Cantilever Electrode Capacitance Detection for Elastic Waves

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Solution Overview

Problem

Existing detecting devices face challenges in precisely detecting elastic waves due to air-induced attenuation between electrodes, leading to incomplete vibration detection.

Innovation Solution

A detecting device with a cantilever structure first electrode and a second electrode positioned closer to the fixed end, reducing air-induced attenuation by optimizing electrode placement and configuration for enhanced capacitance-based detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the second electrode extends to the position opposed to the free end of the first electrode, then the capacitance detection coverage is improved, but the air-induced attenuation of vibration increases

Engineering Contradiction:
Improvedetection precisionVSAvoidvibration attenuation
Core Design Contradiction:
Measurement precisionVSLoss of energy

Solution Approach 1:

The patent extracts the second electrode from the region opposite the free end of the first electrode. By removing the electrode portion that would cause excessive air attenuation, the vibration amplitude is preserved while maintaining sufficient capacitance detection capability through the remaining electrode configuration.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies local quality by creating non-uniform electrode distribution - the second electrode is positioned closer to the fixed end rather than extending to the free end region. This localized positioning optimizes the balance between detection capability and vibration preservation in different spatial zones.

Inventive Principle:
Principle #3Local quality

2Measurement precision

If the second electrode is positioned closer to the free end, then the vibration detection sensitivity is improved, but the air-induced attenuation increases

Engineering Contradiction:
Improvevibration detection sensitivityVSAvoidair attenuation effect
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful air attenuation effect into a beneficial design criterion by deliberately positioning the second electrode away from the free end region. This design choice uses the air attenuation characteristic to define the optimal electrode placement, transforming a negative physical effect into a guiding principle for device configuration.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Area of stationary object

If the electrode length is increased to improve detection coverage, then the detection area is expanded, but the vibration amplitude decreases due to air attenuation

Engineering Contradiction:
Improvedetection areaVSAvoidvibration amplitude
Core Design Contradiction:
Area of stationary objectVSStrength

Solution Approach 1:

The patent applies partial action by providing the second electrode with a length that is sufficient for effective capacitance detection but deliberately shorter than the full extent that would maximize detection area. This partial electrode configuration achieves the necessary detection coverage without excessive length that would cause harmful air attenuation and vibration amplitude reduction.

Inventive Principle:
Principle #16Partial or excessive action

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 device achieves precise detection of elastic waves by minimizing air-induced attenuation, allowing for accurate vibration measurement and target identification using the photoacoustic effect.

Implementation Method 1

a first electrode that is a plate having a cantilever structure with a fixed end FX and a free end FR and that vibrates by being bent by an elastic wave

Methodology Applied
Scientific EffectElastic wave: Sound

Implementation Method 2

the detecting device detects the elastic wave on the basis of a change in capacitance between the first electrode and the second electrode

Methodology Applied
Scientific EffectCapacitance change: Capacitance

Implementation Method 3

accurate vibration measurement and target identification using the photoacoustic effect

Methodology Applied
Scientific EffectPhotoacoustic effect: Photoacoustic Effect

Data Source

PatentEP3340652B1Detecting device
Publication Date: 2020.01.15 NIHON KOHDEN CORP
  • EP3340652B1 patent drawingFigure 1
  • EP3340652B1 patent drawingFigure 2
  • EP3340652B1 patent drawingFigure 3

AI summary

A detecting device 100 detects an elastic wave propagating through the air. The detecting device100 includes: a first electrode 12 that is a plate having a cantilever structure with a fixed end FX and a free end FR and that vibrates by being bent by the elastic wave; and a second electrode 32 that is a plate, that is opposed to the first electrode, and that has a predetermined distance from the first electrode. The detecting device 100 detects the elastic wave on the basis of a change in capacitance between the first electrode 12 and the second electrode 32. An end of the second electrode 32 in a direction from the fixed end FX to the free end FR is closer to the fixed end than the free end.