Piezoelectric Actuator Barrier Layer Suppresses Atom Diffusion
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Solution Overview
Problem
Existing piezoelectric actuators for ink-jet heads face deterioration in piezoelectric characteristics due to diffusion of constitutive atoms from the vibration plate into the piezoelectric layer, leading to reduced deformation and performance.
Innovation Solution
A method involving the formation of a through-hole in the base member before annealing the piezoelectric layer, which prevents diffusion of constitutive atoms into the active portion of the piezoelectric layer, combined with the use of an aerosol deposition method for forming densified vibration and piezoelectric layers, and controlled sintering of electrodes to maintain the piezoelectric characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the vibration plate is joined to the channel unit and a lower electrode is formed as a diffusion-preventive layer, then the diffusion of constitutive atoms is partially suppressed, but the piezoelectric characteristic still deteriorates due to insufficient blocking of atom diffusion
Solution Approach 1:
A barrier layer is introduced as an intermediary between the vibration plate and the piezoelectric layer. This barrier layer serves as a more effective diffusion-preventive layer that successfully blocks constitutive atoms from the vibration plate from diffusing into the piezoelectric layer, thereby preventing deterioration of piezoelectric characteristics while maintaining the structural integrity of the actuator.
Solution Approach 2:
The barrier layer is formed in advance before the piezoelectric layer is deposited. This preliminary action ensures that the diffusion-preventive function is already in place before any potential contamination can occur during subsequent processing steps, proactively preventing the harmful diffusion effect.
2Reliability
If the piezoelectric layer is annealed at high temperature to achieve piezoelectric characteristics, then the piezoelectric property is improved, but constitutive atoms from the vibration plate diffuse into the piezoelectric layer causing deterioration
Solution Approach 1:
The barrier layer acts as a thermal and diffusion barrier during the annealing process. It allows the piezoelectric layer to be heated to the required temperature for developing piezoelectric characteristics while preventing the constitutive atoms from the vibration plate from diffusing into the piezoelectric layer, thus decoupling the beneficial thermal effect from the harmful diffusion effect.
3Object-affected harmful factors
If a diffusion-preventive layer is placed between the piezoelectric layer and vibration plate, then atom diffusion is reduced, but the lower electrode cannot sufficiently stop diffusion into the active portion of the piezoelectric layer
Solution Approach 1:
The barrier layer is strategically positioned and designed to provide sufficient diffusion prevention while maintaining the deformation characteristics of the active portion. It creates an effective diffusion barrier without interfering with the mechanical deformation required for actuator operation, thus resolving the contradiction between diffusion prevention and manufacturing precision.
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 effectively suppresses the deterioration of piezoelectric characteristics, allowing for enhanced deformation and performance of the piezoelectric actuator, enabling high integration and efficient ink discharge.
Implementation Method 1
a piezoelectric layer, which is composed of a piezoelectric material
Implementation Method 2
a vibration layer and a piezoelectric layer which are composed of a ceramics material and formed by means of the aerosol deposition method (AD method)
Implementation Method 3
the annealing, in which the piezoelectric layer is heated at a high temperature, is performed in order that the piezoelectric layer, which is formed by the AD method, has the piezoelectric characteristic
Implementation Method 4
constitutive atoms of the vibration plate, which are heated together with the piezoelectric layer, are diffused
Data Source
AI summary
A method for producing a liquid transport apparatus is disclosed. The liquid transport apparatus includes a pressure chamber plate, a ceramics layer formed on a surface of the pressure chamber plate, a piezoelectric layer formed on the ceramics layer, and an electrode formed on the piezoelectric layer. The ceramics layer is formed by heating an insulating ceramic material at a temperature lower than an annealing temperature of the piezoelectric layer. Accordingly, the atoms of the pressure chamber plate are suppressed from being diffused into the piezoelectric layer.