Piezoelectric Actuator Electrode Alignment via Through-Holes

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Solution Overview

Problem

The piezoelectric actuator in existing inkjet devices is prone to misregistration of the penetrating conductor and surface electrode due to variations in the piezoelectric ceramic layer, leading to electrical connection issues, which can be mitigated by increasing the size of the surface electrode, but this increases the size of the actuator.

Innovation Solution

A piezoelectric actuator design featuring a ceramic substrate with a vibrating plate, a common electrode, and a piezoelectric ceramic layer with first through holes and individual electrodes, where the first surface electrodes are long and arranged along the central part of the ceramic substrate, allowing for improved electrical connection without increasing the actuator's size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the size of the surface electrode is increased to cope with misregistration, then the electrical connection reliability is improved, but the size of the piezoelectric actuator is increased

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidactuator size
Core Design Contradiction:
ReliabilityVSArea of moving object

Solution Approach 1:

The invention transitions from a two-dimensional surface electrode layout to a three-dimensional configuration by placing electrodes inside through-holes that penetrate the piezoelectric ceramic layer. This vertical dimensionality change allows electrical connection without increasing the horizontal footprint of the actuator, resolving the contradiction between connection reliability and compact size.

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

Solution Approach 2:

The surface electrode is nested within the through-hole structure, with the electrode material contained inside the hollow cylindrical space formed by the through-hole. This nesting approach allows the electrical connection path to be embedded within the existing ceramic structure rather than adding external extensions, maintaining compact dimensions while ensuring reliable electrical connection.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Manufacturing precision

If the penetrating conductor and surface electrode alignment is improved, then the manufacturing precision is improved, but the device complexity increases

Engineering Contradiction:
Improveelectrode alignment precisionVSAvoidstructure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The through-hole structure serves multiple functions simultaneously: it provides the electrical conduction path, defines the surface electrode position, and acts as an alignment reference feature. This multi-functionality eliminates the need for separate alignment mechanisms, reducing overall device complexity while improving manufacturing precision.

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

Solution Approach 2:

The through-holes are formed in the piezoelectric ceramic layer before the surface electrodes are applied. This preliminary action establishes fixed reference positions that guide subsequent electrode placement, ensuring precise alignment without requiring complex real-time adjustment mechanisms during manufacturing.

Inventive Principle:
Principle #10Preliminary 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

This design enhances the electrical connection between the common and surface electrodes through the piezoelectric ceramic layer without enlarging the actuator, maintaining printing accuracy and resolution.

Implementation Method 1

a piezoelectric ceramic layer held between the common electrode and the individual electrode

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP2738001B1Piezoelectric actuator, liquid discharge head, and recording device
Publication Date: 2016.09.07 KYOCERA CORP
  • EP2738001B1 patent drawingFigure 1
  • EP2738001B1 patent drawingFigure 2
  • EP2738001B1 patent drawingFigure 3

AI summary

Provided are a piezoelectric actuator that achieves a satisfactory electrical connection of a common electrode and a surface electrode without increasing the size of the piezoelectric actuator, as well as a liquid discharge head and a recording device. The piezoelectric actuator includes: a ceramic substrate which is long in one direction and includes a vibrating plate 21a, a common electrode 24 disposed on the vibrating plate 21a, and a piezoelectric ceramic layer 21b disposed on the common electrode 24 and having a plurality of first through holes 29a connected to the common electrode 24; a plurality of individual electrodes 25 disposed in a region of the piezoelectric ceramic layer 21b opposed to the common electrode 24; and a plurality of first surface electrodes 21a respectively disposed inside a plurality of the first through holes 29a in the piezoelectric ceramic layer 21b and on a circumference of a plurality of the first through holes 29a. A plurality of the first through holes 29a are arranged along the one direction at a central part of the ceramic substrate in a direction orthogonal to the one direction. The first surface electrodes 28a are long in the one direction.