Particle detection device

A particle detection device detects a biological particle. The particle detection device includes a collection unit that collects a particle to a collection substrate, a fluorescence detection unit that emits excitation light toward the particle collected on the collection substrate and receives fluorescence emitted from the particle, and a cleaning unit that removes the particle from the collection substrate at a refreshing position separated from a collection/heating position and a detection position. At the collection/heating position, the particle is collected onto the collection substrate by the collection unit. At the detection position, fluorescence is received by the fluorescence detection unit. With such a structure, the particle detection device in which the particle is highly accurately detected is 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

As a related-art particle detection device, Japanese Unexamined Patent Application Publication No. 2002-357532, for example, discloses a measuring device for suspended particulate matter in order to simultaneously measure the densities of suspended particulate matter and pollen in the atmosphere (Patent Literature 1).

The measuring device disclosed in Patent Literature 1 includes a suspended particulate matter collection unit that collects suspended particulate matter in a sample gas onto filter paper, a suspended particulate matter detection unit that irradiates the suspended particulate matter on the filter paper with β-rays, measures the amount of β-ray transmission 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 measure the intensity of generated fluorescence so as to measure the amount of the pollen. The filter paper to which the suspended particulate matter has been collected is transported between the suspended particulate matter collection unit and a region where the suspended particulate matter detection unit and the pollen detection unit are disposed by using a filter paper transport mechanism, which includes rollers and motors combined to one another.

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

Technical Problem

As disclosed in the above-described Patent Literature, a known detection device measures the number of particles by irradiating the particles in air with ultraviolet rays and receiving fluorescence emitted from the particles. In such a particle detection device, a collection member such as a substrate is used to collect particles. However, when such a collection member is replaced with a new collection member every time measurement is performed, there is a problem in that the cost of particle detection is increased.

As a measure to solve such a problem, the collection member may be repeatedly used by cleaning the collection member when particle detection is completed. However, there is a concern over adverse effects on accuracy, with which the particles are detected, in the case where the particles removed from the collection member by cleaning are collected again to the collection member or adhere to optical systems for irradiation of ultraviolet rays or receiving fluorescence.

Accordingly, an object of the present invention is to solve the above-described problem and is to provide a particle detection device in which particles are highly accurately detected.

Solution to Problem

A particle detection device according to the present invention detects a biological particle. The particle detection device includes a collection unit that collects a particle to a collection member, a fluorescence detection unit that emits excitation light toward the particle collected to the collection member and receives fluorescence emitted from the particle, and a cleaning unit that removes the particle from the collection member at a third position separated from a first position and a second position. The particle is collected by the collection unit to the collection member at the first position. The fluorescence is received by the fluorescence detection unit at the second position.

In the particle detection device structured as described above, the particle is removed from the collection member by the cleaning unit at the third position separated from the first position and the second position. This can reduce a situation, in which the particle having been removed from the collection member reaches the first position or the second position. Accordingly, the particle detection device in which the particle is highly accurately detected can be realized.

Preferably, the collection member is moved among the first position, the second position, and the third position. In a movement direction of the collection member, when seen from the first position, the third position is located on a side opposite to a side where the second position is located.

In the particle detection device structured as described above, the third position, where the particle is removed from the collection member, and the second position, where the fluorescence is received by the fluorescence detection unit, are separated from each other. Thus, the particle can be highly accurately detected.

Preferably, the first position, the second position, and the third position are arranged on a circumference. In the particle detection device structured as described above, the collection unit, the fluorescence detection unit, and the cleaning unit can be arranged in a compact space.

Preferably, the first position, the second position, and the third position are arranged on a line. In the particle detection device structured as described above, the third position, where the particle is removed from the collection member, and the second position, where the fluorescence is received by the fluorescence detection unit, are further separated from each other. Thus, the particle can be more highly accurately detected.

Preferably, the collection member is moved among the first position, the second position, and the third position. A moving distance of the collection member between the second position and the third position is greater than a moving distance of the collection member between the first position and the third position.

In the particle detection device structured as described above, the third position, where the particle is removed from the collection member, and the second position, where the fluorescence is received by the fluorescence detection unit, are separated from each other. Thus, the particle can be highly accurately detected.

Preferably, the particle detection device further includes a heating unit that heats the particle, which has been collected to the collection member, at the first position. More preferably, the heating unit is disposed in the collection member. In the particle detection device structured as described above, by heating the particle collected to the collection member, a biological particle can be highly accurately detected.

Advantageous Effects of Invention

As described above, according to the present invention, the particle detection device that highly accurately detects the particle can be provided.

DESCRIPTION OF EMBODIMENTS

Embodiments of the present invention will be described with reference to the drawings. In the drawings to be referred to in the description below, the same components or components equal to the same components are denoted by the same reference numerals.

[Principle of Detection of Biological Particles]

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 (referred to as dust hereafter), which emit fluorescence similarly to biological particles, are also suspended. Thus, it is impossible to distinguish whether the light comes from biological particles or dust only by detecting fluorescence.

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 a mixed particle 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.

