Photodetector Characterization Using Encoded LED Step Signals
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Solution Overview
Problem
Flow cytometers face challenges in accurately calibrating photodetector response to light due to variations among different types of photodetectors and non-linear characteristics, requiring conventional methods that use calibration beads, which are time-consuming and may not be suitable for real-time adjustments.
Innovation Solution
The use of controlled LED flashes in combination with data stream encoding to determine and calibrate photodetector parameters in real-time without the need for calibration beads, by detecting step signals indicating changes in light intensity, frequency, or spectrum, and integrating data signals over predetermined time intervals to calculate detector sensitivity and gain adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional calibration methods using fluorescent beads are used, then photodetector response can be characterized, but the process is time-consuming and requires user intervention
Solution Approach 1:
The patent replaces the mechanical/manual process of calibration with an automated optical system. LED flashers emit controlled light pulses that are detected by the photodetector, and a processor automatically analyzes the response signals to generate calibration data, eliminating the need for manual bead-based calibration procedures
Solution Approach 2:
The system performs self-calibration by using its own components (LED flashers and photodetector) to characterize the photodetector response. The processor automatically processes the detection signals and generates calibration parameters without requiring external calibration beads or user intervention, enabling the system to calibrate itself
2Productivity
If LED flashers are used for calibration, then real-time calibration is enabled, but data reliability may be compromised without proper encoding
Solution Approach 1:
The patent introduces data stream encoding as an intermediary mechanism between the LED flashers and the photodetector. The encoder modulates the LED flash signals with identification codes, and the processor decodes these signals to verify data integrity, ensuring reliable real-time calibration without compromising accuracy
Solution Approach 2:
The system implements feedback through the encoding and decoding process. The processor compares the decoded identification codes with expected values to verify signal integrity, and only accepts calibration data when verification succeeds, ensuring reliability while maintaining real-time operation
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 provides more precise and consistent characterization of photodetector response and sensitivity, enabling real-time calibration without user intervention and improving the reliability of flow cytometry results.
Implementation Method 1
detecting light from a light source with a photodetector
Data Source
AI summary
Aspects of the present disclosure include methods for determining a parameter of a photodetector (e.g., a photodetector in a particle analyzer). Methods according to certain embodiments include detecting light from a light source with a photodetector for a first predetermined time interval, detecting a step signal with the photodetector, the step signal indicating a change in a parameter of the light source or a parameter of the photodetector, detecting light from the light source for a second predetermined time interval, integrating data signals over the first predetermined time interval and the second predetermined time interval and determining one or more parameters of the photodetector based on the integrated data signals. Systems (e.g., particle analyzers) having a light source and a photodetector for practicing the subject methods are also described. Non-transitory computer readable storage medium having instructions stored thereon for determining a parameter of a photodetector according to the subject methods is also provided.