Piezoelectric Inkjet Head Bypass Trace Electrical Reliability

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Solution Overview

Problem

In ink-jet heads, electric disconnection due to insufficient conductive material in through holes can disrupt the supply of electric charge, making it difficult to maintain consistent electrical connection and reliable operation.

Innovation Solution

A liquid discharge head design featuring a piezoelectric body with a bypass trace and extending portions of the common electrode, connected by conductive material in through holes, allowing for alternative electrical paths to ensure charge supply even if one through hole is disconnected.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conductive material is filled in through holes to connect electrodes, then electrical connection reliability is improved, but manufacturing precision deteriorates due to insufficient material filling

Engineering Contradiction:

Improveelectrical connection reliabilityVSAvoidconductive material filling precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The common electrode is divided into multiple segments (first common electrode, second common electrode, third common electrode) that are electrically connected through through holes. This segmentation allows the electrical connection path to be distributed across multiple points, so that if one through hole has insufficient conductive material, other paths remain available to maintain overall electrical connection reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The design anticipates potential manufacturing defects by creating redundant electrical connection paths through multiple through holes and electrode segments. This beforehand cushioning ensures that even if some through holes have insufficient conductive material filling, the electrical connection is maintained through alternative paths, compensating for the manufacturing precision shortfall.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If multiple through holes are used to ensure electrical connection, then reliability is improved, but device complexity increases

Engineering Contradiction:

Improveelectrical connection reliabilityVSAvoidelectrode structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Multiple electrode segments (first common electrode, second common electrode, third common electrode) are merged into a single functional common electrode that serves multiple purposes: providing electrical connection, defining pressure chamber boundaries, and enabling liquid discharge. This merging reduces device complexity while maintaining the reliability benefits of multiple connection paths.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The common electrode structure serves multiple functions simultaneously: it provides electrical connection through multiple segments, defines the boundaries of pressure chambers, and enables liquid discharge through its openings. This multi-functionality reduces the need for separate components, thereby reducing device complexity while maintaining electrical connection reliability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 enhances the reliability of electrical connections by enabling charge supply through alternative paths, reducing the impact of conductive material insufficiency and improving the overall operational consistency of the ink-jet head.

Implementation Method 1

there is a publicly-known ink-jet head having a piezoelectric body in which a plurality of piezoelectric material layers (ceramics sheets) are layered or stacked

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

A plurality of through holes are formed between the surface electrode and the common electrode, and a conductive material charged (filled) in the plurality of through holes allows the surface and common electrodes to electrically conducted with each other

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS10814627B2Liquid discharge head

Publication Date: 2020.10.27 BROTHER KOGYO KK

AI summary

There is provided a liquid discharge head including: a piezoelectric body, a common electrode, a bypass trace, and a plurality of individual electrodes. The piezoelectric body is provided with: a first through hole extending in a stacking direction between a conductive layer constructing the piezoelectric body and a first extending portion of the common electrode, and a second through hole extending in the stacking direction between the conductive layer and the first extending portion. The conductive layer and the first extending portion are electrically connected to each other by a conductive material arranged in the first and second through holes.