A Highly Sensitive Vibration Sensor

Abstract

The invention discloses a high-sensitivity vibration sensor, and the sensor comprises a substrate with a cavity and a plurality of piezoelectric cantilever beams; a fixed column is arranged in the center of the bottom surface of the cavity, and a signal receiving area is defined by the plurality of cantilever beams and is fixed above the substrate through the fixed column; each piezoelectric cantilever beam comprises a fixed end and a free end, wherein the width of the free end is greater than that of the fixed end, the fixed end is fixed to the fixed column, the free end is suspended above the cavity, and a gap is formed between every two adjacent piezoelectric cantilever beams. The sensor further comprises a sealing cap with a groove, and the groove edge of the sealing cap is connected with the free end of each piezoelectric cantilever beam. The section of the groove can be in any shape, and a trapezoid with the included angle between the bottom face and the side wall greater than 90degrees is preferably selected. According to the invention, a load generated by a vibration signal is concentrated at the free ends of the piezoelectric cantilever beams through the sealing cap, so the bending moment borne by the piezoelectric cantilever beams is larger, the deflection degree of the piezoelectric cantilever beams is larger, a larger transverse load can be generated when the included angle is greater than 90 degrees, and the sensitivity of the vibration sensor is effectively improved.

Description

technical field [0001] The invention relates to the field of MEMS piezoelectric devices, in particular to a high-sensitivity vibration sensor. Background technique [0002] Vibration widely exists in nature, industry and human life. Different vibrations transmit various signals, such as air vibration, machine equipment vibration, water flow and geological vibration. Obtaining the information carried in vibration requires the help of various vibration sensors, which are widely used in many fields such as energy, chemical industry, medicine, automobile, metallurgy, machine manufacturing, military industry, scientific research and teaching. Such as reading the sound signal transmitted by air vibration through the microphone; the accelerometer is used to measure the acceleration of the vibrating object; the ultrasonic detector detects and analyzes the vibration signal of the mechanical equipment to judge the degree of deterioration of the machinery itself and predict its life; t...

AI Technical Summary

Problems solved by technology

However, the existing piezoelectric vibration sensor structure has limited response to vibration signals, the output electrical signal of the sensor is small, and the sensitivity is low

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