Taiheiyo Cement Corporation

Other

Katsuyuki Ishikawa

Takeshi Fujimura

Masaaki Toyama

Takahiro Yamakawa

Masako Kataoka

Toshiyuki Terada

Yoshikazu Inoue

Toru Ezaki

Tatsuya Goto

Keizo Tsukamoto

Katsumi Uesawa

There are provided a piezoelectric device, in which piezoelectric element surfaces are prevented from cracking and warping by reducing tensile stress generated within the piezoelectric element by an external force, and a piezoelectric switch utilizing the same. The piezoelectric device comprises a piezoelectric element having a plate-like shape including a piezoelectric body having a plate-like shape and polarized in a thickness direction thereof and a pair of electrodes formed on both main surfaces of the piezoelectric body, and a pair of elastic conductive members fixed to the both main surfaces of the piezoelectric element, wherein when an external force is applied, the piezoelectric body is deformed to generate electricity.

Piezoelectric device and piezoelectric switch provided with the same

Of a plurality of surfaces forming its shape, a piezoelectric transformerA has two types of output electrodesandon one surface in the longitudinal direction and two opposing surfaces in the lateral direction. This piezoelectric transformerA can be driven by properly switching first and second resonance modes different from each other. In a strobe apparatus, a discharge capacitoris charged by a voltage generated in the output voltagewhen the piezoelectric transformerA is driven in the first resonance mode, and a discharge tubeis triggered by a voltage generated in the output electrodewhen the piezoelectric transformerA is driven in the second resonance mode.

Piezoelectric transformer and strobe apparatus having the piezoelectric transformer

A strobe apparatus has a discharge capacitor charged by a voltage generated in the output voltage when a piezoelectric transformer is driven in the first resonance mode, and a discharge tube is triggered by a voltage generated in the output electrode when the piezoelectric transformer is driven in the second resonance mode. The transformer has two types of output electrodes and on one surface in the longitudinal direction and two opposing surfaces in the lateral direction. It can be driven by properly switching first and second resonance modes different from each other.

In an electronic flash device, a driving circuit ( ) drives a piezoelectric transformer ( ) in response to an oscillation signal of a predetermined frequency, which is output from an oscillation circuit ( ). A switch ( ) is provided in series in a line that connects the output of the piezoelectric transformer ( ) and a capacitor ( ). When the switch ( ) is ON, the output voltage from the piezoelectric transformer ( ) is rectified by a rectifier circuit, and charges the discharge capacitor ( ) as electric energy for discharging a discharge tube ( ). When the switch ( ) is turned off, and the output voltage from the piezoelectric transformer ( ) is applied to the discharge tube ( ), the discharge tube ( ) emits flash light by the electric energy stored in the discharge capacitor ( ) in response to that applied voltage as a trigger.

Electronic flash device

In a piezoelectric transformer control circuit, when a load ( ) is disconnected from a piezoelectric transformer ( ) and changes to an open state, an output detection voltage (Vdet) becomes higher than a reference voltage (Vref ), and the output from a voltage comparator ( ) goes &ldquo;Low&rdquo;. When the output of the piezoelectric transformer ( ) is short-circuited to GND, the output detection voltage (Vdet) abruptly drops to almost &ldquo;0&rdquo; and becomes lower than a reference voltage (Vref ). The output from a voltage comparator ( ) goes &ldquo;Low&rdquo;. A voltage-controlled oscillation circuit ( ) detects the signal &ldquo;Low&rdquo; to stop the generation of the oscillation signal to a driving circuit ( ) for driving the piezoelectric transformer ( ).

Control circuit and method for protecting a piezoelectric transformer from an open state and a short-circuited state

Mount terminals ( ) formed on the end faces of a housing ( ) in the longitudinal direction respectively abut against external electrodes ( ) which are formed on an end face of a piezoelectric element ( ) in the longitudinal direction and used to apply input voltage, and an external electrode ( ) for extracting output voltage. These abutted portions are fixed by soldering or with conductive adhesive to electrically connect the mount terminals to the external electrodes and fix the piezoelectric element ( ) inside the housing ( ).

Piezoelectric transformer element and method of mounting it in a housing

Mount terminals (,) are formed on end faces of a housing (,). These mount terminals serve to mount the housing (,) on a circuit board and also serves as lead electrodes for the outer and output electrodes of a piezoelectric device to be housed in the case. The piezoelectric device is fixed in the housing (,) by using the lead electrodes (,) integrally formed with mount terminals (,) and projections (,).

Housing for piezoelectric transformer device

In a piezoelectric transformer control circuit for driving a load (,) connected to a piezoelectric transformer (,), an oscillation signal as a basis of driving of the piezoelectric transformer (,) is oscillated, and the piezoelectric transformer (,) is driven by a driving circuit (,) on the basis of the oscillation signal. A pulse power supply circuit (,) for supplying a pulse voltage to the driving circuit (,) intermittently drives the driving circuit (,) by pulse-modulating the pulse voltage to be supplied to the driving circuit (,).

System for driving a cold-cathode fluorescent lamp connected to a piezoelectric transformer

When an input voltage rises, (the amplitude of) a sine-wave voltage for driving a piezoelectric transformer (,) increases, so that a detection voltage (Vti) rectified by a rectifying circuit (,) also increases. An output voltage from an error amplifier (,) for comparing the detection voltage (Vti) with a reference voltage (Vref,) rises. If the output voltage from the error amplifier (,) rises, a voltage-controlled oscillation circuit (,) decreases the duty ratio of an oscillation signal to be output. In a driving circuit (,), as the duty ratio of the oscillation signal decreases, the amplitude of a fundamental wave contained in a rectangular wave to be output decreases to be a small driving voltage to the piezoelectric transformer (,).

Control circuit and method for piezoelectric transformer

In a piezoelectric transformer device (,), a plurality of inner electrodes are stacked on each other on the left side. These inner electrodes are alternately connected to each other through interlevel connection conductors to constitute two inner electrode groups. A secondary output electrode in the form of a mesh is formed near the end portion of the device (,) on the right side. Only primary input electrodes (,) connected to the two inner electrode groups, a secondary output electrode (,), and the lead electrode of the secondary output electrode in the form of a mesh are exposed on the same surface of the device.

Growing community of inventors

Tokyo, Japan

Katsuyuki Ishikawa