Transparent Ceramic Dewar Watch Insulation

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Solution Overview

Problem

Conventional watches, especially electronic ones, are unable to function properly in extreme temperature environments, such as those encountered in space or lunar missions, where temperatures can range from -150 °C to +125 °C.

Innovation Solution

A Dewar device with a transparent ceramic dressing element, such as ice cream, is used to provide thermal insulation for the mechanical and functional components of a watch. This device includes a bracelet and a case with an enclosure that houses the watch box, along with a fixing device to maintain the watch box away from the enclosure elements. The transparent dressing element is made from materials like aluminum oxynitride, alumina-magnesia, yttrium oxide, or yttrium and aluminum garnet, offering high hardness, light transmission, and resistance to radiation and chemicals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional transparent materials (glass, quartz) are used for the covering element, then ease of manufacture is improved, but thermal insulation performance deteriorates because they cannot withstand extreme temperatures

Engineering Contradiction:
Improveease of manufactureVSAvoidthermal insulation performance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent employs transparent ceramic materials (such as aluminum oxynitride, alumina-magnesia, yttrium oxide, or yttrium aluminum garnet) that combine the transparency of glass with the extreme temperature resistance of ceramics. These composite materials maintain optical clarity while providing the thermal stability required for space and lunar missions, resolving the contradiction between ease of manufacture and thermal insulation performance.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention changes the material parameters by transitioning from conventional glass/quartz to advanced transparent ceramics with specific compositional parameters (aluminum oxynitride, alumina-magnesia, yttrium oxide, yttrium aluminum garnet). This parameter change enables the material to withstand temperatures from -150°C to +125°C while maintaining transparency, thus improving thermal insulation performance without sacrificing manufacturability.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If the watch case is placed directly in the enclosure without fixation devices, then device complexity is reduced, but the watch case may contact enclosure elements causing thermal conduction and temperature instability

Engineering Contradiction:
Improvedevice complexityVSAvoidtemperature stability
Core Design Contradiction:
Device complexityVSTemperature

Solution Approach 1:

The patent introduces fixing devices as intermediary elements between the watch case and the enclosure. These devices serve as thermal isolators that prevent direct contact between the watch case and the enclosure walls, thereby blocking thermal conduction pathways. This intermediary structure maintains temperature stability while adding minimal complexity to the overall device.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If transparent ceramic material is used for the covering element, then thermal insulation performance is improved, but manufacturing complexity increases due to sintering process requirements

Engineering Contradiction:
Improvethermal insulation performanceVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent specifies precise compositional parameters for the transparent ceramic materials (aluminum oxynitride, alumina-magnesia, yttrium oxide, yttrium aluminum garnet) that enable them to achieve optimal thermal insulation properties. By controlling these material parameters and using standardized sintering processes, the manufacturing complexity is managed while maintaining superior thermal insulation performance.

Inventive Principle:
Principle #35Parameter changes

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 Dewar device effectively maintains a stable temperature within the watch box, preventing thermal loss and ensuring the watch's components remain operational for extended periods, even in extreme external temperature conditions.

Implementation Method 1

The transparent covering element (10a) helps to protect the case (6) of the watch (3)... providing in particular good thermal insulation to mechanical and/or functional components (2)

Methodology Applied
Scientific EffectThermal radiation blocking: Thermal Radiation

Implementation Method 2

a fixing device (7) fixing the watch case (6) in the enclosure (5) of the case (4) while keeping it away from all the elements (10a to 10c) of the case (4) defining this enclosure (5)

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP4120029B1Dewar device comprising a transparent trim element
Publication Date: 2025.04.30 OMEGA SA
  • EP4120029B1 patent drawingFigure 1

AI summary

One aspect of the invention relates to a Dewar device (1) for mechanical and/or functional components (2) of a watch (3), said device (1) being provided with a strap and a case (4) comprising a compartment (5) in which a case (6) of said watch (3) can be arranged and at least one fixing device (7) fixing said case (6) of watch (3) in said compartment (5) of the case (4) keeping it away from all the elements (10a, 10b, 10c) of the case (4) defining this compartment (5), said assembly (10a, 10b, 10c) comprising at least one transparent covering element (10a) of transparent ceramic material in particular of transparent polycrystalline ceramic material.