JP2022122561A - Droplet detector - Google Patents

Abstract

To provide a droplet detector that can simply distinguish between droplets coming out from a person and dust in the air.SOLUTION: A droplet detector comprises: a channel that has an inflow port through which air flows in and an outflow port through which air flows out; a cell that is arranged on the channel; a light source that irradiates the air in the cell with light at a wavelength of 500 nm or less; a detection unit that acquires the intensity of light at a wavelength longer than 500 nm from light emitted from the air in the cell; and an output unit that, based on the acquired intensity, outputs a signal related to the concentration of droplets included in the air.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to droplet detection devices.

In Patent Document 1, fine particles floating in a space where people stay are collected, and when the amount of infectious substances contained in the collected fine particles exceeds a predetermined amount, it is suspected that the infectious substances have been discharged. A technique for identifying a suspected discharger and displaying information on the suspected discharger is disclosed.

JP 2019-83395 A

The technique disclosed in Patent Literature 1 uses fluorescence spectrometry or surface-enhanced Raman spectrometry using laser light to detect infectious substances. Therefore, there has been a problem that it is not possible to easily distinguish droplets (saliva, mucus, etc.) emitted from a person and dust in the air (dust, dust, etc.).

The present disclosure has been made in view of the above situation. That is, an object of the present disclosure is to provide a droplet detection device that can easily distinguish between droplets emitted from a person and dust in the air.

A droplet detection device according to the present disclosure includes a channel having an inlet for inflow of air and an outlet for outflow of air; A light source that emits light, a detection unit, and an output unit are provided. The detector acquires the intensity of light with a wavelength longer than 500 nm, among the light emitted from the air in the cell. The output unit outputs a signal related to the concentration of droplets contained in the air based on the intensity.

The droplet detection device may further include a light source filter that removes light with a wavelength longer than 500 nm on the optical path of the light emitted from the light source and between the light source and the cell.

The droplet detection device may further include a detection-side filter that removes light with a wavelength of 500 nm or less on the optical path of light emitted from the air in the cell and between the cell and the detection unit. .

The droplet detection device may further include a determination unit that determines whether or not a warning to the user is necessary based on the intensity. Further, the output unit may output an alarm as a signal when the determination unit determines that an alarm is necessary.

The determination unit may determine that an alarm is necessary when the intensity is equal to or greater than the first threshold.

The determination unit may determine that an alarm is necessary when the amount of change in intensity per unit time is equal to or greater than a second threshold.

The determination unit may determine that an alarm is necessary when the time average of the intensity during the predetermined period is equal to or greater than the third threshold.

The detection unit may acquire the intensity of light traveling in a direction substantially orthogonal to the direction of travel of the light emitted by the light source.

The channel may be curved in the section between the inlet and the cell or in the section between the cell and the outlet.

The droplet detection device may further include a collector provided in a section between the inlet and the cell on the flow path. The collecting part may collect floating matter having a size larger than a predetermined size contained in the air.

The collecting part may be a cyclone that collects suspended matter by centrifugal force generated by swirling air passing through the flow path.

The droplet detection device may further include a blower that generates a flow of air from the inlet to the outlet via the cells.

The inner surface of the cell may be covered with a non-fluorescent material that does not or hardly emits light with a wavelength longer than 500 nm.

The droplet detection device may further include a notification unit that receives a signal from the output unit and notifies the user based on the signal.

According to the present disclosure, it is possible to easily distinguish between droplets emitted from a person and dust in the air.

1 is a schematic diagram showing the configuration of a droplet detection device according to an embodiment; FIG. It is a flow chart which shows a processing procedure of a droplet detection device. It is a schematic diagram which shows the structure of the droplet detection apparatus which concerns on the modified example of one Embodiment.

Several exemplary embodiments are described below with reference to the drawings. In addition, the same code|symbol is attached|subjected to the part which is common in each figure, and the overlapping description is abbreviate|omitted.

