Piezoelectric Actuator Electrode Segmentation for Droplet Accuracy
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Solution Overview
Problem
Existing piezoelectric actuators in inkjet heads face challenges in achieving precise control over liquid droplet discharge due to limitations in the design of the piezoelectric layer and electrode configuration, leading to inefficiencies in bending deformation and pressure application.
Innovation Solution
The proposed solution involves a piezoelectric actuator design with a layered structure comprising a piezoelectric layer, insulating layers, and conductor layers, where the U piezoelectric layer and DD conductor layer are used to regulate expansion and contraction, reducing unintended stress and increasing the intensity of electric fields, thereby enhancing the accuracy of liquid droplet discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional piezoelectric actuator design with simple electrode configuration is used, then the device complexity is low, but the manufacturing precision and control accuracy of liquid droplet discharge deteriorate
Solution Approach 1:
The piezoelectric actuator is divided into multiple functional layers including piezoelectric layers, insulating layers, and conductor layers. Each layer is segmented into specific regions (U regions and DD regions) that perform distinct functions, allowing precise control over bending deformation and electric field distribution to improve droplet discharge accuracy.
Solution Approach 2:
The patent introduces a multi-layered structure with conductor layers positioned at different heights (upper and lower sides) of the piezoelectric layers. This three-dimensional arrangement of electrodes creates controlled electric fields that regulate bending deformation more precisely, transforming a two-dimensional electrode problem into a three-dimensional solution.
2Manufacturing precision
If the piezoelectric layer expands and contracts without regulation, then the ease of operation is high, but the manufacturing precision and control over bending deformation deteriorate
Solution Approach 1:
Different regions of the piezoelectric actuator are given different properties through the insulating layers and conductor layer configuration. The U regions and DD regions have distinct electric field characteristics that regulate local bending deformation, allowing precise control over the overall bending shape while maintaining simple piezoelectric material properties.
Solution Approach 2:
Insulating layers are introduced as intermediary elements between the piezoelectric layers and conductor layers. These insulating layers mediate the electric field distribution, regulating how the piezoelectric layers expand and contract in response to applied voltages, thereby controlling bending deformation with improved precision.
3Manufacturing precision
If wiring lines extend from individual electrodes, then the ease of manufacture is high, but unintended stress and vibrations increase, deteriorating the manufacturing precision
Solution Approach 1:
The conductor layers are merged with the piezoelectric actuator structure itself, forming an integrated multi-layered device. The upper and lower conductor layers are positioned within the actuator body, eliminating the need for separate external wiring lines and reducing unintended stress and vibrations that would otherwise be introduced by external connections.
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 improves the accuracy and stability of liquid droplet discharge by reducing unnecessary vibrations and increasing the force applied to the multilayer body, resulting in more precise control over the discharge process.
Implementation Method 1
portions of the piezoelectric layer that are provided between the common electrode and the individual electrodes expand or contract in directions along the piezoelectric layer
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
A piezoelectric actuator includes a piezoelectric layer and a conductor layer that is provided directly or indirectly on the piezoelectric layer. In plan view, the conductor layer includes a plurality of individual electrodes that are arranged with intervals therebetween and a plurality of wiring lines that extend from the plurality of individual electrodes. Each wiring line includes a wide portion and a first narrow portion. The wide portion includes a part positioned at a center of the wiring line in a length direction. The first narrow portion is disposed between the wide portion and one of the plurality of individual electrodes to which the wiring line is connected. The first narrow portion has a width less than a width of the wide portion.