Droplet diffusion prevention device

Abstract

To provide a droplet diffusion prevention device that can be also used for other than preventing the diffusion of droplets.SOLUTION: A droplet diffusion prevention device 1 includes: a transparent planar member 10 for preventing diffusion of droplets; a proximity sensor having an antenna 21 provided on the planar member 10 and a detection unit that detects an object according to a change in at least one of a transmission signal and a reception signal of the antenna 21; and an output unit that performs output corresponding to the detection of the object by the detection unit. In this way, the droplet diffusion prevention device 1 can detect visitors or the like, and the device for preventing the diffusion of droplets can be effectively used.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a droplet diffusion prevention device capable of detecting an object. [Background technology]

[0002] In recent years, the novel coronavirus disease (COVID-19) has become widespread, and in order to prevent the spread of infection through droplets, droplet prevention devices made of transparent acrylic panels or transparent vinyl sheets are increasingly being used in stores, workplaces, and other places (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Utility Model Registration No. 3228226 Summary of the Invention [Problem to be solved by the invention]

[0004] There has been a demand for more effective use of devices that prevent the spread of such droplets.

[0005] The present invention has been made in response to the above circumstances, and aims to provide a droplet diffusion prevention device that can be used to prevent the diffusion of droplets for purposes other than droplet diffusion. [Means for solving the problem]

[0006] In order to achieve the above-mentioned objective, a droplet diffusion prevention device according to one embodiment of the present invention comprises a transparent planar member for preventing droplet diffusion, an antenna provided on the planar member, and a proximity sensor having a detection unit that detects an object in response to changes in at least one of the antenna's transmitted signal and received signal. With this configuration, for example, a person can be detected using the antenna provided on the transparent planar member. Therefore, for example, at a reception desk or a cash register, a visitor or customer can be detected and customer service can be provided accordingly.

[0007] In addition, in the droplet diffusion prevention device according to one aspect of the present invention, the proximity sensor may have two or more antennas provided on the planar member, and the detection unit may detect an object for each of the two or more antennas. With this configuration, two or more antennas can each detect an object, making it possible to determine, for example, the number of visitors and whether the visitors are adults or children.

[0008] In addition, in the droplet diffusion prevention device according to one aspect of the present invention, the detection unit may also detect the distance to the object to be detected. With this configuration, it is possible to detect, for example, whether a visitor is in the immediate vicinity or at some distance.

[0009] In the droplet diffusion prevention device according to one aspect of the present invention, the antenna may be made of a transparent conductor. This configuration ensures that the antenna does not obstruct vision, and for example, even when a customer and an employee are facing each other across a planar member, neither of them feels uncomfortable.

[0010] In addition, the droplet diffusion prevention device according to one aspect of the present invention may further include an output section that performs output in response to detection of an object by the detection section. With this configuration, for example, an employee can be notified that a customer has arrived.

[0011] In addition, in the droplet diffusion prevention device according to one aspect of the present invention, the proximity sensor may detect objects on both surfaces of the planar member. With this configuration, it is possible to distinguish, for example, whether a customer arrives when an employee is present on one side of the planar member, or whether a customer arrives when no employee is present, and to output accordingly. Effect of the Invention

[0012] According to an embodiment of the droplet diffusion prevention device of the present invention, the device for preventing droplet diffusion can also detect objects, for example, visitors. [Brief description of the drawings]

[0013] [Figure 1] 1 is a schematic diagram showing a droplet diffusion prevention device according to an embodiment of the present invention; [Diagram 2] FIG. 13 is a schematic diagram showing another example of the droplet diffusion prevention device according to the embodiment; [Figure 3A] FIG. 2 is a block diagram showing a configuration of a proximity sensor in the embodiment; [Figure 3B] FIG. 11 is a block diagram showing another example of the configuration of the proximity sensor according to the embodiment. [Figure 4] FIG. 13 is a schematic diagram showing another example of the droplet diffusion prevention device according to the embodiment; [Diagram 5] FIG. 2 shows an example of an antenna according to the embodiment. [Figure 6] FIG. 4 is a diagram showing an example of a change in detection voltage according to the frequency of a high-frequency signal in the embodiment; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The droplet diffusion prevention device according to the present invention will be described below using an embodiment. In the following embodiments, components with the same reference numerals are the same or equivalent, and repeated description may be omitted. The droplet diffusion prevention device according to this embodiment is capable of detecting a detection target such as a person by using a proximity sensor.

