| 摘要 |
<p>1358168 Piezoelectric transducers PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd 5 Oct 1971 [6 Oct 1970] 46245/71 Heading H4J [Also in Divisions G1 and H1] A piezoelectric element comprises coaxial electrodes 1, 2 defining a space 3 filled with radially polarized powdered ceramic piezoelectric material. The latter may comprise barium titanate with or without addition of lead, or lead titanate/zirconate. The conductors may be made of titanium, copper or nickel. After the space between the conductors has been filled, the assembly is reduced in diameter, e.g. by a factor of about 7, using known mechanical methods. The tubular element obtained in this manner is radially polarized by the "hot" method in which the polarizing voltage is applied as the element cools from a temperature above the Curie point. The finished element may be flexible and is responsive to hydrostatic pressure or to pressure in any radial direction.</p> |
