Planar Fluid Ejection Actuators via Conductive Layer Treatment
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Solution Overview
Problem
Resistive fluid ejection actuators in micro-fluid ejection devices, such as thermal ink jet printers, are prone to mechanical damage from cavitation and thermal gradients due to non-planar topographies, leading to premature failure of protective film layers.
Innovation Solution
A micro-fluid ejection actuator structure with a conductive layer having a substantially non-conductive portion, treated to have low conductivity properties, and a resistive layer adjacent to it, eliminating the need for etching and resulting in a planar topography, thereby reducing mechanical and thermal stresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional thick conductor layer is used for the resistive fluid ejection actuator, then electrical connectivity is ensured, but non-planar topography is created causing stress risers and mechanical damage
Solution Approach 1:
The conductor layer is selectively treated to create a non-conductive portion only where the actuator pad should be, while maintaining conductivity in the electrode regions. This localized modification eliminates non-planar topography at the actuator pad area without compromising electrical connectivity in the conductor layer elsewhere.
2Ease of manufacture
If the conductor layer is etched to create heater pad area, then the actuator structure is formed, but non-planar structure results requiring thicker protective layers
Solution Approach 1:
Instead of removing conductor material through etching to create the heater pad area, the invention extracts or deactivates conductivity in the specific region where the actuator pad should be. This is achieved by treating the conductor layer to create a non-conductive portion, thereby forming the actuator structure without physical removal of material and maintaining planarity.
3Use of energy by moving object
If thinner protective layers are used to increase thermal efficiency, then energy efficiency improves, but mechanical failure risk increases due to weak areas in the film layers
Solution Approach 1:
The conductor layer itself is modified beforehand to provide mechanical support and stress distribution. By creating a non-conductive portion in the conductor layer, a structurally sound base is established that can support thinner protective layers without creating stress risers, thereby cushioning against mechanical failure before it occurs.
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 solution enhances the durability and longevity of micro-fluid ejection devices by preventing mechanical failure and allowing for thinner protective layers that increase energy efficiency.
Implementation Method 1
The exposed selected portion of the conductive layer is treated to transform the selected portion into a portion having low conductivity properties to provide a substantially non-conductive portion
Implementation Method 2
The fluid droplets are expelled from a conventional thermal micro-fluid ejection head when a pulse of electrical current flows through the fluid ejection actuator, vaporizing a small portion of the fluid to create a bubble
Implementation Method 3
Such non-homogenities may also result from the thermal gradient between the relatively hot center of the resistive actuator pad and the relatively cool edges
Implementation Method 4
Resistive fluid ejection actuators are prone to mechanical damage from cavitation as the bubble collapses after drop ejection
Data Source
AI summary
Fluid ejection actuators, micro-fluid ejection heads, and methods relating thereto. One such fluid ejection actuator is provided by a conductive layer adjacent a substrate. The conductive layer has a substantially non-conductive portion. The substantially non-conductive portion includes a portion of the conductive layer which has been treated to have low conductivity properties. A resistive layer is adjacent the conductive layer. The substantially non-conductive portion of the conductive layer substantially defines the fluid ejection actuator.