[Configuration of droplet detection device]
FIG. 1 is a schematic diagram showing the configuration of a droplet detection device according to an embodiment of the present disclosure. As shown in FIG. 1 , the droplet detection device 1 includes a channel, a cell CL, a light source 21 , a detection section 23 , an output section 25 , a determination section 27 and a notification section 29 . The channel has an inlet 11 and an outlet 13 . In FIG. 1, black arrows indicate the flow of air in the flow path. A blower 15 may be provided on the flow path, and the blower 15 may generate a flow of air from the inlet 11 toward the outlet 13 . The notification unit 29 may be an external device provided outside the droplet detection device 1 .

Most of the flow path, the cell CL, the light source 21, and the detection unit 23 are housed in the housing HG, and the inlet 11 and the outlet 13 are open to the outside of the housing HG. ing. Air flows into the inflow port 11 from the outside of the housing HG, and air flows out of the outflow port 13 toward the outside of the housing HG. The housing HG is composed of a member that does not transmit light outside the housing HG. In addition, the inner wall of the housing HG may be painted black so as not to reflect light. Also, the inner wall of the housing HG may be non-fluorescent. The inner wall of the housing HG may be covered with a non-fluorescent material that does not or hardly emits light with a wavelength longer than 500 nm.

A cell CL is provided on the channel. The air that has flowed into the cell CL from the inlet 11 is introduced into the cell CL, and the air that has passed through the cell CL flows out from the outlet 13 . The inner surface of the cell CL (the surface in contact with the air flowing in from the inlet 11) is covered with a non-fluorescent substance that does not or hardly emits light with a wavelength longer than 500 nm. good too.

In addition, as shown in FIG. 1, the channel may be curved in the section between the inlet 11 and the cell CL. Also, the channel may be curved in the section between the cell CL and the outlet 13 . By bending the channel in these sections, the light entering the channel from the inlet 11 or the outlet 13 is suppressed from reaching the cell CL. Furthermore, the light entering the channel from the inlet 11 or the outlet 13 is suppressed from entering the detector 23 .

The light source 21 mainly irradiates the air passing through the cell CL with light having a wavelength of 500 nm or less. Irradiation light R1 emitted by the light source 21 travels toward the region TG located in the center of the cell CL. The light source 21 may be an LED, an ultraviolet lamp, or the like. Examples of the light source 21 are not limited to these.

A light source side filter F1 for removing light with a wavelength longer than 500 nm may be provided between the light source 21 and the cell CL on the optical path of the irradiation light R1 emitted from the light source 21 . This suppresses light with a wavelength longer than 500 nm in the irradiation light R1 from traveling toward the region TG. The light source side filter F1 may be a spectroscope such as a diffraction grating or a prism.

As shown in FIG. 1, a lens L1 and a window plate W1 that transmit the irradiation light R1 may be provided on the optical path of the irradiation light R1 emitted from the light source 21 . The irradiation light R1 may be condensed by a lens L1 and introduced into the cell CL. Alternatively, the irradiation light R1 may be condensed by a reflector (not shown) and introduced into the cell CL. As a result, the inside of the cell CL can be efficiently irradiated with light without irradiating light onto areas other than the cell CL.

The lens L1 and the window plate W1 may be made of inorganic glass such as quartz, organic glass such as polymethyl methacrylate resin, or the like. Examples of the lens L1 and the window plate W1 are not limited to these as long as they transmit the irradiation light R1.

The detection unit 23 mainly acquires the intensity of light with a wavelength longer than 500 nm, among the light emitted from the air passing through the cell CL. In FIG. 1, the incident light R2 entering the detection unit 23 is shown as being emitted from the region TG located in the center of the cell CL. In addition, the irradiation light R1 and the incident light R2 may be substantially perpendicular to each other instead of being parallel. For example, the detection unit 23 is a photodiode, a photomultiplier tube, or the like.

A detection-side filter F2 that removes light with a wavelength of 500 nm or less may be provided on the optical path of the incident light R2 emitted from the air in the cell CL and between the cell CL and the detection unit 23. . This suppresses light with a wavelength of 500 nm or less from entering the detector 23 . The detection-side filter F2 may be a spectroscope such as a diffraction grating or a prism.

