Resonator Element Base Geometry for High Q-Value Miniaturization

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Solution Overview

Problem

Conventional resonator elements face challenges in achieving a high Q-value while minimizing size, as reducing the base portion's dimensions leads to increased thermoelastic loss and vibration leakage, affecting the stability and frequency accuracy of oscillation circuits in small electronic devices.

Innovation Solution

The resonator element design includes a base portion with specific dimensions and a supporting arm configuration that optimizes the ratio of the shortest distance between end surfaces (Wb/We) to reduce thermoelastic loss and vibration leakage, allowing for a high Q-value and smaller size, with the supporting arm protruding between vibrating arms to enhance stability and frequency reproducibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the dimensions of the base portion are reduced to minimize size, then the overall size of the resonator element is reduced, but the Q-value is significantly reduced due to increased thermoelastic loss

Engineering Contradiction:

Improvesize of resonator elementVSAvoidthermoelastic loss

Core Design Contradiction:

Volume of moving objectVSLoss of energy

Solution Approach 1:

The invention optimizes the base width Wb to satisfy the relationship 0.81≤Wb/We≤1.70, where We is the effective width of the vibrating arms. By controlling this geometric parameter within a specific range, the invention reduces thermoelastic loss while maintaining miniaturization, thereby resolving the contradiction between size reduction and energy loss.

Inventive Principle:

Principle #35Parameter changes

2Volume of moving object

If the dimensions of the base portion are reduced to minimize size, then the overall size of the resonator element is reduced, but the stability and frequency accuracy of oscillation circuits are degraded

Engineering Contradiction:

Improvesize of resonator elementVSAvoidstability and frequency accuracy

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

By optimizing the base width Wb to satisfy 0.81≤Wb/We≤1.70, the invention maintains high Q-value which directly improves the stability and frequency accuracy of oscillation circuits while achieving miniaturization.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention introduces a supporting arm extending in the thickness direction of the base portion, utilizing the third dimension (Z-axis) to provide structural support and reduce vibration leakage without increasing the planar footprint, thus maintaining small size while improving reliability.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Loss of energy

If a supporting arm is added between vibrating arms to reduce vibration leakage, then the Q-value is improved, but the device complexity increases

Engineering Contradiction:

Improvevibration leakageVSAvoidstructural complexity

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The supporting arm serves multiple functions simultaneously: it provides mechanical support, reduces vibration leakage to improve Q-value, and maintains compact dimensions. This multi-functionality allows the invention to improve performance without proportionally increasing complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The supporting arm extends in the thickness direction (Z-axis) of the base portion, utilizing the vertical dimension to provide structural support without increasing the planar dimensions. This dimensional approach adds functionality while maintaining compact overall size.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 enables a resonator element with a high Q-value and reduced size, providing stable oscillation characteristics and improved frequency accuracy, suitable for small electronic devices and moving objects.

Implementation Method 1

reduce thermoelastic loss caused by a reduction in the distance between the first end surface and the second end surface of the base portion

Methodology Applied

Scientific EffectThermoelastic loss:

Implementation Method 2

reduce vibration leakage caused by the bending vibration of the vibrating arm

Methodology Applied

Scientific EffectVibration leakage:

Data Source

PatentUS10659006B2Resonator element, resonator, electronic device, electronic apparatus, and moving object

Publication Date: 2020.05.19 SEIKO EPSON CORP

AI summary

A resonator element includes: a base portion including a first end surface that faces a first direction and a second end surface that faces a direction opposite to the first direction, a first vibrating arm that is provided integrally with the base portion and is connected to the first end surface; and a second vibrating arm that is provided integrally with the base portion along the first vibrating arm and is connected to the first end surface. When the shortest distance between the first end surface and the second end surface is Wb and an effective width between the shortest distance Wb and the base portion is We, 0.81≤Wb/We≤1.70 is satisfied.