Quartz Vibrator Support Structure for Thermal Stress Stability

Solution Overview

Problem

Quartz crystal vibrators experience hysteresis and frequency changes due to thermal distortion caused by differences in thermal expansion coefficients between the quartz crystal and its supporting components, leading to unstable vibration characteristics.

Innovation Solution

A vibrator device design with a supporting member and substrate configuration, where the area of the attaching portion is smaller than the fixed portion, and made of the same material as the vibration element, to minimize thermal stress-induced distortion and maintain mechanical strength, thereby reducing frequency changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the quartz crystal vibrator is supported by a conductive adhesive or supporting portion made of different material, then the mechanical strength and attachment are ensured, but thermal distortion occurs due to difference in thermal expansion coefficient causing hysteresis in frequency

Engineering Contradiction:

Improveattachment strengthVSAvoidfrequency stability

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The supporting member is made of the same material as the quartz crystal vibrator element, ensuring homogeneous thermal expansion characteristics. This eliminates the hysteresis phenomenon caused by differential thermal expansion between dissimilar materials while maintaining adequate mechanical attachment strength.

Inventive Principle:

Principle #33Homogeneity

Solution Approach 2:

The invention changes the material parameter of the supporting member to match the quartz crystal vibrator element, thereby changing the thermal expansion coefficient parameter to be identical. This parameter alignment resolves the thermal distortion issue while the geometric design (area ratio A1≥A2) maintains attachment strength.

Inventive Principle:

Principle #35Parameter changes

2Strength

If the area of attaching portion is made larger to improve attachment strength, then mechanical strength increases, but thermal stress-induced distortion increases causing greater frequency changes

Engineering Contradiction:

Improveattachment strengthVSAvoidfrequency precision

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

The invention applies local quality by creating a non-uniform area distribution: the fixed portion has a larger area (A1) to provide stable support and reduce thermal stress, while the attaching portion has a smaller area (A2) to maintain adequate attachment strength. This localized area optimization resolves the contradiction between strength and precision.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention introduces asymmetry in the area relationship between the fixed portion and attaching portion, with A1≥A2. This asymmetric design optimizes the balance between mechanical attachment strength and thermal stress-induced distortion, preventing frequency precision degradation while maintaining adequate attachment strength.

Inventive Principle:

Principle #4Asymmetry

3Reliability

If the area of fixed portion is made smaller to reduce thermal distortion, then frequency stability improves, but attachment strength may be compromised

Engineering Contradiction:

Improvefrequency stabilityVSAvoidattachment strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The invention applies local quality by creating a non-uniform area distribution: the fixed portion has a larger area (A1) to provide stable support and reduce thermal stress, while the attaching portion has a smaller area (A2) to maintain adequate attachment strength. This localized area optimization resolves the contradiction between strength and precision.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention introduces asymmetry in the area relationship between the fixed portion and attaching portion, with A1≥A2. This asymmetric design optimizes the balance between mechanical attachment strength and thermal stress-induced distortion, preventing frequency precision degradation while maintaining adequate attachment strength.

Inventive Principle:

Principle #4Asymmetry

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 design effectively alleviates thermal stress-induced distortions, stabilizes vibration characteristics, and reduces frequency changes, even under temperature cycles, enhancing the performance of quartz crystal oscillators and gyro sensors.

Implementation Method 1

the hysteresis occurs due to an occurrence of a thermal distortion caused by a difference in a thermal expansion coefficient with a container (package) in a supporting portion supporting a quartz crystal vibrator element

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS12034433B2Vibrator device, oscillator, gyro sensor, electronic apparatus, and vehicle

Publication Date: 2024.07.09 SEIKO EPSON CORP

AI summary

A vibrator device includes a vibration element including a vibration portion and a fixed portion, a supporting member to which the fixed portion is attached to support the vibration element, and a first substrate to which the supporting member is attached, the supporting member includes a attaching portion attached to the first substrate, and A1≥A2 is satisfied in a case where an area of a rectangular region including the fixed portion is A1 and an area of a rectangular region including the attaching portion is A2 in a plan view seen from a thickness direction of the vibration element.