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Tdk Corporation

Tdk Electronics Company, Limited

Kohji Toda

Yasuo Niwa

Kohji Takahashi

Koji Takahashi

Isao Matsufuji

An apparatus for generating electric energy comprises a vibration plate, a supporting board, at least one side-wall unit and at least one piezoelectric substrate having a first- and a second end surfaces covered with a first- and a second electrodes, respectively. They all together form at least one cavity resonator. If a sound pressure from the outside arrives at the vibration plate, an acoustic vibration is excited in the vibration plate, and thereby a resonance vibration is induced in the cavity resonator. In this time, the piezoelectric substrate responds collectively to the resonance vibration. Thus, a resonance energy occurred in the cavity resonator is converted into an electric energy, which is delivered through the first- and second electrodes.

Apparatus for generating electric energy

When input electric signals E(i=1, 2, . . . , n) with frequencies f(i=1, 2, . . . , n), respectively, are applied to an input interdigital transducer, elastic waves are excited in a piezoelectric substrate. Leaky components of the elastic waves are radiated into a material in the form of longitudinal waves, which are reflected at a bottom boundary-surface of the material. One of reflected longitudinal waves are detected at an output interdigital transducer as a delayed output signal with one of the frequencies f. When the delayed output signal is applied to at least one interdigital transducer for radiation, an elastic wave is excited in the piezoelectric substrate. A leaky component of the elastic wave is radiated into the material in the form of a longitudinal wave, which is reflected at the bottom boundary-surface and re-reflected at a top boundary-surface of the material, and thus a continuous reflection occurs.

Ultrasound radiation device into a material

An ultrasound radiation device comprises a piezoelectric substrate, an interdigital arrangement of two comb-shaped electrodes formed on an upper end surface of the piezoelectric substrate, a counter electrode formed on a lower end surface of the piezoelectric substrate, an interdigital transducer formed on said upper end surface of said piezoelectric substrate, and an amplifier between one of the two comb-shaped electrodes and the interdigital transducer. If an electric signal is applied between the counter electrode and one of the two comb-shaped electrodes, a longitudinal wave composed of the main lobe and grating lobes is radiated into a material in contact with the counter electrode, as well as a Lamb wave is excited in the piezoelectric substrate. The Lamb wave is detected as a delayed electric signal at the interdigital transducer. The delayed electric signal is amplified by the amplifier, and used as an input electric signal again.

Ultrasound radiation device

A reflective liquid-crystal display comprises a display assembly and a piezoelectric assembly, on which the display assembly is formed. The display assembly is composed of first- and second transparent nonpiezoelectric-plates having first- and second transparent electrodes, respectively, and a liquid crystal between thereof. The piezoelectric assembly is composed of a piezoelectric substrate, at least one electrode under the piezoelectric substrate, and a counter electrode over the piezoelectric substrate. If a first electric signal is applied to the piezoelectric assembly, a transition from a transparent- to an opaque state in the liquid crystal occurs. In this time, if a second electric signal is applied to a part of the liquid crystal, a transition from the opaque- to the transparent state in the liquid crystal occurs. Thus, a light through the part of the liquid crystal is reflected at the counter electrode.

Reflective liquid-crystal display

An ultrasonic security system for personal computer comprises a touch-panel section, a lock section, and a key section. The touch-panel section comprises a nonpiezoelectric plate, at least one transducer-unit, and a signal analyzer. The transducer-unit consists of at least one input IDT T (i&equals;1, 2, . . . , m), at least one output IDT R (i&equals;1, 2, . . . , m), a first input piezoelectric substrate, and a first output piezoelectric substrate. The lock section comprises a second piezoelectric substrate, a coding IDT consisting of interdigital electrode pairs and having a coded pattern, and a terminal IDT having the electrode-finger direction parallel to that of the coding IDT. The key section comprises a third piezoelectric substrate, an initial IDT, and a decoding IDT having the same construction pattern as the coding IDT. If touching a position on the nonpiezoelectric plate, an electric signal appears at the output IDT R . The electric signal is applied to the coding IDT, and is detected as a coded burst-signal at the terminal IDT. The coded burst-signal arrives at the initial IDT. And then, a pulse is detected at the decoding IDT, if the coded burst-signal correlates to the coded pattern. As a result, the touch position is sensed by means of the phase of the pulse at the signal analyzer. In other words, no key section or a key section with a decoding IDT having the different construction pattern from the coding IDT causes no pulse. Consequently, far from sensing the touch position, it is not possible to operate the PC preparing such the ultrasonic security system for personal computer.

