Abstract: In the present invention, a pump driving circuit includes a step-up unit that steps up a first DC voltage from a power supply and outputs it as a second DC voltage, and an H bridge unit that has first and second series circuits that each include two switching elements connected in series between a high potential corresponding to the second DC voltage and a reference potential. According to a control signal from the control unit, the two switching elements of the first series circuit and the two switching elements of the second series circuit are switched on and off. A voltage generated between a first contact point between the two switching elements of the first series circuit, and a second contact point between the two switching elements of the second series circuit is used as a driving voltage for driving a pump.

Abstract: A gas control apparatus includes an upper housing to which a second piezoelectric pump is joined, a lower housing to which a first piezoelectric pump is joined, and a diaphragm. The upper housing includes a discharge hole through which gas is discharged. The lower housing includes introduction holes through which gas is introduced, an opening, a first valve seat, a second valve seat, and a third valve seat. The diaphragm is sandwiched between the upper housing and the lower housing, and is fixed to the upper housing and the lower housing so that the diaphragm contacts the first valve seat, the second valve seat, and the third valve seat. The diaphragm divides an inner space of the upper housing and the lower housing to define valve chests together with the upper housing and the lower housing.

Abstract: A piezoelectric microblower includes a vibrating plate including a piezoelectric element and arranged to be driven in a bending mode by applying a voltage of a predetermined frequency to the piezoelectric element, and a blower body arranged to fix both ends or a periphery of the vibrating plate and to define a blower chamber between the blower body and the vibrating plate, an opening being provided in a portion of the blower body facing a central portion of the vibrating plate. In a portion of the blower chamber corresponding to the central portion of the vibrating plate, a partition is provided around the opening and a resonance space is defined inside of the partition. A size of the resonance space is set such that a driving frequency of the vibrating plate and a Helmholtz resonance frequency of the resonance space correspond to each other.

Abstract: A piezoelectric micro-blower capable of efficiently conveying compressive fluid without use of a check valve and ensuring a sufficient flow rate. The micro-blower has a blower body with a first wall and a second wall. Openings are formed in the respective walls and face a center of a diaphragm. An inflow path allowing the openings to communicate with the outside is formed between the walls. By applying a voltage to a piezoelectric element to cause the diaphragm to vibrate, a part of the first wall close to the first opening vibrates. Thus, gas can be drawn from the inflow path and discharged from the opening in the second wall.

Abstract: A fluid supply device includes a fluid supply source, a valve, a differential-pressure generator, and a pressurizing device. The valve includes a casing, a displacement member that divides an inside of the casing into a first valve chamber and a second valve chamber, the displacement member being displaced by a pressure of a fluid being exerted on a front main surface and a back main surface of the displacement member, a first opening provided in the first valve chamber, a second opening provided in the first valve chamber, and a third opening provided in the second valve chamber. Thus, flow rate fluctuations are reduced even when the pressure on the ejection side or the suction side of the device fluctuates due to changes in atmospheric conditions.

Abstract: In a piezoelectric actuator driver circuit, a resistor provided to detect current is inserted in a current path for a piezoelectric actuator. A signal of a decreased voltage of the resistor is subjected to positive feedback to an amplifier circuit via a band-pass filter. An output signal of the amplifier circuit is subjected to negative feedback to the amplifier circuit via a band-elimination filter. The band-pass filter allows a signal of a fundamental resonant frequency of a piezoelectric device, which includes the piezoelectric actuator, to pass therethrough, and the band-elimination filter blocks the signal of the fundamental resonant frequency. Thus, a loop gain at a higher-order resonant frequency with respect to the fundamental resonant frequency becomes very low and a higher-order resonant mode can be effectively suppressed.

Abstract: A piezoelectric micropump in which a pump chamber is isolated by a diaphragm. A piezoelectric element is disposed on a back surface of the diaphragm, and the diaphragm is deformed by bending deformation of the piezoelectric element to change the volume of the pump chamber and transport fluid in the pump chamber. A support member for supporting a back surface of the piezoelectric element is provided so that the support member inhibits bending of a peripheral portion of the diaphragm in a reverse direction. The support member thus prevents the piezoelectric element from being floated. Accordingly, the displacement of the piezoelectric element can be reliably transmitted as the change in volume of the pump chamber, thereby enhancing the fluid transportation performance.

