PARTICLE DETECTION DEVICE

A particle detection device detects a biological particle. The particle detection device includes a collection sheet, a collection unit, a heating unit, a fluorescence detection unit, and a movement mechanism. The collection unit introduces an airborne particle into the device so that the airborne particle is collected on the collection sheet. The heating unit heats the particle collected on the collection sheet so as to increase fluorescence emitted from the particle. The fluorescence detection unit detects the fluorescence emitted from the particle which is collected on the collection sheet. The movement mechanism moves the collection sheet. With the configuration as described above, the particle detection device with which a measurement time period and the cost of measurement can be reduced can be provided.

TECHNICAL FIELD

The present invention generally relates to a particle detection device, and particularly relates to a particle detection device that detects biological particles.

BACKGROUND ART

Regarding related-art particle detection devices, for example, a method of detecting airborne microorganisms is disclosed in Japanese Unexamined Patent Application Publication No. 2007-135476 (PTL 1). In this method, simple sampling of airborne microorganisms is performed in order to count the number of the microorganisms.

The method of detecting airborne microorganisms disclosed in PTL 1 includes the following steps: that is, a step in which microorganisms in the atmosphere are collected on an adhesive sheet; a step in which a microorganisms collection surface of the adhesive sheet is brought into contact with a culture medium surface so as to cause fissiparity of the microorganisms to occur, and a step in which the microorganisms having been reproduced by fissiparity are observed and counted through the adhesive sheet.

Furthermore, a measurement device for suspended particulate matter is disclosed in Japanese Unexamined Patent Application Publication No. 2002-357532. An object of the measurement device for suspended particulate matter is to simultaneously measure the densities of suspended particulate matter and pollen in the atmosphere (PTL 2).

The measurement device disclosed in PTL 2 includes the following components: that is, a suspended particulate matter collection unit that causes suspended particulate matter in a sample gas to be collected on filter paper; a suspended particulate matter detection unit that irradiates the suspended particulate matter on the filter paper with β-rays and detects the amount of transmitted β-ray so as to detect the suspended particulate matter; and a pollen detection unit that irradiates the pollen contained in the suspended particulate matter with ultraviolet rays and detects the intensity of generated fluorescence so as to detect the amount of the pollen.

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

Technical Problem

According to the method of detecting airborne microorganisms disclosed in PTL 1, for example, the number of colonies of the microorganisms is measured by collecting the airborne microorganisms on the adhesive sheet with an air sampler and culturing the collected microorganisms (for one to seven days). However, the detection method utilizing culturing of microorganisms as described above requires a very long time period for obtaining measurement results and increases the cost of the measurement.

Accordingly, an object of the present invention is to address the above-described problems, that is, to provide a particle detection device with which the measurement time period can be reduced and the cost of measurement can be reduced.

Solution to Problem

A particle detection device according to the present invention detects a biological particle. The particle detection device includes a sheet-shaped member, a collection unit, a heating unit, a fluorescence detection unit, and a movement mechanism. The collection unit introduces an airborne particle into the device so that the airborne particle is collected on the sheet-shaped member. The heating unit heats the particle collected on the sheet-shaped member so as to increase fluorescence emitted from the particle. The fluorescence detection unit detects the fluorescence emitted from the particle which is collected on the sheet-shaped member. The movement mechanism moves the sheet-shaped member.

With the particle detection device structured as described above, the sheet-shaped member having low heat capacity is used so that the airborne particle is collected. Thus, a time period for heating the particle performed by the heating unit can be reduced, and energy consumed by the heating unit can be reduced. Thus, the particle detection device with which a measurement time period and the cost of measurement can be reduced can be realized.

Furthermore, the sheet-shaped member preferably includes an adhesive surface. In this case, the collection unit blows the airborne particle having been introduced into the device to the sheet-shaped member so that the particle is collected on the adhesive surface. With the particle detection device structured as described above, the particle can be collected by a further simplified device structure.

