiode coverage, then the device structure remains simple, but the light receiving area is small and energy dissipation is high
Solution Approach 1:
The patent changes the key parameter of photodiode coverage area from a limited traditional value to an extended value that covers the entire TFT device. This parameter change directly increases light absorption efficiency and reduces energy dissipation while maintaining compatibility with existing TFT fabrication parameters and processes
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
Enhances imaging quality by increasing the light receiving area and absorption ratio, while reducing energy dissipation compared to traditional sensors.
Implementation Method 1
each sensing unit comprising a thin film transistor device and a photodiode sensor device
Data Source
AI summary
Embodiments of the present invention disclose a sensor and a method for manufacturing the same, the sensor comprising a plurality of sensing units arranged in array, each of which comprises a thin film transistor device and a photodiode sensor device and the photodiode sensor device comprising: a receiving electrode connected with a drain of the thin film transistor device, a photodiode located on the receiving electrode and covering the thin film transistor device, a transparent electrode on the photodiode and a biasing line connected with the transparent electrode.