Oxide Semiconductor Pixel Circuit Radiation Correction
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Solution Overview
Problem
Flat panel detectors used in medical imaging devices experience changes in electrical characteristics due to radiation, leading to decreased reliability of acquired data, particularly in pixel circuits with semiconductor or insulating materials.
Innovation Solution
An imaging device incorporating a pixel circuit with an oxide semiconductor transistor, a current detection circuit, A/D converter, memory circuits, and an arithmetic circuit, which includes look-up tables to correct output values and store programs for reading transistor characteristics, ensuring accurate data acquisition despite changes in transistor characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a flat panel detector with semiconductor or insulating materials is used in pixel circuits, then the detector can acquire image data, but the electrical characteristics of transistors change due to radiation, decreasing data reliability
Solution Approach 1:
The patent changes the material parameter of the transistor from conventional semiconductor or insulating materials to oxide semiconductor materials. This material parameter change makes the transistor characteristics less sensitive to radiation, thereby maintaining electrical characteristic stability and data reliability under radiation exposure.
Solution Approach 2:
The patent introduces a correction mechanism using look-up tables stored in memory circuits. Instead of relying solely on inherently stable materials, the system uses correctable data that can compensate for transistor characteristic changes, effectively making the system resilient to radiation-induced degradation.
2Measurement precision
If conventional transistors are used in pixel circuits, then the device structure is simpler, but output accuracy decreases due to radiation-induced characteristic changes
Solution Approach 1:
The patent introduces look-up tables as intermediary components that mediate between the pixel circuit output and the final image data. These look-up tables store correction values that compensate for radiation-induced errors, thereby improving measurement precision without requiring fundamental changes to the transistor structure.
Solution Approach 2:
The patent segments the correction function into separate look-up tables stored in memory circuits, distinct from the pixel circuit itself. This segmentation allows the correction mechanism to be added without significantly complicating the core pixel circuit structure, maintaining relative simplicity while improving accuracy.
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 enhances the reliability of image data by correcting output values and storing programs to manage transistor characteristics, thereby maintaining data accuracy and consistency in the face of radiation-induced changes.
Implementation Method 1
The pixel circuit includes a light-receiving element
Implementation Method 2
One embodiment of the present invention relates to an imaging device including a scintillator
Data Source
AI summary
Provided is an imaging device that can correct an output value of a pixel circuit. The imaging device includes a pixel circuit, a current detection circuit, an A/D converter, one or more memory circuit portions, and an arithmetic circuit portion. The pixel circuit includes a transistor, a charge accumulation portion, and a light-receiving element. The memory circuit portion includes a first look-up table, a second look-up table, and a region where image data output from the arithmetic circuit portion is stored. The first look-up table stores data of potentials of the charge accumulation portion, which depends on the intensity of light. The second look-up table stores output data of the transistor, which depends on the potentials of the charge accumulation portion.