Furthermore, the movement mechanism preferably moves the sheet-shaped member between a first position, at which the particle is collected on the sheet-shaped member by the collection unit, a second position, at which the particle is heated by the heating unit, and a third position, at which the fluorescence is detected by the fluorescence detection unit. With the particle detection device structured as described above, the sheet-shaped member can be freely moved between a particle collection step performed by the collection unit, a particle heating step performed by the heating unit, and a fluorescence detection step performed by the fluorescence detection unit.

Furthermore, the sheet-shaped member preferably continuously extends in a sheet shape through the first position, at which the particle is collected on the sheet-shaped member by the collection unit, the second position, at which the particle is heated by the heating unit, and the third position, at which the fluorescence is detected by the fluorescence detection unit. With the particle detection device structured as described above, a plurality of steps from among the particle collection step performed by the collection unit, the particle heating step performed by the heating unit, and the fluorescence detection step performed by the fluorescence detection unit can be performed in parallel with one another.

Furthermore, the heating unit preferably includes a light source that emits light toward the particle. With the particle detection device structured as described above, a time period to heat the particle can be further reduced by irradiating the particle with the light emitted from the light source.

Furthermore, the movement mechanism preferably includes a sheet supply unit that supplies the sheet-shaped member to the collection unit and a sheet reception unit that collects the sheet-shaped member from the fluorescence detection unit. With the particle detection device structured as described above, the sheet-shaped member is supplied from the sheet supply unit to the collection unit while the sheet-shaped member is collected from the fluorescence detection unit to the sheet reception unit. Thus, particle measurement can be continuously performed.

Furthermore, the particle detection device preferably further includes a housing that contains the sheet-shaped member wound into a roll and that is detachably attached to the device. With the particle detection device structured as described above, the particle measurement can be continuously performed by periodically replacing the housing.

Furthermore, the particle detection device preferably detects the biological particle from a difference between an amount of the fluorescence detected from the particle before the particle is heated by the heating unit and an amount of the fluorescence detected from the particle after the particle has been heated by the heating unit. With the particle detection device structured as described above, measurement errors ascribable to particles other than the biological particle can be reduced, and accordingly, the biological particle can be highly precisely detected.

Advantageous Effects of Invention

As has been described above, according to the present invention, the particle detection device with which the measurement time period and the cost of measurement can be reduced can be provided.

DESCRIPTION OF EMBODIMENTS

An embodiment of the present invention will be described with reference to the drawings. The same or corresponding elements are denoted by the same reference signs in the drawings referred to in the following description.

A particle detection device according to the present embodiment detects biological particles such as pollen, microorganisms, and molds. The principle of detecting biological particles using the particle detection device according to the present embodiment is initially described.

FIG. 1includes graphs illustrating a change in fluorescent intensity of biological particles before and after heating and a change in fluorescent intensity of dust before and after heating.

Airborne biological particles emit fluorescence when being irradiated with ultraviolet light or blue light. In air, however, other particles such as lint of chemical fiber (also referred to as dust hereafter), which emit fluorescence similarly to biological particles, are also suspended. Thus, only by detecting fluorescence, it is impossible to distinguish whether the fluorescence comes from biological particles or dust.

When, as illustrated inFIG. 1, biological particles and dust are heated and changes in the fluorescent intensities (amount of fluorescence) thereof are measured before and after heating, the fluorescent intensity emitted from the dust is not changed by heating and the fluorescent intensity emitted from the biological particles is increased by heating. The particle detection device according to the present embodiment measures the fluorescent intensity of mixed particles of biological particles and dust before and after heating, and obtains the difference between the fluorescent intensity before and after the heating, thereby determining the number of the biological particles.

FIG. 2is a graph illustrating the relationship between an increase ΔF in the fluorescent intensity before and after heating and the concentration of biological particles.

Referring toFIG. 2, an increase ΔF1in the fluorescent intensity is specifically calculated from the difference in the fluorescent intensity before and after heating. A concentration N1of biological particles corresponding to the calculated increase ΔF1is found in accordance with a prepared relationship between the increase ΔF in the fluorescent intensity and the concentration N of biological particles. The correspondence relationship between the increase ΔF and the concentration N of biological particles is experimentally predetermined.

