RU22331U1 - MICROMECHANICAL ACCELEROMETER - Google Patents

Abstract

1. A micromechanical accelerometer containing a housing made in the form of a board made of dielectric material with the stationary electrodes of a capacitive angle sensor and an electrostatic moment sensor deposited on it, an inertial mass made in the form of a silicon plate suspended with a gap on the board in the form of a pendulum on elastic jumpers with supporting elements that form an elastic suspension with a suspension axis lying in the plane of inertial mass, an electronic signal processing circuit, characterized in that the stationary electrodes e Bone angle sensor and the electrostatic torque sensor elementom.2 made uniform. The device according to claim 1, characterized in that the inertial mass, elastic jumpers and supporting elements are made as a single element by anisotropic etching of silicon. The device according to claim 1, characterized in that the silicon wafer is made in the form of a rectangle, on the surface of which through holes are evenly distributed, made in the form of a rectangle, the diagonal of which is not less than twice the initial gap between the inertial mass and the stationary electrodes of the capacitive angle sensor and electrostatic torque sensor.

Description

MICROMECHANICAL ACCELEROMETER

The invention relates to measuring equipment, in particular, to the field of instrumentation and may find application in inertial systems of moving objects, in autopilots of aircraft and ship models, in vehicle safety systems.

A feature of micromechanical accelerometers is the predominant manufacture of sensitive elements of these devices from materials based on silicon technology, which determines: small dimensions and weight of the accelerometer, the possibility of using group manufacturing technology and, therefore, the cheapness of manufacturing in mass production, high reliability in operation.

Known technical solution 1811612 A3, cl. GO1P 15/12, Bull. No. 15, 04/23/93. Electrostatic accelerometer / Malkin Yu.M., Papko A.A., Kalganov V.N., Lyubeznov A.N., Vyatkin S.N., in which the accelerometer contains a housing made in the form of two boards of dielectric material sprayed onto of them with fixed electrodes of a capacitive angle sensor and an electrostatic moment sensor, inertial mass made in the form of a rectangular silicon wafer and suspended with a gap between two boards in the form of a pendulum on elastic jumpers that form an elastic suspension, an electronic signal processing circuit.

The disadvantage of this solution is the complexity of the design and complex manufacturing technology.

Known technical solution Micro-electromechanical instrument and systems development at Draper Laboratory / Harbor N., Connely J., Gilmore J., Greiff P., Kourepenis A., Weinberg M. // 3-nd St. Petersburg International conf. on gyroscopic technology and navigation. May 1996, p. 3-10., Most similar to the proposed invention, in which the pendulum micromechanical accelerometer contains a housing made in the form of a board made of a dielectric material with the fixed electrodes deposited on it by a capacitive angle sensor and an electrostatic moment sensor, an inertial mass filled in the form of a silicon plate suspended with a gap on the board in the form of a pendulum on elastic jumpers with supporting elements that form an elastic suspension with a suspension axis lying in the plane of inertial mass, electronic circuits signal processing.

 5 i 15/08

The disadvantage of this micromechanical accelerometer is its complicated manufacturing technology, as well as its low accuracy, due to the separate implementation of the fixed electrodes of the capacitive angle sensor and electrostatic torque sensor. In addition, the accelerometer has an insufficiently wide range of measurements.

The objective of the present invention is to develop a micromechanical accelerometer, which allows to simplify manufacturing technology, improve accuracy and expand the measurement range.

The technical result was obtained due to the fact that the inertial mass made in the form of a silicon wafer suspended with a gap on the board in a micromechanical accelerometer containing a housing made in the form of a board made of dielectric material with the fixed electrodes of a capacitive angle sensor and an electrostatic torque sensor sprayed on it in the form of a pendulum on elastic bridges with supporting elements that form an elastic suspension with a suspension axis lying in the plane of the inertial mass, an electronic signal processing circuit in, fixed electrodes of the capacitive sensor angle and torque sensor formed electrostatic single element. The inertial mass, elastic bridges and supporting elements can be performed as a single element by the method of anisotropic etching of silicon. The silicon wafer can be made in the form of a rectangle, on the surface of which through holes are evenly distributed, made in the form of a rectangle, the diagonal of which is not less than twice the initial gap between the inertial mass and the stationary electrodes of the capacitive angle sensor and electrostatic torque sensor.

When performing fixed electrodes of a capacitive moment sensor as a single element, a simplification of the manufacturing technology of a micromechanical accelerometer is achieved.

The implementation of the inertial mass, elastic jumpers and supporting elements as a single element by the method of anisotropic etching of silicon also simplify the manufacturing technology of the micromechanical accelerometer.

