Hoechst Ceramtec Aktiengesellschaft

Hoerbiger Fluidtechnik Kg

Thomas Uhl

Herbert Frisch

Kurt Handschuh

Heinrich Berthold

Georg Wiesend

To produce a piezoelectric tone generator, a layer of filler-free bonding agent whose dynamic viscosity is 800 to 18,000 mPa.multidot.s is applied between a metallized carrier plate and a piezoceramic wafer. The package composed of carrier plate, bonding layer and ceramic plate is pressed together, the quantity of bonding agent being chosen to be so large that during pressing a bead covering the edge of the ceramic wafer is formed. The bonding layer is cured thereafter, firstly catalytically or thermally and then by UV irradiation.

Piezoelectric tone generator and a process for producing it

A piezoelectric bending transducer is described which is suitable for installation in a valve channel. It is composed of at least one ceramic layer which is metalized on both sides and has piezoelectric properties and which is polarized such that on application of a voltage it undergoes a change in length, and of at least one rigid molding which is joined to the whole surface thereof and has approximately the same surface dimensions and which on application of a voltage does not undergo an elongation or undergoes an opposite elongation. The piezoceramic layer contains an unmetallized area which has a roughness R.sub.a of less the 0.5 .mu.m and covers an orifice in the valve channel.

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Selb, Germany

Thomas Uhl