Ultrasonic Transducer Acoustic Path Tuning for Wideband Sound Pressure
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Solution Overview
Problem
Existing ultrasonic transducers struggle to radiate ultrasound at a high sound pressure level over a wide frequency band due to the difficulty in separating and adjusting the resonance frequencies of the acoustic MEMS device and the acoustic path.
Innovation Solution
The ultrasonic transducer design incorporates an acoustic path that resonates with the MEMS device, allowing for a specific relationship between resonance frequencies (f0 and f1) to achieve a sound pressure level difference within a defined range, enabling radiation of ultrasound over a wide frequency band.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the resonance frequency of the acoustic MEMS device is adjusted independently from the acoustic path resonance frequency, then the sound pressure level can be optimized, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent merges the acoustic MEMS device with the acoustic path structure, where the housing and internal components form an integrated acoustic resonance system. This integration allows the acoustic path resonance frequency to be inherently coupled with the MEMS device resonance frequency, eliminating the need for independent adjustment mechanisms and reducing device complexity while maintaining sound pressure level stability.
Solution Approach 2:
The patent utilizes parameter changes in the acoustic path geometry (volume, shape, and configuration) to adjust the acoustic resonance frequency. By modifying physical dimensions and structural parameters of the housing and acoustic components, the system achieves frequency optimization without adding complex adjustment mechanisms, thereby resolving the contradiction between reliability and device complexity.
2Adaptability or versatility
If the acoustic path is designed to resonate at a frequency close to the MEMS device resonance frequency, then a wide frequency band with high sound pressure level is achieved, but the design precision requirements increase
Solution Approach 1:
The patent incorporates adjustable and reconfigurable acoustic path elements that allow dynamic tuning of the acoustic resonance frequency. This dynamic capability enables the system to adapt to different frequency requirements and compensates for manufacturing tolerances, reducing the stringency of manufacturing precision requirements while maintaining wide frequency band coverage with high sound pressure level.
3Ease of operation
If through holes are provided in both the substrate and mount substrate for acoustic communication, then the acoustic path is established, but the structural integrity and sealing difficulty increase
Solution Approach 1:
The patent employs asymmetric design where the through hole in the substrate and the through hole in the mount substrate are positioned at different locations and have different dimensions. This asymmetric configuration optimizes the acoustic path establishment while reducing alignment complexity during assembly, as the components are designed to mate in a specific orientation that naturally facilitates proper acoustic communication without requiring precise concentric alignment.
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 design enables stable high sound pressure ultrasound radiation over a wide frequency band, reducing variations in sound pressure characteristics and enhancing robustness by maintaining a consistent sound pressure level across the frequency range.
Implementation Method 1
ultrasound generated by vibration of the acoustic MEMS device
Implementation Method 2
In the acoustic path, ultrasound generated by vibration of the acoustic MEMS device can resonate
Data Source
AI summary
An acoustic device includes an acoustic MEMS device. An acoustic path communicates with the acoustic MEMS device. Ultrasound generated by vibration of the acoustic MEMS device can resonate in the acoustic path. An ultrasonic transducer has sound pressure frequency characteristics such that sound pressure peaks occur as a result of a combination of resonance of the acoustic MEMS device and resonance in the acoustic path. A relationship of about 5≤(f0−fl)/f0×100≤about 33 is satisfied, where f0 represents a resonance frequency of the acoustic MEMS device and fl represents a frequency lower than the resonance frequency and closest to the resonance frequency among frequencies at which the sound pressure peaks occur in the sound pressure frequency characteristics.