Next, the structure of the particle detection device according to the present embodiment is described.FIG. 3is a side view of the particle detection device according to the embodiment of the present invention.

Referring toFIG. 3, a particle detection device10according to the present embodiment includes a collection sheet12, a collection unit21, a heating unit31, and a fluorescence detection unit41.

The collection unit21, the heating unit31, and the fluorescence detection unit41are spaced apart from one another. The collection unit21, the heating unit31, and the fluorescence detection unit41are linearly arranged. In this linear arrangement, the heating unit31is located between the collection unit21and the fluorescence detection unit41. The collection unit21is disposed adjacent to a sheet supply drum52, and the fluorescence detection unit41is disposed adjacent to a sheet reception drum53. The sheet supply drum52and the sheet reception drum53will be described later.

FIG. 4is an enlarged side view illustrating a region surrounded by a two-dot chain line IV inFIG. 3. Referring toFIGS. 3 and 4, the collection sheet12on which biological particles are collected uses a sheet-shaped member. In the present embodiment, mixed particles of biological particles and dust such as lint of chemical fiber are collected on the collection sheet12.

The collection sheet12is formed to have a sheet shape that has a specified width and extends in a single direction. The collection sheet12has a thin plate shape. The collection sheet12has a degree of flexibility so that the collection sheet12can be wound around the sheet supply drum52and the sheet reception drum53, which will be described later.

The collection sheet12has a sheet shape that continuously extends through the following positions: that is, a collection position81serving as a first position at which particles are collected on the collection sheet12by the collection unit21; a heating/cooling position82serving as a second position at which the heating unit31heats the particles; and a fluorescence detection position83serving as a third position at which the fluorescence detection unit41detects fluorescence emitted from the particles. The collection sheet12has a length greater than the distance between the collection position81and the fluorescence detection position83.

The collection sheet12has an adhesive surface12athat holds the collected particles. The adhesive surface12ahas adhesive properties. In the present embodiment, the adhesive surface12ahas a sheet shape continuously extends in the same single direction as that of the collection sheet12.

The collection sheet12includes a base material13and an adhesive14. The base material13has a sheet shape that has a specified width and extends in a single direction. The adhesive14is provided on one of the surfaces of the base material13. The adhesive surface12aof the collection sheet12that holds the collected particles is formed by the surface of the adhesive14.

With the structure as described above, the particles are attracted to the adhesive surface12a. Thus, the particles can be collected with a simple structure. Furthermore, the particles can be moved between the collection position81, the heating/cooling position82, and the fluorescence detection position83while being held by the adhesive surface12ain a further stable manner.

The base material13preferably uses a material that has a high thermal resistance and an appropriate strength. More specifically, the base material13preferably uses a resin material having a high thermal resistance, for example, polyimide. Alternatively, the base material13may use glass or one of a variety of metal sheets (for example, a copper sheet). When the base material13has a high thermal conductivity than that of the adhesive14, the thickness of the base material13is preferably greater than that of the adhesive14.

The adhesive14preferably uses an acrylic or silicone based adhesive.

The adhesive14may be arranged on the base material13in the pitch equal to or substantially equal to the pitch of the collection position81, the heating/cooling position82, and the fluorescence detection position83. In this case, the cost of the collection sheet12can be reduced and the particles can be prevented from being attracted to undesired portions of the collection sheet12.

FIG. 5is a side view illustrating the collection unit provided in the particle detection device illustrated inFIG. 3. Referring toFIG. 5, the collection unit21introduces airborne particles into the device so that the particles are collected on the collection sheet12.

The collection unit21includes a collection barrel22and a fan23. The fan23generates an air flow that causes the air to be taken into the device and to be blown toward the collection sheet12. The collection barrel22guides the air which has been taken into the device by driving the fan23to the collection sheet12.

The collection barrel22includes a suction portion22pand a discharge portion22q. The collection barrel22has a barrel shape. The collection barrel22has a barrel shape in which the suction portion22pand the discharge portion22qof the collection barrel22are open ends. The diameter of the collection barrel22is large in the suction portion22pand small in the discharge portion22q. The diameter of the collection barrel22decreases from the suction portion22ptoward the discharge portion22q. The collection barrel22is positioned so that the discharge portion22qfaces the adhesive surface12aof the collection sheet12. The fan23is disposed on a side of the collection sheet12opposite to the collection barrel22with the collection sheet12interposed therebetween.

