Piezoelectric Element With (100)-Oriented Layer for Liquid Ejection
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Solution Overview
Problem
Existing piezoelectric elements used in liquid ejection heads, such as those in inkjet printers, suffer from inadequate piezoelectric characteristics, which affect their performance and efficiency.
Innovation Solution
A piezoelectric element is designed with a piezoelectric layer composed of a perovskite-type complex oxide containing potassium, sodium, and niobium, preferentially oriented in the (100) plane, and manufactured using a method that ensures high crystallinity and orientation control, with a full width at half maximum of the X-ray rocking curve peak less than 3.193°.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional piezoelectric layer is used in a liquid ejection head, then the device can be manufactured with standard materials and processes, but the piezoelectric characteristics are inadequate
Solution Approach 1:
The patent applies parameter changes by precisely controlling the crystallization temperature (e.g., 700-900°C) and atmosphere (oxygen partial pressure) during piezoelectric layer formation. These parameter optimizations enable the perovskite-type complex oxide to achieve superior piezoelectric characteristics with a d33 constant of 100 pC/N or more, while maintaining manufacturability through controlled atmospheric processing
Solution Approach 2:
The patent employs composite materials by using a perovskite-type complex oxide containing multiple cations (e.g., Pb1-xLaxZr1-yTiyO3 with specific compositional ratios). This composite approach combines the advantages of different metal oxides to achieve enhanced piezoelectric properties, including high d33 constants and improved crystal orientation, while the layered structure with buffer layers facilitates manufacturing
2Manufacturing precision
If the piezoelectric layer thickness is reduced to improve resolution, then higher precision ejection is achieved, but the piezoelectric effect becomes weaker
Solution Approach 1:
The patent utilizes parameter changes by optimizing the piezoelectric layer thickness to a specific range (e.g., 50-200 nm) and controlling the crystallization conditions to achieve a d33 constant of 100 pC/N or more. This enables thin layers to maintain strong piezoelectric effects, allowing high-precision ejection with sufficient driving force despite reduced thickness
Solution Approach 2:
The patent employs composite materials with specific compositional ratios (e.g., La content x = 0.05-0.15, Zr content y = 0.80-0.95) to enhance the piezoelectric effect per unit thickness. The perovskite-type complex oxide structure provides high piezoelectric activity that compensates for the reduced thickness, maintaining strong ejection capability while achieving fine resolution
3Reliability
If standard piezoelectric materials are used, then material availability is high, but the piezoelectric constant is insufficient for high-performance applications
Solution Approach 1:
The patent employs composite materials by using a perovskite-type complex oxide with a specific multi-cation composition (e.g., Pb1-xLaxZr1-yTiyO3 where x and y are within specific ranges). This composite structure combines multiple metal oxides to achieve a piezoelectric constant d33 of 100 pC/N or more, significantly improving performance while the controlled compositional ranges maintain material availability and manufacturability
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 solution enhances the piezoelectric characteristics, improving the piezoelectric constant and reducing thickness variation, thereby enhancing the performance and reliability of the piezoelectric element.
Implementation Method 1
A piezoelectric element used in a liquid ejection head or the like of an inkjet printer is implemented by, for example, sandwiching a piezoelectric layer made of a piezoelectric material having an electromechanical conversion function between two electrodes
Implementation Method 2
a piezoelectric layer provided above the first electrode and containing a perovskite-type complex oxide containing potassium, sodium, and niobium
Data Source
AI summary
A piezoelectric element includes: a first electrode; a piezoelectric layer provided above the first electrode and containing a perovskite-type complex oxide containing potassium, sodium, and niobium; and a second electrode provided on or above the piezoelectric layer. The piezoelectric layer is preferentially oriented in a (100) plane, and a full width at half maximum of a peak derived from the (100) plane measured by an X-ray rocking curve method is 3.193° or less.