Circular MEMS Pump Actuation for Even Fluid Flow
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Solution Overview
Problem
Micro-electromechanical systems (MEMS) pumps face inefficiencies due to uneven actuation displacement, which reduces transmission efficiency and stability, particularly because the distance between the piezoelectric sheet and actuation portion are not equal, leading to maximum displacement at the corners rather than the center, affecting fluid transport capacity.
Innovation Solution
A MEMS pump design featuring a first substrate with conical inlets, a second substrate with a silicon wafer layer and oxide layers, and a piezoelectric element, where the actuation portion is circular with a maximum stress value, and the piezoelectric element is circular with a piezoelectric stress value, optimizing the stress distribution and fluid channel layout to enhance even actuation and fluid flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a square-shaped piezoelectric sheet and actuation portion are used, then the device structure is simple to manufacture, but the actuation force is distributed unevenly causing maximum displacement at corners rather than center, reducing transmission efficiency
Solution Approach 1:
The patent changes the shape of the piezoelectric sheet and actuation portion from square to circular. This asymmetric change in geometry ensures that the actuation force is distributed evenly across the surface, with the maximum displacement occurring at the center rather than at corners. The circular shape eliminates the corner regions that cause uneven force distribution in square designs, thereby improving transmission efficiency while remaining manufacturable through standard semiconductor processes.
2Ease of manufacture
If the distance between piezoelectric sheet and actuation portion is non-uniform, then the device structure is easier to fabricate, but the actuation becomes uneven reducing operational stability
Solution Approach 1:
The patent employs circular geometry for both the piezoelectric sheet and actuation portion, ensuring uniform radial distance from the center to all edges. This symmetric circular design creates even spacing between the piezoelectric sheet and actuation portion throughout, eliminating the non-uniform distance problems associated with square designs. The uniform spacing ensures consistent actuation force distribution, improving operational stability and reliability.
3Productivity
If higher actuation stress is applied to increase fluid transport capacity, then the pump efficiency increases, but the device lifespan decreases due to potential damage
Solution Approach 1:
The patent optimizes the circular dimensions and material properties to achieve an optimal stress distribution pattern. By changing the geometric parameters (circular radius, thickness) and material parameters of the piezoelectric sheet and actuation portion, the system achieves high fluid transport capacity through efficient center-directed actuation while distributing stress uniformly to prevent localized damage. This parameter optimization allows the device to operate at high efficiency levels without compromising structural integrity or lifespan.
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 design improves fluid transmission efficiency and maintains structural stability by ensuring even force distribution across the actuation portion, balancing actuation stress and frequency to prevent damage while maintaining high efficiency and extending the device's lifespan.
Implementation Method 1
through applying an AC voltage to the piezoelectric sheet 1b, the piezoelectric sheet 1b is deformed correspondingly to the voltage value and the frequency of the AC voltage due to the inverse piezoelectric effect
Data Source
AI summary
A micro-electromechanical systems pump includes a first substrate, a first oxide layer, a second substrate, and a piezoelectric element. The first oxide layer is stacked on the first substrate. The second substrate is combined with the first substrate, and the second substrate includes a silicon wafer layer, a second oxide layer, and a silicon material layer. The silicon wafer layer has an actuation portion. The actuation portion is circular and has a maximum stress value and an actuation stress value. The second oxide layer is formed on the silicon wafer layer. The silicon material layer is located at the second oxide layer and is combined with the first oxide layer. The piezoelectric element is stacked on the actuation portion, and has a piezoelectric stress value. The maximum stress value is greater than the actuation stress value, and the actuation stress value is greater than the piezoelectric stress value.