HIGH-FREQUENCY THIN-FILM CAPACITIVE PRESSURE SENSOR Russian patent published in 2019 - IPC G01L9/12 

FIELD: measuring equipment.

SUBSTANCE: use to create a capacitive pressure sensor. Invention consists in the fact that a high-frequency thin-film capacitive pressure sensor consists of four dielectric films, the main screen is formed on the surface of the first dielectric film, first side screen is formed on the upper surface of the second dielectric film; the first dielectric film is the insulator between the main screen and the object of study, combined facing (membrane) is formed on the bottom surface of the fourth dielectric film; at least five through support holes pass through the first, second dielectric films and response plates to connect the sensor cavity under the membrane with atmospheric pressure; sensor is fixed on the surface of the object of study through the first dielectric film with grooves to maintain communication of the cell with the atmosphere through the support holes, while on the surface of the second dielectric film formed response plates of metal foil of rectangular or round shape; diameter of the perforation cell is chosen equal to 2a, where a – is the radius of the perforation cell, the height l of the perforation cell is chosen equal to the height of the total membrane thickness l₁, to maintain a linear relationship between the output and input parameters, the membrane deflection is chosen much less than the total thickness l/2; after forming the sensor membrane from a dielectric film, the thickness of the metallized layer t is chosen to be no more than one micron, otherwise, when the membrane is a metal film, its thickness t is chosen in the range from 2 microns to 40 microns, at that the same time ensuring the minimum level of the measured pressure from 1 Pa to 20 kPa; maximum – from 200 Pa to 1,100 kPa, moreover, if the membrane is formed from a polyimide film, frequency of its own oscillations is 4.5 times lower than the magnitude of the natural frequency of a nickel film; moreover, the polyimide film selected as insulation and for metal coating in vacuum should be not less than 10 microns thick.

EFFECT: providing the possibility of expanding the frequency range of thin-film capacitive sensors more audio frequency (from 20 Hz to 20 kHz).

1 cl, 4 dwg