JP2011128120A - Doppler sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a Doppler sensor capable of suppressing erroneous determination. <P>SOLUTION: This Doppler sensor includes: a substrate 1 fixed to a mounting surface FS; and a reflector 3 fixed to the substrate 1 through a vibration-damping body 2 comprising an elastic material, for reflecting a radio wave. On the substrate 1, two transmitting/receiving circuits are mounted, for transmitting a radio wave to detection solid angles SR1, SR2 having mutually the same direction by transmitting antennas 11a, 11b respectively, and receiving the radio wave from the detection solid angles SR1, SR2, to thereby generate a Doppler signal having a frequency corresponding to changing speed of a distance between an object existing in the detection solid angles SR1, SR2 and the substrate 1. One detection solid angle SR2 is covered with the reflector 3. It is determined based on a differential signal between each Doppler signal outputted from the two transmitting/receiving circuits, whether a moving object (human body) exists within the other detection solid angle SR1 or not. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a Doppler sensor.

  Conventionally, for example, a radio wave (transmission wave) such as a millimeter wave is applied to a predetermined detection solid angle, and a radio wave (reflection wave) reflected within the detection solid angle is received and obtained from the transmission wave and the reflection wave. A Doppler sensor that determines the presence or absence of a moving object such as a human body using a Doppler signal is provided. This type of Doppler sensor is used to determine the presence or absence of a human body, for example, in an illumination system that switches on / off a light source according to the presence or absence of a human body (see, for example, Patent Document 1).

  Other sensors used to determine the presence or absence of a human body include, for example, a heat ray sensor that detects heat rays emitted from the human body, but the Doppler sensor can sense a human body at a long distance compared to a heat ray sensor Therefore, it is suitable for a usage pattern that can be attached to a ceiling in a building with a high ceiling.

JP 2009-204333 A

  However, when the Doppler sensor itself vibrates, a relative velocity is generated between the stationary object and the Doppler sensor, so that a Doppler shift also occurs in the reflected wave reflected by the stationary object. As a result, there is a possibility that an erroneous determination that a human body is present may occur even though the human body does not actually exist. As described above, the causes of vibration in the Doppler sensor itself include, for example, the operation of a machine such as a crane, a lift, and an elevator installed near the Doppler sensor, the wind pressure received by the mounting surface to which the Doppler sensor is fixed, and the like. Conceivable.

  The present invention has been made in view of the above-described reasons, and an object thereof is to provide a Doppler sensor that can suppress erroneous determination.

  According to a first aspect of the present invention, there is provided a substrate that is fixed to the mounting surface, an oscillation circuit that is mounted on the substrate and generates a transmission signal having a predetermined transmission frequency, and that is mounted on the substrate and the transmission signal is converted. The transmission wave is transmitted to a predetermined first detection solid angle, the first reflection wave reflected in the first detection solid angle is received, and the difference between the frequency of the transmission signal and the frequency of the first reflection wave A first transmission / reception circuit for generating an output including a first Doppler signal having a frequency of: a vibration damping body made of an elastic material and fixed to the substrate; a material reflecting a transmission wave; And transmitting the transmission wave mounted on the substrate and converted from the transmission signal to a predetermined second detection solid angle that is the same direction as the first detection solid angle and is covered by the reflector, The transmitted wave is reflected by the reflector within the second detection solid angle. A second transmission / reception circuit that receives the emitted second reflected wave and generates an output including a second Doppler signal having a frequency difference between the frequency of the transmission signal and the second reflected wave; and a first detection solid angle And a determination circuit that determines whether or not a moving object is present based on a difference signal between the first Doppler signal and the second Doppler signal.

  According to the present invention, the second Doppler signal and the first Doppler that reflect the speed of the reflector, which is estimated to be suppressed by the vibration due to being supported by the vibration damping body made of an elastic material, are suppressed. Since the difference signal from the signal is used for the determination, the influence due to the vibration of the substrate can be suppressed as compared with the case where the determination is performed based only on the first Doppler signal. It can be suppressed.

