Pre-stressed Bending Transducer for Micro Pump Compression
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Solution Overview
Problem
Conventional micro pumps face limitations in compression ratio due to large dead volumes and limited stroke volumes, primarily driven by piezoelectric principles, which complicate production and lead to inefficiencies in fluid handling, especially with gas bubbles.
Innovation Solution
A method for manufacturing a bending transducer with a pre-stressed membrane that adapts to the actuation signal, allowing the membrane to assume a pre-bulged shape during bonding, reducing dead volume and increasing compression ratio by applying a production signal similar to the operation signal, enabling efficient movement between bulged and less bulged positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If piezoelectric driving principle is used for micro pump, then the pump can be actuated, but the compression ratio is limited due to large dead volume and limited stroke volume
Solution Approach 1:
The membrane is pre-bulged during the bonding process before final assembly, so that when the pump operates, the membrane has reduced travel distance to cover, minimizing dead volume. This preliminary shaping action resolves the contradiction by preparing the membrane in its optimal configuration before operation begins.
Solution Approach 2:
The invention changes the physical state and shape parameters of the membrane during manufacturing. By applying voltage during bonding to create a pre-bulged shape, the membrane's geometric parameters are optimized before operation, enabling higher compression ratio while maintaining piezoelectric actuation.
2Reliability
If piezoelectric means is moved in one direction only, then the pump can operate, but it is difficult to reduce dead volume and increase compression ratio
Solution Approach 1:
The pump chamber and membrane are pre-shaped during manufacturing to account for the single-direction movement constraint. The membrane is pre-bulged and the chamber is pre-formed so that the limited unidirectional stroke achieves maximum compression ratio without requiring complex adaptive geometries.
Solution Approach 2:
By changing the geometric parameters of the membrane and pump chamber during manufacturing, the design compensates for unidirectional movement. The pre-bulged shape and chamber geometry are optimized so that the membrane's limited travel distance achieves the desired compression ratio.
3Reliability
If pump chamber contour is adapted to bend line of membrane, then dead volume is reduced, but production becomes complex and costly
Solution Approach 1:
The membrane is pre-bulged during bonding to achieve the optimal shape without requiring complex post-manufacturing adjustments. This preliminary shaping eliminates the need for complex pump chamber contours, simplifying manufacturing while maintaining high compression ratio.
Solution Approach 2:
Instead of adapting the pump chamber contour to match the membrane bend line (complex approach), the invention inverts the approach by pre-shaping the membrane itself during manufacturing. This simplifies the pump chamber design to a basic geometry while achieving the same dead volume reduction through membrane pre-forming.
4Manufacturing precision
If multiple etching steps are applied to wafer for alignment, then alignment can be achieved, but manufacturing effort increases significantly
Solution Approach 1:
Alignment features and membrane shapes are pre-defined during wafer fabrication before bonding. The pre-bulging process and electrode patterns are established in advance, eliminating the need for multiple post-bonding etching steps to achieve alignment, thus reducing manufacturing effort while maintaining precision.
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 approach enhances the compression ratio of micro pumps, reduces dead volume, and improves production engineering, making them more reliable and efficient for fluid handling, including bubble-tolerant operations.
Implementation Method 1
almost all of the micro membrane pumps available on the market are driven by piezoelectric driving principles
Implementation Method 2
applying a production signal to the drive element during the bonding of the drive element to the membrane such that the drive element is pre-stressed after the bonding
Data Source
AI summary
A method of manufacturing a bending transducer having a drive element and a membrane includes providing the membrane and the drive element and applying a production signal to the drive element during a bonding of the drive element to the membrane such that the drive element is pre-stressed after the bonding, wherein the production signal is of a same kind as an operation signal to operate the bending transducer.