Multichannel Acceleration Sensor with Predeflected Seismic Mass
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Solution Overview
Problem
Existing acceleration sensors cannot detect acceleration forces acting both parallel and perpendicular to the substrate using a single sensor element, and they require complex wiring and additional space for rocker structures.
Innovation Solution
A single sensor element with an excitation mechanism that predeflects the seismic mass perpendicular to the substrate, allowing it to detect both parallel and perpendicular deflections using a linear relationship between acceleration forces and electrical capacitance, reducing installation space and wiring complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a single sensor element is used to detect acceleration forces, then the installation space is reduced, but the ability to detect both parallel and perpendicular deflections is lost
Solution Approach 1:
The single sensor element is designed to perform multiple functions: detecting acceleration forces both parallel and perpendicular to the substrate. The seismic mass can be deflected in two independent directions, and the same detecting element (capacitive sensor) measures both types of deflection, eliminating the need for separate sensor elements for each direction.
Solution Approach 2:
The patent introduces a second degree of freedom by allowing the seismic mass to deflect not only parallel to the substrate (conventional acceleration sensing) but also perpendicular to the substrate. This is achieved through a compliant support structure that enables vertical deflection, transforming a single-plane sensor into a three-dimensional acceleration sensor.
2Adaptability or versatility
If a rocker structure is used to sense acceleration forces perpendicular to the substrate, then the detection capability is improved, but the installation space increases
Solution Approach 1:
The patent extracts the essential function of the rocker structure (enabling perpendicular deflection) and implements it through a simplified compliant support structure integrated directly into the substrate. This eliminates the need for a separate mechanical rocker assembly, reducing the installation space while maintaining the ability to sense perpendicular acceleration forces.
3Measurement precision
If the seismic mass is predeflected perpendicular to the substrate, then the linear relationship between acceleration force and detection signal is achieved, but the device complexity increases
Solution Approach 1:
The seismic mass is predeflected perpendicular to the substrate using an excitation element (electrostatic actuator) before the actual measurement begins. This predeflection positions the seismic mass at an optimal location where the capacitive detection element measures acceleration forces with a linear relationship, improving measurement precision while using a simple integrated actuator rather than complex mechanical positioning mechanisms.
4Measurement precision
If separate detecting elements are used for parallel and perpendicular deflections, then the measurement precision is improved, but the wiring complexity increases
Solution Approach 1:
The patent merges the detection function into a single capacitive sensing element that simultaneously measures both parallel and perpendicular deflections of the seismic mass. By using the same detecting element for both measurement directions, the patent significantly reduces wiring complexity and signal processing requirements compared to using separate detecting elements for each axis.
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 efficient detection of acceleration forces in two independent directions with reduced installation space and simplified evaluation, using a single detecting element for both deflections, and allows for precise measurement of acceleration force intensity and direction.
Implementation Method 1
the excitation element is permanently connected to the substrate and/or includes a surface electrode so that an electrostatic excitation of the seismic mass relative to the substrate and perpendicular to the main extension plane is implemented by applying an electrical potential difference between the surface electrode and the seismic mass
Implementation Method 2
which includes, in particular, a change in electrical capacitance
Data Source
AI summary
A sensor element, in particular a multichannel acceleration sensor having a substrate and a seismic mass, the sensor element having a detecting element for detecting a deflection of the seismic mass relative to the substrate, and the sensor element having an excitation element for exciting a deflection of the seismic mass perpendicular to the main extension plane.