Piezoelectric Layer Crystal Orientation for Liquid Jet Head Displacement
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Solution Overview
Problem
Existing liquid jet heads with piezoelectric elements suffer from unsatisfactory piezoelectric properties, particularly in terms of displacement and durability, even when using highly dielectric films, due to issues like delamination and fatigue during repeated rotation and extension/retraction of polarization.
Innovation Solution
A liquid jet head is designed with a channel-forming substrate and a piezoelectric element comprising a lower electrode, a perovskite-type crystal piezoelectric layer with a thickness of 5 μm or less, and an upper electrode, where the X-ray diffraction peak positions are optimized to improve displacement and durability, reducing the full width at half maximum of the X-ray diffraction peak to enhance piezoelectric properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a highly dielectric film is used to form a piezoelectric element, then the displacement property is improved, but the piezoelectric properties become unsatisfactory due to delamination and fatigue
Solution Approach 1:
The patent applies parameter changes by precisely controlling the thickness of the highly dielectric film to 5 μm or less and optimizing the X-ray diffraction peak interval to 2θ=9.059±0.1°. These parameter optimizations resolve the contradiction by achieving both sufficient displacement (3 nm or more) and reliable piezoelectric properties without delamination or fatigue issues
Solution Approach 2:
The patent uses a composite structure combining a piezoelectric film with a highly dielectric film layer. This composite material approach allows the system to achieve both good piezoelectric properties from the piezoelectric film and enhanced displacement from the highly dielectric film, while the optimized thickness and crystal orientation prevent delamination and fatigue
2Length of moving object
If the piezoelectric layer thickness is increased to improve displacement, then greater displacement is achieved, but durability decreases due to fatigue during repeated polarization rotation
Solution Approach 1:
The patent optimizes the thickness parameter of the highly dielectric film to 5 μm or less, which provides sufficient displacement (3 nm or more) while preventing the fatigue and durability issues that occur with thicker films during repeated polarization rotation and extension/retraction cycles
3Use of energy by moving object
If a piezoelectric element with low driving voltage is used, then energy consumption is reduced, but displacement becomes insufficient for high density arrangement
Solution Approach 1:
The patent employs a composite structure of piezoelectric film and highly dielectric film that enables the system to achieve large displacement (3 nm or more) while operating at low driving voltage (100 V or less). The highly dielectric film enhances the displacement property without requiring high voltage, resolving the contradiction between energy efficiency and displacement magnitude
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 optimized configuration enables the production of liquid jet heads with improved piezoelectric properties, including greater displacement with low driving voltage and reduced fatigue, resulting in excellent liquid jet performance.
Implementation Method 1
a piezoelectric element composed of a lower electrode, a piezoelectric layer, and an upper electrode and formed on the channel-forming substrate so that the pressure in the pressure-generating chamber can be changed
Implementation Method 2
a piezoelectric film made of a piezoelectric material having an electromechanical conversion function
Data Source
AI summary
A liquid jet head has a channel-forming substrate composed of a crystal substrate having a pressure-generating chamber linked to a nozzle opening as well as a piezoelectric element composed of a lower electrode, a piezoelectric layer, and an upper electrode and formed on the channel-forming substrate so that the pressure in the pressure-generating chamber can be changed, with the piezoelectric layer having a thickness equal to or smaller than 5 μm, made of a perovskite-type crystal, and formed so that the interval between the X-ray diffraction peak position derived from the (220) plane of the channel-forming substrate and the X-ray diffraction peak position derived from the (111) plane of the piezoelectric layer falls within the range 2θ=9.059±0.1°.