Tokin Corporation

Nec Tokin Corporation

Hiroshi Shimizu

Tetsuo Yoshida

Yoshiaki Fuda

Naoki Wako

Hiroshi Abe

Naoki Wakou

Tomeji Ohno

Toru Ueno

Hiroshi Watanabe

Katsunori Kumasaka

Yoshihiro Ino

Kazuya Mori

Hutoshi Shiotani

Chikara Mashiko

A dielectric layer variable in dielectric constant in dependence upon the strain is formed on at least a part of an outer peripheral surface of a bar having a circular cross section. Interdigital electrodes are faced to the dielectric layer to thereby form a single capacitor. The interdigital electrodes have a plurality of linear electrodes and inclined at a predetermined inclination angle with respect to a center axis of the bar. Preferably, the dielectric layer is provided with a cylindrical insulator faced thereto with a small gap kept therebetween, and the linear electrodes are formed on the peripheral surface of the cylindrical insulator. The linear electrodes may be formed directly on the surface of the dielectric layer.

Capacitive torque sensor and method of detecting torque

A capacitive strain sensor comprises a substrate ( ) and a pair of interdigital electrode capacitors ( A) formed on the substrate. A dielectric thick film ( ) having a uniform thickness and made of a material the dielectric constant of which varies with strain is provided on an elastic body having a flat or curved surface on the substrate ( ). A block ( ) for preventing strain from being produced is secured to one end of the substrate ( ); a weight ( ) is secured to the other end. The capacitors ( A) are formed by interdigitally arranging a pair of electrodes being parallel linear electrodes of linear conductors on the substrate.

Capacitive strain sensor and method for using the same

A piezoelectric vibratory gyroscope utilizing an energy-trapping vibration mode comprises a piezo-electric plate having a principal surface and polarized in a thickness direction, and first through n-th electrodes (n being an integer not smaller than three) formed in a generally central area of the principal surface at positions corresponding to first through n-th vertexes of a polygon having n angles. When the piezoelectric plate is excited in the energy-trapping vibration mode of a primary vibration, rotation of the piezoelectric plate around an axis perpendicular to the principal surface of said piezoelectric plate produces the Coriolis force to excite a secondary vibration which induces electric voltages at the first through the n-th electrodes. A voltage difference is detected for at least two of the first through the n-th electrodes.

Piezoelectric vibratory gyroscope utilizing an energy-trapping vibration

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

In a piezoelectric gyroscope system wherein a vibrating body is vibrated in a specific direction by a piezoelectric actuator and is subjected to another vibration in a direction perpendicular to the specific direction due to the Coriolis' force upon being subjected to a rotation of a rotational speed, the perpendicular vibration being detected as an electric signal representative of the rotational speed by a piezoelectric transducer, the vibrating body is made of a circular rod of a piezoelectric material having a plurality of elongated electrodes on the outer surface of the rod, in order to resolve difficulty for mounting piezoelectric transducers onto the vibrating body. A driving signal is applied to predetermined ones of the electrodes to vibrate the rod in a particular diametric direction and an output signal is detected from specific ones of the electrodes according to the vibration due to the Coriolis' force. When an even number of electrodes are provided, those electrodes are formed at equiangularly spaced positions on the outer surface of the rod. When an odd number of electrodes are provided, those electrodes are formed at equiangularly spaced positions within an angular region of (360 angular degrees.times.2/3) on the outer surface of the rod.

Gyroscope using circular rod type piezoelectric vibrator

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.

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Sendai, Japan

Tetsuo Yoshida