Penetration Wiring Taper for Liquid Ejecting Head
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As liquid ejecting heads miniaturize, forming a sufficient adhesive layer inside penetration holes with high aspect ratios becomes challenging, leading to concerns of conductor protrusion or slipping due to thermal expansion differences and external forces.
Innovation Solution
A liquid ejecting head design featuring a penetration wiring with a smaller cross-sectional area connection section, formed using an electrolytic plating technique, which increases in cross-sectional area towards the substrate surfaces, and a manufacturing method that includes forming recessed portions using etching techniques to facilitate conductor formation within high-aspect-ratio penetration channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the internal diameter of the penetration hole is reduced to achieve miniaturization, then the aspect ratio of the penetration hole is increased, but it becomes difficult to form the adhesive layer in the inner portion of the penetration hole
Solution Approach 1:
The patent changes the geometric parameters of the penetration hole by forming a tapered structure where the upper opening has a larger diameter than the lower opening. This parameter change allows the adhesive layer to be effectively formed in the wider upper portion while still achieving the desired miniaturization in the lower penetration region.
Solution Approach 2:
The patent introduces a dimensional variation along the depth of the penetration hole by creating a tapered shape. The hole transitions from a wider opening at the surface to a narrower opening at the bottom, adding a vertical dimension to the cross-sectional area variation and enabling adhesive layer formation in the wider upper region.
2Length of moving object
If the aspect ratio of the penetration hole is increased, then miniaturization is achieved, but the adhesive properties of the conductor and inner wall deteriorate
Solution Approach 1:
The patent modifies the geometric parameters of the penetration hole by creating a tapered structure. The upper opening has a larger diameter that provides sufficient surface area for adhesive layer formation, while the lower opening maintains the necessary aspect ratio for miniaturization. This parameter optimization balances adhesive properties with miniaturization requirements.
Solution Approach 2:
The patent applies local quality by having different cross-sectional areas at different locations along the penetration hole. The upper portion has a larger cross-sectional area to facilitate adhesive layer formation and conductor bonding, while the lower portion has a smaller cross-sectional area to achieve the desired aspect ratio and miniaturization.
3Ease of manufacture
If heat is applied due to subsequent manufacturing process, then processing is enabled, but the conductor sticks out or slips out from the penetration hole due to thermal expansion difference
Solution Approach 1:
The patent changes the geometric parameters of the penetration hole by forming a tapered structure where the upper opening is wider than the lower opening. This parameter change creates a mechanical constraint that prevents the conductor from sticking out or slipping out during thermal expansion, while still allowing necessary manufacturing heat treatment.
Solution Approach 2:
The tapered structure of the penetration hole provides beforehand cushioning by creating a mechanical interference fit that compensates for thermal expansion differences. The wider upper portion and narrower lower portion work together to constrain the conductor in place during and after heating processes.
4Reliability
If the cross-sectional area of connection wiring is made smaller, then conductor protrusion is suppressed, but manufacturing complexity increases
Solution Approach 1:
The patent changes the geometric parameters of the penetration wiring by creating a tapered structure where the cross-sectional area varies along the length. The connection wiring has a smaller cross-sectional area at the penetration hole interface to suppress protrusion, while the structure remains manufacturable through controlled tapering rather than abrupt changes.
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 design effectively suppresses conductor protrusion from the penetration hole even under heat or external forces, ensuring reliable electrical connection and stable conductor formation within high-aspect-ratio channels.
Implementation Method 1
a method that grows a conductor (a metal) inside a penetration hole, in which an adhesive layer (a seed layer), which improves adhesive properties with a conductor, is formed as a film, using an electrolytic plating technique
Implementation Method 2
using an electrolytic plating technique by forming the adhesive layer as a film inside the penetration hole using a sputtering technique
Implementation Method 3
a piezoelectric element (a kind of actuator) that brings about a pressure fluctuation in liquid inside the pressure chamber
Data Source
AI summary
A liquid ejecting head includes a first substrate in which a piezoelectric element is provided; and a second substrate on which the first substrate is connected to a first surface, in which the second substrate is provided with a penetration hole, which penetrates through the second substrate in a plate thickness direction, and penetration wiring, which is formed from a conductor that is formed in an inner portion of the penetration hole, the penetration wiring is formed from a first end portion, which is provided on a first surface side, a second end portion, which is provided on a second surface side, which is a surface that is on an opposite side to the first surface, and connection wiring, which connects the first end portion and the second end portion, and a cross-sectional area of the connection wiring in a planar direction of the first surface is smaller than cross-sectional areas of the first end portion and the second end portion in the planar direction.