Laser Sensor Module Reducing Particle Density Multiple Counts
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Solution Overview
Problem
Existing laser sensor technologies for particle density detection suffer from multiple counting of particles due to uncontrolled air streams and vortices, leading to inaccurate particle density measurements.
Innovation Solution
A laser sensor module with an array of lasers and advanced evaluation electronics, including a controller, is used to reduce multiple counts by interrupting detection periods and employing self-mixing interference signals, along with focusing optics to enhance signal strength and reduce noise, allowing for precise particle counting and estimation of air movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If continuous laser detection is used in uncontrolled air streams, then detection coverage is maximized, but multiple counting of particles occurs due to vortices circulating particles in and out of the measurement volume
Solution Approach 1:
The patent applies periodic action by interrupting the laser detection at regular intervals to allow air refreshment. The laser is switched off during predetermined time periods, enabling particles to be cleared from the measurement volume through air flow, thereby preventing multiple counting while maintaining detection coverage during active periods.
Solution Approach 2:
The patent implements preliminary action by proactively interrupting detection before multiple counting can occur. The controller is configured to switch off the laser during predetermined time periods based on expected particle circulation patterns, preventing the harmful effect of multiple counts before it happens.
2Measurement precision
If air refreshment is enabled by interrupting measurement, then multiple counts are reduced, but detection time increases and productivity decreases
Solution Approach 1:
The patent applies partial action by implementing intermittent rather than continuous interruption of detection. The laser is switched off during brief predetermined time periods sufficient to clear particles from the measurement volume, then switched back on to resume detection. This partial interruption approach achieves the necessary air refreshment while minimizing loss of detection 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
The solution improves the accuracy of particle density detection by minimizing double counts and providing reliable estimates of particle movement, enhancing detection speed and accuracy in various applications, including air pollution monitoring and industrial settings.
Implementation Method 1
The at least one first detector is adapted to detect a first self-mixing interference signal of an optical wave within a first laser cavity of the first laser. The first self-mixing interference signal is caused by first reflected laser light reentering the first laser cavity
Data Source
AI summary
The invention describes a laser sensor module (100) for particle density detection. The laser sensor module (100) comprising at least one first laser (110), at least one first detector (120) and at least one electrical driver (130). The first laser (110) is adapted to emit first laser light in reaction to signals provided by the at least one electrical driver (130). The at least one first detector (120) is adapted to detect a first self-mixing interference signal of an optical wave within a first laser cavity of the first laser (110). The first self-mixing interference signal is caused by first reflected laser light reentering the first laser cavity, the first reflected laser light being reflected by a particle receiving at least a part of the first laser light. The laser sensor module (100) is adapted to reduce multiple counts of the particle. The invention further describes a related method and computer program product.