During the collection step performed by the collection unit21, airborne particles90are sucked into the collection barrel22through the suction portion22pdue to driving of the fan23. The particles90include biological particles91and dust92(inorganic foreign matter) such as lint of chemical fiber. The speed at which the particles90are sucked into the collection barrel22increases as the particles90approach the tapered discharge portion22qfrom the suction portion22p, and the particles90are blown to the adhesive surface12aof the collection sheet12through the discharge portion22q. The particles90are held by the adhesive surface12ahaving adhesive properties, thereby being collected on the collection sheet12.

The particles90may be collected with an air sampler device that can be used for collection in a culturing method.

FIG. 6is a side view illustrating a variant of the collection unit illustrated inFIG. 5. Referring toFIG. 6, a collection barrel27is provided instead of the collection barrel22illustrated inFIG. 5, and an electrostatic stylus25serving as a discharge electrode and a high-voltage power source26serving as a power unit are provided in the present variant. The air that contains the particles is guided toward the collection sheet12, which is positioned so as to face the electrostatic stylus25, through the collection barrel27. The high-voltage power source26is provided as the power unit to generate a potential difference between the collection sheet12and the electrostatic stylus25.

In the present variant, the collection sheet12is formed of glass. An electrically conductive transparent film is formed on a surface of the glass.

The electrostatic stylus25extends from the high-voltage power source26, penetrates through a wall portion of the collection barrel27, and reaches the inside of the collection barrel27. The electrostatic stylus25faces the surface of the collection sheet12. In the present embodiment, the electrostatic stylus25is electrically connected to a positive electrode of the high-voltage power source26. The film provided on the collection sheet12is electrically connected to a negative electrode of the high-voltage power source26.

In the case where the electrostatic stylus25is electrically connected to the positive electrode of the high-voltage power source26, the film provided on the collection sheet12may be connected to a ground potential. Alternatively, the electrostatic stylus25may be electrically connected to the negative electrode of the high-voltage power source26and the film provided on the collection sheet12may be electrically connected to the positive electrode of the high-voltage power source26.

During the collection step performed by the collection unit21, the air outside the device is introduced to the collection sheet12through the collection barrel27due to driving of the fan23. In so doing, by generating the potential difference between the electrostatic stylus25and the collection sheet12by using the high-voltage power source26, the airborne particles are positively charged around the electrostatic stylus25. The positively charged particles are moved to the collection sheet12by electrostatic forces and attracted to the electrically conductive film, thereby being collected on the collection sheet12.

Thus, in the present variant, the particles are collected on the collection sheet12by electrostatic collection that utilizes the electrostatic forces. In this case, the particles can be reliably held on the collection sheet12during detection of the particles, and after the particles have been detected, the particles can be easily removed from the collection sheet12.

Furthermore, by using the needle-shaped electrostatic stylus25as the discharge electrode, the charged particles can be attracted to a very narrow region of the surface of the collection sheet12facing the electrostatic stylus25, the region corresponding to a region irradiated with a light emitting element. Thus, in the fluorescence detection step, which will be described later, microorganisms having been attracted can be efficiently detected.

FIG. 7is a side view illustrating the heating unit provided in the particle detection device illustrated inFIG. 3. Referring toFIG. 7, the heating unit31heats the particles collected on the collection sheet12by the collection unit21.

The heating unit31includes a lamp32and a condensing lens33. The lamp32is provided as a light source that emits light. The lamp32faces the adhesive surface12aof the collection sheet12. The lamp32uses a halogen lamp, a far-infrared radiation heater, a laser, a xenon lamp, or the like. The condensing lens33concentrates light emitted from the lamp32onto the adhesive surface12aof the collection sheet12. The condensing lens33is disposed between the lamp32and the collection sheet12.

The collection sheet12is preferably formed of a light absorbing member that can absorb the light emitted from the lamp32.

