Uncooled IR Night Vision Goggles with Optical Limiting

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Solution Overview

Problem

Current night vision devices are limited to visible wavelengths and near-infrared regions, failing to effectively detect objects at room temperatures, which are primarily emitting in the long-wavelength infrared region.

Innovation Solution

The use of an uncooled IR focal plane array (IRFPA) operating in the 7 to 14 microns wavelength region, combined with electronics and photonics to convert IR signals to visible light for display, within a housing that includes a lens system for focusing and protection mechanisms, allowing for long-wavelength IR detection without visible illumination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If image intensification apparatuses are used to amplify visible light, then visibility in dark conditions is improved, but detection of room-temperature objects in the long-wavelength infrared region is not achieved

Engineering Contradiction:

Improvevisibility in dark conditionsVSAvoiddetection wavelength range

Core Design Contradiction:

Illumination intensityVSAdaptability or versatility

Solution Approach 1:

The patent combines an image intensifier tube for visible light detection with an uncooled infrared focal plane array for long-wavelength infrared detection into a single integrated night vision device. This merging allows the device to simultaneously provide amplified visible light imagery and thermal infrared imagery, resolving the contradiction between improving visibility in dark conditions and expanding detection wavelength range to include room-temperature objects.

Inventive Principle:

Principle #5Merging (Combining)

2Measurement precision

If cooled infrared detectors are used to detect long-wavelength infrared radiation, then detection sensitivity is improved, but device complexity and size increase

Engineering Contradiction:

Improveinfrared detection sensitivityVSAvoiddetector cooling system

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent employs an uncooled infrared focal plane array instead of expensive cooled detectors, accepting slightly reduced sensitivity in exchange for dramatically simplified device architecture. The uncooled detector eliminates the need for complex cryogenic cooling systems, making the device more practical for portable night vision applications while still providing adequate detection of room-temperature objects.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Productivity

If the detector is exposed to sudden increases in object temperature, then detection capability is maintained, but detector damage occurs

Engineering Contradiction:

Improvedetection capabilityVSAvoiddetector durability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent implements an optical limiter positioned in front of the infrared detector that preemptively blocks sudden increases in infrared radiation intensity before they can damage the detector. This preliminary protective action allows the detector to maintain its detection capability for normal temperature variations while being protected from catastrophic damage due to sudden temperature spikes or bright infrared sources.

Inventive Principle:

Principle #9Preliminary anti-action

4Device complexity

If direct infrared to visible conversion is implemented, then device simplicity is improved, but human eye safety is compromised by sudden environmental temperature variations

Engineering Contradiction:

Improvesignal conversion systemVSAvoideye safety from temperature variations

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an electrical limiter as an intermediary between the infrared detector and the display system that mediates the conversion of infrared signals to visible display outputs. This electrical limiter prevents sudden environmental temperature variations from being directly translated into abrupt, potentially harmful changes in the displayed image, thereby protecting the user's eyes while maintaining the relative simplicity of the signal conversion system.

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

Enables the detection and display of room-temperature objects in complete darkness, providing a compact, user-friendly, and protective night vision solution suitable for both military and non-military applications, with the ability to distinguish non-fluorescent inks from substrates.

Implementation Method 1

employing an uncooled IR focal plane array (IRFPA)... operating in the 7 to 14 microns wavelength region

Methodology Applied

Scientific EffectInfrared radiation detection: Infrared Radiation

Implementation Method 2

Focusing is accomplished by adjusting the distance between a lens and the detector

Methodology Applied

Scientific EffectOptical focusing: Lens

Implementation Method 3

An optical limiter is used to protect the detector against sudden increases in object temperature

Methodology Applied

Scientific EffectOptical limiting: Filter (optical)

Data Source

PatentUS7459684B2Long-wavelength infra-red night vision goggles

Publication Date: 2008.12.02 LOCKHEED MARTIN CORP

AI summary

A night vision apparatus and method comprising employing a detector operating in the 7 to 14 microns wavelength region, converting via electronics and/or photonics the received light to the region visible to the human eye, and displaying the visible light on a display, wherein a housing contains the detector, the electronics and/or photonics, and the display.