JP6979474B2 - measuring device - Google Patents

Description

The present invention relates to the technical field of a measuring device that acquires information about an object by using electromagnetic waves.

In recent years, research and development of terahertz wave imaging and radar have become active, and there are high expectations for their application to, for example, non-destructive inspection and sensing. Generally, an oscillating element and a detecting element are used separately for oscillation and detection of a terahertz wave. On the other hand, for example, Patent Document 1 discloses a technique in which one element (resonant tunnel diode) is shared as an oscillator that oscillates a terahertz wave and a detector that detects the terahertz wave.

Special Table 2014-517620 Gazette

In the technique described in Patent Document 1 described above, a variable resistor is used for switching between oscillation and detection. In this case, since the response speed of the circuit becomes extremely slow, it is very difficult to detect the terahertz wave oscillated by itself. Therefore, the technique described in Patent Document 1 performs all terahertz wave oscillation and detection for measurement with one element even if one element can be switched and functioned as an oscillator and a detector. It has a technical problem that it cannot be done.

The above-mentioned problems are given as an example of the problems to be solved by the present invention. An object of the present invention is to provide a measuring device capable of using one element for both oscillation and reception.

The measuring device that solves the above problems is a transmission / reception unit that performs an irradiation operation of irradiating an object with an electromagnetic wave and a reception operation of receiving the electromagnetic wave reflected by the object, and an electromagnetic wave received by the transmission / reception unit. The detection unit that detects information, the control unit that causes the transmission / reception unit to perform either the irradiation operation or the reception operation, and the transmission / reception unit side that performs the irradiation operation when the control unit performs the irradiation operation. It is provided with an output unit that outputs a signal for irradiating electromagnetic waves and outputs a signal input from the transmission / reception unit side to the detection unit side when the control unit performs the reception operation.

It is a schematic block diagram which shows the structure of the measuring apparatus which concerns on Example. It is a schematic block diagram which shows the structure of the measuring apparatus which concerns on 1st modification. It is a schematic block diagram which shows the structure of the measuring apparatus which concerns on 2nd modification. It is a time chart which shows various signals at the time of operation of the measuring apparatus which concerns on Example.

<1>
The measuring device according to the present embodiment has a transmission / reception unit that performs an irradiation operation of irradiating an object with an electromagnetic wave and a reception operation of receiving the electromagnetic wave reflected by the object, and an electromagnetic wave received by the transmission / reception unit. The detection unit that detects information, the control unit that causes the transmission / reception unit to perform either the irradiation operation or the reception operation, and the transmission / reception unit side that performs the irradiation operation when the control unit performs the irradiation operation. It is provided with an output unit that outputs a signal for irradiating electromagnetic waves and outputs a signal input from the transmission / reception unit side to the detection unit side when the control unit performs the reception operation.

According to the measuring device of the present embodiment, during the operation, the electromagnetic wave is emitted from the transmission / reception unit that performs the irradiation operation toward the object. The "electromagnetic wave" here is an electromagnetic wave that can acquire information about an object by reflection measurement, and a terahertz wave can be mentioned as an example. The terahertz wave is an electromagnetic wave belonging to a frequency region (that is, a terahertz region) around 1 terahertz (1 THz = 10 ^{12 Hz).}

The electromagnetic wave radiated to the object is reflected by the object and received by the transmission / reception unit that performs the reception operation. That is, in the present embodiment, the electromagnetic wave irradiation operation and the reception operation are performed by one transmission / reception unit. The transmission / reception unit is configured as, for example, a resonance tunneling diode (RTD) or the like.

The reception result in the transmission / reception unit is output to the detection unit by the operation of the output unit described later. The detection unit acquires the amplitude, frequency, phase, time waveform, etc. of the signal indicating the received electromagnetic wave. Then, the detection unit performs arithmetic processing on the acquired various information and acquires information about the object. The detection unit can perform imaging of an object and acquisition of distance information based on, for example, the intensity and time waveform of the received electromagnetic wave.

The irradiation operation and the reception operation of the transmission / reception unit are switched by the control unit. Specifically, when the control unit causes the transmission / reception unit to perform an irradiation operation, a signal for irradiating the transmission / reception unit with an electromagnetic wave is output from the output unit. The "transmission / reception unit side" here means a portion located on the transmission / reception unit side when viewed from the output unit, and "outputting a signal to the transmission / reception unit side" means directly to the transmission / reception unit. This includes not only the case of outputting a signal but also the case of outputting a signal to a portion located between the output unit and the transmission / reception unit. Further, the "signal for irradiating the electromagnetic wave" may be a signal that outputs the control signal or the like output by the control unit to the transmission / reception unit side as it is, or may be a signal newly generated by the output unit. ..

