MEMS with Phase-Offset Openings for Energy Recovery

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Solution Overview

Problem

MEMS-based sound transducers face inefficiencies due to energy dissipation in the back volume and increased installation space, as they typically do not utilize the energy radiated to the back side and require larger space for compression.

Innovation Solution

The design incorporates a substrate with a cavity and movable elements that interact with a fluid, featuring two phase-offset openings to redirect and utilize the energy that would otherwise be dissipated, allowing for smaller MEMS size and efficient energy use by canceling out periodic oscillations and avoiding acoustic short-circuiting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a back volume is used to manage energy from the transducer back side, then energy dissipation is controlled, but installation space increases significantly

Engineering Contradiction:

Improveenergy dissipationVSAvoidinstallation space

Core Design Contradiction:

Loss of energyVSVolume of stationary object

Solution Approach 1:

The patent merges the back volume function with the front volume by connecting both to the same fluidic environment through multiple openings. The first opening connects the front volume to the environment, while the second opening connects the back volume to the same environment, allowing both volumes to interact with the external fluid and eliminating the need for a separate enclosed back volume space

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The transducer is segmented into distinct front and back volumes that can be independently controlled through different openings. This segmentation allows the back volume to be managed separately through the second opening, enabling energy dissipation without requiring a large enclosed back volume space

Inventive Principle:

Principle #1Segmentation

2Loss of energy

If the back volume is used for energy management, then energy control is achieved, but the back volume occupies additional installation space larger than the transducer itself

Engineering Contradiction:

Improveenergy controlVSAvoidback volume space

Core Design Contradiction:

Loss of energyVSVolume of stationary object

Solution Approach 1:

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

Instead of enclosing the back volume to manage energy, the patent inverts the approach by opening the back volume to the environment through the second opening. This allows energy to be dissipated to the external environment rather than being trapped in a closed volume, achieving energy control without requiring enclosed back volume space

Inventive Principle:

Principle #13The other way round (Inversion)

3Loss of energy

If additional energy is used to compress air in the closed back volume, then energy management is achieved, but overall energy efficiency decreases

Engineering Contradiction:

Improveenergy managementVSAvoidenergy efficiency

Core Design Contradiction:

Loss of energyVSUse of energy by moving object

Solution Approach 1:

The patent converts the harmful effect of energy that would be dissipated to the back side into a beneficial resource by directing it through the second opening to the external environment. This allows the energy to be used productively in driving fluid oscillations outside the transducer rather than being wasted in compressing air in a closed volume, improving overall energy efficiency

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 approach enables the creation of compact, energy-efficient MEMS that utilize previously wasted energy, reducing the need for additional space and enhancing the production of periodic oscillations without acoustic short-circuiting.

Implementation Method 1

configured to interact with a fluid arranged in the cavity, wherein a movement of the fluid and a movement of the movable element are causally related

Methodology Applied

Scientific EffectAcoustic oscillation: Sound

Implementation Method 2

a first opening which connects the cavity to an environment of the substrate and which causes a first phase offset of a first periodic oscillation which is causally related to the movement of the movable element when passing through the first opening

Methodology Applied

Scientific EffectPhase offset effect:

Implementation Method 3

a second opening which connects the cavity to the environment of the substrate and which causes a second phase offset, different from the first phase offset, of a second periodic oscillation which is causally related to the movement of the movable element when passing through the second opening

Methodology Applied

Scientific EffectPhase offset effect:

Data Source

PatentUS20240092633A1MEMS, method of manufacturing an MEMS and method of configuring an MEMS

Publication Date: 2024.03.21 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV

AI summary

An MEMS has a substrate and a cavity arranged in the substrate. A movable element is arranged in the cavity, configured to interact with a fluid arranged in the cavity, wherein a movement of the fluid and a movement of the movable element are causally related. A first opening which connects the cavity to an environment of the substrate causes a first phase offset of a first periodic oscillation which is causally related to the movement of the movable element when passing through the first opening. A second opening which connects the cavity to the environment of the substrate causes a second phase offset, different from the first phase offset, of a second periodic oscillation which is causally related to the movement of the movable element when passing through the second opening.