As shown in FIG. 1, a lens L2 and a window plate W2 for transmitting the incident light R2 may be provided on the optical path of the incident light R2 emitted from the air in the cell CL. The incident light R<b>2 may be condensed by the lens L<b>2 and introduced into the detector 23 . In addition, the incident light R2 may be condensed by a concave mirror (not shown) and introduced into the detection section 23 . Further, when the incident light R2 is introduced into the detection unit 23, a slit or an iris diaphragm may be used to adjust the light amount of the incident light R2 and block stray light other than the incident light R2.

The lens L2 and the window plate W2 may be made of inorganic glass such as quartz, organic glass such as polymethyl methacrylate resin, or the like. Examples of the lens L2 and the window plate W2 are not limited to these as long as they transmit the incident light R2.

The light whose intensity is to be acquired by the detection unit 23 includes fluorescence or phosphorescence emitted by suspended matter contained in the air passing through the cell CL upon receiving the irradiation light R1 emitted by the light source 21. . The intensity of fluorescence or phosphorescence is roughly proportional to the concentration of the suspension. Therefore, by obtaining the light intensity by the detection unit 23, the concentration of suspended matter contained in the air passing through the cell CL can be estimated. Units for the estimated concentration include, for example, the number of suspended solids per unit volume, the weight of suspended solids per unit volume, and the like.

In addition, among the floating substances contained in the air, droplets emitted from humans contain substances of biological origin. As such, droplets from humans are more likely to emit fluorescent or phosphorescent light at wavelengths longer than 500 nm. On the other hand, non-biological substances among airborne substances have a low tendency to emit fluorescence or phosphorescence of light having a wavelength longer than 500 nm. Therefore, based on the intensity of light with a wavelength longer than 500 nm, it is possible to estimate the concentration of droplets from a person floating in the air.

Based on the light intensity acquired by the detection unit 23, the output unit 25 outputs a signal related to the concentration of droplets contained in the air passing through the cell CL (a signal indicating the concentration of droplets, a warning to the user regarding droplets, etc.). ). The signal output by the output unit 25 may be either an analog signal or a digital signal. The output unit 25 may output a signal related to the density of droplets to the notification unit 29, which will be described later.

The signal output by the output unit 25 may be transmitted to an external device (not shown). For example, a signal related to the concentration of droplets may be sent to the ventilation fan, and the ventilation fan may be controlled such that the higher the concentration of droplets, the greater the amount of ventilation by the ventilation fan. Alternatively, a signal related to the concentration of droplets may be sent to the air purifier, and the air purifier may be controlled to increase the output of the air purifier as the concentration of droplets increases.

Based on the light intensity acquired by the detection unit 23, the determination unit 27 determines whether or not a warning to the user is necessary. Note that the output unit 25 may output an alarm as a signal when the determination unit 27 determines that an alarm is necessary.

For example, the determination unit 27 may determine that an alarm is necessary when the light intensity obtained by the detection unit 23 is equal to or greater than the first threshold. Here, the first threshold is determined based on the concentration of droplets in the air at which an alarm needs to be issued. It can be said that the higher the intensity obtained by the detection unit, the higher the concentration of the biological substances floating in the air. Therefore, the intensity of the light emitted from the air containing the suspended matter with the lowest concentration among the concentrations of droplets in the air at which an alarm needs to be issued is predetermined as the first threshold.

Note that the determination unit 27 may use a value obtained by subtracting a predetermined gain from the light intensity acquired by the detection unit 23 as the intensity used for determination. Here, the predetermined gain is determined based on the background noise before starting the measurement when the droplet detection device 1 is placed in the environment to be measured. For example, the droplet detection device 1 is placed in an environment where people can be crowded, such as a conference room, a banquet hall, and a restaurant, and the intensity of light acquired by the detection unit 23 in a state where there is no crowd is defined as a predetermined gain. good too. As a result, erroneous determination due to background noise can be suppressed.

