Infrared Safety Reflective Element for Thermal Contrast

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Solution Overview

Problem

Infrared thermographic cameras struggle to distinguish objects from their surroundings due to limited contrast in thermal radiation, especially in cases where objects have similar temperatures to their background, and existing safety reflective elements are ineffective in the infrared spectrum and require energy-consuming light sources.

Innovation Solution

An infrared security system incorporating an infrared thermographic camera and a safety reflective element with a functional optical surface that reflects sky radiation, providing enhanced contrast and visibility in the infrared spectrum without the need for light sources, using a movable or rotating mechanism to optimize visibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If infrared thermographic cameras are used to detect objects based on thermal radiation, then visibility of objects with different temperatures is improved, but objects with similar temperatures to their background become indistinguishable

Engineering Contradiction:
Improveobject detection capabilityVSAvoidcontrast information
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent introduces an intermediary substance (infrared-reflective coating or retroreflective element) that mediates between the object and the infrared thermographic camera. This intermediary reflects infrared radiation from the sky onto the object, creating an artificial thermal contrast that enables detection of objects with temperatures similar to their background, thus resolving the contradiction between detection capability and contrast information loss.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Illumination intensity

If visible light sources are used to illuminate surroundings, then visibility for human eyes is improved, but infrared thermographic cameras cannot distinguish objects from surroundings

Engineering Contradiction:
Improvevisible light illuminationVSAvoidinfrared detection capability
Core Design Contradiction:
Illumination intensityVSMeasurement precision

Solution Approach 1:

The patent applies local quality by using infrared-reflective materials specifically on the functional optical surface of safety reflective elements, while maintaining visibility for human eyes through the same surface. This localized application of infrared-reflective properties creates different optical characteristics for different wavelengths, enabling both human visibility and infrared detection without interference, thus resolving the contradiction between visible illumination and infrared detection capability.

Inventive Principle:
Principle #3Local quality

3Illumination intensity

If traditional retroreflective elements are used to reflect visible light, then visibility for drivers is improved, but they do not reflect infrared radiation

Engineering Contradiction:
Improvevisible light reflectionVSAvoidinfrared radiation reflection
Core Design Contradiction:
Illumination intensityVSMeasurement precision

Solution Approach 1:

The patent achieves universality by designing safety reflective elements that perform multiple functions: reflecting visible light for driver visibility and reflecting infrared radiation from the sky for infrared thermographic camera detection. The functional optical surface is engineered with infrared-reflective properties while maintaining retroreflective characteristics for visible light, thus resolving the contradiction between visible light reflection and infrared radiation reflection capabilities.

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

4Illumination intensity

If active safety lights are used to alert drivers, then visibility is improved, but energy consumption increases

Engineering Contradiction:
Improvesafety light visibilityVSAvoidenergy consumption
Core Design Contradiction:
Illumination intensityVSUse of energy by moving object

Solution Approach 1:

The patent applies self-service by using the sky as a free infrared light source that naturally illuminates the functional optical surface of the safety reflective element. This eliminates the need for energy-consuming active light sources, as the system harnesses ambient infrared radiation from the sky to provide visibility for infrared thermographic cameras, thus resolving the contradiction between visibility improvement and energy consumption.

Inventive Principle:
Principle #25Self-service

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 system significantly increases object visibility for infrared thermographic cameras across various weather conditions, enhancing safety in traffic scenarios by providing a wider contrast and reducing energy consumption, while maintaining compatibility with existing retroreflective elements.

Implementation Method 1

the functional optical surface of the safety reflective element is located in the field of view of the infrared thermographic camera, and the infrared thermographic camera is located in the field of reflection of the sky from the functional optical surface of the safety reflective element

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

The imaging of objects by an infrared thermographic camera is not affected by the aforementioned light problems

Methodology Applied
Scientific EffectThermal radiation: Thermal Radiation

Data Source

PatentEP4394735A1Infrared safety system to improve the visibility of objects and infrared safety reflective element
Publication Date: 2024.07.03 ZAPADOCESKA UNIVERZITA V PLZNI
  • EP4394735A1 patent drawingFigure 1
  • EP4394735A1 patent drawingFigure 2
  • EP4394735A1 patent drawingFigure 3

AI summary

The essence of the invention in that it contains an infrared thermographic camera and at least one safety reflective element, located on an object whose visibility is ensured, while the functional optical surface of the safety reflective element is located in the field of view of the infrared thermographic camera and the infrared thermographic camera is located in the field of reflection of the sky from the functional optical surface of the safety reflective element. The subject of the invention is also an infrared safety reflective element, the essence of which is that the functional optical surface of the safety reflective element has a spectral reflectance in the band 1 to 15 µm higher than 0.5, while the area of the functional optical surface is greater than 25 mm2.