In-Plane MEMS Movable Element for High-Frequency Fluid Interaction

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Solution Overview

Problem

Existing MEMS components face challenges in achieving high sound pressure with minimized component surface area while providing a large fluidic effective area for interaction with ambient fluid, and their performance is hindered by spring elements influencing vibration characteristics.

Innovation Solution

A MEMS component design featuring a laterally deflectable element and a passive element connected to a cavity, allowing in-plane movement, which divides the cavity into partial cavities for interaction with ambient fluid, minimizing electrical capacitance and enabling higher accelerations and resonance frequencies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If spring elements are used to connect plates to actuators to accommodate changing geometric dimensions, then the actuators can transmit forces to the plates, but the springs influence the vibration characteristics of the overall system and deteriorate transducer performance

Engineering Contradiction:
Improveaccommodation of changing geometric dimensionsVSAvoidvibration characteristics
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent removes the spring elements from the system entirely. Instead of using springs to connect plates to actuators, the invention uses a rigid cavity structure where the plates are positioned opposite each other within the cavity. The cavity itself accommodates the changing geometric dimensions of the actuators during deflection, eliminating the need for compliant spring connections that would adversely affect vibration characteristics.

Inventive Principle:
Principle #2Taking out (Extraction)

2Area of stationary object

If the component surface area is minimized, then the device size is reduced, but the fluidic effective area for interaction with ambient fluid is limited

Engineering Contradiction:
Improvecomponent surface areaVSAvoidfluidic effective area
Core Design Contradiction:
Area of stationary objectVSArea of moving object

Solution Approach 1:

The patent transitions from out-of-plane deflection to in-plane deflection of the passive element. By moving the passive element laterally within the substrate plane rather than deflecting it vertically, the design achieves a large fluidic effective area for interaction with ambient fluid while maintaining a minimized component surface area footprint. This dimensional change allows the element to sweep through a larger lateral volume.

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

Solution Approach 2:

The passive element is positioned within the cavity formed by the substrate layers, nesting the active and passive elements in a compact configuration. The cavity structure allows both elements to coexist in a minimized surface footprint while the passive element's lateral movement path provides extensive fluidic interaction area.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Quantity of substance

If the passive element has large mass to provide large fluidic interaction volume, then more fluid can be interacted with, but the resonance frequency decreases and acceleration capability is reduced

Engineering Contradiction:
Improvefluidic interaction volumeVSAvoidresonance frequency
Core Design Contradiction:
Quantity of substanceVSSpeed

Solution Approach 1:

The patent employs a lightweight passive element that dynamically interacts with large volumes of ambient fluid through lateral movement. The passive element's small mass enables high resonance frequencies and rapid acceleration, while its lateral deflection path through the cavity allows it to interact with large amounts of fluid. The dynamic lateral motion compensates for the small element mass, achieving both high speed response and large fluidic interaction volume.

Inventive Principle:
Principle #15Dynamics

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 higher resonance frequencies and larger fluidic interaction volumes with reduced electrical capacitance, enhancing performance and interaction with ambient fluid.

Implementation Method 1

The first partial cavity is in contact with an ambient fluid of the MEMS component via at least one first opening. The second partial cavity is in contact with the ambient fluid of the MEMS component via at least one second opening

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Data Source

PatentEP4058400B1MEMS component with in-plane movable element
Publication Date: 2025.09.10 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP4058400B1 patent drawingFigure 1
  • EP4058400B1 patent drawingFigure 2
  • EP4058400B1 patent drawingFigure 3

AI summary

What is proposed is a MEMS component comprising a layer stack comprising at least one second layer formed between a first layer and a third layer. At least one first cavity is formed in the second layer. The MEMS component furthermore comprises a laterally deflectable element having an end connected to a sidewall of the first cavity, and having a free end. Furthermore, the MEMS component comprises a passive element, which is rigidly linked to the free end of the laterally deflectable element, in order to follow a movement of the laterally deflectable element. The laterally deflectable element and the passive element subdivide the first cavity into a first partial cavity and a second partial cavity. The first partial cavity is in contact with an ambient fluid around the MEMS component via at least one first opening. Furthermore, the second partial cavity is in contact with the ambient fluid around the MEMS component via at least one second opening. The at least one first opening is formed in a different layer, chosen from the first layer and the third layer, by comparison with the at least one second opening.