Elastic Wave Substrate Edge Geometry for Spurious Signal Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing elastic wave devices face challenges in effectively reducing spurious signals while maintaining the intensity of main vibrations due to suboptimal design configurations of electrode fingers and end surfaces, leading to compromised frequency characteristics.
Innovation Solution
The elastic wave device incorporates a piezoelectric body with a first end surface forming an angle of 70° to 90° with the surface and a height of 0.5 to 2.0 times the electrode finger interval, along with floating electrodes positioned near the end surface to reflect and leak spurious signals, enhancing the design to improve frequency characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the end surface is designed with a specific angle (70° to 90°) and height (0.5 to 2.0 times electrode finger interval), then spurious signals are reduced, but the device complexity increases due to additional geometric constraints
Solution Approach 1:
The patent applies parameter changes by optimizing specific geometric parameters of the end surface (angle between 70° to 90° and height between 0.5 to 2.0 times the electrode finger interval). These parameter modifications enable effective reduction of spurious signals while maintaining manufacturability, resolving the contradiction between performance improvement and complexity increase.
2Reliability
If floating electrodes are added near the end surface to reflect and leak spurious signals, then frequency characteristics are improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The floating electrodes serve as intermediary elements positioned between the IDT electrodes and the end surface. These intermediary electrodes reflect and leak spurious signals while maintaining electrical independence, thereby improving frequency characteristics without requiring fundamental redesign of the core IDT structure.
Solution Approach 2:
The electrode system is segmented into functional zones: the IDT electrodes for primary signal generation and the floating electrodes for spurious signal management. This segmentation allows each electrode group to perform its specific function independently, improving overall frequency characteristics while keeping the manufacturing process manageable through modular design.
3Object-generated harmful factors
If the end surface height is increased within the range of 0.5 to 2.0 times the electrode finger interval, then spurious signal reduction is enhanced, but the manufacturing precision requirements increase
Solution Approach 1:
The patent defines a specific parameter range for end surface height (0.5 to 2.0 times the electrode finger interval) that balances spurious signal reduction effectiveness with manufacturing feasibility. This parameter specification resolves the contradiction by providing a practical design window that achieves performance goals without requiring extreme manufacturing precision.
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 improved design effectively reduces spurious signals while maintaining the intensity of main vibrations, resulting in enhanced frequency characteristics and improved performance of the elastic wave device.
Implementation Method 1
a piezoelectric body having a first surface; and an electrode including an IDT electrode including a plurality of electrode fingers arrayed on the first surface
Implementation Method 2
on a cross-section obtained by cutting the piezoelectric body on a plane parallel to the first direction and perpendicular to the first surface, a first angle formed by an extended line of the first surface in the first direction and a tangential line at any point on the first end surface is 70° or greater and less than 90°
Data Source
AI summary
To improve frequency characteristics of an elastic wave device. The elastic wave device includes a piezoelectric body having a first surface and an electrode including an IDT electrode on the first surface. The piezoelectric body has a first end surface connected to the first surface, the first end surface being an end surface positioned on a first side in a first direction that is orthogonal to an extending direction of any of electrode fingers. A first angle formed by an extended line of the first surface and a tangential line at any point on the first end surface is less than 90°.