WO2015151502A1 - Particle-detecting sensor, dust sensor, smoke detector, air purifier, fan, and air conditioner - Google Patents

Particle-detecting sensor, dust sensor, smoke detector, air purifier, fan, and air conditioner Download PDF

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Publication number
WO2015151502A1
WO2015151502A1 PCT/JP2015/001835 JP2015001835W WO2015151502A1 WO 2015151502 A1 WO2015151502 A1 WO 2015151502A1 JP 2015001835 W JP2015001835 W JP 2015001835W WO 2015151502 A1 WO2015151502 A1 WO 2015151502A1
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WO
WIPO (PCT)
Prior art keywords
light
detection sensor
particle
light receiving
particle detection
Prior art date
Application number
PCT/JP2015/001835
Other languages
French (fr)
Japanese (ja)
Inventor
辻　幸司
渡部　祥文
修 赤坂
弘貴 松浪
福島　博司
貴司 中川
吉祥 永谷
圭子 川人
友洋 中谷
雄一 稲葉
Original Assignee
パナソニックＩｐマネジメント株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP2014078774A external-priority patent/JP2015200547A/en
Priority claimed from JP2014169906A external-priority patent/JP2015200629A/en
Priority claimed from JP2014169907A external-priority patent/JP2016045093A/en
Application filed by パナソニックＩｐマネジメント株式会社 filed Critical パナソニックＩｐマネジメント株式会社
Publication of WO2015151502A1 publication Critical patent/WO2015151502A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/47—Scattering, i.e. diffuse reflection
    • G01N21/49—Scattering, i.e. diffuse reflection within a body or fluid
    • G01N21/53—Scattering, i.e. diffuse reflection within a body or fluid within a flowing fluid, e.g. smoke
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume, or surface-area of porous materials
    • G01N15/06—Investigating concentration of particle suspensions
    • G01N15/075—
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume, or surface-area of porous materials
    • G01N2015/0042—Investigating dispersion of solids
    • G01N2015/0046—Investigating dispersion of solids in gas, e.g. smoke
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2201/00—Features of devices classified in G01N21/00
    • G01N2201/06—Illumination; Optics
    • G01N2201/064—Stray light conditioning
    • G01N2201/0642—Light traps; baffles

Definitions

  • the present invention relates to a particle detection sensor and a device having a particle detection sensor, such as a dust sensor, a smoke detector, an air cleaner, a ventilation fan, or an air conditioner. More specifically, the present invention relates to a light-scattering particle detection sensor that detects particles (aerosol) floating in the atmosphere using scattered light of the particles, and an apparatus such as an air purifier using the same.
  • a particle detection sensor such as a dust sensor, a smoke detector, an air cleaner, a ventilation fan, or an air conditioner. More specifically, the present invention relates to a light-scattering particle detection sensor that detects particles (aerosol) floating in the atmosphere using scattered light of the particles, and an apparatus such as an air purifier using the same.
  • the light scattering particle detection sensor is a photoelectric sensor including a light projecting element and a light receiving element, takes in a gas to be measured, irradiates the light of the light projecting element, and is contained in the gas by the scattered light. It detects the presence or absence of particles. For example, particles such as dust, pollen, and smoke floating in the atmosphere can be detected.
  • the method using the heater resistance has a low flow rate and cannot accurately detect fine particles having a small particle size.
  • the present invention has been made in view of such problems, and provides a particle detection sensor or the like that can detect fine particles with high accuracy even in a heating method in which an air flow is generated by a heating device such as a heater resistor. Is the first purpose.
  • particles are detected by introducing gas containing particles such as dust, pollen, smoke, etc., so that the particles adhere to the inside of the particle detection sensor and the detection accuracy decreases. There is a case.
  • This invention is made in view of such a subject, and makes it the 2nd objective to provide the particle
  • Patent Documents 2 and 3 a technique for promoting introduction of air into the sensor by a heater is known (for example, Patent Documents 2 and 3).
  • a shielding plate is further provided inside the housing in order to shield direct light from the air inlet and the air outlet.
  • a maze is provided in the particle flow path so that external light does not directly enter from the air inlet and the air outlet.
  • the present invention has been made in view of such problems, and a third object thereof is to provide a particle detection sensor or the like that can improve the detection accuracy of particles.
  • one aspect of the first particle detection sensor includes a light projecting element and a light receiving element, and light scattered from the light projecting element by particles in a detection region.
  • a particle detection sensor for detecting particles contained in a gas by receiving light by the light receiving element, a heating device for heating the gas, and a reflection for reflecting the scattered light and guiding the scattered light to the light receiving element And having a body.
  • one aspect of the second particle detection sensor is a housing, a light projecting element disposed in the housing, and a housing in the housing. And a light receiving element that receives scattered light of the light projecting element due to particles in the detection region, and a space that is provided in the housing and that includes the detection region and flows through the atmosphere including particles.
  • a particle channel that is a region, a light receiving region that is provided in the housing and is a space region for guiding the scattered light to the light receiving element, and a connection portion between the particle channel and the light receiving region
  • a first protective plate having translucency.
  • an aspect of a third particle detection sensor is a light-receiving element and receives light scattered from the light-projecting element by particles in a detection region.
  • the scattered light has a shape that suppresses reflection of the scattered light to the detection region.
  • fine particles can be detected with high accuracy even with a heating method in which an air flow is generated by a heating device such as a heater resistor.
  • the second particle detection sensor it is possible to suppress the adhesion of particles inside the particle detection sensor, and thus it is possible to suppress a decrease in detection accuracy.
  • stray light can be suppressed, so that the particle detection accuracy can be improved.
  • FIG. 1A is a top view of the particle detection sensor according to Embodiment 1
  • FIG. 1B is a front view of the particle detection sensor
  • FIG. 1C is a view of the particle detection sensor.
  • FIG. 1D is a bottom view
  • FIG. 1D is a cross-sectional view of the particle detection sensor taken along line AA in FIG.
  • FIG. 2A is a cross-sectional view for explaining the operation of the particle detection sensor when there is no particle in the gas.
  • FIG. 2B is a cross-sectional view for explaining the operation of the particle detection sensor when there are particles having a small particle diameter in the gas.
  • FIG. 2C is a cross-sectional view for explaining the operation of the particle detection sensor when particles having a large particle diameter are present in the gas.
  • FIG. 1A is a top view of the particle detection sensor according to Embodiment 1
  • FIG. 1B is a front view of the particle detection sensor
  • FIG. 1C is a view of the particle detection sensor.
  • FIG. 3 is a cross-sectional view of the particle detection sensor of Comparative Example 1.
  • FIG. 4 is a cross-sectional view of the particle detection sensor according to the first embodiment.
  • FIG. 5 is a diagram for explaining the positional relationship among the reflector, the light receiving element, and the detection region in the particle detection sensor according to the first embodiment.
  • 6 (a) is a top view of the particle detection sensor according to Embodiment 2
  • FIG. 6 (b) is a front view of the particle detection sensor
  • FIG. 6 (c) is the particle detection sensor.
  • FIG. 6D is a bottom view
  • FIG. 6D is a cross-sectional view of the particle detection sensor taken along line AA in FIG. FIG.
  • FIG. 7 is a diagram for explaining a positional relationship among a reflector, a light projecting element, a light receiving element, and a detection region in the particle detection sensor according to the second embodiment.
  • FIG. 8A is an enlarged cross-sectional view showing a configuration around a first light shield in the particle detection sensor according to Embodiment 2.
  • FIG. 8B is an enlarged cross-sectional view illustrating a configuration around a second light shielding body in the particle detection sensor according to Embodiment 2.
  • FIG. 9 is a diagram for explaining an optical path of light emitted from the light projecting element in the particle detection sensor according to Embodiment 2 and traveling toward the detection region.
  • 10A is a top view of the particle detection sensor according to Embodiment 3, FIG.
  • FIG. 10B is a front view of the particle detection sensor
  • FIG. 10C is the particle detection sensor
  • FIG. 10D is a bottom view
  • FIG. 10D is a cross-sectional view of the particle detection sensor taken along line AA in FIG.
  • FIG. 11A is a cross-sectional view of the particle detection sensor of Comparative Example 2.
  • FIG. 11B is an enlarged cross-sectional view of a main part of the particle detection sensor showing a state when the inside of the particle detection sensor of Comparative Example 2 shown in FIG. 11A is cleaned.
  • FIG. 12 is a cross-sectional view illustrating a configuration of a particle detection sensor according to Modification 1 of Embodiment 3.
  • FIG. 10B is a front view of the particle detection sensor
  • FIG. 10C is the particle detection sensor.
  • FIG. 10D is a bottom view
  • FIG. 10D is a cross-sectional view of the particle detection sensor taken along line AA in FIG.
  • FIG. 11A is a cross-sectional view of
  • FIG. 13 is a cross-sectional view illustrating a configuration of a particle detection sensor according to Modification 2 of Embodiment 3.
  • FIG. 14 is a cross-sectional view illustrating a configuration of a particle detection sensor according to Modification 3 of Embodiment 3.
  • 15A is a top view of a particle detection sensor according to Modification 4 of Embodiment 3
  • FIG. 15B is a front view of the particle detection sensor
  • FIG. FIG. 15D is a bottom view of the particle detection sensor
  • FIG. 15D is a cross-sectional view of the particle detection sensor taken along line AA in FIG.
  • FIG. 16A is a perspective view illustrating a state when cleaning (maintenance) of the inside of the housing of the particle detection sensor according to the fourth modification of the third embodiment.
  • FIG. 16A is a perspective view illustrating a state when cleaning (maintenance) of the inside of the housing of the particle detection sensor according to the fourth modification of the third embodiment.
  • FIG. 16B is a cross-sectional view illustrating a state when cleaning (maintenance) of the inside of the housing of the particle detection sensor according to Modification 4 of Embodiment 3.
  • FIG. 17 is a cross-sectional view illustrating a schematic configuration of the particle detection sensor according to the first modification.
  • FIG. 18 is a cross-sectional view illustrating a schematic configuration of a particle detection sensor according to another embodiment of the first modification.
  • FIG. 19 is a cross-sectional view illustrating a schematic configuration of a particle detection sensor according to Modification 2.
  • FIG. 20 is a cross-sectional view illustrating a schematic configuration of a particle detection sensor according to Modification 3.
  • FIG. 21 is a cross-sectional view illustrating a schematic configuration of a particle detection sensor according to Modification 4.
  • FIG. 20 is a cross-sectional view illustrating a schematic configuration of a particle detection sensor according to Modification 3.
  • FIG. 22 is a cross-sectional view illustrating a schematic configuration of a particle detection sensor according to another embodiment of the fourth modification.
  • FIG. 23 is a cross-sectional view illustrating a schematic configuration of a particle detection sensor according to Modification 5.
  • FIG. 24 is a cross-sectional view illustrating a schematic configuration of a particle detection sensor according to Modification 6.
  • 25A is a top view of the particle detection sensor according to the modified example 7
  • FIG. 25B is a front view of the particle detection sensor
  • FIG. 25C is a bottom surface of the particle detection sensor.
  • FIG. 25D is a cross-sectional view of the particle detection sensor taken along line BB in FIG.
  • FIG. 26 is an external view of a smoke detector including a particle detection sensor.
  • FIG. 27 is an external view of an air cleaner provided with a particle detection sensor.
  • FIG. 28 is an external view of a ventilation fan provided with a particle detection sensor.
  • FIG. 29 is an external view of an air conditioner including a particle detection
  • FIG. 1 is a diagram illustrating a configuration of a particle detection sensor 1 according to Embodiment 1, wherein (a) is a top view, (b) is a front view, (c) is a bottom view, and (d) is (a). It is sectional drawing in the AA of FIG. In the present embodiment, the direction from the air discharge hole 36 to the air introduction hole 35 in FIG. 1D is the vertically downward direction (the direction of gravity).
  • the particle detection sensor 1 is a photoelectric sensor including a light projecting element 10 and a light receiving element 20, and the light from the light projecting element 10 due to particles in a detection region (light diffusion part) DA.
  • the scattered light is received by the light receiving element 20 to detect particles contained in the gas.
  • the particle detection sensor 1 further includes a housing (case) 30, a reflector 40 having a reflecting surface, and a heating device 50 that heats gas.
  • the reflector 40 and the heating device 50 are disposed in the housing 30.
  • the light projecting element 10 is a light source (light emitting unit) that emits light of a predetermined wavelength, and is, for example, a solid light emitting element such as an LED or a semiconductor laser.
  • a light emitting element that emits infrared light, blue light, green light, red light, or ultraviolet light can be used. In this case, you may comprise so that the mixed wave of 2 wavelengths or more may be emitted.
  • the light emission control system of the light projecting element 10 is not particularly limited, and the light emitted from the light projecting element 10 can be continuous light or pulsed light by DC driving. Moreover, the magnitude
  • the light receiving element 20 is a light receiving unit that receives light, and is an element (photodetector) that receives light and converts it into an electric signal, such as a photodiode, a photo IC diode, a phototransistor, or a high electron multiplier. .
  • the light projecting element 10 and the light receiving element 20 are arranged in a housing 30.
  • the housing 30 is configured to hold the light projecting element 10 and the light receiving element 20.
  • the light projecting element 10 and the light receiving element 20 are disposed in the housing 30 so that their optical axes intersect.
  • the forward scattered light can be easily obtained by matching the optical axis of the light projecting element 10 and the optical axis of the light receiving element 20, but the optical axes of the light projecting element 10 and the light receiving element 20 are simply changed. If they are just matched, the light receiving element 20 will receive direct light from the light projecting element 10 in addition to the forward scattered light, and the particle detection accuracy will be reduced.
  • the optical axes of the light projecting element 10 and the light receiving element 20 are crossed.
  • the angle formed by the optical axis of the light projecting element 10 and the optical axis of the light receiving element 20 is 60 degrees (120 degrees).
  • the outer shape of the housing 30 is, for example, a flat rectangular parallelepiped.
  • the housing 30 is composed of two members, a first housing portion 30a (lid portion) and a second housing portion 30b.
  • a plurality of lead wires 11, 21, and 51 are exposed from the second housing portion 30b.
  • the lead wires 11, 21, and 51 are electrically connected to the light projecting element 10, the light receiving element 20, and the heating device 50, respectively.
  • a light projecting region 31 which is a space region in which light from the light projecting element 10 is projected, and scattered light generated when the light from the light projecting device 10 hits particles in the detection region DA is guided to the light receiving device 20.
  • a light receiving region 32 diffuseused light introducing portion
  • a particle flow path 33 that is a space region through which a gas (such as the atmosphere) containing particles flows, and a trap portion 34 are provided.
  • Each of the light projecting area 31, the light receiving area 32, the particle flow path 33 and the trap part 34 is a space area in the housing 30.
  • the light projection area 31 is a spatial area from the light projecting element 10 to the detection area DA.
  • the light receiving area 32 is a spatial area from the detection area DA to the light receiving element 20.
  • each of the light projecting region 31, the light receiving region 32, and the trap portion 34 has a substantially cylindrical shape or a substantially rectangular tube shape that is surrounded by the inner surface (inner wall) of the housing 30.
  • the bottomed cylindrical space region has an opening at a connection portion with the particle channel 33.
  • each of the light projecting region 31, the light receiving region 32, and the trap portion 34 has an opening that opens toward the particle channel 33, and is connected to the particle channel 33 at each opening.
  • each opening of the light projecting area 31, the light receiving area 32, and the trap part 34 opens toward the detection area DA.
  • the particle channel 33 is a region through which air (gas) containing particles flows.
  • the particle flow path 33 is a gas passage region through which the gas introduced into the housing 30 passes, and is a space region surrounded by the inner surface (inner wall) of the housing 30. That is, the particle flow path 33 is a space area including the detection area DA, and the space area in the housing 30 until the air introduced from the air introduction hole 35 is discharged from the air discharge hole 36 through the detection area DA. It is.
  • the particle flow path 33 is a cylindrical space region having a substantially cylindrical shape or a substantially rectangular tube shape, and includes the entire detection region DA.
  • the particle flow path 33 is a straight flow path from the air introduction hole 35 toward the air discharge hole 36, and is connected to the light projecting area 31, the light receiving area 32, and the trap part 34 in the middle of the flow path. .
  • the inner surface (wall surface) of the housing 30 in the light projecting region 31, the light receiving region 32, the particle flow path 33, and the trap part 34 is preferably black in order to absorb stray light.
  • the housing 30 is a black resin molded product, and the exposed part has at least a black surface inside.
  • the inner surface of the housing 30 may be configured to absorb stray light by performing a surface treatment such as embossing.
  • the detection area DA is an aerosol detection area (aerosol measurement unit) that is an area for detecting particles (aerosol) contained in the gas to be measured.
  • the detection area DA is set so as to exist in the particle flow path 33, and in the present embodiment, the light projection area 31 and the light reception area 32 overlap with the particle flow path 33.
  • the detection area DA is an area including an intersection where the optical axis of the light projecting element 10 and the optical axis of the light receiving element 20 intersect.
  • the gas to be measured is guided from the atmosphere introduction hole 35 to the detection area DA through the particle flow path 33.
  • the detection area DA is, for example, ⁇ 2 mm.
  • the trap part 34 reflects that the light that has passed through the detection area DA without hitting the particles in the detection area DA out of the light from the light projecting element 10 is reflected and scattered in the housing 30 and received by the light receiving element 20. It has a structure to prevent.
  • the trap unit 34 has an optical trap structure, and has a light absorption structure that prevents light once entering the trap unit 34 from exiting the trap unit 34.
  • the inner surface of the housing 30 in the trap portion 34 is provided with a plurality of black protrusions for multiple reflection and absorption of light.
  • the trap part 34 may have a labyrinth structure.
  • the trap portion 34 (light trap structure) is provided at a position facing the light projecting element 10. Specifically, the opening of the trap portion 34 faces the opening of the light projecting region 31.
  • the trap portion 34 is provided only at a position facing the light projecting element 10, but may be provided at a position facing both the light projecting element 10 and the light receiving element 20. However, it may be provided only at a position facing the light receiving element 20. However, when the trap portion 34 is provided only at a position facing the light receiving element 20, it is possible to provide a means such as making the trap portion 34 a through hole so that the light that has once entered the trap portion 34 does not return. Good.
  • the housing 30 is provided with an air introduction hole 35 for introducing air into the particle flow path 33 and an air discharge hole (atmospheric discharge hole) 36 for discharging air from the particle flow path 33. Yes.
  • the atmosphere introduction hole 35 is an atmosphere supply port (atmosphere inlet) for supplying a gas such as the atmosphere existing outside the particle detection sensor 1 to the inside of the particle detection sensor 1 (particle flow path 33).
  • 30 is the atmospheric inlet.
  • the air discharge hole 36 is an air exhaust port (atmosphere outlet) for discharging the air inside the particle detection sensor 1 (particle flow path 33) to the outside of the particle detection sensor 1. Is the exit.
  • the air introduction hole 35 is connected to one of the particle flow paths 33, and the air discharge hole 36 is connected to the other of the particle flow paths 33. Thereby, the atmosphere containing the particles (the gas to be measured) is introduced into the casing 30 from the atmosphere introduction hole 35 and flows into the detection area DA through the particle flow path 33, and from the atmosphere discharge hole 36 to the casing 30. Discharged outside.
  • the air introduction hole 35 has a larger opening area than the air discharge hole 36 in order to efficiently introduce and exhaust gas into the housing 30.
  • the light projecting area 31 is provided with a light projecting lens (light emitting lens) 31a.
  • the light projecting lens 31a is disposed in front of the light projecting element 10, and is configured to advance light (projected beam) emitted from the light projecting element 10 toward the detection area DA. That is, the light emitted from the light projecting element 10 reaches the detection area DA via the light projecting lens 31a.
  • the light projection lens 31a is, for example, a transparent resin lens or a glass lens.
  • the light projecting lens 31a may be a collimating lens that collimates the light emitted from the light projecting element 10 toward the detection area DA, or the light that collects the light emitted from the light projecting element 10 on the detection area DA.
  • a lens may be used, a lens that increases the light intensity of the light projecting element 10 in the detection area DA may be used as the light projecting lens 31a.
  • the intensity of the scattered light varies depending on the location in the detection area DA even if the particles have the same particle size.
  • a lens that makes the light intensity distribution of the element 10 uniform in the entire detection area DA may be used.
  • the light of the light projecting element 10 is used as the light projecting area 31. It is preferable to use a lens that directly reaches the detection area DA without being reflected by the wall surface of the housing 30 in FIG.
  • the light projection lens 31a may not be provided.
  • the light emission area 31 is provided with a light emission stop portion 31b.
  • the light emission diaphragm 31b narrows the light of the light projecting element 10 after passing through the light projecting lens 31a to shield unnecessary light and reduce the condensed diameter.
  • the light emission diaphragm 31b is made of resin or the like, and is formed in a predetermined shape on the inner wall of the light projecting region 31.
  • the light emission diaphragm 31b is composed of a plurality of optical diaphragms each having a circular or polygonal opening (slit).
  • the light emission stop portion 31 b (optical stop) is formed so as to protrude from the inner wall of the light projecting region 31.
  • the light emission diaphragm 31b (optical diaphragm) is made of resin or the like, and may be integrally formed with the housing 30 or may be separate from the housing 30.
  • the reflector 40 (reflecting plate) is a reflecting member that reflects scattered light of the light projecting element 10 by particles in the detection area DA and guides the scattered light to the light receiving element 20.
  • the reflector 40 reflects the scattered light of the particles and collects it on the light receiving element 20. More specifically, the reflector 40 reflects the scattered light of the particles toward the light receiving element 20.
  • the reflector 40 is provided in the light receiving region 32 in the present embodiment.
  • the reflector 40 is a condensing mirror provided along the inner surface of the housing 30 in the light receiving region 32, and the inner surface which is a reflecting surface is a curved surface.
  • the inner surface of the reflector 40 is a part of rotation surface of a spheroid. That is, the reflector 40 is an elliptical mirror in which the shape of the inner surface (reflecting surface) forms a part of the spheroid, and the cross-sectional shape of the inner surface of the reflector 40 is a part of the ellipse.
  • the inner surface of the reflector 40 is mainly a smooth surface or a mirror surface having regular reflection characteristics, but is not limited thereto.
  • the reflector 40 has an opening that opens toward the particle channel 33. Specifically, the opening of the reflector 40 opens toward the detection area DA. In the present embodiment, the opening of the reflector 40 substantially coincides with the opening of the light receiving region 32. That is, the reflector 40 is provided up to the vicinity of the opening of the light receiving region 32.
  • the base member itself may be made of a reflective material such as metal so that the surface of the base member itself becomes a reflective surface, or a reflective film that becomes a reflective surface on the surface of a resin or metal base member May be formed.
  • a metal reflection film such as aluminum, gold, silver or copper, a mirror reflection film, a dielectric multilayer film, or the like can be used.
  • the reflective film a film having a low absorptance and a high reflectance is preferable.
  • an MgF film, a SiO 2 film, a SiO film, an AlN film, an alumina film, an enhanced reflection film, or the like is used.
  • the heating device 50 is a heater that heats the atmosphere.
  • the heating device 50 functions as an airflow generation device that generates an airflow for promoting the flow of gas flowing in the particle flow path 33. That is, the atmosphere including particles can be easily introduced into the detection area DA by heating the atmosphere with the heating device 50.
  • the heating device 50 is, for example, a heater resistor that can be obtained at low cost.
  • the heating device 50 is disposed in the particle channel 33. That is, the heating device 50 heats the gas in the particle channel 33.
  • the heating device 50 is disposed in the vicinity of the air introduction hole 35.
  • the heating device 50 is disposed vertically below the detection area DA.
  • the heating device 50 is a heater resistor
  • the heater resistor when a voltage is applied to the heater resistor, the heater resistor generates heat, the atmosphere around the heater resistor is heated, the density is reduced, and the vertical direction is opposite to gravity. Moving. That is, when the gas in the particle channel 33 is heated by the heating device 50, an upward airflow (upward airflow) can be generated.
  • the gas (atmosphere) to be measured can be easily drawn into the housing 30 (particle channel 33). Compared with the case where 50 is not provided, more particles can be taken into the particle detection sensor 1. Therefore, since the number of particles per unit volume in the detection area DA included in the particle flow path 33 can be increased, the sensitivity can be increased.
  • the gas can pass through the particle flow path 33 between the air introduction hole 35 and the air discharge hole 36. That is, even when the heating device 50 is not operating, it is possible to detect particles contained in the gas.
  • FIGS. 2A, 2B, and 2C show the operation of the particle detection sensor 1 when there is no particle in the gas, when there is a particle with a small particle size in the gas, and when there is a particle with a large particle size in the gas, respectively. It is sectional drawing for demonstrating.
  • the size (particle size) of the particle can be determined based on the size of the signal received by the light receiving element 20, that is, the light intensity of the scattered light from the particle.
  • each output of the signal detected by the light receiving element 20 that is, each peak of the light intensity of the scattered light by the particles corresponds to each of the particles, so that the particle detection sensor 1.
  • the number (amount) of particles in the gas introduced into the gas can also be calculated.
  • FIG. 3 is a cross-sectional view of the particle detection sensor 100 of Comparative Example 1
  • FIG. 4 is a cross-sectional view of the particle detection sensor 1 according to the first embodiment.
  • the light receiving region 32 is not provided with a reflector, and a light receiving lens (condensing lens) 140 is provided.
  • a light receiving lens condensing lens
  • restrictions by the light receiving lens 140 increase, and for example, it is necessary to make the optical axis of the light receiving lens 140 coincide with the optical axis of the light receiving element 20.
  • the shape of the light receiving lens 140 has a small degree of freedom that can be changed due to its function, and is, for example, symmetrical with respect to the lens optical axis. For these reasons, as shown in FIG. 3, when the light receiving lens 140 is used, the expected angle to the light receiving lens 140 with reference to the detection area DA is reduced.
  • the light collected by the lens cannot take light of 180 ° or more, and it cannot take scattered light from various directions. Furthermore, since the focal point of the lens is the detection area DA, the detection area DA is small.
  • the light receiving sensitivity of the scattered light is low.
  • particles having a small particle diameter such as PM2.5 (microparticulate matter) are also present in the particles floating in the gas.
  • the particle detection sensor is required to have an accuracy capable of detecting particles having a particle size of 0.3 ⁇ m or less, for example.
  • a fan may be provided. That is, it is conceivable to improve the detection accuracy of fine particles having a small particle size by increasing the amount of particles entering the particle detection sensor per unit time by increasing the flow of particles by a fan.
  • a heating device such as a heater resistor that is low-cost and space-saving.
  • the particle detection sensor 1 in the present embodiment includes a reflector 40 for reflecting scattered light from particles in the detection area DA and guiding the scattered light to the light receiving element 20 as shown in FIG. Have.
  • the reflector 40 has a greater degree of design freedom than the lens, and thus can be shaped so that more scattered light can be guided to the light receiving element 20.
  • the opening of the reflector 40 can be extended to the limit of the opening of the light receiving region 32, and the expected angle to the reflector 40 based on the detection region DA can be increased. .
  • the shape of the reflector 40 can be determined without making the prospective angle symmetric with respect to the optical axis of the reflector 40 (the optical axis of the light receiving element 20), the shape of the reflector 40 can be freely changed. Can do.
  • the solid angle for collecting scattered light can be increased as compared with the comparative example 1 shown in FIG. 3, so that the light receiving sensitivity of the scattered light can be increased.
  • the detection area DA can be enlarged.
  • the particles easily pass through the detection area DA.
  • the probability of particles passing through the detection area DA is small in Comparative Example 1 shown in FIG. 3, but in the present embodiment shown in FIG. Probability is greatly improved, and light receiving sensitivity is also increased. Therefore, fine particles having a small particle diameter can be detected with high accuracy.
  • grain detection sensor 1 which concerns on this Embodiment is provided with the reflector 40, compared with the case where a lens is provided in the light reception area
  • a highly accurate particle detection sensor can be realized while being low-cost and small.
  • the inner surface of the reflector 40 forms a part of the rotational surface of the spheroid. Therefore, most of the scattered light generated by the particles in the detection area DA can be incident on the light receiving element 20, so that the sensitivity can be further increased.
  • FIG. 5 is a diagram for explaining the positional relationship among the reflector 40, the light receiving element 20, and the detection area DA in the particle detection sensor 1 according to the first embodiment.
  • the reflector 40 in the present embodiment has an inner surface that forms part of the rotational surface of the spheroid, and the cross-sectional shape of the inner surface of the reflector 40 is part of the ellipse. Yes.
  • the reflector 40 is arranged such that one of the two focal points F1 and F2 (first focal point) in the ellipse constituting the spheroid exists in the detection area DA.
  • the light receiving element 20 is disposed in the vicinity of the other focal point F2 (second focal point) of the ellipse.
  • the scattered light generated by the particles in the detection area DA can be incident on the light receiving element 20 with a small number of reflections (one or several times). That is, attenuation of light due to multiple reflection can be avoided. Therefore, since the light receiving efficiency in the light receiving element 20 can be increased, the sensitivity can be further increased.
  • the light receiving efficiency of the light receiving element 20 can be increased, a small detector or the like can be used as the light receiving element 20. That is, it is not necessary to use a photodetector having a particularly large light receiving surface as the light receiving element 20.
  • a heater system that introduces the atmosphere by heating the heater is employed, so that a simple and low-cost sensor can be realized.
  • FIG. 6A and 6B are diagrams showing the configuration of the particle detection sensor 2 according to Embodiment 2, wherein FIG. 6A is a top view, FIG. 6B is a front view, FIG. 6C is a bottom view, and FIG. It is sectional drawing in the AA of FIG. Also in this embodiment, the direction from the air discharge hole 36 to the air introduction hole 35 in FIG.
  • the particle detection sensor 2 in the present embodiment is a photoelectric sensor that includes a light projecting element 10 and a light receiving element 20 in the same manner as the particle detection sensor 1 in the first embodiment.
  • the light contained in the atmosphere is detected by receiving the scattered light of the light from the light projecting element 10 by the particles in the region (light scattering part) DA by the light receiving element 20.
  • the particle detection sensor 2 further includes a housing 30, and a reflector 40, a heating device 50, a first light shielding body 61, a second light shielding body 62, and a light projection diaphragm disposed in the housing 30.
  • the optical axes of the light projecting element 10 and the light receiving element 20 are crossed.
  • the angle formed by the optical axis of the light projecting element 10 and the optical axis of the light receiving element 20. Is 120 degrees (60 degrees).
  • the housing 30 includes a light projecting region 31, a light receiving region 32, a particle channel 33, a light projecting trap unit 34a (first trap unit), and a light receiving trap unit 34b (second trap). Part).
  • Each of the light projecting area 31, the light receiving area 32, the particle flow path 33, the light projecting trap section 34a, and the light receiving trap section 34b is a space area surrounded by the inner surface (inner wall) of the housing 30. 33 has an opening at the connection portion. Each opening part of the light projection area
  • the inner surface (wall surface) of the housing 30 in the light projecting region 31, the light receiving region 32, the particle flow path 33, the light projecting trap unit 34a, and the light receiving trap unit 34b may be black in order to absorb stray light.
  • the inner surface of the housing 30 can be made a black surface by making the housing 30 a black resin molded product.
  • the light projection area 31 is provided with a light projection diaphragm section (light emission diaphragm section) 71.
  • the light projection aperture 71 (first aperture) narrows the light after passing through the light projection lens 31a to shield unnecessary light and reduce the light collection diameter. By providing the light projection aperture 71, stray light can be prevented, and the particle detection accuracy can be improved.
  • the light projection aperture 71 is composed of a plurality of optical apertures each having a circular or polygonal opening (slit).
  • the light projection diaphragm 71 (optical diaphragm) is formed so as to protrude from the inner wall of the light projection area 31.
  • the light projection aperture 71 (optical aperture) is made of resin or the like, and may be integrally formed with the housing 30 or may be separate from the housing 30.
  • an end (end surface) of the aperture of the optical diaphragm in the light projection diaphragm 71 forms an acute angle with two straight lines in a cross section including the optical axis of the optical diaphragm, and includes a surface including one of the two straight lines ( Flat surface or curved surface) is a reflecting surface that reflects incident light in a direction other than the detection area DA.
  • the light projecting trap unit 34a and the light receiving trap unit 34b have an optical trap structure, and light that has once entered the light projecting trap unit 34a and the light receiving trap unit 34b is transmitted from the light projecting trap unit 34a and the light receiving trap unit 34b. It has a light absorption structure that does not go out.
  • the light projecting trap unit 34a and the light receiving trap unit 34b for example, absorb and multi-reflect light that has entered the light projecting trap unit 34a and the light receiving trap unit 34b. By providing the light projecting trap part 34a and the light receiving trap part 34b, stray light in the housing 30 can be absorbed. Thereby, the detection accuracy of particles can be improved.
  • the light projecting trap part 34a and the light receiving trap part 34b may have a labyrinth structure.
  • the light projecting trap part 34a receives and reflects and scatters light that has passed through the detection area DA without hitting the particles in the detection area DA out of the light emitted from the light projecting element 10. It has a structure that prevents the element 20 from receiving light.
  • the light projecting trap part 34a is provided at a position facing the light projecting element 10 across the detection area DA.
  • the projection trap part 34a is provided with a projection opposite diaphragm part 72 (second diaphragm part). That is, the light projection opposite diaphragm portion 72 is provided on the opposite side of the light projecting element 10 with the detection area DA interposed therebetween. By providing the light projection opposite stop portion 72, stray light can be prevented and particle detection accuracy can be improved.
