Ring Electrode Piezoelectric Actuator for Fluid Ejection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing fluid ejection systems using piezoelectric actuators face challenges in achieving efficient volume displacement and reducing material fatigue, particularly due to the need for positive drive voltages and quiescent negative biases, which can lead to depolarization and reduced actuator effectiveness.
Innovation Solution
A fluid ejection system employing a dual electrode design with a ring-shaped drive electrode and a central electrode, where only negative drive voltages are applied, allowing the piezoelectric layer to remain in a neutral state, reducing fatigue, and enabling greater volume displacement with reduced drive voltage, thereby increasing nozzle density and membrane strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If positive drive voltages and quiescent negative biases are used in piezoelectric actuators, then fluid ejection can be achieved, but material fatigue and depolarization increase, reducing actuator effectiveness
Solution Approach 1:
The patent inverts the conventional voltage polarity approach by using only negative drive voltages instead of positive voltages with negative biases. The ring electrode configuration with negative voltage generates the necessary electric field to actuate the piezoelectric material, eliminating depolarization and material fatigue while maintaining fluid ejection capability
Solution Approach 2:
The patent changes the voltage parameter from bipolar (positive and negative) to unipolar (negative only). This parameter change, combined with the ring electrode geometry, transforms the electric field distribution to achieve membrane actuation without the harmful effects of positive voltages and quiescent biases
2Productivity
If conventional single electrode design is used, then device complexity is low, but volume displacement efficiency is insufficient, limiting nozzle density
Solution Approach 1:
The patent segments the electrode into two distinct components: a ring-shaped drive electrode and a central reference electrode. This segmentation creates separate functional zones that work together to generate enhanced electric field distribution, improving volume displacement efficiency and enabling higher nozzle density despite increased structural complexity
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
The dual electrode design enhances volume displacement efficiency, reduces material fatigue, and eliminates the need for positive drive voltages and quiescent biases, leading to improved performance and extended actuator lifespan.
Implementation Method 1
A piezoelectric actuator includes a layer of piezoelectric material that changes geometry (or actuates) in response to a voltage applied across the piezoelectric layer
Data Source
AI summary
Methods, systems, and apparatus for drive a pumping chamber of a fluid ejection system are disclosed. In one implementation, the actuator for drive the pumping chamber includes a continuous piezoelectric layer between a pair of drive electrodes and a continuous reference electrode. The pair of drive electrodes includes an inner electrode and an outer electrode surrounding the inner electrode. The actuator is further coupled to a controller which, during a fluid ejection cycle, applies a negative voltage pulse differential to the outer electrode to expand the pumping chamber for a first time period, then applies another negative voltage pulse differential to the inner electrode during a second time period after the first time period to contract the pumping chamber to eject a fluid drop.