A medium insertion type capacitive pressure sensor and preparation method thereof

Abstract

The invention belongs to the field of pressure sensors, and more particularly, relates to a medium insertion type capacitive pressure sensor and a preparation method thereof. The medium-insertion capacitive pressure sensor includes a base body, a support layer and a pressure-sensitive layer. The base body includes a substrate and a comb-shaped electrode. The pressure-sensitive layer includes an elastic film and a pressure-sensitive array connected to it under the elastic film. The array unit of the array is just above the comb-shaped electrode comb-tooth gap, and the elastic film, the substrate and the support layer form a closed vacuum cavity structure, so that the elastic film drives the pressure-sensitive array to move downward under the action of pressure. The position of the comb-shaped electrode is fixed, so that the pressure-sensitive array is inserted between the two electrode plates of the parallel-plate capacitor of the comb-tooth electrode, changing the relative permittivity of the dielectric between the electrode plates, thereby causing the capacitance to change, and then by detecting the capacitance The pressure can be measured. The capacitive pressure sensor can increase its sensitivity while increasing linearity.

Description

technical field [0001] The invention belongs to the field of pressure sensors, and more particularly, relates to a medium insertion type capacitive pressure sensor and a preparation method thereof. Background technique [0002] Pressure sensors based on MEMS technology are widely used in many fields such as industrial production, medical care, environmental monitoring, and scientific research. Among them, capacitive pressure sensor is a main type of MEMS pressure sensor, and its fundamental principle is to convert pressure changes into capacitance changes. According to the capacitance calculation formula: where ε 0 is the vacuum dielectric constant, which is a fixed value; ε r is the relative permittivity, which is the equivalent relative permittivity of the dielectric between the capacitor electrode plates; A is the facing area of ​​the capacitor electrode plates; d is the distance between the capacitor electrode plates. Existing capacitive pressure sensors generally c...

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Problems solved by technology

[0006] Aiming at the defects or improvement needs of the prior art, the present invention provides a medium-inserted capacitive pressure sensor and its preparation method. By redesigning the structure of the capacitive pressure sensor, a new working principle is provided. Capacitive pressure sensor, the pressure sensor can change the relative permittivity ε between the capacitive plates r To change the output capacitance value; the simulation of the pressure sensor working in the large deflection deformation area shows that not only the sensitivity is greatly improved, but also the linearity is greatly improved, and finally the high sensitivity is obtained. At the same time, high linearity can be obtained, which solves the technical problem that the linearity and sensitivity of capacitive pressure sensors in the prior art are mutually restricted and cannot be taken into account.

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