FIGS. 2 to 6illustrate steps of detecting biological particles. Referring toFIG. 2, particles are initially collected on a collection substrate510(collecting step).

In this step, the collection substrate510is disposed opposite an electrostatic stylus530and a potential difference is generated between the collection substrate510and the electrostatic stylus530. When air is introduced toward the collection substrate510by driving a fan500, airborne particles600around the electrostatic stylus530are charged. The charged particles600are attracted to a surface of the collection substrate510by electrostatic forces. The particles600collected on the collection substrate510includes biological particles600A and dust600B including, for example, lint of chemical fiber.

Next, referring toFIG. 3, the intensity of fluorescence emitted from the particles600before heating is measured (fluorescence measuring step (before heating)). In this step, the particles600collected on the collection substrate510is irradiated with excitation light emitted thereto from a light emitting element550such as a semiconductor laser, and fluorescence emitted from the particles600is received by a light receiving element565through a lens560.

Next, referring toFIG. 4, the particles600collected on the collection substrate510is heated by using a heater520. After the particles600have been heated, the collection substrate510is cooled (heating step).

Referring toFIG. 5, next, the intensity of fluorescence emitted from the particles600after heating is measured (fluorescence measuring step (after heating)). As has been described, the intensity of fluorescence emitted from the dust600B is not changed by heating, and the intensity of fluorescence emitted from the biological particles600A is increased by heating. Thus, the fluorescent intensity measured in this step is greater than that measured in the fluorescence measuring step (before heating) illustrated inFIG. 3.

FIG. 7is a graph illustrating the relationship between an increase ΔF in the fluorescent intensity after heating and the concentration of biological particles. Referring toFIG. 7, an increase ΔF1in the fluorescent intensity is calculated from the difference in the fluorescent intensity before and after heating. The 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 determined in advance.

Referring toFIG. 6, next, when detection of the biological particles of the particles600has been performed, the particles600are removed from the collection substrate510(refreshing step).

[General Structure of Particle Detection Device]

FIG. 8is a perspective view illustrating the appearance of the particle detection device according to a first embodiment of the present invention.FIG. 9is another perspective view illustrating the appearance of the particle detection device illustrated inFIG. 8.FIG. 10is an exploded view of the particle detection device illustrated inFIG. 8.FIG. 11is a perspective view illustrating an internal structure of the particle detection device illustrated inFIG. 8.

Referring toFIGS. 8 to 11, a particle detection device10according to the present embodiment includes a cabinet11serving as a housing, a fan16, a collection unit20, a fluorescence detection unit30, and a cleaning unit50.

The cabinet11has a substantially rectangular parallelepiped shape and houses the collection unit20, the fluorescence detection unit30, and the cleaning unit50. In the present embodiment, the cabinet11includes an upper cabinet12serving as a first housing and a lower cabinet14serving as a second housing. The lower cabinet14has a box shape having an opening on one side. The upper cabinet12has a flat-plate shape that closes the opening of the lower cabinet14. As an example, the dimensions of the cabinet11are 60 mm×50 mm (length and width of the upper cabinet12)×30 mm (height).

The cabinet11has side surfaces11mand11n, which oppose each other. The side surface11mis formed in the upper cabinet12and the side surface11nis formed in the lower cabinet14.

The cabinet11has a collection barrel15serving as a barrel-shaped member, which is integrally formed with the cabinet11. The collection barrel15opens at the side surface11mand extends so as to form a cylindrical shape from the side surface11mtoward the side surface11n. The collection barrel15surrounds an electrostatic stylus22, which will be described later. Air that includes particles is guided toward a collection substrate71, which is positioned so as to oppose the electrostatic stylus22, through the collection barrel15.

FIG. 12is a perspective view illustrating the particle detection device illustrated inFIG. 9with the fan detached. Referring toFIGS. 9 and 12, the fan16is rotatable in the forward and reverse directions. When the fan16is rotated in the forward direction, air in the cabinet11is discharged to the outside of the cabinet11through the fan16. When the fan16is rotated in the reverse direction, air is introduced from the outside of the cabinet11into the cabinet11through the fan16.

The fan16is attached to the side surface11nof the cabinet11. An opening120is formed at a position of the cabinet11where the fan16is attached. The opening120is opened so as to include a region opposite the collection barrel15(region indicated by a two-dot chain line122inFIG. 12) and a region opposite a brush51(region indicated by a two-dot chain line121inFIG. 12). The brush51will be described later. In the opening120, the region opposite the collection barrel15and the region opposite the brush51are continuous with each other.

With this structure, the fan16is used in the collecting step, for cooling in the heating step, and in the refreshing step. Thus, the size and the cost of the particle detection device10can be reduced.

Referring toFIGS. 8 to 11, the collection unit20performs the collecting step having been described with reference toFIG. 2, thereby collecting particles suspended in the air onto the collection substrate71. The collection unit20includes a high-voltage power source21serving as a power unit and the electrostatic stylus22serving as a discharge electrode.

