MEMS Microphone Diaphragm Hardness Control via Voltage

The patent applies the dynamics principle by making the diaphragm's mechanical properties adjustable through electrical voltage. The displacement adjusting layer changes the stiffness of the diaphragm dynamically based on applied voltage, allowing the microphone to adapt its sensitivity characteristics. This enables the system to optimize performance for different sound pressure levels, resolving the contradiction between detecting low sounds and handling loud sounds.

The patent implements parameter changes by modifying the physical state of the diaphragm through voltage application. The displacement adjusting layer alters the stiffness parameter of the diaphragm based on electrical input, which directly changes the mechanical resonance and sensitivity characteristics. This allows the microphone to transition between high-sensitivity mode for quiet sounds and low-sensitivity mode for loud sounds, expanding the acoustic pressure measurement range.

The same dynamics principle works in reverse to address this contradiction. By adjusting the voltage applied to the displacement adjusting layer, the system can reduce diaphragm stiffness to increase the acoustic overload point for loud sound detection, or increase stiffness to improve sensitivity for low sound detection. This dynamic adjustment capability allows the microphone to adapt to different acoustic environments.

The parameter changes principle is applied by using voltage to modify the stiffness parameter of the diaphragm. When higher voltage is applied, the diaphragm becomes stiffer, increasing the acoustic overload point for loud sound detection. When lower voltage is applied, the diaphragm becomes more compliant, improving sensitivity for low sound detection. This electrical control of mechanical parameters resolves the trade-off between these two performance aspects.