Further, the determination unit 27 may determine that an alarm is necessary when the amount of change in the light intensity per unit time obtained by the detection unit 23 is equal to or greater than the second threshold.

More specifically, the determination unit 27 stores the intensity of light acquired by the detection unit 23 for a predetermined time in the past, and calculates the amount of change in the latest acquired intensity from the past intensity. The determination unit 27 calculates the amount of change per unit time by dividing the amount of change by the predetermined time. Then, the determination unit 27 may determine whether or not the amount of change per unit time is equal to or greater than the second threshold. Thereby, it can be determined that it is necessary to issue an alarm to the user when the number of droplets in the air increases rapidly.

Furthermore, the determination unit 27 may determine that an alarm is necessary when the time average of the intensity of light acquired by the detection unit 23 during a predetermined period is equal to or greater than the third threshold.

More specifically, the determination unit 27 stores a plurality of light intensities acquired during a predetermined period in the past, and calculates the average of the plurality of light intensities. Then, the determination unit 27 may determine whether or not the average is equal to or greater than the third threshold. As a result, even when the strength measurement error is bad or when the concentration of droplets in the air fluctuates, it is possible to suppress erroneous determinations when it is determined that it is necessary to issue a warning to the user.

The notification unit 29 receives a signal related to the concentration of droplets from the output unit 25 and notifies the user based on the signal.

For example, when a signal indicating the concentration of droplets is received as the signal related to the concentration of droplets, the notification unit 29 may light more brightly as the concentration of droplets increases. Further, the notification unit 29 may blink at a higher frequency as the density of droplets increases. Furthermore, the notification unit 29 may display the density of the droplets on a screen (not shown) using numbers or a graph.

When receiving a warning to the user regarding droplets as a signal related to droplet density, the notification unit 29 may light up or blink to notify the warning.

The notification unit 29 is not limited to presenting various types of information as visual information. The notification unit 29 may present information to the user in the form of auditory information using a buzzer or a speaker, or generate vibration to present information to the user by stimulus caused by the vibration. may Also, the notification unit 29 may be an external device provided outside the droplet detection device 1 . For example, the notification unit 29 may be a device that displays an image, such as a display or a smart phone. The notification unit 29 may display an image, moving image, or the like to alert the user. The notification unit 29 may display a signal related to droplet density. Examples of the notification unit 29 are not limited to these.

[Configuration of droplet detection device according to modification]
FIG. 3 is a schematic diagram showing the configuration of a droplet detection device according to a modification of the embodiment of the present disclosure. As compared with the droplet detection device 1 shown in FIG. 1, the droplet detection device 1A shown in FIG.

The collection part 31 is provided in a section between the inlet 11 and the cell CL on the channel. The collecting unit 31 collects floating matter larger than a predetermined size contained in the air. For example, the collection unit 31 may be a particle sizer. The collecting unit 31 may be a filter having pores of a predetermined size, or may be a cyclone that collects suspended matter by centrifugal force generated by swirling air passing through the flow path. good. Floating matter having a size equal to or smaller than the predetermined size flows into the cell CL without being collected by the collection unit 31 .

The collection box 33 is a container into which the floating matter collected by the collection unit 31 flows. In particular, when the collecting unit 31 is a cyclone, suspended matter having a size larger than a predetermined size is discharged outside the collecting unit 31 without accumulating in the collecting unit 31 . Collect the collected floating matter. The collection box 33 may be exchanged each time a predetermined operating time of the droplet detection device 1A elapses.

[Processing procedure of droplet detection device]
Next, the processing procedure of the droplet detection device according to the present disclosure will be described with reference to the flowchart of FIG. The processing of the flowchart of FIG. 2 is started when the user operates the droplet detection device 1, 1A.

In step S<b>101 , the blower 15 is activated to generate a flow of air from the inlet 11 toward the outlet 13 .