The collection substrate71serves as a collection member. Mixed particles of biological particles and dust such as lint of chemical fiber are collected onto the collection substrate71. The collection substrate71is formed of a glass plate. An electrically conductive transparent film is formed on a surface of the glass plate that attracts the particles. The collection substrate71is not necessarily formed of a glass plate and may be formed of ceramic or metal. The film is not necessarily transparent. For example, a metal film may be formed on the surface of the collection substrate71formed of ceramic or the like. When the collection substrate71is formed of metal, the film is not necessarily formed on the surface of the collection substrate71.

The high-voltage power source21is the power unit used to generate a potential difference between the collection substrate71and the electrostatic stylus22.

The electrostatic stylus22extends from the high-voltage power source21, penetrates through the collection barrel15, and reaches the inside of the collection barrel15. In the collecting step, the collection substrate71opposes the electrostatic stylus22. In the present embodiment, the electrostatic stylus22is electrically connected to a positive electrode of the high-voltage power source21. The film formed on the collection substrate71is electrically connected to a negative electrode of the high-voltage power source21.

In the case where the electrostatic stylus22is electrically connected to the positive electrode of the high-voltage power source21, the film formed on the collection substrate71may be connected to a ground potential. Alternatively, the electrostatic stylus22may be electrically connected to the negative electrode of the high-voltage power source21and the film formed on the collection substrate71may be electrically connected to the positive electrode of the high-voltage power source21.

In the collecting step, when the fan16is rotated in the forward direction, air in the cabinet11is discharged and, at the same time, air outside the cabinet11is introduced toward the collection substrate71through the collection barrel15. In so doing, by generating the potential difference between the electrostatic stylus22and the collection substrate71by using the high-voltage power source21, airborne particles around the electrostatic stylus22are positively charged. The positively charged particles are moved to the collection substrate71by electrostatic forces and attracted to the electrically conductive film, thereby being collected onto the collection substrate71.

As described above, in the particle detection device10according to the present embodiment, the particles are collected onto the collection substrate71by electrostatic collection that utilizes electrostatic forces. In this case, the particles can be reliably held on the collection substrate71during detection of the particles, and after the particles have been detected, the particles can be easily removed from the collection substrate71.

By using the needle-shaped electrostatic stylus22as the discharge electrode, the charged particles can be attracted to a very narrow region of the surface of the collection substrate71opposite the electrostatic stylus22, the region corresponding to a region irradiated with the light emitting element, which will be described later. Thus, in the fluorescence measuring step, microorganisms having been attracted can be efficiently detected.

The fluorescence detection unit30performs the fluorescence measuring steps (before and after heating) having been described with reference toFIGS. 3 and 5. The fluorescence detection unit30includes an excitation light source unit31and light receiving unit41. The excitation light source unit31emits excitation light toward the particles collected on the collection substrate71. The light receiving unit41receives fluorescence emitted from the particles as the particles are irradiated with the excitation light.

The excitation light source unit31includes a light emitting element32serving as a light source, an excitation unit frame33, a condensing lens34, and a lens pressing member35. The light receiving unit41includes a noise shield42, an amplification circuit43, a light receiving element44, a light receiving unit frame45, a Fresnel lens46, and a lens pressing member47. The light emitting element32uses, for example, a semiconductor laser or an LED (light emitting diode) element. The wavelength of light emitted from the light emitting element32may 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 fluorescent. The light receiving element44uses, for example, a photodiode or an image sensor.

The cleaning unit50performs the refreshing step having been described with reference toFIG. 6, thereby removing the particles from the collection substrate71. The cleaning unit50includes the brush51as a cleaning device, a brush securing portion52as a base portion, and a brush pressing member53. The cleaning unit50is secured to and supported by the high-voltage power source21. The cleaning unit50remains stationary during the refreshing step.

The brush51is formed of a fiber assembly. The brush51is formed of an electrically conductive fiber assembly. The brush51is formed of, for example, a carbon fiber. It is preferable that the wire diameter of the fiber assembly of the brush51be from φ0.05 mm to φ0.2 mm.

The brush51has a free end51pand a supported end51q(seeFIG. 11). The supported end51qis disposed at an end portion opposite to the free end51p. The supported end51qis supported by the brush securing portion52and the brush pressing member53. The brush51hangs down with the supported end51qat the top and the free end51pat the bottom. The brush51is secured and supported at a refreshing position93, which will be described later. By moving the collection substrate71while the free end51pof the brush51is in contact with the surface of the collection substrate71, the particles are removed from the collection substrate71.

Although a collection device that removes particles from the collection substrate71uses the brush51in the present embodiment, the present invention is not limited to this. For example, the collection device may be a flat plate-shaped wiper to be brought into contact with the surface of the collection substrate71or a nozzle, through which air is blown toward the surface of the collection substrate71.

The particle detection device10further includes a heater76serving as a heating unit and a movement mechanism60.

The heater76performs the heating step having been described with reference toFIG. 4, thereby heating the particles collected on the collection substrate71.

