Acoustic Backing Structure for Thin Space Charge Measurement

Solution Overview

Problem

Existing space charge measurement devices face challenges in accurately measuring space charge due to noise interference and increased weight and thickness caused by the use of copper backing materials, which require excessive thickness to prevent signal overlap.

Innovation Solution

A space charge measurement device incorporating a sound coupling unit, a sensor unit, a sound delay unit made of sound absorption materials like oak or glass-epoxy composite, and an amplification unit, with specific thickness and attenuation rate requirements to minimize noise and reduce weight and thickness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If copper backing material is used to prevent signal reflection and overlap, then measurement reliability is improved, but device weight and thickness increase excessively

Engineering Contradiction:

Improvemeasurement reliabilityVSAvoiddevice weight

Core Design Contradiction:

ReliabilityVSWeight of stationary object

Solution Approach 1:

The patent changes the key parameter from sound speed to sound attenuation coefficient by selecting foam material. This parameter substitution allows the backing layer to absorb acoustic energy rather than reflect it, eliminating the need for thick copper materials while maintaining measurement reliability and preventing signal overlap.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses a foam backing layer that is acoustically absorptive and can be replaced or adjusted easily. This approach replaces the permanent, heavy copper backing material with a lighter, consumable-like foam material that serves the same functional purpose of preventing signal reflection.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Reliability

If copper backing material is used to prevent signal reflection and overlap, then measurement reliability is improved, but device thickness increases excessively

Engineering Contradiction:

Improvemeasurement reliabilityVSAvoiddevice thickness

Core Design Contradiction:

ReliabilityVSLength of stationary object

Solution Approach 1:

The patent changes the key parameter from sound speed to sound attenuation coefficient by selecting foam material. This parameter substitution allows the backing layer to absorb acoustic energy rather than reflect it, eliminating the need for thick copper materials while maintaining measurement reliability and preventing signal overlap.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If sound coupling unit thickness is increased to accommodate thicker insulator samples, then adaptability is improved, but noise interference increases due to reflected signals

Engineering Contradiction:

Improveadaptability to different insulator thicknessesVSAvoidnoise interference

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful acoustic reflection at the backing layer interface into a beneficial signal absorption effect. By using foam material with appropriate acoustic impedance and high attenuation coefficient, the reflected noise is transformed into absorbed energy, eliminating interference while maintaining adaptability to different sample thicknesses.

Inventive Principle:

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

Solution Approach 2:

The patent changes the key parameter from sound speed to sound attenuation coefficient by selecting foam material. This parameter substitution allows the backing layer to absorb acoustic energy rather than reflect it, eliminating the need for thick copper materials while maintaining measurement reliability and preventing signal overlap.

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 device effectively minimizes noise interference and reduces weight and thickness by using polymer materials and sound absorption units, enabling accurate space charge measurement.

Implementation Method 1

A space charge measurement device converts a pressure wave, generated by a charge in an insulator in response to a high-voltage electric pulse applied from the outside, into an electrical signal through a piezoelectric sensor

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

a sound delay unit arranged to be adjacent to the sensor unit and made of a sound absorption material

Methodology Applied

Scientific EffectAcoustic absorption: Acoustic Absorption

Data Source

PatentEP4657087A1Lightweight and thin space charge measurement device

Publication Date: 2025.12.03 LS CABLE & SYST LTD

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AI summary

This space charge measurement device comprises: a sound coupling unit for sensing a sonic vibration generated from a cable to which an electric pulse is applied; a sensor unit for converting, into an electrical signal, the sonic vibration received from the sound coupling unit; a sound delay unit arranged to be adjacent to the sensor unit, and made of a sound absorption material; and an amplification unit for amplifying the electrical signal converted by the sensor unit.