Piezoelectric Element Drive Stabilizing Polarization for Liquid Ejection
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Solution Overview
Problem
Piezoelectric element drive methods for liquid ejecting devices face challenges in maintaining stable ejection force due to degradation of polarization characteristics and hysteresis curves, especially when using soft materials, leading to inconsistent displacement characteristics and ejection performance.
Innovation Solution
A method involving a drive circuit that applies a pre-drive voltage higher than the highest voltage of the drive voltage waveform to the piezoelectric element before applying the drive voltage waveform, stabilizing the state of polarization and enhancing displacement robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a bias voltage is selected to maximize the displacement amount of a piezoelectric element, then ejection force is increased, but polarization characteristics degrade and displacement characteristics become unstable
Solution Approach 1:
The patent applies a pre-drive voltage higher than the highest drive voltage before applying the drive voltage waveform. This preliminary action restores the polarization state of the piezoelectric element, ensuring stable displacement characteristics while maintaining large ejection force. The pre-drive voltage prepares the element in advance, preventing polarization degradation during subsequent operation.
2Force
If soft piezoelectric materials are used to produce large displacement amounts, then ejection force is increased, but hysteresis and creep phenomena cause unstable displacement characteristics
Solution Approach 1:
The pre-drive voltage applied before the drive waveform restores the polarization state of soft piezoelectric materials, compensating for hysteresis and creep effects. This ensures consistent displacement characteristics while maintaining the large ejection force provided by soft materials.
Solution Approach 2:
The patent changes the voltage parameter by applying a pre-drive voltage higher than the maximum drive voltage. This parameter change restores the polarization state and stabilizes displacement characteristics, allowing soft materials to maintain consistent performance despite their inherent hysteresis and creep properties.
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 ensures a large and stable displacement amount of the piezoelectric element, improving the robustness and consistency of ejection force, even when using soft materials, by recovering the state of polarization and minimizing the impact of hysteresis and creep phenomena.
Implementation Method 1
a piezoelectric element that operates as part or all of the walls thereof is deformed by applying a voltage to the element
Implementation Method 2
applying a pre-drive voltage to the piezoelectric element prior to applying the drive voltage waveform; the pre-drive voltage being higher than the highest voltage of the drive voltage waveform
Data Source
AI summary
Liquid is forced to be ejected from a liquid chamber as a drive voltage is applied to the piezoelectric element that forms part or all of the walls of the liquid chamber by means of a drive circuit to deform the piezoelectric element. The drive circuit applies a pre-drive voltage to the piezoelectric element prior to the application of the drive voltage waveform for driving the piezoelectric element. The pre-drive voltage is higher than the highest voltage level of the drive voltage waveform.