Nested Glass Interface Condensation Detection Using OCT

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Solution Overview

Problem

Current methods for detecting condensation on the inner surface of a lens in an interlocking device, such as a watch face, are either visually expensive in an industrial setting or highly dependent on lighting conditions, lacking automated control.

Innovation Solution

A method using optical coherence tomography (OCT) to measure interferometric signals after applying a thermal gradient to generate condensation on the inner surface of a glass, allowing precise detection of condensation through interferometric signal measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If visual detection methods (camera or naked-eye observation) are used to detect condensation, then the detection can be performed with simple equipment, but the detection is highly dependent on lighting conditions and cannot be automated for industrial production

Engineering Contradiction:

Improveautomated controlVSAvoiddetection reliability

Core Design Contradiction:

Extent of automationVSReliability

Solution Approach 1:

The patent replaces visual detection methods (optical/camera-based) with a thermal detection system. A temperature sensor directly measures the temperature of the lens inner surface, and condensation is detected by identifying temperature drops below a threshold. This substitution eliminates dependence on lighting conditions and enables automated industrial production while maintaining high detection reliability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces temperature as an intermediary parameter to detect condensation. Instead of directly observing condensation visually, the system measures temperature changes on the lens surface, which serve as an indirect but reliable indicator of condensation presence. This intermediary measurement enables automated detection independent of visual conditions.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Extent of automation

If camera-based detection is used, then automated control is possible, but the detection is highly dependent on lighting conditions and background characteristics

Engineering Contradiction:

Improveautomated controlVSAvoidlighting condition dependency

Core Design Contradiction:

Extent of automationVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the optical camera-based detection system with a thermal sensing system. Temperature sensors measure the lens surface temperature directly, eliminating all dependencies on lighting conditions, background characteristics, and optical path conditions. This substitution achieves both automated control and immunity to environmental optical factors.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Extent of automation

If pressure testing methods are used to check water resistance, then automated testing is possible, but the method does not directly detect condensation on the lens surface

Engineering Contradiction:

Improveautomated testingVSAvoidcondensation detection precision

Core Design Contradiction:

Extent of automationVSMeasurement precision

Solution Approach 1:

The patent replaces indirect pressure testing methods with direct thermal measurement on the lens surface. Temperature sensors placed in contact with or near the lens inner surface directly measure temperature changes caused by condensation, providing precise localization and detection of condensation on the specific surface of interest, rather than inferring water resistance from pressure test results.

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

Provides automated, lighting-independent detection of condensation with high sensitivity and accuracy, suitable for industrial production environments.

Implementation Method 1

apply a thermal gradient between the outer surface of the glass and the bottom for an initial period so as to obtain between the outer surface of the glass and the bottom a temperature difference ΔT s sufficient to generate condensation on at least a portion of an inner surface of the glass

Methodology Applied

Scientific EffectCondensation: Condensation

Implementation Method 2

provide an optical coherence tomography (OCT) device configured to measure an interferometric signal using a light beam

Methodology Applied

Scientific EffectInterference: Interference

Data Source

PatentEP4707958A1Method for characterizing physical interfaces of a nested device

Publication Date: 2026.03.11 ASSOC SUISSE POUR LA RECH HORLOGERE ASRH

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AI summary

This disclosure relates to a method for characterizing physical interfaces of a nested device (10) comprising a cavity (11) containing a volume of air and a glass (12), the cavity comprising walls (16) having a bottom (17) and a glass (12), provided with an inner surface (15) in contact with the volume of air and an outer surface (14) opposite the inner surface.The method comprises: applying a thermal gradient between the outer surface of the glass (12) and the bottom so as to obtain between the outer surface of the glass and the bottom a temperature difference ΔTs sufficient to generate condensation (25) on at least a portion (13) of the inner surface (15) of the glass (12); providing an optical coherence tomography (OCT) apparatus (30) configured to measure an interferometric signal; and once the temperature difference ΔTs has been obtained, measuring the interferometric signal for a measurement period (tm) so as to determine the presence of condensation on said at least a portion (13) of the inner surface (15) of the glass (12).