Abstract: An electronic-component high-frequency characteristic error correcting method for allowing a calibration work to be performed on a two-terminal impedance component using the same correction-target measuring system as that used in actual measurement. At least three correction data acquisition samples having different high-frequency characteristics are measured by a reference measuring system and an actual measuring system. An equation for associating the value measured by the actual measuring system with the value measured by the reference measuring system using an error correction coefficient of a transmission line is determined. A given electronic component is measured by the actual measuring system. An estimated high-frequency characteristic value of the electronic component obtained when the electronic component is measured by the reference measuring system is calculated using the determined equation.

Abstract: In a piezoelectric actuator driver circuit, a resistor provided to detect current is inserted in a current path for a piezoelectric actuator. A signal of a decreased voltage of the resistor is subjected to positive feedback to an amplifier circuit via a band-pass filter. An output signal of the amplifier circuit is subjected to negative feedback to the amplifier circuit via a band-elimination filter. The band-pass filter allows a signal of a fundamental resonant frequency of a piezoelectric device, which includes the piezoelectric actuator, to pass therethrough, and the band-elimination filter blocks the signal of the fundamental resonant frequency. Thus, a loop gain at a higher-order resonant frequency with respect to the fundamental resonant frequency becomes very low and a higher-order resonant mode can be effectively suppressed.

Abstract: In a piezoelectric-actuator driving circuit for driving a piezoelectric actuator, an amplifier circuit amplifies a signal output from a feedback circuit and supplies the amplified signal to a non-inverting amplifier circuit and an inverting amplifier circuit. The non-inverting amplifier circuit amplifies the output voltage of the amplifier circuit with a predetermined gain and applies the amplified voltage to a first terminal of the piezoelectric actuator. The inverting amplifier circuit inverts and amplifies the output voltage of the amplifier circuit with the same gain as that of the non-inverting amplifier circuit and then applies the amplified voltage to a second terminal of the piezoelectric actuator through resistors. The feedback circuit amplifies a difference between voltages at respective ends of the resistor and supplies the amplified difference to the amplifier circuit.

Abstract: A fluid conveyance device includes a substrate, and a disk-shaped piezoelectric element arranged in a bendable manner on the substrate. A plurality of substantially circular concentric segment electrodes are provided on the piezoelectric element, and are provided with voltages with phases that are shifted. A wavy ring deformation is thus produced on the piezoelectric element. A pocket produced between the piezoelectric element and the substrate is moved in a radial direction so as to convey a fluid from an outer substantially circular portion to a central portion and to discharge the fluid from the central portion.

Abstract: A fluid conveyance device includes a substrate, and a disk-shaped piezoelectric element arranged in a bendable manner on the substrate. A plurality of substantially circular concentric segment electrodes are provided on the piezoelectric element, and are provided with voltages with phases that are shifted. A wavy ring deformation is thus produced on the piezoelectric element. A pocket produced between the piezoelectric element and the substrate is moved in a radial direction so as to convey a fluid from an outer substantially circular portion to a central portion and to discharge the fluid from the central portion.

Abstract: In a piezoelectric actuator driver circuit, a resistor provided to detect current is inserted in a current path for a piezoelectric actuator. A signal of a decreased voltage of the resistor is subjected to positive feedback to an amplifier circuit via a band-pass filter. An output signal of the amplifier circuit is subjected to negative feedback to the amplifier circuit via a band-elimination filter. The band-pass filter allows a signal of a fundamental resonant frequency of a piezoelectric device, which includes the piezoelectric actuator, to pass therethrough, and the band-elimination filter blocks the signal of the fundamental resonant frequency. Thus, a loop gain at a higher-order resonant frequency with respect to the fundamental resonant frequency becomes very low and a higher-order resonant mode can be effectively suppressed.

