Piezoelectric Actuator Auxiliary Electrode Charge Delay
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Solution Overview
Problem
The existing piezoelectric actuators face issues with delayed charge application to target electrode portions, leading to variations in activation characteristics and potential ink ejection failures, due to the asymmetrical capacitance distribution between individual electrodes and conductors, which can be exacerbated by the need to increase the size of the second common wiring to address this delay.
Innovation Solution
The introduction of auxiliary electrodes connected to the first connecting portions of the piezoelectric actuator, which overlap the first connecting portions and are spaced apart from the first conductor, allows for simultaneous charge application to target electrode portions without increasing the size of the actuator, thereby reducing or preventing delay in charge application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the area of the second common wiring is increased to reduce charge application delay, then the charge application timing is improved, but the size of the piezoelectric actuator increases
Solution Approach 1:
The invention divides the common wiring function into two separate conductors (first conductor and second conductor), each with dedicated wiring. This segmentation allows the first common wiring to be optimized for ground potential connection while the second common wiring handles driving potential, eliminating the need to increase the area of the second common wiring and thus avoiding actuator size increase while still reducing charge application delay
Solution Approach 2:
The first conductor acts as an intermediary element that provides a dedicated ground potential connection to the individual electrodes. By introducing this intermediate conductive layer between the individual electrodes and the ground, the patent creates a balanced capacitance distribution that reduces charge application delay without requiring enlargement of existing wiring structures
2Speed
If the distance between individual electrode and second conductor is reduced to increase capacitance, then the activation response is improved, but charge application delay increases due to insufficient second common wiring area
Solution Approach 1:
The patent segments the capacitance-forming structures into two balanced configurations: individual electrodes with first conductors, and individual electrodes with second conductors. This segmentation creates two separate capacitance pathways with comparable characteristics, ensuring that the increased capacitance from the second conductor does not create an imbalance that would delay charge application
Solution Approach 2:
The patent modifies the electrical parameters by providing dedicated wiring for both the first conductor (ground potential) and second conductor (driving potential). This parameter change in the wiring configuration balances the RC time constants of both capacitance pathways, optimizing both activation response speed and charge application timing
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 configuration ensures consistent and timely charge application to all target electrode portions, maintaining the actuator's activation characteristics without increasing the size of the piezoelectric actuator, thus preventing ink ejection failures and maintaining performance.
Implementation Method 1
a first piezoelectric layer and a second piezoelectric layer which are joined to each other
Data Source
AI summary
A piezoelectric actuator includes a first piezoelectric layer, a second piezoelectric layer, individual electrodes, a first conductor and an auxiliary electrode. The first piezoelectric layer and the second piezoelectric layer are joined to each other at a surface of the first piezoelectric layer. The individual electrodes are disposed on the first piezoelectric layer. The first conductor is spaced apart from the individual electrodes in a direction orthogonal to the surface of the first piezoelectric layer. The first conductor includes electrode portions and a connecting portion. The electrode portions each overlap a first portion of a corresponding one of the individual electrodes. The connecting portion connects at least two of the electrode portions to each other. The auxiliary electrode is connected to the connecting portion, overlaps the connecting portion, and is spaced apart from the first conductor in the direction.