Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: In an optical modulator capable of modulating incident laser beam L by a compound semiconductor single crystal having a property of generating an electro-optic effect, the attenuation of the signal strength in a low frequency band is prevented without lowering the carrier concentration of the compound semiconductor. The optical modulator 23 comprises: incidence limiting means 25 which is provided on or near an incidence plane 24a, on which the laser beam L can be incident, of the compound semiconductor single crystal 24 so as to limit incidence of light other than the laser beam L on the incidence plane 24a; and a shielding member 26 which is formed from a low-permittivity material having a light blocking effect, and covers a surface 24c of the compound semiconductor single crystal 24 extending along a traveling direction of the laser beam L that entered the compound semiconductor single crystal 24.

Abstract: In an optical modulator capable of modulating incident laser beam L by a compound semiconductor single crystal having a property of generating an electro-optic effect, the attenuation of the signal strength in a low frequency band is prevented without lowering the carrier concentration of the compound semiconductor. The optical modulator 23 comprises: incidence limiting means 25 which is provided on or near an incidence plane 24a, on which the laser beam L can be incident, of the compound semiconductor single crystal 24 so as to limit incidence of light other than the laser beam L on the incidence plane 24a; and a shielding member 26 which is formed from a low-permittivity material having a light blocking effect, and covers a surface 24c of the compound semiconductor single crystal 24 extending along a traveling direction of the laser beam L that entered the compound semiconductor single crystal 24.

Abstract: A signal electrode (11A) and a ground electrode (11B) are disposed respectively on surfaces of a case (10). In this way, the signal electrode (11A) and the ground electrode (11B) do not come into contact with any electric component, such as a transmission circuit (21), disposed inside the case (10), and thus a reduction in an electric field (Ec) induced in an electric-field transmission medium can be prevented. In addition, a certain distance between the signal electrode (11A) and the ground electrode (11B) is kept, and thus a reduction in the electric field (Ec) induced in the electric-field transmission medium can be prevented. Furthermore, the contactability between the signal electrode (11A) and the electric-field transmission medium is improved, and thus the electric field (Ec) induced in the electric-field transmission medium can be increased.

Abstract: When a human hand (100) holds a transceiver (3a), the hand holds a bottom of an external wall surface and a side of the external wall surface of an insulating case (33). Therefore, a transmitting and receiving electrode (105) and an insulating film (107) cover not only the bottom of the external wall surface but also the side of the external wall surface of the insulating case (33). A first ground electrode (131), a second ground electrode (161), and a third ground electrode (163) are attached to upper portions of the internal wall surface of the insulating case (33) apart from the transmitting and receiving electrode (105). An insulating foam member (7a) is interposed between the insulating case (33) and a transceiver main body (30), and an insulating foam member (7b) is interposed between the transceiver main body (30) and a battery (6).

Abstract: The present invention relates to an electric field sensor including: a light source (1); an electro optic crystal (7) which is applied with an electric field based on a signal under test, in which a birefringent index changes according to the electric field, and which changes a polarization state of light incident from the light source according to the birefringent index and emits the light; and a detector (9, 17, 19, 21) that detects an electric signal according to the change of the polarization state of the light emitted from the electro optic crystal (7). Further, the electric field sensor includes: a signal electrode (11) for applying the electric field based on the signal under test to the electro optic crystal (7); a counter electrode (12) that forms a pair with the signal electrode (11); and an auxiliary electrode (61) that is electrically connected to the counter electrode (12), and that forms a capacitance with ground.

Abstract: A transmitter (2) modulates information to be transmitted with an alternating-current signal having a predetermined frequency and includes a variable reactance section (16) which produces resonance with a stray capacitance (18) between a circuit ground (17) in the transmitter (2) and an earth ground (20) which strays from the earth ground (20) and a stray capacitance (19) between the human body (3) and the earth ground (20).