  • the light projection opposite stop 72 includes a plurality of optical stops each having an opening (slit) such as a circle or a polygon.
  • the light projection opposite diaphragm portion 72 (optical diaphragm) is formed so as to protrude from the inner wall of the light projection trap portion 34a.
  • the light projection opposite diaphragm portion 72 (optical diaphragm) is made of resin or the like, and may be integrally formed with the housing 30 or may be separate from the housing 30.
  • the end (end face) of the aperture of the optical stop in the light projection opposite stop portion 72 forms an acute angle by two planes, and one surface of the two planes transmits incident light other than the detection area DA. It is a reflective surface that reflects in the direction. That is, the end (end surface) of the aperture of the optical aperture in the light projection opposite aperture section 72 forms an acute angle with two straight lines in a cross section including the optical axis of the optical aperture, and includes one of the two straight lines. (Plane or curved surface) is a reflecting surface that reflects incident light in a direction other than the detection area DA. Thereby, since stray light can be prevented, the detection accuracy of particles can be improved.
  • a curved surface that guides light to the side opposite to the detection area DA side is formed on the back side of the light projection opposite diaphragm portion 72 in the light projection trap portion 34a.
  • the light receiving trap part 34b reflects and scatters the light traveling on the opposite side to the light receiving element 20 (light receiving area 32) among the scattered light of the particles in the detection area DA and receives it by the light receiving element 20. It has a structure which prevents it being done.
  • the light receiving trap part 34b is provided at a position facing the light receiving element 20 across the detection area DA.
  • the light receiving trap portion 34b is provided with a light receiving opposite stop portion 73 (third stop portion).
  • the light receiving opposite diaphragm portion 73 is provided on the opposite side of the light receiving element 20 with the detection area DA interposed therebetween.
  • the light reception counter diaphragm section 73 is composed of a plurality of optical diaphragms each having an opening (slit) such as a circle or a polygon.
  • the light receiving opposite stop portion 73 (optical stop) is formed so as to protrude from the inner wall of the light receiving trap portion 34b.
  • the light receiving opposite diaphragm 73 (optical diaphragm) is made of resin or the like, and may be integrally formed with the housing 30 or may be separate from the housing 30.
  • the end (end surface) of the aperture of the optical diaphragm in the opposite light receiving diaphragm 73 forms an acute angle with two straight lines in a cross section including the optical axis of the optical diaphragm, and includes a surface including one of the two straight lines (
  • a curved surface or a flat surface is a reflecting surface that reflects incident light in a direction other than the detection area DA.
  • a curved surface that guides light to the side opposite to the detection area DA side is formed on the back side of the light receiving opposite diaphragm portion 73 in the light receiving trap portion 34b.
  • the reflector 40 is disposed in the light receiving region 32.
  • the scattered light of the particles in the detection area DA is guided to the light receiving element 20 by the reflector 40.
  • the end of the reflector 40 on the opening side is in contact with the first protective plate 81.
  • FIG. 7 is a diagram showing a positional relationship among the reflector 40, the light projecting element 10, the light receiving element 20, and the detection area DA in the particle detection sensor 2 according to the second embodiment.
  • the reflector 40 in the present embodiment is also an elliptical mirror, and is constituted by a spheroid.
  • the reflector 40 has one focal point F1 (first focal point) of the two focal points F1 and F2 in the ellipse constituting the spheroid in the detection area DA.
  • the other focal point F2 (second focal point) is arranged in the vicinity of the light receiving element 20. That is, the light receiving element 20 is disposed in the vicinity of the focal point F2 in the ellipse.
  • the focal point F1 correspond to the detection area DA and the focal point F2 correspond to the light receiving element 20
  • the scattered light generated by the particles in the detection area DA is received with a small number of reflections (one or several times).
  • the light can enter the element 20. That is, attenuation of light due to multiple reflection can be avoided. Therefore, the light receiving efficiency in the light receiving element 20 can be increased.
  • the light from the light projection element 10 may be condensed on the focus F1 by the light projection lens 31a. That is, the condensing point of the light emitted from the light projecting lens 31a coincides with the focal point F1.
  • the focal point of the light projection lens 31a may be made coincident with the focal point F1 of the reflector 40 (elliptical mirror).
  • the light projecting lens 31a is a collimating lens, the light emitted from the light projecting lens 31a may be condensed at the focal point F1 by the light projecting diaphragm 71.
  • the condensing point of the light emitted from the light projecting lens 31a coincide with the elliptical focus F1 of the reflector 40, the light density can be increased, and the scattered light of the particles in the detection area DA. Becomes larger. Therefore, the particle detection accuracy can be improved.
  • the second protective plate 82 is disposed between the detection area DA and the light receiving element 20, the focus of the reflector 40 is taken into consideration in consideration of the refractive index of the second protective plate 82.
  • the detection area DA and the light receiving element 20 may be disposed at the positions.
  • the heating device 50 is disposed between the first light shield 61 and the air introduction hole 35 and is disposed so as to cover the air introduction hole 35. ing.
  • the air introduction hole 35, the heating device 50, the first light shield 61, the detection area DA, the second light shield 62, and the air discharge hole 36 are arranged so as to exist on the same straight line. Yes.
  • the first light shielding body 61 and the second light shielding body 62 shield at least one of light emitted from the heating device 50 (heater light) and light entering from the outside of the particle detection sensor 2 (external light).
  • the light heater light emitted from the heating device 50 includes visible light and infrared light.
  • the first light shielding body 61 and the second light shielding body 62 are integrally formed with the housing 30 using the same material as the housing 30, but may be separate from the housing 30.
  • FIG. 8A is an enlarged cross-sectional view showing the configuration around the first light shield 61 in the particle detection sensor 2 according to Embodiment 2
  • FIG. 8B shows the configuration around the second light shield 62 in the particle detection sensor 2. It is an expanded sectional view shown.
  • the first light shield 61 is a heater light shield that shields the heater light, and is disposed between the heating device 50 and the detection area DA.
  • the first light shield 61 in the present embodiment is also an entrance outside light shield that shields light (external light) that enters the inside of the particle detection sensor 2 from the outside through the atmosphere introduction hole 35.
  • the first light shield 61 is constituted by a first light shield wall 61a and a second light shield wall 61b.
  • the first light shielding wall 61a and the second light shielding wall 61b are arranged side by side in the direction from the heating device 50 toward the detection area DA.
  • the detection accuracy of the particles can be improved by shielding the heater light and the outside light.
  • the first light shielding wall 61a is arranged to face the heating device 50.
  • the second light shielding wall 61b is formed in a substantially box shape so as to surround the first light shielding wall 61a and the side portion of the heating device 50 and to cover a part of the surface of the first light shielding wall 61a on the detection area DA side.
  • the second light shielding wall 61b has an opening provided at a position facing the detection area DA.
  • the first light shielding wall 61a is provided so as to cover the opening of the second light shielding wall 61b.
  • the first light shielding wall 61a and the second light shielding wall 61b are provided so that the air introduced into the particle detection sensor 2 can be guided to the detection area DA.
  • the particles introduced into the housing 30 from the air introduction hole 35 are caused to flow on both sides of the heating device 50 and the first light shield wall 61a and the second light shield wall 61b. It goes to the detection area DA through the opening of the second light shielding wall 61b through the space between the inner surface and the two. That is, the particle flow path 33 in the first light shielding body 61 is once branched into two near the inlet of the air introduction hole 35 and merged again into one on the surface of the first light shielding wall 61a on the detection area DA side. It has become. Thereby, the atmosphere introduced into the particle detection sensor 2 can be properly guided to the detection area DA while suppressing the heater light and the outside light from entering the detection area DA.
  • the second light blocking body 62 is an outlet that blocks light (external light) that enters the particle detection sensor 2 from the outside through the air discharge hole 36. It is an external light shield. Thus, by blocking external light, the particle detection accuracy can be improved.
  • the second light shielding body 62 has a plurality of shielding walls arranged side by side in the direction from the detection area DA toward the air discharge hole 36.
  • the plurality of shields are configured so that the air inside the particle detection sensor 2 can be discharged from the air discharge hole 36.
  • the second light shield 62 in the present embodiment is configured by a first light shield wall 62a, a second light shield wall 62b, and a third light shield wall 62c.
  • the first light shielding wall 62 a is disposed so as to face the air discharge hole 36 and cover the air discharge hole 36.
  • the second light shielding wall 62b is formed so as to surround the side portion of the first light shielding wall 62a.
  • the third light shielding wall 62 c is a side wall of the reflector 40.
  • the third light shielding wall 62c is a side wall of the light receiving region 32 where the reflector 40 is disposed.
  • the first light shielding wall 62a, the second light shielding wall 62b, and the third light shielding wall 62c are configured so that the air inside the particle detection sensor 2 can be discharged from the air discharge hole 36.
  • the atmosphere can be exhausted from the particle detection sensor 2 while suppressing stray light and external light from entering the detection area DA.
  • the scattered light from the particles in the detection area DA has reached the first light shield 61 and the second light shield 62.
  • the scattered light is prevented from being reflected on the detection area DA.
  • the first light shield 61 and the second light shield 62 have reflection surfaces that reflect the scattered light of the particles in the detection area DA in directions other than the detection area DA.
  • the surface of the first light shielding wall 61a on the detection area DA side guides the scattered light to the air introduction hole 35 when the scattered light from the detection area DA is incident. It has become a shape.
  • the surface on the detection area DA side of the first light shielding wall 61a is a reflection surface that reflects the scattered light so as to guide it to the air introduction hole 35.
  • the detection area DA It is a curved surface which forms a convex shape toward. That is, the surface of the first light shielding wall 61a on the detection area DA side has a shape that gradually falls vertically downward from the portion (center) facing the second light shielding wall 61b in all directions. Thereby, since stray light can be prevented from entering the detection area DA, the particle detection accuracy can be further improved.
  • the surface of the first light shielding wall 61a on the heating device 50 side (in this embodiment, also the surface of the first light shielding wall 61a on the air introduction hole 35 side) is the heater light from the heating device 50 and the air introduction hole.
  • the external light entering the inside of the housing 30 via the 35 is guided to the air introduction hole 35.
  • the surface on the heating device 50 side of the first light shielding wall 61a is a reflective surface that reflects the heater light and the outside light so as to guide the air to the atmosphere introduction hole 35. It is a curved surface that forms a convex shape. That is, the surface of the first light shielding wall 61a on the heating device 50 side has a shape that gradually falls downward vertically from the center in all directions. Thereby, since unnecessary light can enter the detection area DA, the particle detection accuracy can be further improved.
  • the surface on the detection area DA side of the first light shielding wall 62a has a shape that guides the scattered light to the air discharge hole 36 when the scattered light from the detection area DA is incident. ing.
  • the surface on the detection area DA side of the first light shielding wall 62a is a reflection surface that reflects the scattered light so as to guide it to the air discharge hole 36.
  • the detection area DA It is a curved surface which forms a convex shape toward. That is, the surface of the first light shielding wall 62a on the detection area DA side has a shape that gradually rises vertically upward from the center in all directions. Thereby, since stray light can be prevented from entering the detection area DA, the particle detection accuracy can be further improved.
  • the surface of the first light shielding wall 62a on the atmosphere discharge hole 36 side has a shape that guides external light entering the inside of the housing 30 through the atmosphere discharge hole 36 to the atmosphere discharge hole 36.
  • the surface on the atmosphere discharge hole 36 side of the first light shielding wall 62a is a reflection surface that reflects external light so as to guide it to the atmosphere discharge hole 36, and in the present embodiment, toward the detection area DA. It is a curved surface having a convex shape. That is, the surface of the first light shielding wall 62a on the atmosphere exhaust hole 36 side has a shape that gradually rises vertically upward from the center in all directions. Thereby, since unnecessary light can enter the detection area DA, the particle detection accuracy can be further improved.
  • the first protective plate 81 is a protective member for preventing particles from entering the light projecting region 31.
  • the second protective plate 82 is a protective member for preventing particles from entering the light receiving region 32.
  • Each of the first protective plate 81 and the second protective plate 82 is formed in the housing 30 while particles floating in the atmosphere (dust, pollen, smoke, PM2.5, etc.) are in operation and non-operation of the particle detection sensor 2. When entering, the particles are prevented from entering each of the light projecting region 31 and the light receiving region 32.
  • the first protective plate 81 is disposed so as to cover an opening (an opening of the light projecting region 31) that becomes a connection portion with the particle flow path 33 in the light projecting region 31.
  • the second protective plate 82 is disposed so as to cover an opening (an opening of the light receiving region 32) serving as a connection portion between the light receiving region 32 and the particle flow path 33. More specifically, the second protective plate 82 covers the opening end surface of the reflector 40.
  • the first protective plate 81 and the second protective plate 82 are flat transparent plates having a uniform thickness, and are made of, for example, glass or a transparent resin such as polycarbonate or acrylic.
  • the first protective plate 81 and the second protective plate 82 are transparent plates having a refractive index of 1.5 or less and a thickness of 200 ⁇ m or less.
  • the total transmittance of the first protective plate 81 and the second protective plate 82 is, for example, 99% or more if the Fresnel reflection is ignored.
  • the surface of the second protective plate 82 is preferably a smooth surface so that the scattered light of the particles is not scattered on the surface of the second protective plate 82. Thereby, the position shift of the optical path of the scattered light by the 2nd protection board 82 can be made small.
  • the particle detection sensor 2 in the present embodiment configured as described above detects particles by the same operation as the particle detection sensor 1 in the first embodiment. Can do.
  • the particle detection sensor 2 in the present embodiment includes the reflector 40 as in the particle detection sensor 1 in the first embodiment.
  • the light receiving sensitivity can be increased as compared with the case where a lens is provided in the light receiving region 32. Therefore, even in a heating type particle detection sensor using the heating device 50, not only can the particle contained in the gas be dust, pollen, or smoke, but also PM2.5. Even fine particles having a small particle diameter such as (microparticulate matter) can be distinguished. Thus, even with the particle detection sensor 2 according to the present embodiment, a highly accurate particle detection sensor can be realized while being low-cost and small.
  • the particle detection sensor 2 in the present embodiment includes a light shielding body that shields at least one of the heater light emitted from the heating device 50 and the external light entering the inside from the outside of the particle detection sensor 1.
  • the light shielding body has a shape that suppresses reflection of the scattered light to the detection area DA when the scattered light of the particles in the detection area DA reaches the light shielding body.
  • the particle detection sensor 2 includes a first light shield 61 that shields heater light emitted from the heating device 50 (heater) and external light entering the particle detection sensor 2 from the air introduction hole 35;
  • a second light shielding body 62 that shields external light entering the inside of the particle detection sensor 2 from the air discharge hole 36 is provided.
  • first light shielding body 61 and the second light shielding body 62 have a shape that suppresses the scattered light of the particles in the detection area DA from being reflected by the first light shielding body 61 and the second light shielding body 62 toward the detection area DA. It has become.
  • the scattered light from the detection area DA when the scattered light from the detection area DA is incident on the surface on the detection area DA side of the first light shielding body 61 (first light shielding wall 61a), the scattered light enters the air introduction hole 35. It has a shape that leads.
  • the surface on the detection area DA side of the first light shield 61 (first light shield wall 61 a) is a reflective surface that reflects the scattered light so as to guide it to the air introduction hole 35.
  • the surface of the second light shielding body 62 (first light shielding wall 62a) on the detection area DA side has a shape that guides the scattered light to the air introduction hole 35 when the scattered light from the detection area DA is incident. It has become.
  • the surface on the detection area DA side of the second light shielding body 62 (first light shielding wall 62 a) is a reflecting surface that reflects the scattered light so as to guide it to the air discharge hole 36.
  • the surface on the heating device 50 side (the surface on the atmosphere introduction hole 35 side) of the first light shielding body 61 (first light shielding wall 61a) guides the heater light and the external light to the atmosphere introduction hole 35. It has a shape like this.
  • the surface on the heating device 50 side of the first light shielding body 61 (first light shielding wall 61 a) is a reflecting surface that reflects the heater light and the external light so as to guide the air to the atmosphere introduction hole 35.
  • the surface of the second light shielding body 62 (first light shielding wall 62 a) on the atmosphere discharge hole 36 side is shaped to guide external light to the atmosphere discharge hole 36.
  • the surface of the second light shielding body 62 (first light shielding wall 62 a) on the atmosphere discharge hole 36 side is a reflection surface that reflects external light so as to guide it to the atmosphere discharge hole 36.
  • the first light shield 61 includes a second light shield wall 61b having an opening facing the detection area DA, and a first light shield wall 61a covering the opening of the second light shield wall 61b.
  • the first light shielding wall 61a and the second light shielding wall 61b are arranged so as to be aligned in the direction from the heating device 50 toward the detection area DA, and the atmosphere introduced into the particle detection sensor 1 is detected in the detection area DA. It is provided so that it can be led to.
  • the atmosphere introduced into the particle detection sensor 1 can be properly guided to the detection area DA while suppressing the heater light and external light from entering the detection area DA.
  • the second light shielding body 62 has a plurality of shielding walls (first light shielding wall 62a, second light shielding wall 62b, 3 light shielding walls 62c), and the plurality of shields are configured so that the air inside the particle detection sensor 1 can be discharged from the air discharge hole 36.
  • the atmosphere can be properly discharged from the particle detection sensor 1 while suppressing external light and stray light from entering the detection area DA.
  • the reflector 40 (light receiving region 32) is provided so as to extend into the particle flow path 33, and the reflector 40 (light receiving region 32). Is present between the air discharge hole 36 and the first light shielding wall 62a of the second light shielding body 62 and the detection area DA. That is, a part of the reflector 40 (light receiving area 32) is positioned vertically above the detection area DA. The opening of the reflector 40 (light receiving region 32) is covered with a second protective plate 82.
  • the atmosphere containing the particles introduced into the particle detection sensor 2 collides with the second protection plate 82 and temporarily stays in the vicinity of the second protection plate 82.
  • the detection area DA is set so as to be positioned in the vicinity of the second protective plate 82, the atmosphere containing particles once stays in the detection area DA. Therefore, even when air containing different particles is introduced, the speed can be made constant in the vicinity of the detection area DA, so that the particle detection accuracy can be further improved.
  • FIG. 5 is a diagram for explaining the optical path.
  • a virtual line 71L that connects the tips of the openings of the plurality of optical apertures in the light projection aperture section 71, and light emitted from the light projecting element 10 and traveling toward the detection area DA.
  • the light line is designed so that the contour line (line) 10L is substantially parallel.
  • the virtual line 71L and the contour line 10L of the light emitted from the light projecting element 10 and refracted by the light projecting lens 31a are substantially parallel.
  • the light emitted from the light projecting element 10 and refracted by the light projecting lens 31a passes through the inside of the virtual space region formed by connecting the tips of the openings of the plurality of optical diaphragms in the light projecting diaphragm section 71, and the detection area. Proceed to DA.
  • the light lines are designed to be substantially parallel.
  • the imaginary line 72L and the outline 10L of the light emitted from the light projecting element 10 and entering the light projecting trap part 34a through the detection area DA are substantially parallel. That is, the light that enters the light projecting trap part 34a so as to be emitted from the light projecting element 10 and once converged in the detection area DA by the light projecting lens 31a and then diverge is a plurality of light in the light projecting opposite aperture part 72.
  • the light passes through the inside of a virtual space region formed by connecting the tips of the openings of the optical diaphragms and enters the depth of the light projection trap part 34a.
  • the plurality of optical stops in the light receiving opposite stop portion 73 may have the same configuration with respect to the scattered light of the particles in the detection area DA.
  • a light outline (line) 10L emitted from the light projecting element 10 toward the detection area DA and a virtual line 40L connecting the end face of the reflector 40 are approximately. Parallel.
  • the sensitivity can be improved, so that the particle detection accuracy can be further improved.
  • FIG. 10A and 10B are diagrams showing the configuration of the particle detection sensor 3 according to Embodiment 3, wherein FIG. 10A is a top view, FIG. 10B is a front view, FIG. 10C is a bottom view, and FIG. It is sectional drawing in the AA of FIG. Also in this embodiment, the direction from the air discharge hole 36 to the air introduction hole 35 in FIG.
  • the particle detection sensor 3 in the present embodiment further includes a first protective plate 91 having translucency with respect to the particle detection sensor 1 in the first embodiment.
  • the first protection plate 91 is disposed in the housing 30. Specifically, the first protective plate 91 is disposed at a connection portion between the particle flow path 33 and the light receiving region 32.
  • the first protective plate 91 is a protective member for preventing particles from entering the light receiving region 32.
  • the first protective plate 91 is used when particles floating in the atmosphere (dust, pollen, smoke, PM2.5, etc.) enter the housing 30 during operation and non-operation of the particle detection sensor 3. The particles are prevented from entering the light receiving region 32.
  • the first protective plate 91 covers an opening (an opening of the light receiving region 32) that is a connection portion with the particle flow path 33 of the light receiving region 32. Is arranged. That is, the first protective plate 91 is disposed so as to cover the light receiving region 32. By covering the opening of the light receiving area 32 with the first protective plate 91, the light receiving area 32 becomes a closed space area and prevents particles such as dust, pollen, and smoke from entering the light receiving area 32 from outside the light receiving area 32. it can.
  • the major axis of the ellipse (the optical axis of the reflector 40) and the light of the light receiving element 20 constituting the reflector 40 composed of the main surface of the first protective plate 91 and the rotation surface of the spheroid.
  • the axis forms a right angle.
  • the normal to the main surface of the first protective plate 91 is parallel to the major axis of the ellipse that constitutes the reflector 40 and the optical axis of the light receiving element 20.
  • the first protective plate 91 configured as described above is, for example, a transparent plate made of glass or a transparent resin such as polycarbonate or acrylic.
  • the total transmittance of the first protective plate 91 is, for example, 99% or more if the Fresnel reflection is ignored.
  • a flat plate having a uniform thickness is used as the first protective plate 91. That is, as the first protective plate 91, a flat plate having a constant thickness in the entire region is used.
  • the first protective plate 91 may not be a flat plate with a uniform thickness.
  • the first protective plate 91 In order to attach the first protective plate 91 to the light receiving region 32, the first protective plate 91 has a thin peripheral portion. Or part of the peripheral edge may be cut out.
  • the shape of the first protective plate 91 in plan view may be a shape that covers the opening of the light receiving region 32.
  • the first protective plate 91 may be a circle.
  • a plate-like transparent plate may be used.
  • the first protective plate 91 is configured not to scatter the scattered light of the particles. That is, the surface of the first protective plate 91 is a smooth surface on both the main surface on the detection area DA side and the main surface on the light receiving element 20 side so that light is not scattered by the first protective plate 91.
  • the first protective plate 91 a flat plate having a refractive index of 1.5 or less and a thickness of 200 ⁇ m or less may be used. Thereby, the position shift of the optical path of the scattered light by the 1st protection board 91 can be made small.
  • the surface of the first protective plate 91 since the adhering matter adhering to the surface of the first protective plate 91 may be removed by rubbing with a cleaning tool such as a cotton swab, the surface of the first protective plate 91 has wear resistance. Good. Therefore, the surface of the first protective plate 91 may be subjected to surface treatment or surface coating treatment for improving wear resistance.
  • the particle detection sensor 3 in the present embodiment configured as described above detects particles by the same operation as the particle detection sensor 1 in the first embodiment. Can do.
  • FIG. 11A is a cross-sectional view of the particle detection sensor 100A of Comparative Example 2
  • FIG. 11B shows the state of cleaning the particle detection sensor 100A of Comparative Example 2 shown in FIG. 11A. It is a principal part expanded sectional view.
  • particles are detected by introducing gas containing particles such as dust, pollen and smoke floating in the atmosphere, so the particles adhere to the inside of the particle detection sensor.
  • the detection accuracy may decrease.
  • detection errors also increase. For example, it may be detected that the particles are present even though the particles should not exist, and an erroneous determination may be made.
  • a particle detection sensor 100A having a structure for removing deposits attached inside is considered.
  • the particle detection sensor 100A of Comparative Example 2 is disposed in the light projecting element 110 and the light receiving element 120, the housing 130 that holds the light projecting element 110 and the light receiving element 120, and the light projecting area 131.
  • the lens 131a and the lens 132a disposed in the light receiving region 132 are provided.
  • region which is an area
  • a cleaning tool 200 such as a cotton swab is introduced from the through-hole 170, and the inner wall of the housing 30 constituting the airflow passage region. Remove deposits that adhere to the surface.
  • the particle detection sensor 100A of Comparative Example 2 since particles enter the light receiving region 132, the particles adhere to the lens 132a as adhering matter. Since the lens 132a collects the scattered light of the particles on the light receiving element 120, if the particles adhere to the lens 132a, the lens function of the lens 132a is affected, the light receiving sensitivity is lowered, and the detection accuracy is lowered.
  • the lens 132a is disposed in a deep part of the light receiving region 132, if particles adhere to the lens 132a, it is difficult to wipe off the deposit with a cleaning tool introduced from the through hole 170 as shown in FIG. 11B. That is, although the deposits in the vicinity of the through-hole 170 can be easily wiped off, it is difficult to wipe off deposits that are present away from the through-hole 170. Furthermore, as shown in FIG. 11B, since the peripheral portion of the light receiving region 132 has an intricate structure and has many corner portions, a blind spot is formed by the corner portions, and it is difficult to wipe off the deposits present around the corner portions. It has become.
  • a reflecting plate (elliptical mirror or the like) having a rotating surface such as a spheroid instead of a lens is disposed in the light receiving region.
  • a through-hole in the housing and introducing the cleaning tool like the particle detection sensor 100A of No. 2 it is difficult to clean the entire inner surface (reflecting surface) of the reflecting plate.
  • a first protective plate 91 having translucency is disposed at a connection portion between the particle flow path 33 and the light receiving region 32. ing.
  • the first protective plate 91 is disposed so as to cover the opening of the light receiving region 32 (the opening serving as a connection portion with the particle channel 33).
  • a reflector 40 is provided between the first protective plate 91 and the light receiving element 20 to reflect the scattered light of the particles and guide the scattered light to the light receiving element 20.
  • the inner surface of the reflector 40 is a part of the rotation surface of the spheroid and is an elliptical mirror.
  • the main surface of the first protective plate 91 is perpendicular to the major axis of the ellipsoid of the spheroid constituting the inner surface of the reflector 40.
  • the scattered light of the particles in the detection area DA can be efficiently transmitted through the first protective plate 91, so that the light receiving sensitivity can be prevented from being lowered by arranging the first protective plate 91.
  • the width of the particle flow path 33 and the width of the detection area DA may be matched.
  • FIG. 12 is a cross-sectional view showing a configuration of a particle detection sensor 3A according to Modification 1 of Embodiment 3.
  • the arrangement of the first protective plate 91 is different between the particle detection sensor 3A in the present modification and the particle detection sensor 3 in the third embodiment.
  • the first protective plate 91 according to the third embodiment is arranged so that its main surface is perpendicular to the major axis of the ellipse that constitutes the reflector 40.
  • the first protective plate 91 in the modified example is disposed so that the normal line of the main surface thereof is inclined with respect to the major axis of the ellipse constituting the reflector 40.
  • the first protective plate 91 is arranged at the connection portion between the particle flow path 33 and the light receiving region 32, similarly to the particle detection sensor 3 in the third embodiment. Therefore, it is possible to suppress the adhesion of particles in the light receiving region 32 both during the operation of the particle detection sensor 3A and during the manufacturing process of the particle detection sensor 3A. Therefore, a decrease in detection accuracy can be suppressed.
  • the first protective plate 91 is disposed so as to cover the opening of the light receiving region 32, it is possible to further suppress the adhesion of particles in the light receiving region 32.
  • the light receiving area 32 by sealing the light receiving area 32 with the first protective plate 91, it is possible to prevent air and moisture from entering the light receiving area 32. Thereby, since corrosion of the reflective surface of the reflector 40 can be prevented, the long-term reliability of the light receiving sensitivity and detection accuracy can be further improved.
  • the normal line of the main surface of the first protective plate 91 is inclined with respect to the major axis of the ellipse that constitutes the spheroid of the reflector 40.
  • the opening part of the reflector 40 can be extended to the limit of the opening part of the light-receiving region 32, a large number of reflection surfaces of the reflector 40 can be obtained, and thus the light-receiving sensitivity of the scattered light of the particles in the reflector 40 is easy. Can be high. Therefore, a particle detection sensor that can detect particles with high sensitivity can be realized.
  • FIG. 13 is a cross-sectional view showing a configuration of a particle detection sensor 3B according to Modification 2 of Embodiment 3.
  • the arrangement of the first protective plate 91 is different between the particle detection sensor 3B in the present modification and the particle detection sensor 3 in the third embodiment.
  • the first protective plate 91 in the third embodiment is disposed only in the connection portion between the particle flow path 33 and the light receiving region 32, whereas the first protective plate 91 in the present modification is a particle It is arranged not only at the connection part between the flow path 33 and the light receiving region 32 but also at the connection part between the particle flow path 33 and the trap part 34. Specifically, the first protective plate 91 in the present modification covers both the opening of the light receiving region 32 and the opening of the trap portion 34.
  • the first protective plate 91 constitutes a part of the particle flow path 33. Specifically, the surface of the first protective plate 91 is a wall surface of the particle channel 33.
  • the first protective plate 91 is disposed at the connection portion between the particle flow path 33 and the light receiving region 32 and at the connection portion between the particle flow path 33 and the light receiving region 32.
  • the reflecting surface of the reflector 40 it is possible to prevent the reflecting surface of the reflector 40 from becoming dirty due to the adhesion of particles, so that the reflectance of the reflecting surface of the reflector 40 does not change, and the long-term reliability of light receiving sensitivity and detection accuracy is improved. Can be made. Moreover, since the reflectance of the trap part 34 does not change by the reflector 40, the direct light from the light projecting element 10 that passes through the detection area DA when hitting the particles is reflected inside the housing 30 and received as stray light. It can also suppress entering into the element 20. FIG. Therefore, the long-term reliability of the light receiving sensitivity and detection accuracy can be further improved.
  • the trap portion 34 is not contaminated by the adhesion of particles, so that the reliability as a sensor is improved and the yield is improved.
  • FIG. 14 is a cross-sectional view illustrating a configuration of a particle detection sensor 3C according to Modification 3 of Embodiment 3.
  • the particle detection sensor 3 ⁇ / b> C in the present modification has a configuration in which a second protection plate 92 is further arranged in the particle detection sensor 3 ⁇ / b> B in the modification 2 described above.
  • the particle detection sensor 3 ⁇ / b> C includes a first protection plate 91 disposed so as to cover the light receiving region 32 and the opening of the trap portion 34, the light projecting region 31, and the particle flow path 33. And a second protection plate 92 disposed in the connection portion.
  • the second protective plate 92 is disposed so as to face the first protective plate 91. That is, the second protection plate 92 and the first protection plate 91 are arranged in parallel.
  • the second protective plate 92 is a protective member for preventing particles from entering the light projecting region 31.
  • the second protective plate 92 is disposed so as to cover an opening (an opening of the light projecting region 31) serving as a connection portion between the light projecting region 31 and the particle flow path 33.
  • the second protective plate 92 is disposed so as to cover the light projecting region 31, and the light projecting region 31 is closed by covering the opening of the light projecting region 31 with the second protective plate 92. It becomes.
  • the second protective plate 92 and the first protective plate 91 constitute a part of the particle flow path 33.
  • the surfaces of the first protective plate 91 and the second protective plate 92 are wall surfaces of the particle flow path 33
  • the particles introduced into the particle flow path 33 are the first protective plate 91 and the second protective plate. Passes between the plates 92.
  • the second protective plate 92 is a transparent plate made of, for example, glass or transparent resin, and the total transmittance is, for example, 99% or more if the Fresnel reflection is ignored. Further, a flat plate having a uniform thickness is used as the second protective plate 92. Note that the second protective plate 92 may not be a flat plate having a uniform thickness. Like the first protective plate 91, the peripheral portion is thin or a part of the peripheral portion is notched for mounting. It may be.
  • the shape of the second protective plate 92 in plan view may be a shape that covers the opening of the light projecting region 31.
  • the second protective plate 92 serves as the second protective plate 92.
  • a disc-shaped transparent plate may be used.
  • the second protective plate 92 is also configured not to scatter the scattered light of the particles. That is, the surface of the second protective plate 92 is a smooth surface on both the main surface on the detection area DA side and the main surface on the light projecting element 10 side so that light is not scattered by the second protective plate 92.
  • the surface of the second protective plate 92 has wear resistance. Good. Therefore, the surface of the second protective plate 92 is preferably subjected to surface treatment or surface coating treatment for improving wear resistance.
  • the first protective plate 91 is disposed at the connection portion between the particle flow path 33 and the light receiving region 32 and at the connection portion between the particle flow path 33 and the light receiving region 32. Therefore, the same effect as that of the second modification of the third embodiment can be obtained.
  • a second protective plate 92 is disposed at the connection portion between the light projecting region 31 and the particle flow path 33.
  • the light projection lens 31a can be arrange
  • the space formed by the first protective plate 91 and the second protective plate 92 may form a part of the particle flow path 33 and coincide with the width of the detection area DA.
  • the space between the first protective plate 91 and the second protective plate 92 is configured to be a part of the particle flow path 33, and the distance between the first protective plate 91 and the second protective plate 92 is set.
  • the width of the particle flow path 33 is preferably matched with the width of the detection area DA.