In step S103, the detection unit 23 acquires the intensity of the light emitted from the air passing through the cell CL immediately after the droplet detection device 1, 1A is operated as the initial intensity. The timing for acquiring the initial intensity is not limited to immediately after the droplet detection devices 1 and 1A are operated, and may be the timing instructed by the user.

In step S105, the determination unit 27 stores the acquired initial intensity as a predetermined gain.

In step S107, the detection unit 23 acquires the intensity of light emitted from the air passing through the cell CL.

In step S<b>109 , the output unit 25 generates a droplet concentration signal (a signal related to droplet concentration) based on the light intensity acquired by the detection unit 23 . Alternatively, the determination unit 27 may perform determination based on the light intensity acquired by the detection unit 23 .

In step S111, the output unit 25 outputs a droplet concentration signal.

At step S113, it is determined whether or not to end the measurement based on the user's instruction. If the measurement is not finished (NO in step S113), the process returns to step S107. If the measurement is finished (YES in step S113), the process shown in the flowchart of FIG. 3 is finished.

[Effects of Embodiment]
As described in detail above, the droplet detection device according to the present disclosure includes a channel having an inlet for inflow of air and an outlet for outflow of air, cells positioned on the channel, and air in the cells. A light source for emitting light having a wavelength of 500 nm or less, a detection section, and an output section are provided. The detector acquires the intensity of light with a wavelength longer than 500 nm, among the light emitted from the air in the cell. The output unit outputs a signal related to the concentration of droplets contained in the air based on the intensity.

This makes it possible to easily distinguish droplets from people and dust in the air. For example, droplets from humans contain substances of biological origin and are more likely to emit fluorescent or phosphorescent light at wavelengths longer than 500 nm. For example, riboflavin (vitamin B2), which is often used for living body detection, and skim milk, which is often used as a simulated bacterium, have fluorescence intensity peaks at wavelengths longer than 500 nm. Non-biological materials, on the other hand, have a reduced tendency to fluoresce or phosphoresce at wavelengths longer than 500 nm. Therefore, based on the intensity of light with a wavelength longer than 500 nm, it is possible to estimate the concentration of droplets from a person floating in the air.

The droplet detection device may further include a light source filter that removes light with a wavelength longer than 500 nm on the optical path of the light emitted from the light source and between the light source and the cell. As a result, it is possible to suppress the scattered light from the floating matter floating in the air from entering the detection unit. As a result, it is possible to suppress the deterioration of the error in estimating the concentration of the droplets in the air.

The droplet detection device may further include a detection-side filter that removes light with a wavelength of 500 nm or less on the optical path of light emitted from the air in the cell and between the cell and the detection unit. . As a result, it is possible to suppress light emitted from the light source or light scattered by floating matter floating in the air from entering the detection unit. As a result, it is possible to suppress the deterioration of the estimation error of the concentration of droplets emitted from a person.

The droplet detection device may further include a determination unit that determines whether or not a warning to the user is necessary based on the intensity. Further, the output unit may output an alarm as a signal when the determination unit determines that an alarm is necessary. It can be said that the higher the intensity obtained by the detection unit, the higher the concentration of the biological substances floating in the air. Therefore, based on the concentration of droplets in the air, it is possible to determine whether or not it is necessary to issue a warning to the user. Also, by outputting an alarm, it is possible to actually issue an alarm to the user.

The determination unit may determine that an alarm is necessary when the intensity is equal to or greater than the first threshold. Thereby, it can be determined that it is necessary to issue an alarm to the user when the concentration of droplets in the air reaches or exceeds a predetermined concentration. In addition, by actually issuing an alarm to the user, the user can refrain from talking, evacuate from the room in which the droplet detection device is installed, and ventilate the room. That is, it is possible to prompt the user's behavior so that the user's health can be protected.

The determination unit may determine that an alarm is necessary when the amount of change in intensity per unit time is equal to or greater than a second threshold. Accordingly, it can be determined that it is necessary to issue an alarm to the user when the change in the concentration of the droplets in the air exceeds a predetermined value. In addition, by actually issuing an alarm to the user, the user can refrain from talking, evacuate from the room in which the droplet detection device is installed, and ventilate the room. That is, it is possible to prompt the user's behavior so that the user's health can be protected.

