Pseudo Continuous Wave Laser Illumination for Infrared Sensor Testing

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Solution Overview

Problem

Existing infrared illumination sources for missile detection sensors face limitations in generating high power in the mid-infrared wavelength range, leading to high input power requirements, thermal management issues, impractical operating conditions, limited beam width, modulation capabilities, and high electromagnetic emissions, which are inadequate for future sensor developments.

Innovation Solution

The use of a pseudo continuous wave laser infrared illumination source, such as an optical parametric oscillator or quantum cascade laser, which provides efficient in-band power output, reduces power requirements, minimizes eye safety issues, and allows for advanced modulation and beam shaping, enabling broader spectral tuning and higher pulse repetition frequencies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional infrared illumination sources (lamps or thin filaments) are used to illuminate missile detection sensors, then the sensors can be tested and evaluated, but the input power requirements become excessively high and thermal management issues arise

Engineering Contradiction:
Improvesensor testing capabilityVSAvoidinput power requirement
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent changes the fundamental operating parameters of the illumination source by using a pulsed laser system with specific pulse widths (10-1000 microseconds) and repetition frequencies (100 Hz - 10 kHz) matched to the sensor's integration time. This parameter optimization allows the system to deliver sufficient energy during the sensor's integration period while keeping average power consumption low, directly resolving the contradiction between reliable sensor testing and excessive power requirements

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention employs periodic pulsed illumination instead of continuous illumination. The laser emits short pulses synchronized with the sensor's integration cycles, providing all necessary energy in brief intervals. This periodic action maintains sensor testing reliability while dramatically reducing average power consumption and thermal load compared to continuous operation of traditional lamps

Inventive Principle:
Principle #19Periodic action

2Area of stationary object

If the beam width is increased to cover all infrared missile warning sensors on an aircraft, then complete sensor coverage is achieved, but the power density across the target decreases

Engineering Contradiction:
Improvesensor coverage areaVSAvoidpower density
Core Design Contradiction:
Area of stationary objectVSIllumination intensity

Solution Approach 1:

The patent uses dynamically controllable laser beam scanning or steering mechanisms that can concentrate energy on different sensor zones sequentially or simultaneously. The beam width and direction are dynamically adjusted to match the specific geometric arrangement of sensors on the aircraft, maintaining high power density while achieving complete coverage through temporal or spatial multiplexing

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The illumination system employs nested optical components including beam expanding optics, scanning mirrors, and focusing lenses that work together in a hierarchical manner. The laser beam is first expanded to cover the required angular range, then scanned across the sensor array, with optional intermediate focusing stages that maintain intensity distribution optimization throughout the nested optical train

Inventive Principle:
Principle #7Nested doll (Nesting)

3Adaptability or versatility

If traditional illumination sources are used, then the system can operate currently, but modulation capabilities are limited and cannot support future developed infrared missile detection sensors

Engineering Contradiction:
Improvefuture sensor compatibilityVSAvoidmodulation capability
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements a universal pulsed laser illumination platform that can be programmed with different pulse widths, repetition frequencies, and intensity patterns to match various sensor types and testing requirements. The system includes programmable control logic that can adapt to current and future sensor technologies, providing multi-functional capability that covers sensor testing, calibration, and evaluation across different generations of infrared missile detection systems

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The illumination system incorporates dynamically adjustable parameters including pulse width (10-1000 microseconds), repetition frequency (100 Hz - 10 kHz), and intensity modulation that can be programmed in real-time. This dynamic adaptability allows the same hardware platform to support both current sensor capabilities and future developments without requiring hardware changes, achieving universality through programmable control

Inventive Principle:
Principle #15Dynamics

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 solution offers higher in-band power efficiency, lower power consumption, improved eye safety, and enhanced modulation capabilities, enabling more effective testing and evaluation of infrared missile detection sensors with improved beam coverage and reduced electromagnetic compatibility issues.

Implementation Method 1

the pseudo continuous wave laser infrared illumination source is an optical parametric oscillator which is pumped by a laser

Methodology Applied
Scientific EffectOptical parametric oscillation:

Implementation Method 2

The modulation circuit comprises an acousto-optic modulator

Methodology Applied
Scientific EffectAcousto-optic effect: Acousto-optic Effect

Implementation Method 3

the pseudo continuous wave laser infrared illumination source is a quantum cascade laser

Methodology Applied
Scientific EffectQuantum cascade effect:

Data Source

PatentEP2013564B8Apparatus for use in operator training with, and the testing and evaluation of, infrared sensors which are for missile detection
Publication Date: 2016.07.27 TEXTRON SYSTEMS ELECTRONIC SYSTEMS UK LTD

AI summary

Apparatus (2) for use in operator training with, and the testing and evaluation of, missile detection systems which use infrared sensors which integrate incident energy over a finite time period, which apparatus (2) comprises at least one infrared illumination source (4) for illuminating the sensors, characterised in that the infrared illumination source (4) is a pseudo continuous wave laser infrared illumination source (4) with signal duty and peak power controlled by means of an amplitude, pulse width and pulse repetition interval modulation circuit (8), whereby the laser infrared illumination source (4) operates at shorter repetition intervals than the finite time period so that the laser infrared illumination source (4) appears to the infrared sensors to be a real missile signature.