Microsphere Reflector Homogeneous Calibration Thermal Imaging

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Solution Overview

Problem

Existing thermal imaging devices face challenges in achieving a homogeneous temperature distribution for calibration due to the large size and high manufacturing precision requirements of known reflectors, which result in non-uniform imaging properties among sensors.

Innovation Solution

A thermal imaging device with a reflector composed of microspheres, such as polymethylmetaacrylate or acrylic glass, that ensures diffuse reflection of thermal radiation, providing a low and homogeneous apparent temperature, and is arranged in a single layer or on a mirrored carrier film with gold vapor coating for optimal infrared radiation reflection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If cube-corner reflectors are used for calibration, then the intrinsic temperature of the detector can be reflected onto the detection area, but the reflectors are large, require high manufacturing precision and do not produce a particularly homogeneous temperature distribution

Engineering Contradiction:
Improvecalibration accuracyVSAvoidreflector size and manufacturing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The reflector is segmented into multiple microspheres of different sizes distributed across the calibration surface. This segmentation allows the reflector to achieve homogeneous temperature distribution through diffuse reflection while reducing the overall size and manufacturing complexity compared to traditional cube-corner reflectors.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the reflector use microspheres with different sizes and properties to create locally optimized reflection characteristics. The variation in microsphere dimensions ensures homogeneous apparent temperature across the entire detection area while maintaining a compact overall structure.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If traditional reflectors are used for calibration, then calibration can be performed, but they do not produce a homogeneous temperature distribution and require high manufacturing precision

Engineering Contradiction:
Improvemanufacturing precision requirementsVSAvoidtemperature distribution uniformity
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The reflector utilizes microspheres with varying diameters (parameter change) to achieve homogeneous temperature distribution. This parameter variation allows the system to produce uniform apparent temperature across the detection area while reducing manufacturing precision requirements compared to traditional reflectors.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If the reflector is made with microspheres of different diameters, then the reflection is particularly diffuse and the apparent temperature is particularly homogeneous, but the manufacturing complexity increases

Engineering Contradiction:
Improveapparent temperature homogeneityVSAvoidmicrosphere arrangement complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The reflector incorporates microspheres with different diameters in specific local regions to optimize diffusion characteristics. This local variation in microsphere size achieves homogeneous apparent temperature while keeping the overall manufacturing process manageable through systematic distribution patterns.

Inventive Principle:
Principle #3Local quality

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 microsphere reflector system allows for precise calibration by ensuring a uniform temperature distribution, reducing sensor variability and enabling effective correction of output signals, while being lightweight and mechanically stable, with adjustable reflection properties for varying temperature levels and wavelengths.

Implementation Method 1

a reflector (12) for reflecting the thermal radiation of the detector (8) onto the detection area of the detector (8)

Methodology Applied
Scientific EffectThermal radiation reflection: Reflection

Implementation Method 2

The microspheres ensure a particularly diffuse reflection of the thermal radiation with a low overall height

Methodology Applied
Scientific EffectDiffuse reflection: Scattering

Implementation Method 3

the microspheres are arranged on a carrier film and provided with a gold vapor coating. The gold vapor coating of the microspheres preferably causes a closed gold layer with a partially curved surface

Methodology Applied
Scientific EffectInfrared radiation reflection: Reflection

Implementation Method 4

A thermal imaging device (1) has a cooled infrared detector (8) with a large number of individual sensors

Methodology Applied
Scientific EffectInfrared detection: Photoelectric Effect

Data Source

PatentEP2000786B1Thermal imaging device with calibrating functionality
Publication Date: 2018.11.07 RHEINMETALL DEFENCE ELECTRONICS GMBH
  • EP2000786B1 patent drawingFigure 1
  • EP2000786B1 patent drawingFigure 2
  • EP2000786B1 patent drawingFigure 3~4

AI summary

The device (1) has a reflector (12) for reflecting thermal radiation of a cooled infrared detector (8) on a detection zone of the detector, where the reflector includes microspheres (3). The microspheres are arranged on a gold foil. The microspheres exhibit a diameter between 50 micrometers and 90 micrometers. A heating element e.g. Peltier element, is provided for heating the reflector. A distance of the reflector from the detector is variable. Two adjacent microspheres contact each other. The microspheres are formed of polymethylmethacrylate material.