Embedded Piezoelectric Elastic Wave Element in PCB Cavity

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The miniaturization of electronic devices has led to a demand for printed circuit boards with reduced mounting areas for elastic wave elements, while existing technologies face challenges in preventing defects such as cracks and moisture permeation during the mounting of these elements.

Innovation Solution

A printed circuit board design featuring a cavity in a core layer with a piezoelectric substrate, an electrode, and a sealing part that forms an air gap around the electrode, using a non-conductive material to prevent moisture ingress and reduce the mounting area, along with a method of manufacturing that includes forming the cavity and injecting piezoelectric material to create the substrate and electrode.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If elastic wave elements are mounted on the surface of the printed circuit board, then the board can provide electrical connection and support, but the mounting area increases and defects such as cracks and moisture permeation may occur

Engineering Contradiction:

Improvedefect preventionVSAvoidmounting area

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The elastic wave element is embedded within a cavity formed in the core layer of the printed circuit board, nesting the element inside the board structure rather than mounting it on the surface. This reduces the mounting area while maintaining electrical connection through vias that pass through the board to connect to the electrode on the piezoelectric substrate.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The invention transitions from surface mounting (2D placement) to embedded mounting (3D integration). By forming a cavity in the core layer and placing the piezoelectric substrate with electrode inside, the element is integrated into the board's thickness dimension, reducing the footprint area while maintaining functionality.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If the electrode is exposed without sealing, then the structure remains simple, but moisture can permeate and cause corrosion

Engineering Contradiction:

Improvecorrosion resistanceVSAvoidsealing structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

A sealing part formed from a non-conductive material is placed over the piezoelectric substrate to enclose the electrode. This thin film-like sealing structure prevents moisture permeation and corrosion while maintaining the simplicity of the overall device design.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

An air gap is created between the sealing part and the electrode, providing an inert or controlled environment that protects the electrode from moisture and corrosion. The air gap acts as a protective barrier without requiring direct contact between the sealing material and the electrode.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

3Area of stationary object

If the mounting area is reduced for miniaturization, then space utilization improves, but the elastic wave element may not fit or function properly

Engineering Contradiction:

Improvemounting areaVSAvoidelement functionality

Core Design Contradiction:

Area of stationary objectVSReliability

Solution Approach 1:

The elastic wave element is nested within the cavity of the core layer, allowing it to occupy three-dimensional space rather than only surface area. This enables miniaturization of the mounting footprint while maintaining sufficient space for the element's proper dimensions and functionality.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

By utilizing the vertical dimension (embedding within the board thickness) rather than only horizontal surface area, the invention achieves miniaturization of the mounting footprint while preserving the elastic wave element's required dimensions and operational space.

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 design reduces the mounting area for elastic wave elements, prevents defects like cracks and moisture ingress, and enhances space utilization by forming the elastic wave element within the circuit board, ensuring reliable operation.

Implementation Method 1

a piezoelectric substrate disposed in the cavity; an electrode disposed on the piezoelectric substrate and configured to convert an electrical signal into an elastic wave or to convert an elastic wave into an electrical signal

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentUS10193055B2Printed circuit board and method of manufacturing the same

Publication Date: 2019.01.29 SAMSUNG ELECTRO MECHANICS CO LTD

AI summary

A printed circuit board includes: insulating layers and wiring layers arranged in stacked configuration; a cavity disposed in a first insulating layer among the insulating layers; a piezoelectric substrate disposed in the cavity; an electrode disposed on the piezoelectric substrate and configured to convert an electrical signal into an elastic wave or to convert an elastic wave into an electrical signal; and a sealing part disposed on the piezoelectric substrate, the sealing part enclosing the electrode and forming an air gap around the electrode.