On the other hand, when the control unit causes the transmission / reception unit to perform the reception operation, the output unit outputs the signal input from the transmission / reception unit side to the detection unit side. The "detection unit side" here means a portion located on the detection unit side when viewed from the output unit, and "outputting a signal to the detection unit side" means directly to the detection unit. This includes not only the case of outputting a signal but also the case of outputting a signal to a portion located between the output unit and the detection unit. Further, the "signal input from the transmission / reception unit side" is a signal corresponding to the received electromagnetic wave, for example, a signal indicating whether or not the electromagnetic wave is received or a signal indicating the reception intensity of the electromagnetic wave.

As described above, various signals are output from the output unit depending on which operation the control signal causes the transmission / reception unit to perform. This makes it possible to suitably switch between the irradiation operation and the reception operation of the transmission / reception unit. The output unit may be configured as an electronic switch such as a circulator, an isolator, or a MOSFET. According to such an output unit, the irradiation operation and the reception operation can be switched at an extremely high speed, so that the electromagnetic wave oscillated by the transmission / reception unit can be received by the transmission / reception unit itself.

As described above, according to the measuring device according to the present embodiment, the electromagnetic wave can be oscillated and received by one transmitting / receiving unit without separately providing the generating element for oscillating the electromagnetic wave and the receiving element for receiving the electromagnetic wave. .. This makes it possible to measure the reflection of electromagnetic waves with a relatively simple measurement system. In addition, since the oscillated electromagnetic wave has the largest component that is specularly reflected by the object and returned to the source, the utilization efficiency of the electromagnetic wave is also improved.

<2>
In one aspect of the measuring device according to the present embodiment, the control unit outputs a control signal indicating whether the transmission / reception unit should perform the irradiation operation or the reception operation, and the output unit outputs the control signal. Is a signal value for which the irradiation operation should be performed, a signal for irradiating the electromagnetic wave to the transmission / reception unit side is output, and when the control signal is a value for performing the reception operation, the detection unit. The signal input from the transmission / reception unit side is output to the side.

According to this aspect, various signals are output from the output unit according to the control signal output from the control unit. Specifically, when the control signal output from the control unit is a value for performing the irradiation operation, the output unit outputs a signal for irradiating the transmission / reception unit side with the electromagnetic wave. On the other hand, when the control signal output from the control unit is a value for performing the reception operation, the output unit outputs the signal input from the transmission / reception unit side to the detection unit side.

As described above, when the output unit outputs various signals according to the control signal, it is possible to suitably switch between the irradiation operation and the reception operation of the transmission / reception unit.

<3>
In the embodiment in which the control unit described above outputs a control signal, the control unit may output a pulse signal as the control signal.

With this configuration, it is possible to suitably switch between the irradiation operation and the reception operation of the transmission / reception unit according to the level of the pulse signal output by the control unit.

<4>
Alternatively, in the embodiment in which the control unit outputs a control signal, the transmission / reception unit is further provided with a voltage application unit that applies an irradiation voltage for irradiating the electromagnetic wave, and the output unit performs the irradiation operation by the control signal. When it is a power value, a signal for applying the irradiation voltage to the voltage application unit may be output.

With this configuration, when the control signal is a value that should perform the irradiation operation, the irradiation voltage is applied to the transmission / reception unit by the voltage application unit. This makes it possible to reliably irradiate electromagnetic waves from the transmission / reception unit.

The operation and other gains of the measuring device according to the present embodiment will be described in more detail in the following examples.

Hereinafter, examples of the present invention will be described in detail with reference to the drawings.

<Device configuration>
First, the configuration of the measuring device of this embodiment will be described with reference to FIG. 1. Here, FIG. 1 is a schematic configuration diagram showing the configuration of the measuring device according to the embodiment.

In FIG. 1, the measuring device 10 according to the present embodiment can irradiate the object 200 with a terahertz wave and receive the terahertz wave reflected by the object 200. The terahertz wave is an electromagnetic wave belonging to a frequency region (that is, a terahertz region) around 1 terahertz (1 THz = 10 ^{12 Hz).} The terahertz region is a frequency domain that has both straightness of light and transparency of electromagnetic waves.

