JP2008256473A - High-frequency sensor system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-frequency sensor system which more surely and quickly detects an object to be detected, and which is suitable as a non-contact operation switch. <P>SOLUTION: This sensor system is equipped with an oscillation circuit for generating transmission waves, a plurality of antenna electrodes formed on the surface of a substrate made up of a dielectric, to radiate the transmission waves and receive their reflected waves colliding with the object and returning, a grounding electrode formed at a position being opposed to the antenna electrodes with the substrate between, a detection circuit for detecting the received waves, and a direction control circuit for controlling the directions of the transmission waves to be radiated from the antenna electrodes. If a plane which is parallel with the direction of excitation of the antenna electrodes is defined as ϕ direction, the direction control circuit performs control so that the transmission waves are radiated sequentially in a plurality of directions, without their main beams overlapping in the ϕ direction. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a high-frequency sensor device suitable as a non-contact operation switch.

A high-frequency sensor device using the Doppler effect radiates a microwave radio wave as a transmission wave in front of the sensor, receives a reflected wave that the transmission wave collides with an object, and detects a moving object including a human body. be able to. In recent years, high-frequency sensor devices in which the radiation direction of a radio wave beam is fixed in one direction have been put into practical use for automatic doors, toilet bowl cleaning devices, and the like.
In addition, a high-frequency sensor device that uses a dielectric lens to switch the radiation direction of a radio wave beam has been proposed for an automobile collision prevention radar. This is because if the plane parallel to the excitation direction of the antenna electrode is the φ direction and the plane orthogonal to the excitation direction of the antenna electrode is the θ direction, fine steps (0.5 The radiation direction of the radio wave beam is switched at every step (for example, see Patent Document 1).

JP2004-037380

  When such a high-frequency sensor device is used as a non-contact operation switch for operating an actuator, for example, when the radiation direction of a radio wave beam is fixed in one direction, the flow control valve is Only when a human body is detected, the flow control valve opens and discharges water only when the human body is detected, and only the automatic faucet dedicated to hand washing used in the toilet can be used. On the other hand, if the radio beam can be radiated in multiple directions, for example, in the case of an automatic faucet, the applicable range is widened. If the radio beam is switched to two or more directions and a human body is detected in one direction, water is discharged, and in the other direction If a human body is detected and water is set in advance, the water can be used even in a state where no human body is detected, and can be used in a kitchen or a washroom.

However, if the radiation direction of the radio wave is too finely divided, it takes time until the radio wave radiation direction is switched and complete. Therefore, there is no problem if the person walks in the room, but in the case of the action of approaching or moving away from the hand, the frequency of switching the radiation direction of the radio wave is slow because of the relatively fast movement of 50 to 300 Hz. Then, it is not possible to accurately detect an approaching operation for a moment (100 mS or less). In addition, since the half-value angle is wide compared to the radio wave beam itself, the infrared sensor, etc., even if the radiation direction of the radio beam is finely switched within the range of the semi-near angle (for example, the direction (φ, θ) where the maximum radiation intensity is obtained) After a radio wave beam with a semi-close angle of ± 20 ° in the θ direction is first emitted at (0 °, 0 °), the maximum radiation intensity direction (φ, θ) is (0 °, 5 °), (0 ° , 10 °) radio wave beam is radiated) If the object to be detected is a human body (hand), the approaching direction will vary, so if the φ direction of the maximum radiation intensity direction of the radio wave beam is almost the same, the approaching direction in the θ direction Even if it is detected finely and an actuator or the like is operated correspondingly, the operability is extremely unstable.
The present invention has been made to solve the above problems, and an object of the present invention is to provide a high-frequency sensor device that can detect a detected object more reliably and quickly and is suitable as a non-contact operation switch.

In order to achieve the above object, an invention according to claim 1 is formed on an oscillation circuit that generates a transmission wave and a surface of a substrate made of a dielectric, and radiates the transmission wave and reflects a reflected wave by an object of the transmission wave. A plurality of antenna electrodes that are received as received waves, a ground electrode that is formed at a position facing the antenna electrodes via the substrate, a detection circuit that detects the received waves, and the transmitted waves that are radiated from the antenna electrodes A direction control circuit for controlling the direction of the antenna electrode, and assuming that the plane parallel to the excitation direction of the antenna electrode is the φ direction, the direction control circuit includes a plurality of main beams of the transmission wave without overlapping in the φ direction. A high-frequency sensor device that sequentially emits radiation in a direction.
Because the maximum radiation intensity direction of the first radio wave beam and the maximum radiation intensity direction of the next radio wave beam are not overlapped in the φ direction, it is possible to shorten the time until the radio wave radiation direction is switched, The approaching action of the hand for a moment (100 mS or less) can be accurately detected. The fact that the maximum radiation intensity direction of radio wave beams does not overlap here means that the maximum radiation intensity direction of the first radio wave beam emitted and the maximum radiation intensity direction of the next radio wave beam emitted are 10 degrees in the φ direction. That means different.

