Integrated MEMS Electrostatic Micro-Speaker for PCB Miniaturization
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Solution Overview
Problem
Conventional speakers occupy large spaces due to their design, which is incompatible with modern consumer devices and affects other components like sensors and electronics, especially in smartphones, and they are not compatible with conventional surface mount Printed Circuit Board (PCB) technology.
Innovation Solution
A MEMS speaker device integrated with a CMOS device, utilizing a movable diaphragm made of silicon or graphene, actuated electrostatically by electrodes, and enclosed in a housing, which processes audio signals to drive the diaphragm, reducing size and integrating audio processing within a monolithic element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional speaker design is used, then speaker functionality is achieved, but device size becomes large and occupies excessive space
Solution Approach 1:
The patent replaces the conventional electromagnetic actuation system with an electrostatic actuation system. The electrostatic speaker uses a diaphragm positioned between two electrodes, where electrostatic forces directly move the diaphragm to produce sound, eliminating the need for electromagnetic coils, magnets, and associated mechanical components. This substitution enables significant miniaturization while maintaining speaker functionality.
Solution Approach 2:
The patent integrates multiple functions into a single monolithic device structure. The electrostatic speaker combines the diaphragm, electrodes, and acoustic chamber into one integrated unit that can be directly mounted on a PCB, eliminating the need for separate speaker assemblies and reducing overall device volume.
2Ease of manufacture
If conventional speaker design is used, then speaker functionality is achieved, but compatibility with surface mount PCB technology is lost
Solution Approach 1:
The electrostatic speaker design uses planar electrodes and a thin diaphragm that can be fabricated using standard PCB manufacturing techniques such as photolithography, etching, and lamination. This replaces the complex three-dimensional electromagnetic assembly with a two-dimensional structure suitable for surface mount technology.
Solution Approach 2:
The speaker design serves multiple functions within a single structure: the PCB substrate acts as both the circuit board and the speaker housing, the electrodes serve both electrical and acoustic functions, and the diaphragm provides both structural support and acoustic output. This multi-functionality simplifies manufacturing and enhances PCB compatibility.
3Object-affected harmful factors
If conventional speaker with magnets is used, then speaker functionality is achieved, but interference with sensors and electronics occurs
Solution Approach 1:
The patent completely removes the magnetic field-generating components (permanent magnets and electromagnetic coils) from the speaker design. The electrostatic actuation system uses only electric fields to move the diaphragm, eliminating the source of magnetic interference that would affect nearby sensors and electronic components in smartphones and other consumer devices.
Solution Approach 2:
By substituting the electromagnetic actuation system with an electrostatic system, the patent eliminates the magnetic field generation mechanism while maintaining the core function of converting electrical signals to acoustic output through direct electrostatic force on the diaphragm.
4Volume of moving object
If speaker miniaturization is pursued, then device integration is improved, but manufacturing complexity increases
Solution Approach 1:
The speaker design leverages the PCB substrate to perform multiple functions: structural support, electrical connectivity, and acoustic chamber formation. This eliminates the need for separate housing components and simplifies the manufacturing process despite the miniaturized scale.
Solution Approach 2:
The electrostatic design uses planar structures and thin-film technologies that are compatible with standard PCB manufacturing processes, avoiding the need for complex three-dimensional assembly operations required by traditional electromagnetic speakers.
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 miniaturizes the audio chain without affecting performance, enabling integration in devices like earbuds, smartwatches, and smartphones, and is compatible with semiconductor and MEMS process technologies for wide-scale commercialization.
Implementation Method 1
The device has an electrode device coupled to the actuator device to initiate movement of the actuator device in a first direction and an electrode on the cap initiating movement in the second direction
Implementation Method 2
the movable diaphragm device has a first surface and a second surface opposite of the first surface configured using the first silicon material to generate a variable pressure to output an acoustic signal
Implementation Method 3
The device has a vented enclosure opposite of the movable diaphragm. In an example, the vented enclosure may have one or more vent openings to allow air to move in and out of the one or more vent openings to generate a sound pressure signal
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 and sensor to track position of the diaphragm. 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 that converts input audio signal in to signal that electrostatically actuates the micro-speaker from one or more surfaces.