The movement mechanism60, to which the collection substrate71is attached, moves the collection substrate71in the collecting step, the fluorescence measuring steps (before and after heating), the refreshing step, and the heating step. The movement mechanism60includes a motor holder61, a rotating motor62, a motor pressing member63, and a rotating base64. The rotating motor62serves as a rotatable drive unit. The rotating base64serves as an arm unit.

FIG. 13is a perspective view illustrating the rotating base of the movement mechanism.FIG. 14is an exploded view of the rotating base illustrated inFIG. 13.FIG. 13illustrates the rotating base64when seen from a rear side (side surface11nside of the cabinet11).FIG. 14illustrates the rotating base64when seen from a front side (side surface11mside of the cabinet11).

Referring toFIGS. 11,13, and14, an output shaft of the rotating motor62is connected to the rotating base64. As the rotating motor62rotates, the rotating base64rotates (in the forward and reverse directions) about a rotational axis66illustrated by a phantom line inFIG. 11.

The rotating base64is formed of a resin material. The rotating base64has the following portions: a central portion67, a substrate supporting portion68, a brush cleaning arm81serving as a cleaning device initializing member, and a sensing target portion82.

The central portion67is connected to the output shaft of the rotating motor62. The central portion67is rotatably supported by the cabinet11about the rotational axis66. The substrate supporting portion68extends from the central portion67in the radial direction of the rotational axis66. The collection substrate71is attached to the tip of the substrate supporting portion68. Part of the substrate supporting portion68, the part being a part to which the collection substrate71is attached, has a frame shape. The details of the brush cleaning arm81and the sensing target portion82will be described later.

The heater76is bonded to the rear surface of the collection substrate71. The heater76is moved together with the collection substrate71when the rotating base64is rotated. A plurality of wires111,112, and113are connected to the heater76. The wires111,112, and113include a power supply line of the heater76and a signal line of a sensor disposed in the heater76. The wires111,112, and113are led to the outside of the cabinet11through a flexible printed circuit96.

FIG. 15is a sectional view of the particle detection device in the collecting step and the heating step.FIG. 16is a sectional view of the particle detection device in the fluorescence measuring steps (before and after heating).

FIG. 17is a sectional view of the particle detection device in the refreshing step.FIGS. 15 to 17are the sectional views of the particle detection device seen from the side surface11nside of the cabinet11.

Referring toFIGS. 15 to 17, in the particle detection device10according to the present embodiment, the collection substrate71is moved to a collection/heating position91illustrated inFIG. 15as a first position in the collecting step and the heating step, moved to a detection position92illustrated inFIG. 16as a second position in the fluorescence measuring steps (before and after heating), and moved to the refreshing position93illustrated inFIG. 17as a third position in the refreshing step. The collection/heating position91, the detection position92, and the refreshing position93are separated from one another.

It is noted that the refreshing position93illustrated inFIG. 17is a representative example of the refreshing position93. In the actual refreshing step, the brush51is brought into contact with the surface of the collection substrate71while the collection substrate71is being moved, thereby removing the particles on the collection substrate71. Thus, a movement range of the collection substrate71where the collection substrate71and the brush51are in contact with each other corresponds to the refreshing position93.

The collection substrate71is held in a single plane while being moved among the collection/heating position91, the detection position92, and the refreshing position93. The collection substrate71is held in the single plane perpendicular to the rotational axis66while being moved among the collection/heating position91, the detection position92, and the refreshing position93.

That is, the particle detection device10according to the present embodiment includes the movement mechanism60, which held the collection substrate71in the single plane while moving the collection substrate71among the collection/heating position91, the detection position92, and the refreshing position93. Since the collection substrate71is moved in the single plane in the present embodiment, positioning accuracy of the collection substrate71can be improved at the collection/heating position91, the detection position92, and the refreshing position93. Furthermore, since the collection substrate71is not moved in the axial direction of the rotational axis66, the entire height of the particle detection device10can be reduced.

The collection/heating position91, the detection position92, and the refreshing position93are located on a circumference. The collection/heating position91, the detection position92, and the refreshing position93are arranged on the circumference about the rotational axis66. In the movement direction of the collection substrate71, the collection/heating position91is located between the detection position92and the refreshing position93. In other words, in the movement direction of the collection substrate71, the refreshing position93is located on a side of the collection/heating position91opposite to a side where the detection position92is located. In the movement direction of the collection substrate71, the detection position92, the collection/heating position91, and the refreshing position93are arranged in this order.

The moving distance of the collection substrate71between the detection position92and the refreshing position93is greater than that between the collection/heating position91and the refreshing position93. The movement range of the collection substrate71about the rotational axis66among the collection/heating position91, the detection position92, and the refreshing position93is equal to or smaller than 180°.

Next, operation of the particle detection device10according to the present embodiment is described.FIG. 18is a flowchart illustrating the flow of operation of the particle detection device according to the first embodiment of the present invention.

In the following description, a clockwise rotation about the rotational axis66inFIGS. 15 to 17is referred to as a forward direction and a counterclockwise rotation about the rotational axis66inFIGS. 15 to 17is referred to as a reverse direction.

