Piezo Composite Exciter Element for High Frequency MEMS Testing
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Solution Overview
Problem
Existing vibration exciters are limited in frequency range, unable to generate reliable mechanical movements above 100 kHz, and cannot produce controlled in-plane movements or rotations, which are essential for testing and calibrating microelectromechanical systems (MEMS) sensors and actuators.
Innovation Solution
A piezo composite exciter element with segmented contact surfaces and a counter-mass structure, allowing for separate activation of piezo elements to generate translational, rotational, and wave-like movements up to several megahertz, and enabling precise control of movements in both out-of-plane and in-plane directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a purely electrodynamic vibration exciter is used, then the device can generate vibrations up to 100 kHz, but it cannot generate clean translational vibrations and the upper frequency limit is restricted
Solution Approach 1:
The patent replaces the electrodynamic excitation system with a piezoelectric exciter that uses piezoelectric ceramics to generate mechanical vibrations. This substitution enables clean translational vibrations and extends the frequency range beyond 100 kHz by utilizing the piezoelectric effect rather than electromagnetic induction, fundamentally changing the excitation mechanism to achieve both high frequency and vibration quality
2Reliability
If a stack of piezo vibrating plates is used, then good translational movement is achieved, but vibration frequencies above 100 kHz cannot be generated and the upper limit is given as 40 kHz
Solution Approach 1:
The patent changes the operating parameters of the piezoelectric system by using rod-like piezo elements instead of plate structures, and by applying segmented voltages to different contact surfaces. This parameter change enables the exciter to operate at frequencies above 100 kHz while maintaining controlled translational movements, overcoming the frequency limitation of traditional piezo plate stacks
3Ease of operation
If traditional vibration exciters are used, then they can operate in their frequency range, but they cannot generate controlled in-plane movements or rotations
Solution Approach 1:
The patent divides the contact surfaces of the piezoelectric exciter into multiple segments that can be independently activated. By applying voltages to different segmented contact surfaces in combination, the system can generate not only out-of-plane vibrations but also controlled in-plane movements and rotations, thereby achieving multi-directional motion control while operating across a wide frequency range
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
Enables reliable generation of mechanical movements across a wide frequency range, including above 100 kHz, allowing for effective testing, characterization, and calibration of MEMS devices with controlled in-plane and rotational movements.
Implementation Method 1
A piezo oscillator 1, as is shown in FIG. 1, is used therein. The piezo oscillator 1 is arranged between the coupling member 0.4 and a counter-mass 0.5.
Data Source
AI summary
An exciter element for generating or measuring mechanical movements with an exciter and a receptacle for an object under test and with an electrical inter-face for transmitting the excitation or measurement data and a method for producing such an exciter element, performs reliable measurement or generation in the event of mechanical movements above 100 kHz up to a few megahertz and permits both “out-of-plane” and “in-plane” movements or rotations of the DUT. A flat piezo composite, which is known per se, with a first face lying transverse to the direction of the plate thickness, a second face spaced apart from the first face by the thickness of the plate and lying parallel to the first face, and with rod-shaped piezo elements extending between the first and second face, is used as an exciter.