MEMS Transducer Volume Flow Interaction
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Solution Overview
Problem
MEMS speakers face challenges in achieving a flat sound pressure curve across frequencies due to miniaturization, with high-quality loudspeakers requiring resonance frequencies below the audible sound range and membrane size being much smaller than sound wavelengths, leading to inefficient sound reproduction, especially for low frequencies.
Innovation Solution
A MEMS transducer with a deformable element that interacts with a volume flow of fluid, integrated with an electronic circuit in a layer stack, allowing for efficient deflection and control of the deformable element using a digital pulse width modulated signal, enabling efficient sound generation and reproduction with minimal space requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the membrane size is reduced for miniaturization, then the device size is reduced, but the sound pressure efficiency deteriorates
Solution Approach 1:
The patent changes the operating parameters by using a deformable element that interacts with volume flow rather than traditional membrane vibration. This allows the miniaturized transducer to achieve efficient sound reproduction by coupling with the acoustic volume flow in the cavity, compensating for the reduced membrane size.
Solution Approach 2:
The patent transitions from two-dimensional membrane vibration to three-dimensional volume flow interaction. The deformable element modulates the volume of the acoustic cavity, creating a volumetric acoustic output that overcomes the limitations of reduced surface area in miniaturized devices.
2Speed
If the membrane stiffness is increased to transmit high frequencies, then the high frequency response is improved, but the deflection amplitude decreases
Solution Approach 1:
The patent changes the mechanical parameters by using a compliance element with optimized stiffness characteristics. The element is designed to provide sufficient restoring force for high frequency response while maintaining adequate deflection amplitude through its specific mechanical design and material selection.
Solution Approach 2:
The patent employs a dynamic compliance element that can adapt its effective stiffness through its mechanical design. The element's geometry and material properties are optimized to provide the right balance between restoring force and deflection amplitude across the audible frequency range.
3Length of moving object
If a very soft diaphragm is used to achieve large deflection, then the deflection amplitude is improved, but the high frequency transmission capability deteriorates
Solution Approach 1:
The patent optimizes the mechanical parameters of the compliance element to achieve the right balance. Through careful selection of material properties, geometry, and structural design, the element provides sufficient stiffness for high frequency response while maintaining adequate compliance for large deflection amplitude.
4Reliability
If the resonance frequency is placed below the audible range for high quality sound, then the sound quality is improved, but the device complexity and size increase
Solution Approach 1:
The patent changes the acoustic parameters by using a compact acoustic cavity with optimized volume and geometry. The cavity is designed to support the necessary acoustic modes for high quality sound reproduction while maintaining a small physical footprint suitable for portable 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 solution allows for high-efficiency sound generation and reproduction, achieving improved sound pressure distribution across frequencies while minimizing space, suitable for portable devices like headphones.
Implementation Method 1
MEMS transducer for interacting with a volume flow rate of a fluid
Implementation Method 2
an electromechanical transducer connected to the substrate in the cavity and having an element deformable in at least one plane of movement
Implementation Method 3
The electronic circuit is connected to the electromechanical transducer and is configured to convert an electrical control signal into a deflection of the deformable element
Data Source
Figure 1
Figure 2a
Figure 2b
AI summary
The invention relates to a MEMS converter for interaction with a volume flow rate of a fluid, the MEMS converter comprising a substrate which has a layer stack with a plurality of layers forming a plurality of substrate planes, and which has a cavity in the layer stack. The MEMS converter comprises an electromechanical converter which is connected to the substrate in the cavity and has an element which can be deformed in at least one plane of movement of the plurality of substrate planes, wherein a deformation of the deformable element in the plane of movement and the volume flow rate of the fluid are causally related. The MEMS converter comprises an electronic circuit which is located in a layer of the layer stack, wherein the electronic circuit is connected to the electromechanical converter and is designed to provide a conversion between a deformation of the deformable element and an electric signal.