Radiation Imaging Pixel Readout With Shared Column Lines
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Solution Overview
Problem
Existing radiation imaging apparatuses face challenges in accurately detecting radiation irradiation information due to high circuit complexity and cost, particularly in the readout circuit, which integrates analog amplifiers and A/D conversion circuits at a high density.
Innovation Solution
The apparatus employs a configuration where adjacent pixels with different sensitivities share a common column signal line and are driven at different timings, allowing the detection circuit to accurately detect irradiation information by subtracting signals from these pixels, thereby reducing the circuit scale and suppressing crosstalk and offset components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If adjacent pixels with different sensitivities share a common column signal line and are driven at different timings, then the detection accuracy of irradiation information is improved while the circuit scale of the readout circuit is reduced
Solution Approach 1:
Two adjacent pixels (first pixel and second pixel) share a common column signal line, merging their output paths into a single signal line. This reduces the number of column signal lines required in the readout circuit, thereby reducing circuit scale while maintaining the ability to distinguish individual pixel signals through differential timing control
Solution Approach 2:
The driving circuit drives the first pixel and second pixel at different timings in a periodic manner, allowing the detection circuit to distinguish between signals from different pixels even though they share the same column signal line. This temporal separation enables accurate radiation detection while using fewer physical circuit components
2Device complexity
If multiple pixels share common signal lines, then the circuit scale is reduced, but crosstalk and offset components increase
Solution Approach 1:
By driving adjacent pixels at different timings and detecting their signals sequentially, the system minimizes crosstalk between pixels sharing the same column signal line. The temporal separation ensures that signals from different pixels do not overlap, reducing interference while maintaining circuit compactness
Solution Approach 2:
The detection circuit extracts irradiation information specifically from the difference between signals of the first pixel and second pixel. By focusing on the differential signal rather than absolute values, the system removes offset components and isolates the actual radiation detection data from background noise and circuit interference
3Productivity
If analog amplifiers and A/D conversion circuits are integrated at high density, then the readout capability is improved, but the cost and circuit complexity increase
Solution Approach 1:
Multiple pixels share common column signal lines and readout circuitry, reducing the total number of amplifiers and A/D conversion circuits required. This merging approach maintains full readout capability across all pixels while significantly reducing the density and scale of the readout circuit, thereby lowering cost and complexity
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 approach enhances the accuracy of Automatic Exposure Control (AEC) by minimizing the influence of crosstalk and offset components, leading to improved detection of radiation irradiation start/end and dose, while reducing the readout circuit's complexity and cost.
Implementation Method 1
a sensor board including a plurality of pixels configured to change incident radiation into an electrical signal
Data Source
AI summary
A radiation imaging apparatus comprising pixels, a driver controlling the pixels via driving lines, a readout circuit reading out, via column signal lines, signals from the pixels and a detector detecting irradiation information of radiation separately from a radiation image, is provided. Each of the column signal lines is connected to pixels arranged on two pixel columns. The pixels include a first pixel and a second pixel, whose sensitivities are different from each other. The first and second pixels are connected to a common column signal line and are connected to driving lines different from each other. When detecting the irradiation information, the driver drives the first and second pixels at timings different from each other, and the detection circuit detects the irradiation information based on signals output from the first and second pixels.