Multi Mirror Passive Radiation Detector Shadowing
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Solution Overview
Problem
Existing motion detectors face challenges in achieving uniform sensitivity and focal length flexibility across detection zones, leading to shadowing effects and reduced immunity to disturbance sources, particularly in compact designs with mirror optics.
Innovation Solution
The use of dedicated mirror pairs, where one mirror is concave and the other substantially flat, prevents radiation from one detection zone from being reflected onto the sensor along with other zones, allowing for improved spatial arrangement and reduced shadowing, while maintaining high sensitivity and uniformity across zones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple mirrors are used to create multiple detection zones, then the detection area is expanded, but shadowing effects occur between mirrors reducing sensitivity uniformity
Solution Approach 1:
The detection area is divided into multiple independent detection zones, each served by its own dedicated mirror pair. This segmentation prevents cross-interference between zones while maintaining uniform sensitivity across all areas.
Solution Approach 2:
Each detection zone has its own intermediary mirror pair that independently channels radiation from that specific zone to the sensor, preventing shadowing effects from other zones while maintaining detection uniformity.
2Length of stationary object
If focal length is reduced to make detector more compact, then detector thickness is reduced, but sensitivity and frequency response uniformity deteriorate
Solution Approach 1:
Each mirror pair is specifically designed with local optical properties optimized for its detection zone. The mirrors can have different curvatures and focal lengths tailored to their specific zones, allowing compact overall design while maintaining uniform sensitivity across all zones.
Solution Approach 2:
The optical parameters (focal length, curvature) of each mirror pair are independently adjustable to optimize performance for different detection zones while keeping the overall detector compact. This allows each zone to have optimal parameters without requiring a large overall focal length.
3Reliability
If dedicated mirror pairs are used for each detection zone, then sensitivity uniformity is improved, but device complexity increases
Solution Approach 1:
Multiple mirror pairs are integrated into a single compact detector housing with a shared sensor platform. The mirrors are arranged in a space-efficient configuration that provides dedicated zones for each mirror pair while maintaining overall system compactness and manageable complexity.
4Area of stationary object
If mirrors are positioned to maximize detection zone coverage, then detection area is expanded, but shadowing effects from mirrors increase
Solution Approach 1:
The detection space is segmented into distinct zones, each with its own dedicated mirror pair positioned to serve only that zone. This prevents mirrors from casting shadows into other detection zones while maximizing overall coverage area.
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 detectors to achieve homogeneous sensitivity and frequency response across a large area, from the floor to 12 meters, with a compact thickness of less than 3 centimeters, and potentially up to 18 meters, while minimizing shadowing effects and optimizing mirror placement.
Implementation Method 1
mirrors (111-117, 121-125, 200, 221, 225, 231, 232) that are shaped and mounted in the housing for reflecting onto the sensor radiation from outside detection zones
Data Source
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AI summary
A detector, comprising a housing with at least one window for allowing radiation to enter, at least one sensor (1,2) for sensing entered radiation, a unit for processing sensor signals, and mirrors that are shaped and mounted in the housing for reflecting onto the sensor radiation from outside detection zones better than radiation from elsewhere, wherein linked mirrors reflect radiation from a detection zone consecutively and each mirror in at least one linked pair is shaped and mounted in the housing so as to prevent it from reflecting radiation from another detection zone in sequence with other mirrors onto the sensor, thus optically isolating the pair from other mirrors.