Piezoelectric Laminate Reinforcement for Inkjet Head
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Solution Overview
Problem
The thin piezoelectric layers in liquid ejecting heads, such as ink jet recording heads, are prone to cracking or chipping during handling due to reduced rigidity, leading to yield reduction and manufacturing challenges.
Innovation Solution
A method involving a laminate structure with a reinforcing member, a first electrode, a piezoelectric layer, and a second electrode, where the reinforcing member enhances rigidity by being partially removed to form a through hole for electrical connection, and the laminate is bonded to a flow path substrate with a vibration plate to reduce breakage and warpage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the piezoelectric layer is made thinner to reduce size and enable higher density placement, then the device can achieve higher integration and smaller dimensions, but the piezoelectric layer becomes more prone to cracking and chipping during handling
Solution Approach 1:
The patent applies composite materials by creating a laminate structure that combines the piezoelectric layer with electrode layers and a reinforcing member. This composite structure provides mechanical support to the thin piezoelectric layer, preventing cracking and chipping during handling while maintaining the desired thin profile for high-density placement.
Solution Approach 2:
The patent segments the piezoelectric actuator into distinct functional layers: the piezoelectric layer for actuation, electrode layers for electrical connection, and a reinforcing member for mechanical support. This segmentation allows each layer to be optimized for its specific function while working together as an integrated unit that protects the thin piezoelectric layer.
2Reliability
If the piezoelectric layer is made thinner to improve handling properties and reduce breakage, then the device achieves better reliability, but the rigidity of the piezoelectric layer itself is reduced making it more susceptible to deformation
Solution Approach 1:
The laminate structure combines materials with different mechanical properties: the piezoelectric layer provides actuation function, while the reinforcing member (typically a ceramic or metal layer) provides the necessary rigidity and mechanical strength. This composite approach allows the thin piezoelectric layer to maintain reliability without sacrificing overall structural stability.
Solution Approach 2:
The reinforcing member is strategically positioned and dimensioned to provide localized mechanical support where needed, particularly at the edges and corners of the piezoelectric layer where stress concentration occurs. This local reinforcement approach maintains the thin profile in active areas while providing enhanced rigidity where structural support is required.
3Strength
If a laminate structure with reinforcing member is used to enhance rigidity and reduce breakage, then handling properties improve, but the device complexity increases due to additional layers and manufacturing steps
Solution Approach 1:
The patent merges multiple functions into the laminate structure: the electrode layers serve both electrical connection and partial mechanical support functions, while the reinforcing member provides both structural rigidity and, in some embodiments, electrical connection pathways. This merging reduces the need for separate components and simplifies the overall device architecture despite the multi-layer construction.
Solution Approach 2:
The reinforcing member is designed to serve multiple functions: providing mechanical strength and rigidity to the thin piezoelectric layer, serving as a structural support during assembly and handling, and in many embodiments, providing electrical connection pathways to external circuits. This multi-functionality reduces the need for additional separate components.
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 enhanced rigidity of the laminate structure reduces the likelihood of cracking and chipping during handling and allows for thinner piezoelectric layers, improving handling properties and enabling higher density placement of active components.
Implementation Method 1
a piezoelectric actuator that is fixed to one surface of the flow path forming substrate and that changes the pressure in the pressure generating chamber
Data Source
AI summary
A method for manufacturing a liquid ejecting head including a laminate formed of a flow path substrate having a flow path communicating with nozzle openings that eject a liquid, a first electrode, a piezoelectric layer, and a second electrode, the method including stacking the first electrode, the piezoelectric material, the second electrode, and a reinforcing member on top of one another to form a laminate; heating the laminate to form a piezoelectric layer made of the piezoelectric material; bonding the laminate to the flow path substrate on a first electrode side; and removing the reinforcing member.