Conduction Structure for Droplet Ejecting Head High-Density Wiring
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Solution Overview
Problem
Existing conduction structures in droplet ejecting heads face challenges in achieving high-density wiring due to the isotropic growth of plating metal, leading to increased electrical resistance and difficulty in reducing the size of the droplet ejecting head and printing apparatus.
Innovation Solution
A conduction structure with a first substrate and a second substrate having non-parallel main and end surfaces, where the conductive layer is formed on the end surface to connect the substrates, allowing for high-density wiring and reduced size, and a method involving metallic film formation and patterning using sputtering and photolithographic methods to achieve low electrical resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If plating metal is grown isotropically by electroless plating method to join separated connection terminals, then electrical connection is achieved, but the plating metal widely expands in the width direction causing adjacent connection terminals to short circuit, preventing high arrangement density
Solution Approach 1:
The patent applies preliminary action by forming a conductive layer on the end surface of the substrate before joining the connection terminals. This pre-formed conductive structure guides the plating metal growth directionally, preventing isotropic expansion and short circuits, thereby enabling high arrangement density while ensuring reliable electrical connection.
Solution Approach 2:
The patent implements local quality by creating a conductive layer specifically on the end surface where connection is needed, rather than uniform plating across the entire substrate. This localized conductive structure controls plating metal growth only in the necessary area, preventing unwanted expansion and enabling higher terminal density.
2Reliability
If connection terminals are separated to prevent short circuiting during plating, then electrical isolation is maintained, but the arrangement density of connection terminals cannot be sufficiently increased
Solution Approach 1:
The patent introduces a conductive layer as an intermediary structure on the end surface that enables controlled electrical connection. This intermediary guides the plating metal growth directionally, allowing connection terminals to be placed closer together without causing short circuits, thereby achieving both electrical isolation and high arrangement density.
3Volume of moving object
If electric wiring and connection terminals are densely arranged to reduce droplet ejecting head size, then miniaturization is achieved, but the time required for adhesion of driver IC increases
Solution Approach 1:
The patent applies preliminary action by pre-forming the conductive layer on the end surface of the substrate before mounting the driver IC. This preparation creates ready-to-connect structures that simplify the adhesion process, allowing dense wiring arrangement and miniaturization without significantly increasing adhesion time.
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 enables the formation of high-density, low-resistance wiring patterns, facilitating a smaller and more reliable droplet ejecting head and printing apparatus with improved manufacturability and operational efficiency.
Implementation Method 1
forming a metallic film on the end surface; wherein the metallic film is formed by a sputtering method
Implementation Method 2
patterning the metallic film by a photolithographic method
Data Source
AI summary
A conduction structure includes a device substrate (first substrate), an IC (second substrate) having an upper surface and an end surface, a sealing plate (third substrate) having an upper surface and an end surface, a conductive layer having a first part provided on an upper surface of the device substrate, a second part provided on the end surface of the IC and connected to the first part, a third part provided on the upper surface of the IC and connected to the second part, and a fourth part provided on the end surface of the sealing plate and connected to both of the first part and the second part, and a plating layer overlapped with the conductive layer.