Particle Sensor Stray Light Attenuation via Aperture Design
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Solution Overview
Problem
Scattered light particle sensors face detection accuracy issues due to stray light noise caused by the high focusing ability of reflectors, which receive leaked light as unwanted illumination.
Innovation Solution
A particle sensor design incorporating a light projector, a light receiver, a first reflector that reflects and guides scattered light, and a light attenuator with a smaller third aperture than the second aperture, to reduce noise from stray light by attenuating unwanted light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a reflector is used to improve detection efficiency by reflecting and focusing scattered light onto the light receiver, then detection efficiency is improved, but noise is generated when leaked light is received as stray light
Solution Approach 1:
A light attenuator is introduced as an intermediary component between the light receiver and the reflector. This attenuator selectively reduces the intensity of stray light (unwanted light) while allowing scattered light (useful light) to pass through, thereby mediating between the conflicting requirements of maintaining high detection efficiency and reducing noise from leaked light
Solution Approach 2:
The light attenuator applies different optical properties to different regions of light paths. It is designed to attenuate light in specific directions (stray light paths) while maintaining high transmission for scattered light paths, creating local quality differences in light transmission based on the direction and origin of the light
2Object-generated harmful factors
If a light trap is disposed to oppose the light projector or light receiver to reduce stray light, then stray light is reduced, but detection accuracy decreases due to decreased light intensity from the reflector
Solution Approach 1:
The light attenuator serves as a selective intermediary that differentiates between useful scattered light and harmful stray light. Unlike a light trap that blocks all light uniformly, the attenuator is positioned and designed to attenuate only the stray light components while preserving the scattered light signal, thus maintaining detection accuracy while reducing stray light interference
Solution Approach 2:
The light attenuator changes the intensity parameter of light selectively based on its origin and direction. It applies different attenuation levels to different light paths, reducing the intensity of stray light while maintaining the intensity of scattered light, thereby resolving the contradiction between stray light reduction and detection accuracy
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 reduces noise generated by stray light, enhancing detection accuracy and efficiency in particle sensors by minimizing unwanted light reception.
Implementation Method 1
a first reflector that reflects and guides the scattered light to the light receiver
Implementation Method 2
a light attenuator for attenuating light that exits the first reflector
Implementation Method 3
a light projector that projects light to a detection area
Implementation Method 4
detects particles in the gas by detecting light scattered by the particles
Data Source
AI summary
A particle sensor is provided. The particle sensor includes a light projector that projects light to a detection area. A light receiver receives scattered light. The scattered light is light from the light projector that has been scattered by particles in the detection area. A first reflector reflects the scattered light to the light receiver. A light attenuator attenuates stray light that exits the first reflector. The first reflector includes a first aperture that introduces the light from the light projector into an interior of the first reflector and a second aperture that exits the stray light from the first reflector. The light attenuator includes a third aperture through which the stray light that exits the first reflector passes. An aperture area of the third aperture is smaller than an aperture area of the second aperture.