  • FIG. 15 is a cross-sectional view illustrating a configuration of a particle detection sensor 3D according to Modification 4 of Embodiment 3, where (a) is a top view, (b) is a front view, (c) is a bottom view, and (d). ) Is a sectional view taken along line AA in FIG.
  • the particle detection sensor 3D in the present modification is the same as the particle detection sensor 3C in the third modification of the third embodiment, and the housing 30 further includes the first protection plate 91 and the first protection plate 91. 2 It has the cleaning tool introduction hole 37 into which the cleaning tool for removing the deposit
  • the cleaning tool introduction hole 37 is a through hole provided in the first housing portion 30a.
  • the cleaning tool introduction hole 37 is configured such that the cleaning tool can be inserted from the horizontal direction of the main surfaces of the first protection plate 91 and the second protection plate 92.
  • the cleaning tool introduction hole 37 is provided so as to open the main surface horizontal direction of the first protective plate 91 and the second protective plate 92, and more specifically, the first housing portion 30a.
  • the first protection plate 91 and the second protection plate 92 are provided so as to open portions facing each other. That is, the cleaning tool introduction hole 37 opens a part of the particle flow path 33.
  • the cleaning tool introduction hole 37 is provided in a long shape along the direction in which the air flows in the particle flow path 33 (flow path direction).
  • the cleaning tool introduction hole 37 is blocked by the lid 38.
  • the lid 38 is detachably fitted in the cleaning tool introduction hole 37. Therefore, when cleaning the inside of the housing 30 such as the first protection plate 91 and the second protection plate 92, the lid 38 is removed to open the cleaning tool introduction hole 37, and a cleaning tool such as a cotton swab is removed from the cleaning tool introduction hole 37. Insert and clean the inside of the housing 30.
  • the particle detection sensor 3 ⁇ / b> D by using the cleaning tool introduction hole 37, it is possible to perform maintenance for removing adhered substances such as particles adhered in the housing 30. For example, deposits attached to the surfaces of the first protection plate 91 and the second protection plate 92, the wall surface of the particle flow path 33, or other wall surfaces in the housing 30 can be removed.
  • FIGS. 16A and 16B show a state when the inside of the housing of the particle detection sensor 3D according to the present modification is cleaned (maintenance).
  • the cleaning tool introduction hole 37 is provided at a position facing the first protection plate 91 and the second protection plate 92, so that it is inserted from the cleaning tool introduction hole 37.
  • the cleaning tool 200 can easily remove deposits attached to the surfaces of the first protection plate 91 and the second protection plate 92.
  • the cleaning tool introduction hole 37 is configured so that the cleaning tool 200 can be inserted from the horizontal direction of the main surface of the first protection plate 91 and the second protection plate 92. Accordingly, when the cleaning tool 200 such as a cotton swab is inserted into the cleaning tool introduction hole 37, the cleaning tool 200 can be inserted from the horizontal direction of the main surfaces of the first protection plate 91 and the second protection plate 92.
  • the cleaning tool 200 is rubbed against the surfaces of the first protection plate 91 and the second protection plate 92 by the cleaning tool 200 inserted into the cleaning tool introduction hole 37.
  • the cleaning tool 200 By moving the cleaning tool 200 back and forth along the direction perpendicular to the insertion direction of the cleaning tool 200, the deposits on the surfaces of the first protection plate 91 and the second protection plate 92 can be wiped off.
  • the moving direction of the cleaning tool 200 when scraping off the deposits on the first protection plate 91 and the second protection plate 92 is not limited to the direction perpendicular to the insertion direction of the cleaning tool 200. It may be a direction or the like.
  • the cleaning tool introduction hole 37 is provided at a position where the main surface horizontal direction of the first protection plate 91 and the second protection plate 92 is opened. Thereby, the cleaning tool 200 can be easily inserted into the housing 30 from the horizontal direction of the main surfaces of the first protection plate 91 and the second protection plate 92 via the cleaning tool introduction hole 37.
  • the cleaning tool introduction hole 37 is provided in a long shape along the direction in which the air flows in the particle flow path 33.
  • the cleaning tool 200 inserted into the cleaning tool introduction hole 37 is moved back and forth along the flow path direction of the particle flow path 33, thereby adhering substances on the main surfaces of the first protection plate 91 and the second protection plate 92. Can be easily wiped off.
  • the cleaning tool introduction hole 37 is closed by a lid 38 that is detachably attached to the cleaning tool introduction hole 37.
  • this modification can also be applied to the third embodiment and its modifications 1 to 3.
  • the cleaning tool 200 is inserted into the cleaning tool introduction hole 37 in order to remove deposits attached to the surface of the first protective plate 91.
  • FIG. 17 is a cross-sectional view illustrating a schematic configuration of a particle detection sensor 1A according to the first modification.
  • the particle detection sensor 1A according to the present modification is similar to the particle detection sensor 1 according to the first embodiment, in which the light projecting element 10, the light projecting lens 31a, the light receiving element 20, the reflector 40A, and the heating are performed. And a device (not shown).
  • the light receiving element 20 receives the scattered light of the light of the light projecting element 10 due to the particles in the detection area DA, thereby detecting particles contained in the gas.
  • the reflector 40A in the present modification has an inner surface that forms part of the rotational surface of the spheroid, similar to the reflector 40 in the first embodiment. Further, two through holes 41a and 41b are provided on the side of the reflector 40A.
  • the flow path direction of the particle flow path 33 in which the detection area DA exists is a direction perpendicular to the paper surface, and a heating device such as a heater resistor is installed in the particle flow path 33.
  • the light projecting element 10 and the light projecting lens 31a are arranged so as to face the through hole 41a, and the optical axis of the light projecting element 10 and the light projecting lens 31a and the central axes of the two through holes 41a and 41b are arranged. Match.
  • the light emitted from the light projecting element 10 passes through the through hole 41a and is projected onto the detection area DA set in the inner part of the reflector 40A.
  • light that travels straight without hitting particles out of the light from the light projecting element 10 passes through the through hole 41 b and goes out of the reflector 40 ⁇ / b> A, and therefore does not enter the light receiving element 20.
  • the particle detection sensor 1 ⁇ / b> A includes the reflector 40 ⁇ / b> A that reflects the scattered light of the particles in the detection area DA and guides the scattered light to the light receiving element 20.
  • a heating type particle detection sensor using a heating device can detect particles with a small particle size contained in gas with high accuracy.
  • the reflector 40A uses a portion of the spheroid excluding the portion where the two through holes 41a and 41b and the light receiving element 20 are provided as a reflecting surface.
  • the reflector 40A is arranged so that one focus of the ellipse exists in the detection area DA, and the light receiving element 20 is arranged in the vicinity of the other focus of the ellipse.
  • the scattered light generated by the particles in the detection area DA can be incident on the light receiving element 20 with a small number of reflections, a more accurate particle detection sensor can be realized.
  • the light receiving efficiency can be increased by arranging the light receiving element 20 in the vicinity of the focal point of the ellipse, a small photodetector or the like can be used as the light receiving element 20.
  • the two through holes 41a and 41b are provided so that the central axes of the through holes 41a and 41b are orthogonal to the major axis of the ellipse.
  • the particle detection sensor 1A ′ shown in FIG. As described above, the central axes of the through holes 41a and 41b of the reflector 40A ′ may be provided so as to intersect with the long axis of the ellipse at an angle.
  • FIG. 19 is a cross-sectional view showing a schematic configuration of a particle detection sensor 1B according to Modification 2.
  • the particle detection sensor 1B in the present modification is similar to the particle detection sensor 1 in the first embodiment described above, with the light projecting element 10, the light projecting lens 31a, the light receiving element 20, the reflector 40B, and the heating. And a device (not shown).
  • the light receiving element 20 receives the scattered light of the light of the light projecting element 10 due to the particles in the detection area DA, thereby detecting particles contained in the gas.
  • the reflector 40B in the present modification has an inner surface that forms part of the rotational surface of the spheroid, similar to the reflector 40 in the first embodiment.
  • the reflector 40B is arranged so that one of the focal points of the ellipse exists in the detection area DA, and the light receiving element 20 is arranged in the vicinity of the other focal point of the ellipse.
  • the optical axis of the light projecting element 10, the optical axis of the light receiving element 20, and the rotation axis (optical axis) of the reflector 40B are the same.
  • a through hole 42 is provided at the end of the major axis of the spheroid. The light emitted from the light projecting element 10 passes through the through hole 42 and is projected onto the detection area DA.
  • a shielding plate 60 is disposed between the light projecting element 10 and the light receiving element 20.
  • the shielding plate 60 is a shielding plate configured to absorb or cut light directly incident on the light receiving element 20 from the light projecting element 10.
  • the flow direction of the particle flow path 33 in which the detection area DA is present is the direction perpendicular to the paper surface, and the particle flow path 33 is provided with a heating device such as a heater resistor.
  • the particle detection sensor 1B includes the reflector 40B that reflects the scattered light of the particles in the detection area DA and guides the scattered light to the light receiving element 20.
  • a heating type particle detection sensor using a heating device can detect particles with a small particle size contained in the gas with high accuracy.
  • the reflector 40B uses a portion of the spheroid excluding the portion where the one through hole 42 and the light receiving element 20 are provided as a reflecting surface.
  • the reflector 40B is arranged so that one focus of the ellipse exists in the detection area DA, and the light receiving element 20 is In the vicinity of the other focus of the ellipse.
  • the scattered light generated by the particles in the detection area DA can be incident on the light receiving element 20 with a small number of reflections, a more sensitive particle detection sensor can be realized.
  • the light receiving efficiency can be increased by arranging the light receiving element 20 in the vicinity of the focal point of the ellipse, a small photodetector or the like can be used as the light receiving element 20.
  • FIG. 20 is a cross-sectional view showing a schematic configuration of a particle detection sensor 1C according to Modification 3.
  • the particle detection sensor 1C according to the present modification is similar to the particle detection sensor 1 according to the first embodiment described above, with the light projecting element 10, the light projecting lens 31a, the light receiving element 20, the reflector 40C, and the heating. And a device (not shown).
  • the light receiving element 20 receives the scattered light of the light of the light projecting element 10 due to the particles in the detection area DA, thereby detecting particles contained in the gas.
  • the reflector 40C in the present modification reflects scattered light caused by particles in the detection area DA and guides it to the light receiving element 20.
  • the reflector 40C has a rotating surface of a spheroid. And part of the rotating surface of the parabola.
  • the reflector 40C is arranged so that the parabolic focus F exists in the detection area DA, and the light receiving element 20 is positioned on the side opposite to the apex of the parabola across the parabolic focus F. Is arranged. That is, in the present modification, the optical axis of the light projecting element 10, the optical axis of the light receiving element 20, and the rotation axis (optical axis) of the reflector 40C are the same.
  • the reflector 40C is provided with a through-hole 43 at the top of the rotating parabola.
  • the light emitted from the light projecting element 10 passes through the through hole 43 and is projected onto the detection area DA set in the inner part of the reflector 40C.
  • a shielding plate 60 is disposed between the light projecting element 10 and the light receiving element 20.
  • the flow direction of the particle flow path 33 in which the detection area DA is present is the direction perpendicular to the paper surface, and the particle flow path 33 is provided with a heating device such as a heater resistor.
  • the particle detection sensor 1 ⁇ / b> C in the present modification includes the reflector 40 ⁇ / b> C that reflects the scattered light of the particles in the detection area DA and guides the scattered light to the light receiving element 20.
  • a heating type particle detection sensor using a heating device can detect particles with a small particle size contained in the gas with high accuracy.
  • the inner surface of the reflector 40C forms a part of the rotation surface of the rotating parabola, and the reflector 40 is arranged so that the focal point F of the parabola exists in the detection area DA,
  • the light receiving element 20 is disposed so as to be located on the opposite side of the apex of the parabola across the parabolic focus F.
  • the light from the light projecting element 10 strikes and scatters the particles in the detection area DA, and the scattered light is reflected by the reflector 40C and becomes parallel light. Incident. Accordingly, a large amount of scattered light generated by the particles in the detection area DA can be obtained, and the scattered light can be incident on the light receiving element 20 with a small number of reflections, so that a highly sensitive particle detection sensor can be realized.
  • the scattered light generated by the particles in the detection area DA can be incident on the light receiving element 20 with a small number of reflections, a more sensitive particle detection sensor can be realized.
  • the light receiving surface of the light receiving element 20 is enlarged or the lens that covers the light receiving surface of the light receiving element 20 is enlarged to produce parallel light. It is preferable that most of the light can be received by the light receiving element 20.
  • FIG. 21 is a cross-sectional view illustrating a schematic configuration of a particle detection sensor 1D according to Modification 4.
  • the particle detection sensor 1D in the present modification example is similar to the particle detection sensor 1C in the modification example 3, and the light projecting element 10, the light projecting lens 31a, the light receiving element 20, the reflector 40D, and the heating device ( (Not shown), and the light receiving element 20 receives the scattered light of the light of the light projecting element 10 due to the particles in the detection area DA, thereby detecting particles contained in the gas.
  • the reflector 40D in the present modification reflects light scattered by particles in the detection area DA and guides it to the light receiving element 20, and the inner surface forms part of the rotation surface of the paraboloid as in the third modification. Yes. Further, two through holes 44a and 44b are provided on the side of the reflector 40D.
  • the light projecting element 10 and the light projecting lens 31a are arranged so as to face the through hole 44a, and the optical axis of the light projecting element 10 and the light projecting lens 31a and the central axes of the two through holes 44a and 44b are arranged. Match.
  • the light emitted from the light projecting element 10 passes through the through hole 44a and is projected onto the detection area DA set in the inner part of the reflector 40D. Further, light that travels straight without hitting the particles out of the light from the light projecting element 10 passes through the through hole 44b and goes out of the reflector 40D, and therefore does not enter the light receiving element 20.
  • the reflector 40D is arranged so that the parabolic focus F exists in the detection area DA, and the light receiving element 20 is located on the opposite side of the parabola from the top of the parabola. Is arranged.
  • the flow direction of the particle flow path 33 in which the detection area DA is present is the direction perpendicular to the paper surface, and the particle flow path 33 is provided with a heating device such as a heater resistor.
  • the particle detection sensor 1D includes the reflector 40D that reflects the scattered light of the particles in the detection area DA and guides the scattered light to the light receiving element 20.
  • a heating type particle detection sensor using a heating device can detect particles with a small particle size contained in the gas with high accuracy.
  • the reflector 40D formed of the rotation surface of the rotating parabola is arranged so that the focal point F of the parabola exists in the detection area DA, and the light receiving element 20 is It is arranged so as to be located on the side opposite to the apex of the parabola across the focal point F of the parabola.
  • the scattered light of the particles in the detection area DA is reflected by the reflector 40D and becomes parallel light and enters the light receiving element 20, so that the scattered light generated by the particles in the detection area DA is reduced.
  • a large amount can be obtained, and the scattered light can be incident on the light receiving element 20 with a small number of reflections. Therefore, a highly sensitive particle detection sensor can be realized.
  • the light receiving surface of the light receiving element 20 is increased or the lens covering the light receiving surface of the light receiving element 20 is increased to generate parallel light. It is preferable that most of the light can be received by the light receiving element 20. Or you may arrange
  • FIG. 23 is a cross-sectional view illustrating a schematic configuration of a particle detection sensor 1E according to Modification 5.
  • the particle detection sensor 1E in the present modification is similar to the particle detection sensor 1 in the first embodiment, in which the light projecting element 10, the light receiving element 20, the reflector 40, and a heating device (not shown).
  • the light receiving element 20 receives the scattered light of the light of the light projecting element 10 due to the particles in the detection area DA, thereby detecting the particles contained in the gas.
  • the reflector 40 formed of the rotation surface of the spheroid is arranged so that one focal point of the ellipse exists in the detection area DA, and also receives light.
  • the element 20 is disposed in the vicinity of the other focus of the ellipse.
  • grain detection sensor 1E in this modification is further provided with the auxiliary reflector 40E.
  • the auxiliary reflector 40E reflects the scattered light that does not go to the reflector 40 out of the scattered light from the particles in the detection area DA toward the reflector 40.
  • the auxiliary reflector 40E is, for example, a reflection mirror having a concave curved surface with a predetermined shape.
  • the flow direction of the particle flow path 33 in which the detection area DA is present is the direction perpendicular to the paper surface, and the particle flow path 33 is provided with a heating device such as a heater resistor.
  • the particle detection sensor 1E includes the reflector 40 that reflects the scattered light of the particles in the detection area DA and guides the scattered light to the light receiving element 20 as in the first embodiment. Yes.
  • a heating type particle detection sensor using a heating device can detect particles with a small particle size contained in the gas with high accuracy.
  • the auxiliary reflector 40E since the auxiliary reflector 40E is provided, the scattered light that does not go to the reflector 40 among the scattered light from the particles in the detection area DA can be reflected toward the reflector 40.
  • the reflector 40 is arranged so that one focus of the ellipse exists in the detection area DA, and the light receiving element 20 is In the vicinity of the other focus of the ellipse.
  • the scattered light generated by the particles in the detection area DA can be incident on the light receiving element 20 with a small number of reflections, a more sensitive particle detection sensor can be realized.
  • the light receiving efficiency can be increased by arranging the light receiving element 20 in the vicinity of the focal point of the ellipse, a small photodetector or the like can be used as the light receiving element 20.
  • FIG. 24 is a cross-sectional view illustrating a schematic configuration of a particle detection sensor 1F according to Modification 6.
  • the particle detection sensor 1F is similar to the particle detection sensor 1 according to the first embodiment, and includes a light projecting element 10, a light receiving element 20, a reflector 40F, and a heating device (not shown).
  • the light receiving element 20 receives the scattered light of the light of the light projecting element 10 due to the particles in the detection area DA, thereby detecting the particles contained in the gas.
  • the flow channel direction of the particle flow channel (not shown) in which the detection area DA exists is the direction perpendicular to the paper surface.
  • the reflector 40F in the present modification reflects light scattered by particles in the knowledge area DA and guides it to the light receiving element 20, and is an assembly of a plurality of micromirrors each having a curved surface or a flat surface.
  • the inner surface of the reflector 40F has a shape that forms a part of the rotation surface of a substantially parabolic paraboloid as a whole. That is, instead of a reflector having a smooth curved surface as in the first embodiment, a reflector 40F in which each inner surface is configured by a plurality of minute mirrors having a curved surface or a flat surface may be used.
  • the flow direction of the particle flow path 33 in which the detection area DA is present is the direction perpendicular to the paper surface, and the particle flow path 33 is provided with a heating device such as a heater resistor.
  • the reflector 40F that reflects the scattered light of the particles in the detection area DA and guides the scattered light to the light receiving element 20 is provided as in the first embodiment. Yes.
  • a heating type particle detection sensor using a heating device can detect particles with a small particle size contained in the gas with high accuracy.
  • the inner surface of the reflector 40F forms a part of the rotation surface of the substantially spheroid, and the reflector 40F is arranged so that one focus of the ellipse exists in the detection area DA.
  • the light receiving element 20 is disposed in the vicinity of the other focal point of the ellipse.
  • the scattered light generated by the particles in the detection area DA can be incident on the light receiving element 20 with a small number of reflections, a highly sensitive particle detection sensor can be realized.
  • the light receiving efficiency can be increased by arranging the light receiving element 20 in the vicinity of the focal point of the ellipse, a small photodetector or the like can be used as the light receiving element 20.
  • the flow direction of the particle flow channel 33 (the direction in which the gas to be measured flows) is the vertical direction (vertical direction) on the paper surface, but may be the vertical direction on the paper surface. That is, in the first to third embodiments, the flow path axis of the particle flow path 33 is set to exist on a plane through which each optical axis of the light projecting element 10 and the light receiving element 20 passes, but is orthogonal to the plane. You may set to do.
  • the air introduction hole 35 and the air discharge hole 36 are provided on the upper surface and the bottom surface of the casing 30 in the vertical direction.
  • the present invention is not limited to this.
  • the air introduction hole 35 and the air discharge hole 36 may be provided on the main surface of the housing 30 (the first housing portion 30a in FIG. 25).
  • a light shield 63 may be provided as shown in FIG. Similar to the first light shielding body 61 and the second light shielding body 62, the light shielding body 63 shields at least one of the light from the heating device 50 and the outside light, and the scattered light of the particles in the detection area DA When the light reaches the light shield 63, the scattered light is prevented from being reflected on the detection area DA.
  • the structure of the 1st light shielding body 61 and the 2nd light shielding body 62 can be applied to the light shielding body 63 suitably.
  • the inner surface of the reflector is a part of the surface of the spheroid or parabola, but the present invention is not limited to this. It can be.
  • the conic curve may be selected from an ellipse, a parabola and a hyperbola instead of a circle. That is, the inner surface of the reflector is preferably a part of a spheroid, rotating parabola, or rotating hyperbolic curved surface (rotating surface) rather than a spherical curved surface (spherical surface).
  • the inner surface of the reflector is spherical
  • diffuse reflection is used like an integrating sphere
  • scattered light is reflected (multiple reflection) and attenuated many times, so that light does not enter the light receiving element 20 so much.
  • a sphere only about 1/100 is received compared to the case of a spheroid.
  • a reflector is disposed in the light receiving region 32.
  • a lens may be disposed in the light receiving region 32 instead of the reflector.
  • a condensing lens that collects the scattered light of particles in the detection area DA on the light receiving element 20 may be disposed in the light receiving area 32.
  • the first light shield 61 is configured to shield both the heater light and the outside light, but may be configured to shield only one of them.
  • the first light shield 61 is a heater light shield that shields only the heater light
  • an entrance external light shield that shields the external light from the air introduction hole 35 may be additionally provided.
  • a heater light shield that shields the heater light may be additionally provided.
  • the cleaning tool introduction hole 37 is provided separately from the air introduction hole 35 and the air discharge hole 36 (that is, the cleaning tool introduction hole 37 is a hole dedicated for cleaning).
  • the air introduction hole 35 and the air discharge hole 36 may be used as the cleaning tool introduction hole.
  • a cleaning tool may be inserted from the air introduction hole 35 and the air discharge hole 36 to remove the deposits on the surfaces of the first protection plate 91 and the second protection plate 92.
  • the particle detection sensor in the first to third embodiments can be used for various devices.
  • the particle detection sensor by mounting the particle detection sensor on the dust sensor, it can be realized as a dust sensor including the particle detection sensor.
  • the dust sensor detects dust particles with the built-in particle detection sensor, the dust sensor notifies the detection of dust by sound or light or displays the dust on the display unit.
  • the particle detection sensor in the first to third embodiments can be realized as a smoke detector as shown in FIG. 26 by mounting the particle detection sensor on the smoke detector.
  • the smoke detector detects smoke particles with the built-in particle detection sensor, the smoke detector notifies the detection of smoke by sound or light or displays the smoke on the display unit.
  • the particle detection sensor or the dust sensor in the first to third embodiments is mounted on an air purifier, a ventilation fan, or an air conditioner, so that an air purifier as shown in FIG. 27, a ventilation fan as shown in FIG. It can be realized as an air conditioner as shown in FIG.
  • the air purifier, the ventilation fan, or the air conditioner may detect that dust is detected by the built-in particle detection sensor, and may simply display that the dust is detected on the display unit or activate the fan.
  • the fan may be controlled such as changing the rotation speed.
  • the particle detection sensor 3D including the cleaning tool introduction hole 37 is built in the outer casing of the device.
  • the user can insert the cleaning tool 200 such as a cotton swab into the housing 30 and easily clean the first protective plate 91 and the second protective plate 92 in the cleaning tool introduction hole 37 in the outer casing of the device.
  • a through hole may be provided in the facing portion.
  • the medium containing particles is the atmosphere (air), but the present invention can also be applied to a medium other than the atmosphere (liquid such as water).

Abstract

A particle-detecting sensor (1) that has a light-emitting element (10) and a light-receiving element (20). Light from the light-emitting element (10) that has been scattered by particles in a detection region (DA) is received by the light-receiving element (20) in order to detect particles in a gas. This particle-detecting sensor (1) is provided with a heating device (50) that heats the gas and a reflector (40) that reflects the scattered light so as to guide said scattered light to the light-receiving element (20).

Description

粒子検出センサ、ダストセンサ、煙感知器、空気清浄機、換気扇及びエアコンParticle detection sensor, dust sensor, smoke detector, air cleaner, ventilation fan and air conditioner
　本発明は、粒子検出センサ、及び、粒子検出センサを備えた、ダストセンサ、煙感知器、空気清浄機、換気扇又はエアコン等の機器に関する。より具体的には、大気中に浮遊する粒子（エアロゾル）を当該粒子の散乱光によって検知する光散乱式粒子検出センサ及びこれを用いた空気清浄機等の機器に関する。 The present invention relates to a particle detection sensor and a device having a particle detection sensor, such as a dust sensor, a smoke detector, an air cleaner, a ventilation fan, or an air conditioner. More specifically, the present invention relates to a light-scattering particle detection sensor that detects particles (aerosol) floating in the atmosphere using scattered light of the particles, and an apparatus such as an air purifier using the same.
　光散乱式粒子検出センサは、投光素子と受光素子とを備える光電式センサであり、測定対象の気体を取り込んで投光素子の光を当該気体に照射し、その散乱光によって気体に含まれる粒子の有無を検出するものである。例えば、大気中に浮遊するホコリ・花粉・煙等の粒子を検出することができる。 The light scattering particle detection sensor is a photoelectric sensor including a light projecting element and a light receiving element, takes in a gas to be measured, irradiates the light of the light projecting element, and is contained in the gas by the scattered light. It detects the presence or absence of particles. For example, particles such as dust, pollen, and smoke floating in the atmosphere can be detected.
　この種の光散乱式粒子検出センサとして、迷光の発生を低減するために、投光素子又は受光素子と対向する位置に光トラップが設けられたものが知られている（例えば特許文献１参照）。 As this type of light scattering type particle detection sensor, a sensor provided with a light trap at a position facing a light projecting element or a light receiving element is known in order to reduce the generation of stray light (see, for example, Patent Document 1). .
特開平１１－２４８６２９号公報Japanese Patent Laid-Open No. 11-248629 実開平４－１１３０５８号公報Japanese Utility Model Publication No.4-113058 特開平８－２０１２６３号公報JP-A-8-201263
　近年、より粒径の小さい微粒子を検出するために粒子検出センサのさらなる高精度化が要望されており、例えば、ファンによって気流を発生させて粒子検出センサ内に沢山の粒子を取り込むことで高精度化することが考えられている。 In recent years, there has been a demand for higher accuracy of particle detection sensors in order to detect fine particles with smaller particle diameters. For example, high accuracy can be obtained by generating a stream of air with a fan and capturing many particles in the particle detection sensor. It is considered to become.
　しかしながら、ファンを設けると、粒子検出センサ全体のコストが高くなったり粒子検出センサが大型化したりする。このため、低コストのヒータ抵抗（抵抗加熱）によって気流を発生させることが考えられる。 However, if a fan is provided, the cost of the entire particle detection sensor increases or the particle detection sensor becomes larger. For this reason, it is conceivable to generate an air flow by low-cost heater resistance (resistance heating).
　しかしながら、ヒータ抵抗を用いた方法では、流速が遅く、粒径の小さな微粒子を精度良く検出することができない。 However, the method using the heater resistance has a low flow rate and cannot accurately detect fine particles having a small particle size.
　本発明は、このような課題に鑑みてなされたものであり、ヒータ抵抗等の加熱装置によって気流を発生させる加熱方式であっても、微粒子を高精度で検出できる粒子検出センサ等を提供することを第１の目的とする。 The present invention has been made in view of such problems, and provides a particle detection sensor or the like that can detect fine particles with high accuracy even in a heating method in which an air flow is generated by a heating device such as a heater resistor. Is the first purpose.
　また、光散乱式粒子検出センサでは、ホコリ・花粉・煙等の粒子を含む気体を内部に導入することによって粒子を検出するため、当該粒子が粒子検出センサの内部に付着して検出精度が低下する場合がある。 In addition, in the light scattering type particle detection sensor, particles are detected by introducing gas containing particles such as dust, pollen, smoke, etc., so that the particles adhere to the inside of the particle detection sensor and the detection accuracy decreases. There is a case.
　本発明は、このような課題に鑑みてなされたものであり、内部に粒子が付着することを抑制できる粒子検出センサ等を提供することを第２の目的とする。 This invention is made in view of such a subject, and makes it the 2nd objective to provide the particle | grain detection sensor etc. which can suppress that particle | grains adhere inside.
　また、光散乱式粒子検出センサとして、ヒータによってセンサ内部への大気の導入を促進する技術が知られている（例えば特許文献２、３）。特許文献２に記載された浮遊物検出装置では、さらに、吸気口や排気口からの直射光を遮蔽するために、筐体の内部に遮蔽板を設けている。また、特許文献３に記載された煙検出装置では、空気導入口や空気排出口から外部の光が直接侵入しないように、粒子の流路に迷路を設けている。 Also, as a light scattering type particle detection sensor, a technique for promoting introduction of air into the sensor by a heater is known (for example, Patent Documents 2 and 3). In the floating substance detection apparatus described in Patent Document 2, a shielding plate is further provided inside the housing in order to shield direct light from the air inlet and the air outlet. Further, in the smoke detection device described in Patent Document 3, a maze is provided in the particle flow path so that external light does not directly enter from the air inlet and the air outlet.
　光散乱式粒子検出センサにおいては、検知領域（光散乱部）に進入する迷光を抑制することで粒子の検出精度のさらなる向上が要望されている。 In light scattering type particle detection sensors, further improvement in particle detection accuracy is desired by suppressing stray light entering a detection region (light scattering portion).
　本発明は、このような課題に鑑みてなされたものであり、粒子の検出精度を向上させることができる粒子検出センサ等を提供することを第３の目的とする。 The present invention has been made in view of such problems, and a third object thereof is to provide a particle detection sensor or the like that can improve the detection accuracy of particles.
　上記第１の目的を達成するために、本発明に係る第１の粒子検出センサの一態様は、投光素子と受光素子とを備え、検知領域における粒子による前記投光素子の光の散乱光を前記受光素子で受光することにより気体中に含まれる粒子を検出する粒子検出センサであって、気体を加熱する加熱装置と、前記散乱光を反射して当該散乱光を前記受光素子に導く反射体とを有することを特徴とする。 In order to achieve the first object, one aspect of the first particle detection sensor according to the present invention includes a light projecting element and a light receiving element, and light scattered from the light projecting element by particles in a detection region. A particle detection sensor for detecting particles contained in a gas by receiving light by the light receiving element, a heating device for heating the gas, and a reflection for reflecting the scattered light and guiding the scattered light to the light receiving element And having a body.
　また、上記第２の目的を達成するために、本発明に係る第２の粒子検出センサの一態様は、筐体と、前記筐体内に配置された投光素子と、前記筐体内に配置され、かつ、検知領域における粒子による前記投光素子の光の散乱光を受光する受光素子と、前記筐体内に設けられ、かつ、前記検知領域を含む空間領域であって粒子を含む大気が流れる空間領域である粒子流路と、前記筐体内に設けられ、かつ、前記散乱光を前記受光素子に導くための空間領域である受光領域と、前記粒子流路と前記受光領域との接続部分に配置され、かつ、透光性を有する第１保護板とを備えることを特徴とする。 In order to achieve the second object, one aspect of the second particle detection sensor according to the present invention is a housing, a light projecting element disposed in the housing, and a housing in the housing. And a light receiving element that receives scattered light of the light projecting element due to particles in the detection region, and a space that is provided in the housing and that includes the detection region and flows through the atmosphere including particles. A particle channel that is a region, a light receiving region that is provided in the housing and is a space region for guiding the scattered light to the light receiving element, and a connection portion between the particle channel and the light receiving region And a first protective plate having translucency.
　また、上記第３の目的を達成するために、本発明に係る第３の粒子検出センサの一態様は、投光素子と、検知領域における粒子による前記投光素子からの光の散乱光を受光する受光素子と、大気を加熱するヒータと、前記ヒータから放出されるヒータ光及び外光の少なくとも一方を遮光する遮光体とを備え、前記遮光体は、前記散乱光が当該遮光体に到達した場合に、当該散乱光が前記検知領域に反射することを抑制する形状を有することを特徴とする。 In order to achieve the third object, an aspect of a third particle detection sensor according to the present invention is a light-receiving element and receives light scattered from the light-projecting element by particles in a detection region. A light-receiving element, a heater for heating the atmosphere, and a light-shielding body that shields at least one of heater light and external light emitted from the heater, and the light-scattering body reaches the light-shielding body when the scattered light reaches the light-shielding body In this case, the scattered light has a shape that suppresses reflection of the scattered light to the detection region.
　第１の粒子検出センサの一態様によれば、ヒータ抵抗等の加熱装置によって気流を発生させる加熱方式であっても、微粒子を高精度で検出できる。 According to one aspect of the first particle detection sensor, fine particles can be detected with high accuracy even with a heating method in which an air flow is generated by a heating device such as a heater resistor.
　第２の粒子検出センサの一態様によれば、粒子検出センサの内部に粒子が付着することを抑制できるので、検出精度の低下を抑制できる。 According to one aspect of the second particle detection sensor, it is possible to suppress the adhesion of particles inside the particle detection sensor, and thus it is possible to suppress a decrease in detection accuracy.
　第３の粒子検出センサの一態様によれば、迷光を抑制できるので、粒子の検出精度を向上させることができる。 According to one aspect of the third particle detection sensor, stray light can be suppressed, so that the particle detection accuracy can be improved.