  According to a second aspect of the present invention, in the first aspect of the present invention, the surface of the reflector located within the second detection solid angle is a planar shape perpendicular to the central axis of the second detection solid angle.

  According to the first aspect of the present invention, the second Doppler signal reflecting the speed of the reflector, which is estimated to be suppressed more than the substrate by being supported via the vibration damping body made of an elastic material, Since the difference signal from the first Doppler signal is used, the influence of the vibration of the substrate is suppressed compared to the case where the determination is made based on only the first Doppler signal. Is suppressed.

It is sectional drawing which shows the principal part of embodiment of this invention. It is a block diagram which shows schematic structure same as the above. (A) (b) shows the principal part same as the above, respectively (a) is a perspective view, (b) is an exploded perspective view. (A)-(c) is explanatory drawing which respectively shows operation | movement same as the above, (a) shows the example of the waveform of a 1st Doppler signal, (b) shows the example of the waveform of a 2nd Doppler signal, c) shows an example of the waveform of the differential signal. (A) and (b) show the principal part of the modification example same as the above, respectively (a) is a perspective view, (b) is an exploded perspective view.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  In the present embodiment, as shown in FIG. 2, a human body as a moving object within a predetermined first detection solid angle SR1 (see FIG. 1) by radio waves transmitted and received using antennas 11a, 11b, 12a, and 12b (see FIG. 1). The lighting device 6 is controlled according to the determination result.

  In addition, as shown in FIGS. 1 and 3A and 3B, the present embodiment includes a flat plate-like substrate 1 that is fixed to a mounting surface FS such as a wall surface or a ceiling surface. On one surface of the substrate 1, a first transmitting antenna 11a, a first receiving antenna 12a, a second transmitting antenna 11b, and a second receiving antenna 12b, each of which is a planar antenna, are provided.

  Further, the substrate 1 is made of an elastic material and has a rectangular tube shape, which surrounds the second transmitting antenna 11b and the second receiving antenna 12b, and is fixed to the substrate 1 in such a manner that one opening is closed by the substrate 1. And a reflector 3 made of a material that reflects radio waves and fixed to the damping body 2 so as to close the other opening of the damping body 2. In other words, the reflector 3 is supported by the damping body 2 interposed between the substrate 1 and the reflector 3, and can be displaced with respect to the substrate 1 by elastic deformation of the damping body 2. The reflector 3 has a flat plate shape and is parallel to the substrate 1 in a state where the damping body 2 is not elastically deformed. As a material of the damping body 2, for example, a synthetic rubber marketed as a damping rubber can be used. Moreover, as a material of the reflector 3, metals, such as copper and iron, can be used, for example.

  Each of the antennas 11a, 11b, 12a, and 12b has a directivity that is axisymmetric with respect to a central axis that is parallel to the thickness direction of the substrate 1 (the left-right direction in FIG. 1). While the first detection solid angle SR1 for transmitting and receiving radio waves between the first transmitting antenna 11a and the first receiving antenna 12a is open, the second transmitting antenna 11b and the second receiving antenna 12b transmit and receive radio waves. The 2 detection solid angle SR2 is covered with the reflector 3. In the state where the damping body 2 is not elastically deformed, the reflector 3 is parallel to the substrate 1 as described above, so that the reflector 3 faces the second transmitting antenna 11b and the second receiving antenna 12b. The surface to be formed (that is, the surface located within the second detection solid angle SR2) is orthogonal to the central axis.