The through holes provided in the rectangular silicon wafer reduce the etching time of excess silicon and also reduce the consumption of the etchant, which ultimately simplifies the manufacturing technology of the device.

When performing a micromechanical accelerometer, in which the fixed electrodes of the capacitive angle sensor and the electrostatic moment sensor are made by a single element, the accuracy of acceleration measurement is increased and the measurement range is expanded, because the area of fixed electrodes increases. The fixed electrodes of a capacitive angle sensor and an electrostatic moment sensor are sprayed onto a board of dielectric material and form metallized surfaces that simultaneously play the role of stationary electrodes and a capacitive angle sensor and an electrostatic moment sensor.

The list of drawings:

FIG. 1 is a structural diagram of a micromechanical accelerometer;

FIG. 2 - inertial mass with elastic jumpers and supporting elements;

FIG. 3 is an electronic signal processing circuit.

In FIG. 1 shows a structural diagram of an accelerometer;

in FIG. 2 - inertial mass with elastic jumpers and supporting elements;

in FIG. 3 is an electronic signal processing circuit.

The micromechanical accelerometer (Fig. 1) comprises a housing 1 made in the form of a board made of dielectric material. The inertial mass 2 is placed in the housing 1, made in the form of a rectangular silicon wafer, which is suspended in the form of a pendulum on the elastic jumpers 3 with a gap 4 relative to the housing 1. The stationary electrodes 5 of the capacitive angle sensor and the electrostatic torque sensor are sprayed on the housing 1. Elastic jumpers 3 at one end are rigidly attached to supporting elements 6, mounted on the housing 1, and the second to the inertial mass 2 (Fig. 2). The inertial mass 2 is made in the form of a rectangular silicon wafer, on the surface of which through holes 7 of a rectangular shape are evenly distributed (Fig. 2).

The plane of inertial mass 2 (the plane containing the Y-Y, Z-Z axes) is basic, and the elastic bridges 3 form the axis of suspension Z-Z of the inertial mass 2. The elastic bridges 3 provide the possibility of angular movements of the inertial mass 2 of the axis of the suspension Z-Z. The pendulum effect is achieved due to the fact that the center of mass of the inertial mass 2 does not coincide with the suspension axis Z-Z. The sensitivity axis XX is located perpendicular to the base plane of the inertial mass.

The electronic signal processing circuit (Fig. 3) contains a master oscillator 8, fixed electrodes 5 of a capacitive angle sensor and an electrostatic torque sensor, an amplifier 9, a demodulator 10, an inverter 11. The role of the movable electrodes of a capacitive angle sensor and an electrostatic torque sensor is played by an inertial mass 2 of silicon .

The proposed device operates as follows. The voltage from the master oscillator is supplied in antiphase to the stationary electrodes 5. Under the action of acceleration in the direction of the sensitivity axis X-X, the inertial mass 2 deviates from its initial state. In this case, the capacitances C1 and C2 of the differential capacitor formed by the stationary electrodes 5 and the inertial element 2 change. The deviation signal is removed from the inertial element 2 and fed through the capacitor C3 to the amplifier 9, and then to the demodulator 10. The inertial element 2 is supplied with a constant bias UQ for ensure the operation of the electrostatic torque sensor. The output voltage of the demodulator 10 is supplied through the resistor R directly to one stationary electrode 5, and to the other through the inverter 11. The interaction of this voltage with a constant bias voltage UQ leads to the appearance of an electrostatic moment, which tends to return the inertial mass 2 to its original state. In the steady state, the inertia force acting on the inertial mass 2 is balanced by the electrostatic forces of the torque sensor. The voltage at the output of the demodulator 10 is the output signal of the accelerometer.

Thus, the claimed micromechanical accelerometer allows to simplify manufacturing technology, increase accuracy and expand the measurement range.

Claims (3)

1. A micromechanical accelerometer containing a housing made in the form of a board made of dielectric material with the stationary electrodes of a capacitive angle sensor and an electrostatic moment sensor deposited on it, an inertial mass made in the form of a silicon plate suspended with a gap on the board in the form of a pendulum on elastic jumpers with supporting elements that form an elastic suspension with a suspension axis lying in the plane of inertial mass, an electronic signal processing circuit, characterized in that the stationary electrodes e Bone sensor angle and torque sensor formed electrostatic single element.  2. The device according to claim 1, characterized in that the inertial mass, elastic jumpers and supporting elements are made as a single element by anisotropic etching of silicon. 3. The device according to claim 1, characterized in that the silicon wafer is made in the form of a rectangle, on the surface of which through holes are evenly distributed, made in the form of a rectangle, the diagonal of which is not less than twice the initial gap between the inertial mass and the fixed electrodes of the capacitive angle sensor and electrostatic torque sensor.