図１の（ａ）は、実施の形態１に係る粒子検出センサの上面図、図１の（ｂ）は、同粒子検出センサの正面図、図１の（ｃ）は、同粒子検出センサの下面図、図１の（ｄ）は、図１の（ａ）のＡ－Ａ線における同粒子検出センサの断面図である。1A is a top view of the particle detection sensor according to Embodiment 1, FIG. 1B is a front view of the particle detection sensor, and FIG. 1C is a view of the particle detection sensor. FIG. 1D is a bottom view, and FIG. 1D is a cross-sectional view of the particle detection sensor taken along line AA in FIG. 図２Ａは、気体中に粒子が存在しない場合における粒子検出センサの動作を説明するための断面図である。FIG. 2A is a cross-sectional view for explaining the operation of the particle detection sensor when there is no particle in the gas. 図２Ｂは、気体中に粒径の小さい粒子が存在する場合における粒子検出センサの動作を説明するための断面図である。FIG. 2B is a cross-sectional view for explaining the operation of the particle detection sensor when there are particles having a small particle diameter in the gas. 図２Ｃは、気体中に粒径の大きい粒子が存在する場合における粒子検出センサの動作を説明するための断面図である。FIG. 2C is a cross-sectional view for explaining the operation of the particle detection sensor when particles having a large particle diameter are present in the gas. 図３は、比較例１の粒子検出センサの断面図である。FIG. 3 is a cross-sectional view of the particle detection sensor of Comparative Example 1. 図４は、実施の形態１に係る粒子検出センサの断面図である。FIG. 4 is a cross-sectional view of the particle detection sensor according to the first embodiment. 図５は、実施の形態１に係る粒子検出センサにおける反射体と受光素子と検知領域との位置関係を説明するための図である。FIG. 5 is a diagram for explaining the positional relationship among the reflector, the light receiving element, and the detection region in the particle detection sensor according to the first embodiment. 図６の（ａ）は、実施の形態２に係る粒子検出センサの上面図、図６の（ｂ）は、同粒子検出センサの正面図、図６の（ｃ）は、同粒子検出センサの下面図、図６の（ｄ）は、図６の（ａ）のＡ－Ａ線における同粒子検出センサの断面図である。6 (a) is a top view of the particle detection sensor according to Embodiment 2, FIG. 6 (b) is a front view of the particle detection sensor, and FIG. 6 (c) is the particle detection sensor. FIG. 6D is a bottom view, and FIG. 6D is a cross-sectional view of the particle detection sensor taken along line AA in FIG. 図７は、実施の形態２に係る粒子検出センサにおける反射体と投光素子と受光素子と検知領域との位置関係を説明するための図である。FIG. 7 is a diagram for explaining a positional relationship among a reflector, a light projecting element, a light receiving element, and a detection region in the particle detection sensor according to the second embodiment. 図８Ａは、実施の形態２に係る粒子検出センサにおける第１遮光体周辺の構成を示す拡大断面図である。FIG. 8A is an enlarged cross-sectional view showing a configuration around a first light shield in the particle detection sensor according to Embodiment 2. 図８Ｂは、実施の形態２に係る粒子検出センサにおける第２遮光体周辺の構成を示す拡大断面図である。FIG. 8B is an enlarged cross-sectional view illustrating a configuration around a second light shielding body in the particle detection sensor according to Embodiment 2. 図９は、実施の形態２に係る粒子検出センサにおける投光素子から出射して検知領域に向かう光の光路を説明するための図である。FIG. 9 is a diagram for explaining an optical path of light emitted from the light projecting element in the particle detection sensor according to Embodiment 2 and traveling toward the detection region. 図１０の（ａ）は、実施の形態３に係る粒子検出センサの上面図、図１０の（ｂ）は、同粒子検出センサの正面図、図１０の（ｃ）は、同粒子検出センサの下面図、図１０の（ｄ）は、図１０の（ａ）のＡ－Ａ線における同粒子検出センサの断面図である。10A is a top view of the particle detection sensor according to Embodiment 3, FIG. 10B is a front view of the particle detection sensor, and FIG. 10C is the particle detection sensor. FIG. 10D is a bottom view, and FIG. 10D is a cross-sectional view of the particle detection sensor taken along line AA in FIG. 図１１Ａは、比較例２の粒子検出センサの断面図である。FIG. 11A is a cross-sectional view of the particle detection sensor of Comparative Example 2. 図１１Ｂは、図１１Ａに示す比較例２の粒子検出センサの内部を清掃するときの様子を示す同粒子検出センサの要部拡大断面図である。FIG. 11B is an enlarged cross-sectional view of a main part of the particle detection sensor showing a state when the inside of the particle detection sensor of Comparative Example 2 shown in FIG. 11A is cleaned. 図１２は、実施の形態３の変形例１に係る粒子検出センサの構成を示す断面図である。FIG. 12 is a cross-sectional view illustrating a configuration of a particle detection sensor according to Modification 1 of Embodiment 3. 図１３は、実施の形態３の変形例２に係る粒子検出センサの構成を示す断面図である。FIG. 13 is a cross-sectional view illustrating a configuration of a particle detection sensor according to Modification 2 of Embodiment 3. 図１４は、実施の形態３の変形例３に係る粒子検出センサの構成を示す断面図である。FIG. 14 is a cross-sectional view illustrating a configuration of a particle detection sensor according to Modification 3 of Embodiment 3. 図１５の（ａ）は、実施の形態３の変形例４に係る粒子検出センサの上面図、図１５の（ｂ）は、同粒子検出センサの正面図、図１５の（ｃ）は、同粒子検出センサの下面図、図１５の（ｄ）は、図１５の（ａ）のＡ－Ａ線における同粒子検出センサの断面図である。15A is a top view of a particle detection sensor according to Modification 4 of Embodiment 3, FIG. 15B is a front view of the particle detection sensor, and FIG. FIG. 15D is a bottom view of the particle detection sensor, and FIG. 15D is a cross-sectional view of the particle detection sensor taken along line AA in FIG. 図１６Ａは、実施の形態３の変形例４に係る粒子検出センサの筐体内を清掃（メンテナンス）するときの様子を示す斜視図である。FIG. 16A is a perspective view illustrating a state when cleaning (maintenance) of the inside of the housing of the particle detection sensor according to the fourth modification of the third embodiment. 図１６Ｂは、実施の形態３の変形例４に係る粒子検出センサの筐体内を清掃（メンテナンス）するときの様子を示す断面図である。FIG. 16B is a cross-sectional view illustrating a state when cleaning (maintenance) of the inside of the housing of the particle detection sensor according to Modification 4 of Embodiment 3. 図１７は、変形例１に係る粒子検出センサの概略構成を示す断面図である。FIG. 17 is a cross-sectional view illustrating a schematic configuration of the particle detection sensor according to the first modification. 図１８は、変形例１の他の形態に係る粒子検出センサの概略構成を示す断面図である。FIG. 18 is a cross-sectional view illustrating a schematic configuration of a particle detection sensor according to another embodiment of the first modification. 図１９は、変形例２に係る粒子検出センサの概略構成を示す断面図である。FIG. 19 is a cross-sectional view illustrating a schematic configuration of a particle detection sensor according to Modification 2. 図２０は、変形例３に係る粒子検出センサの概略構成を示す断面図である。FIG. 20 is a cross-sectional view illustrating a schematic configuration of a particle detection sensor according to Modification 3. 図２１は、変形例４に係る粒子検出センサの概略構成を示す断面図である。FIG. 21 is a cross-sectional view illustrating a schematic configuration of a particle detection sensor according to Modification 4. 図２２は、変形例４の他の形態に係る粒子検出センサの概略構成を示す断面図である。FIG. 22 is a cross-sectional view illustrating a schematic configuration of a particle detection sensor according to another embodiment of the fourth modification. 図２３は、変形例５に係る粒子検出センサの概略構成を示す断面図である。FIG. 23 is a cross-sectional view illustrating a schematic configuration of a particle detection sensor according to Modification 5. 図２４は、変形例６に係る粒子検出センサの概略構成を示す断面図である。FIG. 24 is a cross-sectional view illustrating a schematic configuration of a particle detection sensor according to Modification 6. 図２５の（ａ）は、変形例７に係る粒子検出センサの上面図、図２５の（ｂ）は、同粒子検出センサの正面図、図２５の（ｃ）は、同粒子検出センサの下面図、図２５の（ｄ）は、図２５の（ｂ）のＢ－Ｂ線における同粒子検出センサの断面図である。25A is a top view of the particle detection sensor according to the modified example 7, FIG. 25B is a front view of the particle detection sensor, and FIG. 25C is a bottom surface of the particle detection sensor. FIG. 25D is a cross-sectional view of the particle detection sensor taken along line BB in FIG. 図２６は、粒子検出センサを備える煙感知器の外観図である。FIG. 26 is an external view of a smoke detector including a particle detection sensor. 図２７は、粒子検出センサを備える空気清浄機の外観図である。FIG. 27 is an external view of an air cleaner provided with a particle detection sensor. 図２８は、粒子検出センサを備える換気扇の外観図である。FIG. 28 is an external view of a ventilation fan provided with a particle detection sensor. 図２９は、粒子検出センサを備えるエアコンの外観図である。FIG. 29 is an external view of an air conditioner including a particle detection sensor.
　以下、本発明の実施の形態について、図面を参照しながら説明する。以下に説明する実施の形態は、いずれも本発明の好ましい一具体例を示すものである。したがって、以下の実施の形態で示される数値、形状、材料、構成要素、構成要素の配置位置及び接続形態等は、一例であって本発明を限定する主旨ではない。よって、以下の実施の形態における構成要素のうち、本発明の最上位概念を示す独立請求項に記載されていない構成要素については、任意の構成要素として説明される。 Hereinafter, embodiments of the present invention will be described with reference to the drawings. Each of the embodiments described below shows a preferred specific example of the present invention. Accordingly, numerical values, shapes, materials, components, arrangement positions and connection forms of components shown in the following embodiments are merely examples, and are not intended to limit the present invention. Therefore, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims showing the highest concept of the present invention are described as optional constituent elements.
　なお、各図は、模式図であり、必ずしも厳密に図示されたものではない。また、各図において、実質的に同一の構成に対しては同一の符号を付しており、重複する説明は省略又は簡略化する。 Each figure is a schematic diagram and is not necessarily shown strictly. Moreover, in each figure, the same code | symbol is attached | subjected to the substantially same structure, The overlapping description is abbreviate | omitted or simplified.
　（実施の形態１）
　まず、実施の形態１に係る粒子検出センサ１の構成について、図１を用いて説明する。図１は、実施の形態１に係る粒子検出センサ１の構成を示す図であり、（ａ）は上面図、（ｂ）は正面図、（ｃ）は下面図、（ｄ）は（ａ）のＡ－Ａ線における断面図である。なお、本実施の形態では、図１（ｄ）における大気排出孔３６から大気導入孔３５に向かう方向を鉛直下方（重力方向）としている。 (Embodiment 1)
First, the configuration of the particle detection sensor 1 according to Embodiment 1 will be described with reference to FIG. FIG. 1 is a diagram illustrating a configuration of a particle detection sensor 1 according to Embodiment 1, wherein (a) is a top view, (b) is a front view, (c) is a bottom view, and (d) is (a). It is sectional drawing in the AA of FIG. In the present embodiment, the direction from the air discharge hole 36 to the air introduction hole 35 in FIG. 1D is the vertically downward direction (the direction of gravity).
　図１に示すように、粒子検出センサ１は、投光素子１０と受光素子２０とを備える光電式センサであって、検知領域（光拡散部）ＤＡにおける粒子による投光素子１０からの光の散乱光を受光素子２０で受光することにより気体中に含まれる粒子を検出するものである。 As shown in FIG. 1, the particle detection sensor 1 is a photoelectric sensor including a light projecting element 10 and a light receiving element 20, and the light from the light projecting element 10 due to particles in a detection region (light diffusion part) DA. The scattered light is received by the light receiving element 20 to detect particles contained in the gas.
　本実施の形態における粒子検出センサ１は、さらに、筐体（ケース）３０と、反射面を有する反射体４０と、気体を加熱する加熱装置５０とを有する。反射体４０及び加熱装置５０は、筐体３０内に配置される。 The particle detection sensor 1 according to the present embodiment further includes a housing (case) 30, a reflector 40 having a reflecting surface, and a heating device 50 that heats gas. The reflector 40 and the heating device 50 are disposed in the housing 30.
　投光素子１０は、所定の波長の光を発する光源（発光部）であり、例えば、ＬＥＤや半導体レーザ等の固体発光素子である。投光素子１０としては、赤外光、青色光、緑色光、赤色光又は紫外光を発する発光素子を用いることができる。この場合、２波長以上の混合波を発するように構成してもよい。 The light projecting element 10 is a light source (light emitting unit) that emits light of a predetermined wavelength, and is, for example, a solid light emitting element such as an LED or a semiconductor laser. As the light projecting element 10, a light emitting element that emits infrared light, blue light, green light, red light, or ultraviolet light can be used. In this case, you may comprise so that the mixed wave of 2 wavelengths or more may be emitted.
　なお、投光素子１０の発光波長が短いほど、粒径の小さな粒子を検出しやすくなる。また、投光素子１０の発光制御方式は特に限定されるものではなく、投光素子１０から出射する光は、ＤＣ駆動による連続光又はパルス光等とすることができる。また、投光素子１０の出力の大きさは、時間的に変化していてもよい。 In addition, it becomes easy to detect a particle | grain with a small particle size, so that the light emission wavelength of the light projection element 10 is short. Moreover, the light emission control system of the light projecting element 10 is not particularly limited, and the light emitted from the light projecting element 10 can be continuous light or pulsed light by DC driving. Moreover, the magnitude | size of the output of the light projection element 10 may be changing temporally.
　受光素子２０は、光を受ける受光部であり、例えば、フォトダイオード、フォトＩＣダイオード、フォトトランジスタ、又は、高電子倍増管等、光を受けて電気信号に変換する素子（光検出器）である。 The light receiving element 20 is a light receiving unit that receives light, and is an element (photodetector) that receives light and converts it into an electric signal, such as a photodiode, a photo IC diode, a phototransistor, or a high electron multiplier. .
　図１（ｄ）に示すように、投光素子１０及び受光素子２０は、筐体３０内に配置される。筐体３０は、投光素子１０及び受光素子２０を保持するように構成されている。本実施の形態において、投光素子１０及び受光素子２０は、それぞれの光軸を交差させる形で筐体３０内に配置されている。 As shown in FIG. 1 (d), the light projecting element 10 and the light receiving element 20 are arranged in a housing 30. The housing 30 is configured to hold the light projecting element 10 and the light receiving element 20. In the present embodiment, the light projecting element 10 and the light receiving element 20 are disposed in the housing 30 so that their optical axes intersect.
　受光素子２０での受光感度を大きくするには、検知領域ＤＡの粒子の散乱光のうち前方散乱光を多く取得するとよい。この場合、投光素子１０の光軸と受光素子２０の光軸とを一致させることによって前方散乱光を容易に取得することができるが、単に投光素子１０と受光素子２０との光軸を一致させただけでは、受光素子２０には前方散乱光以外に投光素子１０からの直接光が入射してしまうことになり、粒子の検出精度が低下してしまう。 In order to increase the light receiving sensitivity of the light receiving element 20, it is preferable to acquire a lot of forward scattered light among the scattered light of the particles in the detection area DA. In this case, the forward scattered light can be easily obtained by matching the optical axis of the light projecting element 10 and the optical axis of the light receiving element 20, but the optical axes of the light projecting element 10 and the light receiving element 20 are simply changed. If they are just matched, the light receiving element 20 will receive direct light from the light projecting element 10 in addition to the forward scattered light, and the particle detection accuracy will be reduced.
　このため、本実施の形態では、投光素子１０及び受光素子２０の各々の光軸を交差させている。一例として、投光素子１０の光軸と受光素子２０の光軸とのなす角は６０度（１２０度）である。 Therefore, in the present embodiment, the optical axes of the light projecting element 10 and the light receiving element 20 are crossed. As an example, the angle formed by the optical axis of the light projecting element 10 and the optical axis of the light receiving element 20 is 60 degrees (120 degrees).
　このように、投光素子１０及び受光素子２０の各々の光軸を交差させることによって、投光素子１０からの直接光の影響を受けることなく、前方散乱光に近い部分の側方散乱光を取得できるので、粒子の検出精度の低下を抑制できる。 In this way, by causing the optical axes of the light projecting element 10 and the light receiving element 20 to cross each other, the side scattered light in a portion close to the forward scattered light is not affected by the direct light from the light projecting element 10. Since it can acquire, the fall of the detection accuracy of particle | grains can be suppressed.
　図１の（ａ）～（ｃ）に示すように、筐体３０の外形は、一例として扁平直方体である。筐体３０は、第１筐体部３０ａ（蓋部）と第２筐体部３０ｂとの２つの部材によって構成されている。第２筐体部３０ｂからは、複数のリード線１１、２１及び５１が露出している。リード線１１、２１及び５１は、それぞれ、投光素子１０、受光素子２０及び加熱装置５０と電気的に接続されている。 As shown in FIGS. 1A to 1C, the outer shape of the housing 30 is, for example, a flat rectangular parallelepiped. The housing 30 is composed of two members, a first housing portion 30a (lid portion) and a second housing portion 30b. A plurality of lead wires 11, 21, and 51 are exposed from the second housing portion 30b. The lead wires 11, 21, and 51 are electrically connected to the light projecting element 10, the light receiving element 20, and the heating device 50, respectively.
　筐体３０には、投光素子１０の光が投光される空間領域である投光領域３１と、検知領域ＤＡにおいて投光素子１０の光が粒子に当たって発生した散乱光を受光素子２０に導くための空間領域である受光領域３２（拡散光導入部）と、粒子を含む気体（大気等）が流れる空間領域である粒子流路３３と、トラップ部３４とが設けられている。 In the housing 30, a light projecting region 31, which is a space region in which light from the light projecting element 10 is projected, and scattered light generated when the light from the light projecting device 10 hits particles in the detection region DA is guided to the light receiving device 20. For this purpose, a light receiving region 32 (diffused light introducing portion) that is a space region for the particles, a particle flow path 33 that is a space region through which a gas (such as the atmosphere) containing particles flows, and a trap portion 34 are provided.
　投光領域３１、受光領域３２、粒子流路３３及びトラップ部３４の各々は、筐体３０における空間領域である。投光領域３１は、投光素子１０から検知領域ＤＡまでの空間領域である。受光領域３２は、検知領域ＤＡから受光素子２０までの空間領域である。 Each of the light projecting area 31, the light receiving area 32, the particle flow path 33 and the trap part 34 is a space area in the housing 30. The light projection area 31 is a spatial area from the light projecting element 10 to the detection area DA. The light receiving area 32 is a spatial area from the detection area DA to the light receiving element 20.
　例えば、図１（ｄ）に示すように、投光領域３１、受光領域３２及びトラップ部３４の各々は、周囲が筐体３０の内面（内壁）で囲まれた略円筒状又は略角筒状の有底筒状の空間領域であり、粒子流路３３との接続部分に開口部を有している。つまり、投光領域３１、受光領域３２及びトラップ部３４の各々は、各開口部が粒子流路３３に向かって開口しており、各開口部において粒子流路３３と接続されている。本実施の形態において、投光領域３１、受光領域３２及びトラップ部３４の各々の開口部は、検知領域ＤＡに向かって開口している。 For example, as shown in FIG. 1 (d), each of the light projecting region 31, the light receiving region 32, and the trap portion 34 has a substantially cylindrical shape or a substantially rectangular tube shape that is surrounded by the inner surface (inner wall) of the housing 30. The bottomed cylindrical space region has an opening at a connection portion with the particle channel 33. In other words, each of the light projecting region 31, the light receiving region 32, and the trap portion 34 has an opening that opens toward the particle channel 33, and is connected to the particle channel 33 at each opening. In the present embodiment, each opening of the light projecting area 31, the light receiving area 32, and the trap part 34 opens toward the detection area DA.
　粒子流路３３は、粒子を含む大気（気体）が流れる領域である。具体的には、粒子流路３３は、筐体３０内に導入された気体が通過する気体通過領域であり、周囲が筐体３０の内面（内壁）で囲まれた空間領域である。つまり、粒子流路３３は、検知領域ＤＡを含む空間領域であり、大気導入孔３５から導入した大気が検知領域ＤＡを通って大気排出孔３６から排出されるまでの筐体３０内の空間領域である。 The particle channel 33 is a region through which air (gas) containing particles flows. Specifically, the particle flow path 33 is a gas passage region through which the gas introduced into the housing 30 passes, and is a space region surrounded by the inner surface (inner wall) of the housing 30. That is, the particle flow path 33 is a space area including the detection area DA, and the space area in the housing 30 until the air introduced from the air introduction hole 35 is discharged from the air discharge hole 36 through the detection area DA. It is.
　本実施の形態において、粒子流路３３は、略円筒状又は略角筒状の筒状空間領域であり、検知領域ＤＡ全体を含んでいる。また、粒子流路３３は、大気導入孔３５から大気排出孔３６に向かって真っ直ぐな流路となっており、その途中で、投光領域３１、受光領域３２及びトラップ部３４と接続されている。 In the present embodiment, the particle flow path 33 is a cylindrical space region having a substantially cylindrical shape or a substantially rectangular tube shape, and includes the entire detection region DA. The particle flow path 33 is a straight flow path from the air introduction hole 35 toward the air discharge hole 36, and is connected to the light projecting area 31, the light receiving area 32, and the trap part 34 in the middle of the flow path. .
　また、投光領域３１、受光領域３２、粒子流路３３及びトラップ部３４における筐体３０の内面（壁面）は、迷光を吸収させるために黒色であるとよい。例えば、筐体３０を黒色の樹脂成型品であり、内部に露出部分は少なくとも黒色表面となっている。また、筐体３０の内面にシボ加工などの表面処理を行うことによって迷光を吸収させるように構成されていてもよい。 Further, the inner surface (wall surface) of the housing 30 in the light projecting region 31, the light receiving region 32, the particle flow path 33, and the trap part 34 is preferably black in order to absorb stray light. For example, the housing 30 is a black resin molded product, and the exposed part has at least a black surface inside. Further, the inner surface of the housing 30 may be configured to absorb stray light by performing a surface treatment such as embossing.
　検知領域ＤＡは、測定対象の気体に含まれる粒子（エアロゾル）を検知するための領域であるエアロゾル検知領域（エアロゾル測定部）である。検知領域ＤＡは、粒子流路３３内に存在するように設定されており、本実施の形態では、投光領域３１と受光領域３２とが粒子流路３３で重なる領域である。具体的には、検知領域ＤＡは、投光素子１０の光軸と受光素子２０の光軸とが交差する交点を含む領域である。測定対象の気体は、大気導入孔３５から粒子流路３３を通って検知領域ＤＡに導かれる。検知領域ＤＡは、例えばφ２ｍｍである。 The detection area DA is an aerosol detection area (aerosol measurement unit) that is an area for detecting particles (aerosol) contained in the gas to be measured. The detection area DA is set so as to exist in the particle flow path 33, and in the present embodiment, the light projection area 31 and the light reception area 32 overlap with the particle flow path 33. Specifically, the detection area DA is an area including an intersection where the optical axis of the light projecting element 10 and the optical axis of the light receiving element 20 intersect. The gas to be measured is guided from the atmosphere introduction hole 35 to the detection area DA through the particle flow path 33. The detection area DA is, for example, φ2 mm.
　トラップ部３４は、投光素子１０の光のうち検知領域ＤＡで粒子に当たらずに検知領域ＤＡを通過した光が筐体３０内で反射及び散乱して受光素子２０で受光されてしまうことを防止する構造を有する。具体的に、トラップ部３４は、光トラップ構造を有し、トラップ部３４の内部に一旦進入した光がトラップ部３４から出て行かないような光吸収構造を有する。例えば、トラップ部３４における筐体３０の内面には、多重反射させて光を吸収させるための複数の黒色突起が設けられる。なお、トラップ部３４は、ラビリンス構造であってもよい。 The trap part 34 reflects that the light that has passed through the detection area DA without hitting the particles in the detection area DA out of the light from the light projecting element 10 is reflected and scattered in the housing 30 and received by the light receiving element 20. It has a structure to prevent. Specifically, the trap unit 34 has an optical trap structure, and has a light absorption structure that prevents light once entering the trap unit 34 from exiting the trap unit 34. For example, the inner surface of the housing 30 in the trap portion 34 is provided with a plurality of black protrusions for multiple reflection and absorption of light. The trap part 34 may have a labyrinth structure.
　本実施の形態において、トラップ部３４（光トラップ構造）は、投光素子１０と対向する位置に設けられている。具体的には、トラップ部３４の開口部が投光領域３１の開口部に対向している。なお、本実施の形態において、トラップ部３４は、投光素子１０と対向する位置にのみ設けられているが、投光素子１０及び受光素子２０の両方と対向する位置に設けられていてもよいし、受光素子２０と対向する位置にのみ設けられていてもよい。但し、受光素子２０と対向する位置にのみトラップ部３４を設ける場合、トラップ部３４の内部に一旦進入した光が戻って行かないように、トラップ部３４を貫通孔にする等の手段を設けるとよい。 In the present embodiment, the trap portion 34 (light trap structure) is provided at a position facing the light projecting element 10. Specifically, the opening of the trap portion 34 faces the opening of the light projecting region 31. In the present embodiment, the trap portion 34 is provided only at a position facing the light projecting element 10, but may be provided at a position facing both the light projecting element 10 and the light receiving element 20. However, it may be provided only at a position facing the light receiving element 20. However, when the trap portion 34 is provided only at a position facing the light receiving element 20, it is possible to provide a means such as making the trap portion 34 a through hole so that the light that has once entered the trap portion 34 does not return. Good.
　また、筐体３０には、粒子流路３３に大気を導入するための大気導入孔３５と、粒子流路３３から大気を排出するための大気排出孔（大気放出孔）３６とが設けられている。 The housing 30 is provided with an air introduction hole 35 for introducing air into the particle flow path 33 and an air discharge hole (atmospheric discharge hole) 36 for discharging air from the particle flow path 33. Yes.
　大気導入孔３５は、粒子検出センサ１の外部に存在する大気等の気体を粒子検出センサ１の内部（粒子流路３３）に供給するための大気供給口（大気流入口）であり、筐体３０における大気の入口である。 The atmosphere introduction hole 35 is an atmosphere supply port (atmosphere inlet) for supplying a gas such as the atmosphere existing outside the particle detection sensor 1 to the inside of the particle detection sensor 1 (particle flow path 33). 30 is the atmospheric inlet.
　一方、大気排出孔３６は、粒子検出センサ１の内部（粒子流路３３）の大気を粒子検出センサ１の外部に排出するための大気排気口（大気流出口）であり、筐体３０における大気の出口である。 On the other hand, the air discharge hole 36 is an air exhaust port (atmosphere outlet) for discharging the air inside the particle detection sensor 1 (particle flow path 33) to the outside of the particle detection sensor 1. Is the exit.
　大気導入孔３５は、粒子流路３３の一方に繋がっており、大気排出孔３６は、粒子流路３３の他方に繋がっている。これにより、粒子を含む大気（測定対象の気体）は、大気導入孔３５から筐体３０内に導入されて粒子流路３３を通って検知領域ＤＡに流入され、大気排出孔３６から筐体３０外に排出される。本実施の形態では、効率良く筐体３０内に気体を導入して排気するために、大気導入孔３５の方が大気排出孔３６よりも開口面積が大きくなっている。 The air introduction hole 35 is connected to one of the particle flow paths 33, and the air discharge hole 36 is connected to the other of the particle flow paths 33. Thereby, the atmosphere containing the particles (the gas to be measured) is introduced into the casing 30 from the atmosphere introduction hole 35 and flows into the detection area DA through the particle flow path 33, and from the atmosphere discharge hole 36 to the casing 30. Discharged outside. In the present embodiment, the air introduction hole 35 has a larger opening area than the air discharge hole 36 in order to efficiently introduce and exhaust gas into the housing 30.
　また、本実施の形態において、投光領域３１には、投光レンズ（発光レンズ）３１ａが設けられている。投光レンズ３１ａは、投光素子１０の前方に配置されており、投光素子１０から出射する光（投光ビーム）を検知領域ＤＡに向けて進行させるように構成されている。つまり、投光素子１０から出射する光は投光レンズ３１ａを介して検知領域ＤＡに到達する。投光レンズ３１ａは、例えば、透明樹脂レンズ又はガラスレンズである。 In the present embodiment, the light projecting area 31 is provided with a light projecting lens (light emitting lens) 31a. The light projecting lens 31a is disposed in front of the light projecting element 10, and is configured to advance light (projected beam) emitted from the light projecting element 10 toward the detection area DA. That is, the light emitted from the light projecting element 10 reaches the detection area DA via the light projecting lens 31a. The light projection lens 31a is, for example, a transparent resin lens or a glass lens.
　投光レンズ３１ａは、投光素子１０から出射する光を検知領域ＤＡに向けてコリメートさせるコリメートレンズであってもよいし、投光素子１０から出射する光を検知領域ＤＡに集光させる集光レンズであってもよいが、投光レンズ３１ａとしては、検知領域ＤＡにおいて投光素子１０の光強度を大きくするようなレンズを用いるとよい。また、検知領域ＤＡ内の場所によって光強度が異なると、同じ粒径の粒子であっても検知領域ＤＡ内の場所によって散乱光の強度が異なってしまうので、投光レンズ３１ａとしては、投光素子１０の光の強度分布が検知領域ＤＡ全体で均一になるようなレンズを用いるとよい。さらに、投光素子１０の光が筐体３０の壁面に反射すると無用な反射光及び散乱光が発生することになるので、投光レンズ３１ａとしては、投光素子１０の光が投光領域３１における筐体３０の壁面に反射することなく直接検知領域ＤＡに到達するようなレンズを用いるとよい。なお、投光レンズ３１ａは、設けなくてもよい。 The light projecting lens 31a may be a collimating lens that collimates the light emitted from the light projecting element 10 toward the detection area DA, or the light that collects the light emitted from the light projecting element 10 on the detection area DA. Although a lens may be used, a lens that increases the light intensity of the light projecting element 10 in the detection area DA may be used as the light projecting lens 31a. Further, if the light intensity varies depending on the location in the detection area DA, the intensity of the scattered light varies depending on the location in the detection area DA even if the particles have the same particle size. A lens that makes the light intensity distribution of the element 10 uniform in the entire detection area DA may be used. Further, if the light of the light projecting element 10 is reflected on the wall surface of the housing 30, unnecessary reflected light and scattered light are generated. Therefore, the light of the light projecting element 10 is used as the light projecting area 31. It is preferable to use a lens that directly reaches the detection area DA without being reflected by the wall surface of the housing 30 in FIG. The light projection lens 31a may not be provided.
　また、本実施の形態において、投光領域３１には発光絞り部３１ｂが設けられている。発光絞り部３１ｂは、投光レンズ３１ａを通過した後の投光素子１０の光を絞って不要な光を遮蔽して集光径を小さくする。発光絞り部３１ｂは、樹脂等からなり、投光領域３１の内壁に所定の形状で形成されている。発光絞り部３１ｂは、各々が円形や多角形などの開口（スリット）を有する複数の光学絞りからなる。本実施の形態において、発光絞り部３１ｂ（光学絞り）は、投光領域３１の内壁から突出するように形成されている。発光絞り部３１ｂ（光学絞り）は、樹脂等からなり、筐体３０と一体成型されていてもよいし、筐体３０と別体であってもよい。 Further, in the present embodiment, the light emission area 31 is provided with a light emission stop portion 31b. The light emission diaphragm 31b narrows the light of the light projecting element 10 after passing through the light projecting lens 31a to shield unnecessary light and reduce the condensed diameter. The light emission diaphragm 31b is made of resin or the like, and is formed in a predetermined shape on the inner wall of the light projecting region 31. The light emission diaphragm 31b is composed of a plurality of optical diaphragms each having a circular or polygonal opening (slit). In the present embodiment, the light emission stop portion 31 b (optical stop) is formed so as to protrude from the inner wall of the light projecting region 31. The light emission diaphragm 31b (optical diaphragm) is made of resin or the like, and may be integrally formed with the housing 30 or may be separate from the housing 30.
　反射体４０（反射板）は、検知領域ＤＡにおける粒子による投光素子１０の光の散乱光を反射して当該散乱光を受光素子２０に導く反射部材である。本実施の形態において、反射体４０は、粒子の散乱光を反射して受光素子２０に集光させている。より具体的には、反射体４０は、粒子の散乱光を受光素子２０に向けて反射している。 The reflector 40 (reflecting plate) is a reflecting member that reflects scattered light of the light projecting element 10 by particles in the detection area DA and guides the scattered light to the light receiving element 20. In the present embodiment, the reflector 40 reflects the scattered light of the particles and collects it on the light receiving element 20. More specifically, the reflector 40 reflects the scattered light of the particles toward the light receiving element 20.
