Hosei University

Yokogawa Electric Corporation

Nexty Electronics Corporation

Mitsuru Shinagawa

Yoshinori Matsumoto

Jun Katsuyama

Kazuhiro Watanabe

Hiroaki Tanaka

Kohei Hamamura

Naohiro Shimizu

A measurement device includes an electric field generator, an electric field detector, a thickness gauge, and a processor. The electric field generator generates an alternating current electric field. The electric field detector detects the alternating current electric field generated by the electric field generator. The thickness gauge measures a thickness of a measurement target in a non-contact manner. The processor derives a calibration curve representing a relationship between a specific dielectric constant and an intensity of an alternating current electric field. The measurement target is insertable between the electric field generator and the electric field detector. The electric field detector detects an intensity of the alternating current electric field attenuated by the measurement target. The processor calculates a specific dielectric constant of the measurement target based on the detected intensity of the alternating current electric field, the measured thickness, and the derived calibration curve.

Measurement device and measurement method

An electric field sensor includes a light source; an electro-optical crystal, a first separator, a first wavelength plate, first and second light receivers, a differential amplifier, and a controller. The electro-optical crystal has light from the light source incident thereon and receives an electric field generated by an object. The first separator separates light emitted from the electro-optical crystal into a P wave and an S wave. The first wavelength plate changes a phase of light at a pre-stage of the first separator. The first and second light receivers receive the P wave and S-wave light respectively, and convert the received light into first and second electrical signals, respectively. The differential amplifier generates a differential signal between the first and second electrical signals. The controller adjusts a wavelength of the light source such that an output value of a direct-current component of the differential amplifier is within a value range.

Electric field sensor

An electric field sensor which measures an electric field generated by a target utilizing an electro-optic effect, the electric field sensor including a light source, an electro-optic crystal on which light in a predetermined polarization state emitted from the light source is incident and which is subjected to the electric field generated by the target, a reference electric field applicator configured to apply an electric field based on a reference signal with a known signal level to the electro-optic crystal, a light receiver configured to receive light emitted from the electro-optic crystal and to convert the received light into an electric signal, and a separation corrector configured to separate the electric signal into a measurement signal based on the electric field generated by the target and the reference signal and to correct a signal level of the measurement signal on the basis of the signal level of the separated reference signal.

Electric field communication that adopts a metal as a communication medium is performed. An electric field communication system communicating through an electric field, includes: a communication medium made of a material capable of transmitting the electric field; a first transmitter that generates an electric field dependent on a potential difference between a first electrode, which is disposed on a side of the communication medium and is connected to the communication medium via a coupling capacitance, and a second electrode connected to an earth ground via a coupling capacitance, with the first electrode being connected on a signal side of the transmitter, and the second electrode being connected on a ground side of the transmitter; and a first receiver disposed in contact with the communication medium, wherein the first transmitter and the first receiver communicate with each other through the electric field via the communication medium.

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Tokyo, Japan

Mitsuru Shinagawa