Piezoelectric Layer Polarization for Liquid Ejecting Heads

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing liquid ejecting heads, such as ink jet recording heads, face challenges in achieving uniform polarization of piezoelectric layers without requiring high energy, which can lead to layer deterioration or breakage due to high electric fields.

Innovation Solution

A method for producing liquid ejecting heads with a piezoelectric element that includes a polarization process using an electric field with a strength higher than required for converting polarization from the <001> to the <111> direction but lower than required for conversion to the <001> direction, preventing the piezoelectric layer from entering a paraelectric state and maintaining low energy usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a high electric field is applied to the piezoelectric layer during initialization to make polarization moments uniform, then piezoelectric properties are improved, but the piezoelectric layer may deteriorate or breakage due to high energy consumption

Engineering Contradiction:

Improvepiezoelectric propertiesVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies a high electric field strength (10-100 kV/cm) during the polarization process to align polarization moments uniformly in the piezoelectric layer, thereby improving piezoelectric properties. This parameter change in electric field strength resolves the contradiction by providing sufficient energy for polarization alignment while maintaining reliability through controlled application conditions.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If a high electric field is applied to the piezoelectric layer during initialization, then polarization moments are made uniform, but the cost increases due to high energy consumption

Engineering Contradiction:

Improveuniform polarizationVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent specifies a controlled electric field strength range (10-100 kV/cm) and applies it for a limited duration (1-60 seconds) to achieve uniform polarization. By optimizing these parameters, the process achieves reliable polarization alignment while minimizing energy consumption and manufacturing costs.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If a high electric field is applied to the piezoelectric layer, then polarization is initialized, but the piezoelectric layer may breakage due to high energy

Engineering Contradiction:

Improvepolarization initializationVSAvoidlayer integrity

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent carefully controls the electric field strength within a specific range (10-100 kV/cm) and limits the application time (1-60 seconds). This parameter optimization ensures sufficient polarization initialization while preventing excessive stress that could cause layer breakage, thus maintaining structural integrity.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies the high electric field in a controlled manner with predetermined time and strength parameters, effectively cushioning against the potential harmful effects of excessive energy application. This pre-planned controlled approach prevents layer breakage while achieving the desired polarization initialization.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 approach reduces the cost and risk of piezoelectric layer damage while enhancing piezoelectric properties and durability, enabling efficient and reliable liquid ejecting performance at a lower energy consumption.

Implementation Method 1

a piezoelectric element having a first electrode, a piezoelectric layer, and a second electrode, and that causes pressure changes in a pressure generating chamber communicating with a nozzle opening

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

a polarization process of polarizing the piezoelectric layer by applying an electric field having energy higher than energy required for converting the polarization direction in the <001> direction to the <111> direction

Methodology Applied

Scientific EffectPolarization: Polarisation

Data Source

PatentUS8197034B2Method for producing liquid ejecting head, liquid ejecting head, and liquid ejecting device

Publication Date: 2012.06.12 SEIKO EPSON CORP

AI summary

A liquid ejecting head has a piezoelectric element with a first electrode, a piezoelectric layer, and a second electrode. The liquid ejecting head causes pressure changes in a pressure generating chamber communicating with a nozzle opening. The piezoelectric layer has a perovskite structure and is preferentially orientated in a (100) plane. A method for producing the liquid ejecting head includes polarizing the piezoelectric layer by applying an electric field having energy higher than energy required for converting the polarization direction in the <111> direction to the <110> direction and lower than energy required for converting the polarization direction in the <111> direction to the <001> direction when the electric field to be applied to the piezoelectric layer is in the <001> direction vertical to a plane on which the second electrode is provided.