Particle Detection Sensor Light Trap Wedge Protrusions Stray Light
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Solution Overview
Problem
Conventional scattered light particle detection sensors face issues with erroneous detection due to stray light incident on the light receiving element, which compromises particle detection precision.
Innovation Solution
A particle detection sensor design incorporating a light projection system, a light reception system, and a first light trap with wedge-shaped protrusions that absorb stray light, preventing it from reaching the detection area and improving precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional scattered light particle detection sensor is used, then the structure is simple, but stray light reaches the light receiving element causing erroneous detection
Solution Approach 1:
The light trap is divided into multiple wedge-shaped protrusions arranged in series, each progressively trapping light at different angles. This segmentation allows effective stray light reduction while maintaining a compact structure that doesn't excessively increase device complexity.
Solution Approach 2:
The wedge-shaped protrusions act as intermediary elements between the light source and light receiving element, progressively absorbing and redirecting stray light. These intermediate structures prevent direct stray light paths while allowing the desired scattered light detection function to proceed.
2Measurement precision
If light trap structures are added to prevent stray light, then particle detection precision improves, but the device complexity increases
Solution Approach 1:
The wedge-shaped protrusions are strategically positioned only in regions where stray light paths are most problematic, rather than uniformly throughout the entire optical chamber. This localized approach reduces overall structural complexity while effectively addressing stray light interference at critical locations.
Solution Approach 2:
The light trap uses a three-dimensional arrangement of wedge-shaped protrusions with varying heights and positions, creating multiple light-trapping planes. This dimensional approach efficiently blocks stray light from multiple angles without requiring a proportionally larger overall structure, thus limiting the increase in device complexity.
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 effectively traps stray light, enhancing particle detection precision by reducing noise and improving the signal-to-noise ratio, thereby increasing the accuracy of detecting particles such as dust, pollen, and smoke.
Implementation Method 1
a plurality of wedge-shaped protrusions 115 which are triangular columnar protrusions and each has a base and a tip end... effectively traps stray light
Implementation Method 2
light reception system 130 that receives scattered light, the scattered light being light from the light projection system 120 that has been scattered by a particle in the detection area
Data Source
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AI summary
A particle detection sensor includes: a light projection system (120) that outputs and focuses light on a detection area (DA); a light reception system (130) that receives scattered light, which is light from the light projection system (120) that has been scattered by a particle (2) in the detection area (DA); and a light trap (50A) disposed across the detection area (DA) from the light reception system (130). The light trap (50A) includes: a closed space (51A) having an opening (52A) that opens toward the detection area (DA); and a plurality of wedge-shaped protrusions (115) disposed in the closed space (51A). The plurality of wedge-shaped protrusions (115) each include a base and a tip nd. Among the plurality of wedge-shaped protrusions (115), the farther a wedge-shaped protrusion (115) is located from the detection area (DA), the less a distance between the base and the tip end of the wedge-shaped protrusion is.