Piezoelectric Actuator Inversion for Inkjet Head Control
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Solution Overview
Problem
Existing piezoelectric actuators in inkjet heads face challenges with compact size, directional displacement control, and high costs due to orientation-dependent film thickness and electrical cross-talk issues, leading to inefficient ink ejection and increased power consumption.
Innovation Solution
A method of driving a piezoelectric actuator with a diaphragm, a lower electrode, and a piezoelectric film oriented in the (111) direction, where the electric field is applied opposite to the polarization direction, allowing for controlled displacement and avoiding electrical cross-talk by using a positive voltage drive signal, thus reducing costs and improving ejection efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a piezoelectric film is manufactured by sputtering with orientation, then the film thickness can be reduced to achieve compact size, but the displacement amount varies depending on the electric field direction
Solution Approach 1:
The patent inverts the conventional electrode configuration by making the lower electrode the address electrode and the upper electrode the ground electrode. This reversal allows the electric field to be applied in the direction that produces maximum displacement in oriented piezoelectric films deposited by sputtering, thereby achieving both compact size and precise displacement control
2Ease of manufacture
If a positive electric field is applied to the upper electrode, then the driving circuit cost is reduced, but electrical cross-talk occurs between adjacent electrodes
Solution Approach 1:
The patent inverts the electrode polarity configuration to make the lower electrode the address electrode. This inversion eliminates electrical cross-talk between adjacent nozzles while maintaining compatibility with standard positive-voltage driving circuits, thereby resolving both cost and interference issues simultaneously
3Productivity
If the piezoelectric element size is reduced to increase nozzle density, then printing resolution and speed improve, but displacement control becomes more difficult
Solution Approach 1:
The patent changes the electric field direction parameter by inverting the electrode configuration. This parameter change optimizes the interaction between the electric field and the oriented piezoelectric film, ensuring maximum displacement efficiency even in compact elements, thereby maintaining precision while enabling high-density nozzle arrangements
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 enables precise control of displacement direction and magnitude, reduces power consumption, and eliminates electrical cross-talk, resulting in improved inkjet head performance with higher resolution and faster printing speeds.
Implementation Method 1
piezoelectric film formed in epitaxial growth or oriented growth on an opposite side of the lower electrode to the diaphragm
Data Source
AI summary
A method of driving a piezoelectric actuator has the step of driving a piezoelectric actuator including a diaphragm, a lower electrode formed on one surface of the diaphragm, a piezoelectric film formed in epitaxial growth or oriented growth on an opposite side of the lower electrode to the diaphragm so as to be preferentially oriented in a (111) direction, and an upper electrode formed on an opposite side of the piezoelectric film to the lower electrode, by application of an electric field in a direction opposite to a direction of polarization of the piezoelectric film.