During the heating step performed by the heating unit31, the light emitted from the lamp32is concentrated on the adhesive surface12aof the collection sheet12through the condensing lens33. This causes the collection sheet12to be heated. The heat is transferred from the heated collection sheet12to the particles, thereby the particles collected on the collection sheet12are heated. In the present embodiment, by concentrating the light, the collection sheet12can be locally heated. This can further reduce a time period to heat the particles and reduce power consumption of the lamp32.

FIG. 8is a side view illustrating a first variant of the heating unit illustrated inFIG. 7. Referring toFIG. 8, the present variant further includes a light absorbing member36. The light absorbing member36is formed of a material that absorbs the light emitted from the lamp32at a high light absorption ratio. The light absorbing member36is provided so as to be in contact with a rear surface of the collection sheet12disposed on a rear side of the adhesive surface12a.

The collection sheet12is formed of a light-transmitting member that allows the light emitted from the lamp32to be transmitted therethrough.

In such a structure, the light absorbing member36absorbs the light emitted from the lamp32, and accordingly, is heated during the heating step performed by the heating unit31. The heat is transferred from the heated light absorbing member36and the heated collection sheet12to the particles collected on the collection sheet12, thereby the particles are heated.

FIG. 9is a side view illustrating a second variant of the heating unit illustrated inFIG. 7. Referring toFIG. 9, the present variant includes a ceramic heater37serving as a heat generating unit instead of the lamp32and the condensing lens33illustrated inFIG. 7. The ceramic heater37is provided so as to be in contact with the rear surface of the collection sheet12disposed on the rear side of the adhesive surface12a.

The collection sheet12preferably uses a metal material through which heat generated by the ceramic heater37is easily transferred (for example, copper) or a thin resin material (for example, polyimide) having a small thickness (equal to or less than 100 μm).

In such a structure, the collection sheet12is heated by the heat generated by the ceramic heater37during the heating step performed by the heating unit31. The heat is transferred from the heated collection sheet12to the particles, thereby the particles are heated.

FIG. 10is a perspective view illustrating the fluorescence detection unit provided in the particle detection device illustrated inFIG. 3. Referring toFIG. 10, the fluorescence detection unit41detects the fluorescence emitted from the particles which are collected on the collection sheet12. In the present embodiment, the fluorescence detection unit41detects the fluorescence emitted from the particles before and after heating performed by the heating unit31.

The fluorescence detection unit41includes a light emitting element43, a condensing lens42, a light receiving element44, and a Fresnel lens45. The light emitting element43and the condensing lens42are provided as parts of an excitation optical system that irradiates the adhesive surface12aof the collection sheet12with excitation light. The light receiving element44and the Fresnel lens45are provided as parts of a light receiving optical system that receives the fluorescence emitted from the particles90when the particles90are irradiated with excitation light from the excitation optical system.

The light emitting element43uses, for example, a semiconductor laser element that emits blue laser light at a wavelength of 405 nm. The light emitting element43may instead use an LED (light emitting diode). The wavelength of light emitted from the light emitting element43may be in an ultraviolet range or a visible range as long as the light can excite biological particles and cause the biological particles to emit the fluorescence. The light receiving element44uses, for example, a photodiode or an image sensor.

Excitation light EL emitted by the light emitting element43is concentrated while passing through the condensing lens42. An excitation light irradiation region46on the adhesive surface12aof the collection sheet12is irradiated with the excitation light EL having been thus condensed. The excitation light EL is obliquely incident upon the adhesive surface12aof the collection sheet12. InFIG. 10, a one-dot chain line denoted by sign OD1indicates a light beam direction of the excitation light EL. Here, the light beam direction refers to a direction in which light beam components of light (excitation light EL in this case) travel. The light beam direction OD1of the excitation light EL can also be referred to as an optical axis of the excitation optical system.

Light resulting from regular reflection of the excitation light EL at the adhesive surface12aof the collection sheet12forms reflected light RL. InFIG. 10, a one-dot chain line denoted by sign OD2indicates a light beam direction of the reflected light RL. Since the excitation light EL is obliquely incident upon the adhesive surface12aof the collection sheet12, the reflected light RL that undergoes regular reflection at the adhesive surface12ais also reflected obliquely relative to the adhesive surface12a.

