Deformable Membrane Fabry-Perot Sensor for Pressure and Temperature

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Solution Overview

Problem

Existing optical Fabry-Perot waveguide sensors face limitations in measuring pressure, force, and temperature due to rigid structures, limited measurement ranges, and the use of epoxy sealing, which complicates manufacturing and reduces sensitivity and adaptability.

Innovation Solution

A method for manufacturing an optical Fabry-Perot waveguide sensor with a deformable membrane at the end of the waveguide, using a capillary hollow core and a liquid drop, where the membrane is formed by solid-on-liquid deposition and coated with a reflecting layer, allowing for flexible deformation and improved sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a rigid taper plug with epoxy sealing is used to seal the fiber tip cavity, then the cavity can be sealed, but the measurement range is limited and the process becomes complicated and expensive

Engineering Contradiction:
Improvecavity sealingVSAvoidmanufacturing process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention removes the epoxy sealing layer and rigid taper plug from the system, replacing them with a deformable membrane sealed directly to the fiber tip cavity. This extraction of the problematic epoxy component eliminates the need for complex batch manufacturing processes while maintaining reliable sealing.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the mechanical parameter of the sealing structure from rigid (taper plug) to deformable (membrane). This parameter change allows the membrane to flex under pressure, expanding the measurement range while maintaining a simpler manufacturing process that doesn't require epoxy application.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a rigid taper plug is used to seal the fiber tip cavity, then the cavity is sealed, but the sensor cannot measure pressure as the tip is completely rigid

Engineering Contradiction:
Improvecavity sealingVSAvoidpressure measurement capability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The invention replaces the static rigid taper plug with a dynamic deformable membrane that can change shape in response to pressure variations. This dynamic structure allows the sensor to measure pressure by detecting membrane deformation while maintaining cavity sealing integrity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention employs a thin deformable membrane as the sealing structure instead of a rigid taper plug. This flexible film can deflect under pressure, enabling pressure measurement capability while still providing reliable cavity sealing.

Inventive Principle:
Principle #30Flexible shells and thin films

3Reliability

If epoxy is used to seal the fiber tip cavity, then the cavity is sealed, but the epoxy-taper plug cannot withstand temperatures higher than 39°C

Engineering Contradiction:
Improvecavity sealingVSAvoidmaximum operating temperature
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The invention extracts the epoxy material from the sealing structure, eliminating the temperature limitation imposed by epoxy's maximum operating temperature of 39°C. The deformable membrane provides sealing without this thermal constraint, enabling high-temperature operation.

Inventive Principle:
Principle #2Taking out (Extraction)

4Measurement precision

If a deformable membrane is used at the waveguide end, then sensitivity and adaptability are improved, but the manufacturing process becomes more complex

Engineering Contradiction:
Improvesensor sensitivityVSAvoidmanufacturing process complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The invention merges the sealing function and the sensing function into a single deformable membrane structure. This integration eliminates the need for separate epoxy sealing and rigid plug components, simplifying the manufacturing process while maintaining high sensitivity and adaptability for multiple measurement types.

Inventive Principle:
Principle #5Merging (Combining)

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 sensor can accurately measure pressure, force, and temperature with enhanced sensitivity and adaptability, overcoming the limitations of prior art by using a deformable membrane that can withstand varying conditions without epoxy sealing, enabling broader measurement ranges and improved reliability.

Implementation Method 1

adhering a liquid drop to said exit so as to form a convex surface

Methodology Applied
Scientific EffectSurface tension: Surface Tension

Implementation Method 2

adhering a liquid drop to said exit

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 3

depositing the deformable membrane by a solid-on-liquid deposition technique on said convex surface

Methodology Applied
Scientific EffectSolid-on-liquid deposition: Deposition (physical)

Implementation Method 4

depositing a reflecting layer on said deformable membrane

Methodology Applied
Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Implementation Method 5

optical measurement systems based on Fabry-Perot waveguide tip sensors

Methodology Applied
Scientific EffectFabry-Perot interference: Fabry-Perot Interferometer

Implementation Method 6

The optical signal from the lead optical fiber is split into two paths, which mutually interfere

Methodology Applied
Scientific EffectLight interference: Interference

Implementation Method 7

deformable membrane that can withstand varying conditions

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3163340B1Method of fabrication of an optical waveguide sensor and such optical waveguide sensor
Publication Date: 2023.10.11 HAUTE ECOLE ARC
  • EP3163340B1 patent drawingFigure 1~2
  • EP3163340B1 patent drawingFigure 3~5
  • EP3163340B1 patent drawingFigure 6

AI summary

In the present invention, methods to manufacture and devices are disclosed for implementing Fabry-Perot optical waveguide sensors in different configurations. The configurations comprise a deformable membrane (30) fixed to an optical cavity (20) that is adapted to an optical waveguide. The optical cavity comprises at least a longitudinally traversing hollow core connected to the entry and the exit of the optical cavity and comprises a volume of air (50) situated to the side of the entry and a volume of liquid (40) situated to the side of the deformable membrane. The volume of liquid is in contact with the deformable membrane and with the exit of the optical cavity and the volume of air is in fluidic connection, by the volume of liquid, with said deformable membrane.