MEMS Electrode Height Configuration for Quadrature Compensation

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Solution Overview

Problem

Existing microelectromechanical (MEMS) gyroscopes and acceleration sensors face challenges in quadrature compensation and drive force, which affect their sensitivity and reliability.

Innovation Solution

The use of electrodes located at different heights from the proof mass in MEMS devices improves quadrature compensation and drive force, thereby enhancing the reliability of MEMS gyroscopes and acceleration sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If electrodes are placed at the same height as the proof mass, then the structure is simple and easy to manufacture, but the quadrature compensation and drive force are insufficient

Engineering Contradiction:
Improvequadrature compensationVSAvoidelectrode structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces a vertical dimension (z-direction) to the electrode arrangement by positioning electrodes at different heights relative to the proof mass. Specifically, a first electrode is located at a first height in the z-direction and a second electrode is located at a second height, creating a three-dimensional configuration that enables improved quadrature compensation and drive force while maintaining manufacturing feasibility through established MEMS fabrication processes

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If electrodes are placed at different heights from the proof mass, then the quadrature compensation and drive force are improved, but the manufacturing complexity increases

Engineering Contradiction:
Improvesignal to noise ratioVSAvoidelectrode positioning
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The patent utilizes parameter changes in the vertical dimension by defining specific height relationships between electrodes and the proof mass. The first electrode is positioned at a first height and the second electrode at a second height, where these height parameters are optimized to improve signal-to-noise ratio and linearity. The patent provides guidance on relative positioning while acknowledging that absolute dimensions can be adjusted based on specific device requirements and fabrication capabilities

Inventive Principle:
Principle #35Parameter changes

3Reliability

If electrodes are placed at different heights from the proof mass, then the reliability of MEMS gyroscopes is improved, but the device complexity increases

Engineering Contradiction:
Improvegyroscope reliabilityVSAvoidelectrode arrangement
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the electrode system into distinct segments - a first electrode and a second electrode - positioned at different heights. This segmentation allows each electrode to serve specific functional purposes in the quadrature compensation and drive force generation, thereby improving gyroscope reliability. The segmented approach enables independent optimization of each electrode's position and function while maintaining overall system coherence

Inventive Principle:
Principle #1Segmentation

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 configuration enhances the signal-to-noise ratio and linearity in MEMS acceleration sensors and improves the reliability of MEMS gyroscopes by optimizing quadrature compensation and drive force.

Implementation Method 1

The electrodes are fabricated using MEMS microfabrication processes... the electrode which is attached to the capping element and the proof mass form a force transducer

Methodology Applied
Scientific EffectElectrostatic force: Electrostatics

Implementation Method 2

The transducer can be used to measure the movement of a proof mass or to drive the movement of a proof mass

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP4538639A1Electrodes in MEMS devices
Publication Date: 2025.04.16 MURATA MFG CO LTD
  • EP4538639A1 patent drawingFigure 1a~1b
  • EP4538639A1 patent drawingFigure 2a~2b
  • EP4538639A1 patent drawingFigure 3a~3b

AI summary

The disclosure describes microelectromechanical devices comprising a structure element (301) having at least one proof mass (302, 312) and a capping element (300, 310) having at least a first electrode (304 307, 313)) and a second electrode (305, 306, 314). Several embodiments are described wherein at least the first electrode and the second electrode are respectively located at different heights from the proof mass. The disclosed electrodes arrangements allow improvements in MEMS gyroscopes and accelerations sensors performance and reliability.