Thermally Reflective Material for Thermal Imaging Identification
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Solution Overview
Problem
Existing identification systems using thermal infrared and near infrared imaging struggle to differentiate marked objects from unmarked ones, especially in ground-to-ground scenarios, due to lack of contrast and operational limitations of prior art systems, which are bulky, cumbersome, and unsuitable for personnel and portable equipment.
Innovation Solution
A method employing sheets of thermally reflective material with inclined facets that reflect thermal radiation from cold regions of the sky, providing directional reflection properties, allowing for unambiguous identification without needing to orient the material at specific angles, suitable for various surfaces including vertical and curved ones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional visible markings or retro-reflective materials are used for identification, then identification is possible in visible and near infrared wavelengths, but the markings have little or no contrast with the background at thermal infrared wavelengths and are not discernible through thermal imagers
Solution Approach 1:
The patent applies composite materials by combining multiple layers with different optical properties: a substrate layer, a dielectric mirror layer (comprising alternating high and low refractive index layers), and a metallic reflective layer. This composite structure enables the marking to reflect near-infrared light while maintaining high thermal infrared emissivity, achieving visibility in both near-infrared imaging systems and thermal imagers simultaneously.
Solution Approach 2:
The patent applies local quality by creating distinct optical properties in different layers of the marking structure. The dielectric mirror layer is designed with specific refractive index characteristics to reflect near-infrared wavelengths, while the metallic layer provides thermal infrared reflectivity. This localized functional differentiation allows the marking to exhibit wavelength-specific optical behaviors, enabling multi-wavelength identification capability.
2Illumination intensity
If thermal infrared reflective material is applied to create identification markings, then thermal infrared contrast is improved, but the material needs to be inclined at specific angles (0° to 40°) to function properly, limiting its application to air-to-ground scenarios
Solution Approach 1:
The patent applies phase transitions by utilizing the phase difference between near-infrared and thermal infrared wavelengths in the dielectric mirror layer. The alternating layers of different refractive indices create constructive interference for near-infrared reflection while allowing thermal infrared transmission. This wavelength-dependent phase manipulation enables the marking to provide contrast in both imaging modalities without requiring specific orientation angles.
Solution Approach 2:
The patent inverts the conventional approach by making the marking structure itself rather than relying on the inclination of the surface it's applied to. The dielectric mirror layer is designed with optical properties that actively manage wavelength-specific reflection and transmission, eliminating the need for angular positioning that characterizes prior art solutions.
3Illumination intensity
If prior art identification systems using inclined surfaces are used for ground-to-ground identification, then thermal infrared reflection from cold sky regions is achieved, but the systems are bulky, cumbersome, and unsuitable for personnel and portable equipment
Solution Approach 1:
The patent extracts the essential function of thermal infrared reflection from the bulky inclined surface structure of prior art systems. By applying a thin-film dielectric mirror coating directly to the marking surface, the system eliminates the need for large inclined frames or structures, retaining only the essential optical functionality while dramatically reducing weight and bulk for use on personnel and portable equipment.
Solution Approach 2:
The patent employs flexible shells and thin films by using a thin-film dielectric mirror coating that can be applied as a lightweight, flexible layer on marking surfaces. This thin-film approach replaces the rigid, bulky inclined structures of prior art with a flexible, lightweight coating that maintains thermal infrared reflective properties while being suitable for personnel gear and portable equipment.
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 provides a thin, adaptable, and efficient identification system that enhances contrast and visibility in thermal imagers, suitable for ground-to-ground identification, and is robust, lightweight, and easy to use on vehicles, structures, and personnel, with improved performance over prior art systems.
Implementation Method 1
a surface texture comprising a plurality of reflecting elements, wherein each element has a first facet which is substantially reflective at thermal infrared wavelengths and wherein the respective first facets form an angle 5° 40° with the plane of the sheet
Implementation Method 2
reflect thermal radiation from cold regions of the sky, providing directional reflection properties
Data Source
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AI summary
A sheet of thermally reflective material (1) has a surface texture comprising a plurality of reflecting elements (2), wherein each element has a first facet (4) which is substantially reflective at thermal infrared wavelengths and wherein the respective first facets (4) form an angle ? with the plane of the sheet (A-B) (0° < ? < 90°). Preferably, the first facets (4) are aligned such that, in use, thermal radiation is reflected from a common direction. By orienting the sheet of thermally reflective material to reflect cold regions of the sky, a marking material exhibiting a cold spot in a thermal imager can be provided.