Infrared Motion Detector Radial Movement Accuracy

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Solution Overview

Problem

Passive infrared motion detectors have differing detection accuracies for radial and tangential movements, with radial movements often being harder to detect due to the size of the perceived object and typical sensor resolutions.

Innovation Solution

A motion detection device with multiple infrared sensors and an optical element that divides the detection area into a long-range and a close-range area, using a mirror or lens to ensure that objects in the close range are imaged on at least two sensors, allowing for improved detection of radial movements by generating distinct signal responses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a single infrared sensor is used for motion detection, then the device structure is simple, but the detection accuracy for radial movements is poor

Engineering Contradiction:
Improvedetection accuracy for radial movementsVSAvoidsensor configuration
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The detection area is segmented into multiple zones using an optical element (lens or mirror) that divides the field of view into a first detection area and a second detection area. The first infrared sensor detects movements in the first detection area while the second infrared sensor detects movements in the second detection area, allowing radial movements to be detected through multiple segmented zones rather than a single sensor.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If the detection range is divided into multiple areas with separate sensors, then radial movement detection is improved, but the device complexity increases

Engineering Contradiction:
Improvedetection accuracy for radial and tangential movementsVSAvoidoptical element and sensor arrangement
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

An optical element (lens or mirror) is introduced as an intermediary component to divide the detection area into multiple zones. This optical element redirects infrared radiation from different spatial areas to appropriate sensors, enabling the system to detect radial movements effectively without requiring complex sensor arrangements or processing.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If infrared radiation is directed to multiple sensors through an optical element, then detection precision is enhanced, but the device complexity increases

Engineering Contradiction:
Improveoverall detection precisionVSAvoidoptical system configuration
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The optical system segments the incoming infrared radiation into distinct spatial zones using a lens or mirror, directing each zone to a dedicated infrared sensor. This segmentation allows the system to maintain high detection precision by analyzing temperature changes in multiple separate detection areas simultaneously, rather than relying on a single sensor with complex processing.

Inventive Principle:
Principle #1Segmentation

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 enhances the detection accuracy for radial movements to match that of tangential movements, enabling the detection of smaller objects and slight fluctuations in infrared radiation, thereby improving overall detection precision.

Implementation Method 1

The optical element directs IR radiation from the detection area of the motion detection device onto the IR sensors

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

The optical element directs IR radiation from the detection area of the motion detection device onto the IR sensors

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 3

Passive infrared sensors (PIR sensors) are used as motion detectors... detect the heat radiated by an object in the sensor's field of view in the form of infrared radiation

Methodology Applied
Scientific EffectInfrared radiation detection: Infrared Radiation

Data Source

PatentEP4118405B1Infrared motion detector
Publication Date: 2024.05.01 STEINEL
  • EP4118405B1 patent drawingFigure 1A~1C
  • EP4118405B1 patent drawingFigure 2A~2B
  • EP4118405B1 patent drawingFigure 3A~3D

AI summary

A motion-detecting device (100) comprises a plurality of infrared sensors (110) for detecting motion and an optical element (120), which is suitable for directing infrared radiation incident on the motion-detecting device (100) at the infrared sensors (110). The optical element (120) divides a detection region (130) of the motion-sensing device (100) into a far region (132) and a near region (136). The fields of vision of the infrared sensors (110) in the far region (132) are spatially separated from each other, while fields of vision of at least two infrared sensors (110) in the near region (136) overlap.