Acoustic wave device
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Solution Overview
Problem
Existing acoustic wave devices face challenges in effectively suppressing the generation of higher-order modes near the main mode, particularly in devices using polycrystalline spinel layers.
Innovation Solution
The use of a monocrystalline spinel substrate made of magnesium aluminate single crystal, combined with a piezoelectric layer and an IDT electrode, where the Euler angles (ϕ, θ, ψ) are set within specific ranges to adjust the acoustic velocity of the transversal wave, effectively suppressing higher-order modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a polycrystalline spinel layer is used in the acoustic wave device, then the device structure can be simplified and manufacturing can be facilitated, but the generation of higher-order modes near the main mode cannot be sufficiently suppressed
Solution Approach 1:
The patent changes the fundamental parameter of the substrate material from polycrystalline to monocrystalline magnesium aluminate spinel. This parameter change enables precise control of acoustic wave propagation characteristics through controlled Euler angles (φ, θ, ψ), effectively suppressing higher-order mode generation while maintaining manufacturing feasibility through established monocrystalline growth techniques.
Solution Approach 2:
The patent employs a composite structure consisting of monocrystalline magnesium aluminate spinel substrate with specific Euler angle orientation combined with piezoelectric layer and IDT electrode. This composite approach leverages the anisotropic properties of the monocrystalline spinel at specific orientations to suppress higher-order modes while maintaining device functionality.
2Speed
If the Euler angles of the monocrystalline spinel substrate are adjusted to suppress higher-order modes, then the acoustic velocity can be optimized, but the device complexity increases due to precise angle requirements
Solution Approach 1:
The patent optimizes the acoustic velocity parameter by precisely controlling the Euler angles (φ, θ, ψ) of the monocrystalline magnesium aluminate spinel substrate. Specific angle ranges are identified that provide optimal acoustic velocity characteristics while suppressing higher-order modes, balancing performance optimization with manufacturing considerations.
Solution Approach 2:
The patent identifies specific Euler angle ranges that provide effective higher-order mode suppression without requiring excessively precise angle control. This approach uses sufficiently precise (but not ultra-precise) angle specifications that can be achieved with conventional manufacturing tolerances, avoiding the need for complex alignment systems and expensive manufacturing processes.
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 allows for the effective suppression of higher-order modes by adjusting the acoustic velocity, enhancing the performance of the acoustic wave device by maintaining the main mode's frequency characteristics and reducing interference.
Implementation Method 1
a piezoelectric layer on the monocrystalline spinel substrate
Implementation Method 2
an IDT electrode on the piezoelectric layer
Data Source
AI summary
An acoustic wave device includes a monocrystalline spinel substrate made of a magnesium aluminate single crystal, a piezoelectric layer on the monocrystalline spinel substrate, and an IDT electrode on the piezoelectric layer. Euler angles (ϕ, θ, ψ) of the magnesium aluminate single crystal of the monocrystalline spinel substrate are within a range of any of regions A in FIGS. 5 to 41.