Piezoelectric Layer Titanium Concentration Gradient for Crack Prevention
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Solution Overview
Problem
The existing manufacturing processes for piezoelectric layers in liquid jet heads often result in cracks due to inappropriate manufacturing conditions, affecting the crystalline properties and durability of the piezoelectric elements, which is a common issue in both liquid jet heads and other piezoelectric apparatuses.
Innovation Solution
A liquid jet head configuration is developed with a piezoelectric layer composed of ferroelectric films containing lead (Pb), zirconium (Zr), and titanium (Ti), where the boundary portion between the first and second ferroelectric films has a maximum titanium concentration of 80% or more, and between subsequent films, the concentration ranges from 35 to 60%, optimizing the crystallization and reducing crack occurrence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional manufacturing processes are used to form piezoelectric layers, then the manufacturing process is simple, but cracks occur in the piezoelectric layer affecting durability
Solution Approach 1:
The patent applies local quality by creating a specific titanium concentration distribution at the boundary portion between ferroelectric films. The boundary portion has a maximum titanium concentration of 80% or more, while other regions have different concentrations (35-60% for subsequent films). This localized compositional variation at critical interfaces prevents cracks without requiring changes to the entire piezoelectric layer structure.
Solution Approach 2:
The patent changes the chemical composition parameter by controlling titanium concentration at different locations within the piezoelectric layer. By adjusting the titanium concentration to 80% or more at boundary portions and 35-60% in other regions, the patent modifies the material properties to prevent crack formation while maintaining manufacturability through controlled deposition parameters.
2Reliability
If titanium concentration is increased to prevent cracks, then durability improves, but manufacturing precision requirements increase
Solution Approach 1:
The patent specifies precise titanium concentration ranges for different regions: 80% or more at boundary portions and 35-60% in other regions. This localized quality control focuses manufacturing precision requirements only where needed (at interfaces between films) rather than requiring uniform precision throughout the entire layer, making the manufacturing process more feasible.
Solution Approach 2:
The patent defines specific parameter ranges for titanium concentration that balance crack prevention with manufacturing feasibility. By setting the boundary portion titanium concentration at 80% or more and other regions at 35-60%, the patent establishes controllable target values that improve reliability while maintaining reasonable manufacturing precision requirements.
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 configuration effectively reduces crack occurrence in the piezoelectric layer, improving the yield and durability of the liquid jet head, while enhancing the displacement characteristics of the piezoelectric elements.
Implementation Method 1
a piezoelectric element which includes a first electrode formed above the flow passage forming substrate, a piezoelectric layer formed above the first electrode, and a second electrode formed above the piezoelectric layer
Data Source
AI summary
A piezoelectric layer is formed of a plurality of ferroelectric films containing lead (Pb), zirconium (Zr), and titanium (Ti) above a first electrode. A boundary portion between a first ferroelectric film closest to the first electrode and a second ferroelectric film formed above the first ferroelectric film has an area where the maximum value of a concentration of titanium with respect to zirconium is 80% or more.