Multi-Point Beam Detector Misalignment Tolerance
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Solution Overview
Problem
Beam detectors face challenges such as false positives due to foreign objects, alignment issues during installation, and interference from reflective surfaces, which can lead to misalignment and false alarms. Additionally, battery-powered units often require manual activation, which can be overlooked during installation, and exposed optical surfaces can become contaminated, causing signal degradation.
Innovation Solution
The proposed system uses a receiver with a wide field of view and imaging optics to independently measure light intensity at multiple points, allowing for misalignment tolerance and reduced calibration requirements. It also employs dual wavelength light sources, where the relative change in received light at different wavelengths helps distinguish between particle presence and other obstructions. Furthermore, the system includes mechanisms to compensate for optical surface contamination and to simplify the installation process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional beam detectors are used with narrow field of view, then alignment precision is improved, but ease of operation deteriorates due to careful alignment requirements during installation
Solution Approach 1:
The patent transitions from a single-point detection approach to a multi-point array detection approach. The receiver includes an array of light sensors that can independently measure light intensity at multiple points across the beam profile, adding spatial dimensionality to the detection process. This allows the system to tolerate misalignment by distributing measurements across multiple sensor elements rather than relying on a single critical alignment point.
Solution Approach 2:
The receiver is designed to perform multiple functions: it can detect particle obscuration, characterize beam profile, determine alignment status, and distinguish between different types of obstructions. By integrating these functions into a single multi-point array receiver, the system eliminates the need for separate alignment tools and procedures, simplifying installation and operation.
2Device complexity
If single wavelength light sources are used, then device complexity is reduced, but reliability deteriorates due to inability to distinguish between particle presence and foreign objects
Solution Approach 1:
The system uses light sources emitting at different wavelengths (e.g., infrared and ultraviolet) to probe the monitored area. Smoke particles and foreign objects attenuate these different wavelengths differently, providing a spectral signature that enables discrimination between particle types. This parameter change from single-wavelength to multi-wavelength detection resolves the ambiguity in identifying the nature of obstructions.
Solution Approach 2:
The controller acts as an intermediary that receives light intensity measurements from the multi-point array receiver at different wavelengths and processes this data to distinguish between smoke particles and foreign objects. By analyzing the pattern of attenuation across multiple wavelengths and sensor points, the controller can identify characteristic signatures of different particle types, improving detection reliability.
3Ease of manufacture
If exposed optical surfaces are used, then ease of manufacture is improved, but reliability deteriorates due to contamination causing signal degradation
Solution Approach 1:
The multi-point array receiver continuously monitors light intensity across multiple sensor elements. By analyzing changes in the beam profile and intensity distribution over time, the system can detect contamination on optical surfaces. The controller uses this feedback information to distinguish between signal changes caused by contamination versus those caused by particle obscuration, maintaining detection accuracy despite surface degradation.
Solution Approach 2:
The system performs preliminary characterization of the beam profile and light intensity distribution during normal operation. This baseline information is stored and used for comparison during subsequent measurements. By having this preliminary reference data, the system can quickly identify deviations caused by contamination or particle presence without requiring complex real-time analysis, maintaining reliability even with exposed optical surfaces.
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 system effectively reduces false alarms by distinguishing between particle presence and other obstructions, minimizes the need for precise alignment during installation, and maintains sensitivity over time despite optical surface contamination. It also simplifies the activation of battery-powered units and reduces installation costs.
Implementation Method 1
The target 36, e.g. a corner cube reflects incident light 40, resulting in reflected light 32 being returned to receiver 34
Implementation Method 2
the receiver 34 has a wide field of view and has the ability to independently measure light at a wide range of points within this field of view
Implementation Method 3
If particulate matter enters the monitored area 16, it will attenuate the incident light 18 and reflected light 20 and cause the amount of light received at the light source and detector 12 to diminish
Data Source
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AI summary
A beam detector (10) including a light source (32), a receiver (34), and a target (36), acting in cooperation to detect particles in a monitored area (38). The target (36), reflects incident light (40), resulting in reflected light (32) being returned to receiver (34). The receiver (34) is a receiver is capable of recording and reporting light intensity at a plurality of points across its field of view. In the preferred form the detector (10) emits a first light beam (3614) in a first wavelength band; a second light beam (3618) in a second wavelength band; and a third light beam (3616) in a third wavelength band, wherein the first and second wavelengths bands are substantially equal and are different to the third wavelength band.