Referring toFIGS. 15 and 18, the collection substrate71is initially positioned at the collection/heating position91so as to perform the collecting step (S101). In so doing, air is introduced into the cabinet11by rotating the fan16in the forward direction, and airborne particles are collected onto the surface of the collection substrate71by generating a potential difference between the electrostatic stylus22and the collection substrate71using the high-voltage power source21.

Next, referring toFIGS. 16 and 18, the rotating base64is rotated in the forward direction by driving the rotating motor62, thereby moving the collection substrate71from the collection/heating position91to the detection position92(S102). Next, the excitation light source unit31emits excitation light toward the particles collected on the collection substrate71, and fluorescence emitted from the particles irradiated with the excitation light is received by the light receiving unit41. By doing this, the fluorescent intensity of the particles collected on the collection substrate71before heating is measured (S103).

Next, referring toFIGS. 15 and 18, the rotating base64is rotated in the reverse direction by driving the rotating motor62, thereby moving the collection substrate71from the detection position92to the collection/heating position91(S104). Next, by supplying power to the heater76, the particles collected on the collection substrate71are heated (S105). Next, by stopping the power supply to the heater76, the collection substrate71is cooled (S106). In so doing, by driving the fan16in the reverse direction, the air is introduced into the cabinet11, thereby facilitating cooling of the collection substrate71.

Next, referring toFIGS. 16 and 18, the rotating base64is rotated in the forward direction by driving the rotating motor62, thereby moving the collection substrate71from the collection/heating position91to the detection position92(S107). Next, the excitation light source unit31emits the excitation light toward the particles collected on the collection substrate71, and the fluorescence emitted from the particles irradiated with the excitation light is received by the light receiving unit41. By doing this, the fluorescent intensity of the particles collected on the collection substrate71after heating is measured (S108).

Next, referring toFIGS. 17 and 18, the rotating base64is rotated in the reverse direction by driving the rotating motor62, thereby moving the collection substrate71from the detection position92to the refreshing position93. The rotating base64is rotated in the reverse direction and rotated in the forward direction at the refreshing position93, thereby bringing the surface of the collection substrate71into contact with the brush51. By doing this, the particles are removed from the collection substrate71(S109).

In the refreshing step, by driving the fan16in the forward direction, the particles removed from the collection substrate71and flying in the air are discharged to the outside of the cabinet11through the opening120. In order to collect the particles discharged to the outside of the cabinet11through the opening120, it is preferable that a filter be provided between the opening120and the fan16.

In so doing, as the collection substrate71approaches from the collection/heating position91illustrated in FIG.15to the refreshing position93illustrated inFIG. 17, a region where the collection substrate71and the collection barrel15are superposed with each other is decreased. Accordingly, the area of an opening of the collection barrel15as an air inlet is increased. Thus, the particles can be efficiently collected at the outside the cabinet11. In contrast, in the collecting step, the area of the opening of the collection barrel15is reduced by being blocked by the collection substrate71. Thus, losses in air introduction can be reduced.

In the present embodiment, the refreshing step is performed by causing the cleaning unit50to remain stationary and moving the collection substrate71. Accordingly, a separate movement mechanism for performing the refreshing step is not needed. Thus, the size and the cost of the particle detection device10can be reduced.

Referring toFIGS. 15 and 18, the rotating base64is rotated in the forward direction by driving the rotating motor62, thereby moving the collection substrate71from the refreshing position93to the collection/heating position91(S110). By repeating the above-described steps S101to S110, the biological particles are continuously detected.

The structure of the particle detection device according to the first embodiment of the present invention having been described is summarized as follows. That is, the particle detection device10according to the present embodiment detects biological particles. The particle detection device10includes the collection unit20, the fluorescence detection unit30, and the cleaning unit50. The collection unit20collects particles onto the collection substrate71that serves as the collection member. The fluorescence detection unit30emits excitation light toward the particles collected on the collection substrate71and receives fluorescence emitted from the particles. The cleaning unit50removes the particles from the collection substrate71at the refreshing position93as the third position. The refreshing position93is separated from the collection/heating position91as the first position and the detection position92as the second position. At the collection/heating position91, the particles are collected onto the collection substrate71by the collection unit20. At the detection position92, the fluorescence is received by the fluorescence detection unit30.

In addition, the particle detection device10according to the present embodiment detects biological particles. The particle detection device10includes the collection unit20, the fluorescence detection unit30, the cleaning unit50, and the movement mechanism60. The collection unit20collects particles onto the collection substrate71that serves as the collection member. The fluorescence detection unit30emits excitation light toward the particles collected on the collection substrate71and receives fluorescence emitted from the particles. The cleaning unit50removes the particles from the collection substrate71. The movement mechanism60moves the collection substrate71among the collection/heating position91as the first position, the detection position92as the second position, and the refreshing position93as the third position. At the collection/heating position91, the particles are collected onto the collection substrate71by the collection unit20. At the detection position92, the fluorescence is received by the fluorescence detection unit30. At the refreshing position93, the cleaning unit50removes the particles from the collection substrate71.

