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AssigneeNEC Corporation
InventorsYasuhiro Sasaki, Kaneo Uehara, Takeshi Inoue
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A piezoelectric ceramic transformer comprises a low impedance portion 11 including a plurality of piezoelectric ceramic layers 111 to 115 having different thicknesses, a high impedance portion 12 and internal electrodes 16. The low and high impedance portions 11 and 12 are subjected to a uniform polarization treatment in a thickness direction and with the same vector of polarization. The low impedance portion 11 includes one or more piezoelectric ceramic layers having a thickness different from those of the other layers therein. No delamination of electrodes or breaking of ceramics occur upon polarization treatment. Therefore, a compact piezoelectric ceramic transformer for power source which has a high mechanical quality coefficient Qm and a high electric power transmission efficiency is provided.
A piezoelectric ceramic transformer being driven with a thickness extensional vibration and having a structure in which internal electrodes and piezoelectric ceramic layers are alternately stacked and low and high impedance portions are formed in said stack,
A piezoelectric ceramic transformer being driven with a thickness extensional vibration which comprises a low impedance portion comprising a stack of a plurality of piezoelectric ceramic layers having different thicknesses;
Dependencies are inferred from the claim text.