MEMS Loudspeaker Barrier Plate for Ultrasonic Wave Demodulation
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Solution Overview
Problem
Existing MEMS loudspeakers suffer from low sound wave demodulation efficiency, low amplitude, and poor acoustic performance due to the narrow gap between the baffle plate and supporting structure, leading to distortion of symmetrical ultrasonic waves.
Innovation Solution
The MEMS loudspeaker design includes a supporting structure, diaphragm, and barrier plate with a specific distance and damping holes to demodulate amplitude-modulated ultrasonic waves into modulated sound waves, utilizing piezoelectric, electrostatic, or electromagnetic driving, and materials like monocrystalline silicon, metal, or polymer barrier plates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a narrow gap is formed between the baffle plate and supporting member, then the structure is compact, but the symmetrical ultrasonic waves are distorted and demodulation efficiency is low
Solution Approach 1:
The patent introduces a barrier plate that creates asymmetric interaction with the diaphragm vibration, converting symmetric ultrasonic waves into asymmetric sound waves. This asymmetry enables effective demodulation of audible sound from the ultrasonic carrier wave, resolving the demodulation efficiency problem while maintaining compact structure.
Solution Approach 2:
The barrier plate acts as an intermediary element between the diaphragm and the external environment. It mediates the interaction by providing a controlled asymmetric boundary that facilitates wave demodulation without requiring a large gap, thus maintaining compactness while improving demodulation efficiency.
2Stability of the object's composition
If the diaphragm vibrates with low amplitude, then the structure is stable, but the acoustic performance is poor
Solution Approach 1:
The patent utilizes mechanical vibration resonance by optimizing the diaphragm's vibrational characteristics. The barrier plate's asymmetric interaction enhances the vibration amplitude at audible frequencies through demodulation, improving acoustic performance while the diaphragm maintains stable operation at ultrasonic frequencies.
Solution Approach 2:
The patent changes the vibrational parameters by introducing the barrier plate, which modifies the acoustic field and enables amplitude modulation demodulation. This allows the system to achieve high acoustic output from low-amplitude diaphragm vibrations by exploiting the nonlinear interaction with the barrier plate.
3Device complexity
If symmetrical ultrasonic waves are used, then the driving is simple, but the waves cannot be effectively demodulated into audible sound
Solution Approach 1:
The barrier plate introduces asymmetry into the system, causing the symmetric ultrasonic waves to interact asymmetrically with the barrier. This asymmetric interaction generates the necessary conditions for demodulation, allowing simple symmetric driving to produce asymmetric demodulated output without complex modulation circuits.
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
Improves sound wave demodulation efficiency and amplitude, enhancing acoustic performance by converting symmetric ultrasonic waves into asymmetric sound waves through the barrier plate's distance and damping holes configuration.
Implementation Method 1
a driving mode for the diaphragm is any one of piezoelectric driving, electrostatic driving, and electromagnetic driving
Implementation Method 2
a driving mode for the diaphragm is any one of piezoelectric driving, electrostatic driving, and electromagnetic driving
Implementation Method 3
a driving mode for the diaphragm is any one of piezoelectric driving, electrostatic driving, and electromagnetic driving
Implementation Method 4
due to the distance between the barrier plate and the diaphragm, the amplitude-modulated ultrasonic waves are demodulated to obtain modulated sound waves
Implementation Method 5
a plurality of damping holes penetrating through the diaphragm and/or the barrier plate are provided in the diaphragm and/or the barrier plate in a spacing manner in a vibration direction of the diaphragm
Data Source
AI summary
The present invention discloses a micro-electromechanical system (MEMS) loudspeaker, which includes a supporting structure, a diaphragm and a barrier plate. The supporting structure includes a supporting body and a sound hole penetrating from one end of the supporting body to the other end. The diaphragm is fixed on an inner circumferential side of the supporting body and located in the sound hole. The diaphragm is configured to vibrate and generate amplitude-modulated ultrasonic waves. The barrier plate is covered and fixed to one end of the supporting body. Due to the distance between the barrier plate and the diaphragm, the amplitude-modulated ultrasonic waves are demodulated to obtain modulated sound waves. Thereby improving the sound wave demodulation efficiency and amplitude of the MEMS loudspeaker and further improving the acoustic performance of the MEMS loudspeaker.