Multi-Substrate Filter Layout for Electrode Thickness Optimization

Solution Overview

Problem

Existing filter technologies face challenges in achieving optimal electrical characteristics and productivity due to the need for multiple electrode thicknesses on a single substrate, which complicates the fabrication process and reduces productivity.

Innovation Solution

The filter consists of a ladder filter portion and a multi-mode filter portion formed on separate piezoelectric substrates, allowing for different electrode thicknesses to be optimized for each portion without complicating the fabrication process, enhancing the filter's electrical characteristics and productivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple electrode thicknesses are used on a single substrate to optimize different filter portions, then electrical characteristics are improved, but fabrication complexity increases and productivity decreases

Engineering Contradiction:

Improveelectrical characteristicsVSAvoidproductivity

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The filter device is divided into two separate piezoelectric substrates: a first substrate for the ladder filter portion and a second substrate for the multi-mode filter portion. This segmentation allows each substrate to have uniformly thick electrodes optimized for its specific filter type, eliminating the need for complex multi-thickness electrode fabrication on a single substrate while maintaining optimal electrical characteristics for both filter portions.

Inventive Principle:

Principle #1Segmentation

2Reliability

If multiple electrode thicknesses are used on a single substrate to optimize different filter portions, then electrical characteristics are improved, but device complexity increases

Engineering Contradiction:

Improveelectrical characteristicsVSAvoidfabrication process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The filter device is divided into two separate piezoelectric substrates: a first substrate for the ladder filter portion and a second substrate for the multi-mode filter portion. This segmentation allows each substrate to have uniformly thick electrodes optimized for its specific filter type, eliminating the need for complex multi-thickness electrode fabrication on a single substrate while maintaining optimal electrical characteristics for both filter portions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The multi-mode filter portion is extracted from the first substrate and placed on a separate second substrate. This extraction eliminates the need to create varying electrode thicknesses on the first substrate, simplifying its fabrication process while allowing the second substrate to be optimized specifically for multi-mode filter requirements.

Inventive Principle:

Principle #2Taking out (Extraction)

3Volume of moving object

If a single substrate is used for both ladder filter and multi-mode filter portions, then device size is reduced, but electrode thickness optimization becomes difficult

Engineering Contradiction:

Improvedevice sizeVSAvoidelectrode thickness optimization

Core Design Contradiction:

Volume of moving objectVSManufacturing precision

Solution Approach 1:

The filter device is divided into two separate piezoelectric substrates: a first substrate for the ladder filter portion and a second substrate for the multi-mode filter portion. This segmentation allows each substrate to have uniformly thick electrodes optimized for its specific filter type, eliminating the need for complex multi-thickness electrode fabrication on a single substrate while maintaining optimal electrical characteristics for both filter portions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Each piezoelectric substrate is designed with uniform electrode thickness optimized for its specific filter type: the first substrate has electrode thickness optimized for ladder filter performance, while the second substrate has electrode thickness optimized for multi-mode filter performance. This local optimization ensures peak electrical characteristics for each filter portion without compromising the other.

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 enables improved electrical characteristics and increased productivity by allowing for distinct electrode thickness optimizations for each filter portion, reducing insertion loss and maintaining high sharpness, while also allowing for easier handling and reduced size of the multi-filter.

Implementation Method 1

an elastic wave device that applies a voltage to an IDT (interdigital transducer) electrode on a piezoelectric body to produce an elastic wave that propagates through the piezoelectric body

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentUS12113513B2Filter and multi-filter

Publication Date: 2024.10.08 KYOCERA CORP

AI summary

A filter includes a ladder filter portion formed on a first piezoelectric substrate; and a multi-mode filter portion connected to the ladder filter portion and formed on a second piezoelectric substrate different from the first piezoelectric substrate. The ladder filter portion and the multi-mode filter portion constitute a single passband.