SU939983A1 - Pressure pickup - Google Patents

Description

(5-) PRESSURE SENSOR

one

The invention relates to a technique for measuring dynamic pressure with a wide range of differential and Can be used in general-purpose static and dynamic pressure recording devices.

Pressure sensors are known which contain a silicon membrane and a strain layer on it. Such a sensor is installed on a dielectric basis with the help of a special adhesive and sealed with fl j.

The lack of sensors is the low sensitivity of the measurement of dynamic pressure due to the stiffness of the connection between the membrane and the dielectric substrate.

The closest in technical essence to the present invention is a device containing a membrane, a dielectric layer placed on it a strain-sensitive layer L l The disadvantage of the device is not high enough sensitivity

measurements at large differential pressure differences, which is associated with a limited change in the magnitude of the impedance of the tensoslo at sudden pressure drops.

The purpose of the invention is to increase the sensitivity of the measurement of dynamic pressure.

The goal is achieved by the fact that a switching dielectric variable mounted on a stress-sensitive layer is inserted into a pressure sensor containing a housing with a membrane on which a stress-sensitive layer with contacts is located

15 TOLTS1INY, a dielectric of the same thickness located on it and control contacts, with dielectrics forming a plate of constant thickness, and between them are installed control

20 contacts.

Claims (1)

FIG. 1 shows the sensor section; in fig. 2 shows section A-A in FIG. 1. The sensor comprises a housing 1 with a membrane 2, on which a shade-sensitive layer 3 with a recording contact and a supply voltage contact 5 is located. Layer 3 has a switching dielectric 6 of variable thickness. Its edge is directed towards the recording contact. On top of the switching dielectric 6 is a dielectric, 7. made of a material with a close-up dynamic expansion coefficient. In dielectric 7, holes 8 can be made in which control contacts 9 are installed. The working pressure P is applied normally to the membrane surface. The pressure sensor operates as follows. Depending on the magnitude of the measured pressure and the required sensitivity, a larger or smaller portion of the stress-sensitive layer is used between the control contacts 9- The magnitude of the sensitivity is controlled by the control voltage and through the contacts 9- When the input voltage Ug increases, the control voltage increases linearly tensioner and. As the voltage U increases, the magnitude of the critical field at contacts 9 reaches a threshold value E- at which dielectric switching 6 occurs. Since the thinnest is the section at the top of dielectric 6 located closest to contact C, then at voltage U the first contact is triggered, the dielectric 6 is switched under this contact to the conducting state. As the control voltage U increases further, the second contact is triggered and, as a result of the switching, the area to the second contact 9 becomes the sensing element, and the sensitivity reaches the next value, etc. Thus, by increasing the voltage U in series, it is possible to control the magnitude of the sensitivity. The magnitude of the control voltage J increases linearly with increasing thickness of the dielectric 6, i.e. determined by its angle and type of switching dielectric. When U dielectric voltage is removed, the dielectric jumps to the initial high resistance state and further, the whole measurement cycle can be repeated (the arrows in Fig. 2 show the current direction lines after switching on the working sections of the stress sensitive layer) to eliminate the nonlinear distortion of the BIN and increase the sensitivity of the dynamic measurement pressure on the switching dielectric 6 is applied to the dielectric 7 close in mechanical characteristics so that the dielectric 6 is compensated by the dielectric on thickness and geometrical parameters Rick 7- In this case, the symmetry conditions are performed vibrating membrane and not non-linear distortion occurs. The holes 8 in the dielectric 7 are formed to accommodate the control contacts 9 on the switching dielectric 6. The technological design of the pressure sensor comprises one or more of these elements. The proposed sensor design makes it possible to significantly increase the limits of adjustment of the sensitivity of dynamic pressure sensors. Claims of pressure sensor, comprising a housing with a membrane on which a stress-sensitive layer with contacts is located, characterized in that, in order to increase the sensitivity of the dynamic pressure measurement, a switching dielectric of the same thickness installed on the stress-sensitive layer is inserted into it and control contacts, with dielectrics forming a plate of constant thickness, with control contacts between them. Sources of information taken into account in the examination 1. USSR author's certificate number 249700, cl. G 01 R, 19692. Author's certificate of the USSR according to application No. 2639977, cl. H01 C 17/00, 1979- (prototype). FIG. FIG. five