Fabry-Perot Mirror Plate Elevated Sensor Electrodes

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Solution Overview

Problem

The accuracy of determining mirror spacing in Fabry-Perot interferometers is compromised by large electrode gaps, leading to low capacitance measurements and increased sensitivity to electromagnetic interference, which affects the precision of spectral peak positioning and spectral resolution.

Innovation Solution

The implementation of elevated sensor electrodes supported by a silica layer, which reduces the electrode gap and improves capacitance measurement accuracy by maintaining a stable and parallel support for the electrodes, while also serving as a protective mask during material deposition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If large electrode gaps are used in Fabry-Perot interferometers, then the device structure is simpler and easier to manufacture, but the capacitance measurement accuracy decreases and sensitivity to electromagnetic interference increases

Engineering Contradiction:
Improveease of manufactureVSAvoidcapacitance measurement accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent introduces a vertical elevation dimension by supporting the sensor electrode on a silica layer, transforming the electrode from a planar configuration to an elevated three-dimensional structure. This dimensional change reduces the electrode gap distance, thereby improving capacitance measurement accuracy without complicating the overall manufacturing process

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Device complexity

If large electrode gaps are used in Fabry-Perot interferometers, then the device structure is simpler, but the sensitivity to electromagnetic interference increases

Engineering Contradiction:
Improvedevice complexityVSAvoidsensitivity to electromagnetic interference
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

By elevating the sensor electrode vertically through silica layer support, the patent reduces the gap distance between electrodes. This dimensional modification decreases the antenna effect and electromagnetic interference sensitivity while adding minimal structural complexity to the device

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Measurement precision

If the electrode gap is reduced, then the capacitance measurement accuracy improves, but the electrode support structure becomes more complex

Engineering Contradiction:
Improvemirror spacing determination accuracyVSAvoidelectrode support structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces a silica layer as an intermediary material between the sensor electrode and the substrate. This intermediary structure serves multiple functions: providing mechanical support for the elevated electrode, reducing the electrode gap, and acting as a protective mask during material deposition, thereby achieving measurement precision improvement without excessive complexity

Inventive Principle:
Principle #24Intermediary (Mediator)

4Manufacturing precision

If elevated sensor electrodes are implemented, then spectral resolution improves through narrower transmission peaks, but the manufacturing process becomes more complex

Engineering Contradiction:
Improvespectral resolutionVSAvoidease of manufacture
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The silica layer supporting the elevated electrode serves multiple functions simultaneously: it provides mechanical support for electrode elevation, acts as a protective mask during material deposition processes, and enables the formation of narrow transmission peaks for improved spectral resolution. This multi-functionality achieves manufacturing precision improvement without proportionally increasing manufacturing complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

This approach enhances the accuracy of mirror spacing determination, leading to narrower transmission peaks and improved spectral resolution, while maintaining the interferometer's stability and resistance to electromagnetic interference.

Implementation Method 1

elevated sensor electrodes supported by a silica layer, which reduces the electrode gap and improves capacitance measurement accuracy by maintaining a stable and parallel support for the electrodes

Methodology Applied
Scientific EffectMechanical support:

Implementation Method 2

forming one or more capacitive sensor electrodes (90, 90a, 90b) by depositing conductive material on top of the intermediate layers (62)

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 3

A Fabry-Perot interferometer comprises a first semi-transparent mirror and a second semi-transparent mirror, which are arranged to form an optical cavity. The Fabry-Perot interferometer may provide one or more transmission peaks.

Methodology Applied
Scientific EffectInterference: Interference

Implementation Method 4

The interferometer may comprise e.g. a piezoelectric actuator for adjusting the mirror spacing. The piezoelectric actuator may be driven by applying a driving voltage to the actuator

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP2816389B1A method for producing a mirror for a Fabry-Perot interferomete
Publication Date: 2016.03.23 TEKNOLOGIAN TUTKIMUSKESKUS VTT OY
  • EP2816389B1 patent drawingFigure 1
  • EP2816389B1 patent drawingFigure 2a
  • EP2816389B1 patent drawingFigure 2b

AI summary

A method for producing a mirror plate (100) for a Fabry-Perot interferometer (700) may comprise: - providing a base slab (51), which comprises a substrate (50) coated with a reflective multilayer coating (60), - forming one or more intermediate layers (62) on the base slab (51) such that the lowermost intermediate layer (62) substantially consists of silica (SiO2), and such that the multilayer coating (60) is at least partially covered by the lowermost intermediate layer (62), - forming one or more capacitive sensor electrodes (90a, 90b) by depositing conductive material on top of the intermediate layers (62), and - removing material of the lowermost intermediate layer (62) by etching (ETCH1) in order to form an exposed aperture portion (AP1) of the multilayer coating (60).