THERMOSTABILISED DISPLACEMENT SENSOR ON SURFACE ACOUSTIC WAVES Russian patent published in 2009 - IPC G01B17/00 G01D3/28 

FIELD: physics; measurement.

SUBSTANCE: present invention pertains to piezoelectric sensors, designed for controlling various physical quantities. The thermostabilised displacement sensor on surface acoustic waves comprises a displacement sensor, comprising two piezoelectric acoustic transmission lines, fixed on two different surfaces, moving relative each other. On the working surfaces of each acoustic transmission line there are interdigital transducers of the same period, the distance between them which, is equal to 200-300 times their periods. The edges of the acoustic transmission line are polished and coated with an acoustic absorber. The device also has a temperature sensor, which is identical to the displacement sensor. Only surfaces on which acoustic transmission lines are fitted do not move and are fixed in such a position such that, the distance between interdigital transducers is equal to 200-300 periods of the interdigital transducers. The interdigital transducer of the displacement sensor is connected to the feedback circuit of an amplifier, forming a generator of electrical oscillations with frequency F₁. The interdigital transducer of the temperature sensor is connected to the feedback circuit of the other amplifier, forming a generator of electrical oscillations with frequency F₂. Signals from both generators are transmitted to a device, giving the frequency ratio of these generators.

EFFECT: increased precision of measurements.

1 dwg