Floating Optical Mount for Infrared Sensor Thermal Stability

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Solution Overview

Problem

Non-contact temperature measuring devices, particularly infrared pyrometers, face challenges due to components being sensitive to temperature changes, leading to inaccurate measurements caused by different thermal expansion coefficients, which affect the optical element's position and measuring range over time.

Innovation Solution

A hand-held infrared measuring device with a floating mount for the optical element, using an elastic bearing to compensate for thermal expansion and maintain a defined position, coupled with a metal tube for thermal stabilization and a ventilation channel for pressure equalization, ensuring accurate temperature measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the optical element is rigidly mounted in the device housing, then the structural stability is improved, but measurement accuracy deteriorates due to thermal expansion differences causing position shifts

Engineering Contradiction:
Improvestructural stabilityVSAvoidmeasurement accuracy
Core Design Contradiction:
Stability of the object's compositionVSMeasurement precision

Solution Approach 1:

The optical element is mounted in a floating manner on an elastic bearing, allowing it to move dynamically in response to thermal expansion while maintaining optical alignment. The elastic bearing enables the optical element to adjust its position as temperature changes, preventing measurement errors caused by rigid mounting constraints.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The elastic bearing is specifically designed to compensate for thermal expansion differences between the optical element and device housing. As temperature changes cause different expansion rates, the elastic bearing absorbs these dimensional changes, maintaining the optical element's functional position relative to the sensor.

Inventive Principle:
Principle #37Thermal expansion

2Measurement precision

If the optical element is mounted with play to accommodate thermal expansion, then measurement accuracy is improved, but device complexity increases due to additional mounting mechanisms

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidmounting mechanism complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The elastic bearing acts as a flexible mounting element that provides the necessary play for thermal expansion compensation without requiring complex mechanical adjustment mechanisms. This flexible mounting solution simplifies the overall device structure while achieving the required measurement accuracy.

Inventive Principle:
Principle #30Flexible shells and thin films

3Ease of manufacture

If conventional adhesives are used to mount the optical element, then manufacturing simplicity is improved, but measurement accuracy deteriorates due to adhesion failure and outgassing

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidmeasurement accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent replaces adhesive bonding with a mechanical floating mounting system using an elastic bearing. This mechanical solution eliminates the adhesion and outgassing problems inherent in conventional adhesive mounting, while maintaining manufacturing feasibility through standardized elastic bearing components.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 effectively minimizes internal tension and maintains the optical element's position, providing accurate and stable temperature measurements by compensating for thermal expansion and ensuring thermal equilibrium, thus improving measurement accuracy and reducing deformation effects.

Implementation Method 1

the different thermal expansion coefficients of the optical element and its mount, for example a lens and corresponding lens mount, can be taken into account on the one hand by compensating for example with an elastic element

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

detect the thermal radiation emitted by an object, whose intensity and position of the emission maximum depend on its temperature

Methodology Applied
Scientific EffectInfrared radiation: Infrared Radiation

Implementation Method 3

detect the thermal radiation emitted by an object

Methodology Applied
Scientific EffectThermal radiation: Thermal Radiation

Implementation Method 4

a ventilation channel for pressure equalization, ensuring accurate temperature measurement

Methodology Applied
Scientific EffectPressure equalization:

Data Source

PatentEP2706331B1Temperature measuring apparatus, in particular hand-held infrared measurement device
Publication Date: 2017.09.06 ROBERT BOSCH GMBH
  • EP2706331B1 patent drawingFigure 1
  • EP2706331B1 patent drawingFigure 2
  • EP2706331B1 patent drawingFigure 3

AI summary

The device (10) has an infrared sensor that is configured for non-contact temperature measurement arranged in housing (12). A floatingly mounted optical element configured for focusing the outgoing of infrared radiation from the object to the infrared sensor. The optical element of infrared radiation (IR)-housing is pressed against a tube. An adhesive layer is provided on the optical element facing side of an elastic element. The elastic element is formed on the optical element.