[0015] Fig. 1 is a schematic diagram showing a droplet diffusion prevention device 1 according to the present embodiment. Fig. 2 is a schematic diagram showing another example of the droplet diffusion prevention device 1. Fig. 3A is a functional block diagram showing a proximity sensor 20 and an output unit 30 included in the droplet diffusion prevention device 1.

[0016] The droplet diffusion prevention device 1 includes a transparent sheet member 10 for preventing droplet diffusion, a proximity sensor 20 having an antenna 21 provided on the sheet member 10, and an output unit 30 that performs output in response to detection of an object by the proximity sensor 20. Preventing droplet diffusion may mean, for example, preventing droplets from touching a person or preventing droplets from diffusing in the air in order to prevent droplet infection.

[0017] The planar member 10 may be, for example, a transparent plate-like member for preventing droplet diffusion, as shown in Fig. 1. In this case, the planar member 10 is made of a transparent resin plate, such as an acrylic plate or a PET resin plate, and usually has enough strength to maintain a plate-like shape. The planar member 10 in the form of a flat plate may be erected by a stand 11 to form the droplet diffusion prevention device 1 as a partition plate. Such a planar member 10 as a partition plate may be used, for example, at a reception desk or on a table in a restaurant.

[0018] The planar member 10 may also be a transparent sheet suspended from above, as shown in FIG. 2. In this case, the planar member 10 is made of a transparent resin sheet such as a vinyl sheet and is usually flexible enough to be folded or rolled up. The planar member 10 may also be a banner, curtain, hanging sheet, or the like. Such a curtain-like planar member 10 may be suspended above a cash register 5 in a store, as shown in FIG. 2, and may be used to separate an employee at the cash register 6 from a customer purchasing products.

[0019] The proximity sensor 20 is a sensor for detecting an object, and includes an antenna 21 and a detection unit 22. In this embodiment, the case where the object to be detected is a human body, i.e., a human being, will be mainly described, but it goes without saying that the object to be detected is not limited to a human body.

[0020] The antenna 21 is provided on the planar member 10. The antenna 21 may be provided, for example, on the surface of the planar member 10, or may be provided inside the planar member 10. In the latter case, for example, the planar member 10 incorporating the antenna 21 may be configured by sandwiching the linear or planar antenna 21 between two transparent flat plates or sheets. The antenna 21 is not particularly limited, and may be, for example, a linear dipole antenna or a planar patch antenna. In this embodiment, the case where the antenna 21 is a patch antenna as shown in FIG. 1 etc. will be mainly described.

[0021] The antenna 21 may be, for example, opaque or transparent. From the viewpoint of not interfering with vision, it is preferable that the antenna 21 is transparent. The transparent antenna 21 may be made of, for example, a transparent conductor. The transparent conductor is not particularly limited, and may be, for example, ITO (Indium Tin Oxide), zinc oxide, graphene, silver nanowires, or the like.

[0022] 1 and 2, the antenna 21 is connected to the detection unit 3 by a wiring 12. The portion of the wiring 12 that is provided on the planar member 10 may be made of a transparent conductor, for example, similar to the antenna 21. The detection unit 3 may have a detection section 22 and an output section 30, as shown in FIG. 3A.

[0023] The detection unit 22 detects an object in response to a change in at least one of the transmission signal and the reception signal of the antenna 21, and as shown in Fig. 3A, has an oscillator 41, a change output unit 42, and an object detection unit 43. In this embodiment, the case where the detection unit 22 detects an object in response to a change in the transmission signal of the antenna 21 will be mainly described, and other cases will be described later.

