Pixel Array Substrate with Horizontal Photosensitive Layer
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Solution Overview
Problem
Conventional X-ray detectors with amorphous silicon photodiode arrays require complex manufacturing processes, leading to low yield rates and high costs due to their vertical multi-layer stacking structure, which complicates large-scale production and limits aperture rates.
Innovation Solution
A pixel array substrate with a horizontal photosensitive resistance layer replaces the conventional vertical multi-layer structure, using indium gallium zinc oxide (IGZO) for improved electron mobility and stability, and simplifies the manufacturing process by reducing the number of lithography steps, allowing for a 100% aperture rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a vertical multi-layer stacking structure with amorphous silicon photodiode arrays is used, then the detector can achieve basic light detection function, but the manufacturing process becomes too complicated with more than 11 processes
Solution Approach 1:
The patent combines the photodiode array and thin-film transistor into a single integrated pixel structure manufactured in one process sequence. The pixel structure includes a substrate, light-receiving layer, charge-generating layer, charge-transporting layer, and electrode layer all formed together, eliminating the need for separate manufacturing processes for photodiodes and transistors.
Solution Approach 2:
The pixel structure serves multiple functions simultaneously: the light-receiving layer detects light, the charge-generating layer creates electron-hole pairs, the charge-transporting layer moves charges, and the electrode layer collects signals. This multi-functional integration replaces the conventional separate photodiode and transistor structures.
2Reliability
If more film layers are added to the vertical multi-layer stacking structure, then the energy barrier is increased to avoid leakage current, but the manufacturing difficulty increases and yield rate decreases
Solution Approach 1:
The patent changes the material parameters by using organic semiconductor materials with inherently high energy barriers and low leakage currents. The charge-transporting layer uses materials like triphenylamine derivatives that provide high hole mobility and effective leakage current suppression without requiring additional film layers.
Solution Approach 2:
The patent extracts and eliminates unnecessary intermediate film layers from the conventional structure. By using the integrated pixel structure with carefully selected organic materials, the design removes redundant layers while maintaining or improving leakage current control through material properties rather than structural complexity.
3Reliability
If the photodiode array and thin-film transistor are manufactured separately, then each component can be optimized, but the patterned area of the pixel is limitary and aperture rate is at most about 70%
Solution Approach 1:
The patent merges the photodiode and transistor functions into a single integrated pixel structure where the light-receiving layer, charge-generating layer, and charge-transporting layer are formed together on the same substrate. This integration allows the entire pixel area to be utilized for light detection, achieving 100% aperture rate.
Solution Approach 2:
The patent transitions from a vertical stacking approach to a layered horizontal integration approach. The multiple functional layers are stacked vertically but integrated within a planar pixel structure, allowing full utilization of the pixel area while maintaining functional separation through vertical layering.
4Reliability
If conventional amorphous silicon photodiode arrays are used, then the detector can operate, but the manufacturing requires more than 11 processes which are too complicated for large scale production
Solution Approach 1:
The patent changes the material system from conventional amorphous silicon to organic semiconductor materials that can be processed using solution-based techniques. The organic charge-transporting layer and charge-generating layer can be deposited from solutions, reducing the number of high-vacuum deposition and lithography steps required.
Solution Approach 2:
The patent replaces complex mechanical vacuum deposition and lithography processes with solution-based deposition methods. The organic layers can be deposited by coating, printing, or spinning from liquid solutions, eliminating the need for multiple vacuum chamber transfers and photoresist processing steps.
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 reduces manufacturing difficulties and costs while increasing yield rates and aperture rates, achieving superior performance with fewer processes and higher stability compared to conventional methods.
Implementation Method 1
The photosensitive resistance layer combines with the contact electrode, the second data line and the third data line to compose a light detecting component
Implementation Method 2
When the light source of the X-ray detector emits an X-ray of a specific wavelength, the X-ray, first of all, is converted into a visible light by a scintillator
Implementation Method 3
after receiving the visible light, the photodiode arrays generate an electron-hole pair which is collected by the electrode to generate an electrical signal
Data Source
AI summary
A pixel array substrate including a substrate and a plurality of pixel structures is provided. Each pixel structure includes a patterned metal layer, an insulating layer, a patterned semiconductor layer and a data line layer. The patterned metal layer includes a gate line and a common electrode line. The patterned semiconductor layer includes a channel layer and a photosensitive resistance layer. The channel layer is disposed above and overlaps a part of the gate line. The data line layer includes a patterned first data line, a second data line and a third data line. The first and the second data lines are coupled to the channel layer and combine with the channel layer and the gate line to compose an active component. The second and the third data lines are coupled to the photosensitive resistance layer and combine with the photosensitive resistance layer to compose a light detecting component.