Particulate Matter Sensor Stacked Housing Design
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Solution Overview
Problem
Existing particulate matter sensors face challenges in efficiently analyzing small particle numbers and sizes within a reasonable measurement time, particularly in compact designs where mechanical alignment tolerances and optical signal interference are concerns.
Innovation Solution
The design of a compact particulate matter sensor module that focuses fluid into a small region for interaction with light, using a housing with a light reflection chamber, particle-light interaction chamber, and light trap chamber, with tapered inner walls and a reflective surface to minimize optical interference and enhance light detection, allowing for efficient counting and sizing of particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the sensor module is made compact, then the device size is reduced, but the measurement time increases and particle analysis efficiency decreases
Solution Approach 1:
The housing is divided into multiple sections (first section, second section, third section) that define distinct functional chambers (light reflection chamber, particle-light interaction chamber, light trap chamber). This segmentation allows each chamber to be optimized for its specific function while maintaining a compact overall structure, enabling efficient particle analysis within a small volume.
Solution Approach 2:
The patent uses a stacked configuration of housing sections arranged in multiple dimensions rather than a single linear arrangement. The first, second, and third sections are stacked to create vertical layering of functional chambers, effectively utilizing three-dimensional space to pack more functionality into a smaller footprint while maintaining adequate light paths and fluid flow channels.
2Volume of moving object
If the housing sections are tightly stacked to reduce size, then mechanical alignment tolerances become more critical, but manufacturing complexity increases
Solution Approach 1:
Multiple functional chambers (light reflection chamber, particle-light interaction chamber, light trap chamber) are integrated within a stacked housing structure where the first, second, and third sections collectively define all chambers. This merging of functions into a unified stacked architecture reduces the number of separate components and assembly steps, thereby reducing cumulative alignment tolerance requirements while maintaining compact size.
Solution Approach 2:
The housing sections serve multiple functions simultaneously: the first section defines both the light reflection chamber and fluid inlet, the second section defines the particle-light interaction chamber and contains the reflective surface, and the third section defines the light trap chamber. This multi-functionality reduces the number of separate components needed, simplifying manufacturing and reducing alignment tolerance requirements.
3Measurement precision
If the light path is made longer to improve particle detection, then the device size increases, but compact design is compromised
Solution Approach 1:
A reflective surface is incorporated into the second housing section to redirect light through the particle-light interaction chamber. This allows the light to follow a curved or reflected path rather than a straight line, effectively increasing the light-particle interaction distance within the compact vertical space defined by the stacked housing sections, thereby improving detection accuracy without increasing overall device size.
Solution Approach 2:
The light path is extended by utilizing the vertical dimension created by the stacked housing sections. The light travels through the first section, reflects off the surface in the second section, and continues through the particle-light interaction chamber in the vertical stack arrangement. This three-dimensional light path configuration allows for longer interaction distances within a compact footprint.
4Quantity of substance
If the fluid flow conduit is extended to pump more fluid, then the device size increases, but particle sampling efficiency decreases
Solution Approach 1:
The fluid flow path is segmented into distinct portions: a fluid inlet in the first section that feeds directly into the particle-light interaction chamber in the second section. This segmentation allows the fluid to be focused through a controlled path, ensuring that all or most of the pumped fluid passes through the interaction region, thereby maximizing the quantity of fluid analyzed within the compact stacked structure.
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 configuration enables effective analysis of all or most pumped fluid, achieving accurate particle counting and sizing within a reasonable time, even in compact forms, by reducing mechanical alignment dependencies and minimizing optical signal interference.
Implementation Method 1
A reflective surface is provided in the light reflection chamber. The reflective surface is configured to reflect light toward the particle-light interaction chamber where the light can interact with particles in a fluid flowing in the fluid flow conduit.
Implementation Method 2
The first section has a second aperture through which light scattered in the particle-light interaction chamber as a result of interaction with one or more of the particles can pass for sensing by the detector.
Data Source
AI summary
A particulate matter sensor module includes a light source and a light detector mounted on a substrate. A housing is attached to the substrate and includes first and second sections attached to one another in a stack over the substrate such that the first section is disposed between the substrate and the second section. The first and second sections, in combination, define a light reflection chamber, a fluid flow conduit, a particle-light interaction chamber, and a light trap chamber. The first section has a first aperture through which light emitted by the light source can pass to a reflective surface within the light reflection chamber. The reflective surface is configured to reflect the light toward the particle-light interaction chamber where the light can interact with particles in a fluid flowing in the fluid flow conduit. The first section has a second aperture through which light scattered in the particle-light interaction chamber as a result of interaction with one or more of the particles can pass for sensing by the detector. The fluid flow conduit includes a fluid inlet portion having an end coupled directly to the particle-light interaction chamber.