The determination unit may determine that an alarm is necessary when the time average of the intensity during the predetermined period is equal to or greater than the third threshold. Accordingly, it is possible to determine whether or not it is necessary to issue a warning to the user based on the average concentration obtained by time-averaging the concentrations of droplets in the air over a predetermined period. In particular, even when the intensity measurement error is bad or when there is fluctuation in the concentration of droplets in the air, it is possible to suppress erroneous determinations when it is determined that it is necessary to issue a warning to the user.

The detection unit may acquire the intensity of light traveling in a direction substantially orthogonal to the direction of travel of the light emitted by the light source. As a result, it is possible to suppress light emitted from the light source or light scattered by floating matter floating in the air from entering the detection unit. As a result, it is possible to suppress the deterioration of the estimation error of the concentration of droplets emitted from a person.

In particular, Rayleigh scattering (scattering by particles with a size smaller than the wavelength of light) among the scattered light from floating objects floating in the air is the smallest in the direction substantially perpendicular to the traveling direction of the light emitted from the light source. . Therefore, it is possible to minimize the influence of light scattered by floating matter floating in the air.

Among light scattered by floating objects in the air, Mie scattering (scattered by particles with a size similar to the wavelength of the light) has a relatively large proportion of scattering in the traveling direction of the light irradiated by the light source. big. Therefore, by obtaining the intensity of light traveling in a direction different from the traveling direction of the light emitted from the light source, it is possible to suppress the influence of light scattered by floating objects floating in the air. In particular, by obtaining the intensity of light traveling in a direction substantially perpendicular to the traveling direction of light emitted from the light source, it is possible to suppress the influence of light scattered by floating objects floating in the air.

The channel may be curved in the section between the inlet and the cell or in the section between the cell and the outlet. As a result, it is possible to prevent light entering the channel from the inlet or the outlet from reaching the cell and entering the detector. As a result, it is possible to suppress the deterioration of the estimation error of the concentration of droplets emitted from a person.

The droplet detection device may further include a collector provided in a section between the inlet and the cell on the flow path. The collecting part may collect floating matter having a size larger than a predetermined size contained in the air. As a result, it is possible to estimate the concentration of droplets containing viruses that are highly likely to affect human health among suspended substances contained in the air.

In general, the sedimentation velocity of particles is proportional to the square of the particle size. For example, when the sedimentation velocity of spherical particles with a specific gravity of 1 is calculated in the air, the sedimentation velocity of particles with a diameter of about 5 μm in air is about 5 cm per minute, while the sedimentation velocity of particles with a diameter of about 1 μm is It is about 12 cm per hour. Therefore, small-sized floating matter tends to float in the air for a long time, and there is a high possibility that it will be inhaled by humans or attached to human mucous membranes.

Therefore, by removing floating matter having a size larger than a predetermined size, it is possible to estimate the concentration of droplets containing viruses that are likely to affect human health. As a result, it is possible to improve the accuracy of estimating the concentration of droplets that are likely to affect human health.

The collecting part may be a cyclone that collects suspended matter by centrifugal force generated by swirling air passing through the flow path. As a result, suspended matter that is unlikely to affect human health can be effectively removed from the air. In particular, in the case of collecting suspended matter by centrifugal force, compared to the case of collecting suspended matter with a fine-mesh filter, the suspended matter breaks up into smaller sizes during the collection process. It is suppressed to do. Furthermore, the collected suspended matter is suppressed from being released into the air again. Therefore, it is possible to improve the accuracy of estimating the concentration of droplets that are likely to affect human health.

The droplet detection device may further include a blower that generates a flow of air from the inlet to the outlet via the cells. As a result, the air around the droplet detection device can be effectively taken into the interior of the cell. As a result, it is possible to more effectively estimate the concentration of droplets emitted from a person floating in the air around the droplet detection device.