　図１（ｄ）に示すように、本実施の形態では、反射体４０は、受光領域３２に設けられている。具体的には、反射体４０は、受光領域３２における筐体３０の内面に沿って設けられた集光ミラーであり、反射面である内面が曲面となっている。図１（ｄ）に示すように、反射体４０の内面は、回転楕円体の回転面の一部である。つまり、反射体４０は、内面（反射面）の形状が回転楕円面の一部の形状をなす楕円ミラーであり、反射体４０の内面の断面形状は楕円の一部である。反射体４０の内面は、主に正反射特性をもつ平滑面あるいは鏡面であるが、これに限るものではない。 As shown in FIG. 1 (d), the reflector 40 is provided in the light receiving region 32 in the present embodiment. Specifically, the reflector 40 is a condensing mirror provided along the inner surface of the housing 30 in the light receiving region 32, and the inner surface which is a reflecting surface is a curved surface. As shown in FIG.1 (d), the inner surface of the reflector 40 is a part of rotation surface of a spheroid. That is, the reflector 40 is an elliptical mirror in which the shape of the inner surface (reflecting surface) forms a part of the spheroid, and the cross-sectional shape of the inner surface of the reflector 40 is a part of the ellipse. The inner surface of the reflector 40 is mainly a smooth surface or a mirror surface having regular reflection characteristics, but is not limited thereto.
　また、反射体４０は、粒子流路３３に向かって開口する開口部を有する。具体的には、反射体４０の開口部は、検知領域ＤＡに向かって開口している。本実施の形態において、反射体４０の開口部は、受光領域３２の開口部と略一致している。つまり、反射体４０は、受光領域３２の開口部近傍まで設けられている。 Further, the reflector 40 has an opening that opens toward the particle channel 33. Specifically, the opening of the reflector 40 opens toward the detection area DA. In the present embodiment, the opening of the reflector 40 substantially coincides with the opening of the light receiving region 32. That is, the reflector 40 is provided up to the vicinity of the opening of the light receiving region 32.
　反射体４０としては、ベース部材の表面そのものが反射面となるようにベース部材そのものを金属等の反射材料で構成してもよいし、樹脂や金属のベース部材の表面に反射面となる反射膜を形成してもよい。 As the reflector 40, the base member itself may be made of a reflective material such as metal so that the surface of the base member itself becomes a reflective surface, or a reflective film that becomes a reflective surface on the surface of a resin or metal base member May be formed.
　反射膜としては、アルミニウム、金、銀や銅等の金属反射膜、鏡面反射膜、又は、誘電体多層膜等を用いることができる。反射膜としては、吸収率が小さく、高い反射率を有するものがよい。また、反射膜として、蒸着等で形成したアルミニウム膜の表面に当該アルミニウム膜よりも薄い薄膜を積層したものを用いてもよい。アルミニウム膜に積層する薄膜としては、例えば、ＭｇＦ膜、ＳｉＯ２膜、ＳｉＯ膜、ＡｌＮ膜、アルミナ膜、又は、増反射膜等が用いられる。このように、アルミニウム膜にこれらの薄膜を積層することによって、アルミニウム膜の劣化（腐食等）を抑制したり光増幅による光学特性を向上させたりすることができる。 As the reflection film, a metal reflection film such as aluminum, gold, silver or copper, a mirror reflection film, a dielectric multilayer film, or the like can be used. As the reflective film, a film having a low absorptance and a high reflectance is preferable. Moreover, you may use as a reflecting film what laminated | stacked the thin film thinner than the said aluminum film on the surface of the aluminum film formed by vapor deposition. As the thin film laminated on the aluminum film, for example, an MgF film, a SiO 2 film, a SiO film, an AlN film, an alumina film, an enhanced reflection film, or the like is used. Thus, by laminating these thin films on the aluminum film, it is possible to suppress deterioration (corrosion and the like) of the aluminum film and improve optical characteristics by optical amplification.
　加熱装置５０は、大気を加熱するヒータである。加熱装置５０は、粒子流路３３内に流れる気体の流れを促進させるための気流を発生させる気流発生装置として機能する。つまり、加熱装置５０によって大気を加熱することで、粒子を含む大気を検知領域ＤＡに導入しやすくできる。加熱装置５０は、例えば、低コストで入手可能なヒータ抵抗等である。 The heating device 50 is a heater that heats the atmosphere. The heating device 50 functions as an airflow generation device that generates an airflow for promoting the flow of gas flowing in the particle flow path 33. That is, the atmosphere including particles can be easily introduced into the detection area DA by heating the atmosphere with the heating device 50. The heating device 50 is, for example, a heater resistor that can be obtained at low cost.
　図１（ｄ）に示すように、本実施の形態において、加熱装置５０は、粒子流路３３内に配置されている。つまり、加熱装置５０は、粒子流路３３内の気体を加熱する。なお、加熱装置５０は、大気導入孔３５の近傍に配置されている。 As shown in FIG. 1 (d), in the present embodiment, the heating device 50 is disposed in the particle channel 33. That is, the heating device 50 heats the gas in the particle channel 33. The heating device 50 is disposed in the vicinity of the air introduction hole 35.
　また、加熱装置５０は、検知領域ＤＡの鉛直下方に配置されている。これにより、加熱装置５０がヒータ抵抗である場合、ヒータ抵抗に電圧を印加するとヒータ抵抗が発熱してヒータ抵抗の周囲の大気が加熱されて密度が小さくなり、重力とは逆方向の鉛直方向に移動する。つまり、加熱装置５０によって粒子流路３３内の気体を加熱すると、上方向の気流（上昇気流）を発生させることができる。 Further, the heating device 50 is disposed vertically below the detection area DA. As a result, when the heating device 50 is a heater resistor, when a voltage is applied to the heater resistor, the heater resistor generates heat, the atmosphere around the heater resistor is heated, the density is reduced, and the vertical direction is opposite to gravity. Moving. That is, when the gas in the particle channel 33 is heated by the heating device 50, an upward airflow (upward airflow) can be generated.
　このように、加熱装置５０によって粒子流路３３内の気体を加熱することによって、筐体３０（粒子流路３３）内に測定対象の気体（大気）を容易に引き込むことができるので、加熱装置５０を設けない場合と比べて、粒子検出センサ１内に多くの粒子を取り込むことができる。したがって、粒子流路３３に含まれる検知領域ＤＡにおける単位体積あたりの粒子数を多くすることができるので、感度を高くすることができる。 Thus, by heating the gas in the particle channel 33 by the heating device 50, the gas (atmosphere) to be measured can be easily drawn into the housing 30 (particle channel 33). Compared with the case where 50 is not provided, more particles can be taken into the particle detection sensor 1. Therefore, since the number of particles per unit volume in the detection area DA included in the particle flow path 33 can be increased, the sensitivity can be increased.
　なお、加熱装置５０が動作していない状態でも、大気導入孔３５と大気排出孔３６との間において気体は粒子流路３３内を通過することができる。つまり、加熱装置５０が動作していない場合でも、気体中に含まれる粒子を検出することは可能である。 Even when the heating device 50 is not operating, the gas can pass through the particle flow path 33 between the air introduction hole 35 and the air discharge hole 36. That is, even when the heating device 50 is not operating, it is possible to detect particles contained in the gas.
　次に、本実施の形態における粒子検出センサ１の動作について、図２Ａ、図２Ｂ及び図２Ｃを用いて説明する。図２Ａ～図２Ｃは、それぞれ、気体中に粒子が存在しない場合、気体中に粒径の小さい粒子が存在する場合及び気体中に粒径の大きい粒子が存在する場合における粒子検出センサ１の動作を説明するための断面図である。 Next, the operation of the particle detection sensor 1 according to the present embodiment will be described with reference to FIGS. 2A, 2B, and 2C. 2A to 2C show the operation of the particle detection sensor 1 when there is no particle in the gas, when there is a particle with a small particle size in the gas, and when there is a particle with a large particle size in the gas, respectively. It is sectional drawing for demonstrating.
　加熱装置５０を動作させて粒子流路３３に気流を発生させると、大気導入孔３５から粒子検出センサ１内に気体が引き込まれ、当該気体は、粒子流路３３を経由して検知領域ＤＡに導かれる。 When the heating device 50 is operated to generate an air flow in the particle passage 33, gas is drawn into the particle detection sensor 1 from the atmosphere introduction hole 35, and the gas passes through the particle passage 33 and enters the detection area DA. Led.
　この場合、図２Ａに示すように、粒子検出センサ１内に導入された気体に粒子（エアロゾル）が存在しない場合、つまり、検知領域ＤＡに粒子が流入しない場合は、投光素子１０から出射した光は検知領域ＤＡを通過してそのまま直進するので、粒子による散乱光が発生しない。したがって、この場合、基本的には受光素子２０の反応がないので、粒子検出センサ１内に導入された気体中に粒子が存在しないことが分かる。 In this case, as shown in FIG. 2A, when there is no particle (aerosol) in the gas introduced into the particle detection sensor 1, that is, when the particle does not flow into the detection area DA, it is emitted from the light projecting element 10. Since the light passes straight through the detection area DA, light scattered by particles is not generated. Therefore, in this case, basically, there is no reaction of the light receiving element 20, so that it can be seen that there are no particles in the gas introduced into the particle detection sensor 1.
　なお、この場合、検知領域ＤＡを通過して直進した光が筐体３０の中で反射して迷光となって受光素子２０に入射する場合があるが、受光素子２０で検出される光強度は、検知領域ＤＡに粒子が存在する場合と比べて小さい。したがって、粒子検出センサ１内に導入された大気中に粒子が存在しないことが分かる。また、本実施の形態では、トラップ部３４が設けられているので、検知領域ＤＡを通過して直進した光は、トラップ部３４で減衰吸収される。これにより、検知領域ＤＡを通過して直進した光が迷光となって受光素子２０に入射することを抑制できる。 In this case, light that has traveled straight after passing through the detection area DA may be reflected in the housing 30 and enter the light receiving element 20 as stray light. However, the light intensity detected by the light receiving element 20 is This is smaller than when particles are present in the detection area DA. Therefore, it can be seen that there are no particles in the atmosphere introduced into the particle detection sensor 1. In the present embodiment, since the trap part 34 is provided, the light that has traveled straight through the detection area DA is attenuated and absorbed by the trap part 34. As a result, it is possible to prevent light that has traveled straight through the detection area DA from entering the light receiving element 20 as stray light.
　また、図２Ｂに示すように、粒子検出センサ１内に導入した気体に粒径の小さい粒子（エアロゾル）Ｐ１が存在する場合、つまり、検知領域ＤＡに粒径の小さい粒子Ｐ１が流入した場合は、投光素子１０の光は検知領域ＤＡに存在する粒子Ｐ１に当たって散乱し、当該散乱光は直接又は反射体４０で反射して受光素子２０に入射する。受光素子２０に光が入射すると所定の信号の出力があるので、粒子検出センサ１内に導入された気体中に粒子が存在することが分かる。 In addition, as shown in FIG. 2B, when the particle (aerosol) P1 having a small particle diameter exists in the gas introduced into the particle detection sensor 1, that is, when the particle P1 having a small particle diameter flows into the detection area DA. The light of the light projecting element 10 strikes the particle P1 existing in the detection area DA and is scattered, and the scattered light is reflected directly or by the reflector 40 and enters the light receiving element 20. When light enters the light receiving element 20, there is an output of a predetermined signal, so that it can be seen that particles are present in the gas introduced into the particle detection sensor 1.
　この場合、受光素子２０によって検出される散乱光の光強度は比較的に小さいので、粒子検出センサ１内に導入した気体中には粒径の小さい粒子が存在することが分かる。 In this case, since the light intensity of the scattered light detected by the light receiving element 20 is relatively small, it can be seen that particles having a small particle diameter exist in the gas introduced into the particle detection sensor 1.
　また、図２Ｃに示すように、粒子検出センサ１内に導入した気体に粒径の大きい粒子（エアロゾル）Ｐ２が存在する場合、つまり、検知領域ＤＡに粒径の大きい粒子Ｐ２が流入した場合も、投光素子１０の光は検知領域ＤＡに存在する粒子Ｐ２に当たって散乱し、当該散乱光は直接又は反射体４０で反射して受光素子２０に入射する。受光素子２０に光が入射すると所定の信号の出力があるので、この場合も、粒子検出センサ１内に導入された気体中に粒子が存在することが分かる。 In addition, as shown in FIG. 2C, when a particle (aerosol) P2 having a large particle diameter exists in the gas introduced into the particle detection sensor 1, that is, when a particle P2 having a large particle diameter flows into the detection area DA. The light of the light projecting element 10 strikes the particles P2 existing in the detection area DA and is scattered, and the scattered light is reflected directly or by the reflector 40 and enters the light receiving element 20. When light enters the light receiving element 20, there is an output of a predetermined signal. In this case as well, it can be seen that particles are present in the gas introduced into the particle detection sensor 1.
　この場合、受光素子２０によって検出される散乱光の光強度は比較的に大きいので、粒子検出センサ１内に導入した気体中には粒径の大きい粒子Ｐ２が存在することが分かる。 In this case, since the light intensity of the scattered light detected by the light receiving element 20 is relatively high, it can be seen that particles P2 having a large particle size exist in the gas introduced into the particle detection sensor 1.
　このように、粒子による散乱光によって粒子検出センサ１内に導入された気体に粒子が含まれるか否か（粒子の有無）を検知することができる。つまり、気体中の粒子を検出することができる。 Thus, it is possible to detect whether or not particles are contained in the gas introduced into the particle detection sensor 1 by the scattered light from the particles (the presence or absence of particles). That is, particles in the gas can be detected.
　また、受光素子２０で受光した信号の大きさ、つまり、粒子による散乱光の光強度の大きさによって、粒子の大きさ（粒径）を判別することができる。 Further, the size (particle size) of the particle can be determined based on the size of the signal received by the light receiving element 20, that is, the light intensity of the scattered light from the particle.
　さらに、受光素子２０で検出される信号の出力の１つ１つ、つまり、粒子による散乱光の光強度のピーク１つ１つは、粒子の１つ１つに対応するので、粒子検出センサ１内に導入された気体の中の粒子の個数（量）も算出することができる。 Further, each output of the signal detected by the light receiving element 20, that is, each peak of the light intensity of the scattered light by the particles corresponds to each of the particles, so that the particle detection sensor 1. The number (amount) of particles in the gas introduced into the gas can also be calculated.
　次に、本実施の形態における粒子検出センサ１の作用効果について、比較例１の粒子検出センサ１００と比較しながら、図３及び図４を用いて説明する。図３は、比較例１の粒子検出センサ１００の断面図であり、図４は、実施の形態１に係る粒子検出センサ１の断面図である。 Next, the operational effects of the particle detection sensor 1 according to the present embodiment will be described with reference to FIGS. 3 and 4 while comparing with the particle detection sensor 100 of Comparative Example 1. FIG. FIG. 3 is a cross-sectional view of the particle detection sensor 100 of Comparative Example 1, and FIG. 4 is a cross-sectional view of the particle detection sensor 1 according to the first embodiment.
　図３に示すように、比較例１の粒子検出センサ１００では、受光領域３２に反射体が設けられておらず、受光レンズ（集光レンズ）１４０が設けられている。これにより、受光レンズ１４０による制約が大きくなり、例えば、受光レンズ１４０の光軸と受光素子２０の光軸とを一致させる必要がある。また、受光レンズ１４０の形状も、その機能から変更できる自由度が小さく、例えば、レンズ光軸に対して対称形状となっている。これらのことから、図３に示すように、受光レンズ１４０を用いた場合では、検知領域ＤＡを基準とする受光レンズ１４０への見込み角が小さくなる。 As shown in FIG. 3, in the particle detection sensor 100 of Comparative Example 1, the light receiving region 32 is not provided with a reflector, and a light receiving lens (condensing lens) 140 is provided. Thereby, restrictions by the light receiving lens 140 increase, and for example, it is necessary to make the optical axis of the light receiving lens 140 coincide with the optical axis of the light receiving element 20. Also, the shape of the light receiving lens 140 has a small degree of freedom that can be changed due to its function, and is, for example, symmetrical with respect to the lens optical axis. For these reasons, as shown in FIG. 3, when the light receiving lens 140 is used, the expected angle to the light receiving lens 140 with reference to the detection area DA is reduced.
　しかも、レンズによる集光では、そもそも原理的に１８０°以上の光を取ることができず、また、様々な方向からの散乱光も取ることができない。さらに、レンズの焦点が検知領域ＤＡとなるので、検知領域ＤＡは小さい。 Moreover, in the first place, the light collected by the lens cannot take light of 180 ° or more, and it cannot take scattered light from various directions. Furthermore, since the focal point of the lens is the detection area DA, the detection area DA is small.
　したがって、受光レンズ１４０のみで散乱光を集光する比較例１の粒子検出センサ１００では、散乱光の受光感度が低い。 Therefore, in the particle detection sensor 100 of Comparative Example 1 that collects scattered light only by the light receiving lens 140, the light receiving sensitivity of the scattered light is low.
　特に、気体中に浮遊する粒子には、ＰＭ２．５（微小粒子状物質）等の粒径の小さな微粒子も存在する。このような微粒子を検出するには、粒子検出センサとしては、例えば粒径が０．３μｍ以下の粒子を検出できる精度が要求される。 Especially, particles having a small particle diameter such as PM2.5 (microparticulate matter) are also present in the particles floating in the gas. In order to detect such fine particles, the particle detection sensor is required to have an accuracy capable of detecting particles having a particle size of 0.3 μm or less, for example.
　粒子検出センサの粒子検出精度を向上させるには、例えば、ファンを設けることが考えられる。つまり、ファンによって粒子の流れを速くし、単位時間当たりに粒子検出センサ内に入る粒子の量を増やすことで、粒径の小さな微粒子の検出精度を向上させることが考えられる。 In order to improve the particle detection accuracy of the particle detection sensor, for example, a fan may be provided. That is, it is conceivable to improve the detection accuracy of fine particles having a small particle size by increasing the amount of particles entering the particle detection sensor per unit time by increasing the flow of particles by a fan.
　しかしながら、ファンを設けると、粒子検出センサ全体のコストが高くなったり粒子検出センサが大型化したりする。 However, if a fan is provided, the cost of the entire particle detection sensor increases or the particle detection sensor becomes larger.
　一方、ファンを設けるのではなく、低コストかつ省スペースであるヒータ抵抗等の加熱装置を設けることによって気流を発生させることも考えられる。 On the other hand, instead of providing a fan, it may be possible to generate an air flow by providing a heating device such as a heater resistor that is low-cost and space-saving.
　しかしながら、加熱装置の場合では、ファンの場合と比べて流速が遅く、それほど検出精度を高くすることができない。このため、ＰＭ２．５等の粒径の小さな微粒子を精度よく検出することができない。 However, in the case of a heating device, the flow rate is slower than in the case of a fan, and the detection accuracy cannot be increased so much. For this reason, fine particles having a small particle diameter such as PM2.5 cannot be detected with high accuracy.
　これに対して、本実施の形態における粒子検出センサ１は、図４に示すように、検知領域ＤＡにおける粒子による散乱光を反射して当該散乱光を受光素子２０に導くための反射体４０を有している。 On the other hand, the particle detection sensor 1 in the present embodiment includes a reflector 40 for reflecting scattered light from particles in the detection area DA and guiding the scattered light to the light receiving element 20 as shown in FIG. Have.
　これにより、レンズの場合と比べて、検知領域ＤＡの粒子によって発生する散乱光を、より多く受光素子２０に入射させることが可能となる。つまり、反射体４０は、レンズと比べて設計自由度が大きいので、より多くの散乱光を受光素子２０に導けるように形状を決めることができる。 This makes it possible to make more scattered light generated by the particles in the detection area DA incident on the light receiving element 20 than in the case of the lens. That is, the reflector 40 has a greater degree of design freedom than the lens, and thus can be shaped so that more scattered light can be guided to the light receiving element 20.
　例えば、図４に示すように、反射体４０の開口部を受光領域３２の開口部のぎりぎりまで延ばすことができ、検知領域ＤＡを基準とする反射体４０への見込み角を大きくすることができる。また、反射体４０の光軸（受光素子２０の光軸）に対して見込み角を対称にすることなく反射体４０の形状を決めることもできるので、反射体４０の形状を自由に変更することができる。 For example, as shown in FIG. 4, the opening of the reflector 40 can be extended to the limit of the opening of the light receiving region 32, and the expected angle to the reflector 40 based on the detection region DA can be increased. . Moreover, since the shape of the reflector 40 can be determined without making the prospective angle symmetric with respect to the optical axis of the reflector 40 (the optical axis of the light receiving element 20), the shape of the reflector 40 can be freely changed. Can do.
　このように、本実施の形態における粒子検出センサ１では、図３に示す比較例１と比べて、散乱光を集める立体角を大きくすることができるので散乱光の受光感度を高くすることが可能となり、検知領域ＤＡを大きくすることができる。 As described above, in the particle detection sensor 1 according to the present embodiment, the solid angle for collecting scattered light can be increased as compared with the comparative example 1 shown in FIG. 3, so that the light receiving sensitivity of the scattered light can be increased. Thus, the detection area DA can be enlarged.
　このため、気流がゆっくりであっても、粒子は検出領域ＤＡを通過しやすくなる。特に、粒径の小さな粒子の場合、図３に示す比較例１では、検出領域ＤＡを通過する粒子の確率は小さいが、図４に示す本実施の形態では、検出領域ＤＡを通過する粒子の確率が格段に向上し、受光感度も高くなる。したがって、粒径の小さな微粒子を精度よく検出することができる。 Therefore, even if the airflow is slow, the particles easily pass through the detection area DA. In particular, in the case of particles having a small particle diameter, the probability of particles passing through the detection area DA is small in Comparative Example 1 shown in FIG. 3, but in the present embodiment shown in FIG. Probability is greatly improved, and light receiving sensitivity is also increased. Therefore, fine particles having a small particle diameter can be detected with high accuracy.
　以上、本実施の形態に係る粒子検出センサ１は、反射体４０を備えているので、受光領域３２にレンズを設ける場合と比べて受光感度を高くすることができる。これにより、ヒータ抵抗等の加熱装置５０によって生じさせることのできる程度の気流であったとしても、気体中に含まれる粒径の小さな粒子を高精度で検出することができる。したがって、加熱装置５０を用いた加熱方式の粒子検出センサであっても、気体中に含まれる粒子が、ホコリであるか、花粉であるか、煙であるかを判別できるだけではなく、ＰＭ２．５（微小粒子状物質）のように粒径の小さな微粒子までも判別することができる。 As mentioned above, since the particle | grain detection sensor 1 which concerns on this Embodiment is provided with the reflector 40, compared with the case where a lens is provided in the light reception area | region 32, it can make light reception sensitivity high. Thereby, even if it is the airflow of the grade which can be generated with the heating apparatuses 50, such as heater resistance, the particle | grains with a small particle diameter contained in gas can be detected with high precision. Therefore, even in a heating type particle detection sensor using the heating device 50, not only can the particle contained in the gas be dust, pollen, or smoke, but also PM2.5. Even fine particles having a small particle diameter such as (microparticulate matter) can be distinguished.
　このように、本実施の形態に係る粒子検出センサ１によれば、低コストかつ小型でありながら、高精度の粒子検出センサを実現することができる。 Thus, according to the particle detection sensor 1 according to the present embodiment, a highly accurate particle detection sensor can be realized while being low-cost and small.
　さらに、本実施の形態では、反射体４０の内面が回転楕円体の回転面の一部をなしている。これにより、検知領域ＤＡの粒子によって発生する散乱光の多くを受光素子２０に入射させることができるので、感度を一層高くすることができる。 Furthermore, in the present embodiment, the inner surface of the reflector 40 forms a part of the rotational surface of the spheroid. Thereby, most of the scattered light generated by the particles in the detection area DA can be incident on the light receiving element 20, so that the sensitivity can be further increased.
　ここで、反射体４０について、当該反射体４０と受光素子２０と検知領域ＤＡとの位置関係及びその作用効果について、図５を用いて詳細に説明する。図５は、実施の形態１に係る粒子検出センサ１における反射体４０と受光素子２０と検知領域ＤＡとの位置関係を説明するための図である。 Here, with respect to the reflector 40, the positional relationship among the reflector 40, the light receiving element 20, and the detection area DA and the function and effect thereof will be described in detail with reference to FIG. FIG. 5 is a diagram for explaining the positional relationship among the reflector 40, the light receiving element 20, and the detection area DA in the particle detection sensor 1 according to the first embodiment.
　図５に示すように、本実施の形態における反射体４０は、内面が回転楕円体の回転面の一部をなしており、反射体４０の内面の断面形状は、楕円の一部となっている。そして、反射体４０は、回転楕円体を構成する楕円における２つの焦点Ｆ１及びＦ２のうちの一方の焦点Ｆ１（第１の焦点）が検知領域ＤＡ内に存在するように配置されている。また、受光素子２０は、当該楕円における他方の焦点Ｆ２（第２の焦点）近傍に配置されている。 As shown in FIG. 5, the reflector 40 in the present embodiment has an inner surface that forms part of the rotational surface of the spheroid, and the cross-sectional shape of the inner surface of the reflector 40 is part of the ellipse. Yes. The reflector 40 is arranged such that one of the two focal points F1 and F2 (first focal point) in the ellipse constituting the spheroid exists in the detection area DA. The light receiving element 20 is disposed in the vicinity of the other focal point F2 (second focal point) of the ellipse.
　これにより、検知領域ＤＡの粒子によって発生する散乱光を、少ない反射回数（１回又は数回）で受光素子２０に入射させることができる。つまり、多重反射による光の減衰を回避できる。したがって、受光素子２０における受光効率を高めることができるので、感度を一層高くすることができる。 Thereby, the scattered light generated by the particles in the detection area DA can be incident on the light receiving element 20 with a small number of reflections (one or several times). That is, attenuation of light due to multiple reflection can be avoided. Therefore, since the light receiving efficiency in the light receiving element 20 can be increased, the sensitivity can be further increased.
　さらに、受光素子２０における受光効率を高くできることから、受光素子２０として小型の検出器等を用いることができる。つまり、受光素子２０として、特段受光面の大きい光検出器を用いる必要がない。 Furthermore, since the light receiving efficiency of the light receiving element 20 can be increased, a small detector or the like can be used as the light receiving element 20. That is, it is not necessary to use a photodetector having a particularly large light receiving surface as the light receiving element 20.
　しかも、本実施の形態における粒子検出センサ１によれば、ヒータ加熱により大気を導入するヒータ方式が採用されているので、簡単で低コストのセンサを実現できる。 In addition, according to the particle detection sensor 1 of the present embodiment, a heater system that introduces the atmosphere by heating the heater is employed, so that a simple and low-cost sensor can be realized.
　（実施の形態２）
　次に、実施の形態２に係る粒子検出センサ２の構成について、図６を用いて説明する。図６は、実施の形態２に係る粒子検出センサ２の構成を示す図であり、（ａ）は上面図、（ｂ）は正面図、（ｃ）は下面図、（ｄ）は（ａ）のＡ－Ａ線における断面図である。なお、本実施の形態でも、図６（ｄ）における大気排出孔３６から大気導入孔３５に向かう方向を鉛直下方（重力方向）としている。 (Embodiment 2)
Next, the configuration of the particle detection sensor 2 according to Embodiment 2 will be described with reference to FIG. 6A and 6B are diagrams showing the configuration of the particle detection sensor 2 according to Embodiment 2, wherein FIG. 6A is a top view, FIG. 6B is a front view, FIG. 6C is a bottom view, and FIG. It is sectional drawing in the AA of FIG. Also in this embodiment, the direction from the air discharge hole 36 to the air introduction hole 35 in FIG.
　図６に示すように、本実施の形態における粒子検出センサ２は、実施の形態１における粒子検出センサ１と同様に、投光素子１０と受光素子２０とを備える光電式センサであって、検知領域（光散乱部）ＤＡにおける粒子による投光素子１０からの光の散乱光を受光素子２０で受光することにより大気中に含まれる粒子を検出するものである。 As shown in FIG. 6, the particle detection sensor 2 in the present embodiment is a photoelectric sensor that includes a light projecting element 10 and a light receiving element 20 in the same manner as the particle detection sensor 1 in the first embodiment. The light contained in the atmosphere is detected by receiving the scattered light of the light from the light projecting element 10 by the particles in the region (light scattering part) DA by the light receiving element 20.
　本実施の形態における粒子検出センサ２は、さらに、筐体３０と、筐体３０内に配置された、反射体４０、加熱装置５０、第１遮光体６１、第２遮光体６２、投光絞り部７１、投光反対絞り部７２、受光反対絞り部７３、第１保護板８１及び第２保護板８２とを備える。 The particle detection sensor 2 according to the present embodiment further includes a housing 30, and a reflector 40, a heating device 50, a first light shielding body 61, a second light shielding body 62, and a light projection diaphragm disposed in the housing 30. Unit 71, a light projection counter diaphragm unit 72, a light reception counter diaphragm unit 73, a first protection plate 81, and a second protection plate 82.
　本実施の形態でも、投光素子１０及び受光素子２０の各々の光軸を交差させているが、本実施の形態では、投光素子１０の光軸と受光素子２０の光軸とのなす角は１２０度（６０度）にしている。 Also in the present embodiment, the optical axes of the light projecting element 10 and the light receiving element 20 are crossed. In the present embodiment, the angle formed by the optical axis of the light projecting element 10 and the optical axis of the light receiving element 20. Is 120 degrees (60 degrees).
　本実施の形態において、筐体３０には、投光領域３１と、受光領域３２と、粒子流路３３と、投光トラップ部３４ａ（第１トラップ部）と、受光トラップ部３４ｂ（第２トラップ部）とが設けられている。 In the present embodiment, the housing 30 includes a light projecting region 31, a light receiving region 32, a particle channel 33, a light projecting trap unit 34a (first trap unit), and a light receiving trap unit 34b (second trap). Part).
　投光領域３１、受光領域３２、粒子流路３３、投光トラップ部３４ａ及び受光トラップ部３４ｂの各々は、周囲が筐体３０の内面（内壁）で囲まれた空間領域であり、粒子流路３３との接続部分に開口部を有している。投光領域３１、受光領域３２、投光トラップ部３４ａ及び受光トラップ部３４ｂの各々の開口部は、検知領域ＤＡに向かって開口している。 Each of the light projecting area 31, the light receiving area 32, the particle flow path 33, the light projecting trap section 34a, and the light receiving trap section 34b is a space area surrounded by the inner surface (inner wall) of the housing 30. 33 has an opening at the connection portion. Each opening part of the light projection area | region 31, the light reception area | region 32, the light projection trap part 34a, and the light reception trap part 34b is opened toward the detection area DA.
　投光領域３１、受光領域３２、粒子流路３３、投光トラップ部３４ａ及び受光トラップ部３４ｂにおける筐体３０の内面（壁面）は、迷光を吸収させるために黒色であるとよい。例えば、筐体３０を黒色の樹脂成型品にすることで、筐体３０の内面を黒色面にすることができる。 The inner surface (wall surface) of the housing 30 in the light projecting region 31, the light receiving region 32, the particle flow path 33, the light projecting trap unit 34a, and the light receiving trap unit 34b may be black in order to absorb stray light. For example, the inner surface of the housing 30 can be made a black surface by making the housing 30 a black resin molded product.
　本実施の形態において、投光領域３１には、投光絞り部（発光絞り部）７１が設けられている。投光絞り部７１（第１絞り部）は、投光レンズ３１ａを通過した後の光を絞って不要な光を遮蔽して集光径を小さくする。投光絞り部７１を設けることによって迷光を防ぐことができ、粒子の検出精度を向上させることができる。 In the present embodiment, the light projection area 31 is provided with a light projection diaphragm section (light emission diaphragm section) 71. The light projection aperture 71 (first aperture) narrows the light after passing through the light projection lens 31a to shield unnecessary light and reduce the light collection diameter. By providing the light projection aperture 71, stray light can be prevented, and the particle detection accuracy can be improved.
　投光絞り部７１は、各々が円形や多角形などの開口（スリット）を有する複数の光学絞りからなる。本実施の形態において、投光絞り部７１（光学絞り）は、投光領域３１の内壁から突出するように形成されている。投光絞り部７１（光学絞り）は、樹脂等からなり、筐体３０と一体成型されていてもよいし、筐体３０と別体であってもよい。 The light projection aperture 71 is composed of a plurality of optical apertures each having a circular or polygonal opening (slit). In the present embodiment, the light projection diaphragm 71 (optical diaphragm) is formed so as to protrude from the inner wall of the light projection area 31. The light projection aperture 71 (optical aperture) is made of resin or the like, and may be integrally formed with the housing 30 or may be separate from the housing 30.
　また、投光絞り部７１における光学絞りの開口の端部（端面）は、当該光学絞りの光軸を含む断面において２つの直線によって鋭角をなしており、当該２つの直線の一方を含む面（平面又は曲面等）は、入射する光を検知領域ＤＡ以外の方向に反射させる反射面である。これにより、迷光を防ぐことができるので、粒子の検出精度を向上させることができる。 In addition, an end (end surface) of the aperture of the optical diaphragm in the light projection diaphragm 71 forms an acute angle with two straight lines in a cross section including the optical axis of the optical diaphragm, and includes a surface including one of the two straight lines ( Flat surface or curved surface) is a reflecting surface that reflects incident light in a direction other than the detection area DA. Thereby, since stray light can be prevented, the detection accuracy of particles can be improved.
