X-ray Detector Array Substrate Test Patterns for Measurement Accuracy
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Solution Overview
Problem
Conventional X-ray detectors face challenges in accurately measuring the characteristics of both thin film transistors and optical detectors due to their structural integration, leading to mixed evaluation results and decreased accuracy.
Innovation Solution
The introduction of an array substrate with separate test patterns for transistors and optical detectors, allowing for distinct evaluation of each component's characteristics within the X-ray detector, thereby preventing mixed evaluation and enhancing measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a test pattern is added to the edge portion of the sheet material of the base substrate outside the array substrate, then the array substrate structure is simple and easy to manufacture, but the test pattern is distant from the active area and measurement accuracy is lowered
Solution Approach 1:
The patent divides the test pattern into separate regions: a first test pattern for transistor characteristics and a second test pattern for optical detector characteristics. This segmentation allows each component to be tested independently with appropriate test structures positioned optimally for measuring their specific characteristics, thereby improving measurement accuracy while maintaining manufacturing simplicity.
Solution Approach 2:
The patent positions test patterns in multiple locations across the array substrate rather than confining them to a single edge portion. By distributing test patterns in different dimensions and locations, the measurement points are brought closer to the active areas they need to test, improving accuracy without complicating the manufacturing process.
2Device complexity
If thin film transistor and optical diode are present in one pixel, then the device structure is compact and integrated, but it is difficult to evaluate unique characteristics of each component
Solution Approach 1:
The patent creates separate test patterns for transistor characteristics and optical detector characteristics, allowing independent evaluation of each component type. The first test pattern evaluates transistor characteristics while the second test pattern evaluates optical detector characteristics, enabling precise measurement of each component's unique properties despite their integrated presence in the same pixel structure.
Solution Approach 2:
The patent applies different test structures and measurement approaches to different components within the pixel. By tailoring the test pattern design to the specific characteristics of transistors and optical detectors separately, the evaluation method adapts to the local quality requirements of each component, achieving accurate measurement of unique characteristics.
3Reliability
If cesium component is applied over the active area, then the scintillator can detect X-ray effectively, but the cesium component corrodes metallic lines of the array substrate
Solution Approach 1:
The patent extracts the test patterns from the area under the scintillator to locations where they are not exposed to cesium corrosion. By positioning test patterns in regions free from cesium application, the harmful corrosive effect is eliminated while the scintillator maintains its X-ray detection effectiveness over the active area.
Solution Approach 2:
The patent introduces a protective organic layer as an intermediary between the cesium component and the metallic lines of the array substrate. This intermediary layer prevents direct contact between the corrosive cesium and the metal, eliminating corrosion while allowing the scintillator to function effectively.
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 enables precise characterization of both transistors and optical detectors, reducing defective products, improving yield, and lowering costs associated with preventing defects.
Implementation Method 1
a photodiode in each of the cell regions to perform photoelectric conversion
Implementation Method 2
when an X-ray is converted into the visible ray by a scintillator
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
The present disclosure relates to an array substrate for an X-ray detector and an X-ray detector including the same. The array substrate is defined as an active area and a pad area, wherein the pad area comprises a plurality of test areas comprising a first test pattern and a second test pattern, the first test pattern comprises a first gate electrode on a substrate, a first active layer on the first gate electrode, a first source/drain electrode on the first active layer, and a first data line on the first source/drain electrode, and the second test pattern comprises a first lower electrode on the substrate, a first photoconductive layer on the first lower electrode, and a first upper electrode on the first photoconductive layer, thereby measuring the characteristic of each of a transistor and an optical detector with high accuracy.