MEMS Electroacoustic Transducer Frame for Reverse-Phase Sound Isolation
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Solution Overview
Problem
Existing acoustic devices, particularly piezoelectric-driven MEMS speaker drivers, face challenges in achieving high sound pressure levels and efficient miniaturization due to issues with sound wave interference and structural limitations.
Innovation Solution
The electroacoustic transducer design includes a diaphragm, diaphragm supports, a driver, driver support, a base, and a frame, with a gap between the diaphragm and driver, utilizing a MEMS process to form components like silicon and piezoelectric actuators, and a frame structure that prevents reverse-phase sound waves from interfering, enhancing sound pressure levels and reducing distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If piezoelectric-driven MEMS speaker drivers are used for miniaturization, then device size is reduced, but sound pressure level and performance are compromised
Solution Approach 1:
The driver is divided into multiple independent piezoelectric actuator units (first driver unit, second driver unit, etc.) that can be independently controlled. This segmentation allows each unit to contribute to sound pressure generation without requiring a large overall driver size, resolving the contradiction between miniaturization and sound pressure level by distributing the acoustic output across multiple smaller elements.
Solution Approach 2:
Multiple piezoelectric actuator units are combined in a specific arrangement where their acoustic outputs are integrated. The first and second driver units, along with other actuators, work together to generate enhanced sound pressure levels despite each individual unit being small, thus achieving high SPL in a miniaturized device through constructive combination of multiple small sources.
2Volume of moving object
If the driver is positioned close to the diaphragm for compact design, then device size is reduced, but reverse-phase sound waves cause interference and distortion
Solution Approach 1:
A driver support structure is introduced as an intermediary element between the driver and the diaphragm. This support structure includes specific geometric features (such as support beams or reflective surfaces) that manage the propagation of reverse-phase sound waves, preventing them from interfering with the primary acoustic output while maintaining a compact overall device size.
Solution Approach 2:
The problem of sound wave interference in the vertical dimension (between driver and diaphragm) is addressed by introducing spatial arrangement in horizontal dimensions. The multiple driver units are positioned at different lateral locations, and the driver support structure extends in multiple dimensions to redirect or contain reverse-phase waves, transforming a one-dimensional interference problem into a multi-dimensional spatial management solution.
3Volume of moving object
If structural components are minimized for miniaturization, then device size is reduced, but manufacturing precision and assembly difficulty increase
Solution Approach 1:
The driver support structure serves multiple functions simultaneously: it provides mechanical support for the compactly arranged driver units, manages sound wave propagation, and acts as a positioning reference for assembly. This multi-functionality reduces the need for additional separate components, thereby maintaining manufacturing precision while achieving miniaturization through integrated design rather than proliferation of small parts.
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 achieves improved sound pressure levels and reduced total harmonic distortion (THD) by optimizing the structural arrangement and materials, allowing for efficient manufacturing and increased performance in miniaturized devices.
Implementation Method 1
piezoelectric-driven MEMS speaker drivers using piezoelectric membranes
Implementation Method 2
issues with sound wave interference
Data Source
AI summary
An electroacoustic transducer includes a diaphragm, a diaphragm support connected to a part of the diaphragm in a direction of vibration of the diaphragm, a driver connected to the diaphragm support to vibrate the diaphragm, a driver support connected to the driver opposite to the diaphragm to support a part of the driver, a base connected to the driver support and having a larger area than the diaphragm, and a frame connected to the base from a same side as the driver support and disposed within a gap between an outside of the diaphragm and an outside of the driver.