Piezoelectric Monoclinic Structure for Liquid Ejecting Head Wear Reduction
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Solution Overview
Problem
Piezoelectric elements in liquid ejecting heads experience a wear phenomenon where the polarization orientation becomes fixed, leading to a decrease in displacement amount and instability in liquid ejection due to repeated rotational expansion and contraction during operation.
Innovation Solution
A liquid ejecting head with a piezoelectric element featuring a perovskite structure piezoelectric material layer and a monoclinic structure, where the angle between the electric field direction and polarization orientation is optimized to reduce the rate of change in displacement, thereby minimizing the wear phenomenon and maintaining stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the piezoelectric material layer undergoes repeated rotational expansion and contraction during operation, then the liquid ejecting head can perform ejection function, but the polarization orientation becomes fixed following electric field application direction, resulting in decrease of piezoelectric displacement amount
Solution Approach 1:
The patent changes the crystal structure parameter of the piezoelectric material from a conventional structure to a monoclinic structure. This structural parameter change fundamentally alters the polarization behavior, preventing the wear phenomenon where polarization becomes fixed along the electric field direction, thereby maintaining stable displacement amount throughout the device lifecycle while preserving ejection functionality
Solution Approach 2:
The patent employs a composite piezoelectric material system with specific monoclinic crystal structure characteristics. This composite material design combines specific crystallographic features that enable both operational functionality and resistance to polarization wear, solving the contradiction between productivity and reliability
2Adaptability or versatility
If the piezoelectric displacement amount varies with use, then the device can adapt to operational changes, but stable ejection of liquid becomes difficult to achieve
Solution Approach 1:
By fundamentally changing the crystal structure parameter to monoclinic, the patent creates a piezoelectric material whose polarization orientation remains stable despite operational variations. This parameter change ensures that the displacement amount remains consistent throughout the device lifecycle, achieving both adaptability and ejection stability
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 orientation of the polarization moment in the piezoelectric material layer reduces the rate of change in displacement, ensuring stable and consistent ink ejection characteristics, enhancing the durability and reliability of the liquid ejecting head.
Implementation Method 1
a piezoelectric material layer made of a piezoelectric material exhibiting an electromechanical transducing function
Data Source
AI summary
A liquid ejecting head including a fluid channel forming substrate including a pressure generating chamber communicating with a nozzle opening that ejects a liquid droplet and a piezoelectric element. The piezoelectric element has a first electrode, a piezoelectric material layer that is provided on the first electrode and has a perovskite monoclinic structure, and a second electrode formed on the piezoelectric material layer opposite to the first electrode. An angle formed between a direction of an electric field generated between the first and second electrodes and an orientation of a polarization moment of the piezoelectric material layer is greater than an angle formed between the direction of the electric field at a time when the piezoelectric constant of the piezoelectric material layer reaches a maximum level and the orientation of the polarization moment.