  In the present embodiment, a transmission signal that is an electrical signal having a predetermined frequency in the millimeter wave band is generated and input to each of the transmission antennas 11a and 11b, so that the same frequency as that of the transmission signal is transmitted from each of the transmission antennas 11a and 11b. An oscillation circuit 41 for transmitting a transmission wave composed of a plurality of radio waves (millimeter waves), and a difference frequency between the frequency of the radio wave (first reflected wave in the claims) received by the first receiving antenna 12a and the frequency of the transmission signal. A first signal processing circuit 42a for generating and outputting a first Doppler signal having a frequency of a difference between a frequency of a radio wave (second reflected wave in the claims) received by the second receiving antenna 12b and a frequency of a transmission signal; And a second signal processing circuit 42b for generating and outputting a second Doppler signal. That is, the first transmitting antenna 11a, the first receiving antenna 12a, and the first signal processing circuit 42a constitute the first transmitting / receiving circuit in the claims, and the second transmitting antenna 11b, the second receiving antenna 12b, and the second signal processing circuit. 42b constitutes the second transmitting / receiving circuit in the claims. In each of the signal processing circuits 42a and 42b, the Doppler signal is obtained by multiplying the combined waveform signal obtained by multiplying the reception signal generated by the reception of the radio wave by the reception antennas 12a and 12b and the transmission signal into an appropriate band filter. It is generated by passing. The oscillation circuit 41 and the signal processing circuits 42 a and 42 b are integrated in a one-chip signal processing integrated circuit 4, and the signal processing integrated circuit 4 is mounted on the substrate 1. Since the signal processing integrated circuit 4 as described above can be realized by a well-known technique, detailed illustration and description thereof are omitted.

  Here, the first Doppler signal has a frequency corresponding to the changing speed of the distance between the moving object existing in the first detection solid angle SR1 and the substrate 1. In addition, the second Doppler signal has a frequency corresponding to the changing speed of the distance between the moving object, that is, the reflector 3 and the substrate 1 existing in the second detection solid angle SR2.

  Furthermore, this embodiment determines whether or not a human body is present in the first detected solid angle SR1 based on a difference signal obtained by subtracting the second Doppler signal from the first Doppler signal, and the determination result Is provided with a determination circuit 5 that outputs a control signal corresponding to the illumination device 6. When the waveform of the first Doppler signal is as shown in FIG. 4A and the waveform of the second Doppler signal is as shown in FIG. 4B, the waveform of the difference signal is as shown in FIG. As shown in (c). Specifically, for example, the determination circuit 5 compares the amplitude of the difference signal with a predetermined determination threshold value, and determines that a human body exists if the amplitude of the difference signal is equal to or greater than the determination threshold value. If the amplitude of is less than the determination threshold, it is determined that there is no human body.

  The illuminating device 6 turns on an electric light source (not shown), and changes the light output of the electric light source or turns it on / off according to a control signal input from the determination circuit 5. Specifically, the determination circuit 5 inputs, for example, a control signal instructing the lighting device 6 to start lighting at the rated power of the electric light source when it is determined that a human body exists, and the human body does not exist. When the determination continues for a predetermined delay time, a control signal that instructs the electrical light source to turn off (or decrease in light output) is input to the illumination device 6. As the electric light source, for example, a light emitting diode or a discharge lamp can be used. The control signal may be an electric signal transmitted / received by wire or a wireless signal. In any case, the determination circuit 5 and the illuminating device 6 can be realized by well-known techniques, and thus detailed illustration and description thereof will be omitted.

  Here, when the substrate 1 itself vibrates in the thickness direction, the noise component corresponding to the vibration speed of the substrate 1 changes due to the change in the distance from the stationary object in the first detection solid angle SR1. Occurs in 1 Doppler signal. On the other hand, when the substrate 1 vibrates, an inertial force acts on the reflector 3, and the vibration damping body 2 interposed between the substrate 1 and the reflector 3 is elastically deformed. It becomes smaller than the amplitude of 1 vibration. Therefore, in the difference signal between the first Doppler signal and the second Doppler signal, the noise component is suppressed as compared with the first Doppler signal.

