Flow Cytometer Dual Photodetection for Wide Dynamic Range
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Solution Overview
Problem
Semiconductor photodetection elements face challenges in achieving a wide dynamic range for applications like flow cytometers due to limitations in adjusting light sensitivity and increased chip area and cost when increasing pixel density.
Innovation Solution
A biological sample analyzer employs a dual semiconductor photodetection system with first and second elements to detect and process light signals, utilizing a processing circuit to acquire information from both signals, and a series of photodiodes operating in Geiger mode with reflective stages to enhance dynamic range without increasing chip size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of pixels is increased to extend dynamic range, then the dynamic range is improved, but the chip area increases in proportion to the number of pixels
Solution Approach 1:
The patent implements a nested detection structure where a second photodetection element detects light reflected by a first photodetection element. This creates a hierarchical detection system where the second element captures only the reflected portion, allowing the first element to maintain high sensitivity for dark particles while the second element captures brighter reflected signals, thereby extending the overall dynamic range without increasing the chip area.
2Measurement precision
If the number of pixels is increased to extend dynamic range, then the dynamic range is improved, but the cost increases
Solution Approach 1:
The nested detection architecture allows the system to achieve extended dynamic range using a limited number of photodetection elements. By having the second element detect reflected light from the first element rather than requiring many parallel pixels, the system reduces the total number of pixels needed, thereby lowering manufacturing costs while maintaining wide dynamic range capability.
3Measurement precision
If the pixel size is maintained to preserve quantum efficiency, then the quantum efficiency is improved, but the chip area increases when the number of pixels is increased
Solution Approach 1:
The nested detection system allows each photodetection element to maintain its optimal pixel size for high quantum efficiency. The first element detects direct light with high quantum efficiency, while the second element detects reflected light from the first element. This hierarchical approach eliminates the need to increase pixel count, thereby maintaining quantum efficiency without increasing chip area.
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 extends the dynamic range of light detection, maintaining sensitivity to both dark and bright particles, reducing the likelihood of saturation, and controlling costs by optimizing pixel arrangement and signal processing.
Implementation Method 1
a first semiconductor photodetection element that detects first light generated by irradiation of a biological sample and generates a first signal
Implementation Method 2
a second semiconductor photodetection element that detects second light reflected by the first semiconductor photodetection element among the first light and generates a second signal
Data Source
AI summary
A dynamic range is extended while suppressing an increase in a chip area.A biological sample analyzer of the present disclosure includes: a first semiconductor photodetection element that detects first light generated by irradiation of a biological sample and generates a first signal; a second semiconductor photodetection element that detects second light reflected by the first semiconductor photodetection element among the first light and generates a second signal; and a processing circuit that acquires information regarding the first light on the basis of the first signal and the first signal.