The inner surface of the cell may be covered with a non-fluorescent material that does not or hardly emits light with a wavelength longer than 500 nm. As a result, it is possible to prevent the light emitted from the inner surface of the cell from entering the detection section and the deterioration of the estimation error of the concentration of the droplets emitted from the person.

The droplet detection device may further include a notification unit that receives a signal from the output unit and notifies the user based on the signal. As a result, the user can refrain from talking, evacuate from the room in which the droplet detection device is installed, and ventilate the room. That is, it is possible to prompt the user's behavior so that the user's health can be protected.

Each function illustrated in the above embodiments may be implemented by one or more processing circuits. Processing circuitry includes programmed processors, electrical circuits, etc., as well as devices such as application specific integrated circuits (ASICs) or circuit components arranged to perform the described functions. etc. are also included.

According to the present disclosure, it is possible to easily distinguish between droplets emitted from people and dust in the air. ensure healthy lives and promote well-being for all.”

Although several embodiments have been described, modifications or variations of the embodiments are possible based on the above disclosure. All components of the above embodiments and all features recited in the claims may be extracted individually and combined as long as they are not inconsistent with each other.

1, 1A droplet detection device 11 inlet 13 outlet 15 blower 21 light source 23 detection unit 25 output unit 27 determination unit 29 notification unit 31 collection unit CL cell F1 light source filter F2 detection filter

Claims (14)

a flow path having an inlet for inflow of air and an outlet for outflow of the air;
a cell located on the channel;
a light source that irradiates the air in the cell with light having a wavelength of 500 nm or less;
a detector that acquires the intensity of light with a wavelength longer than 500 nm, from among the light emitted from the air in the cell;
an output unit that outputs a signal related to the concentration of droplets contained in the air based on the intensity;
A droplet detection device comprising: 2. The droplet detection device according to claim 1, further comprising a light source filter that removes light with a wavelength longer than 500 nm on the optical path of the light emitted from the light source and between the light source and the cell. 3. The method according to claim 1, further comprising a detection-side filter that removes light with a wavelength of 500 nm or less on the optical path of the light emitted from the air in the cell and between the cell and the detection unit. droplet detection device. Further comprising a determination unit that determines whether or not a warning to the user is necessary based on the intensity,
The droplet detection device according to any one of claims 1 to 3, wherein the output section outputs the warning as the signal when the determination section determines that the warning is necessary. The droplet detection device according to claim 4, wherein the determination unit determines that the warning is necessary when the intensity is equal to or greater than a first threshold. The droplet detection device according to claim 4 or 5, wherein the determination unit determines that the warning is necessary when the amount of change in intensity per unit time is equal to or greater than a second threshold. The droplet detection device according to any one of claims 4 to 6, wherein the determination unit determines that the warning is necessary when the time average of the intensity during the predetermined period is equal to or greater than a third threshold. The droplet detection device according to any one of claims 1 to 7, wherein the detection unit acquires the intensity of light traveling in a direction substantially orthogonal to the direction of travel of the light emitted by the light source. The droplet detection device according to any one of claims 1 to 8, wherein the flow path is bent in a section between the inlet and the cell or in a section between the cell and the outlet. . further comprising a collection unit provided in a section between the inlet and the cell on the flow channel;
The droplet detection device according to any one of claims 1 to 9, wherein the collecting section collects floating matter having a size larger than a predetermined size contained in the air. 11. The droplet detection device according to claim 10, wherein the collecting section is a cyclone that collects the floating matter by centrifugal force generated by swirling of the air passing through the flow path. The droplet detection device according to any one of claims 1 to 11, further comprising a blower that generates the flow of air from the inlet to the outlet via the cells. The droplet detection device according to any one of claims 1 to 12, wherein the inner surface of the cell is covered with a non-fluorescent substance that does not or hardly emits light with a wavelength longer than 500 nm. The droplet detection device according to any one of claims 1 to 13, further comprising a notification unit that receives the signal from the output unit and notifies the user based on the signal.

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