Radiation Imaging Pixel Layout for Accurate Line Noise Correction
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Solution Overview
Problem
Existing radiation imaging apparatuses face challenges in accurately correcting line noise, particularly at high frame rates, due to fluctuations in supply voltage, which affect image quality and require improved noise correction methods.
Innovation Solution
The apparatus includes a combination of effective pixels and line noise correction pixels with equivalent parasitic capacitance ratios, utilizing thin-film transistors and capacitive elements to correct line noise, ensuring accurate signal correction by matching the capacitance ratios between signal lines and employing additional light-shielded pixels to account for temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If high frame rate operations are performed using TFTs formed of IGZO or p-Si, then imaging speed is improved, but line noise increases due to fluctuations in supply voltage
Solution Approach 1:
A second pixel is introduced as an intermediary element that does not contribute to image formation but specifically captures line noise components. This mediator pixel enables the separation and correction of noise from the actual image signal, allowing high frame rate operation while maintaining image quality through noise subtraction.
Solution Approach 2:
The system implements a feedback mechanism where the output of the second pixel (capturing noise) is fed back to correct the output of the first pixel (capturing image). By continuously monitoring and subtracting the noise component captured in the second pixel from the first pixel's output, the system dynamically compensates for voltage fluctuations and line noise in real-time.
2Object-generated harmful factors
If a capacitive element is provided outside pixels for line noise correction, then line noise correction is enabled, but measurement precision deteriorates due to different capacitance ratios between effective pixels and capacitive element
Solution Approach 1:
The second pixel is designed with homogeneous structural characteristics identical to the first pixel, including the same TFT configuration and signal line connections. This homogeneity ensures that both pixels experience the same capacitance ratios and electrical characteristics, enabling accurate noise measurement and correction without the precision loss associated with external capacitive elements.
Solution Approach 2:
The second pixel serves as a copy of the first pixel's electrical and structural configuration, but without the photoelectric conversion function. By copying the same capacitance ratios and electrical characteristics, the second pixel accurately replicates the noise behavior of the first pixel, enabling precise noise correction through direct comparison.
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 configuration effectively corrects line noise with high accuracy and reduces output changes caused by temperature variations, enhancing the overall image quality and stability of the radiation imaging process.
Implementation Method 1
a first pixel that includes a first photoelectric conversion element and a first thin-film transistor and is used in image acquisition
Data Source
AI summary
An apparatus includes: a first pixel for acquiring an image, the first pixel including a first conversion element and a first thin-film transistor and connected to a first signal line; and a second pixel for correcting an output of the first pixel, the second pixel including an element and a second thin-film transistor and connected to a second signal line, in which a ratio between a plurality of capacitances related to the first signal line and a ratio between a plurality of capacitances related to the second signal line are approximately equivalent.