The measuring device 10 according to the present embodiment includes a waveform generator 110, a circulator 120, a bias rate 130, a DC voltage supply unit 140, a resonance tunnel diode 150, and a detector 160.

The waveform generator 110 is a specific example of the “control unit” and outputs a control signal for switching the operation of the resonance tunnel diode 150. Specifically, the waveform generator 110 outputs a control signal indicating whether the resonance tunnel diode 150 should perform an oscillating operation for oscillating a terahertz wave or a receiving operation for receiving the terahertz wave. The control signal output from the waveform generator 110 is, for example, a pulse, a pulse train, a square wave, or the like, and its amplitude is a peak to peak value, which is a value that is the difference between the oscillation voltage and the detection voltage of the resonance tunnel diode 150. Is set to.

The circulator 120 is a specific example of the "output unit", and switches the transmission path of the signal based on the control signal output from the control unit. Specifically, the circulator 120 outputs the control signal to the bias tee 130 when the control signal is at a level corresponding to the oscillation operation. Further, the circulator 120 outputs the signal input from the bias tee 130 to the detector 160 when the signal is at a level corresponding to the reception operation.

The bias tee 130 is a specific example of the "voltage application unit", and adds the DC voltage (that is, the voltage for irradiation) supplied from the DC voltage supply unit 140 to the control signal input from the circulator 120. Then, it is output to the resonance tunnel diode 150. Further, the bias tee 130 outputs the AC component of the signal output from the resonance tunnel diode 150 (that is, the reception signal of the terahertz wave) to the circulator 120.

The resonance tunnel diode 150 is a specific example of the “transmission / reception unit”, and can selectively perform an oscillation operation for oscillating a terahertz wave and a reception operation for receiving a terahertz wave. Specifically, the resonance tunnel diode 150 has a voltage region for oscillating operation and a voltage region for receiving operation separately, and oscillating operation and oscillating operation according to a control signal output from the waveform generator 110. The reception operation can be switched. The resonance tunnel diode 150 during the oscillation operation irradiates the object 200 with a terahertz wave. On the other hand, the resonance tunnel diode 150 during the reception operation outputs the received signal corresponding to the received terahertz wave to the bias tee 130.

The terahertz wave irradiated from the resonance tunnel diode 150 may be guided to the object 200 via various optical members. Specifically, the terahertz wave is irradiated to the object 200 through, for example, a collimating lens that makes the terahertz wave parallel light, a condensing lens that concentrates the terahertz wave on the object, a curved mirror, or the like. In this case, the terahertz wave reflected by the object 200 is also guided to the resonance tunnel diode 150 via various optical members. The detector 160 has an amplitude, frequency, phase, time waveform, etc. of the signal input from the circulator 120. To get out. Further, the detector 160 executes various arithmetic processes on the acquired information to acquire information about the object 200. The detector 160 is capable of generating, for example, an imaging image of the object 200 and acquiring the position information of the object 200 as information about the object.

<Modification example>
Next, the configuration of the terahertz wave measuring device according to the modified example will be described with reference to FIGS. 2 and 3. Here, FIG. 2 is a schematic configuration diagram showing the configuration of the measuring device according to the first modification. Further, FIG. 3 is a schematic configuration diagram showing the configuration of the measuring device according to the second modification. In FIG. 2, the measuring device 10b according to the first modification is replaced with the circulator (see FIG. 1) according to the present embodiment. The isolator 121 is provided. The isolator 121 is configured to absorb the reflected wave by terminating one terminal of the circulator 120.

Like the circulator 120, the isolator 121 switches the signal transmission path based on the control signal output from the waveform generator 110. Specifically, the isolator 121 outputs the control signal to the bias tee 130 when the control signal is at a level corresponding to the oscillation operation. Further, the isolator 121 absorbs (that is, does not output) the signal input from the bias tee 130 when the control signal is at a level corresponding to the reception operation. When the control signal is at a level corresponding to the reception operation, the signal between the isolator 121 and the bias tee 130 is read by the detector 160 having a high impedance.

In FIG. 3, the measuring device 10c according to the second modification is configured to include an electronic switch 122 in place of the circulator (see FIG. 1) according to the present embodiment. The electronic switch 122 is configured to be switchable on and off by a control signal from the waveform generator 110. In other words, the waveform generator 110 according to the second modification outputs the drive voltage of the electronic switch 122 as a control signal. Further, the electronic switch 122 is connected to a second DC voltage supply unit 170 that supplies a DC voltage instead of the control signal.

