PIEZOELECTRIC MICROMOVEMENT ACTUATOR AND FORCE SENSOR HYBRIDIZATION USING A THICK-FILM DOUBLE-PASTE PRINTING METHOD

This paper describes the fabrication and characteristics of a new type of low-voltage ( < 40 V) piezoelectric Pb0.97Nd0.02(Ti0.45Zr0.55)O3 m ultilayer actuator/force sensor. Thick-film hybrid technology is used in a wide spectrum of applications with new areas being continually di scovered. In the manufacture of solid-state sensors and actuators, how ever, these applications require special modifications to normal print ing conditions. A thick-film hybrid, combining a PZT low-voltage multi layer micromovement actuator and a force sensor, has been realized usi ng a specially developed double-paste printing (DPP) method. The trans ducer structure is capable of working in pressure-sensing applications where two clamped opposing surfaces are subjected to a static force l oading. A decrease in capacitor voltage under static force conditions (a problem of the leakage current) is avoided by implementing a small force-inducing dynamic displacement (10-100 nm) multilayer (six layers , layer thickness 40 mum) actuator, vibrating at a frequency >10 Hz, i nto the same multilayer element. The sensitivity (effective voltage) o f the prototype transducer is almost-equal-to 1 mV/N (almost-equal-to 0.35 mV/bar) (for 2.4 mm diameter, In(acteff) (sinusoidal) = 40 V and displacement almost-equal-to 100 nm). The suitable actuating frequency range is between 10 and 200 Hz, and the measurement range is 400 bar (20 kg loading mass). The sensitivity can be adjusted by changing the structure of the transducer.