Tokin Corporation

Yoshiaki Fuda

Masafumi Katsuno

Katsunori Kumasaka

Tetsuo Yoshida

Tomeji Ohno

Koichi Okamoto

Naoki Wako

Yoshihiro Ino

Hutoshi Shiotani

A piezoelectric transformer (,) comprises a piezoelectric rectangular body (,) equally divided into first to fourth regions (A,, A,, A,, and A,) in a longitudinal direction. The first and the fourth regions (A,, A,) are provided with plane electrodes (,and,) as input electrodes and polarized in a thickness direction. Strip-like electrodes (,) are formed at the boundary between the remaining second and third regions (A,A,) as output electrodes. An AC input voltage having a frequency corresponding to a wavelength equal to a half of the length of the piezoelectric rectangular body is applied to the input electrodes to vibrate the piezoelectric plate in a two-wavelength resonance mode. A voltage produced by a piezoelectric effect in response to the vibration is extracted from an output terminal. The transformer is small in size, low in vibration rate and heat generation, and excellent in efficiency. As a modification, the input electrodes may be formed in two or three regions which are opposite to each other in displacement distribution in the two-wavelength resonance without being restricted to the first and the fourth regions while the output electrode is provided in another region.

Piezoelectric transformer

A piezoelectric transformer element is wrapped together with primary lead members and secondary lead members by a thin soft insulating sheet, with the primary and secondary lead members being exposed outside the wrapping sheet, so that the transformer element is small in size, and easy in handling, and mounting operation on a circuit board. The primary and secondary lead members can be formed of a flexible flat cable. In an electric power supply device using the piezoelectric transformer element, the transformer element, and the flexible flat cable are wrapped by the wrapping sheet together with a portion of a circuit board on which the transformer element and other circuit elements are mounted.

Piezoelectric transformer wrapped by wrapping member of soft insulating

A piezoelectric transformer comprising a rectangular plate of a piezoelectric material which is polarized in a thickness direction in a first half section of the plate in a longitudinal direction but is polarized in a width direction in a second half section of the remaining half section. A pair of primary electrodes are coated on the upper and the lower surfaces of the first half section and a pair of secondary electrodes are coated on the opposite side surfaces of the second half section, in an alternative structure, the plate is polarized in the thickness direction in opposite end sections of the plate having a size one third of length of the plate and polarized in width direction at the remaining middle section of plate between opposite end sections. The pair of primary electrodes formed on upper and lower surfaces of opposite end sections of plate and pair of secondary electrodes formed on opposite side surfaces of middle section. The pair of secondary electrodes may be deposited on upper or lower surfaces adjacent opposite side edges. In a voltage converter using the piezoelectric transformer, a pulse generator generates two voltage pulse signals having frequency equal to resonance frequency of transformer but being reverse to each other in phase, which signals are applied to primary electrodes, respectively to produce high voltage AC output across secondary electrodes isolated from primary electrodes.

Voltage converter for use with a piezoelectric transformer

On a first piezoelectric sheet of a piezoelectric vibrator, a second piezoelectric sheet is stacked with interposition, between the sheets, of first-set electrodes, formed on an upper surface of the first piezoelectric sheet. Second-set electrodes are formed on an upper surface of the second piezoelectric sheet with each placed halfway between two adjacent ones of the first-set electrodes. The second piezoelectric sheet is poled in directions from each second-set electrode to the two adjacent ones of the first-set electrodes. Preferably, third-set electrodes are formed on a lower surface of the first piezoelectric sheet with each arranged halfway between two adjacent ones of the first-set electrodes. In this event, the first piezoelectric sheet is poled in directions from each third-set electrode to two adjacent ones of the first-set electrodes. Each first-set electrode has a first end along a side surface of the first piezoelectric sheet with each second-set and each third-set electrode possessed of a second and a third end along opposite side surfaces of the first and the second piezoelectric sheets. First and second common outside electrodes are formed on such side surfaces in contact with the first end of each first-set electrode either directly or through a first common electrode and in contact with the second and the third ends of the second-set and the third-set electrodes either directly or through second and third common electrodes.

Method of manufacturing a piezoelectric vibrator capable of reliably

On a first piezoelectric sheet of a piezoelectric vibrator, a second piezoelectric sheet is stacked with interposition, between the sheets, of first-set electrodes (24(1), 24(2)) formed on an upper surface of the first piezoelectric sheet. Second-set electrodes are formed on an upper surface of the second piezoelectric sheet with each placed halfway between two adjacent ones of the first-set electrodes. The second piezoelectric sheet is poled in directions from each second-set electrode to the two adjacent ones of the first-set electrodes. Preferably, third-set electrodes are formed on a lower surface of the first piezoelectric sheet with each arranged halfway between two adjacent ones of the first-set electrodes. In this event, the first piezoelectric sheet is poled in directions from each third-set electrode to two adjacent ones of the first-set electrodes. Each first-set electrode has a first end along a side surface of the first piezoelectric sheet with each second-set and each third-set electrode possessed of a second and a third end along opposite side surfaces of the first and the second piezoelectric sheets. First and second common outside electrodes are formed on such side surfaces in contact with the first end of each first-set electrode either directly or through a first common electrode and in contact with the second and the third ends of the second-set and the third-set electrodes either directly or through second and third common electrodes.

Growing community of inventors

Miyagi, Japan

Yoshiaki Fuda