Abstract: A signal electrode (11A) and a ground electrode (11B) are disposed respectively on surfaces of a case (10). In this way, the signal electrode (11A) and the ground electrode (11B) do not come into contact with any electric component, such as a transmission circuit (21), disposed inside the case (10), and thus a reduction in an electric field (Ec) induced in an electric-field transmission medium can be prevented. In addition, a certain distance between the signal electrode (11A) and the ground electrode (11B) is kept, and thus a reduction in the electric field (Ec) induced in the electric-field transmission medium can be prevented. Furthermore, the contactability between the signal electrode (11A) and the electric-field transmission medium is improved, and thus the electric field (Ec) induced in the electric-field transmission medium can be increased.

Abstract: A reactance adjuster includes an electrode (123) inducing an electric-field in an electric-field transmittable medium (121), an adjusting signal generation section (13) outputting alternatingly a high level or a low level signal to a resonance section (7), an electric-field detection section (15) generating an electric signal based on the electric-field in the medium (121), a first electric-charge storing means (C1) storing electric-charge according to the electric signal when the section (13) outputs a high level signal, a second electric-charge storing means (C2) storing electric-charge according to the electric signal when the section (13) outputs a low level signal, a voltage comparator (10) outputting a predetermined signal based on a voltage difference between the storing means, a control section (19) outputting a constant voltage when the first and the second storing means (C1, C2) are storing electric-charge and a voltage based on a predetermined signal when the storing ends.

Abstract: There is provided a transmission means (3) configured to transmit a modulated signal obtained by modulating data, a transmission electrode (8) that induces an electric field based on the modulated signal in an electric field transmission medium (20), a first reactance means (2) that is provided between the electric field transmission medium (20) and an earth ground (14) and configured to cause resonance with parasitic capacitance produced between a ground (6) the transmission means (3) and the earth ground (14), parasitic capacitance produced between the electric field transmission medium (20) and the ground (6) of the transmission means (3) and parasitic capacitance produced between the electric field transmission medium (20) and the earth ground (14), and a second reactance means (1) provided between an output of the transmission means (3) and the ground (6) of the transmission means (3) or between the transmission electrode (8) and the ground (6) of the transmission means (3).

Abstract: In a transceiver for inducing electric fields based on data to be transmitted in an electric field propagating medium and carrying out transmission and reception of data by using induced electric fields, having a transmission electrode and a transmission circuit, a transmission side switch is provided to disconnect the transmission circuit from the transmission electrode, when the transceiver is not in a transmission state in which the transmission circuit is supplying the transmission data to the transmission electrode.

Abstract: A transmitter (2) modulates information to be transmitted with an alternating-current signal having a predetermined frequency and includes a variable reactance section (16) which produces resonance with a stray capacitance (18) between a circuit ground (17) in the transmitter (2) and an earth ground (20) which strays from the earth ground (20) and a stray capacitance (19) between the human body (3) and the earth ground (20).

Abstract: On one pair of opposed side faces (1a, 1b) of electro-optic crystal (1), grooves (3a, 3b) are formed so as to make bottom faces of the grooves approach each other and make a distance between the bottom faces shorter than a predetermined distance, and the pair of electrodes (5a, 5b) are formed in the grooves (3a, 3b) so as to fill the grooves nearly completely.

Abstract: In a transceiver for inducing electric fields based on data to be transmitted in an electric field propagating medium and carrying out transmission and reception of data by using induced electric fields, having a transmission electrode and a transmission circuit, a transmission side switch is provided to disconnect the transmission circuit from the transmission electrode, when the transceiver is not in a transmission state in which the transmission circuit is supplying the transmission data to the transmission electrode.

Abstract: When a human hand (100) holds a transceiver (3a), the hand holds a bottom of an external wall surface and a side of the external wall surface of an insulating case (33). Therefore, a transmitting and receiving electrode (105) and an insulating film (107) cover not only the bottom of the external wall surface but also the side of the external wall surface of the insulating case (33). A first ground electrode (131), a second ground electrode (161), and a third ground electrode (163) are attached to upper portions of the internal wall surface of the insulating case (33) apart from the transmitting and receiving electrode (105). An insulating foam member (7a) is interposed between the insulating case (33) and a transceiver main body (30), and an insulating foam member (7b) is interposed between the transceiver main body (30) and a battery (6).