MEMS Speaker Series Sound Generator and Amplifier
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Solution Overview
Problem
Existing MEMS loudspeakers require a large construction volume to achieve significant sound pressure levels, limiting their compactness and acoustic performance.
Innovation Solution
A MEMS loudspeaker arrangement with two MEMS loudspeakers arranged in series, where one acts as a sound generator and the other as an amplifier, guided through a common sound duct to increase sound pressure levels while maintaining a compact design, utilizing a control unit to optimize sound wave superimposition and interference for enhanced acoustic performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If a single MEMS loudspeaker is used, then the construction volume can be kept small, but the sound pressure level is insufficient
Solution Approach 1:
The system divides the sound generation function into two separate MEMS loudspeakers: one dedicated to generating sound waves and another dedicated to amplifying them. This segmentation allows each component to be optimized for its specific function while working together to achieve high sound pressure levels in a compact configuration.
Solution Approach 2:
The patent arranges the MEMS loudspeakers in a nested or series configuration where the sound waves generated by the first loudspeaker pass through and are amplified by the second loudspeaker. This nesting approach maximizes the acoustic output within a minimized construction volume.
2Stress or pressure
If multiple MEMS loudspeakers are arranged in parallel, then the sound pressure level can be increased, but the device complexity increases
Solution Approach 1:
Instead of using multiple loudspeakers in parallel, the system segments the function into sequential roles (generator vs. amplifier) arranged in series. This reduces the complexity of interconnections and control while achieving the same sound pressure enhancement through a simpler linear arrangement.
Solution Approach 2:
The second MEMS loudspeaker serves a dual purpose: it acts as a sound generator like the first, but additionally functions as an amplifier for the waves generated by the first loudspeaker. This multi-functionality reduces the total number of components needed while maintaining high sound pressure output.
3Stress or pressure
If the sound duct is made longer to guide sound waves, then the sound pressure can be increased through amplification, but the construction volume increases
Solution Approach 1:
The sound duct is designed with a nested or folded configuration that allows the sound waves to traverse an effective longer path for amplification purposes while maintaining a compact external footprint. The duct may fold back on itself or use three-dimensional routing to achieve the required acoustic path length without increasing the overall device dimensions.
Solution Approach 2:
Instead of extending the sound duct linearly in one dimension, the patent utilizes three-dimensional space by routing the duct through multiple levels or directions. This allows the sound waves to travel a longer effective path while the external dimensions of the device remain compact.
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 configuration increases sound pressure and volume while minimizing the construction volume, resulting in a compact MEMS loudspeaker arrangement with improved acoustic performance through constructive interference and controlled sound wave amplification.
Implementation Method 1
a sound generator for generating an initial wave
Implementation Method 2
the two MEMS loudspeakers can be controlled in such a way that the first of the at least two MEMS loudspeakers - i.e. the MEMS loudspeaker whose sound waves travel the longer path to the common Sound outlet opening have to cover - as a sound generator for generating an initial wave and the second MEMS loudspeaker downstream from this - i.e. the MEMS loudspeaker whose sound waves have to travel a shorter distance to the sound outlet opening compared to the first MEMS loudspeaker - is designed as a sound amplifier for amplifying this initial wave
Data Source
Figure 1~2a
Figure 2b~2c
AI summary
The invention relates to a MEMS loudspeaker arrangement (1) for generating sound waves in the audible wavelength spectrum, comprising a housing (2), which has a sound conduction channel (8) and a sound outlet opening (10) arranged at the end of said sound conduction channel (8), at least two MEMS loudspeakers (3) which are arranged in the housing (2) such that the sound waves generated by the MEMS loudspeakers (3) can be conducted to the common sound outlet opening (10) via the common sound conduction channel (8), and a control unit for controlling the MEMS loudspeakers (3). According to the invention, one of the two MEMS loudspeakers (3) is arranged downstream of the other in the direction of the sound outlet opening (10). The control unit is further designed such that, in order to increase the maximum sound intensity of the MEMS loudspeaker arrangement (1), the two MEMS loudspeakers (3) can be controlled such that the first of the two MEMS loudspeakers (3) is designed as a sound generator (12) for generating an initial wave (15) and the second MEMS loudspeaker (3) arranged downstream thereof as a sound amplifier (13) for amplifying said initial wave (15).