Piezoelectric Element Electrode Connection Reliability

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Solution Overview

Problem

Existing piezoelectric elements with hole-based protective layers are prone to electrode layer breakage due to external forces, leading to poor connections and oxidation issues when conductive materials are inserted for electrical contact.

Innovation Solution

A piezoelectric element design featuring a conductive foil with a filling member and covering member, where the filling member is electrically connected to the electrode layer through the conductive foil and the covering member has a through-hole for a conductive member connection, preventing electrode layer breakage and oxidation by covering the filling member and providing a reliable electrical connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a hole is provided in the protective layer to insert conductive material for electrical connection, then electrical connection can be secured, but the electrode layer becomes easily broken by external forces

Engineering Contradiction:
Improveelectrical connectionVSAvoidelectrode layer
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent applies beforehand cushioning by providing a reinforcing layer between the protective layer and the electrode layer at the hole position. This reinforcing layer is prepared in advance to cushion and distribute external forces before they reach the electrode layer, preventing breakage while maintaining the electrical connection function through the hole.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent uses an intermediary approach by introducing a reinforcing layer as a mediator between the protective layer and the electrode layer. This intermediate layer transfers and distributes mechanical stresses, preventing direct force transmission to the fragile electrode layer while allowing the conductive material to pass through the hole for electrical connection.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Length of moving object

If the electrode layer is made extraordinarily thin to enable voltage application and vibration, then the piezoelectric element achieves flexibility and thinness, but the electrode layer becomes difficult to draw out and prone to oxidation

Engineering Contradiction:
ImprovethicknessVSAvoidelectrode layer handling
Core Design Contradiction:
Length of moving objectVSEase of operation

Solution Approach 1:

The patent applies segmentation by separating the electrode layer into two functional parts: the thin piezoelectric electrode layer for voltage application and vibration, and the separate conductive material in the hole for electrical connection and wire attachment. This segmentation allows the piezoelectric electrode layer to remain extremely thin while the conductive material handles the mechanical operations of drawing and connection.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses an intermediary approach by introducing conductive material as a mediator between the thin piezoelectric electrode layer and the external wire connection. This intermediate conductive material enables electrical connection without requiring the piezoelectric electrode layer itself to be drawn out, thus preventing oxidation and handling difficulties.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If conductive material is inserted into the hole for electrical connection, then electrical contact is established, but external forces cause peeling between conductive material and electrode layer leading to poor connection

Engineering Contradiction:
Improveelectrical connectionVSAvoidconnection stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies beforehand cushioning by placing the reinforcing layer between the protective layer and the electrode layer at the hole position. This reinforcing layer cushions external forces before they cause peeling between the conductive material and electrode layer, ensuring stable electrical connection by distributing mechanical stresses away from the connection interface.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent uses an intermediary approach by introducing the reinforcing layer as a mediator that stabilizes the connection between the conductive material and electrode layer. This intermediate layer prevents direct peeling forces from separating the conductive material from the electrode layer, ensuring reliable electrical connection under external forces.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 design enhances the reliability of electrical connections and prevents electrode layer breakage and oxidation, ensuring stable operation of the piezoelectric element under external forces.

Implementation Method 1

a piezoelectric element including a piezoelectric layer, electrode layers formed on both sides of the piezoelectric layer

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP4061008B1Piezoelectric element
Publication Date: 2024.03.27 FUJIFILM CORP
  • EP4061008B1 patent drawingFigure 1~2
  • EP4061008B1 patent drawingFigure 3~4
  • EP4061008B1 patent drawingFigure 5~7

AI summary

Provided is a piezoelectric element capable of preventing the occurrence of poor connection to an electrode layer. A piezoelectric element includes a piezoelectric layer, electrode layers formed on both sides of the piezoelectric layer, and a protective layer laminated on a surface of the electrode layer opposite to a surface on a piezoelectric layer side, in which the piezoelectric element includes a conductive foil laminated on a surface of the protective layer opposite to the electrode layer, the protective layer has a hole that penetrates from a surface to the electrode layer, the conductive foil includes an opening portion at a position that overlaps with the hole of the protective layer in a surface direction, the piezoelectric element includes a filling member consisting of a conductive material, which is formed on at least a part of a surface of the conductive foil from insides of the hole of the protective layer and an opening portion of the conductive foil and is electrically connected to the electrode layer and the conductive foil, and a covering member that covers the filling member and the conductive foil, the covering member has a through-hole at a position that does not overlap with the filling member in the surface direction, and the piezoelectric element includes a conductive member, which is inserted into the through-hole of the covering member and electrically connected to the conductive foil.