Multi-Spectral Alignment Assembly Using Reflective and Thermal Plates

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Solution Overview

Problem

Conventional multi-spectral electro-optical systems face challenges in maintaining alignment across various spectral bands due to the limitations of targeting boards, which are often inconsistent, unreliable, and difficult to illuminate uniformly across multiple spectral bands, especially in the infrared spectrum.

Innovation Solution

An alignment assembly comprising a reflective front plate with apertures and a thermally-responsive backplate, illuminated by a source emitting in one spectral band and heated to emit thermal radiation in another, allowing imaging sensors to align across a wide spectral range by creating image contrasts in both visible and infrared bands.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional targeting boards are used for alignment, then alignment can be detected and cured during initial alignment and periodic realignment, but the targeting boards are inconsistent, unreliable, and difficult to illuminate uniformly across multiple spectral bands especially in the infrared spectrum

Engineering Contradiction:
Improvealignment reliabilityVSAvoidspectral band adaptability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The alignment assembly merges multiple functional elements into a single integrated unit: a front plate with aperture patterns for visible light alignment, a back plate with thermal emissivity patterns for infrared alignment, and illumination/thermal sources. This combination allows simultaneous multi-spectral alignment in one device, eliminating the need for separate targeting boards for different spectral bands and improving both reliability and spectral adaptability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The alignment assembly is designed as a universal device that performs multiple alignment functions across different spectral bands. The front plate apertures work with visible light illumination for optical alignment, while the back plate thermal patterns work with infrared radiation for thermal alignment. This multi-functional design allows a single assembly to serve all imaging sensors across the entire spectral range, replacing multiple specialized targeting boards.

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

2Measurement precision

If separate targeting boards are used for different spectral bands, then each spectral band can be aligned, but the system complexity increases and alignment consistency across bands becomes difficult to maintain

Engineering Contradiction:
Improvealignment precisionVSAvoidalignment system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines separate alignment functions for different spectral bands into a single integrated alignment assembly. The front plate with apertures and the back plate with thermal patterns are merged into one unit that can be positioned simultaneously in front of multiple imaging sensors. This consolidation maintains high alignment precision for each spectral band while reducing overall system complexity by eliminating the need for multiple separate targeting boards and their respective alignment procedures.

Inventive Principle:
Principle #5Merging (Combining)

3Adaptability or versatility

If thermal radiation is used for infrared alignment, then infrared imaging sensors can align, but the illumination source must also provide visible light for other sensors

Engineering Contradiction:
Improvespectral coverageVSAvoidillumination energy requirement
Core Design Contradiction:
Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The alignment assembly merges visible light illumination and thermal radiation generation into a single integrated device. The illumination source provides visible light for optical alignment of visible sensors, while the thermal source generates infrared radiation for alignment of thermal sensors. Both energy types are generated within the same assembly structure, allowing simultaneous multi-spectral alignment without requiring separate illumination systems for each spectral band.

Inventive Principle:
Principle #5Merging (Combining)

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 enables precise and reliable alignment of multi-spectral imaging sensors across multiple spectral bands, improving alignment accuracy and reducing maintenance overhead, while being compact and inexpensive compared to existing methods.

Implementation Method 1

a first plate having a plurality of apertures formed in a reflective surface thereof, the reflective surface of the first plate being disposed to reflect the illumination emitted by the illumination source

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

a heating element coupled to the second plate and configured to heat the second plate to emit thermal infrared radiation

Methodology Applied
Scientific EffectJoule Heating: Joule Heating

Implementation Method 3

heat the second plate to emit thermal infrared radiation from the second plate, in a second spectral band

Methodology Applied
Scientific EffectThermal Radiation: Thermal Radiation

Data Source

PatentEP3669139B1Alignment assembly and method for multi-spectral optical systems
Publication Date: 2022.10.05 RAYTHEON CO
  • EP3669139B1 patent drawingFigure 1
  • EP3669139B1 patent drawingFigure 2
  • EP3669139B1 patent drawingFigure 3

AI summary

Aspects are generally directed to an alignment assembly and method for aligning a multispectral optical system. The alignment assembly includes an illumination source (110) configured to emit illumination in a first spectral band, and a first plate (105) having a plurality of apertures formed in a reflective surface thereof. The reflective surface of the first plate is disposed to reflect the illumination emitted by the illumination source. The alignment assembly also includes a second plate (115) positioned proximate to the first plate and spaced apart from the first plate to define a gap (121) between the first plate and the second plate, the first plate being interposed between the second plate and the illumination source, and a heating element (120) coupled to the second plate and configured to heat the second plate to emit thermal infrared radiation, from the second plate, in a second spectral band.