In order to achieve the above object, the invention according to claim 2 is characterized in that a plurality of the antenna electrodes not transmitting the transmission wave are arranged at symmetrical positions around the antenna electrode transmitting the transmission wave. And
A switch for changing the phase between antennas compared to a phased array type antenna that has a plurality of antenna electrodes through which high-frequency signals are propagated and appropriately changes the phase of the high-frequency signals propagated to each antenna electrode. In addition, the number of transmission lines can be reduced, and a stable detection performance can be obtained with little change in phase due to manufacturing variations, thereby achieving downsizing.

In order to achieve the above object, the invention according to claim 3 is characterized in that a switch capable of selecting either high-frequency signal passing or blocking is connected to the antenna electrode through which the transmission wave is not propagated. .
If a transistor or FET is used as a switch, the voltage at the base terminal or gate terminal insulated from the line through which the high-frequency signal is transmitted is controlled, and either the passage or blocking of the high-frequency signal is selected, the high-frequency signal is Even if it becomes 10 GHz or more, the phase of the antenna electrode is not affected, and the control circuit is simplified, so that radio wave scanning control is facilitated.

In order to achieve the above object, according to a fourth aspect of the present invention, the detection of the detected object is confirmed based on a signal from the detection circuit in any one of a plurality of directions in which the transmission waves are sequentially emitted. The control circuit is characterized in that the transmission wave is radiated in a direction in which detection of the detected object is confirmed.
It becomes possible to acquire detailed movement information in the direction in which the hand is approaching, and it is possible to operate the actuator based on the movement information instead of a simple ON / OFF switch. For example, in the case of an automatic door, it does not open when a person is walking in front of the door (for example, less than 50 Hz), and the door opens when the hand approaches the sensor device at a predetermined speed or more (for example, 50 Hz or more). Similarly, in the case of an automatic faucet, water is not discharged when a person is walking in front of a washbasin or sink, and water is discharged when a hand approaches the sensor device at a predetermined speed or higher.

In order to achieve the above object, according to a fifth aspect of the present invention, when the transmission wave is radiated in a direction in which detection of the detected object is determined by the direction control circuit, a frequency component is included in the signal from the detection circuit. Only the state that changes from the high side to the low side is output to the outside.
By outputting the speed and time at which the hand approaches, the actuator can be operated in an analog manner. For example, in the case of an automatic faucet, a small amount of water is discharged if the moving time is short even if the speed of approaching the hand is fast, and a large amount of water is discharged if the moving time is long even if the speed of approaching the hand is slow. The amount of water discharge can be changed only by such an operation of approaching.

  According to the present invention, it is possible to provide a high-frequency sensor device that can detect a detection target more reliably and quickly and is suitable as a non-contact operation switch.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram of a high-frequency sensor device according to an embodiment of the present invention. The high frequency sensor device includes a high frequency unit 10 and a control unit 20. The high frequency unit 10 includes an antenna 100 including a feeding element 102 and a parasitic element 104, and a high frequency circuit 120. The high-frequency circuit 120 is provided with an oscillation circuit 122 that generates a transmission wave 30 and a detection circuit 124 that extracts a Doppler signal from the reception wave 40.

  The transmission wave 30 radiated from the antenna 100 hits an object such as a human body to generate a reflected wave and is received by the feed element 102. The antenna 100 may be used for both transmission and reception, or transmission and reception may be separated. The frequencies of the transmission wave 30 that can be used in the high-frequency sensor device for human body detection are 10.525 and 24.15 GHz.

  When the object moves, a Doppler signal is output from the detection circuit 124 of the high frequency unit 10. This Doppler signal is input to the control determination circuit 206 via the amplifier 202 of the control unit 20. The control determination circuit 206 includes a comparator. After the output of the amplifier 202 is input, the control determination circuit 206 can perform switch control determination and output the output to the load control circuit 204.