[0024] The oscillator 41 generates a high-frequency signal. The oscillator 41 may generate a high-frequency signal of a constant frequency, or may generate a high-frequency signal in a predetermined frequency range while continuously changing the frequency. In the latter case, the oscillator 41 may be a sweep oscillator. The frequency of the high-frequency signal is determined according to how close an object to be detected needs to be to the antenna 21 in order to be detected. The higher the frequency (i.e., the shorter the wavelength), the closer the object detection range to the antenna 21 will be. Although not particularly limited, the frequency of the high-frequency signal may be, for example, 100 MHz or more, or 1 GHz or more. The frequency of the high-frequency signal may be, for example, 50 GHz or less, 30 GHz or less, or 10 GHz or less.

[0025] The antenna 21 outputs a high-frequency signal generated by an oscillator 41. The antenna 21 usually transmits the high-frequency signal without modulation. The antenna 21 may, for example, be directional, or may not be directional. In the former case, an object can be detected in a direction in which the radiation intensity of the electromagnetic field is high according to the directivity. When an omnidirectional antenna 21 is used, an object in the vicinity of the antenna 21 can be detected regardless of the direction.

[0026] The variable output unit 42 outputs according to the power of the high frequency signal that changes according to the change in the characteristics of the antenna 21. The change in the characteristics of the antenna 21 may be a change in the impedance of the antenna 21. In general, the impedance of the antenna 21 is often designed and manufactured to be 50Ω or 75Ω. However, if an object that was not assumed in the design stage of the antenna 21 is present in the vicinity of the antenna 21, the impedance of the antenna 21 changes. If the impedance of the antenna 21 changes, for example, the power of the high frequency signal input from the oscillator 41 to the antenna 21 changes, or the power of the high frequency signal reflected at the antenna end changes due to a mismatch of the antenna 21. Therefore, the variable output unit 42 outputs according to the power of the high frequency signal from the oscillator 41, which changes according to the change in the impedance of the antenna 21, or the power of the high frequency signal reflected at the antenna 21. By observing the change in the variable output unit 42, it is possible to determine whether an object has approached the antenna 21. In this case, the object is detected according to the change in the transmission signal of the antenna 21.

[0027] There are various possible specific configurations for the variable output section 42 which performs output according to the power of the high frequency signal which changes in response to changes in the characteristics of the antenna 21, and some of these configurations will be described below.

[0028] As shown in FIG. 3A, the change output unit 42 may have a directional coupler 44 and a detector 45. The directional coupler 44 is inserted in a transmission path between the oscillator 41 and the antenna 21, and branches a part of the high-frequency signal flowing from the oscillator 41 toward the antenna 21. The branched high-frequency signal is input to the detector 45. The directional coupler 44 may be a unidirectional coupler that branches only a part of the high-frequency signal flowing from the oscillator 41 toward the antenna 21. It is preferable that the directional coupler 44 has a low insertion loss and transmits most of the high-frequency signal from the oscillator 41 to the antenna 21. Therefore, most of the high-frequency signal from the oscillator 41 is input to the antenna 21 and radiated into the air.

[0029] Detector 45 detects the high frequency signal branched by directional coupler 44, and outputs a detection voltage that is the detection result. This detection voltage corresponds to the power of the high frequency signal. Therefore, by observing the change in the detection voltage, it is possible to know the change in the power of the high frequency signal output from oscillator 41, and the signal output from antenna 21 can be monitored.

[0030] The object detection unit 43 detects an object according to a change in the output from the change output unit 42. In the proximity sensor 20 shown in Fig. 3A, the output from the change output unit 42 is the detection voltage output from the detector 45. Detecting an object according to a change in the output from the change output unit 42 may mean detecting an object when the output itself changes, or may mean detecting an object according to a change in specific information obtained according to the output.

