Piezoelectric Device with Uniform dC/dV for Liquid Discharge
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Solution Overview
Problem
Piezoelectric devices used in liquid discharge heads experience reduced deformation and displacement due to variations in dielectric characteristics, leading to inefficient liquid discharge.
Innovation Solution
A piezoelectric device with a piezoelectric body containing lead zirconate titanate (PZT) ceramics, a vibration plate, and electrodes, where the change in capacitance (dC/dV value) across the active portion is 10% or less, improving deformation and displacement through controlled Pb molar concentration and layer structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional piezoelectric body is used, then the device structure is simple, but the amount of deformation and displacement decreases due to variation in dielectric characteristics
Solution Approach 1:
The patent applies local quality by creating a composite piezoelectric body where different regions have different Pb concentrations. The first piezoelectric layer has a higher Pb concentration (1.10 to 1.30 times) than the second piezoelectric layer, allowing local optimization of dielectric characteristics in the active portion while maintaining overall structural simplicity. This gradient structure ensures uniform dC/dV values across the piezoelectric body thickness direction.
Solution Approach 2:
The patent uses composite materials by combining two piezoelectric layers with different Pb concentrations into a single piezoelectric body. This composite structure allows the first piezoelectric layer to provide enhanced piezoelectric distortion in the active portion while the second piezoelectric layer provides structural support, achieving both improved deformation uniformity and maintained structural integrity.
2Strength
If the piezoelectric body has uniform composition, then manufacturing is easier, but the amount of deformation due to piezoelectric distortion is insufficient
Solution Approach 1:
The patent implements local quality by concentrating higher Pb content in the first piezoelectric layer corresponding to the active portion, while the second piezoelectric layer has lower Pb content. This localized enhancement of piezoelectric properties in the active region increases the amount of deformation due to piezoelectric distortion without requiring complex manufacturing processes, as the layering can be achieved through sequential deposition or sintering.
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
Enhances the amount of deformation and displacement of the vibration plate, leading to improved liquid discharge efficiency in the piezoelectric device.
Implementation Method 1
displaces the vibration plate by deforming a piezoelectric body due to piezoelectric distortion of the movable portion
Implementation Method 2
a change width of a dC/dV value, which represents a change in capacitance with respect to a change in a voltage applied
Data Source
AI summary
A piezoelectric device includes a piezoelectric body, a vibration plate that vibrates when the piezoelectric body is driven, a first electrode positioned between the piezoelectric body and the vibration plate, and a second electrode positioned to be separated from the first electrode by the piezoelectric body. The piezoelectric body has an active portion that is a part sandwiched between the first electrode and the second electrode in a first direction along a thickness direction of the piezoelectric body, and a change width of a dC/dV value, which represents a change in capacitance with respect to a change in a voltage applied along a second direction orthogonal to the first direction, from one end of the active portion on a side of the first electrode to the other end of the active portion on a side of the second electrode in the first direction is 10% or less.