Integrated MEMS Electrostatic Micro-Speaker for PCB Compatibility
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Solution Overview
Problem
Conventional speakers, particularly those used in consumer devices like smartphones and earbuds, face challenges due to their size, compatibility with PCB technology, and interference with other components due to the use of magnets, which limits their placement and integration in miniaturized devices.
Innovation Solution
A MEMS speaker device utilizing a silicon or graphene diaphragm actuated by electrostatic forces, integrated with CMOS audio processing, allows for miniaturization and integration with semiconductor technologies, eliminating the need for magnets and enabling placement without interference with other electronics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional cone speaker technology with magnets is used, then acoustic performance is achieved, but device size and interference with other components increase
Solution Approach 1:
The patent replaces the electromagnetic actuation system (with magnets and voice coils) with a MEMS electrostatic actuation system. The movable diaphragm is actuated by electrostatic forces generated by electrodes on the CMOS device, eliminating the need for permanent magnets and large electromagnetic components. This substitution enables miniaturization while maintaining acoustic functionality.
Solution Approach 2:
The patent changes the fundamental operating parameters of the speaker by using electrostatic forces instead of electromagnetic forces. The movable diaphragm thickness is reduced to 0.1 nm to ten microns, and the actuation mechanism operates at the micro-electromechanical scale, allowing the speaker to fit within constrained spaces in consumer devices without interfering with other components.
2Adaptability or versatility
If conventional electromagnetic speaker design is used, then acoustic output is achieved, but integration with PCB technology and miniaturized devices becomes difficult
Solution Approach 1:
The patent merges the speaker acoustic output function with CMOS audio processing functionality into a single integrated device. The CMOS device includes both the electrostatic actuation electrodes and the audio signal processing circuits, allowing the speaker to be directly integrated with the device's existing PCB and electronic systems. This consolidation eliminates the need for separate magnetic components and simplifies integration.
Solution Approach 2:
The integrated device serves multiple functions: the CMOS device provides both the electrostatic actuation mechanism and the audio signal processing, while the movable diaphragm provides both the acoustic output and serves as the electrostatic actuator target. This multi-functionality reduces the number of separate components needed and enhances compatibility with miniaturized consumer devices.
3Volume of moving object
If speaker size is reduced for miniaturized devices, then device compactness is improved, but manufacturing precision and control become more difficult
Solution Approach 1:
The patent specifies a diaphragm thickness range of 0.1 nm to ten microns, which can be controlled using conventional semiconductor and MEMS fabrication processes. By operating at this micro-scale thickness range, the manufacturing precision requirements are aligned with existing industrial capabilities, enabling mass production while achieving the desired miniaturization for consumer devices.
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 MEMS speaker device achieves reduced size and profile height without compromising performance, integrating CMOS audio processing to enhance compatibility with miniaturized consumer devices like earbuds and smartwatches, and facilitates wide-scale commercialization using conventional semiconductor and MEMS process technologies.
Implementation Method 1
A MEMS speaker device utilizing a silicon or graphene diaphragm actuated by electrostatic forces
Implementation Method 2
cap device comprising a plurality of vent regions for propagating acoustic signals
Data Source
AI summary
In an example, the present invention provides a micro-speaker device. The device has a movable diaphragm device comprising a thickness of silicon or graphene material which has a first surface and a second surface opposite of the first surface. The device has a housing enclosing the movable diaphragm device, the electrode device and an encapsulation device. The electrode device can be part of a CMOS device with electronics integrated on to the device. The device has a vented enclosure opposite of the movable diaphragm to allow air to move in and out of the one or more vent openings to generate a sound pressure signal. The diaphragm can be electrostatically actuated from one or more surfaces that include the electrode device and the encapsulation device.