[0031] For example, when the oscillator 41 oscillates only a high-frequency signal of a specific frequency, the object detection unit 43 may detect an object when the output from the change output unit 42 changes, and may not detect an object when the output does not change. Note that a change in the output may mean that the output has changed beyond a predetermined threshold. The threshold may be set to a value equivalent to the measurement error, for example.

[0032] Also, for example, when the oscillator 41 oscillates a high-frequency signal with a frequency within a predetermined range while changing the frequency, the object detection unit 43 may detect an object when the resonance frequency specified according to the output from the change output unit 42 changes, and may not detect an object when the resonance frequency does not change. Note that the change in the resonance frequency may be when the resonance frequency has changed beyond a predetermined threshold value. The threshold value may be set to a value equivalent to the measurement error, for example.

[0033] The frequency characteristic of the detection voltage is, for example, as shown in FIG. 6. For example, when the oscillator 41 is a sweep oscillator, in a situation where there is no object in the vicinity of the antenna 21, the relationship between the frequency and the detection voltage can be obtained as shown by the solid line in FIG. 6. In FIG. 6, the horizontal axis is the frequency, and the vertical axis is the detection voltage. When an object is present in the vicinity of the antenna 21, the impedance of the antenna 21 changes, and the voltage of the high-frequency signal changes accordingly, so that the frequency characteristic of the detection voltage becomes, for example, as shown by the dashed line in FIG. 6. Therefore, by detecting a change in the detection voltage at a predetermined frequency from the solid line to the dashed line, or by detecting a change from the resonant frequency of the solid line to the resonant frequency of the dashed line, it is possible to detect that an object is present in the vicinity of the antenna 21. In FIG. 6, the resonant frequency is shown as the frequency at which the detection voltage becomes minimum, but depending on the measurement method, the frequency at which the detection voltage becomes maximum may become the resonant frequency.

[0034] 6 shows a case where the waveform as a whole changes in the direction of decreasing frequency according to the proximity of an object to antenna 21, but this is only one example, and depending on various conditions, the waveform may change in the direction of increasing frequency, or the detected voltage may change not only in the frequency direction but also in the direction of increasing or decreasing the detected voltage. In any case, the proximity of an object to antenna 21 changes the transmission signal of antenna 21, and the frequency characteristics of the detected voltage change.

[0035] The object detection unit 43 can also specify the distance to the object to be detected according to the degree of change in the detection voltage at a predetermined frequency. The object detection unit 43 can also specify the distance to the object according to the degree of change in the resonant frequency. For example, in the vicinity of the antenna 21 (for example, within a distance of about half the wavelength), the relationship between the distance between the antenna 21 and the object and the detection voltage becomes linear. Therefore, this property may be utilized to measure the distance from the antenna 21 to the object to be detected.

[0036] Next, the operation of the proximity sensor 20 will be briefly described. When the oscillator 41 oscillates a high-frequency signal of a single frequency, the detector 45 outputs a detection voltage related to the high-frequency signal of that frequency. Therefore, the object detection unit 43 monitors the detection voltage. When a human body or other object approaches the antenna 21, the impedance of the antenna 21 changes, causing a change in the power of the high-frequency signal, and as a result, the detection voltage output from the detector 45 also changes. When the detection voltage changes in this way, the object detection unit 43 can detect an object in the vicinity of the antenna 21 by detecting the change.

[0037] Also, when the oscillator 41 oscillates a high-frequency signal in a predetermined frequency range while changing the frequency, the detector 45 outputs a detection voltage of the high-frequency signal according to the frequency range. Therefore, the object detection unit 43 receives a change in the detection voltage according to the frequency range. The object detection unit 43 may perform the same process as described above using only the detection voltage of a specific frequency, as in the case where the oscillator 41 oscillates a high-frequency signal of a single frequency. Alternatively, the object detection unit 43 may specify a resonance frequency at which the detection voltage becomes an extreme value, using the change in the detection voltage according to the received frequency range. When a human body or other object approaches the antenna 21, the impedance of the antenna 21 changes, causing the power of the high-frequency signal to change, and as a result, the resonance frequency also changes. In this way, when the resonance frequency changes, the object detection unit 43 can detect the change and detect an object in the vicinity of the antenna 21.

