MEMS Piezoelectric Actuator Lifting Structure for High Force Deflection
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Solution Overview
Problem
Conventional MEMS loudspeakers face challenges in achieving high forces and deflections simultaneously due to the conflicting requirements of low spring stiffness for large deflections and high spring stiffness for force transmission, leading to inefficiencies and acoustic distortions.
Innovation Solution
A MEMS system with a membrane and a lifting structure connected to at least two piezoelectric actuators via spaced-apart connecting elements, allowing for simultaneous transmission of high forces and deflections while maintaining uniform and reproducible movement, preventing tipping modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If low spring stiffness is used to achieve large deflections, then deflection capability is improved, but force transmission capability deteriorates
Solution Approach 1:
The lifting structure is divided into multiple segments connected by connecting elements, allowing the system to achieve both large deflections through sequential segment movement and high force transmission through the distributed structure. Each segment can move independently while contributing to the overall lifting capability.
Solution Approach 2:
The patent transitions from a single-degree-of-freedom system to a multi-degree-of-freedom system by introducing multiple connecting elements that can move in different directions and planes. This dimensional expansion allows the structure to achieve large deflections while maintaining force transmission capability through geometric configuration.
2Force
If high spring stiffness is used to transmit high forces, then force transmission capability is improved, but deflection capability deteriorates
Solution Approach 1:
By segmenting the lifting structure into multiple rigid connected by flexible elements, the system can transmit high forces through the rigid segments while achieving large deflections through the coordinated movement of multiple segments. The segmentation allows force distribution across multiple connection points.
Solution Approach 2:
Different parts of the structure have different stiffness properties - the lifting structure segments are made rigid for force transmission, while the connecting elements are made flexible for deflection. This local differentiation of mechanical properties resolves the contradiction between force transmission and deflection capability.
3Reliability
If piezoelectric actuators are directly connected to the diaphragm, then actuator-diaphragm coupling is improved, but drive properties and diaphragm properties become coupled causing limitations
Solution Approach 1:
The patent introduces a lifting structure as an intermediary between the piezoelectric actuators and the diaphragm. This mediator allows the actuators to generate force and displacement independently while still effectively driving the diaphragm. The lifting structure decouples the drive properties from the diaphragm properties, enabling independent optimization of each component.
4Force
If electrodynamic drives are used to generate high forces and strokes, then force and displacement capability is improved, but power consumption increases due to low efficiency
Solution Approach 1:
The patent replaces electrodynamic drives with piezoelectric actuators, substituting a mechanical/electrical system with a direct electrical-to-mechanical conversion system. Piezoelectric materials convert electrical energy directly to mechanical displacement without the losses associated with electromagnetic conversion, achieving high force and stroke with lower power consumption.
5Object-affected harmful factors
If electrodynamic loudspeakers are used, then sufficient sound pressure is achieved, but acoustic distortion increases
Solution Approach 1:
The patent replaces electrodynamic drive mechanisms with piezoelectric actuators that directly convert electrical signals to mechanical motion. This substitution eliminates the electromagnetic nonlinearities that cause acoustic distortion in electrodynamic speakers, while maintaining the ability to generate sufficient sound pressure through the lifting structure mechanism.
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 solution enables efficient sound wave generation in the audible wavelength spectrum with improved force and displacement capabilities, reducing power consumption and acoustic distortions compared to conventional electrodynamic loudspeakers.
Implementation Method 1
at least two piezoelectric actuators (106_1 to 106_n) connected via a plurality of spaced-apart connecting elements (108_1 to 108_m) to a plurality of spaced-apart contact points (1101 to 110_m) of the lifting structure (104), wherein the at least two piezoelectric actuators (1061 to 106_n) are configured to cause a lifting movement of the lifting structure (104)
Data Source
Figure 1A
Figure 1B
Figure 2A~2B
AI summary
The invention relates to a MEMS, comprising a membrane, a reciprocating structure, which is coupled to the membrane, and at least two piezoelectric actuators, which are connected, by means of a plurality of connecting elements spaced apart from each other, to a plurality of contact points of the reciprocating structure spaced apart from each other, wherein the at least two piezoelectric actuators are designed to cause a reciprocating motion of the reciprocating structure in order to deflect the membrane.