　投光トラップ部３４ａ及び受光トラップ部３４ｂは、光トラップ構造を有しており、投光トラップ部３４ａ及び受光トラップ部３４ｂの内部に一旦進入した光が投光トラップ部３４ａ及び受光トラップ部３４ｂから出て行かないような光吸収構造を有する。投光トラップ部３４ａ及び受光トラップ部３４ｂは、例えば、投光トラップ部３４ａ及び受光トラップ部３４ｂの内部に進入した光を多重反射させて吸収する。投光トラップ部３４ａ及び受光トラップ部３４ｂを設けることによって、筐体３０内の迷光を吸収することができる。これにより、粒子の検出精度を向上させることができる。なお、投光トラップ部３４ａ及び受光トラップ部３４ｂは、ラビリンス構造であってもよい。 The light projecting trap unit 34a and the light receiving trap unit 34b have an optical trap structure, and light that has once entered the light projecting trap unit 34a and the light receiving trap unit 34b is transmitted from the light projecting trap unit 34a and the light receiving trap unit 34b. It has a light absorption structure that does not go out. The light projecting trap unit 34a and the light receiving trap unit 34b, for example, absorb and multi-reflect light that has entered the light projecting trap unit 34a and the light receiving trap unit 34b. By providing the light projecting trap part 34a and the light receiving trap part 34b, stray light in the housing 30 can be absorbed. Thereby, the detection accuracy of particles can be improved. The light projecting trap part 34a and the light receiving trap part 34b may have a labyrinth structure.
　具体的には、投光トラップ部３４ａは、投光素子１０から出射する光のうち検知領域ＤＡで粒子に当たらずに検知領域ＤＡを通過した光が筐体３０内で反射及び散乱して受光素子２０で受光されてしまうことを防止する構造を有する。投光トラップ部３４ａは、検知領域ＤＡを挟んで投光素子１０と対向する位置に設けられている。 Specifically, the light projecting trap part 34a receives and reflects and scatters light that has passed through the detection area DA without hitting the particles in the detection area DA out of the light emitted from the light projecting element 10. It has a structure that prevents the element 20 from receiving light. The light projecting trap part 34a is provided at a position facing the light projecting element 10 across the detection area DA.
　投光トラップ部３４ａには、投光反対絞り部７２（第２絞り部）が設けられている。つまり、投光反対絞り部７２は、検知領域ＤＡを挟んで投光素子１０の反対側に設けられている。投光反対絞り部７２を設けることによって迷光を防ぐことができ、粒子の検出精度を向上させることができる。 The projection trap part 34a is provided with a projection opposite diaphragm part 72 (second diaphragm part). That is, the light projection opposite diaphragm portion 72 is provided on the opposite side of the light projecting element 10 with the detection area DA interposed therebetween. By providing the light projection opposite stop portion 72, stray light can be prevented and particle detection accuracy can be improved.
　投光反対絞り部７２は、各々が円形や多角形などの開口（スリット）を有する複数の光学絞りからなる。本実施の形態において、投光反対絞り部７２（光学絞り）は、投光トラップ部３４ａの内壁から突出するように形成されている。投光反対絞り部７２（光学絞り）は、樹脂等からなり、筐体３０と一体成型されていてもよいし、筐体３０と別体であってもよい。 The light projection opposite stop 72 includes a plurality of optical stops each having an opening (slit) such as a circle or a polygon. In the present embodiment, the light projection opposite diaphragm portion 72 (optical diaphragm) is formed so as to protrude from the inner wall of the light projection trap portion 34a. The light projection opposite diaphragm portion 72 (optical diaphragm) is made of resin or the like, and may be integrally formed with the housing 30 or may be separate from the housing 30.
　また、投光反対絞り部７２における光学絞りの開口の端部（端面）は、２つの平面によって鋭角をなしており、当該２つの平面の一方の面は、入射する光を検知領域ＤＡ以外の方向に反射させる反射面である。つまり、投光反対絞り部７２における光学絞りの開口の端部（端面）は、当該光学絞りの光軸を含む断面において２つの直線によって鋭角をなしており、当該２つの直線の一方を含む面（平面又は曲面等）は、入射する光を検知領域ＤＡ以外の方向に反射させる反射面である。これにより、迷光を防ぐことができるので、粒子の検出精度を向上させることができる。 Further, the end (end face) of the aperture of the optical stop in the light projection opposite stop portion 72 forms an acute angle by two planes, and one surface of the two planes transmits incident light other than the detection area DA. It is a reflective surface that reflects in the direction. That is, the end (end surface) of the aperture of the optical aperture in the light projection opposite aperture section 72 forms an acute angle with two straight lines in a cross section including the optical axis of the optical aperture, and includes one of the two straight lines. (Plane or curved surface) is a reflecting surface that reflects incident light in a direction other than the detection area DA. Thereby, since stray light can be prevented, the detection accuracy of particles can be improved.
　本実施の形態において、投光トラップ部３４ａにおける投光反対絞り部７２の奥側には、光を検知領域ＤＡ側とは反対側に導く曲面が形成されている。これにより、投光トラップ部３４ａの内部に一旦進入した光を、投光トラップ部３４ａから出て行きにくくすることができる。この結果、迷光を防ぐことができるので、粒子の検出精度を向上させることができる。 In the present embodiment, a curved surface that guides light to the side opposite to the detection area DA side is formed on the back side of the light projection opposite diaphragm portion 72 in the light projection trap portion 34a. Thereby, it is possible to make it difficult for the light once entering the inside of the light projecting trap part 34a to go out of the light projecting trap part 34a. As a result, stray light can be prevented, so that the particle detection accuracy can be improved.
　一方、受光トラップ部３４ｂは、検知領域ＤＡにおける粒子の散乱光のうち受光素子２０（受光領域３２）とは反対側に進行する光が筐体３０内で反射及び散乱して受光素子２０で受光されてしまうことを防止する構造を有する。受光トラップ部３４ｂは、検知領域ＤＡを挟んで受光素子２０と対向する位置に設けられている。 On the other hand, the light receiving trap part 34b reflects and scatters the light traveling on the opposite side to the light receiving element 20 (light receiving area 32) among the scattered light of the particles in the detection area DA and receives it by the light receiving element 20. It has a structure which prevents it being done. The light receiving trap part 34b is provided at a position facing the light receiving element 20 across the detection area DA.
　受光トラップ部３４ｂには、受光反対絞り部７３（第３絞り部）が設けられている。つまり、受光反対絞り部７３は、検知領域ＤＡを挟んで受光素子２０の反対側に設けられている。受光反対絞り部７３を設けることによって迷光を防ぐことができ、粒子の検出精度を向上させることができる。 The light receiving trap portion 34b is provided with a light receiving opposite stop portion 73 (third stop portion). In other words, the light receiving opposite diaphragm portion 73 is provided on the opposite side of the light receiving element 20 with the detection area DA interposed therebetween. By providing the stop portion 73 opposite to the light reception, stray light can be prevented, and the particle detection accuracy can be improved.
　受光反対絞り部７３は、投光反対絞り部７２と同様に、各々が円形や多角形などの開口（スリット）を有する複数の光学絞りからなる。本実施の形態において、受光反対絞り部７３（光学絞り）は、受光トラップ部３４ｂの内壁から突出するように形成されている。受光反対絞り部７３（光学絞り）は、樹脂等からなり、筐体３０と一体成型されていてもよいし、筐体３０と別体であってもよい。 Similarly to the light projection counter diaphragm section 72, the light reception counter diaphragm section 73 is composed of a plurality of optical diaphragms each having an opening (slit) such as a circle or a polygon. In the present embodiment, the light receiving opposite stop portion 73 (optical stop) is formed so as to protrude from the inner wall of the light receiving trap portion 34b. The light receiving opposite diaphragm 73 (optical diaphragm) is made of resin or the like, and may be integrally formed with the housing 30 or may be separate from the housing 30.
　また、受光反対絞り部７３における光学絞りの開口の端部（端面）は、当該光学絞りの光軸を含む断面において２つの直線によって鋭角をなしており、当該２つの直線の一方を含む面（曲面又は平面等）は、入射する光を検知領域ＤＡ以外の方向に反射させる反射面である。これにより、迷光を防ぐことができるので、粒子の検出精度を向上させることができる。 In addition, the end (end surface) of the aperture of the optical diaphragm in the opposite light receiving diaphragm 73 forms an acute angle with two straight lines in a cross section including the optical axis of the optical diaphragm, and includes a surface including one of the two straight lines ( A curved surface or a flat surface is a reflecting surface that reflects incident light in a direction other than the detection area DA. Thereby, since stray light can be prevented, the detection accuracy of particles can be improved.
　本実施の形態において、受光トラップ部３４ｂにおける受光反対絞り部７３の奥側には、光を検知領域ＤＡ側とは反対側に導く曲面が形成されている。これにより、受光トラップ部３４ｂの内部に一旦進入した光を、受光トラップ部３４ｂから出て行きにくくすることができる。この結果、迷光を防ぐことができるので、粒子の検出精度を向上させることができる。 In the present embodiment, a curved surface that guides light to the side opposite to the detection area DA side is formed on the back side of the light receiving opposite diaphragm portion 73 in the light receiving trap portion 34b. Thereby, it is possible to make it difficult for the light once entering the inside of the light receiving trap part 34b to go out of the light receiving trap part 34b. As a result, stray light can be prevented, so that the particle detection accuracy can be improved.
　本実施の形態でも、受光領域３２には反射体４０が配置されている。反射体４０によって、検知領域ＤＡにおける粒子の散乱光が受光素子２０に導かれる。なお、本実施の形態では、反射体４０の開口部側の端部が第１保護板８１に接触している。 Also in the present embodiment, the reflector 40 is disposed in the light receiving region 32. The scattered light of the particles in the detection area DA is guided to the light receiving element 20 by the reflector 40. In the present embodiment, the end of the reflector 40 on the opening side is in contact with the first protective plate 81.
　ここで、本実施の形態における粒子検出センサ２において、反射体４０と投光素子１０と受光素子２０と検知領域ＤＡとの位置関係及びその光学作用について、図７を用いて詳細に説明する。図７は、実施の形態２に係る粒子検出センサ２における反射体４０と投光素子１０と受光素子２０と検知領域ＤＡとの位置関係を示す図である。 Here, in the particle detection sensor 2 in the present embodiment, the positional relationship among the reflector 40, the light projecting element 10, the light receiving element 20, and the detection area DA and the optical action thereof will be described in detail with reference to FIG. FIG. 7 is a diagram showing a positional relationship among the reflector 40, the light projecting element 10, the light receiving element 20, and the detection area DA in the particle detection sensor 2 according to the second embodiment.
　図７に示すように、本実施の形態における反射体４０も、楕円ミラーとなっており、回転楕円体によって構成されている。また、実施の形態１と同様に、反射体４０は、当該回転楕円体を構成する楕円における２つの焦点Ｆ１及びＦ２のうちの一方の焦点Ｆ１（第１の焦点）が検知領域ＤＡ内に存在するように、かつ、他方の焦点Ｆ２（第２の焦点）が受光素子２０の近傍に存在するように配置されている。つまり、受光素子２０は、当該楕円における焦点Ｆ２の近傍に配置されている。 As shown in FIG. 7, the reflector 40 in the present embodiment is also an elliptical mirror, and is constituted by a spheroid. Similarly to the first embodiment, the reflector 40 has one focal point F1 (first focal point) of the two focal points F1 and F2 in the ellipse constituting the spheroid in the detection area DA. And the other focal point F2 (second focal point) is arranged in the vicinity of the light receiving element 20. That is, the light receiving element 20 is disposed in the vicinity of the focal point F2 in the ellipse.
　このように、焦点Ｆ１を検知領域ＤＡに対応させるとともに焦点Ｆ２を受光素子２０に対応させることによって、検知領域ＤＡの粒子によって発生する散乱光を、少ない反射回数（１回又は数回）で受光素子２０に入射させることができる。つまり、多重反射による光の減衰を回避できる。したがって、受光素子２０における受光効率を高めることができる。 In this way, by making the focal point F1 correspond to the detection area DA and the focal point F2 correspond to the light receiving element 20, the scattered light generated by the particles in the detection area DA is received with a small number of reflections (one or several times). The light can enter the element 20. That is, attenuation of light due to multiple reflection can be avoided. Therefore, the light receiving efficiency in the light receiving element 20 can be increased.
　そして、図７に示すように、本実施の形態では、投光素子１０からの光が投光レンズ３１ａによって焦点Ｆ１に集光するように設定されている。つまり、投光レンズ３１ａから出射する光の集光点は、焦点Ｆ１に一致している。例えば、投光レンズ３１ａが凸レンズ等の集光レンズである場合は、投光レンズ３１ａの焦点を反射体４０（楕円ミラー）の焦点Ｆ１に一致させればよい。また、投光レンズ３１ａがコリメートレンズである場合は、投光レンズ３１ａから出射する光を投光絞り部７１によって焦点Ｆ１に集光させればよい。 And in this Embodiment, as shown in FIG. 7, it sets so that the light from the light projection element 10 may be condensed on the focus F1 by the light projection lens 31a. That is, the condensing point of the light emitted from the light projecting lens 31a coincides with the focal point F1. For example, when the light projection lens 31a is a condensing lens such as a convex lens, the focal point of the light projection lens 31a may be made coincident with the focal point F1 of the reflector 40 (elliptical mirror). When the light projecting lens 31a is a collimating lens, the light emitted from the light projecting lens 31a may be condensed at the focal point F1 by the light projecting diaphragm 71.
　このように、投光レンズ３１ａから出射する光の集光点を、反射体４０の楕円の焦点Ｆ１に一致させることによって、光の密度が大きくとることができ、検知領域ＤＡにおける粒子の散乱光が大きくなる。したがって、粒子の検出精度を向上させることができる。 Thus, by making the condensing point of the light emitted from the light projecting lens 31a coincide with the elliptical focus F1 of the reflector 40, the light density can be increased, and the scattered light of the particles in the detection area DA. Becomes larger. Therefore, the particle detection accuracy can be improved.
　なお、本実施の形態では、検知領域ＤＡと受光素子２０との間に第２保護板８２が配置されているので、第２保護板８２の屈折率を考慮した上で、反射体４０の焦点位置に検知領域ＤＡと受光素子２０とを配置するとよい。 In the present embodiment, since the second protective plate 82 is disposed between the detection area DA and the light receiving element 20, the focus of the reflector 40 is taken into consideration in consideration of the refractive index of the second protective plate 82. The detection area DA and the light receiving element 20 may be disposed at the positions.
　図６（ｄ）に戻り、本実施の形態において、加熱装置５０は、第１遮光体６１と大気導入孔３５との間に配置されており、かつ、大気導入孔３５を覆うように配置されている。また、大気導入孔３５と、加熱装置５０と、第１遮光体６１と、検知領域ＤＡと、第２遮光体６２と、大気排出孔３６とは、同一直線上に存在するように配置されている。 Returning to FIG. 6D, in the present embodiment, the heating device 50 is disposed between the first light shield 61 and the air introduction hole 35 and is disposed so as to cover the air introduction hole 35. ing. In addition, the air introduction hole 35, the heating device 50, the first light shield 61, the detection area DA, the second light shield 62, and the air discharge hole 36 are arranged so as to exist on the same straight line. Yes.
　第１遮光体６１及び第２遮光体６２は、加熱装置５０から放出される光（ヒータ光）及び当該粒子検出センサ２の外部から内部に進入する光（外光）の少なくとも一方を遮光する。加熱装置５０から放出される光ヒータ光には、可視光及び赤外光が含まれる。第１遮光体６１及び第２遮光体６２は、筐体３０と同一材料によって筐体３０と一体成型されているが、筐体３０と別体でもよい。 The first light shielding body 61 and the second light shielding body 62 shield at least one of light emitted from the heating device 50 (heater light) and light entering from the outside of the particle detection sensor 2 (external light). The light heater light emitted from the heating device 50 includes visible light and infrared light. The first light shielding body 61 and the second light shielding body 62 are integrally formed with the housing 30 using the same material as the housing 30, but may be separate from the housing 30.
　ここで、図６（ｄ）を参照しながら図８Ａ及び図８Ｂを用いて第１遮光体６１及び第２遮光体６２を詳細に説明する。図８Ａは、実施の形態２に係る粒子検出センサ２における第１遮光体６１周辺の構成を示す拡大断面図であり、図８Ｂは、同粒子検出センサ２における第２遮光体６２周辺の構成を示す拡大断面図である。 Here, the first light shield 61 and the second light shield 62 will be described in detail with reference to FIG. 6D with reference to FIGS. 8A and 8B. FIG. 8A is an enlarged cross-sectional view showing the configuration around the first light shield 61 in the particle detection sensor 2 according to Embodiment 2, and FIG. 8B shows the configuration around the second light shield 62 in the particle detection sensor 2. It is an expanded sectional view shown.
　図６（ｄ）及び図８Ａに示すように、第１遮光体６１は、ヒータ光を遮蔽するヒータ光遮蔽体であり、加熱装置５０と検知領域ＤＡとの間に配置されている。本実施の形態における第１遮光体６１は、さらに、大気導入孔３５を介して当該粒子検出センサ２の外部から内部に進入する光（外光）も遮蔽する入口外光遮蔽体でもある。 As shown in FIG. 6D and FIG. 8A, the first light shield 61 is a heater light shield that shields the heater light, and is disposed between the heating device 50 and the detection area DA. The first light shield 61 in the present embodiment is also an entrance outside light shield that shields light (external light) that enters the inside of the particle detection sensor 2 from the outside through the atmosphere introduction hole 35.
　本実施の形態において、第１遮光体６１は、第１遮光壁６１ａと第２遮光壁６１ｂとによって構成されている。第１遮光壁６１ａと第２遮光壁６１ｂは、加熱装置５０から検知領域ＤＡに向かう方向に並んで配置されている。このようにヒータ光及び外光を遮光することによって、粒子の検出精度を向上させることができる。 In the present embodiment, the first light shield 61 is constituted by a first light shield wall 61a and a second light shield wall 61b. The first light shielding wall 61a and the second light shielding wall 61b are arranged side by side in the direction from the heating device 50 toward the detection area DA. Thus, the detection accuracy of the particles can be improved by shielding the heater light and the outside light.
　第１遮光壁６１ａは、加熱装置５０に対向するように配置されている。第２遮光壁６１ｂは、第１遮光壁６１ａ及び加熱装置５０の側部を囲むように、かつ、第１遮光壁６１ａの検知領域ＤＡ側の面の一部を覆うように略箱状に形成されている。また、第２遮光壁６１ｂは、検知領域ＤＡに対向する位置に設けられた開口を有する。第１遮光壁６１ａは、第２遮光壁６１ｂの開口を覆うように設けられている。なお、第１遮光壁６１ａ及び第２遮光壁６１ｂは、粒子検出センサ２内に導入した大気を検知領域ＤＡに導くことができるように設けられている。 The first light shielding wall 61a is arranged to face the heating device 50. The second light shielding wall 61b is formed in a substantially box shape so as to surround the first light shielding wall 61a and the side portion of the heating device 50 and to cover a part of the surface of the first light shielding wall 61a on the detection area DA side. Has been. The second light shielding wall 61b has an opening provided at a position facing the detection area DA. The first light shielding wall 61a is provided so as to cover the opening of the second light shielding wall 61b. The first light shielding wall 61a and the second light shielding wall 61b are provided so that the air introduced into the particle detection sensor 2 can be guided to the detection area DA.
　第１遮光体６１をこのように構成することにより、大気導入孔３５から筐体３０に導入された粒子は、加熱装置５０及び第１遮光壁６１ａの各々の両側部と第２遮光壁６１ｂの内側面との２つの間を通って第２遮光壁６１ｂの開口を介して検知領域ＤＡに進むことになる。つまり、第１遮光体６１における粒子流路３３は、大気導入孔３５の入口付近で一旦２つに分岐されて第１遮光壁６１ａの検知領域ＤＡ側の面で再び１つに合流する流路となっている。これにより、ヒータ光や外光が検知領域ＤＡに進入することを抑制しつつ、粒子検出センサ２内に導入した大気を検知領域ＤＡにきちんと導くことができる。 By configuring the first light shield 61 in this way, the particles introduced into the housing 30 from the air introduction hole 35 are caused to flow on both sides of the heating device 50 and the first light shield wall 61a and the second light shield wall 61b. It goes to the detection area DA through the opening of the second light shielding wall 61b through the space between the inner surface and the two. That is, the particle flow path 33 in the first light shielding body 61 is once branched into two near the inlet of the air introduction hole 35 and merged again into one on the surface of the first light shielding wall 61a on the detection area DA side. It has become. Thereby, the atmosphere introduced into the particle detection sensor 2 can be properly guided to the detection area DA while suppressing the heater light and the outside light from entering the detection area DA.
　また、第２遮光体６２は、図６（ｄ）及び図８Ｂに示すように、大気排出孔３６を介して当該粒子検出センサ２の外部から内部に進入する光（外光）を遮光する出口外光遮蔽体である。このように外光を遮光することによって、粒子の検出精度を向上させることができる。 Further, as shown in FIG. 6D and FIG. 8B, the second light blocking body 62 is an outlet that blocks light (external light) that enters the particle detection sensor 2 from the outside through the air discharge hole 36. It is an external light shield. Thus, by blocking external light, the particle detection accuracy can be improved.
　第２遮光体６２は、検知領域ＤＡから大気排出孔３６に向かう方向に並んで配置された複数の遮蔽壁を有する。この複数の遮蔽体は、粒子検出センサ２の内部の大気を大気排出孔３６から排出できるように構成されている。 The second light shielding body 62 has a plurality of shielding walls arranged side by side in the direction from the detection area DA toward the air discharge hole 36. The plurality of shields are configured so that the air inside the particle detection sensor 2 can be discharged from the air discharge hole 36.
　本実施の形態における第２遮光体６２は、第１遮光壁６２ａと第２遮光壁６２ｂと第３遮光壁６２ｃとによって構成されている。第１遮光壁６２ａは、大気排出孔３６に対向するように、かつ、大気排出孔３６を覆うように配置されている。第２遮光壁６２ｂは、第１遮光壁６２ａの側部を囲むように形成されている。本実施の形態において、第３遮光壁６２ｃは、反射体４０の側壁である。具体的には、第３遮光壁６２ｃは、反射体４０が配置される受光領域３２の側壁である。第１遮光壁６２ａ、第２遮光壁６２ｂ及び第３遮光壁６２ｃは、粒子検出センサ２の内部の大気を大気排出孔３６から排出できるように構成されている。 The second light shield 62 in the present embodiment is configured by a first light shield wall 62a, a second light shield wall 62b, and a third light shield wall 62c. The first light shielding wall 62 a is disposed so as to face the air discharge hole 36 and cover the air discharge hole 36. The second light shielding wall 62b is formed so as to surround the side portion of the first light shielding wall 62a. In the present embodiment, the third light shielding wall 62 c is a side wall of the reflector 40. Specifically, the third light shielding wall 62c is a side wall of the light receiving region 32 where the reflector 40 is disposed. The first light shielding wall 62a, the second light shielding wall 62b, and the third light shielding wall 62c are configured so that the air inside the particle detection sensor 2 can be discharged from the air discharge hole 36.
　第２遮光体６２をこのように構成することにより、迷光や外光が検知領域ＤＡに進入することを抑制しつつ、粒子検出センサ２から大気をきちんと排出することができる。 By configuring the second light shielding body 62 in this manner, the atmosphere can be exhausted from the particle detection sensor 2 while suppressing stray light and external light from entering the detection area DA.
　また、図６（ｄ）に示すように、第１遮光体６１及び第２遮光体６２はいずれも、検知領域ＤＡの粒子による散乱光が第１遮光体６１及び第２遮光体６２に到達した場合に、当該散乱光が検知領域ＤＡに反射することを抑制する形状となっている。例えば、第１遮光体６１及び第２遮光体６２は、検知領域ＤＡにおける粒子の散乱光を検知領域ＤＡ以外の方向に反射させる反射面を有する。これにより、ヒータ光及び外光を遮光しつつ、検知領域ＤＡに不要な光が進入することを抑制できるので、粒子の検出精度を一層向上させることができる。 Further, as shown in FIG. 6D, in both the first light shield 61 and the second light shield 62, the scattered light from the particles in the detection area DA has reached the first light shield 61 and the second light shield 62. In such a case, the scattered light is prevented from being reflected on the detection area DA. For example, the first light shield 61 and the second light shield 62 have reflection surfaces that reflect the scattered light of the particles in the detection area DA in directions other than the detection area DA. Thereby, since it is possible to suppress unnecessary light from entering the detection area DA while shielding the heater light and the external light, it is possible to further improve the particle detection accuracy.
　本実施の形態において、第１遮光体６１では、第１遮光壁６１ａの検知領域ＤＡ側の面が、検知領域ＤＡからの散乱光が入射したときに当該散乱光を大気導入孔３５に導くような形状となっている。具体的には、第１遮光壁６１ａの検知領域ＤＡ側の面は、当該散乱光を大気導入孔３５に導くように反射する反射面であり、例えば、図８Ａに示すように、検知領域ＤＡに向かって凸状をなす湾曲面である。つまり、第１遮光壁６１ａの検知領域ＤＡ側の面は、第２遮光壁６１ｂに対向する部分（中央）から全方位に向かって鉛直下方に漸次落ち込む形状となっている。これにより、検知領域ＤＡに迷光が進入することを抑制できるので、粒子の検出精度を一層向上させることができる。 In the present embodiment, in the first light shield 61, the surface of the first light shielding wall 61a on the detection area DA side guides the scattered light to the air introduction hole 35 when the scattered light from the detection area DA is incident. It has become a shape. Specifically, the surface on the detection area DA side of the first light shielding wall 61a is a reflection surface that reflects the scattered light so as to guide it to the air introduction hole 35. For example, as shown in FIG. 8A, the detection area DA It is a curved surface which forms a convex shape toward. That is, the surface of the first light shielding wall 61a on the detection area DA side has a shape that gradually falls vertically downward from the portion (center) facing the second light shielding wall 61b in all directions. Thereby, since stray light can be prevented from entering the detection area DA, the particle detection accuracy can be further improved.
　また、第１遮光壁６１ａの加熱装置５０側の面（本実施の形態では、第１遮光壁６１ａの大気導入孔３５側の面でもある）は、加熱装置５０からのヒータ光及び大気導入孔３５を介して筐体３０の内部に進入する外光を大気導入孔３５に導くような形状となっている。具体的には、第１遮光壁６１ａの加熱装置５０側の面は、ヒータ光及び外光を大気導入孔３５に導くように反射する反射面であり、本実施の形態では、検知領域ＤＡに向かって凸状をなす湾曲面である。つまり、第１遮光壁６１ａの加熱装置５０側の面は、中央から全方位に向かって鉛直下方に漸次落ち込む形状となっている。これにより、検知領域ＤＡに不要な光が進入することを抑制できるので、粒子の検出精度をさらに向上させることができる。 Further, the surface of the first light shielding wall 61a on the heating device 50 side (in this embodiment, also the surface of the first light shielding wall 61a on the air introduction hole 35 side) is the heater light from the heating device 50 and the air introduction hole. The external light entering the inside of the housing 30 via the 35 is guided to the air introduction hole 35. Specifically, the surface on the heating device 50 side of the first light shielding wall 61a is a reflective surface that reflects the heater light and the outside light so as to guide the air to the atmosphere introduction hole 35. It is a curved surface that forms a convex shape. That is, the surface of the first light shielding wall 61a on the heating device 50 side has a shape that gradually falls downward vertically from the center in all directions. Thereby, since unnecessary light can enter the detection area DA, the particle detection accuracy can be further improved.
　一方、第２遮光体６２では、第１遮光壁６２ａの検知領域ＤＡ側の面が、検知領域ＤＡからの散乱光が入射したときに当該散乱光を大気排出孔３６に導くような形状となっている。具体的には、第１遮光壁６２ａの検知領域ＤＡ側の面は、当該散乱光を大気排出孔３６に導くように反射する反射面であり、例えば、図８Ｂに示すように、検知領域ＤＡに向かって凸状をなす湾曲面である。つまり、第１遮光壁６２ａの検知領域ＤＡ側の面は、中央から全方位に向かって鉛直上方に漸次せり上がる形状となっている。これにより、検知領域ＤＡに迷光が進入することを抑制できるので、粒子の検出精度を一層向上させることができる。 On the other hand, in the second light shielding body 62, the surface on the detection area DA side of the first light shielding wall 62a has a shape that guides the scattered light to the air discharge hole 36 when the scattered light from the detection area DA is incident. ing. Specifically, the surface on the detection area DA side of the first light shielding wall 62a is a reflection surface that reflects the scattered light so as to guide it to the air discharge hole 36. For example, as shown in FIG. 8B, the detection area DA It is a curved surface which forms a convex shape toward. That is, the surface of the first light shielding wall 62a on the detection area DA side has a shape that gradually rises vertically upward from the center in all directions. Thereby, since stray light can be prevented from entering the detection area DA, the particle detection accuracy can be further improved.
　また、第１遮光壁６２ａの大気排出孔３６側の面は、大気排出孔３６を介して筐体３０の内部に進入する外光を大気排出孔３６に導くような形状となっている。具体的には、第１遮光壁６２ａの大気排出孔３６側の面は、外光を大気排出孔３６に導くように反射する反射面であり、本実施の形態では、検知領域ＤＡに向かって凸状をなす湾曲面である。つまり、第１遮光壁６２ａの大気排出孔３６側の面は、中央から全方位に向かって鉛直上方に漸次せり上がる形状となっている。これにより、検知領域ＤＡに不要な光が進入することを抑制できるので、粒子の検出精度をさらに向上させることができる。 In addition, the surface of the first light shielding wall 62a on the atmosphere discharge hole 36 side has a shape that guides external light entering the inside of the housing 30 through the atmosphere discharge hole 36 to the atmosphere discharge hole 36. Specifically, the surface on the atmosphere discharge hole 36 side of the first light shielding wall 62a is a reflection surface that reflects external light so as to guide it to the atmosphere discharge hole 36, and in the present embodiment, toward the detection area DA. It is a curved surface having a convex shape. That is, the surface of the first light shielding wall 62a on the atmosphere exhaust hole 36 side has a shape that gradually rises vertically upward from the center in all directions. Thereby, since unnecessary light can enter the detection area DA, the particle detection accuracy can be further improved.
　図６（ｄ）に戻り、第１保護板８１は、粒子が投光領域３１に入り込まないようにするための保護部材である。また、第２保護板８２は、粒子が受光領域３２に入り込まないようにするための保護部材である。第１保護板８１及び第２保護板８２の各々は、大気中に浮遊する粒子（ホコリ・花粉・煙・ＰＭ２．５等）が粒子検出センサ２の動作中及び非動作中に筐体３０内に入ってきた場合に、当該粒子が投光領域３１及び受光領域３２の各々に入り込まないようにする。 6D, the first protective plate 81 is a protective member for preventing particles from entering the light projecting region 31. The second protective plate 82 is a protective member for preventing particles from entering the light receiving region 32. Each of the first protective plate 81 and the second protective plate 82 is formed in the housing 30 while particles floating in the atmosphere (dust, pollen, smoke, PM2.5, etc.) are in operation and non-operation of the particle detection sensor 2. When entering, the particles are prevented from entering each of the light projecting region 31 and the light receiving region 32.
　図６（ｄ）に示すように、第１保護板８１は、投光領域３１の粒子流路３３との接続部分となる開口部（投光領域３１の開口部）を覆うように配置されている。同様に、第２保護板８２は、受光領域３２の粒子流路３３との接続部分となる開口部（受光領域３２の開口部）を覆うように配置されている。より具体的に、第２保護板８２は、反射体４０の開口端面を覆っている。投光領域３１及び受光領域３２の開口部を第１保護板８１及び第２保護板８２で覆うことによって、投光領域３１及び受光領域３２が閉じた空間領域となり、投光領域３１及び受光領域３２の内部にホコリ・花粉・煙等の粒子が入り込むことを防止できる。 As shown in FIG. 6 (d), the first protective plate 81 is disposed so as to cover an opening (an opening of the light projecting region 31) that becomes a connection portion with the particle flow path 33 in the light projecting region 31. Yes. Similarly, the second protective plate 82 is disposed so as to cover an opening (an opening of the light receiving region 32) serving as a connection portion between the light receiving region 32 and the particle flow path 33. More specifically, the second protective plate 82 covers the opening end surface of the reflector 40. By covering the openings of the light projecting region 31 and the light receiving region 32 with the first protective plate 81 and the second protective plate 82, the light projecting region 31 and the light receiving region 32 become a closed space region. It is possible to prevent particles such as dust, pollen and smoke from entering the interior of 32.
　第１保護板８１及び第２保護板８２は、厚みが一様の平板状の透明板であり、例えば、ガラス、又は、ポリカーボネートやアクリル等の透明樹脂によって構成されている。一例として、第１保護板８１及び第２保護板８２は、屈折率が１．５以下で、厚みが２００μｍ以下の透明板である。第１保護板８１及び第２保護板８２の全透過率は、フレネル反射を無視すれば、例えば９９％以上である。 The first protective plate 81 and the second protective plate 82 are flat transparent plates having a uniform thickness, and are made of, for example, glass or a transparent resin such as polycarbonate or acrylic. As an example, the first protective plate 81 and the second protective plate 82 are transparent plates having a refractive index of 1.5 or less and a thickness of 200 μm or less. The total transmittance of the first protective plate 81 and the second protective plate 82 is, for example, 99% or more if the Fresnel reflection is ignored.
　なお、第２保護板８２の表面で粒子の散乱光が散乱しないように、第２保護板８２の表面は平滑面であるとよい。これにより、第２保護板８２による散乱光の光路の位置ずれを小さくできる。 The surface of the second protective plate 82 is preferably a smooth surface so that the scattered light of the particles is not scattered on the surface of the second protective plate 82. Thereby, the position shift of the optical path of the scattered light by the 2nd protection board 82 can be made small.