Ultrasonic security system for personal computer

A bridge-type ultrasonic atomizer comprises input- and output piezoelectric substrates, first- and second electrodes formed on the input piezoelectric substrate, third- and fourth electrodes formed on the output piezoelectric substrate, a porous nonmetalic-plate formed between the input- and output piezoelectric substrates. When an input electric signal is applied between the first- and second electrodes, a first acoustic vibration is excited in the input piezoelectric substrate. The first acoustic vibration makes a liquid in the porous nonmetalic-plate to be atomized, at the same time, causes a second acoustic vibration in the output piezoelectric substrate only when the liquid exists in the porous nonmetalic-plate. The second acoustic vibration is detected as a delayed electric signal between the third- and fourth electrodes, and is fed back to the first- and second electrodes again. As a result, the porous nonmetalic-plate prevents the operation without liquid.

Bridge-type ultrasonic atomizer

A device for measuring sound velocity in material comprises a piezoelectric substrate, first- and second comb-shaped electrodes, a counter electrode, and a reflector. When input electric signals with a frequency f, respectively, are applied between the first comb-shaped electrode and the counter electrode in turn, longitudinal waves are radiated into a material existing between the counter electrode and the reflector, and then, reflected at the reflector, and after all, detected between the second comb-shaped electrode and the counter electrode as delayed electric signals D in accordance with distances Z between the counter electrode and the reflector. Electrical coupled-signals from the input electric signals and the delayed electric signals D interfere respectively, so that respective interference signals R occur. A sound velocity V in the material is estimated from the frequency f and the interference signals R .

Device for measuring sound velocity in material

An ultrasonic coding modem for digital network communication comprises a transmitting device having a first piezoelectric substrate, and a receiving device having a second piezoelectric substrate. If a message digital-signal is applied to the transmitting device, a SAW is excited on the first piezoelectric substrate and is delivered as a coded digital signal into a digital network. On the other hand, if the coded digital-signal is received at the receiving device from the digital network, a SAW is excited on the second piezoelectric substrate. In this time, if the SAW excited on the second piezoelectric substrate is corresponding to the SAW excited on the first piezoelectric substrate, an output digital-signal, which is equivalent to the message digital-signal, is delivered from the receiving device. As a result, it is possible to keep a base-band communication secret.

Ultrasonic coding modem for digital network communication

A coding and decoding system for wireless telecommunication comprises a wireless telecommunication device and a personal card. The wireless telecommunication device consists of a first piezoelectric substrate, a coded IDT, a first electrode-group, a first amplifier, an antenna, a second amplifier, a second electrode-group, a first intermediary IDT, and a signal analyzer. The personal card attached to the wireless telecommunication device consists of a second piezoelectric substrate, a personal coded IDT, a third electrode-group, a second intermediary IDT. The coding and decoding system for wireless telecommunication has four sections, that is, (1) a personal transmitting section (2) a main transmitting section (3) a personal receiving section and (4) a main receiving section.

Coding and decoding system for wireless telecommunication

An ultrasonic moving-speed measuring system comprises a piezoelectric substrate, a thickness-vibration mode transducer, an interdigital transducer, and a signal analyzer. The piezoelectric substrate, the thickness-vibration mode transducer, and the interdigital transducer form a transducing assembly. When an input electric signal with a carrier frequency is applied to the thickness-vibration mode transducer, a longitudinal wave is radiated into a medium that is in touch with the bottom of the transducing assembly. If the longitudinal wave is reflected at a material in the medium, a delayed electric signal with a Doppler frequency is detected at the interdigital transducer via a mode conversion from a reflected longitudinal wave to a leaky Lamb wave. The moving speed of the material is sensed at the signal analyzer in terms of a difference between the carrier- and Doppler frequencies.

