Liquid ejecting head and liquid ejecting apparatus

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Solution Overview

Problem

Existing piezoelectric-type liquid ejecting heads, such as those in JP-A-2013-256137, achieve only a doubling of displacement per unit voltage when stacking thin-film piezoelectric bodies, limiting further improvements in ejection characteristics and cost reduction.

Innovation Solution

A liquid ejecting head design with a specific orientation ratio of thin-film piezoelectric bodies, where the second thin-film piezoelectric body has a higher degree of orientation in the (100) or (110) plane compared to the first, and a voltage application circuit for applying reference and drive voltages, enhancing ejection performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If thin-film piezoelectric bodies are stacked in layers, then displacement amount per unit voltage is doubled, but ejection characteristics and cost reduction are still limited

Engineering Contradiction:

Improvedisplacement amount per unit voltageVSAvoidejection characteristics

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The patent applies different crystal orientations to different piezoelectric body layers. Specifically, the first piezoelectric body has a (100) plane orientation while the second piezoelectric body has a (110) plane orientation. This local differentiation of crystal structure properties allows each layer to contribute optimally to the overall displacement, achieving greater than doubled displacement per unit voltage compared to identical single-layer structures, thereby improving ejection characteristics.

Inventive Principle:

Principle #3Local quality

2Speed

If thin-film piezoelectric bodies are stacked in layers, then displacement amount per unit voltage is doubled, but further improvement in ejection characteristics is limited

Engineering Contradiction:

Improvedisplacement amount per unit voltageVSAvoidejection characteristics optimization

Core Design Contradiction:

SpeedVSEase of manufacture

Solution Approach 1:

The patent changes the crystal orientation parameter of the piezoelectric bodies to achieve superior performance. By setting the first piezoelectric body with (100) plane orientation and the second with (110) plane orientation, the invention optimizes the piezoelectric effect parameters to achieve displacement per unit voltage greater than twice that of single-layer structures, thereby improving ejection characteristics without complicating the manufacturing process.

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If thin-film piezoelectric bodies are stacked in layers, then cost reduction is achieved by replacement with parts of lower rated voltage, but ejection characteristics are still limited

Engineering Contradiction:

Improvecost reductionVSAvoidejection characteristics

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent uses a composite structure of piezoelectric bodies with different crystal orientations. The first piezoelectric body with (100) plane orientation and the second with (110) plane orientation work synergistically to produce a combined displacement effect that is greater than twice that of single-layer structures. This composite approach allows the use of lower rated voltage parts while achieving superior ejection characteristics, thereby reducing cost without compromising performance.

Inventive Principle:

Principle #40Composite materials

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 design achieves improved ejection characteristics and cost-effectiveness by optimizing the orientation and voltage application of thin-film piezoelectric bodies, leading to enhanced ejection performance and reduced operational costs.

Implementation Method 1

A piezoelectric method uses piezoelectric elements configured to cause a diaphragm constituting a part of wall surfaces of pressure compartments to vibrate. The liquid with which the pressure comparts are filled is ejected from nozzles by causing the diaphragm to vibrate by means of the piezoelectric elements.

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

a first thin-film piezoelectric body; an individual electrode which is provided individually for each of the plurality of pressure compartments and to which a drive voltage is applied; a second thin-film piezoelectric body

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentUS20250303716A1Liquid ejecting head and liquid ejecting apparatus

Publication Date: 2025.10.02 SEIKO EPSON CORP

AI summary

Wherein the pressure compartment substrate, the diaphragm, the first common electrode, the first thin-film piezoelectric body, the individual electrode, the second thin-film piezoelectric body, and the second common electrode are stacked in this order from a lower side toward an upper side, and a first ratio, which is a ratio of a degree of orientation in a plane to a degree of orientation in a plane, of the second thin-film piezoelectric body is greater than the first ratio of the first thin-film piezoelectric body.