Contact mode micro accelerometer

Abstract

The invention provides a contact mode micro accelerometer which comprises a lower substrate and an upper substrate. A supporting column, a thin plate, a plurality of supporting beams and anchor pointsof the beams are arranged between the lower substrate and the upper substrate. The lower substrate and the upper substrate are provided with lower and upper fixed electrodes. The surfaces of the fixed electrodes are covered with insulating layers. The upper and lower surfaces of the thin plate are provided with upper and lower moving electrodes. The micro accelerometer has a first working state in which the thin plate and the moving electrodes are deformed by force but are not in contact with the insulating layer and a second working state in which the thin plate and the moving electrodes aredeformed by force and are in contact with the insulating layers. According to the contact mode micro accelerometer, a principle that the accelerometer causes the deformation of the moving electrodesand thus the capacitance between the fixed electrodes is changed is used to work. Through the insulating layers on the fixed electrodes, the short circuit of the moving and fixed electrodes is prevented, the insulating layers provide support for a movable structure, thus the measurement of the high acceleration can be realized, and the capacitance saturation of the sensor can be effectively suppressed by a combined structure of the beams and the round thin plate.

Description

technical field [0001] The invention relates to the field of micro-electromechanical systems, in particular to a contact mode micro-accelerometer. Background technique [0002] Accelerometers are widely used in many fields such as industry, military, aviation, and daily life. According to the working principle, micro accelerometers can be divided into capacitive, piezoresistive, piezoelectric and so on. Among them, the capacitive type has the advantages of low power consumption, fast response, and high sensitivity. Its working principle is: a variable capacitor is composed of a fixed electrode and a moving electrode, and the moving electrode is located on the acceleration sensitive structure and moves due to the acceleration force. The magnitude of the acceleration can be known by measuring the capacitance between the moving and fixed electrodes. Traditionally, the active structure of capacitive micro accelerometers mainly adopts a comb structure or a beam-mass structure c...

AI Technical Summary

Problems solved by technology

In addition, the relative movement between the moving electrode and the insulating layer also leads to the generation of friction force

According to a large number of literatures, including the literature on contact mode micro pressure sensors, van der Waals force and friction can cause significant hysteresis error (return error) to the sensor

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