In addition, the particle detection device10according to the present embodiment detects biological particles. The particle detection device10includes the collection unit20, the fluorescence detection unit30, and the cleaning unit50. The collection unit20collects particles onto the collection substrate71that serves as the collection member. The fluorescence detection unit30emits excitation light toward the particles collected on the collection substrate71and receives fluorescence emitted from the particles. The cleaning unit50removes the particles from the collection substrate71. The collection substrate71is rotated in the forward and reverse directions, thereby being moved among the collection/heating position91as the first position, the detection position92as the second position, and the refreshing position93as the third position. At the collection/heating position91, the particles are collected onto the collection substrate71by the collection unit20. At the detection position92, the fluorescence is received by the fluorescence detection unit30. At the refreshing position93, the cleaning unit50removes the particles from the collection substrate71.

In the present embodiment, the cleaning unit50is provided for removing particles from the collection substrate71. This allows the collection substrate71to be repeatedly used to detect biological particles. Thus, in comparison with the case where the collection substrate71is replaced every time a detection operation is performed, the cost required for particle detection can be reduced.

In the present embodiment, the refreshing step, in which particles are removed from the collection substrate71, is performed at the refreshing position93separated from the collection/heating position91and the detection position92. This can prevent the occurrence of the following situations: the particles having been removed from the collection substrate71are collected again to the collection substrate71in the next collecting step; and the particles having reached the detection position92from the collection substrate71adhere to optical systems such as the light emitting element32and the light receiving element44. In particular, the collection/heating position91is located so as to separate the refreshing position93and the detection position92from each other in the present embodiment. This can effectively prevent the particles having been removed from the collection substrate71from reaching the detection position92. For these reasons, biological particles can be highly accurately detected with the particle detection device10according to the present embodiment.

In the present embodiment, the collection/heating position91, the detection position92, and the refreshing position93are arranged on a circumference. Thus, the collection substrate71is moved among these positions by being rotated. With such a structure, the collection unit20, the fluorescence detection unit30, and the cleaning unit50can be arranged in a compact space, and accordingly, the size of the particle detection device10can be reduced. Furthermore, the collection substrate71is rotated in the forward and reverse directions so as to be moved to the collection/heating position91, detection position92, and the refreshing position93in the present embodiment. This prevents entanglement of a plurality of wires led through the flexible printed circuit96and wires for electrostatic collection.

The structure of the heater76as the heating unit is summarized as follows. That is, the particle detection device10according to the present embodiment includes the heater76as the heating unit that heats particles collected on the collection substrate71. Biological particles are detected by the difference between the intensity of fluorescence emitted from the particles before heating and the intensity of fluorescence emitted from the particles after heating. The fluorescent intensity is measured by the fluorescence detection unit30. When the particles are heated by the heater76, the collection substrate71is moved to the collection/heating position91as the first position. The heater76is moved together with the collection substrate71by the movement mechanism60. The collection substrate71having been heated by the heater76is cooled by air introduced into the cabinet11by the fan16.

In the present embodiment, the heating step, in which particles collected on the collection substrate71is heated, is performed at the same position (collection/heating position91) as that of the collecting step, in which the particles are collected onto the collection substrate71. Thus, the size of the particle detection device10can be reduced. Furthermore, by disposing the heater76on the movement mechanism60and moving the heater76together with the collection substrate71, the structure of the particle detection device10can be simplified.

[Arrangement of Components of Particle Detection Device]

Referring toFIG. 11andFIGS. 15 to 17, in the present embodiment, the components of the collection unit20, the fluorescence detection unit30, and the cleaning unit50are arranged in the circumferential direction about the rotational axis66.

The collection barrel15and the electrostatic stylus22oppose the collection/heating position91. The high-voltage power source21and the cleaning unit50oppose the refreshing position93. The light receiving unit41opposes the detection position92.

The collection barrel15and the light receiving unit41are adjacent to each other in the circumferential direction about the rotational axis66. The excitation light source unit31is adjacent to the light receiving unit41on a side opposite to a side where the collection barrel15is disposed in the circumferential direction about the rotational axis66. That is, the light receiving unit41is disposed between the excitation light source unit31and the collection barrel15in the circumferential direction about the rotational axis66. The excitation light source unit31is disposed on a side opposite to a side where the collection barrel15is disposed with the rotational axis66interposed therebetween.

The high-voltage power source21is adjacent to the collection barrel15on a side opposite to a side where the light receiving unit41is disposed in the circumferential direction about the rotational axis66. That is, the collection barrel15is disposed between the high-voltage power source21and the light receiving unit41in the circumferential direction about the rotational axis66. The high-voltage power source21is disposed on a side opposite to a side where the light receiving unit41is disposed with the rotational axis66interposed therebetween. The high-voltage power source21and the excitation light source unit31are adjacent to each other in the circumferential direction about the rotational axis66.

When seen in the axial direction of the rotational axis66, the collection barrel15, the light receiving unit41, and the high-voltage power source21are superposed with the movement range of the collection substrate71about the rotational axis66. When seen in the axial direction of the rotational axis66, the excitation light source unit31is shifted from the movement range of the collection substrate71about the rotational axis66.

