Angular Velocity Sensor With Asymmetric Groove Depths

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Solution Overview

Problem

Existing angular velocity detection technologies face limitations in increasing detection sensitivity due to equal groove depths in detection and drive vibration arms, making it difficult to enhance sensitivity beyond a certain depth.

Innovation Solution

The angular velocity detection element features drive and detection vibration arms with asymmetric groove depths, where d2/t2 > d1/t1, allowing for deeper grooves in detection arms relative to drive arms, thereby enhancing detection sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the groove depth of detection vibration arms is increased to improve detection sensitivity, then detection sensitivity improves, but when groove depth equals drive vibration arm groove depth, further improvement becomes difficult

Engineering Contradiction:
Improvedetection sensitivityVSAvoidgroove depth configuration
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies asymmetry by setting different groove depths for detection vibration arms and drive vibration arms. Specifically, the groove depth of detection vibration arms is designed to be greater than that of drive vibration arms, creating an asymmetric configuration that optimizes detection sensitivity while maintaining drive performance. This asymmetric design resolves the technical contradiction by allowing the detection arms to have deeper grooves for higher sensitivity without requiring the drive arms to have equally deep grooves.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent applies local quality by optimizing groove depth specifically for the detection vibration arms rather than uniformly across all vibration arms. The detection vibration arms are given deeper grooves localized to their structure, while drive vibration arms maintain shallower grooves. This localized optimization allows enhanced detection sensitivity in the detection arms without compromising the mechanical strength and drive efficiency of the drive arms.

Inventive Principle:
Principle #3Local quality

2Measurement precision

If groove depth is increased to enhance detection sensitivity, then detection sensitivity improves, but mechanical strength may be compromised

Engineering Contradiction:
Improvedetection sensitivityVSAvoidmechanical strength
Core Design Contradiction:
Measurement precisionVSStrength

Solution Approach 1:

The asymmetric groove depth configuration allows detection vibration arms to have deeper grooves for enhanced sensitivity while drive vibration arms maintain shallower grooves that preserve mechanical strength. The detection arms can be optimized for sensitivity without compromising overall structural integrity, as the drive arms provide the necessary mechanical support with their shallower grooves.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent applies local quality by providing deeper grooves only where needed for detection sensitivity in the detection vibration arms, while maintaining sufficient material thickness and mechanical strength in the drive vibration arms. This localized groove depth optimization ensures that sensitivity enhancement does not come at the cost of overall mechanical strength.

Inventive Principle:
Principle #3Local quality

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 significantly increases detection sensitivity beyond previous limits, improving angular velocity detection accuracy and reducing thermoelastic loss while maintaining mechanical strength.

Implementation Method 1

a drive vibration arm configured to perform flexural vibration according to an applied drive signal

Methodology Applied
Scientific EffectFlexural vibration: Vibration

Implementation Method 2

a detection vibration arm configured to perform flexural vibration according to an applied angular velocity

Methodology Applied
Scientific EffectFlexural vibration: Vibration

Implementation Method 3

detection vibration arm configured to perform flexural vibration according to an applied angular velocity

Methodology Applied
Scientific EffectCoriolis effect: Coriolis Force

Data Source

PatentEP4361559B1Angular velocity detection element and angular velocity sensor
Publication Date: 2025.10.01 SEIKO EPSON CORP
  • EP4361559B1 patent drawingFigure 1
  • EP4361559B1 patent drawingFigure 2~3
  • EP4361559B1 patent drawingFigure 4~5

AI summary

An angular velocity detection element includes: a drive vibration arm configured to perform flexural vibration according to an applied drive signal; and a detection vibration arm configured to perform flexural vibration according to an applied angular velocity. Each of the drive vibration arm and the detection vibration arm has a bottomed groove portion along an extending direction. d2/t2 > d1/t1, in which t1 is a thickness of the drive vibration arm, d1 is a depth of the groove portion of the drive vibration arm, t2 is a thickness of the detection vibration arm, and d2 is a depth of the groove portion of the detection vibration arm.