Boundary Acoustic Wave Frequency Tuning Through Interface Media Reform
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Solution Overview
Problem
There is a lack of effective methods for adjusting the frequency characteristics of boundary acoustic wave devices after manufacturing, as existing methods for surface acoustic wave devices are not applicable due to the embedded IDT electrode at the interface between the first and second solid media in boundary acoustic wave devices.
Innovation Solution
A method for manufacturing boundary acoustic wave devices involves preparing a laminated structure with an IDT electrode at the interface between the first and second media, and externally providing energy to reform the media to adjust the frequency, using a reform medium layer that can be easily reformed by energy, such as a femtosecond laser beam, to concentrate energy within a specific distance from the interface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a boundary acoustic wave device is manufactured with an IDT electrode embedded at the interface between first and second solid media, then the device achieves a compact structure without requiring a space above the IDT electrode, but the frequency characteristics cannot be adjusted after manufacturing using conventional methods
Solution Approach 1:
The patent segments the second solid medium into two parts: a first region containing the IDT electrode interface and a second region that can be independently reformed. This segmentation allows the frequency adjustment process to affect only the relevant portion of the medium without disrupting the compact embedded structure or requiring access to the IDT electrode itself.
Solution Approach 2:
The patent introduces an intermediary substance that can be introduced into the second region of the second solid medium. This intermediary acts as a mediator between the external energy source and the acoustic wave propagation path, allowing frequency adjustment through energy-induced reformation of the intermediary rather than direct modification of the IDT electrode or interface structure.
2Device complexity
If the IDT electrode is embedded at the interface between first and second solid media, then the package structure is simplified and the device is more compact, but existing frequency adjustment methods that require processing the IDT electrode surface are no longer applicable
Solution Approach 1:
The patent shifts the frequency adjustment approach from the spatial dimension (direct electrode processing) to a different dimension by introducing an intermediary substance into the second region. This dimensional shift allows adjustment without physical access to the embedded electrode, maintaining the simplified package structure while restoring frequency adaptability.
Solution Approach 2:
The patent replaces the mechanical/electrical processing method (direct electrode modification) with an energy-based method. By using energy to reform the second region and modify the intermediary substance properties, frequency adjustment is achieved without mechanical contact with the IDT electrode, preserving the compact embedded design.
3Manufacturing precision
If frequency adjustment is attempted by reforming the second medium opposite to the interface, then the acoustic velocity of the surface portion can be changed, but the second medium at the interface through which the boundary acoustic wave propagates cannot be reformed
Solution Approach 1:
The patent applies local quality by making the second region (where the intermediary is introduced) have different properties from the rest of the second solid medium. This localized modification allows precise frequency control through the intermediary in the second region while leaving the interface region and its acoustic wave propagation characteristics unchanged and stable.
Solution Approach 2:
The patent extracts the frequency adjustment function from the interface region itself and relocates it to the second region through the introduction of an intermediary substance. This extraction allows the interface region to maintain its stable acoustic wave propagation properties while the frequency adjustment function is performed separately in the second region through energy-induced reformation of the intermediary.
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 approach allows for precise and reliable adjustment of frequency characteristics, enabling the production of boundary acoustic wave devices with uniform and stable frequency performance without increasing manufacturing complexity or cost.
Implementation Method 1
a substance 506 that is vaporized by being heated by a laser beam is applied on the inner surface of the cap member 504 in advance. When the surface acoustic wave device 501 is irradiated with a laser beam emitted from thereabove using a laser apparatus 507, the laser beam transmits through the cap member 504. Accordingly, the substance 506 is heated by the laser beam, vaporized, and deposited on the IDT electrode 503 positioned therebelow.
Implementation Method 2
a boundary acoustic wave device that includes an IDT electrode arranged at an interface between first and second solid media and that uses a boundary acoustic wave propagating through the interface
Data Source
AI summary
A method for manufacturing a boundary acoustic wave device includes the steps of preparing a laminated structure in which an IDT electrode is disposed at an interface between first and second solid media and reforming the first medium and/or the second medium by externally providing the laminated structure with energy capable of reaching the inside of the first medium and/or the second medium and thus adjusting a frequency of the boundary acoustic wave device. The above provides a boundary acoustic wave device manufacturing method that enables frequency adjustment to be readily performed with high accuracy.