Liquid Ejection Head with Embedded Power Wiring
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing liquid ejection heads face inefficiencies in thermal energy transmission to droplets due to the need for thick passivation and anti-cavitation films to cover wire level differences, leading to poor ejection efficiency.
Innovation Solution
A liquid ejection head design with wires embedded in the insulating layer, eliminating wire-level differences, allowing for a thinner protective layer and improved thermal energy transfer to droplets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the passivation film and anti-cavitation film are formed to have the same thickness as the level difference caused by wires, then the heating resistance element surface is sufficiently protected, but thermal energy cannot be efficiently transmitted to liquid droplets resulting in poor ejection efficiency
Solution Approach 1:
The patent transitions from a planar wire configuration to a three-dimensional recess structure. Wires are embedded in recesses formed on the heating resistance element surface, allowing the protective film to be thin over the heating element while maintaining adequate coverage over wire connections in the recessed areas. This dimensional change resolves the contradiction by enabling both surface protection and efficient thermal transmission.
2Ease of manufacture
If wires are connected to both the temperature detecting element and heating resistance element on the surface, then electrical connections are established, but a two-level difference is formed on the heating resistance element requiring thick insulating films
Solution Approach 1:
The patent applies nesting by placing wires inside recesses formed on the heating resistance element surface. The recesses act as cavities that accommodate the wires, allowing electrical connections to be established while maintaining a relatively flat overall surface. This nested configuration eliminates the need for thick level-difference-covering films, as the wires are contained within the recessed structures rather than protruding above the surface.
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 ejection efficiency by ensuring efficient thermal energy transmission to liquid droplets, improving the overall performance of the liquid ejection head.
Implementation Method 1
an energy generating element provided in contact with a surface of the insulating layer for generating thermal energy for ejecting liquid
Implementation Method 2
a temperature detecting element provided inside the insulating layer and provided so as to at least partly overlap the energy generating element
Implementation Method 3
thermal energy emitted from the heating resistance element cannot be efficiently transmitted to a droplet of liquid such as ink because the film thickness needs to be as great as the level difference
Data Source
AI summary
A liquid ejection head and its manufacturing method are capable of reducing the thickness of a protective layer as compared to the traditional technique so as to efficiently transfer the heat energy generated by a heating resistance element to a droplet of liquid such as ink. To achieve this, power supply wirings are provided in the same layer below the heating resistance element.