　このように構成される本実施の形態における粒子検出センサ２は、図２Ａ、図２Ｂ及び図２Ｃで説明したように、実施の形態１における粒子検出センサ１と同様の動作によって粒子を検出することができる。 As described in FIGS. 2A, 2B, and 2C, the particle detection sensor 2 in the present embodiment configured as described above detects particles by the same operation as the particle detection sensor 1 in the first embodiment. Can do.
　以上、本実施の形態における粒子検出センサ２は、実施の形態１における粒子検出センサ１と同様に、反射体４０を備えている。 As described above, the particle detection sensor 2 in the present embodiment includes the reflector 40 as in the particle detection sensor 1 in the first embodiment.
　これにより、受光領域３２にレンズを設ける場合と比べて受光感度を高くすることができる。したがって、加熱装置５０を用いた加熱方式の粒子検出センサであっても、気体中に含まれる粒子が、ホコリであるか、花粉であるか、煙であるかを判別できるだけではなく、ＰＭ２．５（微小粒子状物質）のように粒径の小さな微粒子までも判別することができる。このように、本実施の形態に係る粒子検出センサ２でも、低コストかつ小型でありながら、高精度の粒子検出センサを実現することができる。 Thereby, the light receiving sensitivity can be increased as compared with the case where a lens is provided in the light receiving region 32. Therefore, even in a heating type particle detection sensor using the heating device 50, not only can the particle contained in the gas be dust, pollen, or smoke, but also PM2.5. Even fine particles having a small particle diameter such as (microparticulate matter) can be distinguished. Thus, even with the particle detection sensor 2 according to the present embodiment, a highly accurate particle detection sensor can be realized while being low-cost and small.
　また、本実施の形態における粒子検出センサ２では、加熱装置５０から放出されるヒータ光及び粒子検出センサ１の外部から内部に進入する外光の少なくとも一方を遮光する遮光体を備えており、当該遮光体は、検知領域ＤＡにおける粒子の散乱光が当該遮光体に到達した場合に、当該散乱光が検知領域ＤＡに反射することを抑制する形状となっている。 Further, the particle detection sensor 2 in the present embodiment includes a light shielding body that shields at least one of the heater light emitted from the heating device 50 and the external light entering the inside from the outside of the particle detection sensor 1. The light shielding body has a shape that suppresses reflection of the scattered light to the detection area DA when the scattered light of the particles in the detection area DA reaches the light shielding body.
　具体的には、粒子検出センサ２は、加熱装置５０（ヒータ）から放出されるヒータ光及び大気導入孔３５から粒子検出センサ２の内部に進入する外光を遮光する第１遮光体６１と、大気排出孔３６から粒子検出センサ２の内部に進入する外光を遮光する第２遮光体６２とを備えている。 Specifically, the particle detection sensor 2 includes a first light shield 61 that shields heater light emitted from the heating device 50 (heater) and external light entering the particle detection sensor 2 from the air introduction hole 35; A second light shielding body 62 that shields external light entering the inside of the particle detection sensor 2 from the air discharge hole 36 is provided.
　これにより、ヒータ光及び外光を遮光することができるので、粒子の検出精度を向上させることができる。 Thereby, since the heater light and the outside light can be shielded, the particle detection accuracy can be improved.
　しかも、第１遮光体６１及び第２遮光体６２は、検知領域ＤＡにおける粒子の散乱光が第１遮光体６１及び第２遮光体６２で反射して検知領域ＤＡに向かうことを抑制する形状となっている。 Moreover, the first light shielding body 61 and the second light shielding body 62 have a shape that suppresses the scattered light of the particles in the detection area DA from being reflected by the first light shielding body 61 and the second light shielding body 62 toward the detection area DA. It has become.
　これにより、ヒータ光及び外光を遮光しつつ、検知領域ＤＡに不要な散乱光（迷光）が進入することを抑制できるので、粒子の検出精度を一層向上させることができる。したがって、低コストでありながら、検出精度に優れたセンサを実現することができる。 Thereby, since it is possible to suppress unnecessary scattered light (stray light) from entering the detection area DA while shielding the heater light and the outside light, the particle detection accuracy can be further improved. Therefore, it is possible to realize a sensor with excellent detection accuracy at a low cost.
　また、本実施の形態において、第１遮光体６１（第１遮光壁６１ａ）の検知領域ＤＡ側の面が、検知領域ＤＡからの散乱光が入射したときに当該散乱光を大気導入孔３５に導くような形状となっている。具体的には、第１遮光体６１（第１遮光壁６１ａ）の検知領域ＤＡ側の面は、当該散乱光を大気導入孔３５に導くように反射する反射面である。 Further, in the present embodiment, when the scattered light from the detection area DA is incident on the surface on the detection area DA side of the first light shielding body 61 (first light shielding wall 61a), the scattered light enters the air introduction hole 35. It has a shape that leads. Specifically, the surface on the detection area DA side of the first light shield 61 (first light shield wall 61 a) is a reflective surface that reflects the scattered light so as to guide it to the air introduction hole 35.
　これにより、検知領域ＤＡに迷光が進入することを一層抑制できるので、粒子の検出精度を一層向上させることができる。 As a result, stray light can be further prevented from entering the detection area DA, so that the particle detection accuracy can be further improved.
　同様に、第２遮光体６２（第１遮光壁６２ａ）の検知領域ＤＡ側の面が、検知領域ＤＡからの散乱光が入射したときに当該散乱光を大気導入孔３５に導くような形状となっている。具体的には、第２遮光体６２（第１遮光壁６２ａ）の検知領域ＤＡ側の面は、当該散乱光を大気排出孔３６に導くように反射する反射面である。 Similarly, the surface of the second light shielding body 62 (first light shielding wall 62a) on the detection area DA side has a shape that guides the scattered light to the air introduction hole 35 when the scattered light from the detection area DA is incident. It has become. Specifically, the surface on the detection area DA side of the second light shielding body 62 (first light shielding wall 62 a) is a reflecting surface that reflects the scattered light so as to guide it to the air discharge hole 36.
　これにより、検知領域ＤＡに迷光が進入することを一層抑制できるので、粒子の検出精度を一層向上させることができる。 As a result, stray light can be further prevented from entering the detection area DA, so that the particle detection accuracy can be further improved.
　また、本実施の形態において、第１遮光体６１（第１遮光壁６１ａ）の加熱装置５０側の面（大気導入孔３５側の面）は、ヒータ光及び外光を大気導入孔３５に導くような形状となっている。具体的には、第１遮光体６１（第１遮光壁６１ａ）の加熱装置５０側の面は、ヒータ光及び外光を大気導入孔３５に導くように反射する反射面である。 In the present embodiment, the surface on the heating device 50 side (the surface on the atmosphere introduction hole 35 side) of the first light shielding body 61 (first light shielding wall 61a) guides the heater light and the external light to the atmosphere introduction hole 35. It has a shape like this. Specifically, the surface on the heating device 50 side of the first light shielding body 61 (first light shielding wall 61 a) is a reflecting surface that reflects the heater light and the external light so as to guide the air to the atmosphere introduction hole 35.
　これにより、検知領域ＤＡに不要な光が進入することを一層抑制できるので、粒子の検出精度を一層向上させることができる。 As a result, it is possible to further prevent unnecessary light from entering the detection area DA, thereby further improving the particle detection accuracy.
　同様に、第２遮光体６２（第１遮光壁６２ａ）の大気排出孔３６側の面は、外光を大気排出孔３６に導くような形状となっている。具体的には、第２遮光体６２（第１遮光壁６２ａ）の大気排出孔３６側の面は、外光を大気排出孔３６に導くように反射する反射面である。 Similarly, the surface of the second light shielding body 62 (first light shielding wall 62 a) on the atmosphere discharge hole 36 side is shaped to guide external light to the atmosphere discharge hole 36. Specifically, the surface of the second light shielding body 62 (first light shielding wall 62 a) on the atmosphere discharge hole 36 side is a reflection surface that reflects external light so as to guide it to the atmosphere discharge hole 36.
　これにより、検知領域ＤＡに不要な光が進入することを一層抑制できるので、粒子の検出精度を一層向上させることができる。 As a result, it is possible to further prevent unnecessary light from entering the detection area DA, thereby further improving the particle detection accuracy.
　また、本実施の形態において、第１遮光体６１は、検知領域ＤＡに対向する開口を有する第２遮光壁６１ｂと、第２遮光壁６１ｂの開口を覆う第１遮光壁６１ａとからなる。また、第１遮光壁６１ａと第２遮光壁６１ｂとは、加熱装置５０から検知領域ＤＡに向かう方向に並ぶように配置されており、かつ、粒子検出センサ１内に導入した大気を検知領域ＤＡに導くことができるように設けられている。 In the present embodiment, the first light shield 61 includes a second light shield wall 61b having an opening facing the detection area DA, and a first light shield wall 61a covering the opening of the second light shield wall 61b. The first light shielding wall 61a and the second light shielding wall 61b are arranged so as to be aligned in the direction from the heating device 50 toward the detection area DA, and the atmosphere introduced into the particle detection sensor 1 is detected in the detection area DA. It is provided so that it can be led to.
　これにより、ヒータ光や外光が検知領域ＤＡに進入することを抑制しつつ、粒子検出センサ１内に導入した大気を検知領域ＤＡにきちんと導くことができる。 Thereby, the atmosphere introduced into the particle detection sensor 1 can be properly guided to the detection area DA while suppressing the heater light and external light from entering the detection area DA.
　また、本実施の形態において、第２遮光体６２は、検知領域ＤＡから大気排出孔３６に向かう方向に並んで配置された複数の遮蔽壁（第１遮光壁６２ａ、第２遮光壁６２ｂ、第３遮光壁６２ｃ）を有しており、かつ、これらの複数の遮蔽体は、粒子検出センサ１の内部の大気を大気排出孔３６から排出できるように構成されている。 Further, in the present embodiment, the second light shielding body 62 has a plurality of shielding walls (first light shielding wall 62a, second light shielding wall 62b, 3 light shielding walls 62c), and the plurality of shields are configured so that the air inside the particle detection sensor 1 can be discharged from the air discharge hole 36.
　これにより、外光や迷光が検知領域ＤＡに進入することを抑制しつつ、粒子検出センサ１から大気をきちんと排出することができる。 Thus, the atmosphere can be properly discharged from the particle detection sensor 1 while suppressing external light and stray light from entering the detection area DA.
　また、図６（ｄ）に示すように、本実施の形態において、反射体４０（受光領域３２）は、粒子流路３３内に伸びるように設けられており、反射体４０（受光領域３２）の一部が大気排出孔３６及び第２遮光体６２の第１遮光壁６２ａと検知領域ＤＡとの間に存在している。つまり、反射体４０（受光領域３２）の一部が検知領域ＤＡの鉛直上方に位置している。また、反射体４０（受光領域３２）の開口部は第２保護板８２で覆われている。 Further, as shown in FIG. 6D, in the present embodiment, the reflector 40 (light receiving region 32) is provided so as to extend into the particle flow path 33, and the reflector 40 (light receiving region 32). Is present between the air discharge hole 36 and the first light shielding wall 62a of the second light shielding body 62 and the detection area DA. That is, a part of the reflector 40 (light receiving area 32) is positioned vertically above the detection area DA. The opening of the reflector 40 (light receiving region 32) is covered with a second protective plate 82.
　これにより、粒子検出センサ２（筐体３０）内に導入された粒子を含む大気は、第２保護板８２にぶつかって第２保護板８２付近で一旦滞留することになる。本実施の形態では、検知領域ＤＡが第２保護板８２付近に位置するように設定されているので、粒子を含む大気は、検知領域ＤＡにおいて一旦滞留することになる。したがって、異なる粒子を含む大気を導入する場合であっても、検知領域ＤＡ付近で一定の速度にすることができるので、粒子の検出精度を一層向上させることができる。 Thus, the atmosphere containing the particles introduced into the particle detection sensor 2 (housing 30) collides with the second protection plate 82 and temporarily stays in the vicinity of the second protection plate 82. In the present embodiment, since the detection area DA is set so as to be positioned in the vicinity of the second protective plate 82, the atmosphere containing particles once stays in the detection area DA. Therefore, even when air containing different particles is introduced, the speed can be made constant in the vicinity of the detection area DA, so that the particle detection accuracy can be further improved.
　ここで、図９を用いて、本実施の形態に係る粒子検出センサにおける投光素子１０から出射して検知領域ＤＡに向かう光の光路について説明する。図５は、その光路を説明するための図である。 Here, with reference to FIG. 9, an optical path of light emitted from the light projecting element 10 in the particle detection sensor according to the present embodiment and traveling toward the detection area DA will be described. FIG. 5 is a diagram for explaining the optical path.
　図９に示すように、本実施の形態では、投光絞り部７１における複数の光学絞りの各々の開口の先端を結ぶ仮想線７１Ｌと、投光素子１０から出射して検知領域ＤＡに向かう光の輪郭線（ライン）１０Ｌとが略平行となるように、光のラインが設計されている。具体的には、仮想線７１Ｌと、投光素子１０から出射して投光レンズ３１ａによって屈折する光の輪郭線１０Ｌとが略平行である。つまり、投光素子１０から出射して投光レンズ３１ａによって屈折する光は、投光絞り部７１における複数の光学絞りの各々の開口の先端を結んでできる仮想空間領域の内側を通って検知領域ＤＡに進行する。 As shown in FIG. 9, in the present embodiment, a virtual line 71L that connects the tips of the openings of the plurality of optical apertures in the light projection aperture section 71, and light emitted from the light projecting element 10 and traveling toward the detection area DA. The light line is designed so that the contour line (line) 10L is substantially parallel. Specifically, the virtual line 71L and the contour line 10L of the light emitted from the light projecting element 10 and refracted by the light projecting lens 31a are substantially parallel. That is, the light emitted from the light projecting element 10 and refracted by the light projecting lens 31a passes through the inside of the virtual space region formed by connecting the tips of the openings of the plurality of optical diaphragms in the light projecting diaphragm section 71, and the detection area. Proceed to DA.
　これにより、設計外の光を確実に封じ込めることができるので、投光領域３１において迷光が発生することを抑制できる。したがって、粒子の検出精度を一層向上させることができる。 This makes it possible to reliably contain light outside the design, so that stray light can be prevented from being generated in the light projecting region 31. Therefore, the particle detection accuracy can be further improved.
　また、投光反対絞り部７２における複数の光学絞りの各々の開口の先端を結ぶ仮想線７２Ｌと、投光素子１０から出射して検知領域ＤＡを通過する光の輪郭線（ライン）１０Ｌとが略平行となるように、光のラインが設計されている。具体的には、仮想線７２Ｌと、投光素子１０から出射して検知領域ＤＡを通って投光トラップ部３４ａ内に進入する光の輪郭線１０Ｌとが略平行である。つまり、投光素子１０から出射して投光レンズ３１ａによって一旦検知領域ＤＡで集光してから発散するように投光トラップ部３４ａ内に進入する光は、投光反対絞り部７２における複数の光学絞りの各々の開口の先端を結んでできる仮想空間領域の内側を通って投光トラップ部３４ａの奥に進入する。 Further, a virtual line 72L that connects the tips of the openings of the plurality of optical stops in the light projection opposite stop 72, and a contour line (line) 10L of light that is emitted from the light projecting element 10 and passes through the detection area DA. The light lines are designed to be substantially parallel. Specifically, the imaginary line 72L and the outline 10L of the light emitted from the light projecting element 10 and entering the light projecting trap part 34a through the detection area DA are substantially parallel. That is, the light that enters the light projecting trap part 34a so as to be emitted from the light projecting element 10 and once converged in the detection area DA by the light projecting lens 31a and then diverge is a plurality of light in the light projecting opposite aperture part 72. The light passes through the inside of a virtual space region formed by connecting the tips of the openings of the optical diaphragms and enters the depth of the light projection trap part 34a.
　これにより、設計外の光を確実に封じ込めることができるので、投光トラップ部３４ａにおいて迷光が発生することを抑制できる。したがって、粒子の検出精度を一層向上させることができる。 This makes it possible to reliably contain light outside the design, so that stray light can be prevented from occurring in the light projecting trap part 34a. Therefore, the particle detection accuracy can be further improved.
　なお、受光反対絞り部７３における複数の光学絞りについても、検知領域ＤＡにおける粒子の散乱光に対して同様の構成にしてもよい。 Note that the plurality of optical stops in the light receiving opposite stop portion 73 may have the same configuration with respect to the scattered light of the particles in the detection area DA.
　また、同図に示すように、本実施の形態では、投光素子１０から出射して検知領域ＤＡに向かう光の輪郭線（ライン）１０Ｌと反射体４０の端面を結ぶ仮想線４０Ｌとが略平行である。 Further, as shown in the figure, in the present embodiment, a light outline (line) 10L emitted from the light projecting element 10 toward the detection area DA and a virtual line 40L connecting the end face of the reflector 40 are approximately. Parallel.
　これにより、感度を向上させることができるので、粒子の検出精度を一層向上させることができる。 Thereby, the sensitivity can be improved, so that the particle detection accuracy can be further improved.
　（実施の形態３）
　次に、実施の形態３に係る粒子検出センサ３の構成について、図１０を用いて説明する。図１０は、実施の形態３に係る粒子検出センサ３の構成を示す図であり、（ａ）は上面図、（ｂ）は正面図、（ｃ）は下面図、（ｄ）は（ａ）のＡ－Ａ線における断面図である。なお、本実施の形態でも、図１０（ｄ）における大気排出孔３６から大気導入孔３５に向かう方向を鉛直下方（重力方向）としている。 (Embodiment 3)
Next, the configuration of the particle detection sensor 3 according to Embodiment 3 will be described with reference to FIG. 10A and 10B are diagrams showing the configuration of the particle detection sensor 3 according to Embodiment 3, wherein FIG. 10A is a top view, FIG. 10B is a front view, FIG. 10C is a bottom view, and FIG. It is sectional drawing in the AA of FIG. Also in this embodiment, the direction from the air discharge hole 36 to the air introduction hole 35 in FIG.
　図１０に示すように、本実施の形態における粒子検出センサ３は、実施の形態１における粒子検出センサ１に対して、さらに、透光性を有する第１保護板９１を有する。第１保護板９１は、筐体３０内に配置されている。具体的に、第１保護板９１は、粒子流路３３と受光領域３２との接続部分に配置されている。 As shown in FIG. 10, the particle detection sensor 3 in the present embodiment further includes a first protective plate 91 having translucency with respect to the particle detection sensor 1 in the first embodiment. The first protection plate 91 is disposed in the housing 30. Specifically, the first protective plate 91 is disposed at a connection portion between the particle flow path 33 and the light receiving region 32.
　第１保護板９１は、粒子が受光領域３２に入り込まないようにするための保護部材である。例えば、第１保護板９１は、大気中に浮遊する粒子（ホコリ・花粉・煙・ＰＭ２．５等）が粒子検出センサ３の動作中及び非動作中に筐体３０内に入ってきた場合に、当該粒子が受光領域３２に入り込まないようにする。 The first protective plate 91 is a protective member for preventing particles from entering the light receiving region 32. For example, the first protective plate 91 is used when particles floating in the atmosphere (dust, pollen, smoke, PM2.5, etc.) enter the housing 30 during operation and non-operation of the particle detection sensor 3. The particles are prevented from entering the light receiving region 32.
　図１０（ｄ）に示すように、本実施の形態において、第１保護板９１は、受光領域３２の粒子流路３３との接続部分となる開口部（受光領域３２の開口部）を覆うように配置されている。つまり、第１保護板９１は受光領域３２に蓋をするように配置されている。受光領域３２の開口部が第１保護板９１で覆われることによって受光領域３２は閉じた空間領域となり、受光領域３２外から受光領域３２内にホコリ・花粉・煙等の粒子が入り込むことを防止できる。 As shown in FIG. 10 (d), in the present embodiment, the first protective plate 91 covers an opening (an opening of the light receiving region 32) that is a connection portion with the particle flow path 33 of the light receiving region 32. Is arranged. That is, the first protective plate 91 is disposed so as to cover the light receiving region 32. By covering the opening of the light receiving area 32 with the first protective plate 91, the light receiving area 32 becomes a closed space area and prevents particles such as dust, pollen, and smoke from entering the light receiving area 32 from outside the light receiving area 32. it can.
　また、本実施の形態において、第１保護板９１の主面と、回転楕円体の回転面からなる反射体４０を構成する楕円の長軸（反射体４０の光軸）及び受光素子２０の光軸とは、直角をなしている。言い換えると、第１保護板９１の主面との法線は、反射体４０を構成する楕円の長軸及び受光素子２０の光軸と平行となっている。 Further, in the present embodiment, the major axis of the ellipse (the optical axis of the reflector 40) and the light of the light receiving element 20 constituting the reflector 40 composed of the main surface of the first protective plate 91 and the rotation surface of the spheroid. The axis forms a right angle. In other words, the normal to the main surface of the first protective plate 91 is parallel to the major axis of the ellipse that constitutes the reflector 40 and the optical axis of the light receiving element 20.
　このように構成される第１保護板９１は、例えば、ガラス、又は、ポリカーボネートやアクリル等の透明樹脂によって構成された透明板である。第１保護板９１の全透過率は、フレネル反射を無視すれば、例えば９９％以上である。また、第１保護板９１としては、厚みが一様の平板を用いている。つまり、第１保護板９１として、全領域において板厚が一定の平板を用いている。なお、第１保護板９１は厚みが一様の平板でなくてもよく、第１保護板９１を受光領域３２に取り付ける等するために、第１保護板９１は、周縁部分が肉薄となっていたり周縁部分の一部が切り欠かれていたりしてもよい。 The first protective plate 91 configured as described above is, for example, a transparent plate made of glass or a transparent resin such as polycarbonate or acrylic. The total transmittance of the first protective plate 91 is, for example, 99% or more if the Fresnel reflection is ignored. Further, as the first protective plate 91, a flat plate having a uniform thickness is used. That is, as the first protective plate 91, a flat plate having a constant thickness in the entire region is used. The first protective plate 91 may not be a flat plate with a uniform thickness. In order to attach the first protective plate 91 to the light receiving region 32, the first protective plate 91 has a thin peripheral portion. Or part of the peripheral edge may be cut out.
　第１保護板９１の平面視形状は、受光領域３２の開口部を覆う形状であればよく、例えば、受光領域３２の開口部の形状が円形である場合は、第１保護板９１としては円板状の透明板を用いればよい。 The shape of the first protective plate 91 in plan view may be a shape that covers the opening of the light receiving region 32. For example, when the shape of the opening of the light receiving region 32 is circular, the first protective plate 91 may be a circle. A plate-like transparent plate may be used.
　また、第１保護板９１は、粒子の散乱光を散乱させないように構成されている。つまり、第１保護板９１で光が散乱しないように、第１保護板９１の表面は、検知領域ＤＡ側の主面も受光素子２０側の主面も平滑面である。 The first protective plate 91 is configured not to scatter the scattered light of the particles. That is, the surface of the first protective plate 91 is a smooth surface on both the main surface on the detection area DA side and the main surface on the light receiving element 20 side so that light is not scattered by the first protective plate 91.
　第１保護板９１としては、屈折率が１．５以下で、厚みが２００μｍ以下の平板を用いるとよい。これにより、第１保護板９１による散乱光の光路の位置ずれを小さくすることができる。 As the first protective plate 91, a flat plate having a refractive index of 1.5 or less and a thickness of 200 μm or less may be used. Thereby, the position shift of the optical path of the scattered light by the 1st protection board 91 can be made small.
　なお、後述するように、第１保護板９１の表面に付着した付着物を綿棒等の清掃具で擦って除去することもあるので、第１保護板９１の表面は、耐摩耗性を有するとよい。したがって、第１保護板９１の表面には、耐摩耗性を向上させるための表面処理又は表面コート処理等が施されているとよい。 As will be described later, since the adhering matter adhering to the surface of the first protective plate 91 may be removed by rubbing with a cleaning tool such as a cotton swab, the surface of the first protective plate 91 has wear resistance. Good. Therefore, the surface of the first protective plate 91 may be subjected to surface treatment or surface coating treatment for improving wear resistance.
　このように構成される本実施の形態における粒子検出センサ３は、図２Ａ、図２Ｂ及び図２Ｃで説明したように、実施の形態１における粒子検出センサ１と同様の動作によって粒子を検出することができる。 As described in FIGS. 2A, 2B, and 2C, the particle detection sensor 3 in the present embodiment configured as described above detects particles by the same operation as the particle detection sensor 1 in the first embodiment. Can do.
　次に、本実施の形態における粒子検出センサ３の作用効果について、図１１Ａ及び図１１Ｂに示す比較例２の粒子検出センサ１００Ａと比較して説明する。図１１Ａは、比較例２の粒子検出センサ１００Ａの断面図であり、図１１Ｂは、図１１Ａに示す比較例２の粒子検出センサ１００Ａの内部を清掃するときの様子を示す同粒子検出センサ１００Ａの要部拡大断面図である。 Next, the operation and effect of the particle detection sensor 3 in the present embodiment will be described in comparison with the particle detection sensor 100A of Comparative Example 2 shown in FIGS. 11A and 11B. FIG. 11A is a cross-sectional view of the particle detection sensor 100A of Comparative Example 2, and FIG. 11B shows the state of cleaning the particle detection sensor 100A of Comparative Example 2 shown in FIG. 11A. It is a principal part expanded sectional view.
　光散乱式粒子検出センサでは、大気中に浮遊するホコリ・花粉・煙等の粒子を含む気体を内部に導入することによって粒子を検出するため、当該粒子が粒子検出センサの内部に付着物として付着して、検出精度が低下する場合がある。特に、長期にわたる使用によって付着物が内部に蓄積すると、検出誤差も大きくなる。例えば、粒子が存在しないはずなのに粒子が存在するものとして検知し、誤った判定をする場合がある。 In the light scattering type particle detection sensor, particles are detected by introducing gas containing particles such as dust, pollen and smoke floating in the atmosphere, so the particles adhere to the inside of the particle detection sensor. As a result, the detection accuracy may decrease. In particular, when deposits accumulate inside due to long-term use, detection errors also increase. For example, it may be detected that the particles are present even though the particles should not exist, and an erroneous determination may be made.
　そこで、図１１Ａに示すように、内部に付着した付着物を除去する構造を有する粒子検出センサ１００Ａが考えられている。 Therefore, as shown in FIG. 11A, a particle detection sensor 100A having a structure for removing deposits attached inside is considered.
　図１１Ａに示すように、比較例２の粒子検出センサ１００Ａは、投光素子１１０及び受光素子１２０と、投光素子１１０及び受光素子１２０を保持する筐体１３０と、投光領域１３１に配置されたレンズ１３１ａと、受光領域１３２に配置されたレンズ１３２ａとを備える。そして、粒子検出センサ１００Ａでは、内部を清掃できるように、筐体１３０に、検知対象の粒子を含む気体が流れる領域である気流通過領域に清掃具を導入するための貫通孔１７０が設けられている。 As shown in FIG. 11A, the particle detection sensor 100A of Comparative Example 2 is disposed in the light projecting element 110 and the light receiving element 120, the housing 130 that holds the light projecting element 110 and the light receiving element 120, and the light projecting area 131. The lens 131a and the lens 132a disposed in the light receiving region 132 are provided. And in particle | grain detection sensor 100A, the through-hole 170 for introduce | transducing a cleaning tool into the airflow passage area | region which is an area | region where the gas containing the particle | grains of detection object flows is provided in the housing | casing 130 so that the inside can be cleaned. Yes.
　比較例２の粒子検出センサ１００Ａにおいて、内部の清掃を行う場合、図１１Ｂに示すように、貫通孔１７０から綿棒等の清掃具２００を導入して、気流通過領域を構成する筐体３０の内壁等に付着した付着物を除去する。 In the particle detection sensor 100A of Comparative Example 2, when cleaning the inside, as shown in FIG. 11B, a cleaning tool 200 such as a cotton swab is introduced from the through-hole 170, and the inner wall of the housing 30 constituting the airflow passage region. Remove deposits that adhere to the surface.
　しかしながら、比較例２の粒子検出センサ１００Ａの構造では、受光領域１３２内に粒子が入り込んでしまうので、レンズ１３２ａに粒子が付着物として付着する。レンズ１３２ａは、粒子の散乱光を受光素子１２０に集光させるので、レンズ１３２ａに粒子が付着するとレンズ１３２ａのレンズ作用に影響を与えて受光感度が低下し、検出精度が低下する。 However, in the structure of the particle detection sensor 100A of Comparative Example 2, since particles enter the light receiving region 132, the particles adhere to the lens 132a as adhering matter. Since the lens 132a collects the scattered light of the particles on the light receiving element 120, if the particles adhere to the lens 132a, the lens function of the lens 132a is affected, the light receiving sensitivity is lowered, and the detection accuracy is lowered.
　また、レンズ１３２ａが受光領域１３２の奥まった箇所に配置されているので、レンズ１３２ａに粒子が付着すると、図１１Ｂに示すように貫通孔１７０から導入した清掃具では付着物を拭き取りにくい。つまり、貫通孔１７０の近傍部分の付着物は容易に拭き取ることができるものの、貫通孔１７０から離れた箇所に存在する付着物については拭き取ることが難しい。さらに、図１１Ｂに示すように、受光領域１３２の周辺部分は入り組んだ構造となっており角部分も多いので、当該角部分によって死角ができ、角部周辺に存在する付着物を拭き取ることが難しくなっている。 In addition, since the lens 132a is disposed in a deep part of the light receiving region 132, if particles adhere to the lens 132a, it is difficult to wipe off the deposit with a cleaning tool introduced from the through hole 170 as shown in FIG. 11B. That is, although the deposits in the vicinity of the through-hole 170 can be easily wiped off, it is difficult to wipe off deposits that are present away from the through-hole 170. Furthermore, as shown in FIG. 11B, since the peripheral portion of the light receiving region 132 has an intricate structure and has many corner portions, a blind spot is formed by the corner portions, and it is difficult to wipe off the deposits present around the corner portions. It has become.
　このように、比較例２の粒子検出センサ１００Ａでは、受光領域１３２内に付着した粒子によって検出精度が低下するという問題がある。 As described above, in the particle detection sensor 100A of Comparative Example 2, there is a problem that the detection accuracy is lowered due to the particles adhering in the light receiving region 132.
　ところで、受光感度を向上させるために、受光領域に、レンズではなく、回転楕円体等の回転面を反射面とする反射板（楕円ミラー等）を配置することも考えられているが、比較例２の粒子検出センサ１００Ａのように、筐体に貫通孔を設けて清掃具を導入する方法では、反射板の内面（反射面）の全面を清掃することが難しい。 By the way, in order to improve the light receiving sensitivity, it is considered that a reflecting plate (elliptical mirror or the like) having a rotating surface such as a spheroid instead of a lens is disposed in the light receiving region. In the method of providing a through-hole in the housing and introducing the cleaning tool like the particle detection sensor 100A of No. 2, it is difficult to clean the entire inner surface (reflecting surface) of the reflecting plate.
　このため、受光領域に反射板が配置された構成の粒子検出センサでは、反射板の内面に付着物が付着すると、受光素子に受光される粒子の散乱光の量（受光量）が大きく変わってしまう。この結果、検出精度が大きく低下してセンサとしての信頼性が悪くなる。 For this reason, in a particle detection sensor having a configuration in which a reflecting plate is arranged in the light receiving region, if an adhering material adheres to the inner surface of the reflecting plate, the amount of scattered light (the amount of received light) of the particles received by the light receiving element changes significantly. End up. As a result, the detection accuracy is greatly lowered and the reliability as the sensor is deteriorated.
　そこで、本実施の形態における粒子検出センサ３では、図１０（ｄ）に示すように、粒子流路３３と受光領域３２との接続部分に、透光性を有する第１保護板９１が配置されている。 Therefore, in the particle detection sensor 3 according to the present embodiment, as shown in FIG. 10D, a first protective plate 91 having translucency is disposed at a connection portion between the particle flow path 33 and the light receiving region 32. ing.
　これにより、ホコリ・花粉・煙等の粒子が受光領域３２の内部に入り込むことを抑制できるので、受光領域３２内にホコリ・花粉・煙等の粒子が付着物として付着することを抑制できる。したがって、受光領域３２に付着物が付着することによって検出精度が低下することを抑制できる。 Thereby, since particles such as dust, pollen and smoke can be prevented from entering the inside of the light receiving region 32, it is possible to suppress particles such as dust, pollen and smoke from adhering to the inside of the light receiving region 32. Therefore, it is possible to prevent the detection accuracy from being lowered due to the adhering matter adhering to the light receiving region 32.
　また、本実施の形態において、第１保護板９１は、受光領域３２の開口部（粒子流路３３との接続部分となる開口部）を覆うように配置されている。 Further, in the present embodiment, the first protective plate 91 is disposed so as to cover the opening of the light receiving region 32 (the opening serving as a connection portion with the particle channel 33).
　これにより、粒子が受光領域３２の内部に入り込むことを遮断できるので、受光領域３２内に粒子が付着することを回避できる。さらに、一旦、受光領域３２を第１保護板９１で覆った後は、その後の粒子検出センサ３の製造工程中においても受光領域３２に粒子等が入り込むことを遮断できるので、初期時の動作不良も防止できる。 Thereby, it is possible to prevent the particles from entering the inside of the light receiving region 32, and thus it is possible to avoid the particles from adhering in the light receiving region 32. Furthermore, once the light receiving area 32 is covered with the first protective plate 91, it is possible to block particles and the like from entering the light receiving area 32 even during the subsequent manufacturing process of the particle detection sensor 3, so that the initial operation failure Can also be prevented.