[0038] The output unit 30 performs an output in response to the detection of an object by the detection unit 22. For example, the output unit 30 may output that when an object is detected. By such an output, for example, an employee can be notified that a customer has come to the reception or the cash register, or that a customer has sat down at a table. Then, the employee can immediately attend to the customer. Note that, when the detection unit 22 detects the distance to the object to be detected, the output unit 30 may perform an output in response to the distance. For example, when the distance to the detected person is greater than a threshold value, the output unit 30 may output that a visitor has arrived but has not yet sat down. On the other hand, for example, when the distance to the detected person is less than the threshold value, the output unit 30 may output that a visitor has arrived and has already sat down.

[0039] Here, this output may be, for example, a display on a display device (e.g., a liquid crystal display or an organic EL display), a wired or wireless transmission via a communication line to a specified device, an audio output by a speaker, or a transfer to another component. The output unit 30 may or may not include a device that performs the output (e.g., a display device or a communication device). The output unit 30 may be realized by hardware, or may be realized by software such as a driver that drives those devices.

[0040] As described above, according to the droplet diffusion prevention device 1 of this embodiment, since an object can be detected by the proximity sensor 20, it is possible to detect, for example, a person approaching the planar member 10. Therefore, the droplet diffusion prevention device can also be used to detect people, etc. Also, by forming the antenna 21 from a transparent conductor, it is possible to prevent the antenna 21 from interfering with vision.

[0041] Next, modified examples of the proximity sensor 20 according to the present embodiment will be described. First, modified examples of the change output unit 42 will be described. In addition, in the modified examples 1 and 2, similar to the proximity sensor 20 of FIG. 3A, an output is generated according to the power of the high frequency signal input from the oscillator 41 to the antenna 21. On the other hand, in the modified example 3, unlike the proximity sensor 20 of FIG. 3A, an output is generated according to the power of the high frequency signal reflected at the antenna end. In either case, the detection unit 22 detects an object according to the change in the transmission signal of the antenna 21.

[0042] [Variation 1 of the change output section] In the proximity sensor 20 shown in Fig. 3A, when radio waves of a frequency different from the high frequency signal generated by the oscillator 41 enter from the antenna 21, a certain degree of isolation can be achieved by the isolation of the directional coupler 44, but there is a possibility that the resulting change can be observed by the detector 45. Such a problem can be solved by the configuration of the change output section 42 shown in Fig. 3B. The configuration of the proximity sensor 20 shown in Fig. 3B other than the change output section 42 is the same as described above, and detailed description thereof will be omitted.

[0043] The variation output section 42 shown in FIG. 3B includes a directional coupler 44, a distributor 46, a mixer 47, and a low-pass filter 48. The distributor 46 distributes the high frequency signal flowing from the oscillator 41 toward the antenna 21 into a first high frequency signal and a second high frequency signal. The first high frequency signal is output to the directional coupler 44, and the second high frequency signal is output to the mixer 47.

[0044] 3A, except that the directional coupler 44 branches a part of the first high frequency signal flowing from the distributor 46 toward the antenna 21 and outputs the branched signal to the mixer 47. As explained above, most of the first high frequency signal is radiated from the antenna 21.

[0045] The mixer 47 is a mixer that mixes the second high-frequency signal from the distributor 46 and the high-frequency signal branched by the directional coupler 44. In the mixer 47, the second high-frequency signal is multiplied by the high-frequency signal from the directional coupler 44. The signal resulting from this multiplication contains a component of the frequency sum of the two input signals and a component of the frequency difference between them.

[0046] Low-pass filter 48 extracts the DC component from the output signal of mixer 47. Therefore, the frequency sum component output from mixer 47 is removed by low-pass filter 48, and only the frequency difference component is output.

