Particle Sensor Temporal Segmentation for Contamination Accuracy
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing particle detection systems face reduced measurement accuracy and reliability due to contamination on optical elements and the measurement chamber, which affects light absorption and scattering, leading to inaccurate particle counts over time.
Innovation Solution
A method using a sensor device with an emitter unit and a photosensitive element inside a measurement chamber, where a reflector is positioned opposite to the sensor device, emitting a first pulse of light with a specified emission direction, and detecting first reflected fractions during a timed window before potential reflections from the chamber, minimizing contamination effects and ensuring accurate particle counting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional photodiode and LED system is used for particle detection, then the system structure is simple, but measurement accuracy deteriorates due to contamination on optical elements
Solution Approach 1:
The patent segments the detection process into multiple time windows: a first time window for detecting particle scattering signals and a second time window for detecting contamination signals. This temporal segmentation allows the system to distinguish between particle signals and contamination interference, improving measurement precision without adding complex hardware
Solution Approach 2:
The system uses periodic pulsed illumination with alternating measurement phases. During the first time window, particle scattering is measured; during the second time window, contamination effects are measured. This periodic action enables the system to compensate for contamination by comparing signals from different time periods, maintaining high measurement accuracy
2Reliability
If the measurement chamber is used for extended periods, then productivity is improved, but reliability deteriorates due to accumulating contamination
Solution Approach 1:
The system implements feedback by using the contamination signal detected in the second time window to compensate for the particle measurement in the first time window. The evaluation unit calculates compensation factors based on the contamination signal and applies these to correct the particle detection results, maintaining reliability over extended operational periods
Solution Approach 2:
The system performs self-diagnosis and self-compensation by automatically detecting contamination effects and correcting measurements without external intervention. The dual time window approach enables the system to monitor its own degradation and compensate for it, ensuring long-term reliable operation
3Measurement precision
If contamination accumulates on optical elements, then the system can operate continuously, but measurement precision deteriorates due to light absorption
Solution Approach 1:
The system performs preliminary contamination assessment by measuring the contamination signal in the second time window before final particle quantification. This preliminary action allows the system to pre-calculate compensation factors and apply them to the particle measurement, ensuring accuracy even as contamination accumulates over time
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 enhances measurement accuracy and long-term reliability by avoiding contamination-induced light absorption and scattering, allowing for precise determination of particle amounts in the medium, even in the presence of contamination on the reflector and cover.
Implementation Method 1
more or less light emitted by the LED is scattered by the particles and received by the photodiode
Implementation Method 2
first fractions of the first pulse being reflected by particles in a medium present in the measurement chamber are detected by a photosensitive element
Implementation Method 3
a signal representing the measured amount of particles in the medium may get tampered for example by light absorption due to the contamination on the optical elements
Data Source
Figure 1A~3
Figure 4~5
AI summary
A method for detecting particles comprises emitting by an emitter unit (EU) a first pulse (P1) of light into a measurement chamber (MC) in a specified emission direction, detecting first reflected fractions (RF1) by a photosensitive element during a first time window (TW1) and determining an amount of particles depending on the detection of the first reflected fractions (RF1). A path with minimum length for a light ray being emitted by the emitter unit (EU), reflected from a reflector (R) and detected by the photosensitive element is defined by the emission direction and by a mutual arrangement of the reflector (R), the emitter unit (EU) and the photosensitive element. A difference between a starting time of the first pulse (P1) and an end time of the first time window (TW1) is smaller than a time-of-flight for light propagating along the path with minimum length.