Piezoelectric Inkjet Head Groove Layout for Misalignment Tolerance
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Solution Overview
Problem
Existing inkjet heads face reduced driven displacement of piezoelectric elements due to positional deviations between pressure chambers and surface electrodes, leading to suboptimal performance.
Innovation Solution
The design incorporates a first groove around the surface electrode that extends to match the outer shape of the pressure chamber, ensuring the groove is positioned more closely with the pressure chamber edges, maintaining or enhancing driven displacement even with positional deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a groove is formed around the surface electrode to reduce crosstalk, then crosstalk between piezoelectric elements is reduced, but the driven displacement of the piezoelectric element decreases due to positional deviations between the groove and pressure chamber
Solution Approach 1:
The groove is designed with non-uniform width where the width at the pressure chamber side is larger than the width at the electrode side. This local variation in groove geometry allows the groove to maintain closer proximity to the pressure chamber edge in critical regions, preserving driven displacement while still providing effective crosstalk reduction between adjacent piezoelectric elements.
Solution Approach 2:
The groove dimensions are optimized by changing the width parameter along its length. Specifically, the groove width is increased at the pressure chamber end and decreased at the electrode end, creating a tapered profile that balances two competing requirements: maintaining driven displacement through closer spacing to the pressure chamber while providing sufficient separation for crosstalk reduction.
2Object-affected harmful factors
If the groove is positioned closer to the surface electrode to reduce crosstalk, then crosstalk is reduced, but the alignment tolerance becomes more critical and performance degrades with positional deviations
Solution Approach 1:
The groove exhibits varying width along its length, being wider at the pressure chamber side and narrower at the electrode side. This local quality variation creates a design that is more tolerant to positional deviations, as the wider section at the pressure chamber side maintains effective coupling even when misalignment occurs, while the narrower section at the electrode side provides sufficient isolation for crosstalk reduction.
Solution Approach 2:
The asymmetric groove design anticipates potential positional deviations by built-in geometric compensation. The wider portion at the pressure chamber side acts as a cushion that maintains functional performance even when alignment is not perfect, thereby compensating for manufacturing tolerances and assembly variations before they can degrade performance.
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 maintains or increases the driven displacement of the piezoelectric element, ensuring consistent performance despite potential misalignments, thereby improving the reliability and efficiency of liquid droplet ejection.
Implementation Method 1
The piezoelectric element deforms the pressure chamber by being deformed upon application of voltage
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
A liquid droplet ejection head according to the present disclosure includes a nozzle, a pressure chamber, and a piezoelectric element. The nozzle ejects liquid droplets. The pressure chamber connects to the nozzle. The piezoelectric element deforms the pressure chamber by being deformed upon application of voltage. The piezoelectric element includes a surface electrode and a first groove. The surface electrode faces the pressure chamber. The first groove is positioned around the surface electrode and extends in a shape corresponding to an outer shape of the surface electrode. Where in plane perspective, a maximum distance and a minimum distance between an outer edge of the pressure chamber and an outer edge of the first groove are defined as A1 and A2, respectively, and in plan view, a maximum distance and a minimum distance between an outer edge of the surface electrode and the outer edge of the first groove are defined as B1 and B2, respectively, the following Equation (1) is satisfied: A1−A2<B1−B2