MEMS Loudspeaker Deflection Element Reduces Membrane Stress
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Solution Overview
Problem
Microelectromechanical devices and loudspeakers face challenges in efficiently generating fluid pressure without stiffening the membrane, which can lead to material stress and reduced performance.
Innovation Solution
A microelectromechanical device with a displacement structure featuring a movable membrane and a connection structure that includes a drive element and a deflection element, where the deflection element has lower flexural rigidity than the drive element, allowing for elastic deformation and preventing membrane stiffening, thereby enabling efficient fluid pressure generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a stiff connection structure is used to drive the membrane, then the drive force transmission is improved, but the membrane becomes stiffened and material stress increases
Solution Approach 1:
The connection structure is designed with non-uniform flexural rigidity: the drive element has high flexural rigidity for effective force transmission, while the deflection element has low flexural rigidity to accommodate membrane movement without transmitting stress to the membrane. This local differentiation resolves the contradiction between drive force transmission and membrane stress reduction.
Solution Approach 2:
The deflection element acts as an intermediary between the drive element and the membrane. It transfers the driving force while absorbing the twisting motions through elastic deformation, preventing direct transmission of mechanical stress to the membrane and thus reducing material stress.
2Ease of operation
If a rigid connection structure is used to deflect the membrane, then the deflection control is improved, but the membrane twisting is transferred to the connection structure causing stiffening
Solution Approach 1:
The connection structure incorporates a dynamic deflection element that can elastically deform during membrane operation. This dynamic flexibility allows the structure to adapt to membrane twisting motions rather than imposing rigid constraints, maintaining membrane structural integrity while enabling controlled deflection.
Solution Approach 2:
The flexural rigidity parameter of the connection structure is optimized by making the deflection element more flexible than the drive element. This parameter differentiation allows the deflection element to accommodate membrane twisting through elastic deformation, preventing stress concentration and maintaining membrane integrity.
3Power
If the deflection element has high flexural rigidity, then the drive force transmission is improved, but the membrane twisting cannot be absorbed causing increased stress
Solution Approach 1:
The connection structure employs local quality differentiation with the drive element having high flexural rigidity for effective force transmission and the deflection element having low flexural rigidity to absorb membrane twisting. This spatial differentiation of mechanical properties resolves the contradiction between power transmission and stress reduction.
Solution Approach 2:
The membrane twisting, which would normally be a harmful factor causing stress concentration, is converted into a beneficial effect by designing the deflection element with low flexural rigidity. The twisting motion is absorbed through elastic deformation of the deflection element, transforming a potentially damaging effect into a stress-relieving mechanism.
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 and constant sound pressure over a wide frequency range, reducing harmonic distortion and improving sound quality in microelectromechanical loudspeakers.
Implementation Method 1
the deflection element has a lower flexural rigidity than the drive element and is elastically deformable when the membrane is deflected
Data Source
AI summary
A microelectromechanical device for generating a fluid pressure. The microelectromechanical device includes a displacement structure, wherein the displacement structure has a movable membrane which can be deflected to generate the fluid pressure by means of a drivable connection structure acting on the membrane, and wherein the connection structure has a drive element and a deflection element connecting the membrane to the drive element. The deflection element has a lower flexural rigidity than the drive element and is elastically deformable when the membrane is deflected. A microelectromechanical loudspeaker having such a microelectromechanical device is also described.