X-ray Detector Array Substrate with Light Blocking Layer
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Solution Overview
Problem
Conventional x-ray detectors with array substrates suffer from manufacturing cost inefficiencies and image quality issues due to defects in the uniformity of lines and photodiodes, leading to low resolution, brightness, and contrast ratios, especially when multiple substrates are combined in a tile-like structure.
Innovation Solution
The implementation of a single array substrate with a light blocking layer made of carbon-containing organic material, which covers dummy pixels and improves image quality by real-time gain and offset correction, reducing the number of read-out circuits and analog-to-digital converters, and enhancing the uniformity of gate and data lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a tile-like structure with four array substrates is used to increase sensor area, then the sensor size is increased, but the number of defects increases and manufacturing complexity increases
Solution Approach 1:
The array substrate is divided into multiple blocks (first block, second block, third block, fourth block) with each block containing multiple cells. This segmentation allows for modular manufacturing and assembly, reducing the overall defect rate by isolating potential failures to specific blocks rather than affecting the entire sensor array.
2Adaptability or versatility
If external integrated circuits are bonded to every array substrate, then functionality is enhanced, but manufacturing complexity and defect rate increase
Solution Approach 1:
The gate driver and read-out circuit are integrated directly into the array substrate as on-substrate circuits rather than being implemented as separate external integrated circuits. This merging of functions reduces manufacturing complexity by eliminating bonding processes and reduces defect rates while maintaining full functional capability for driving TFT arrays and reading out signals.
3Ease of manufacture
If gate and data lines are separated in tile-like structures, then manufacturing is simplified, but offset correction precision deteriorates
Solution Approach 1:
Dummy pixels are strategically placed at specific locations (first dummy pixel, second dummy pixel, third dummy pixel, fourth dummy pixel) around the active pixel areas. These dummy pixels have the same structure as active pixels but are not used for imaging, allowing for local offset correction and uniformity adjustment in specific regions without affecting the entire array, thereby improving offset correction precision while maintaining manufacturing simplicity.
4Ease of manufacture
If dummy pixels are exposed to light, then manufacturing is simpler, but image quality deteriorates due to unwanted light reception
Solution Approach 1:
A light blocking layer is formed over the dummy pixels to extract and remove the harmful effect of light reception from these non-functional pixel regions. The light blocking layer selectively blocks light from reaching the dummy pixels while allowing light to reach the active pixel areas, thereby preventing unwanted light reception that would degrade image quality without complicating the manufacturing process.
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 solution reduces manufacturing costs and improves image quality by minimizing defects and correcting offset voltage differences, resulting in higher resolution and contrast ratios in x-ray images.
Implementation Method 1
a light blocking layer to cover dummy pixels of the cells, the light blocking layer being arranged in a peripheral area of the x-ray detector so as to be positioned to block light advancing toward the dummy pixels
Implementation Method 2
a photodiode connected to the thin film transistor to receive the light as having been converted from an x-ray
Data Source
AI summary
An x-ray detector including an array substrate including blocks extending along the array substrate in a first direction. Each of the blocks includes cells that are each associated with a data line extending in parallel with the first direction and a gate line extending perpendicularly to the first direction such that the data line crosses the gate line, a thin film transistor respectively connected to the gate and data lines, and a photodiode connected to the thin film transistor to receive light. The cells store charges corresponding to an amount of the light. Gate drivers are connected to ends of the gate lines to select rows of the cells associated with each of the gate lines. Read-out circuits are connected to ends of the data lines to read out charges stored in the cells, of each of the selected rows, that are respectively associated with each of the data lines.