In the present embodiment, the excitation light source unit31is disposed opposite to the collection barrel15relative to the light receiving unit41in the movement direction of the collection substrate71. With such a structure, an increase in the distance between the collection/heating position91and the detection position92due to arrangement of the excitation light source unit31is prevented.

When seen in the axial direction of the rotational axis66, the cleaning unit50is superposed with the high-voltage power source21. More specifically, the brush securing portion52of the cleaning unit50is attached to the high-voltage power source21. As illustrated inFIG. 11, the excitation light source unit31and the light receiving unit41respectively have a height H1(length in the axial direction of the rotational axis66) and a height H2. The high-voltage power source21has a height H3. The height H3is smaller than the height H1and the height H2, and the height H1is greater than the height H2(H3<H2<H1).

In the present embodiment, the cleaning unit50is superposed with the high-voltage power source21, which has the smallest height among the excitation light source unit31, the light receiving unit41, and the high-voltage power source21. Thus, the components of the collection unit20, the fluorescence detection unit30, and the cleaning unit50are efficiently arranged in a limited space in the cabinet11.

In the present embodiment, the cleaning unit50and the collection barrel15are adjacent to each other in the circumferential direction about the rotational axis66. With such a structure, the fan16can be used in the collecting step, for cooling in the heating step, and in the refreshing step.

FIG. 19is a perspective view illustrating an internal structure of the particle detection device. Referring toFIG. 19, the collection barrel15and the movement mechanism60are provided so as to separate the light receiving unit41and the excitation light source unit31from the cleaning unit50.

Such a structure can effectively reduce a situation in which particles having been removed from the collection substrate71at the refreshing position93reach the detection position92. Furthermore, there is no need of providing partitions in the cabinet11in order to prevent the particles from reaching from the refreshing position93to the detection position92, and accordingly, the collection/heating position91, the detection position92, and the refreshing position93can be located in a single space in the cabinet11. Thus, the size of the particle detection device10can be reduced.

In the refreshing step, as the particles are removed from the collection substrate71by the cleaning unit50, the particles adhere to the brush51in contact with the surface of the collection substrate71. The particle detection device10according to the present embodiment includes the brush cleaning arm81serving as the cleaning device initializing member. The particles that adhere to the brush51are removed by the brush cleaning arm81.

Referring toFIGS. 13 and 14, the brush cleaning arm81is integrated with the rotating base64. The brush cleaning arm81is moved together with the collection substrate71when the rotating base64is rotated. The brush cleaning arm81extends in the radial direction of the rotational axis66from the central portion67of the rotating base64. The particles adhering to the brush51are removed by rotating the brush cleaning arm81while the brush cleaning arm81is in contact with the free end51pof the brush51.

The brush cleaning arm81is disposed at a position shifted from the substrate supporting portion68in the circumferential direction about the rotational axis66. As illustrated inFIG. 16, when the collection substrate71has been moved to the detection position92, the brush cleaning arm81is positioned between the collection substrate71and the brush51.

FIGS. 20 to 22are sectional views illustrating the movements of the collection substrate and the brush cleaning arm in the refreshing step. InFIG. 22, an end of the movement range of the collection substrate71in the refreshing step is illustrated.

Referring toFIGS. 20 to 22, after the fluorescent intensity of the particles after heating have been measured, the rotating base64is rotated in the reverse direction, thereby moving the collection substrate71from the detection position92to the refreshing position93.

In so doing, the particles adhering to the brush51are removed initially by moving the brush cleaning arm81in the reverse direction while the brush cleaning arm81is in contact with the free end51pof the brush51. At the same time, the particles having been removed from the brush51are collected from the refreshing position93to the outside of the cabinet11by driving the fan16in the forward direction. The rotating base64is further rotated in the reverse direction so as to cause the surface of the collection substrate71to be brought into contact with the brush51, thereby removing the particles from the collection substrate71. When the collection substrate71has been moved to the end of the movement range illustrated inFIG. 22, the rotating base64is rotated in the forward direction so as to cause the surface of the collection substrate71to be brought into contact with the brush51again, thereby removing the particles from the collection substrate71.

In the present embodiment, when the collection substrate71has been moved to the detection position92, the brush cleaning arm81is positioned between the collection substrate71and the brush51. Thus, the brush cleaning arm81is brought into contact with the brush51before the collection substrate71is brought into contact with the brush51. Accordingly, the collection substrate71can be cleaned by the brush51, which has been refreshed with the brush cleaning arm81. Thus, the particles can be efficiently removed from the collection substrate71.

Furthermore, the brush cleaning arm81is integrated with the rotating base64, to which the collection substrate71is attached. With such a structure, a separate movement mechanism for moving the brush cleaning arm81is not required. Thus, the size and the cost of the particle detection device10can be reduced.

