MEMS Spurious Mode Suppression Using Electromagnetic Frequency Tuning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Oscillatory micromechanical structures in rotation rate sensors and micromirrors often experience undesirable parasitic spurious modes due to manufacturing tolerances, leading to interference in detection signals and potential mechanical damage from excited spurious oscillations.
Innovation Solution
An adjusting device applying electromagnetic interactions, such as electrostatic or electrodynamic fields, is integrated to counteract parasitic spurious modes by adjusting the resonant frequency of system components, preventing excitation of these modes through controlled DC or AC voltage applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If parasitic spurious modes are prevented from being placed precisely at integer multiples of drive frequencies through configuration measures, then manufacturing precision requirements increase, but parasitic spurious modes still occur due to manufacturing tolerances
Solution Approach 1:
The patent applies preliminary action by pre-configuring damping elements (dashpot elements) into the oscillatory micromechanical structure during manufacturing. These elements are positioned to provide targeted damping of specific spurious modes before the device operates, preventing the harmful effects of parasitic oscillations without requiring extremely tight manufacturing tolerances on frequency placement.
Solution Approach 2:
The patent changes the damping parameter of the system by introducing adjustable damping elements that can modify the damping characteristics of specific modes. By changing the damping parameter rather than relying solely on precise frequency configuration, the system can suppress spurious modes even when manufacturing tolerances cause frequency variations.
2Reliability
If configuration measures are made to avoid internal resonances, then device complexity increases, but parasitic spurious modes still occur due to manufacturing tolerances
Solution Approach 1:
The patent applies self-service by designing the oscillatory micromechanical structure to automatically dampen spurious modes through integrated dashpot elements. The structure serves itself by incorporating passive damping mechanisms that automatically suppress parasitic oscillations without requiring external control systems or complex active compensation circuits, thereby reducing overall device complexity while improving reliability.
3Productivity
If oscillatory micromechanical structures are used for intended functions, then useful modes are utilized, but parasitic spurious modes cause interference and potential mechanical damage
Solution Approach 1:
The patent applies local quality by introducing damping elements with specific characteristics at particular locations within the oscillatory structure. The dashpot elements are strategically positioned to provide localized damping exactly where spurious modes manifest, allowing the useful modes to continue their intended function while selectively suppressing harmful parasitic oscillations in specific regions of the device.
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 effectively reduces the influence of parasitic spurious modes, preventing interference and mechanical damage by ensuring the resonant frequency is not at integer multiples of drive frequencies, thereby enhancing the accuracy and reliability of the systems.
Implementation Method 1
The adjusting device 50 applies an electromagnetic interaction W to the system component 1, in particular an electrostatic or electrodynamic interaction
Implementation Method 2
The adjusting device 50 applies an electromagnetic interaction W to the system component 1, in particular an electrostatic or electrodynamic interaction
Implementation Method 3
The rotation rate sensors use, for example, drive modes to set detection structures into resonant oscillations
Implementation Method 4
These structures in turn detect rotation rates via the measurement of the occurring Coriolis accelerations
Implementation Method 5
The drive of the oscillatory micromechanical structures is carried out electrostatically or piezoelectrically
Implementation Method 6
The drive of the oscillatory micromechanical structures is carried out electrostatically or piezoelectrically
Data Source
AI summary
A MEMS device and a corresponding operating method. The MEMS device is equipped with an oscillatory micromechanical system, which is excitable in a plurality of useful modes, the oscillatory micromechanical system including at least one system component, which is excitable in at least one parasitic spurious mode by a superposition of the useful modes. An adjusting device is provided, which is configured in such a way that it counteracts the parasitic spurious mode by application of an electromagnetic interaction to the system component.