MEMS Loudspeaker Vertical Sections for Higher Low-Frequency Output
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Solution Overview
Problem
Existing MEMS loudspeakers and microphones face limitations in sound power, particularly at low frequencies, due to the need for large diaphragm areas or excursions, and complex manufacturing processes that hinder miniaturization and efficient sound generation.
Innovation Solution
A MEMS transducer design featuring a vibrating membrane with multiple vertical sections made of actuator material, excited to horizontal vibrations via end electrodes, allowing for high sound power and simplified control without requiring large displacements or complex synchronization of actuators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If planar diaphragm systems with vertical actuation are used, then the manufacturing process is simple, but the sound power is limited especially at low frequencies
Solution Approach 1:
The diaphragm is segmented into multiple vertical sections that can move independently in the lateral direction. This segmentation allows each section to contribute to sound generation, increasing the overall volume flow and sound power while maintaining a compact MEMS structure that is manufacturable using standard processes
Solution Approach 2:
The invention transitions from vertical actuation (single dimension) to lateral vibration (perpendicular dimension). By making the vertical sections vibrate laterally instead of moving vertically, the design increases volume flow capability and sound power, particularly at low frequencies, while maintaining compatibility with MEMS manufacturing
2Power
If large diaphragm areas or excursions are used to achieve sufficient sound power, then sound power increases, but the device size and complexity increase
Solution Approach 1:
Multiple vertical sections are arranged within a compact area, allowing the system to achieve high sound power through coordinated lateral vibration of multiple segments rather than requiring a single large diaphragm. This maintains small device footprint while increasing acoustic output
Solution Approach 2:
The invention changes the motion parameter from vertical excursion to lateral vibration amplitude. By utilizing lateral vibration of vertical sections, the system achieves increased volume flow and sound power without requiring large displacements, thus maintaining compact dimensions
3Ease of operation
If multiple electrostatic bending actuators with gaps are used, then lateral vibration capability is achieved, but ventilation between chambers occurs limiting lower cutoff frequency
Solution Approach 1:
Instead of using gaps between actuators as in prior art, the invention uses continuous vertical sections that vibrate laterally. This inverts the approach by eliminating gaps that cause ventilation, thereby preventing acoustic short circuits and improving lower cutoff frequency while maintaining lateral vibration capability
Solution Approach 2:
The vertical sections are designed as flexible structures that can vibrate laterally. These continuous flexible sections eliminate the need for gaps between rigid actuators, preventing ventilation between chambers while enabling the required lateral motion for sound generation
4Power
If synchronized drive of multiple piezo actuators is used, then lateral movement and sound power are increased, but the control complexity increases
Solution Approach 1:
Multiple vertical sections are electrically connected in parallel and driven by a single electrode pair. This merging of control signals simplifies the drive circuitry while all sections vibrate synchronously in the same direction, maintaining high sound power output without requiring complex synchronized control of multiple independent actuators
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 high sound power and improved sound quality with compact dimensions, simplified manufacturing, and reduced manufacturing costs, while preventing adhesion and dust accumulation, and enabling precise control of vertical sections.
Implementation Method 1
The vertical sections comprise a first layer of an actuator material and a second layer of a mechanical support material
Data Source
Figure 1A~1B
Figure 2A~2D
Figure 2E~2G
AI summary
The invention relates to an MEMS transducer that comprises a vibrating diaphragm (1) for producing or picking up pressure waves in a fluid in a vertical direction, wherein the vibrating diaphragm (1) is held by a support (4) and the vibrating diaphragm (1) has two or more vertical sections (2) that are formed parallel to the vertical direction and comprise at least one layer of an actuator material (11). The ends of the vibrating diaphragm (1) are in contact with an electrode (13), which means that actuation of the at least one electrode (13) allows the two or more vertical sections (2) to be excited to produce horizontal vibrations or which means that excitation of the two or more vertical sections (2) to produce horizontal vibrations results in an electrical signal being able to be generated at the at least one electrode (13).