Crystal Element Recesses Attenuate Secondary Vibrations

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Solution Overview

Problem

Crystal elements with thickness-shear vibration mode experience deterioration in electrical characteristics due to secondary vibrations such as bending and contour vibrations, which combine with primary thickness-shear vibrations, potentially increasing the equivalent series resistance value.

Innovation Solution

Incorporating a recess and/or protrusion at the holding-part side surface of the crystal element, which reduces secondary vibrations by altering the vibration states and improving bonding strength when mounted in a package.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional crystal element structure is used, then the manufacturing process is simple, but secondary vibrations occur causing deterioration in electrical characteristics

Engineering Contradiction:

Improveelectrical characteristicsVSAvoidstructure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by introducing recesses or protrusions specifically at the holding-part side surface, rather than modifying the entire crystal element. This localized structural modification targets the specific region where secondary vibrations originate, improving electrical characteristics without unnecessarily complicating the overall device structure

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The crystal element is divided into distinct functional parts: a vibration part with specific geometry and a holding part with recesses or protrusions. This segmentation allows independent optimization of each part's function, enabling the holding part to suppress secondary vibrations while the vibration part maintains its thickness-shear vibration mode

Inventive Principle:

Principle #1Segmentation

2Strength

If the crystal element is mounted in a package, then bonding strength is required for mechanical integrity, but secondary vibrations increase equivalent series resistance

Engineering Contradiction:

Improvebonding strengthVSAvoidelectrical characteristics

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent introduces asymmetric features (recesses or protrusions) on the holding-part side surface that break the symmetry of the crystal element structure. This asymmetry creates mechanical interlocking with the package substrate, enhancing bonding strength while simultaneously suppressing secondary vibrations that would otherwise degrade electrical characteristics

Inventive Principle:

Principle #4Asymmetry

3Reliability

If recesses and protrusions are added to suppress secondary vibrations, then electrical characteristics improve, but manufacturing complexity increases

Engineering Contradiction:

Improveelectrical characteristicsVSAvoidmanufacturing process

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The recesses or protrusions are formed on the holding part before the crystal element is mounted in the package. This preliminary action allows the structural features to be integrated into the crystal element manufacturing process itself, rather than requiring additional post-assembly steps, thereby maintaining ease of manufacture while achieving improved electrical characteristics

Inventive Principle:

Principle #10Preliminary 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 recess and/or protrusion effectively attenuate secondary vibrations, reducing electrical characteristic deterioration and enhancing bonding strength, thereby maintaining stable oscillation frequencies and mechanical integrity.

Implementation Method 1

The crystal device utilizes the piezoelectric effect and the inverse piezoelectric effect of the crystal element to generate a specified oscillation frequency

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

The crystal device utilizes the piezoelectric effect and the inverse piezoelectric effect of the crystal element to generate a specified oscillation frequency

Methodology Applied

Scientific EffectInverse piezoelectric effect: Converse Piezoelectric Effect

Implementation Method 3

The recess and/or protrusion at the holding-part side surface effectively attenuate secondary vibrations, reducing electrical characteristic deterioration

Methodology Applied

Scientific EffectVibration attenuation: Damping

Data Source

PatentUS20230006124A1Crystal element, crystal device, electronic equipment, and method for manufacturing crystal element

Publication Date: 2023.01.05 KYOCERA CORP

AI summary

A crystal element includes a vibration part, a holding part, an electrode part, and a recess that corresponds to a recess and/or protrusion. The vibration part has a pair of vibration-part main surfaces. The holding part is formed integrally with the vibration part to be connected to an outer edge of vibration part and has a pair of holding-part main surfaces and holding-part side surfaces. The electrode part is provided at the vibration-part main surfaces. The recess is located at the holding-part side surfaces.