[0047] Here, the two signals input to the mixer 47 are both generated by the oscillator 41 and have the same frequency. Therefore, the frequency difference component becomes DC. The output of the detector 45 in the proximity sensor 20 shown in FIG. 3A corresponds to this DC. If a signal of a different frequency from the high-frequency signal generated by the oscillator 41 is mixed in from the antenna 21, the mixer 47 will generate a sum component and a difference component with the frequency of the high-frequency signal generated by the oscillator 41. Since neither of these signals becomes DC, they are not blocked by the low-pass filter 48 and output.

[0048] [Variation 2 of the change output unit] In the proximity sensor 20 shown in Fig. 3A, the change in the power of the high frequency signal is detected using the detection voltage. On the other hand, since what is to be measured is the power of the high frequency signal output from the oscillator 41, the power may be measured directly in the transmission path of the high frequency signal from the oscillator 41 to the antenna 21. Therefore, the change output unit 42 may directly measure the power of the high frequency signal using the current and the voltage. The change output unit 42 that measures the power of the high frequency signal may have, for example, a clamp meter that measures the current of the high frequency signal input to the antenna 21, a voltmeter that measures the voltage of the high frequency signal input to the antenna 21, and a calculation unit that calculates the power of the high frequency signal using the measurement results of the clamp meter and the voltmeter.

[0049] By using such a change output unit 42, an object in the vicinity of antenna 21 can be detected in object detection unit 43 in the same manner as described above, using the power output from change output unit 42. Since clamp meters and voltmeters can usually only measure low-frequency radio-frequency signals, proximity sensors 20 having change output unit 42 configured in this way are limited to those that use radio-frequency signals in a lower frequency band.

[0050] [Variation 3 of the change output section] 3A, a part of the high frequency signal flowing from the oscillator 41 toward the antenna 21 is branched to the detector 45 by the directional coupler 44, but the directional coupler 44 may also branch a part of the reflected signal returning from the antenna 21 to the oscillator 41 and output it to the detector 45. In this way, the reflected signal from the output side can be monitored. As such a directional coupler 44, for example, a bidirectional coupler may be used.

[0051] When an object is present near the antenna 21, the reflection coefficient of the antenna 21 changes compared to when the object is not present. In addition, a signal output from the antenna 21 that is reflected by the object also returns to the antenna 21. By detecting these signals with the detector 45, it becomes possible to detect an object in a non-contact manner, similar to the proximity sensor 20 shown in Fig. 3A.

[0052] In the configuration of Fig. 3A, if the directional coupler 44 is changed so as to monitor the reflection from the antenna 21, it becomes more susceptible to the influence of other signals input to the antenna 21. In order to reduce such influence, the proximity sensor 20 shown in Fig. 3B may use a directional coupler 44 that branches a part of the reflected signal returning from the antenna 21 to the oscillator 41 and outputs it to the mixer 47. In this case, as explained above, it is possible to deal with a situation in which an unintended radio wave is input to the antenna 21.

[0053] Furthermore, although several variations in the configuration of the change output section 42 have been described, it goes without saying that the change output section 42 may output in response to a change in the characteristics of the antenna 21 using a configuration other than those described above.

[0054] [Object detection using multiple antennas] In the present embodiment, the case where one antenna 21 is used has been mainly described, but this is not essential. Two or more antennas 21 may be provided on the planar member 10, and the detection unit 22 may detect an object for each of the two or more antennas 21. By detecting an object in this manner, it is possible to detect the object over a wider range, and also to specify the position of the object in more detail.

