AT-Cut Crystal Resonator Plate Structure for Vibration Confinement

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Solution Overview

Problem

Conventional AT-cut crystal resonators experience vibration leakage and reduced efficiency due to dominant vibration in the X-axis direction, leading to inefficient piezoelectric vibration when held in this direction, which degrades the overall vibration efficiency.

Innovation Solution

The AT-cut crystal resonator plate is designed with holding parts protruding from corner parts in the Z′ axis direction, allowing the vibrating part to be securely held by an external frame, preventing vibration leakage and reducing parasitic capacitance, while the mesa structure and groove configurations enhance vibration confinement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the crystal resonator plate is held in the X-axis direction where piezoelectric vibration is dominant, then the vibration can be effectively coupled to the support frame, but vibration leakage occurs which reduces piezoelectric vibration efficiency

Engineering Contradiction:

Improvevibration coupling effectivenessVSAvoidpiezoelectric vibration efficiency

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies asymmetry by positioning holding parts at specific locations that are not symmetrically distributed along the X-axis vibration direction. The holding parts are arranged to minimize interference with the dominant piezoelectric vibration mode while providing adequate mechanical support, thereby reducing vibration leakage and improving vibration efficiency.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The patent introduces holding parts that extend in the Z-axis direction (perpendicular to the main vibration plane) rather than only along the X-axis direction. This dimensional change allows the holding parts to provide mechanical support while minimizing coupling with the dominant X-axis piezoelectric vibration, thus reducing energy loss.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Strength

If holding parts are added to secure the vibrating part to the frame, then mechanical stability and shock resistance are improved, but parasitic capacitance increases which may affect frequency stability

Engineering Contradiction:

Improveshock resistanceVSAvoidfrequency stability

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The holding parts serve as intermediaries between the vibrating part and the frame, providing mechanical support while being designed to minimize electrical coupling. The holding parts are positioned and shaped to act as mechanical mediators that transmit shock resistance benefits while limiting parasitic capacitance formation.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The holding parts are designed with specific local properties - their shape, size, and material characteristics are optimized to provide adequate mechanical strength for shock resistance while minimizing their electrical capacitance. The local quality of the holding parts is tailored to balance mechanical and electrical requirements.

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 improves piezoelectric vibration efficiency by confining vibrations within the resonator, reducing frequency shifts, and enhancing shock resistance, resulting in a more stable and efficient crystal resonator device.

Implementation Method 1

an AT-cut crystal resonator plate including a first main surface on which a first excitation electrode is formed and a second main surface on which a second excitation electrode are formed

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

holding parts protruding from corner parts in the Z′ axis direction, allowing the vibrating part to be securely held by an external frame, preventing vibration leakage

Methodology Applied

Scientific EffectVibration confinement: Physical Containment

Implementation Method 3

reducing parasitic capacitance

Methodology Applied

Scientific EffectParasitic capacitance reduction: Parasitic Capacitance

Data Source

PatentUS10601393B2Crystal resonator plate and crystal resonator device

Publication Date: 2020.03.24 DAISHINKU CORP

AI summary

An AT-cut crystal resonator plate (2) includes a first main surface (2a) on which a first excitation electrode (211) is formed and a second main surface (2b) on which a second excitation electrode (212) is formed. The AT-cut crystal resonator plate (2) further includes: a substantially rectangular-shaped vibrating part (21) that is piezoelectrically vibrated when a voltage is applied to the first excitation electrode (211) and the second excitation electrode (212); a holding part (22) protruding from a corner part (21a) of the vibrating part (21) in a Z′ axis direction of the AT-cut crystal; and an external frame part (23) configured to surround an external circumference of the vibrating part (21) and to hold the holding part (22).