US 5,402,031 AGranted

Piezoelectric transformer having improved electrode arrangement

AssigneeNEC Corporation

InventorsSatoru Tagami, Jun Kawai, Akira Fukuoka

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Abstract

A long relatively thin rectangular body of piezoelectric material is divided into driving and driven regions in a longitudinal direction thereof. Two electrodes are applied respectively to two major surfaces of the driving region which is polarized in a thickness direction of the driving region. Another two electrodes are formed on one major surface of the driven region. Each of the two electrodes applied to the driven region has a plurality of finger-like portions which extend in the longitudinal direction. The finger-like portions of formed on the driven region are arranged in an interdigital manner. The driven region has a plurality of regions which are defined by adjacent finger-like portions and which are polarized in a direction perpendicular to the longitudinal direction.

Claims22

Dependent claims

A piezoelectric transformer comprising:

a long relatively thin rectangular body of piezoelectric material, said body exhibiting a resonant mode of vibration at a predetermined frequency in a longitudinal direction of said body, said body being divided into first and second regions in said longitudinal direction;
first and second electrodes applied respectively to first and second major surfaces of said first region, said first region being polarized in a thickness direction of said first region;
and
third and fourth electrodes which are formed on said first major surface of said second region and each of which has a plurality of finger-like portions extending in said longitudinal direction, each of said plurality of finger-like portions of said third electrode having one end electrically coupled to said first electrode, said fourth electrode having a bar portion which extends transversely of said body and from which said plurality of finger-like portions of said fourth electrode extend, said plurality of finger-like portion of said third and fourth electrode being arranged interdigitally, said second region having a plurality of regions which are defined by adjacent finger-like portions of said third and fourth electrodes, each of which is transversely polarized in a direction perpendicular to said longitudinal direction.

1 more element

A piezoelectric transformer comprising a long relatively thin rectangular body of piezoelectric material, said body having first and second major surfaces and exhibiting a resonant mode of vibration at a predetermined frequency in a longitudinal direction of said body, said body being divided into first, second and third regions in said longitudinal direction,

first and second electrodes being applied respectively to said first and second major surfaces of said first region, said first region being polarized in a thickness direction of said first region;
third and fourth electrodes being applied respectively to said first and second major surfaces of said third region, said second region being polarized in a thickness direction of said third region;
fifth and sixth electrodes which are formed on said first major surface of said second region and each of which has a plurality of finger-like portions extending in said longitudinal direction, said fifth electrode being electrically coupled to said first and third electrodes, said sixth electrode having an elongated portion which extends transversely of said body and from which said plurality of finger-like portions of said sixth electrode extend, said plurality of finger-like portions of said third and fourth electrode being arranged interdigitally, said second region having a plurality of regions which are defined by adjacent finger-like portions of said fifth and sixth electrodes, each of which is transversely polarized in a direction perpendicular to said longitudinal direction.

Dependencies are inferred from the claim text.