Optical Proximity Sensor for NVG Automatic On-Off Control

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Solution Overview

Problem

Night vision goggles (NVGs) often inadvertently turn off when the user is not looking in a level direction or during movements like rolling or tumbling, and the magnetic switch mechanism can be noisy, potentially giving away the user's position.

Innovation Solution

A night vision device equipped with a proximity sensor that uses an infrared emitter and detector to maintain the device in the 'ON' position when in use and automatically switch to 'OFF' when not in use, ensuring continuous operation regardless of the user's orientation and minimizing noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If a magnetic switch mechanism is used to turn the NVG on/off, then the device can be automatically controlled based on position, but the magnet may inadvertently slide to the OFF position during head movements or rolling, rendering the NVG inoperable at inopportune times

Engineering Contradiction:

Improveautomatic on/off controlVSAvoidcontinuous operation

Core Design Contradiction:

Extent of automationVSReliability

Solution Approach 1:

The patent replaces the mechanical magnetic switch mechanism with an optical proximity sensor system. The proximity sensor uses infrared or optical fields to detect the user's presence and control NVG operation, eliminating the mechanical sliding magnet that causes inadvertent shutdowns during head movements. This substitution of mechanical detection with optical detection resolves the reliability issue while maintaining automatic control.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Extent of automation

If a magnetic switch mechanism is used to turn the NVG on/off, then the device can be automatically controlled, but the magnet slides within its housing with an audible click that may disturb soldiers fearful of generating sound

Engineering Contradiction:

Improveautomatic on/off controlVSAvoidaudible noise

Core Design Contradiction:

Extent of automationVSObject-generated harmful factors

Solution Approach 1:

The patent eliminates the mechanical magnetic switch that produces audible clicking sounds by replacing it with an optical proximity sensor system. The proximity sensor detects user presence optically and controls the NVG state without any mechanical movement or audible noise, thus removing the harmful acoustic signature while preserving automatic operation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If the NVG is mounted on a helmet and movable between operational and stowed positions, then the device can be positioned for use or stored securely, but in the stowed position the eyepieces are directed outward allowing enemy to see the green glow and give away the soldier's position

Engineering Contradiction:

Improvepositioning flexibilityVSAvoidvisibility of green glow

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent employs a proximity sensor that provides feedback about the user's presence and the device's operational state. When the sensor detects that the NVG is in the stowed position (away from the user's face), it automatically triggers the shutdown sequence, turning off the intensifier tube and eliminating the green glow. This feedback mechanism ensures the device remains invisible when not in use while maintaining positioning flexibility.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The proximity sensor system performs preliminary detection of the device's position relative to the user's face. Before the user even moves the NVG to the stowed position, the sensor anticipates the upcoming state change and prepares the shutdown sequence, ensuring the green glow is turned off promptly when the device is moved away from the user's eyes, thus preventing visibility to enemies.

Inventive Principle:

Principle #10Preliminary action

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 proximity sensor ensures the NVG remains operational during various orientations and movements without generating audible clicks, maintaining stealth and functionality.

Implementation Method 1

a proximity sensor mounted on the housing... moving the proximity sensor to a close proximity of a body to activate the intensifier tube

Methodology Applied

Scientific EffectProximity detection:

Implementation Method 2

The NVG intensifies the available low-level ambient light, and provides an image having a generally greenish glow

Methodology Applied

Scientific EffectLight intensification:

Data Source

PatentUS7315254B2Proximity detector for night vision goggles shut-off

Publication Date: 2008.01.01 ELBIT SYSTEMS OF AMERICA LLC

AI summary

A night vision device is disclosed. The device includes a housing that houses an intensifier tube and a proximity sensor mounted on the housing. An ON/OFF switch is operatively coupled to the intensifier tube and to the proximity sensor such that operation of the ON/OFF switch to the “ON” position automatically activates the proximity sensor. A method of operating the night vision device with the proximity sensor is also disclosed.