Rectangular Crystal Element Structure for Spurious Vibration Suppression

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Solution Overview

Problem

The rectangular shape of crystal elements leads to significant influence of contour and spurious vibrations on thickness shear vibrations, deteriorating electrical characteristics due to external size and vibration leakage.

Innovation Solution

The crystal element features convex and concave parts on its short-sides, dispersing contour vibration frequencies and extending the length between excitation electrode ends, reducing the impact of reflected vibrations on main vibrations, and incorporating recessed parts to enhance bonding strength and prevent short-circuits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a rectangular crystal piece is used, then the manufacturing is simple and the structure is compact, but contour and spurious vibrations significantly influence the thickness shear vibrations, deteriorating electrical characteristics

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidelectrical characteristics

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent introduces asymmetric convex and concave parts on the crystal piece to break the symmetry of the rectangular shape. Specifically, convex parts are provided on two opposite short sides while concave parts are provided on the other two opposite short sides, creating an asymmetric structure that suppresses contour vibrations and spurious vibrations while maintaining manufacturing feasibility.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The patent uses curved surfaces instead of sharp corners by providing convex parts with curved outer surfaces and concave parts with curved inner surfaces. This curvature design reduces stress concentration and suppresses the generation of spurious vibrations at the corners, thereby improving electrical characteristics while maintaining a compact structure.

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Device complexity

If the crystal piece has straight-line sides, then the structure is simple, but vibration leakage occurs at the ends, causing spurious vibrations to influence the main vibrations

Engineering Contradiction:

Improvestructural simplicityVSAvoidvibration leakage

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent segments the continuous straight sides of the rectangular crystal piece by introducing convex and concave parts. This segmentation divides the vibration paths and prevents the propagation of spurious vibrations along the entire perimeter, effectively reducing vibration leakage while maintaining structural simplicity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent converts the harmful effect of vibration leakage at the corners into a beneficial effect by designing convex and concave parts that redirect the vibrations. The curved surfaces of these parts cause the spurious vibrations to reflect in directions that do not interfere with the main thickness shear vibrations, thereby converting harmful vibration leakage into a neutral or beneficial effect.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If convex and concave parts are added to the crystal piece, then spurious vibrations are suppressed and electrical characteristics improve, but the manufacturing process becomes more complex

Engineering Contradiction:

Improveelectrical characteristicsVSAvoidstructural complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by providing convex and concave parts only at specific locations (the short sides) of the crystal piece rather than modifying the entire structure. This localized modification suppresses spurious vibrations at the critical corners while minimizing the overall structural complexity and maintaining simplicity in other areas.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses partial action by providing convex parts on two opposite short sides and concave parts on the other two opposite short sides, rather than modifying all four sides uniformly. This partial modification is sufficient to suppress spurious vibrations and improve electrical characteristics without unnecessarily increasing structural complexity.

Inventive Principle:

Principle #16Partial or excessive 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

This configuration improves electrical characteristics by minimizing the influence of spurious vibrations on main vibrations, suppressing deterioration and enhancing bonding strength, thereby improving the overall performance of the crystal device.

Implementation Method 1

an excitation electrode part located on both main surfaces of the crystal piece

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentUS11545957B2Crystal element and crystal device

Publication Date: 2023.01.03 KYOCERA CORP

AI summary

Provided is a crystal element that includes: a crystal piece that is in a substantially rectangular shape on a plan view; an excitation electrode part located on both main surfaces of the crystal piece; a connection lead part extended to a first short-side of the crystal piece from the excitation electrode part; a convex part located on both ends of a second short-side of the crystal piece; and a projected part located on both ends of the first short-side of the crystal piece. Further, a concave part is located in the convex part, and a recessed part is located in the projected part.