Photoelectric Conversion Control to Reduce Avalanche Photodiode Crosstalk
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Solution Overview
Problem
Existing photoelectric conversion apparatuses face challenges in accurately counting photons under varying illuminance conditions, particularly due to crosstalk between pixels caused by flaw pixels, which degrades image quality, especially in low-illuminance environments.
Innovation Solution
The apparatus employs a control signal with adjustable timing to manage the operation of the switch connected to the avalanche photodiode, reducing crosstalk by controlling the recharge frequency of the photodiode, and combining images captured in different frames to enhance image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of control signals is increased to improve photon counting accuracy, then measurement precision is improved, but device complexity and power consumption increase
Solution Approach 1:
The patent applies dynamics by making the number of control signals variable rather than fixed. The control signal generation unit dynamically adjusts the number of control signals based on detected photon counts - using more signals when photon counts are low to improve accuracy, and fewer signals when photon counts are high to reduce complexity and power consumption.
Solution Approach 2:
The patent changes the parameter of control signal quantity adaptively. By varying the number of control signals according to illumination conditions and photon detection results, the system optimizes the balance between measurement precision and device complexity for different operating scenarios.
2Productivity
If the number of control signals is increased to capture more photons, then productivity is improved, but power consumption increases
Solution Approach 1:
The system dynamically adjusts power consumption by varying the number of control signals based on real-time photon detection needs. In low-light conditions, more control signals are used to maximize photon detection efficiency. In bright conditions, fewer signals suffice, reducing power consumption while maintaining productivity.
Solution Approach 2:
The patent changes operational parameters (number of control signals) adaptively to optimize the trade-off between productivity and power consumption, allowing the system to achieve high photon detection efficiency when needed while conserving energy when illumination is sufficient.
3Measurement precision
If image combining is performed to improve image quality, then measurement precision is improved, but processing time increases
Solution Approach 1:
The patent applies partial action by performing image combining selectively rather than always. Image combining is applied to specific frames where it provides the most benefit, such as low-illuminance frames, while other frames may be processed more quickly without combining, thus reducing overall processing time while still improving image quality where needed.
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 effectively reduces crosstalk and improves image quality by accurately counting photons across different illuminance levels, ensuring high-quality image capture even in low-light conditions.
Implementation Method 1
a pixel includes an avalanche photodiode (APD)... perform image capturing using avalanche light emission
Data Source
AI summary
A photoelectric conversion apparatus includes a processing circuit, and a memory that stores a computer-readable instruction for causing, when executed by the processing circuit, the photoelectric conversion apparatus to generate control signals for controlling an operation of an image capturing unit configured to perform image capturing using avalanche light emission, control a first generation unit to generate control signals of a first frame and a second frame, wherein a number of the control signals during an exposure period of the second frame is smaller than a number of the control signals during an exposure period of the first frame, acquire an output of the first frame captured by the image capturing unit and an output of the second frame captured by the image capturing unit, and generate an image based on the output of the first frame and the output of the second frame.