  In the present embodiment, whether or not a human body is present in the first detected solid angle SR1 is determined based on the difference signal between the first Doppler signal and the second Doppler signal, so that only the first Doppler signal is present. Compared to the case where the determination is used, erroneous determination due to the vibration of the substrate 1 as described above can be suppressed. Further, in addition to the noise component due to vibration as described above, if there is a noise component generated in the same phase in the first Doppler signal and the second Doppler signal, erroneous determination due to the noise component can be suppressed.

  Instead of providing the transmitting antennas 11a and 11b and the receiving antennas 12a and 12b separately as described above, as shown in FIGS. 5 (a) and 5 (b), the transmitting / receiving antennas 13a and 13b used for both transmission and reception are used. May be provided. In this case, the signal processing integrated circuit 4 includes a transmission state in which the transmission / reception antennas 13a and 13b function as the transmission antennas 11a and 11b by inputting the transmission signal from the oscillation circuit 41 to the transmission / reception antennas 13a and 13b, and the transmission / reception antenna. A circulator (not shown) that periodically and alternately switches the reception state in which the transmission / reception antennas 13a and 13b function as the reception antennas 12a and 12b by connecting the signal processing circuits 42a and 42b to the corresponding signal processing circuits 42a and 42b, Each pair of transmission / reception antennas 13a and 13b and signal processing circuits 42a and 42b is provided. The above circulators synchronize their operations with each other, and always make their operation states (transmission state or reception state) coincide with each other. Since the circulator as described above can be realized by a well-known technique, detailed illustration and description are omitted.

  Further, as described above, a three-dimensional antenna such as a horn antenna may be used instead of using a planar antenna as the antennas 11a, 11b, 12a, 12b, 13a, and 13b.

DESCRIPTION OF SYMBOLS 1 Board | substrate 2 Damping body 3 Reflector 5 Judgment circuit 11a 1st transmission antenna (a part of 1st transmission / reception circuit in a claim)
11b Second transmitting antenna (part of second transmitting / receiving circuit in claims)
12a First receiving antenna (part of the first transmitting / receiving circuit in the claims)
12b Second receiving antenna (part of second transmitting / receiving circuit in claims)
13a Transmission / reception antenna (part of first transmission / reception circuit in claims)
13b Transmitting and receiving antenna (part of second transmitting and receiving circuit in claims)
41 Oscillation circuit 42a First signal processing circuit (part of first transmission / reception circuit in claims)
42b Second signal processing circuit (part of second transmitting / receiving circuit in claims)
FS mounting surface SR1 first detection solid angle SR2 second detection solid angle

Claims (2)

A substrate fixed to the mounting surface;
An oscillation circuit mounted on the substrate and generating a transmission signal of a predetermined transmission frequency;
A transmission wave mounted on the substrate and having a transmission signal converted therein is transmitted to a predetermined first detection solid angle, and the transmission wave receives a first reflected wave reflected within the first detection solid angle, and transmits a transmission signal. A first transceiver circuit that generates an output including a first Doppler signal having a frequency that is a difference between the frequency of the first reflected wave and the frequency of the first reflected wave;
A damping body made of an elastic material and fixed to the substrate;
A reflector made of a material that reflects the transmitted wave and supported by the damping body;
The transmission wave mounted on the substrate and converted from the transmission signal is transmitted to a predetermined second detection solid angle that is in the same direction as the first detection solid angle and is covered by the reflector, and the transmission wave is second detected. A second transmission / reception circuit that receives a second reflected wave reflected by a reflector within a solid angle and generates an output including a second Doppler signal having a frequency that is the difference between the frequency of the transmission signal and the frequency of the second reflected wave When,
A Doppler sensor comprising: a determination circuit that determines whether a moving object is present within the first detected solid angle based on a difference signal between the first Doppler signal and the second Doppler signal.   2. The Doppler sensor according to claim 1, wherein a surface of the reflector located within the second detection solid angle has a planar shape orthogonal to the central axis of the second detection solid angle.

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