Like the circulator 120 and the isolator 121, the electronic switch 122 switches the transmission path of the signal based on the control signal output from the waveform generator 110. Specifically, the electronic switch 122 is turned on when the control signal is at a level corresponding to the oscillation operation, and connects the second DC voltage supply unit 170 and the bias tee 130. Further, the electronic switch 122 is turned off when the control signal is at a level corresponding to the reception operation, and connects the bias tee 130 and the detector 160.

As described above, the same operation as that of the measuring device 10 according to the present embodiment can be realized by the measuring devices 10b and 10c according to the modified example.

<Operation explanation>
Next, the operation of the measuring device 10 according to the present embodiment will be specifically described with reference to FIG. Here, FIG. 4 is a time chart showing various signals during operation of the terahertz wave measuring device according to the embodiment.

In FIG. 4, a control signal having an amplitude Vmod is output from the waveform generator 110 during the irradiation operation of the measuring device 10 according to the present embodiment. Here, since the voltage Vmod is a voltage corresponding to the irradiation operation, it is guided to the bias tee 130 by the circulator 120.

Then, in the bias tee 130, the voltage Vdet for irradiating the terahertz wave is added to the Vmod, and the voltage Vosc is output to the resonance tunnel diode 150. The resonant tunneling diode 150 to which the voltage Vosc is applied irradiates the object 200 with a terahertz wave.

On the other hand, during the reception operation of the measuring device 10 according to this embodiment, the waveform generator 110 does not output the control signal of the amplitude Vmod. In other words, the measuring device 10 is in the reception standby state unless the waveform generator 110 outputs a control signal having an amplitude Vmod.

When a terahertz wave is received by the resonance tunnel diode 150 during the reception operation, the reception signal Vsig is output from the resonance tunnel diode 150 to the bias tee 130. Biasty 130 removes the DC component from Vsig and outputs only the AC component to the circulator 120. Since the control signal Vmod is not output from the waveform signal, the circulator 120 outputs the AC component output from the bias tee 130 to the detector 160.

As described above, according to the measuring device 10 according to the present embodiment, oscillation and reception can be performed by one element without separately providing a terahertz wave generating element and a receiving element. This makes it possible to measure the reflection of terahertz waves with a relatively simple measurement system. Further, since the oscillated terahertz wave has the largest component that is specularly reflected by the object 200 and returned to the source, the utilization efficiency of the terahertz wave is also improved.

The present invention is not limited to the above-described embodiment, and can be appropriately modified within the scope of the claims and within the scope not contrary to the gist or idea of the invention that can be read from the entire specification. It is also included in the technical scope of the present invention.

10 Measuring device 110 Wave generator 120 Circulator 121 Isolator 122 Electronic switch 130 Bias Tee 140 DC voltage supply unit 150 Resonant tunnel diode 160 Detector 170 Second DC voltage supply unit 200 Object

Claims (5)

A first electromagnetic wave generated by the one active element, including one active element capable of generating an electromagnetic wave when a predetermined signal is input and receiving an electromagnetic wave incident from the outside when the predetermined signal is not input. a transceiver irradiating operation for irradiating the object and that the receiving operation of the first electromagnetic wave is received by the second electromagnetic wave reflected by the object performs,
A detection unit that detects information on the second electromagnetic wave received by the transmission / reception unit, and a detection unit.
A control unit that causes the transmission / reception unit to perform either the irradiation operation or the reception operation.
When the control unit performs the irradiation operation, a first signal for causing the one active element to input the predetermined signal is output to the transmission / reception unit side, and the control unit performs the reception operation. A measuring device including an output unit that outputs a reception signal of the second electromagnetic wave input from the transmission / reception unit to the detection unit side. The measuring device according to claim 1, wherein the output unit is composed of a circulator, an isolator, or an electronic switch. The measuring device according to claim 1 or 2, wherein the control unit outputs a pulse signal as a control signal for switching between the irradiation operation and the reception operation of the transmission / reception unit. The one active element is further provided with a voltage application unit that applies an irradiation voltage as the predetermined signal.
The output unit outputs the control signal to the voltage application unit when a signal for selecting the irradiation operation of the transmission / reception unit is output as the control signal.
The measuring device according to claim 3. The measuring device according to any one of claims 1 to 4, wherein the one active element is a resonance tunnel diode.

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