Liquid Discharge Head Insulation via Columnar Wiring

Solution Overview

Problem

Existing liquid discharge heads face challenges in balancing insulation properties and vibration plate displacement, as increased insulation thickness enhances insulation but reduces vibration plate displacement, while reduced thickness leads to leakage between electrodes.

Innovation Solution

The liquid discharge head design includes a piezoelectric element with a lamination structure and a lead-out wiring routed along the wall surface of a column portion within the protective substrate, eliminating the need for an insulating layer between the lead-out wiring and the first electrode, thereby maintaining insulation while ensuring vibration plate displacement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the thickness of the insulating layer between the lead-out wiring and the first electrode is increased, then the insulation property between the lead-out wiring and the first electrode is enhanced, but the displacement amount of the vibration plate reduces

Engineering Contradiction:

Improveinsulation propertyVSAvoiddisplacement amount of vibration plate

Core Design Contradiction:

ReliabilityVSLength of moving object

Solution Approach 1:

The lead-out wiring is routed along the side surface of the columnar projection in the thickness direction rather than on the upper surface parallel to the first electrode. This three-dimensional routing approach eliminates the need for a thick insulating layer while maintaining adequate insulation distance, thereby preserving the vibration plate's displacement amount.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The columnar projection serves as an intermediary structure that provides a side surface for routing the lead-out wiring. This intermediate structure enables the wiring to be positioned at an adequate distance from the first electrode without requiring a thick insulating layer, thus resolving the contradiction between insulation requirements and vibration plate displacement.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Length of moving object

If the thickness of the insulating layer between the lead-out wiring and the first electrode is decreased, then the displacement amount of the vibration plate is maintained, but leakage between the lead-out wiring and the first electrode occurs easily

Engineering Contradiction:

Improvedisplacement amount of vibration plateVSAvoidinsulation property

Core Design Contradiction:

Length of moving objectVSReliability

Solution Approach 1:

The lead-out wiring is routed along the side surface of the columnar projection in the thickness direction rather than on the upper surface parallel to the first electrode. This three-dimensional routing approach eliminates the need for a thick insulating layer while maintaining adequate insulation distance, thereby preserving the vibration plate's displacement amount.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The columnar projection serves as an intermediary structure that provides a side surface for routing the lead-out wiring. This intermediate structure enables the wiring to be positioned at an adequate distance from the first electrode without requiring a thick insulating layer, thus resolving the contradiction between insulation requirements and vibration plate displacement.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of manufacture

If the lead-out wiring is routed on the upper surface of the first electrode, then the wiring layout is simplified, but an insulating layer must be provided which reduces vibration plate displacement

Engineering Contradiction:

Improvewiring layoutVSAvoiddisplacement amount of vibration plate

Core Design Contradiction:

Ease of manufactureVSLength of moving object

Solution Approach 1:

The lead-out wiring is routed along the side surface of the columnar projection in the thickness direction rather than on the upper surface parallel to the first electrode. This three-dimensional routing approach eliminates the need for a thick insulating layer while maintaining adequate insulation distance, thereby preserving the vibration plate's displacement amount.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 ensures effective insulation between electrodes without reducing vibration plate displacement, reducing parasitic capacitance and power consumption, and minimizing electric crosstalk, while preventing leakage.

Implementation Method 1

a piezoelectric element having a lamination structure in which a first electrode, a piezoelectric body layer, and a second electrode are laminated in this order

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentUS10773523B2Liquid discharge head, liquid discharge apparatus, and piezoelectric device

Publication Date: 2020.09.15 SEIKO EPSON CORP

AI summary

A liquid discharge head includes: a pressure chamber communicating with a nozzle through which liquid is discharged; a piezoelectric element having a lamination structure in which a first electrode, a piezoelectric body layer, and a second electrode are laminated in this order; a vibration plate installed between the first electrode of the piezoelectric element and the pressure chamber; a protective substrate in which an internal space for housing the piezoelectric element is formed; and a lead-out wiring connected to the second electrode, in which a column portion is provided at a position overlapping with the piezoelectric element in the internal space of the protective substrate when viewed in a plan view, and the lead-out wiring is provided on a wall surface of the column portion.