Acoustic Wave Resonator Support Layout for Unnecessary Wave Suppression
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Solution Overview
Problem
Existing acoustic wave devices suffer from deterioration of electrical characteristics due to unnecessary waves propagating on the surface of the piezoelectric substrate, which affects their performance.
Innovation Solution
The acoustic wave device incorporates a piezoelectric substrate with a support and a piezoelectric layer, featuring a configuration where additional supports are placed to overlap the intersecting region of the IDT electrodes, effectively scattering unnecessary waves and preventing their propagation to the acoustic wave resonators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a piezoelectric substrate with IDT electrodes is used to form an acoustic wave resonator, then acoustic wave resonance can be achieved, but unnecessary waves propagate on the surface of the piezoelectric substrate causing deterioration of electrical characteristics
Solution Approach 1:
A lossy layer is introduced as an intermediary between the piezoelectric substrate and the unnecessary wave propagation path. This lossy layer absorbs the unnecessary waves (surface acoustic waves) before they can propagate and interfere with the electrical characteristics of the acoustic wave resonator, thereby resolving the contradiction between achieving resonance and preventing harmful wave propagation
Solution Approach 2:
The invention converts the harmful unnecessary waves into beneficial energy dissipation by designing the lossy layer to specifically absorb surface acoustic waves. The harmful wave energy is transformed into heat within the lossy layer, preventing the waves from causing electrical characteristic deterioration while maintaining the desired acoustic wave resonance function
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 significantly reduces or prevents the deterioration of electrical characteristics, enhancing the device's performance by minimizing the impact of unnecessary waves on the acoustic wave resonators.
Implementation Method 1
the piezoelectric layer being provided on the support and including a first main surface and a second main surface opposed to each other, one or more functional electrodes provided on the first main surface or the second main surface of the piezoelectric layer
Implementation Method 2
a plurality of acoustic wave resonators are provided on the piezoelectric substrate... each including a pair of electrodes... adjacent to each other in a first direction... adjacent to each other in a second direction that intersects the first direction
Data Source
AI summary
An acoustic wave device includes a piezoelectric substrate including a support and a piezoelectric layer provided on the support and including first and second main surfaces, one or more functional electrodes provided on the first or second main surface, and including at least one pair of electrodes, a first support provided on the piezoelectric substrate so as to surround the functional electrodes, one or more second supports provided on the piezoelectric substrate and on a portion surrounded by the first support, and a cover on the first support and the second supports. A direction in which adjacent electrodes face each other is an electrode facing direction, a region in which the adjacent electrodes overlap each other when viewed from the electrode facing direction is an intersecting region, and the second support at least partially overlaps the intersecting region when viewed from the electrode facing direction.