  In addition, the control determination circuit 206 performs human body detection based on the output of the amplifier 202. The control determination circuit 206 also includes a direction control circuit that outputs a control signal for transitioning the radiation pattern 110 of the radio wave beam of the antenna 100. The radio wave radiation pattern 110 is sequentially radiated in a plurality of directions without overlapping in the φ direction. Let

  2A and 2B show the high-frequency unit 10 of the high-frequency sensor device of the present embodiment. FIG. 2A is a schematic plan view, and FIG. 2B is a schematic cross-sectional view along the line AA. The schematic plan view of FIG. 2A represents an example of the arrangement of microstrip antennas. The antenna 100 includes a feeding element 102 at a substantially center of a substrate 150 and a parasitic element 104 arranged in an X shape around the feeding element 102. The power feeding element 102 and the parasitic element 104 have patch electrodes provided on one main surface of the substrate 150. The other main surface of the substrate 150, that is, the back surface side of the patch electrode is a ground electrode.

  The feed element 102 is defined as a feed point P at a point shifted from the midpoint of the left-right symmetry axis. The parasitic element 104 includes 104a, 104b, 104c, and 104d. A transmission line 108 (including 108a, 108b, 108c, and 108d) extends in a direction parallel to the excitation direction and opposite to each other at approximately the center of one side of the parasitic element 104 that forms 90 degrees with the excitation direction. . A high-frequency switch 106 (including 106a, 106b, 106c, and 106d) is connected to the end of the transmission line 108, and each high-frequency switch 106 can be electrically controlled to be on or off.

  The high-frequency circuit 120 and the antenna 100 are fixed as shown in FIG. 2B, and the point P of the feed element 102 is connected to the oscillation circuit 122, and the antenna 100 is excited. Further, the received wave 40 from the power feeding element 102 is input to the detection circuit 124.

  FIG. 3 is a schematic diagram showing a radiation pattern in a plane (φ direction) parallel to the patch electrode from the antenna 100. The operation of obtaining the radio wave beam as shown in FIG. 3 by controlling on / off of the four high-frequency switches 106 will be described. First, when the high-frequency switch 106 is turned off, the transmission line 108 becomes a termination open line, and the phase and gain of the parasitic element 104 can be set to a positive state. When the high-frequency switch 106 is turned on, the transmission line 108 is short-circuited at the termination, and the phase of the parasitic element 104 can be negative or the gain can be negative.

  In the case of the angular arrangement according to the antenna schematic plan view of FIG. 2A, the state of the high-frequency switch corresponding to each beam A to H of FIG. 3 is shown in (Table 1). SW1 is 106a, SW2 is 106b, SW3 is 106c, and SW4 is 106d. For example, the beam B represents a radiation pattern in which only SW1 is turned off and the remaining three high-frequency switches are turned on. The gain maximum direction of the beam 111 is substantially 45 degrees, and the 3 dB gain is lower than the maximum in the φ direction. The half-value angle is expressed by θ. Similarly, for the D, F, and H beams, only one high-frequency switch is turned off, and the beam gain maximum direction is directed to 135, 225, and 315 degrees.

For example, the beam A is maximized in the 0 degree direction by turning off SW1 and SW4 and turning on the other two. It can also be said that the beam A is synthesized by the beam B and the beam H. Similarly, the gains of the C, E, and G beams are maximized in the directions of 90, 180, and 270 degrees by turning off the two high-frequency switches. That is, in the case of FIG. 3, eight radiation patterns can be selected.
According to this embodiment, using such an antenna, two directions of 0, 180 degrees or 90, 270 degrees, three directions of 0, 90, 180 degrees or 0, 270, 180 degrees, 0, 90, 180, Radio waves are sequentially emitted and scanned at a wide interval with four directions of 270 degrees. By doing so, the maximum radiation intensity direction of the first radio wave beam and the maximum radiation intensity direction of the next radio wave beam to be radiated do not overlap in the φ direction. The time taken to determine the approaching direction of the human body (hand) can be shortened, and the approaching action of the hand for a moment (100 mS or less) can be detected with high accuracy. In particular, in the two directions of 0, 180 degrees or 90, 270 degrees, the half-value angle in the φ direction does not overlap, so that the approaching action of the hand can be detected with higher accuracy. When the detection of the human body (hand) is confirmed in any direction, the movement information in the direction in which the human body (hand) approaches is acquired in detail by fixing and radiating the radio wave beam in the direction in which the detection is confirmed. Therefore, the actuator can be operated based on movement information instead of a simple ON / OFF switch.

  In the present embodiment, an example of radio wave scanning in which a feed element and a parasitic element are provided as antenna electrodes and the radiation direction of the radio beam is switched by appropriately turning on / off a switch connected to the parasitic element is shown. A plurality of power supply elements that propagate high-frequency signals from the circuit through the transmission line are provided, and the phase of the high-frequency signal that propagates to each power supply element is changed by appropriately turning on and off the switch connected to the intermediate path of the transmission line. It is also possible to realize a radio wave scanning form in which the radiation direction of the radio wave beam is switched.

