Vertical MEMS Transducer Membrane Corrugations
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Solution Overview
Problem
Current MEMS loudspeakers face limitations in sound power, particularly at low frequencies, due to the need for large deflections or large-area membranes, which are difficult to achieve with MEMS technology, and suffer from ventilation issues and limited sound power due to lateral movement constraints.
Innovation Solution
A MEMS transducer with an oscillatable membrane having vertical sections parallel to the emission direction, excited to horizontal oscillations by an electrode, featuring corrugations and/or weakened areas to enhance deflectability and reduce rigidity, allowing for increased sound pressure and audio quality without requiring large deflections or areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If large deflections or large-area membranes are used to achieve sufficient sound power, then sound pressure level increases, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The membrane is divided into multiple vertical sections that can oscillate independently or in coordination. This segmentation allows the system to achieve high sound power through collective motion of multiple smaller elements rather than requiring a single large membrane, thereby reducing manufacturing complexity while maintaining acoustic performance
Solution Approach 2:
The patent transitions from conventional planar membrane oscillation to three-dimensional vertical sections that oscillate horizontally. This dimensional change enables the membrane structure to displace larger volumes of air without increasing the membrane's planar area, achieving high sound power within compact MEMS dimensions
2Power
If lateral movement of bending actuators is increased to improve sound power, then volume flow increases, but pull-in effect and acoustic breakdown occur
Solution Approach 1:
Instead of moving the membrane laterally to generate sound, the patent inverts the approach by having vertical sections oscillate horizontally while maintaining their vertical orientation. This inversion allows large volume displacement without the lateral bending actuators experiencing pull-in effects, as the motion is perpendicular to the actuator's bending plane
Solution Approach 2:
The membrane is designed as a flexible structure with vertical sections that can oscillate horizontally. The flexibility of the membrane allows these sections to achieve large horizontal excursions without structural failure, enabling high sound power output while maintaining reliability through controlled elastic deformation
3Ease of operation
If gaps between bending actuators and cover/bottom wafers are created for mobility, then lateral movement is enabled, but ventilation between chambers occurs
Solution Approach 1:
The patent extracts the mobility function from lateral bending actuator movement and relocates it to horizontal oscillation of vertical sections. This extraction eliminates the need for gaps between actuators and wafer surfaces, thereby preventing ventilation between chambers while preserving the mobility required for sound generation
Solution Approach 2:
The patent replaces the mechanical bending actuator system with an electrostatic actuation system that generates horizontal oscillations of vertical sections. This substitution eliminates the mechanical gaps required for bending actuator mobility, preventing harmful ventilation while maintaining the ability to generate sound through controlled horizontal motion
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 acoustic power with simplified control and reduced manufacturing effort, enabling efficient horizontal vibrations that increase sound pressure levels and audio quality, while minimizing distortion and harmonics.
Implementation Method 1
an oscillatable membrane for generating or absorbing pressure waves in a vertical emission direction
Implementation Method 2
the oscillatable membrane having vertical sections which are essentially parallel to the Emission direction or recording direction are formed and comprise at least one layer of an actuator material. The oscillatable membrane is preferably in contact with an electrode at the end, so that the vertical sections can be excited to horizontal oscillations by controlling the electrode
Data Source
Figure 1a~1b
Figure 2a~2c
Figure 2d~2f
AI summary
In a first aspect, the invention relates to a MEMS transducer comprising a vibrating diaphragm for generating or receiving pressure waves in a vertical emission direction. The vibrating diaphragm is held by a support and has vertical sections that are substantially parallel to the emission or reception direction and comprise at least one layer of an actuator material. The vibrating diaphragm is preferably end-contacted with an electrode, such that the vertical sections can be excited to horizontal vibrations by controlling the electrode, or an electrical signal can be generated at the electrode when the vertical sections are excited to horizontal vibrations. The vertical and/or horizontal sections have one or more corrugations and/or attenuation zones.In another aspect, the invention relates to a method for manufacturing the MEMS transducer according to the invention.