[0055] FIG. 4 is a schematic diagram showing an example of a droplet diffusion prevention device 1 including a planar member 10 provided with a plurality of antennas 21a to 21d. By performing object detection processing for each of the four antennas 21a to 21d, it is possible to detect objects at each position where the antennas 21a to 21d are provided. For this reason, the detection unit 22 may have a variable output unit 42 and an object detection unit 43 for each of the antennas 21a to 21d. Note that the high-frequency signal may be a signal oscillated by a single oscillator 41, which may be distributed and used. Also, the output unit 30 may change the content of the output depending on the antenna 21 where the object is detected. For example, assume that chairs are placed in front of the antennas 21a and 21c, and chairs are also placed in front of the antennas 21b and 21d. When an object is detected by all of the antennas 21a to 21d, the output unit 30 may output that two adults have arrived, and when an object is detected by the antennas 21a, 21c, and 21d, the output unit 30 may output that one adult and one child have arrived. In this way, by using the multiple antennas 21a to 21d, it is possible to grasp the number of visitors and distinguish between adults and children.

[0056] Furthermore, even when multiple antennas 21 are used, detection may also be performed including the distance from each antenna 21. In this case, by using multiple antennas 21, it is also possible to detect a three-dimensional object. Furthermore, the number of antennas 21 may be other than four. For example, two, three, five or more antennas 21 may be provided on the planar member 10.

[0057] [Detection of objects on both sides of a planar component] When a planar patch antenna is used as the antenna 21, radio waves are usually only output from the antenna surface side, and no radio waves are output from the ground surface side, so that an object on the ground surface side cannot be detected. On the other hand, the patch antenna as the first antenna 21 is arranged on the planar member 10 so that the antenna surface is on the first surface side of the planar member 10, and the patch antenna as the second antenna 21 is arranged on the planar member 10 so that the antenna surface is on the second surface side of the planar member 10, so that the proximity sensor 20 can detect objects on both surfaces of the planar member 10. It is assumed that the second surface of the planar member 10 is the surface opposite to the first surface. In this case, the detection unit 22 may also perform object detection processing for each of the two antennas 21.

[0058] In the above case, the two antennas 21 need to be arranged at different positions, but a patch antenna capable of detecting objects on both sides may be used as the antenna 21. FIG. 5 is a diagram showing an example of such an antenna 21. In FIG. 5, the antenna 21 has a ground plane 51, a dielectric 52 provided on a first surface of the ground plane 51, an antenna surface 53 provided on the surface of the dielectric 52 opposite to the ground plane 51, a dielectric 54 provided on a second surface of the ground plane 51, and an antenna surface 55 provided on the surface of the dielectric 54 opposite to the ground plane 51. This antenna 21 has a configuration similar to two patch antennas with their ground plane sides bonded together. Therefore, objects can be detected on both the antenna surface 53 side and the antenna surface 55 side. Although omitted in FIG. 5, the antenna surfaces 53 and 55 may be fed with power using a microstrip. Also in this case, the object detection process by the detection unit 22 may be performed for each of the patch antenna composed of the ground plane 51, the dielectric 52, and the antenna plane 53, and the patch antenna composed of the ground plane 51, the dielectric 54, and the antenna plane 55.

[0059] In this way, when the proximity sensor 20 detects an object on both sides of the planar member 10, the output unit 30 may output according to the side on which the object is detected. For example, when the first side of the planar member 10 is the side facing employees and the second side is the side facing visitors such as customers, when an object is not detected on the first side but is detected on the second side, the output unit 30 may output to call an employee. This output may be, for example, a voice output to call an employee or transmission of information for calling to a terminal held by the employee. In addition, when an object is detected on both the first side and the second side, or when an object is detected on the first side but not on the second side, the output unit 30 may not output to call an employee. In this way, by performing detection on both sides, more detailed output can be performed, and for example, it is possible to avoid calling an employee even when the employee is in front of a visitor.

[0060] [Modification of oscillator] In this embodiment, the case where a dedicated oscillator 41 that generates a high-frequency signal is used has been mainly described, but the oscillator 41 may be a communication device that performs general wireless communication. The high-frequency signal generated by the communication device may also be used for object detection. In this case, the high-frequency signal may be a modulated wave.

