MEMS Inertial Sensor Z-Coupling for Interference Suppression
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Solution Overview
Problem
Conventional inertial sensors are sensitive to interference signals, particularly parallel to the main plane of extension, and lack flexibility in detecting both rotation and acceleration both parallel and perpendicular to this plane, with masses that are often too inert, leading to sensitivity to substrate bending.
Innovation Solution
A microelectromechanical system (MEMS) inertial sensor with a simple design, featuring a Z-shaped or rhombus-shaped coupling structure and central substrate connection point, utilizing spring structures and varying coupling element lengths to suppress interference modes and reduce mass inertia, allowing for robust detection of rotation and acceleration in multiple directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional inertial sensors use multiple movable masses mechanically coupled to the substrate, then the sensor can detect acceleration and rotation, but the sensor becomes sensitive to interference signals and substrate bending
Solution Approach 1:
The sensor uses exactly two movable masses instead of multiple masses, segmenting the measurement function between these two masses. Each mass is coupled to the substrate via exactly one substrate connection point, creating independent measurement paths that reduce interference coupling between multiple masses while maintaining the ability to detect both acceleration and rotation through their coordinated movement.
Solution Approach 2:
The patent extracts and eliminates the substrate connection points from the coupling structure, leaving only one substrate connection point per mass. This removal of redundant connection points directly reduces the sensor's sensitivity to substrate bending and interference signals, as the masses are no longer mechanically coupled to multiple points on the substrate that could transmit interference.
2Stability of the object's composition
If the sensor uses multiple substrate connection points for coupling masses, then the structure is more stable, but the sensor becomes sensitive to substrate bending
Solution Approach 1:
The patent removes redundant substrate connection points, leaving exactly one substrate connection point per movable mass. This extraction of unnecessary connection points eliminates the mechanical pathways through which substrate bending could couple to the masses, thereby reducing sensitivity to substrate deformation while maintaining structural stability through the optimized single-point coupling configuration.
3Measurement precision
If the sensor uses larger masses for detection, then the signal strength increases, but the sensor becomes more sensitive to interference signals
Solution Approach 1:
The patent optimizes the local quality of the masses by using exactly two masses with specific inertial properties rather than multiple larger masses. The single substrate connection point per mass creates a localized coupling that maintains sufficient signal strength from the mass movement while minimizing the overall inertial mass that would be sensitive to interference signals, achieving an optimal local mass configuration.
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 sensor effectively suppresses interference signals and is insensitive to substrate bending, enabling flexible detection of both rotation and acceleration parallel and perpendicular to the main plane of extension with reduced mass inertia, resulting in improved signal quality and robustness.
Implementation Method 1
The coupling takes place particularly preferably via spring structures
Data Source
AI summary
A microelectromechanical inertial sensor to measure a rate of rotation and/or acceleration, the inertial sensor having a substrate, at least two deflectable masses coupled mechanically to the substrate, and at least one detector detecting movements of the masses along a first direction, the masses being mechanically coupled to one another by at least one first, second, and third coupling element, the coupling elements being configured so that when there is a deflection of the masses from the rest position a pivoting of a first main direction of extension of the first coupling element relative to a second main direction of extension of the second coupling element takes place and a pivoting of the second main direction of extension relative to the third main direction of extension of the third coupling element takes place, and the coupling elements being coupled mechanically to the substrate via at least one substrate connecting point.