MEMS Transducer Valve Structure for Efficient Volume Flow Interaction

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Solution Overview

Problem

MEMS transducers, particularly MEMS speakers, face challenges in achieving efficient interaction with fluid volume flows due to limitations in membrane deflection, stiffness, and integration complexity, leading to suboptimal sound pressure distribution across frequencies.

Innovation Solution

A MEMS transducer design featuring a deformable element that moves laterally, allowing for efficient interaction with fluid volume flows while maintaining a small chip surface area, enabling high-efficiency operation in MEMS speakers, microphones, and pumps.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a conventional membrane structure is used for MEMS transducer, then the device can be manufactured with standard processes, but the efficiency of interaction with volume flow is insufficient

Engineering Contradiction:
Improveefficiency of interaction with volume flowVSAvoidchip surface dimensions
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent transitions from a conventional two-dimensional membrane structure to a three-dimensional deformable element that bends within the chip plane. This allows the element to interact with volume flow efficiently while maintaining a compact chip footprint, as the deformation occurs in the third dimension (vertical bending) rather than requiring large lateral movements.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent employs a dynamically deformable element that can change its shape in response to volume flow. The deformable element bends dynamically to convert volume flow into mechanical motion, enabling efficient interaction with fluid flow while maintaining a compact static footprint on the chip.

Inventive Principle:
Principle #15Dynamics

2Productivity

If the deformable element is made more compliant to increase deformation, then the interaction efficiency improves, but the structural stability deteriorates

Engineering Contradiction:
Improveinteraction efficiencyVSAvoidstructural stability
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The patent implements different stiffness characteristics in different regions of the deformable element. The element has a base region with higher stiffness for structural stability and a tip region with lower stiffness for enhanced deformation. This local variation in mechanical properties allows the element to maintain overall stability while achieving sufficient deformation for efficient volume flow interaction.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The deformable element is constructed from composite materials or layered structures that combine materials with different mechanical properties. This allows the element to exhibit both stable structural characteristics and compliant deformation regions, resolving the contradiction between stability and deformability.

Inventive Principle:
Principle #40Composite materials

3Area of stationary object

If the chip surface area is reduced for miniaturization, then the device compactness improves, but the interaction area with volume flow is reduced

Engineering Contradiction:
Improvechip surface areaVSAvoidvolume flow interaction capability
Core Design Contradiction:
Area of stationary objectVSProductivity

Solution Approach 1:

The patent utilizes the vertical dimension (third dimension) for the deformable element's operation. By bending vertically within the chip plane rather than requiring lateral expansion, the element achieves sufficient interaction area with volume flow while maintaining a compact chip footprint. The deformation amplitude occurs in the vertical direction, effectively utilizing space without increasing chip surface area.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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

This design enhances the efficiency and acoustic performance of MEMS transducers by allowing large areas to interact with fluid flows, achieving high sound levels and sensitivity with reduced parasitic vibrations and increased mechanical stability.

Implementation Method 1

an electromechanical converter connected to the substrate and having an element which is deformable along a lateral direction of movement

Methodology Applied
Scientific EffectElectromechanical conversion: Electromagnetic Induction

Implementation Method 2

The proposed solution enables high-efficiency interaction with volume flows, allowing for efficient fluid transport and acoustic sound wave generation

Methodology Applied
Scientific EffectAcoustic generation through vibration: Vibration

Data Source

PatentEP3878801A1MEMS transducer for interacting with a volume flow of a fluid and method of manufacturing the same
Publication Date: 2021.09.15 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP3878801A1 patent drawingFigure 1
  • EP3878801A1 patent drawingFigure 2A
  • EP3878801A1 patent drawingFigure 2B

AI summary

A MEMS transducer for interacting with a volumetric flow of fluid comprises a substrate having a cavity; and an electromechanical transducer connected to the substrate within the cavity, which has an element deformable along a lateral direction of motion, wherein deformation of the deformable element in-plane along the lateral direction of motion and the volumetric flow of the fluid are causally related. The cavity has an opening in the substrate, wherein a valve structure is arranged in a region of the opening, configured to reduce the flow of the volumetric flow through the opening in at least one direction out of and/or into the cavity.