[0061] [Other variations] In addition, in the present embodiment, the case where the detection section 22 and the output section 30 are included in the detection unit 3 has been described, but this is not necessarily the case. The detection section 22 and the output section 30 may be attached to different units. In this manner, each process or function in the present embodiment may be provided in a single unit or device, or may be distributed across multiple units or devices.

[0062] In addition, although the case where the droplet diffusion prevention device 1 according to the present embodiment includes the output unit 30 has been described, this is not necessarily the case. The droplet diffusion prevention device 1 does not necessarily have to include the output unit 30. In this case, for example, the output of the detection unit 22 may be provided to an external device, and the output may be processed in the same manner as by the output unit 30 in the external device.

[0063] In addition, in the detection of a nearby object by the detection unit 22, other than the method using the change in impedance of the antenna 21, a method of receiving a reflected signal from an object and detecting the object from the change in its intensity or the difference in phase or frequency with the transmitted signal may be applied. In this case, the object is detected according to the change in the received signal of the antenna 21. When detecting an object according to the change in the received signal of the antenna 21, the configuration of Figs. 3A and 3B may be modified so that the directional coupler 44 branches a part of the signal from the antenna 21 to the detector 45 side. Also, with the configuration of the above-mentioned modified example 3, it is possible to detect an object according to the change in the received signal of the antenna 21. In this way, when detecting an object according to the change in the received signal of the antenna 21, it is possible to detect an object farther away from the antenna 21, for example, an object located at a position about several wavelengths away from the antenna 21. Furthermore, it is also possible to detect an object according to the change in both the transmitted signal and the received signal of the antenna 21. In this case, for example, a part of the high frequency signal flowing from the oscillator 41 to the antenna 21 may be branched using a first directional coupler and input to the first detector, and a part of the signal from the antenna 21 may be branched using a second directional coupler and input to the second detector, and the object may be detected by observing the degree of the received signal reflected against the transmitted signal using the outputs of the first and second detectors. In this case, since the change in the transmitted signal, i.e., the change in the output of the first detector, is smaller than the change in the output of the second detector, the object can be detected substantially using only the second detector. That is, the object can be detected by the configuration of the above-mentioned modified example 3. In this way, the detection unit 22 may detect the object according to the change in at least one of the transmitted signal and the received signal of the antenna 21.

[0064] In addition, in the present embodiment, the antenna 21 is used both as an antenna for transmission and reception, but it goes without saying that the antenna for transmission and the antenna for reception may be provided separately.

[0065] Furthermore, the present invention is not limited to the above-described embodiment, and various modifications are possible, and it goes without saying that these modifications are also included within the scope of the present invention. [Industrial Applicability]

[0066] As described above, according to one aspect of the droplet diffusion prevention device of the present invention, the effect is that the device for preventing droplet diffusion can also be used to detect objects, and is useful, for example, as a droplet diffusion prevention device that can detect visitors, etc. [Explanation of symbols]

[0067] 1 Droplet diffusion prevention device 10 Planar members 20 Proximity Sensor 21, 21a-21d Antenna 22 Detection unit 30 Output section

Claims

1. A transparent sheet-like member for preventing the spread of droplets; A droplet diffusion prevention device comprising an antenna provided on the planar member, and a proximity sensor having a detection unit that detects an object in response to changes in at least one of the transmitted signal and received signal of the antenna.

2. the proximity sensor has two or more antennas provided on the planar member, The droplet diffusion prevention device according to claim 1 , wherein the detection unit detects an object for each of the two or more antennas.

3. The droplet diffusion prevention device according to claim 1 or 2, wherein the detection unit also detects a distance to a detection target object.

4. The droplet diffusion prevention device according to claim 1 , wherein the antenna is made of a transparent conductor.

5. The droplet diffusion prevention device according to claim 1 , further comprising an output section that outputs in response to detection of an object by the detection section.

6. The droplet diffusion prevention device according to claim 1 , wherein the proximity sensor detects objects on both surfaces of the planar member.

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