Capacitive acceleration sensor with acoustic cavity

Abstract

The invention provides a capacitive acceleration sensor with an acoustic cavity, comprising a sensor frame, an acceleration detection structure composed of a detection quality block and an elastic vibrating diaphragm, and a back plate with damping holes and limit embosses, wherein, the detection quality block is arranged at the center of the acceleration sensor and is connected with the sensor frame by the surrounding elastic vibrating diaphragm; the damping holes manufactured on the back plate are used for adjusting system damping, and the limit embosses are used for preventing adhesion or damage in the case of overload; the detection quality block is parallel to the back plate, and detection capacitances are respectively formed on the opposite surfaces of the detection quality block andthe back plate; and the fact that the sensor frame is internally provided with an acceleration detection structure and internally formed with the acoustic cavity after the back plate is closed can improve frequency response. The sensor structure of the invention has lower requirement on the vacuum degree of the acceleration sensor, and can adjust important parameters such as a quality factor Q and the like which can adjust a system by changing density and size of the damping holes and volume of the acoustic cavity and the like, thus realizing larger flexibility on design and manufacture.

Description

technical field [0001] The invention relates to the technical field of inertial sensors, in particular, the invention relates to a novel capacitive acceleration sensor structure with an acoustic cavity. Background technique [0002] Acceleration sensor is a very important inertial sensing and measurement device, which is widely used in aerospace, vibration monitoring, industrial control, geophysical exploration and other fields. In recent years, with the development and maturity of MEMS (micro-electromechanical systems) technology, MEMS acceleration sensors have been widely used in automotive electronics and consumer electronics products due to their small size, light weight, low cost, and high integration. And further expand to the field of industrial application, has a broad market prospect. [0003] The acceleration sensor realizes the measurement of the external acceleration by converting the sensed acceleration into an electrical signal output at a certain ratio. Acco...

AI Technical Summary

Problems solved by technology

Although these two structures have commercial products, they have high requirements on the vacuum degree in the device, and the mass block is relatively small. The quality factor Q of the system often depends on the vacuum degree inside the acceleration, which often limits the vacuum degree in other aspects. Applications

Moreover, in the above two structures, there is a closed space between the two plates of the detection capacitor. When the detection mass moves, the gas in this space cannot flow to other places and can only be compressed. The damping caused by the gas in the system is large, and the elastic behavior It is also more complicated, and the Q value can only be adjusted by adjusting the vacuum degree of the gas in the confined space.

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