Microfluidic Device Double Anodic Bonding Print Head Replacement

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Solution Overview

Problem

Existing microfluidic devices in organic vapor jet printing systems require destructive methods to replace print heads, leading to damage and contamination risks due to the use of adhesives and abrasive cleaning processes.

Innovation Solution

A microfluidic device with a metal plate and glass layer bonded via anodic bonding, allowing for easy replacement of print heads without breaking the adhesive bond, and a method for forming a double anodic bond to create a robust interfacial seal, enabling the interchangeability of print heads and fluid circuits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If adhesive bonding is used to attach print head to fixture, then bond strength at high temperature is improved, but replacement difficulty and contamination risk worsen

Engineering Contradiction:

Improvebond strengthVSAvoidprint head replacement

Core Design Contradiction:

StrengthVSEase of repair

Solution Approach 1:

The bonding system is segmented into two independent anodic bonds: one between the print head and intermediate layer, and another between the intermediate layer and fixture. This segmentation allows the print head to be detached by breaking only its bond to the intermediate layer, while the intermediate layer remains attached to the fixture, enabling easy replacement without damaging the fixture.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

An intermediate layer is introduced between the print head and fixture to act as a mediator. This intermediate layer receives the anodic bond from the print head on one side and another anodic bond from the fixture on the other side, allowing the print head to be replaced by detaching only from the intermediate layer while leaving the fixture intact.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Temperature

If adhesive bonding is used to attach print head to fixture, then high temperature bond strength is improved, but abrasive cleaning damage and contamination worsen

Engineering Contradiction:

Improvehigh temperature resistanceVSAvoidabrasive cleaning damage

Core Design Contradiction:

TemperatureVSObject-affected harmful factors

Solution Approach 1:

The mechanical adhesive bonding system is replaced with an anodic bonding system that uses electrochemical fields to create strong bonds at high temperatures. This substitution eliminates the need for mechanical abrasion during removal, as anodic bonds can be broken electrochemically without damaging the fixture surface.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The intermediate layer serves as a sacrificial mediator that protects the fixture from damage. When the print head needs replacement, only the bond between the print head and intermediate layer needs to be broken, avoiding any contact with abrasive cleaning tools on the fixture surface.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If reusable fixture is used with replaceable print heads, then cost efficiency is improved, but sealing reliability worsens

Engineering Contradiction:

Improvecost efficiencyVSAvoidsealing reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The intermediate layer is designed as a disposable component that remains attached to the expensive fixture. By sacrificing the intermediate layer during print head replacement, the system protects the fixture from damage, ensuring long-term sealing reliability while maintaining cost efficiency through reusable fixtures.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The intermediate layer acts as a protective mediator between the print head and fixture interfaces. It provides a stable bonding surface for the fixture while allowing easy print head replacement, maintaining sealing reliability through consistent anodic bonding interfaces.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

Enables the easy replacement and interchangeability of print heads, reducing contamination risks and maintaining high-temperature integrity, while eliminating the need for destructive adhesive removal and abrasive cleaning.

Implementation Method 1

The glass layer is directly bonded to the metal plate via an anodic bond

Methodology Applied

Scientific EffectAnodic bonding:

Implementation Method 2

applying a voltage across the stacked metal, glass, and silicon-based plates to form the double anodic bond

Methodology Applied

Scientific EffectAnodic bonding:

Data Source

PatentUS11761076B2Microfluidic device and method using double anodic bonding

Publication Date: 2023.09.19 THE RGT UNIV OF MICHIGAN

AI summary

A microfluidic device for use with a microfluidic delivery system, such as an organic vapor jet printing device, includes a glass layer that is directly bonded to a microfabricated die and a metal plate via a double anodic bond. The double anodic bond is formed by forming a first anodic bond at an interface of the microfabricated die and the glass layer, and forming a second anodic bond at an interface of the metal plate and the glass layer, where the second anodic bond is formed using a voltage that is lower than the voltage used to form the first anodic bond. The second anodic bond is formed with the polarity of the voltage reversed with respect to the glass layer and the formation of the first anodic bond. The metal plate includes attachment features that allow removal of the microfluidic device from a fixture.