Design and Implementation of a Novel Skull Vibration Sensing Module for Bone Conduction Microphone

Abstract

This study presents a packaged MEMS acoustic or air pressure sensing module (Fig. 1) to detect the skull vibration for bone conduction microphone (BCM) application. The proposed microphone design has two merits: (1) the packaged module (Fig. 1) enable the skull vibration detection using the MEMS sensor; (2) no sound port is required to remove the environmental and wind noise and to avoid the damage from dust and water (Fig. 1a). The device with the dimensions of 3.5times 2.65times 1.48 text{mm}-{3} is implemented using the packaging and assembly of existing MEMS sensor with polymer diaphragm and metal proof-mass. Measurements show the device has a sensitivity of -39.1dB/g, text{THD} < 0.22 % at 1kHz, and ±5dB bandwidth for 100Hz∼6.7kHz. Frequency responses of different samples show good repeatability.