Door Window Sensor Using Infrared Radiation Detection

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Solution Overview

Problem

Conventional sensors for detecting the secure state of doors and windows, such as magnetic sensors, are inadequate as they can be affected by long-term changes in geometry and lack sensitivity, necessitating an improved detection method.

Innovation Solution

A sensor assembly utilizing a passive infrared sensor with a lens system that guides ambient infrared radiation differently based on the door or window's state, combined with a capacitive sensor for additional detection, providing a single-piece non-magnetic solution unaffected by geometry changes and enhancing sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If magnetic sensors are used to detect door/window state, then the detection function is provided, but the sensors are affected by long-term changes in geometry and lack sensitivity

Engineering Contradiction:

Improvedetection reliabilityVSAvoiddetection sensitivity

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent replaces magnetic field-based detection with infrared radiation-based detection. The passive infrared sensor detects infrared radiation from the door or window surface, eliminating dependence on magnetic field stability and geometric precision. This substitution of detection physics fundamentally resolves the sensitivity and reliability issues inherent in magnetic sensor systems.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the detection parameter from magnetic field strength to infrared radiation intensity. By measuring the infrared radiation emitted or reflected from the door/window surface, the system achieves detection that is insensitive to geometric changes and provides superior sensitivity, as infrared radiation detection can detect subtle thermal variations and surface properties.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If conventional magnetic sensors are used, then the door/window state can be detected, but the sensors are affected by long-term changes in geometry

Engineering Contradiction:

Improvedetection stabilityVSAvoidgeometric stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent replaces the mechanical/magnetic field-based detection system with an optical/thermal detection system using passive infrared sensors. This substitution eliminates the coupling between detection accuracy and geometric stability, as infrared detection measures thermal radiation properties rather than physical distances or magnetic field geometries, making the system immune to long-term geometric changes.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces infrared radiation as an intermediary between the door/window and the sensor. Instead of directly measuring magnetic fields that are sensitive to geometric changes, the sensor detects infrared radiation that passes through or reflects from the door/window, using this radiation as an intermediary carrier of information that is independent of geometric stability.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 detects the open or closed state of doors and windows with improved sensitivity and durability, unaffected by long-term geometry changes, and provides an additional modality of detection using capacitive sensing.

Implementation Method 1

a passive infrared sensor configured to produce a change in an electrical signal based on a change in infrared radiation incident on the passive infrared sensor

Methodology Applied

Scientific EffectInfrared radiation detection: Infrared Radiation

Implementation Method 2

The lens is configured to receive ambient infrared radiation incident thereon from a first direction, and to direct infrared radiation onto the passive infrared sensor in a second direction different from the first direction

Methodology Applied

Scientific EffectLight refraction and direction: Refraction

Data Source

PatentEP3114657B1Door and window sensors using ambient infrared radiation

Publication Date: 2019.05.29 CARRIER CORP

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AI summary

A sensor assembly for detecting open or closed state in windows and doors includes a passive infrared sensor configured to produce a change in an electrical signal based on a change in infrared radiation incident on the passive infrared sensor. A lens is operatively connected to the passive infrared sensor. At least a portion of the lens is configured to be mounted in an interface between a frame and a door or window mounted to open and close within the frame. The lens is configured to guide ambient infrared radiation to the passive infrared sensor at a first level when the door or window is closed and at a second level when the door or window is open or ajar.