Abstract: A valve includes a valve body, a diaphragm dividing the inside of the valve body into first and second valve chambers and being displaced under a pressure of fluid, first and second openings in communication with the first valve chamber, and a third opening in communication with the second valve chamber. When a pump is not driven, the force applied to a side of the diaphragm facing the second valve chamber is greater than the force applied to a side of the diaphragm facing the first valve chamber, and the second opening is sealed by the diaphragm. When the pump is driven and the force applied to the side of the diaphragm facing the first valve chamber becomes greater than the force applied to the side of the diaphragm facing the second valve chamber, the diaphragm allows the first and second openings and to communicate with each other.

Abstract: A piezoelectric fan includes a blade that is joined to a piezoelectric oscillator that bends in response to an application of a voltage, and the blade of the piezoelectric fan is arranged to swing in a space between neighboring heat dissipating fins of a heat sink. The formation of a hole in the blade increases the amplitude of the blade and also improves the sweep effect of sweeping high-temperature air in the vicinity of the wall of the heat dissipating fin, and thus, improves the cooling capability of the piezoelectric fan.

Abstract: A piezoelectric pump includes a pump body with a pump chamber, and a piezoelectric element that closes the pump chamber. The central area and the peripheral area of the piezoelectric element are bent in opposite directions by applying voltages to the piezoelectric element so that the volume of the pump chamber is changed. The piezoelectric element is a laminate including a plurality of piezoelectric layers with electrodes interposed therebetween. The central area and the peripheral area of each piezoelectric layer are polarized opposite to each other in the thickness direction, and the electrodes are formed such that voltages in the same direction in the thickness direction are applied to the central area and the peripheral area of each piezoelectric layer. Since voltages at the same potential are applied to the electrodes formed in the same planes of the piezoelectric layers, short-circuits caused by migration can be prevented.

Abstract: A micropump having a diaphragm portion, a valve portion of an intake-side check valve, and a valve portion of a discharge-side check valve formed in a single elastic-member sheet. A piezoelectric actuator is attached onto a back surface of the diaphragm portion. The elastic-member sheet is sandwiched between a first case member and a second case member, the elastic-member sheet providing sealing between both case members. A vibration chamber is defined between the elastic-member sheet and the first case member, the vibration chamber housing the piezoelectric actuator. A pump chamber is defined between the elastic-member sheet and the second case member.

Abstract: A fluid conveyance device includes a substrate, and a disk-shaped piezoelectric element arranged in a bendable manner on the substrate. A plurality of substantially circular concentric segment electrodes are provided on the piezoelectric element, and are provided with voltages with phases that are shifted. A wavy ring deformation is thus produced on the piezoelectric element. A pocket produced between the piezoelectric element and the substrate is moved in a radial direction so as to convey a fluid from an outer substantially circular portion to a central portion and to discharge the fluid from the central portion.

Abstract: A blower body is provided with a first wall and a second wall, and openings are provided in the walls at positions facing the approximate center of a diaphragm. An inflow passage that allows the openings to communicate with the outside is arranged between the two walls. When the diaphragm is vibrated in response to a voltage applied to a piezoelectric element, the first wall vibrates near the opening and sucks in air from the inflow passage so that the air can be ejected from the opening. A plurality of branch passages which provide sound absorption are connected to an intermediate section of the inflow passage so as to prevent noise generated near the opening from leaking from an inlet.

Abstract: In a piezoelectric actuator driver circuit, a resistor provided to detect current is inserted in a current path for a piezoelectric actuator. A signal of a decreased voltage of the resistor is subjected to positive feedback to an amplifier circuit via a band-pass filter. An output signal of the amplifier circuit is subjected to negative feedback to the amplifier circuit via a band-elimination filter. The band-pass filter allows a signal of a fundamental resonant frequency of a piezoelectric device, which includes the piezoelectric actuator, to pass therethrough, and the band-elimination filter blocks the signal of the fundamental resonant frequency. Thus, a loop gain at a higher-order resonant frequency with respect to the fundamental resonant frequency becomes very low and a higher-order resonant mode can be effectively suppressed.