Elastic Wave Reflector Layout to Prevent Pass Band Ripples
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Solution Overview
Problem
Elastic wave devices face challenges in size reduction while maintaining characteristics due to ripples in the pass band caused by shared reflectors or short distances between adjacent reflectors, leading to inefficient vibration leakage and characteristic deterioration.
Innovation Solution
Incorporating reflection members between adjacent elastic wave elements that reflect waves in directions different from the propagation direction, arranged in a specific configuration such as perpendicular to the propagation direction, with shapes like circular, rectangular, or oval, and inclined orientations to effectively scatter or reflect vibrations, thereby preventing leakage and maintaining device characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a reflector is used in common between two adjacent elastic wave elements, then the device size is reduced, but ripples occur in the pass band
Solution Approach 1:
The invention divides the reflector structure into separate segments for adjacent elastic wave elements. Instead of using a common reflector, each elastic wave element has its own dedicated reflector, preventing the interference that causes ripples in the pass band while maintaining compact spacing between elements.
Solution Approach 2:
The invention introduces a reflective member as an intermediary structure positioned between adjacent elastic wave elements. This reflective member reflects elastic waves that would otherwise propagate between elements, preventing vibration leakage and characteristic deterioration while allowing the elements to be closely spaced.
2Volume of moving object
If the distance between adjacent reflectors is shortened, then the device size is reduced, but ripples occur in the pass band
Solution Approach 1:
The reflective member acts as an intermediary that enables short spacing between reflectors without causing pass band ripples. By positioning reflective members between adjacent elastic wave elements, the invention allows compact layout while preventing the vibration leakage that would occur with short reflector spacing.
Solution Approach 2:
The invention extracts the vibration leakage problem by introducing reflective members that specifically target and reflect waves propagating between elements. This allows the main reflectors to be positioned close together while the reflective members handle the interference control.
3Volume of moving object
If elastic wave elements are placed adjacent to each other, then the device size is reduced, but vibration leakage occurs and characteristics deteriorate
Solution Approach 1:
The reflective member serves as an intermediary barrier between adjacent elastic wave elements. It reflects elastic waves that would otherwise leak between elements, preventing vibration leakage and characteristic deterioration while enabling the elements to be placed adjacent to each other for compact device size.
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 solution allows for a smaller size of the elastic wave device while maintaining its performance by reducing vibration leakage and preventing characteristic deterioration, even with closely spaced elastic wave elements.
Implementation Method 1
a reflection member between the first and second reflectors, the reflection member reflecting elastic waves in at least a direction different from the propagation direction of elastic waves
Data Source
AI summary
An elastic wave device includes a piezoelectric substrate, a first elastic wave element on the piezoelectric substrate and including at least one first interdigital transducer electrode and a first reflector in an area of the first interdigital transducer electrode at one side in a propagation direction of elastic waves, and a second elastic wave element on the piezoelectric substrate and including at least one second interdigital transducer electrode and a second reflector in an area of the second interdigital transducer electrode at one side in the propagation direction of elastic waves. The first and second reflectors are disposed side by side in the propagation direction. A reflection member, between the first and second reflectors, reflects elastic waves in at least a direction different from the propagation direction.