The particles90are collected in the excitation light irradiation region46. The particles90include the biological particles91such as microorganisms and the dust92such as lint of chemical fiber. Arrows denoted by sign F inFIG. 10indicate fluorescence emitted from the particles90. The fluorescence F is omnidirectionally emitted from parts of surfaces of the particles90irradiated with the excitation light EL. The fluorescence F traveling toward the light receiving optical system is concentrated while passing through the Fresnel lens45and received by the light receiving element44. By using the Fresnel lens45as a condensing lens to concentrate the fluorescence F, the thickness of the condensing lens can be reduced. Thus, the size and weight of the particle detection device10can be reduced.

When the area to be measured is large, the adhesive surface12amay be entirely measured by scanning the optical system or the collection sheet12. Alternatively, as illustrated inFIG. 3, the number of particles that emit the fluorescence may be counted by picking up an image of the fluorescence with an image pickup element47such as a CCD (charge coupled device) or a CMOS (complementary metal oxide semiconductor) and counting the number of bright points.

Referring toFIG. 3, the particle detection device10according to the present embodiment further includes a movement mechanism51. The movement mechanism51moves the collection sheet12in the particle detection device10. The movement mechanism51moves the collection sheet12between the collection position81, the heating/cooling position82, and the fluorescence detection position83.

The movement mechanism51includes the sheet supply drum52, the sheet reception drum53, and a motor (not illustrated) that rotates these drums. The collection sheet12is hung between the sheet supply drum52and the sheet reception drum53. Both ends of the collection sheet12are respectively wounded around the sheet supply drum52and the sheet reception drum53. When the sheet supply drum52and the sheet reception drum53are rotated by driving the motor (not illustrated), the particles collected on the collection sheet12are moved between the collection position81, the heating/cooling position82, and the fluorescence detection position83.

According to the present invention, the collection sheet12is not necessarily contained in the form of a roll. For example, the collection sheet12folded into a plurality of layers may be contained.

FIG. 11is a perspective view for describing a method of replacing the collection sheet illustrated inFIG. 3. Referring toFIG. 11, the particle detection device10according to the present embodiment further includes a sheet cassette71serving as a housing.

The sheet cassette71has a housing shape that allows the sheet supply drum52or the sheet reception drum53to be contained therein. The collection sheet12wound into a roll is contained in the sheet cassette71. The particle detection device10includes two sheet cassettes71. The sheet supply drum52is contained in one of the sheet cassettes71and the sheet reception drum53is contained in the other sheet cassette71. The sheet cassette71can be detached from or attached to the particle detection device10by opening a lid73.

The collection sheet12has a sheet length sufficient to perform measurement a plurality of times. The collection sheet12having been used in measurement is rolled up on the sheet reception drum53so as to be collected. When measurement has been performed a predetermined number of times, the sheet cassettes71are replaced so that the sheet supply drum52around which a new collection sheet12is wound is attached to the device and the sheet reception drum53around which the collection sheet12having been used in the measurement is wound is removed from the device. In this case, the collection sheet12having been used in the measurement and on which the particles are attracted is wound into a roll. This prevents the particles from being removed, and accordingly, contamination of the device with the particles can be prevented. Thus, safe and easy replacement of the collection sheet12can be realized.

With the sheet cassettes71, the particles can be easily continuously measured without maintenance.

Next, the steps of a method of particle detection with the particle detection device10according to the present embodiment are described.

FIG. 12is a flowchart illustrating a flow of operations of the particle detection device illustrated inFIG. 3. Referring toFIG. 12, the collection step for the particles is initially performed at the collection position81(S101). In this step, by driving the fan23, the air outside the device is introduced into the collection barrel22. The air having been taken into the collection barrel22is blown to the adhesive surface12aof the collection sheet12, thereby the airborne particles are collected on the collection sheet12.

Next, the particles collected on the collection sheet12are moved from the collection position81to the fluorescence detection position83(S102). Next, the fluorescence detection unit41irradiates the particles with the excitation light, and the fluorescence emitted from the particles due to the irradiation of the particles with the excitation light is received. Thus, the fluorescent intensity of the particles before heating is measured (S103).

