Imaging Element With Intermittent Readout For Radiation Detection
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Solution Overview
Problem
Radiation counters using scintillators and photomultipliers face challenges with high cost, size, weight, magnetic field susceptibility, and environmental sensitivity, while alternatives like avalanche photodiodes and silicon photomultipliers suffer from low output, temperature variations, and high power consumption, and imaging elements struggle with time resolution.
Innovation Solution
An imaging element with a pixel array including non-multiplication and multiplication-type pixels for photoelectric conversion, where signals are intermittently read from non-multiplication pixels and continuously monitored from multiplication pixels, allowing for stable low-voltage operation and improved time resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a photomultiplier is used as the detector, then the energy and number of radiation carriers can be counted accurately, but the device becomes expensive, large, heavy, and susceptible to magnetic fields
Solution Approach 1:
The patent replaces the photomultiplier (a vacuum tube-based device requiring high voltage and producing large signals) with an imaging element consisting of a solid-state image sensor and scintillator. This substitution eliminates the need for complex high-voltage power supplies and magnetic shielding, reducing device size, weight, and cost while maintaining detection accuracy through the solid-state photoelectric conversion process.
2Device complexity
If avalanche photodiodes or silicon photomultipliers are used instead of photomultipliers, then device size and cost are reduced, but output signal becomes weak and temperature sensitivity increases
Solution Approach 1:
The patent combines a scintillator material with a solid-state image sensor to create an integrated imaging element. The scintillator converts incident radiation into visible light photons, which are then detected by the image sensor's photodiodes. This combination produces strong output signals that are less sensitive to temperature variations compared to standalone avalanche photodiodes or silicon photomultipliers, while maintaining compact device size.
3Device complexity
If imaging element is used for radiation detection, then device size is reduced, but time resolution of detection becomes insufficient
Solution Approach 1:
The patent employs a fast-response scintillator material with specific optical properties that enable rapid light emission following radiation interaction. The scintillator's decay time is optimized to be short, allowing the imaging element to resolve successive radiation events with high temporal precision. This parameter optimization of the scintillator material enables the compact imaging element to achieve sufficient time resolution for medical imaging applications.
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
Enables accurate, low-power, and environmentally resistant radiation counting with enhanced time resolution, suitable for applications like PET and flow cytometry.
Implementation Method 1
a first photoelectric conversion section configured to photoelectrically convert incident light
Data Source
AI summary
The present technology relates to an imaging element and a driving method, and an electronic device that enable stable driving with low voltage and low power consumption and furthermore make it possible to ensure a time resolution of detection. A light detector includes a pixel array section including a plurality of first pixels and a second pixel. The first pixel includes a photoelectric conversion section that photoelectrically converts incident light, a floating diffusion section that generates a voltage in accordance with the amount of charge carriers obtained by photoelectric conversion, and a transfer section that transfers charge carriers from the photoelectric conversion section to the floating diffusion section; the readout of a signal is performed intermittently from the first pixel. Further, the output of the second pixel is monitored continuously to detect the incidence of light. The present technology can be applied to a radiation counter.