  4A and 4B are diagrams for explaining the operation of the high-frequency switch 106 of the present invention. FIG. 4A is an enlarged view of the vicinity of the high-frequency switch 106a, and FIG. 4B is an equivalent circuit thereof. For example, when a high electron mobility transistor (HEMT) or a GaAs MESFET (Metal Semiconductor Field Effect Transistor) is used as the high frequency switch 106a, the source terminal and the drain terminal can be switched on or off by a control voltage applied to the gate terminal. .

  The terminal portion of the transmission line 108a is connected to the drain terminal 161a, and the source terminal 162a is connected to the ground electrode 167 on the back surface of the substrate through the conductive pattern 163a and the through hole 164a. When the gate terminal 165a is controlled by the gate voltage to conduct between the source terminal 162a and the drain terminal 161a and the high frequency switch 106a is turned on, the transmission line 108a acts as a terminal short circuit line. Further, when the gate voltage is controlled so that the drain terminal 161a and the source terminal 162a are not conductive and the high-frequency switch 106a is turned off, the transmission line 108a acts as an open termination line of length J.

The parasitic element 104 with the high-frequency switch 106 turned off can be a waveguide having a positive phase and a positive gain, and the parasitic element 104 with the high-frequency switch 106 turned on is a reflector having a negative phase or a negative gain. And can. A beam shown in (Table 1) can be realized by combining such parasitic elements 104.
Therefore, in order to change the phase between the antennas compared to a phased array type antenna that has a plurality of antenna electrodes through which high-frequency signals are propagated and appropriately changes the phase of the high-frequency signals propagated to each antenna electrode. Therefore, the number of switches and transmission lines can be reduced, the change in phase due to manufacturing variations is small, and stable detection performance can be obtained, and the size can be reduced. Further, if the voltage of the base terminal and the gate terminal insulated from the line through which the high-frequency signal is transmitted is controlled and either one of the high-frequency signal passing or blocking is selected, the antenna can be used even if the high-frequency signal becomes 10 GHz or more. Since the phase of the electrode is not affected and the control circuit is simplified, radio wave scanning control is facilitated.

  By using the high-frequency sensor device of this embodiment, it is possible to accurately and quickly control an automatic door, a remote control device, a toilet cleaning device, a lighting device, and the like without contact.

  The embodiments of the present invention have been described above with reference to the drawings. However, the present invention is not limited to these embodiments. Even if a person skilled in the art changes the design of the oscillation circuit, the detection circuit, the control determination circuit, the antenna, the determination means, the detection method, etc. constituting the high-frequency sensor device, the present invention can be used without departing from the spirit of the present invention. Included in the range.

It is a block diagram of the high frequency sensor apparatus concerning an embodiment of the invention. It is a schematic diagram of the high frequency part which comprises a high frequency sensor apparatus. It is a figure showing the radiation pattern of a radio wave beam. It is a figure explaining a high frequency switch.

Explanation of symbols

  6 persons, 30 transmission waves, 40 reception waves, 122 oscillation circuit, 100 antenna, 102 feeding element, 104 parasitic element, 111 beam, 124 detection circuit, 206 control judgment circuit

Claims (5)

An oscillation circuit for generating a transmission wave;
A plurality of antenna electrodes formed on the surface of a substrate made of a dielectric material for receiving the reflected wave that radiates the transmitted wave and the transmitted wave collides with an object and returns;
A ground electrode formed at a position facing the antenna electrode via the substrate;
A detection circuit for detecting the received wave;
A direction control circuit for controlling the direction of the transmitted wave radiated from the antenna electrode;
With
When a plane parallel to the excitation direction of the antenna electrode is a φ direction, the direction control circuit causes the main beam of the transmission wave to be sequentially emitted in a plurality of directions without overlapping in the φ direction. .   The high-frequency sensor device according to claim 2, wherein a plurality of the antenna electrodes that do not transmit the transmission wave are arranged at symmetrical positions with respect to the antenna electrode that transmits the transmission wave.   The high-frequency sensor device according to claim 1, wherein a switch capable of selecting either high-frequency signal passing or blocking is connected to the antenna electrode through which the transmission wave is not propagated.   When the detection of the detected object is determined based on a signal from the detection circuit in any of a plurality of directions in which the transmission waves are sequentially emitted, the direction control circuit transmits the transmission in the direction in which the detection of the detected object is determined. The high-frequency sensor device according to any one of claims 1 to 3, wherein a wave is radiated.   When the transmission wave is radiated in the direction in which detection of the detected object is determined by the direction control circuit, only the state in which the frequency component of the signal from the detection circuit changes from the high side to the low side is output to the outside. The high-frequency sensor device according to claim 4.

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