MEMS Gyro Sensor Electrode Design for Stability

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Solution Overview

Problem

Existing MEMS-based gyro sensors for angular velocity detection are prone to operational variations due to processing inconsistencies, affecting their normal operation.

Innovation Solution

An angular velocity acquisition device is designed with a movable body that vibrates in response to Coriolis force, featuring a movable electrode portion, a hold electrode, and stoppers to maintain precise positioning and reduce power consumption, utilizing a comb-teeth pattern and alternating electrostatic forces to detect changes in capacitance for angular velocity calculation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If MEMS technology is used to manufacture gyro sensors, then miniaturization and integration are achieved, but processing variations occur that impair normal operation

Engineering Contradiction:

Improvesensor sizeVSAvoidoperational stability

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The patent changes the geometric parameters of the electrostatic components, specifically designing the hold electrode with a comb-teeth pattern where the electrode width is set to 0.5-2.0 times the gap width. This parameter optimization ensures stable capacitance characteristics despite processing variations, resolving the contradiction between miniaturization and operational reliability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The stopper structure is designed in advance to prevent short circuits before they can occur during operation. By positioning the stopper at a predetermined distance from the electrode, the design proactively compensates for processing variations that might otherwise cause short circuits, maintaining reliability in miniaturized structures

Inventive Principle:

Principle #10Preliminary action

2Measurement precision

If the movable body is held at a fixed position using electrostatic force, then positioning precision is improved, but power consumption increases

Engineering Contradiction:

Improvepositioning accuracyVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The hold electrode applies electrostatic force periodically rather than continuously. The comb-teeth pattern allows the electrode to engage with the movable body only when needed for positioning, reducing power consumption while maintaining positioning accuracy through periodic stabilization rather than continuous force application

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The hold electrode applies electrostatic force only to the extent necessary for positioning - the comb-teeth pattern provides just enough holding force to maintain position without excessive force that would increase power consumption. The force is applied partially, only when positioning is required, rather than continuously

Inventive Principle:

Principle #16Partial or excessive action

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 device achieves stable operation with low power consumption by minimizing the impact of processing variations and preventing short circuits, enabling accurate detection of angular velocity with reduced power usage.

Implementation Method 1

a movable body that vibrates in a first direction and in a second direction based on Coriolis force

Methodology Applied

Scientific EffectCoriolis force: Coriolis Force

Implementation Method 2

a hold electrode that extends in the second direction and includes a fixed electrode portion opposite to the movable electrode portion across a gap

Methodology Applied

Scientific EffectElectrostatic force: Electrostatics

Implementation Method 3

utilizing a comb-teeth pattern and alternating electrostatic forces to detect changes in capacitance for angular velocity calculation

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS10330472B2Angular velocity acquisition device

Publication Date: 2019.06.25 KK TOSHIBA

AI summary

According to one embodiment, an angular velocity acquisition device includes a movable body that vibrates in a first direction and in a second direction that is based on Coriolis force and includes a movable electrode portion extending in the second direction, a hold electrode that extends in the second direction and includes a fixed electrode portion opposite to the movable electrode portion across a gap, and a stopper that is provided between the fixed electrode portion and the movable electrode portion and includes an end portion closer to the movable electrode portion than a surface of the fixed electrode portion facing the movable electrode portion.