Piezoelectric Actuator Adhesive Bonding for Inkjet Printheads

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Solution Overview

Problem

Existing piezoelectric actuators in inkjet printheads face challenges in achieving a strong and reliable adhesive bond between the piezoelectric material and the membrane, which affects the transfer of mechanical energy and the efficiency of ink ejection.

Innovation Solution

A new rough structure and fabrication process involving a conductor with a root mean square surface roughness of at least 10nm, specifically using a nickel or nickel alloy coated with tin, is developed to enhance the adhesive bond between the piezoelectric material and the membrane, forming a composite nickel/tin film that stabilizes through annealing for improved mechanical energy transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If piezoelectric materials are used in orthodontic appliances, then tooth movement control is improved, but the complexity of the appliance increases

Engineering Contradiction:

Improvetooth movement controlVSAvoidappliance complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines multiple functions into a single integrated appliance structure. The retainer component incorporates both passive retention features and active piezoelectric tooth movement control in one device, eliminating the need for separate appliances and reducing overall system complexity while maintaining precise control capability

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The retainer is designed to perform multiple functions simultaneously: it provides passive retention to maintain tooth position, incorporates piezoelectric actuators for active tooth movement control, and includes sensor integration for monitoring. This multi-functionality reduces the number of separate components needed in the orthodontic system

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Device complexity

If conventional orthodontic appliances are used, then the device complexity is low, but tooth movement precision deteriorates

Engineering Contradiction:

Improveappliance complexityVSAvoidtooth movement precision

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent replaces conventional passive mechanical orthodontic appliances with an active system using piezoelectric actuators. These actuators convert electrical signals into precise mechanical movements, enabling controlled tooth displacement with micrometer-level precision that far exceeds conventional mechanical appliance capabilities

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system enables dynamic adjustment of tooth movement parameters including force magnitude, direction, and rate of movement. By controlling the piezoelectric actuators through electrical parameters, the system can precisely regulate tooth movement within physiological limits, achieving optimal orthodontic outcomes that conventional fixed appliances cannot provide

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If piezoelectric actuators are integrated into retainers, then tooth movement control is improved, but manufacturing complexity increases

Engineering Contradiction:

Improvetooth movement controlVSAvoidmanufacturing complexity

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent incorporates piezoelectric actuators and control electronics into the retainer during the manufacturing process rather than as separate assembly steps. The retainer is designed with integrated mounting features and channels for the actuators, allowing them to be installed and configured before final assembly, thereby simplifying the overall manufacturing workflow

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The design nests the piezoelectric actuators within the retainer structure itself. The actuators are positioned in dedicated cavities or channels formed as part of the retainer geometry, eliminating the need for separate mounting hardware and reducing assembly steps. This nested integration approach streamlines manufacturing while maintaining precise actuator positioning

Inventive Principle:

Principle #7Nested doll (Nesting)

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 enhanced adhesive bond leads to improved mechanical energy transfer and robust ink ejection in piezoelectric actuators, increasing the reliability and efficiency of inkjet printheads and potentially other MEMS devices.

Implementation Method 1

a piezoelectric actuator is integrated into the retainer. The piezoelectric actuator has a first end and a second end. The piezoelectric actuator is configured to move the tooth root in a controlled manner in response to an electrical signal

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP2828082B1Piezoelectric actuator and method of making a piezoelectric actuator

Publication Date: 2020.01.15 HEWLETT PACKARD DEVELOPMENT COMPANY LP

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AI summary

In one example, a piezoelectric actuator includes a piezoelectric material, a first conductor on a first part of the piezoelectric material, and a membrane bonded to the first conductor with an adhesive. The first conductor has a root mean square surface roughness of at least 10nm at the bonding interface with the membrane.