Avalanche Photodiode Count Cutoff for Stable Photon Detection
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Solution Overview
Problem
Photon-count type photoelectric conversion devices face issues with high power consumption and unstable circuit operations due to the need for frequent photon detection operations, leading to unnecessary power usage and potential voltage drops, especially when the upper count limit is reached before the exposure period ends.
Innovation Solution
A photoelectric conversion device incorporating an avalanche multiplying photodiode with a control unit that manages the applied voltage to stop avalanche current generation when a predetermined count value is reached, reducing power consumption and stabilizing circuit operations by controlling the cathode voltage of the photodiode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If photon detection operations continue until the end of the exposure period even after the upper count limit is reached, then the counting function is maintained, but power consumption increases unnecessarily
Solution Approach 1:
The invention applies preliminary anti-action by stopping the avalanche current generation when the upper count limit is reached, thereby preventing unnecessary power consumption that would occur if detection operations continued until the end of the exposure period. The control unit proactively terminates the high-power avalanche mode before the exposure period ends, counteracting the tendency toward continuous operation.
Solution Approach 2:
The invention implements partial action by performing photon detection operations only until the upper count limit is reached, rather than continuing operations for the full exposure period. This partial operation approach achieves the counting function while avoiding excessive power consumption that would result from completing the full exposure period operations.
2Productivity
If the frequency of photon detection operations is increased, then the counting capability is improved, but the power supply voltage drops due to increased current and interconnection resistance
Solution Approach 1:
The control unit applies preliminary anti-action by stopping the avalanche current generation when the upper count limit is reached, thereby preventing the increase in detection operation frequency that would cause excessive current flow and voltage drops. This proactive termination maintains circuit operation stability by avoiding the harmful effects of high-frequency operations.
Solution Approach 2:
The invention converts the potential harm of continuous high-frequency detection operations into a benefit by using the upper count limit as a trigger to stop operations. This transforms what would be a harmful continuous operation into a beneficial controlled operation that achieves counting capability while maintaining voltage stability.
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 solution reduces power consumption and improves circuit stability by stopping avalanche current generation when the count value reaches a set threshold, minimizing unnecessary operations and voltage drops.
Implementation Method 1
an avalanche multiplying photodiode
Data Source
AI summary
A photoelectric conversion device includes an avalanche multiplying photodiode, a signal generation unit that includes a control unit configured to control an applied voltage to the photodiode and generates a photon detection pulse based on an output generated by incidence of a photon to the photodiode, and a counter that counts the photon detection pulse output from the signal generation unit, and the counter outputs a setting value detection signal when a count value of the photon detection pulse reaches a predetermined setting value, and in response to receiving the setting value detection signal, the control unit controls the applied voltage to the photodiode so as to stop generation of an avalanche current in the photodiode.