Photon Counting Apparatus Counter Saturation Linearity
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Solution Overview
Problem
Conventional photoelectric conversion apparatuses using photon counting face issues with linearity of input/output characteristics due to counter value saturation, leading to inaccurate measurements when one counter reaches its upper limit while the other remains below it.
Innovation Solution
The apparatus includes first and second photoelectric conversion elements, counters, reset units, and an adder with a detection unit that detects when the count value of one counter exceeds a threshold, allowing for resetting and maintaining linearity by continuing counting operations after threshold exceedance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the count value of a counter reaches the upper limit, then the counter cannot accurately represent the number of photons incident, but resetting the counter to initial value causes loss of counting information
Solution Approach 1:
The patent divides the counting system into multiple counters (first counter and second counter) that operate in parallel. When one counter reaches its upper limit, the system can switch to or combine with another counter, ensuring continuous accurate measurement without information loss. This segmentation allows the system to handle photon counts exceeding a single counter's capacity.
Solution Approach 2:
The patent introduces an intermediary mechanism (the detection unit and control logic) that monitors counter states and manages the transition between counters. This intermediary detects when a counter reaches its threshold and coordinates the switching or combining operation, preventing information loss while maintaining measurement accuracy.
2Quantity of substance
If multiple counters are used to extend the measurement range, then the linearity of input/output characteristics degrades when counters are combined, but using a single counter limits the measurement range
Solution Approach 1:
The patent implements feedback through the detection unit that continuously monitors counter values and triggers appropriate actions (switching or combining) based on threshold conditions. This feedback mechanism ensures that counters are used optimally to maintain linearity while extending the effective measurement range through coordinated operation.
Solution Approach 2:
The patent makes the counting system dynamic by allowing switching between different counters based on real-time conditions. Rather than statically combining all counters, the system dynamically selects which counter to use or combine based on current photon flux levels, maintaining linearity across varying measurement conditions.
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 maintains the linearity of input/output characteristics even when counters approach saturation, preventing degradation in signal processing and ensuring accurate photon measurement.
Implementation Method 1
a photoelectric conversion element, a counter circuit that performs a counting operation on a signal output from the photoelectric conversion element
Data Source
AI summary
A photoelectric conversion apparatus includes first and second photoelectric conversion elements, first and second counters, first and second reset units, an adder, and a detection unit. The first counter is configured to perform a counting operation to change a count value based on a signal input from the first photoelectric conversion element. The second counter is configured to perform a counting operation to change a count value based on a signal input from the second photoelectric conversion element. The count value of the first counter and the count value of the second counter are input to the adder. The detection unit is configured to detect an event that the count value of the first counter exceeds a threshold value.