Ultrasonic moving-speed measuring system

An ultrasonic recognition system on digital communication comprises an identification card, a detail communication device attached to a detail computer, and a master communication device attached to a master computer. The identification card consists of a first piezoelectric substrate, an individual coded IDT, and a first intermediary IDT. The detail communication device consists of a second piezoelectric substrate and transmitting- and receiving sections. The transmitting section is composed of a bipolar-pulse generator, a first coded IDT, a second coded IDT, a second intermediary IDT, an electrode group, a synchronizing device, an envelope detecting device, and a monopolar-pulse generator. The receiving section is composed of a third intermediary IDT, a third coded IDT, a fourth coded IDT, and a detecting device. If the identification card is set in the detail communication device, a pulse is generated at the bipolar-pulse generator at regular intervals. When the pulse is applied to the individual coded IDT, an individual SAW is excited on the first piezoelectric substrate. The individual SAW is detected at the first intermediary IDT as an individual coded burst-signal, which is received at the electrode group and is converted into an individual coded digital-signal at the monopolar-pulse generator. The individual coded digital-signal is delivered into a digital network. When the individual coded digital-signal is received by the master communication device, the signal decoding is achieved, so that the identification-card singularity is recognized by the master communication device.

Ultrasonic recognition system on digital communication

A transmitting and receiving system for digital communication on electric power-lines comprises a transmitting device and a receiving device. The transmitting device consists of an input terminal, a bipolar-pulse generator, a first piezoelectric substrate, first- and second coded IDTs, a first intermediary IDT, an electrode group, a synchronizing device, an envelope detecting device, a monopolar-pulse generator, and a mixer connected with electric power-lines. The receiving device consists of a receiving connector connected with the electric power-lines, a tuning coil, a second piezoelectric substrate, a second intermediary IDT, third- and fourth coded IDTs, a detecting device, and a detecting terminal. If a message digital-signal is applied to the bipolar-pulse generator via the input terminal, high-frequency bipolar-pulses (&minus;1 and 1) are generated, and after all, are transduced to first- and second coded digital-signals at the monopolar-pulse generator. The first- and second coded digital-signals are delivered into the electric power-lines via the mixer. On the other hand, if the first coded digital-signal is received at the receiving connector, the first coded digital-signal is applied to the second intermediary IDT via the tuning coil. The first coded digital-signal is, after all, transduced to a first decoded pulse at the third coded IDT. In the same way, the second coded digital-signal is transduced to a second decoded pulse at the fourth coded IDT. As a result, an output digital-signal, which is composed of the first- and second decoded pulses and is equivalent to the message digital-signal, is detected at the detecting terminal via the detecting device.

Transmitting and receiving system for digital communication on electric power-lines

A system for measuring sound velocity in material comprises a piezoelectric substrate, first- and second comb-shaped electrodes, and a counter electrode in contact with a surface-part of a material. When input electric signals E having carrier frequencies f , respectively, are applied between the first comb-shaped electrode and the counter electrode in turn, longitudinal waves are radiated into the material. The longitudinal waves are reflected at the opposite surface-part of the material, and then, detected between the second comb-shaped electrode and the counter electrode as delayed electric signals D , respectively. The input electric signals E and the delayed electric signals D interfere respectively, so that respective interference signals R occur. A sound velocity V in the material is estimated from the interference signals R .

System and measuring sound velocity in material

An ultrasound radiating and receiving device comprises a piezoelectric substrate, an interdigital arrangement of first and second comb-shaped electrodes, and a counter electrode. The interdigital arrangement is mounted on an upper end surface of the piezoelectric substrate. The counter electrode is formed on a lower end surface of the piezoelectric substrate, and is in contact with a surface-part of a material through the lower end surface of the counter electrode. When an input electric signal is applied between the first comb-shaped electrode and the counter electrode, a longitudinal wave is radiated into the material through the surface-part of the material along the direction vertical to the lower end surface of the piezoelectric substrate. If the longitudinal wave is reflected at an object located inside the material, a reflected longitudinal wave is detected between the second comb-shaped electrode and the counter electrode as a delayed electric signal.

Ultrasound radiating and receiving device

A vibration displacement sensing system comprises a piezoelectric substrate, first- and second comb-shaped electrodes, a counter electrode, and a signal analyzer. When input electric signals are applied between the first comb-shaped electrode and the counter electrode, longitudinal waves are radiated into a medium, and reflected at a material in the medium. If the material vibrates in response to times T , reflected longitudinal waves are detected between the second comb-shaped electrode and the counter electrode as delayed electric signals D in accordance with distances Z between the counter electrode and the material. In this time, the distances Z correspond with the times T , respectively. Electrical coupled-signals from the input electric signals and the delayed electric signals D interfere respectively, so that respective interference signals R occur. A vibration displacement caused by the material is estimated from the interference signals R .

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Yokosuka, Japan

Kohji Toda