Next, the particles having undergone the measurement of the fluorescent intensity before heating are moved from the fluorescence detection position83to the heating/cooling position82(S104). Next, the heating unit31irradiates the particles with light so as to heat the particles. After that, the irradiation of the particles with the light is stopped so as to cool the particles. In the present embodiment, by driving the fan23at the collection position81in parallel with the heating/cooling step for the particles, particles for the next measurement are collected on the collection sheet12(S105).

Next, the particles having undergone the heating/cooling step are moved from the heating/cooling position82to the fluorescence detection position83(S106). In this step, the particles for the next measurement are moved from the collection position81to the heating/cooling position82. Next, the fluorescence detection unit41irradiates the particles with the excitation light, and the fluorescence emitted from the particles due to the irradiation of the particles with the excitation light is received. Thus, the fluorescent intensity of the particles after heating is measured (S107).

Next, the particles having undergone the measurement of the fluorescent intensity after heating are collected on the sheet reception drum53from the fluorescence detection position83(S108). At the same time as this, the particles for the next measurement prepared at the heating/cooling position82are moved to the fluorescence detection position83, and the fluorescent detection step before heating is performed.

By iterating the above-described steps, the biological particles can be continuously detected.

According to the present embodiment, the collection sheet12having low heat capacity is used so that the airborne particles are collected. Thus, heating and cooling time periods in the above-described heating/cooling step are reduced, and power consumed by the lamp32and the ceramic heater37can be reduced. Furthermore, since the particles can be heated by the heating device, the size and the cost of which are further reduced, the cost and the size of the particle detection device can be reduced.

Furthermore, according to the present embodiment, the collection step for the particles for the next measurement is performed in parallel with the heating/cooling step. Thus, a time period taken for continuous measurement can be further reduced. Here, the timing at which the particles for the next measurement are collected is not limited to the above-described heating/cooling step. The particles for the next measurement may instead be collected when, for example, the fluorescent intensity is measured after heating (S107).

According to the present embodiment, by measuring the difference in the amount of fluorescence before and after heating, an effect on the fluorescence produced by the particles other than the biological particles is canceled out. However, the present invention is not limited to this. For example, the fluorescence from biological particles may be identified as follows: only a state in which the fluorescence is increased after heating is picked up by the image pickup element, a threshold brightness value is set, and fluorescent points of brightness values equal to or more than a certain brightness value are determined as those of the biological particles.

The structure of the particle detection device10according to the embodiment of the present invention having been described above is summarized as follows: that is, the particle detection device10according to the present embodiment detects biological particles. The particle detection device10includes the collection sheet12, the collection unit21, the heating unit31, the fluorescence detection unit41, and the movement mechanism51. The collection sheet12serves as the sheet-shaped member. The collection unit21introduces airborne particles into the device so that the airborne particles are collected on the collection sheet12. The heating unit31heats the particles collected on the collection sheet12so as to increase the fluorescence emitted from the particles. The fluorescence detection unit41detects the fluorescence emitted from the particles which are collected on the collection sheet12. The movement mechanism51moves the collection sheet12.

With the particle detection device10according to the embodiment of the present invention, which has the above-described structure and in which the collection sheet12having small heat capacity is used for collecting the airborne particles, a measurement time period and the cost of measurement can be reduced.

The particle detection device10according to the present embodiment may be used as a standalone device for detecting biological particles or may be incorporated into a home appliance such as an air purifier, an air conditioner, a humidifier, a dehumidifier, a cleaner, a refrigerator, or a television set.

It should be understood that the embodiment disclosed herein is exemplary and not limiting in any sense. It is intended that the scope of the present invention is defined not by the above description but by the scope of the claims, and any modification within the meaning and the scope equivalent to the scope of the claims is included in the scope of the present invention.

INDUSTRIAL APPLICABILITY

The present invention is mainly utilized as a device that detects biological particles such as pollen, microorganisms, and molds.

REFERENCE SIGNS LIST