Furthermore, a particle capturing portion having adhesiveness may be provided in the cabinet11. The particle capturing portion is formed of, for example, an adhesive sheet. Preferably, the particle capturing portion is provided at the refreshing position93or a position between the refreshing position93and the collection/heating position91. With such a structure, in addition to collection of the particles by driving the fan16, the particles removed from the collection substrate71or the brush51can be collected by the particle capturing portion.

FIG. 23illustrates height relationships among the brush, the brush cleaning arm, and the collection substrate. Referring toFIG. 23, the brush cleaning arm81and the collection substrate71respectively have top surfaces81aand71ato be in contact with the free end51pof the brush51. When, with reference to a given position, the height of the free end51pof the brush51is defined as H6, the height of the top surface81aof the brush cleaning arm81is defined as H7, and the height of the top surface71aof the collection substrate71is defined as H8, it is preferable that the following relationship be satisfied: H6<H8<H7.

[Detailed Structure of Particle Detection Device]

The particle detection device10according to the present embodiment includes a position sensor77, a position sensor78, and the sensing target portion82. The position sensors77and78serve as position detection units that detect the position of the collection substrate71.

Referring toFIGS. 11,15, and16, the position sensors77and78detect the position of the collection substrate71by detecting that the sensing target portion82comes to the proximity of the position sensor77or78. The position sensors77and78are attached to inner walls of the cabinet11. The position sensors77and78are provided in a single plane perpendicular to the rotational axis66. When seen in the axial direction of the rotational axis66, the position sensor77is disposed between the collection/heating position91and the detection position92, and the position sensor78is disposed between the collection/heating position91and the refreshing position93.

Referring toFIG. 13, the sensing target portion82is integrated with the rotating base64. The sensing target portion82is moved together with the collection substrate71when the rotating base64is rotated. The sensing target portion82is provided at the tip of the brush cleaning arm81that extends from the central portion67of the rotating base64in the radial direction of the rotational axis66.

Referring toFIGS. 11,15, and16, a controller (not shown) detects that, when the position sensor78detects that the sensing target portion82comes to the proximity of the position sensor78, the collection substrate71is positioned at the collection/heating position91. At this time, the controller issues a command to the collection unit20and the fan16so as to start collection of particles onto the collection substrate71. Furthermore, the controller detects that, when the position sensor77detects that the sensing target portion82comes to the proximity of the position sensor77, the collection substrate71is positioned at the detection position92. At this time, the controller issues an instruction to the fluorescence detection unit30so as to start detection of biological particles.

With the detection of the position of the collection substrate71by using the position sensors77and78, positional accuracy of the collection substrate71in the collecting step and the detecting step can be improved, and accordingly, repeatability of the detection of the biological particles can be improved.

Referring toFIG. 16, the particle detection device10according to the present embodiment includes a projecting portion19, which is disposed at the end of the movement range of the movement mechanism60and serves as a regulating member that regulates the movement of the movement mechanism60. The projecting portion19projects from an inner wall of the cabinet11. The projecting portion19is adjacent to the detection position92. When the collection substrate71has been moved to the detection position92, the rotating base64is brought into contact with the projecting portion19. Thus, a further movement of the rotating base64is regulated.

The particle detection device10according to the present embodiment may be used as a single device that detects biological particles, or may be incorporated in a home appliance such as an air cleaner, an air conditioner, a humidifier, a dehumidifier, a cleaner, a refrigerator, or a television set.

FIG. 24is a plan view illustrating a particle detection device according to a second embodiment of the present invention.FIG. 25is a side view of the particle detection device illustrated inFIG. 24. The particle detection device according to the present embodiment basically has similar structures compared to those of the particle detection device10according to the first embodiment. Duplicate structures are not repeatedly described in the following description.

Referring toFIGS. 24 and 25, in the particle detection device according to the present embodiment, the collection/heating position91, the detection position92, and the refreshing position93are arranged on a line. The collection substrate71attached to a movement mechanism (not shown) is moved among the collection/heating position91, the detection position92, and the refreshing position93while being reciprocated in a direction indicated by a double-headed arrow131. By the reciprocation of the collection substrate71in a double-headed arrow132direction at the refreshing position93, particles collected on the collection substrate71are removed.

In the movement direction of the collection substrate71, the collection/heating position91is located between the detection position92and the refreshing position93. In other words, in the movement direction of the collection substrate71, the refreshing position93is located on a side of the collection/heating position91opposite to a side where the detection position92is located. In the movement direction of the collection substrate71, the detection position92, the collection/heating position91, and the refreshing position93are arranged in this order.

In the present embodiment, the collection/heating position91, the detection position92, and the refreshing position93are arranged on a line. Thus, compared to the first embodiment in which these positions are arranged on a circumference, the distance between the detection position92and the refreshing position93can be increased. This can effectively prevent a situation in which particles having been removed from the collection substrate71at the refreshing position93from reaching the detection position92.

The collection unit20, the fluorescence detection unit30, and the cleaning unit50are configured such that the detection position92is located between the collection/heating position91and the refreshing position93in the movement direction of the collection substrate71.

Industrial Applicability

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

Reference Signs List