　また、本実施の形態において、第１保護板９１と受光素子２０との間に、粒子の散乱光を反射して当該散乱光を受光素子２０に導く反射体４０が設けられている。例えば、反射体４０の内面は、回転楕円体の回転面の一部であり、楕円ミラーである。 In the present embodiment, a reflector 40 is provided between the first protective plate 91 and the light receiving element 20 to reflect the scattered light of the particles and guide the scattered light to the light receiving element 20. For example, the inner surface of the reflector 40 is a part of the rotation surface of the spheroid and is an elliptical mirror.
　これにより、粒子の付着によって反射体４０の反射面が汚れることを抑制できる。つまり、反射体４０の反射面に粒子等の付着物が蓄積されない。したがって、反射体４０の反射面の反射率が長期にわたって変化しないので、受光感度及び検出精度の長期信頼性を向上させることができる。 Thereby, it can suppress that the reflective surface of the reflector 40 becomes dirty by adhesion of particle | grains. That is, deposits such as particles are not accumulated on the reflection surface of the reflector 40. Therefore, since the reflectance of the reflecting surface of the reflector 40 does not change over a long period, the long-term reliability of the light receiving sensitivity and the detection accuracy can be improved.
　さらに、第１保護板９１によって受光領域３２を密閉することによって、受光領域３２に空気や水分が入り込むことも遮断できる。これにより、反射体４０の反射面が腐食することを防止できるので、受光感度及び検出精度の長期信頼性を一層向上させることができる。 Furthermore, by sealing the light receiving area 32 with the first protective plate 91, it is possible to block air and moisture from entering the light receiving area 32. Thereby, since it can prevent that the reflective surface of the reflector 40 corrodes, long-term reliability of a light reception sensitivity and a detection accuracy can be improved further.
　また、本実施の形態において、第１保護板９１の主面は、反射体４０の内面を構成する回転楕円体の楕円の長軸に対して直角である。 In the present embodiment, the main surface of the first protective plate 91 is perpendicular to the major axis of the ellipsoid of the spheroid constituting the inner surface of the reflector 40.
　これにより、検知領域ＤＡにおける粒子の散乱光を効率良く第１保護板９１を透過させることができるので、第１保護板９１を配置したことで受光感度が低下することをなくすことができる。 Thereby, the scattered light of the particles in the detection area DA can be efficiently transmitted through the first protective plate 91, so that the light receiving sensitivity can be prevented from being lowered by arranging the first protective plate 91.
　また、本実施の形態において、粒子流路３３の幅と検知領域ＤＡの幅とを一致させるとよい。 In the present embodiment, the width of the particle flow path 33 and the width of the detection area DA may be matched.
　これにより、粒子検知センサ３内に導入される粒子を含んだ気体の全てが検知領域ＤＡを通過することになるので、取り込まれた気体中に含まれる粒子を全て検出することができる。したがって、粒子の検出確率が向上し、検出精度を向上させることができる。 Thereby, since all of the gas containing the particles introduced into the particle detection sensor 3 passes through the detection area DA, all the particles contained in the taken-in gas can be detected. Therefore, the detection probability of particles can be improved and the detection accuracy can be improved.
　（実施の形態３の変形例１）
　次に、実施の形態３の変形例１に係る粒子検出センサ３Ａについて、図１２を用いて説明する。図１２は、実施の形態３の変形例１に係る粒子検出センサ３Ａの構成を示す断面図である。 (Modification 1 of Embodiment 3)
Next, a particle detection sensor 3A according to Modification 1 of Embodiment 3 will be described with reference to FIG. FIG. 12 is a cross-sectional view showing a configuration of a particle detection sensor 3A according to Modification 1 of Embodiment 3.
　図１２に示すように、本変形例における粒子検出センサ３Ａと上記実施の形態３における粒子検出センサ３とは、第１保護板９１の配置が異なる。 As shown in FIG. 12, the arrangement of the first protective plate 91 is different between the particle detection sensor 3A in the present modification and the particle detection sensor 3 in the third embodiment.
　具体的には、上記実施の形態３における第１保護板９１は、その主面が反射体４０を構成する楕円の長軸に対して直角となるように配置されていたのに対して、本変形例における第１保護板９１は、その主面の法線が反射体４０を構成する楕円の長軸に対して傾斜するように配置されている。 Specifically, the first protective plate 91 according to the third embodiment is arranged so that its main surface is perpendicular to the major axis of the ellipse that constitutes the reflector 40. The first protective plate 91 in the modified example is disposed so that the normal line of the main surface thereof is inclined with respect to the major axis of the ellipse constituting the reflector 40.
　以上、本変形例における粒子検出センサ３Ａによれば、実施の形態３における粒子検出センサ３と同様に、粒子流路３３と受光領域３２との接続部分に第１保護板９１が配置されているので、粒子検出センサ３Ａの動作中においても粒子検出センサ３Ａの製造工程中においても、受光領域３２内に粒子が付着することを抑制できる。したがって、検出精度の低下を抑制できる。 As described above, according to the particle detection sensor 3 </ b> A in the present modification, the first protective plate 91 is arranged at the connection portion between the particle flow path 33 and the light receiving region 32, similarly to the particle detection sensor 3 in the third embodiment. Therefore, it is possible to suppress the adhesion of particles in the light receiving region 32 both during the operation of the particle detection sensor 3A and during the manufacturing process of the particle detection sensor 3A. Therefore, a decrease in detection accuracy can be suppressed.
　また、本変形例でも、第１保護板９１が受光領域３２の開口部を覆うように配置されているので、受光領域３２内に粒子が付着することを一層抑制できる。 Also in this modified example, since the first protective plate 91 is disposed so as to cover the opening of the light receiving region 32, it is possible to further suppress the adhesion of particles in the light receiving region 32.
　また、本変形例でも、粒子の付着によって反射体４０の反射面が汚れることを抑制できるので、反射体４０の反射面の反射率が変化せず、受光感度及び検出精度の長期信頼性を向上させることができる。 Also in this modified example, it is possible to prevent the reflecting surface of the reflector 40 from becoming dirty due to the adhesion of particles, so that the reflectance of the reflecting surface of the reflector 40 does not change, and the long-term reliability of light receiving sensitivity and detection accuracy is improved. Can be made.
　さらに、第１保護板９１によって受光領域３２を密閉することによって、受光領域３２に空気や水分が入り込むことを遮断することができる。これにより、反射体４０の反射面の腐食を防止できるので、受光感度及び検出精度の長期信頼性を一層向上させることができる。 Further, by sealing the light receiving area 32 with the first protective plate 91, it is possible to prevent air and moisture from entering the light receiving area 32. Thereby, since corrosion of the reflective surface of the reflector 40 can be prevented, the long-term reliability of the light receiving sensitivity and detection accuracy can be further improved.
　また、本変形例では、第１保護板９１の主面の法線が、反射体４０の回転楕円体を構成する楕円の長軸に対して傾斜している。 In this modification, the normal line of the main surface of the first protective plate 91 is inclined with respect to the major axis of the ellipse that constitutes the spheroid of the reflector 40.
　これにより、反射体４０の開口部を受光領域３２の開口部のぎりぎりまで延ばしたりして反射体４０の反射面を多く取ることができるので、反射体４０における粒子の散乱光の受光感度を容易に高くすることができる。したがって、高感度で粒子の検出を行うことができる粒子検出センサを実現できる。 Thereby, since the opening part of the reflector 40 can be extended to the limit of the opening part of the light-receiving region 32, a large number of reflection surfaces of the reflector 40 can be obtained, and thus the light-receiving sensitivity of the scattered light of the particles in the reflector 40 is easy. Can be high. Therefore, a particle detection sensor that can detect particles with high sensitivity can be realized.
　（実施の形態３の変形例２）
　次に、実施の形態３の変形例２に係る粒子検出センサ３Ｂについて、図１３を用いて説明する。図１３は、実施の形態３の変形例２に係る粒子検出センサ３Ｂの構成を示す断面図である。 (Modification 2 of Embodiment 3)
Next, a particle detection sensor 3B according to Modification 2 of Embodiment 3 will be described with reference to FIG. FIG. 13 is a cross-sectional view showing a configuration of a particle detection sensor 3B according to Modification 2 of Embodiment 3.
　図１３に示すように、本変形例における粒子検出センサ３Ｂと上記実施の形態３における粒子検出センサ３とは、第１保護板９１の配置が異なる。 As shown in FIG. 13, the arrangement of the first protective plate 91 is different between the particle detection sensor 3B in the present modification and the particle detection sensor 3 in the third embodiment.
　すなわち、上記実施の形態３における第１保護板９１は、粒子流路３３と受光領域３２との接続部分のみに配置されていたのに対して、本変形例における第１保護板９１は、粒子流路３３と受光領域３２との接続部分だけではなく粒子流路３３とトラップ部３４との接続部分にも配置されている。具体的には、本変形例における第１保護板９１は、受光領域３２の開口部とトラップ部３４の開口部との両方を覆っている。 That is, the first protective plate 91 in the third embodiment is disposed only in the connection portion between the particle flow path 33 and the light receiving region 32, whereas the first protective plate 91 in the present modification is a particle It is arranged not only at the connection part between the flow path 33 and the light receiving region 32 but also at the connection part between the particle flow path 33 and the trap part 34. Specifically, the first protective plate 91 in the present modification covers both the opening of the light receiving region 32 and the opening of the trap portion 34.
　また、第１保護板９１は、粒子流路３３の一部を構成している。具体的には、第１保護板９１の表面は粒子流路３３の壁面となっている。 Further, the first protective plate 91 constitutes a part of the particle flow path 33. Specifically, the surface of the first protective plate 91 is a wall surface of the particle channel 33.
　以上、本変形例における粒子検出センサ３Ｂによれば、粒子流路３３と受光領域３２との接続部分及び粒子流路３３と受光領域３２との接続部分に第１保護板９１が配置されている。 As described above, according to the particle detection sensor 3 </ b> B in the present modification, the first protective plate 91 is disposed at the connection portion between the particle flow path 33 and the light receiving region 32 and at the connection portion between the particle flow path 33 and the light receiving region 32. .
　これにより、大気中に浮遊する粒子が受光領域３２だけではなくもトラップ部３４にも入り込まないようにすることができるので、粒子検出センサ３Ｂの動作中においても粒子検出センサ３Ｂの製造工程中においても、受光領域３２内及びトラップ部３４内に粒子が付着することを抑制できる。したがって、検出精度の低下を抑制できる。 As a result, it is possible to prevent particles floating in the atmosphere from entering not only the light receiving region 32 but also the trap part 34. Therefore, even during the operation of the particle detection sensor 3B, during the manufacturing process of the particle detection sensor 3B. In addition, it is possible to suppress the adhesion of particles in the light receiving region 32 and the trap portion 34. Therefore, a decrease in detection accuracy can be suppressed.
　また、本変形例でも、粒子の付着によって反射体４０の反射面が汚れることを抑制できるので、反射体４０の反射面の反射率が変化せず、受光感度及び検出精度の長期信頼性を向上させることができる。しかも、反射体４０によってトラップ部３４の反射率も変わらないので、粒子に当たらすに検知領域ＤＡを通過する投光素子１０からの直接光が筐体３０内部で反射して迷光となって受光素子２０に入射することも抑制できる。したがって、受光感度及び検出精度の長期信頼性を一層向上させることができる。 Also in this modified example, it is possible to prevent the reflecting surface of the reflector 40 from becoming dirty due to the adhesion of particles, so that the reflectance of the reflecting surface of the reflector 40 does not change, and the long-term reliability of light receiving sensitivity and detection accuracy is improved. Can be made. Moreover, since the reflectance of the trap part 34 does not change by the reflector 40, the direct light from the light projecting element 10 that passes through the detection area DA when hitting the particles is reflected inside the housing 30 and received as stray light. It can also suppress entering into the element 20. FIG. Therefore, the long-term reliability of the light receiving sensitivity and detection accuracy can be further improved.
　この場合、第１保護板９１によって受光領域３２及びトラップ部３４を密閉することによって、受光領域３２及びトラップ部３４に空気や水分が入り込むことを遮断することができる。これにより、反射体４０の反射面の腐食とトラップ部３４の劣化とを防止できるので、受光感度及び検出精度の長期信頼性を一層向上させることができる。 In this case, air and moisture can be prevented from entering the light receiving region 32 and the trap part 34 by sealing the light receiving region 32 and the trap part 34 with the first protective plate 91. Thereby, since corrosion of the reflective surface of the reflector 40 and deterioration of the trap part 34 can be prevented, the long-term reliability of light receiving sensitivity and detection accuracy can be further improved.
　また、本変形例では、粒子の付着によってトラップ部３４内も汚れないので、センサとしての信頼性が向上するとともに歩留まりが向上する。 Further, in this modification, the trap portion 34 is not contaminated by the adhesion of particles, so that the reliability as a sensor is improved and the yield is improved.
　（実施の形態３の変形例３）
　次に、実施の形態３の変形例３に係る粒子検出センサ３Ｃについて、図１４を用いて説明する。図１４は、実施の形態３の変形例３に係る粒子検出センサ３Ｃの構成を示す断面図である。 (Modification 3 of Embodiment 3)
Next, a particle detection sensor 3C according to Modification 3 of Embodiment 3 will be described with reference to FIG. FIG. 14 is a cross-sectional view illustrating a configuration of a particle detection sensor 3C according to Modification 3 of Embodiment 3.
　図１４に示すように、本変形例における粒子検出センサ３Ｃは、上記変形例２における粒子検出センサ３Ｂにおいて、さらに、第２保護板９２が配置された構成となっている。 As shown in FIG. 14, the particle detection sensor 3 </ b> C in the present modification has a configuration in which a second protection plate 92 is further arranged in the particle detection sensor 3 </ b> B in the modification 2 described above.
　具体的には、本変形例における粒子検出センサ３Ｃは、受光領域３２及びトラップ部３４の開口部を覆うように配置された第１保護板９１と、投光領域３１と粒子流路３３との接続部分に配置された第２保護板９２とを有する。 Specifically, the particle detection sensor 3 </ b> C according to the present modification includes a first protection plate 91 disposed so as to cover the light receiving region 32 and the opening of the trap portion 34, the light projecting region 31, and the particle flow path 33. And a second protection plate 92 disposed in the connection portion.
　本変形例において、第２保護板９２は、第１保護板９１と対面するように配置されている。つまり、第２保護板９２と第１保護板９１とは、平行に配置されている。 In the present modification, the second protective plate 92 is disposed so as to face the first protective plate 91. That is, the second protection plate 92 and the first protection plate 91 are arranged in parallel.
　第２保護板９２は、投光領域３１に粒子が入り込まないようにするための保護部材である。具体的には、第２保護板９２は、投光領域３１の粒子流路３３との接続部分となる開口部（投光領域３１の開口部）を覆うように配置されている。つまり、第２保護板９２は投光領域３１に蓋をするように配置されており、投光領域３１の開口部が第２保護板９２で覆われることによって投光領域３１は閉じた空間領域となる。 The second protective plate 92 is a protective member for preventing particles from entering the light projecting region 31. Specifically, the second protective plate 92 is disposed so as to cover an opening (an opening of the light projecting region 31) serving as a connection portion between the light projecting region 31 and the particle flow path 33. In other words, the second protective plate 92 is disposed so as to cover the light projecting region 31, and the light projecting region 31 is closed by covering the opening of the light projecting region 31 with the second protective plate 92. It becomes.
　また、第２保護板９２は、第１保護板９１ともに、粒子流路３３の一部を構成している。具体的には、第１保護板９１及び第２保護板９２の表面は粒子流路３３の壁面となっており、粒子流路３３に導入された粒子は、第１保護板９１及び第２保護板９２の間を通過する。 Also, the second protective plate 92 and the first protective plate 91 constitute a part of the particle flow path 33. Specifically, the surfaces of the first protective plate 91 and the second protective plate 92 are wall surfaces of the particle flow path 33, and the particles introduced into the particle flow path 33 are the first protective plate 91 and the second protective plate. Passes between the plates 92.
　第２保護板９２は、第１保護板９１と同様に、例えばガラスや透明樹脂によって構成された透明板であって、全透過率はフレネル反射を無視すれば例えば９９％以上である。また、第２保護板９２としては、厚みが一様の平板を用いている。なお、第２保護板９２は、厚みが一様の平板でなくてもよく、第１保護板９１と同様に、取付上、周縁部分が肉薄となっていたり周縁部分の一部が切り欠かれていたりしてもよい。 Similarly to the first protective plate 91, the second protective plate 92 is a transparent plate made of, for example, glass or transparent resin, and the total transmittance is, for example, 99% or more if the Fresnel reflection is ignored. Further, a flat plate having a uniform thickness is used as the second protective plate 92. Note that the second protective plate 92 may not be a flat plate having a uniform thickness. Like the first protective plate 91, the peripheral portion is thin or a part of the peripheral portion is notched for mounting. It may be.
　第２保護板９２の平面視形状は、投光領域３１の開口部を覆う形状であればよく、例えば、投光領域３１の開口部の形状が円形である場合は、第２保護板９２としては円板状の透明板を用いればよい。 The shape of the second protective plate 92 in plan view may be a shape that covers the opening of the light projecting region 31. For example, when the shape of the opening of the light projecting region 31 is circular, the second protective plate 92 serves as the second protective plate 92. A disc-shaped transparent plate may be used.
　また、第２保護板９２も、粒子の散乱光を散乱させないように構成されている。つまり、第２保護板９２で光が散乱しないように、第２保護板９２の表面は、検知領域ＤＡ側の主面も投光素子１０側の主面も平滑面である。 The second protective plate 92 is also configured not to scatter the scattered light of the particles. That is, the surface of the second protective plate 92 is a smooth surface on both the main surface on the detection area DA side and the main surface on the light projecting element 10 side so that light is not scattered by the second protective plate 92.
　なお、後述するように、第２保護板９２の表面に付着した付着物を綿棒等の清掃具で擦って除去することもあるので、第２保護板９２の表面は、耐摩耗性を有するとよい。したがって、第２保護板９２の表面には、耐摩耗性を向上させるための表面処理又は表面コート処理等が施されているとよい。 As will be described later, since the adhering matter adhering to the surface of the second protective plate 92 may be removed by rubbing with a cleaning tool such as a cotton swab, the surface of the second protective plate 92 has wear resistance. Good. Therefore, the surface of the second protective plate 92 is preferably subjected to surface treatment or surface coating treatment for improving wear resistance.
　以上、本変形例における粒子検出センサ３Ｃによれば、粒子流路３３と受光領域３２との接続部分及び粒子流路３３と受光領域３２との接続部分に第１保護板９１が配置されているので、実施の形態３の変形例２と同様の効果が得られる。 As described above, according to the particle detection sensor 3 </ b> C in the present modification, the first protective plate 91 is disposed at the connection portion between the particle flow path 33 and the light receiving region 32 and at the connection portion between the particle flow path 33 and the light receiving region 32. Therefore, the same effect as that of the second modification of the third embodiment can be obtained.
　さらに、本変形例では、投光領域３１と粒子流路３３との接続部分に第２保護板９２が配置されている。 Furthermore, in the present modification, a second protective plate 92 is disposed at the connection portion between the light projecting region 31 and the particle flow path 33.
　これにより、大気中に浮遊する粒子が投光領域３１にも入り込まないようにすることができ、投光領域３１内に粒子が付着することを抑制できるとともに、投光レンズ３１ａ及び発光絞り部３１ｂに粒子が付着することも抑制できる。したがって、投光素子１０からの出射光を安定させることができるので、センサとしての信頼性が向上する。 Thereby, it is possible to prevent particles floating in the atmosphere from entering the light projecting region 31 and to prevent particles from adhering to the light projecting region 31, and to use the light projecting lens 31a and the light emission diaphragm 31b. It is also possible to suppress adhesion of particles to the surface. Therefore, since the emitted light from the light projecting element 10 can be stabilized, the reliability as a sensor is improved.
　また、投光領域３１が第２保護板９２で覆われているので、投光レンズ３１ａを投光領域３１の奥まった位置に配置することができ、投光レンズ３１ａの設計の自由度が高まる。つまり、メンテナンスの際に投光レンズ３１ａに付着した粒子等を拭き取りやすくするためだけに、投光レンズ３１ａを粒子流路３３に近い位置に配置する必要がない。 Moreover, since the light projection area | region 31 is covered with the 2nd protection board 92, the light projection lens 31a can be arrange | positioned in the back position of the light projection area | region 31, and the freedom degree of design of the light projection lens 31a increases. . That is, it is not necessary to dispose the light projecting lens 31a at a position close to the particle flow path 33 only to facilitate wiping off particles and the like attached to the light projecting lens 31a during maintenance.
　また、第１保護板９１と第２保護板９２とで形成される空間は、粒子流路３３の一部を形成し、且つ、検知領域ＤＡの幅と一致するとよい。例えば、第１保護板９１と第２保護板９２とで挟まれる空間が粒子流路３３の一部となるように構成し、且つ、第１保護板９１と第２保護板９２との間隔を粒子流路３３の幅に一致させるとともに検知領域ＤＡの幅に一致させるとよい。 Also, the space formed by the first protective plate 91 and the second protective plate 92 may form a part of the particle flow path 33 and coincide with the width of the detection area DA. For example, the space between the first protective plate 91 and the second protective plate 92 is configured to be a part of the particle flow path 33, and the distance between the first protective plate 91 and the second protective plate 92 is set. The width of the particle flow path 33 is preferably matched with the width of the detection area DA.
　これにより、粒子検知センサ３Ｃ内に導入される粒子を含んだ気体の全てが、検知領域ＤＡの幅と一致した粒子流路３３を通過するので、取り込まれた気体中に含まれる粒子を全て検出することができる。したがって、粒子の検出確率が向上し、検出精度を向上させることができる。 As a result, all of the gas containing particles introduced into the particle detection sensor 3C passes through the particle flow path 33 that matches the width of the detection area DA, so that all the particles contained in the taken-in gas are detected. can do. Therefore, the detection probability of particles can be improved and the detection accuracy can be improved.
　（実施の形態３の変形例４）
　次に、実施の形態３の変形例４に係る粒子検出センサ３Ｄについて、図１５を用いて説明する。図１５は、実施の形態３の変形例４に係る粒子検出センサ３Ｄの構成を示す断面図であり、（ａ）は上面図、（ｂ）は正面図、（ｃ）は下面図、（ｄ）は（ａ）のＡ－Ａ線における断面図である。 (Modification 4 of Embodiment 3)
Next, a particle detection sensor 3D according to Modification 4 of Embodiment 3 will be described with reference to FIG. FIG. 15 is a cross-sectional view illustrating a configuration of a particle detection sensor 3D according to Modification 4 of Embodiment 3, where (a) is a top view, (b) is a front view, (c) is a bottom view, and (d). ) Is a sectional view taken along line AA in FIG.
　図１５（ｂ）に示すように、本変形例における粒子検出センサ３Ｄは、上記実施の形態３の変形例３における粒子検出センサ３Ｃにおいて、さらに、筐体３０は、第１保護板９１及び第２保護板９２の表面に付着した付着物を除去するための清掃具が導入される清掃具導入孔３７と、清掃具導入孔３７を閉じる蓋３８とを有する。 As shown in FIG. 15B, the particle detection sensor 3D in the present modification is the same as the particle detection sensor 3C in the third modification of the third embodiment, and the housing 30 further includes the first protection plate 91 and the first protection plate 91. 2 It has the cleaning tool introduction hole 37 into which the cleaning tool for removing the deposit | attachment adhering to the surface of the protective plate 92 is introduced, and the lid | cover 38 which closes the cleaning tool introduction hole 37.
　具体的には、清掃具導入孔３７は、第１筐体部３０ａに設けられた貫通孔である。清掃具導入孔３７は、清掃具を第１保護板９１及び第２保護板９２の主面水平方向から挿入できるように構成されている。本変形例において、清掃具導入孔３７は、第１保護板９１及び第２保護板９２の主面水平方向を開放するように設けられており、より具体的には、第１筐体部３０ａの第１保護板９１及び第２保護板９２に対向する部分を開口するように設けられている。つまり、清掃具導入孔３７は、粒子流路３３の一部を開口している。さらに、清掃具導入孔３７は、大気が粒子流路３３内を流れる方向（流路方向）に沿って長尺状に設けられている。 Specifically, the cleaning tool introduction hole 37 is a through hole provided in the first housing portion 30a. The cleaning tool introduction hole 37 is configured such that the cleaning tool can be inserted from the horizontal direction of the main surfaces of the first protection plate 91 and the second protection plate 92. In this modification, the cleaning tool introduction hole 37 is provided so as to open the main surface horizontal direction of the first protective plate 91 and the second protective plate 92, and more specifically, the first housing portion 30a. The first protection plate 91 and the second protection plate 92 are provided so as to open portions facing each other. That is, the cleaning tool introduction hole 37 opens a part of the particle flow path 33. Further, the cleaning tool introduction hole 37 is provided in a long shape along the direction in which the air flows in the particle flow path 33 (flow path direction).
　第１保護板９１及び第２保護板９２を清掃する以外（粒子検出センサ３Ｄが動作中）は、清掃具導入孔３７は蓋３８によって塞がれている。蓋３８は、清掃具導入孔３７に着脱可能に嵌め込まれている。したがって、第１保護板９１及び第２保護板９２等の筐体３０内を清掃する場合、蓋３８を取り外して清掃具導入孔３７を開放し、清掃具導入孔３７から綿棒等の清掃具を挿入して筐体３０内の清掃を行う。 Except for cleaning the first protection plate 91 and the second protection plate 92 (when the particle detection sensor 3D is operating), the cleaning tool introduction hole 37 is blocked by the lid 38. The lid 38 is detachably fitted in the cleaning tool introduction hole 37. Therefore, when cleaning the inside of the housing 30 such as the first protection plate 91 and the second protection plate 92, the lid 38 is removed to open the cleaning tool introduction hole 37, and a cleaning tool such as a cotton swab is removed from the cleaning tool introduction hole 37. Insert and clean the inside of the housing 30.
　以上、本変形例に係る粒子検出センサ３Ｄによれば、清掃具導入孔３７を利用することによって、筐体３０内に付着した粒子等の付着物を除去するためのメンテナンスを行うことができる。例えば、第１保護板９１及び第２保護板９２の表面や粒子流路３３の壁面、あるいは、その他の筐体３０内の壁面に付着した付着物を除去することができる。 As described above, according to the particle detection sensor 3 </ b> D according to the present modification, by using the cleaning tool introduction hole 37, it is possible to perform maintenance for removing adhered substances such as particles adhered in the housing 30. For example, deposits attached to the surfaces of the first protection plate 91 and the second protection plate 92, the wall surface of the particle flow path 33, or other wall surfaces in the housing 30 can be removed.
　この場合、図１６Ａ及び図１６Ｂに示すように、清掃具導入孔３７から綿棒等の清掃具２００を導入して、第１保護板９１及び第２保護板９２の表面（粒子流路３３側の面）を清掃具２００で擦る等することによって第１保護板９１及び第２保護板９２の表面に付着した付着物を拭き取ることができる。図１６Ａ及び図１６Ｂは、本変形例に係る粒子検出センサ３Ｄの筐体内を清掃（メンテナンス）するときの様子を示している。 In this case, as shown in FIGS. 16A and 16B, a cleaning tool 200 such as a cotton swab is introduced from the cleaning tool introduction hole 37, and the surfaces of the first protection plate 91 and the second protection plate 92 (on the particle flow path 33 side). The adhering matter adhering to the surfaces of the first protective plate 91 and the second protective plate 92 can be wiped off by rubbing the surface) with the cleaning tool 200 or the like. FIG. 16A and FIG. 16B show a state when the inside of the housing of the particle detection sensor 3D according to the present modification is cleaned (maintenance).
　また、図１５に示すように、本変形例では、清掃具導入孔３７が第１保護板９１及び第２保護板９２と対向する位置に設けられているので、清掃具導入孔３７から挿入した清掃具２００によって第１保護板９１及び第２保護板９２の表面に付着した付着物を容易に除去することができる。 Further, as shown in FIG. 15, in this modified example, the cleaning tool introduction hole 37 is provided at a position facing the first protection plate 91 and the second protection plate 92, so that it is inserted from the cleaning tool introduction hole 37. The cleaning tool 200 can easily remove deposits attached to the surfaces of the first protection plate 91 and the second protection plate 92.
　また、本変形例において、清掃具導入孔３７は、清掃具２００を第１保護板９１及び第２保護板９２の主面水平方向から挿入できるように構成されている。これにより、清掃具導入孔３７に綿棒等の清掃具２００を挿入する際、第１保護板９１及び第２保護板９２の主面水平方向から清掃具２００を挿入することができる。 In this modification, the cleaning tool introduction hole 37 is configured so that the cleaning tool 200 can be inserted from the horizontal direction of the main surface of the first protection plate 91 and the second protection plate 92. Accordingly, when the cleaning tool 200 such as a cotton swab is inserted into the cleaning tool introduction hole 37, the cleaning tool 200 can be inserted from the horizontal direction of the main surfaces of the first protection plate 91 and the second protection plate 92.
　そして、図１６Ａ及び図１６Ｂに示すように、例えば、清掃具導入孔３７に挿入した清掃具２００によって第１保護板９１及び第２保護板９２の表面を擦るようにして、当該清掃具２００を清掃具２００の挿入方向に垂直な方向に沿って前後に動かすことで、第１保護板９１及び第２保護板９２の表面の付着物を拭き取ることができる。なお、第１保護板９１及び第２保護板９２の付着物を擦り取る際の清掃具２００の移動方向は、清掃具２００の挿入方向に垂直な方向に限るものではなく、清掃具２００の挿入方向等であってもよい。 Then, as shown in FIGS. 16A and 16B, for example, the cleaning tool 200 is rubbed against the surfaces of the first protection plate 91 and the second protection plate 92 by the cleaning tool 200 inserted into the cleaning tool introduction hole 37. By moving the cleaning tool 200 back and forth along the direction perpendicular to the insertion direction of the cleaning tool 200, the deposits on the surfaces of the first protection plate 91 and the second protection plate 92 can be wiped off. In addition, the moving direction of the cleaning tool 200 when scraping off the deposits on the first protection plate 91 and the second protection plate 92 is not limited to the direction perpendicular to the insertion direction of the cleaning tool 200. It may be a direction or the like.
　また、本変形例において、清掃具導入孔３７は、第１保護板９１及び第２保護板９２の主面水平方向を開放する位置に設けられている。これにより、清掃具２００を、清掃具導入孔３７を介して第１保護板９１及び第２保護板９２の主面水平方向から筐体３０内に容易に挿入することができる。 Further, in the present modification, the cleaning tool introduction hole 37 is provided at a position where the main surface horizontal direction of the first protection plate 91 and the second protection plate 92 is opened. Thereby, the cleaning tool 200 can be easily inserted into the housing 30 from the horizontal direction of the main surfaces of the first protection plate 91 and the second protection plate 92 via the cleaning tool introduction hole 37.
　また、本変形例において、清掃具導入孔３７は、大気が粒子流路３３内を流れる方向に沿って長尺状に設けられている。これにより、清掃具導入孔３７に挿入した清掃具２００を粒子流路３３の流路方向に沿って前後に動かすことによって、第１保護板９１及び第２保護板９２の主面の付着物を容易に拭き取ることができる。 Further, in the present modification, the cleaning tool introduction hole 37 is provided in a long shape along the direction in which the air flows in the particle flow path 33. As a result, the cleaning tool 200 inserted into the cleaning tool introduction hole 37 is moved back and forth along the flow path direction of the particle flow path 33, thereby adhering substances on the main surfaces of the first protection plate 91 and the second protection plate 92. Can be easily wiped off.
　また、本変形例において、清掃具導入孔３７は、当該清掃具導入孔３７に着脱可能に取り付けられた蓋３８によって塞がれている。これにより、第１保護板９１及び第２保護板９２を清掃するときだけ蓋３８を外せばよく、清掃するとき以外は清掃具導入孔３７を蓋３８で閉じることができる。したがって、粒子検出センサ３Ｄ本来のセンサ機能に影響を与えることなく、清掃（メンテナンス）を行うことができる。 In this modification, the cleaning tool introduction hole 37 is closed by a lid 38 that is detachably attached to the cleaning tool introduction hole 37. Thereby, it is only necessary to remove the lid 38 only when cleaning the first protective plate 91 and the second protective plate 92, and the cleaning tool introduction hole 37 can be closed with the lid 38 except when cleaning. Therefore, cleaning (maintenance) can be performed without affecting the original sensor function of the particle detection sensor 3D.
　なお、本変形例は、実施の形態３及びその変形例１～３にも適用することができる。この場合、第１保護板９１の表面に付着した付着物を除去するために、清掃具導入孔３７には清掃具２００が挿入される。 It should be noted that this modification can also be applied to the third embodiment and its modifications 1 to 3. In this case, the cleaning tool 200 is inserted into the cleaning tool introduction hole 37 in order to remove deposits attached to the surface of the first protective plate 91.
　（変形例）
　以下、本発明の変形例に係る粒子検出センサについて、図面を参照しながら説明する。なお、以下に説明する変形例では、主要な構成のみを図示しており、筐体等のその他の構成は、各変形例の態様に応じて適宜変更できるので、図示していない。 (Modification)
Hereinafter, a particle detection sensor according to a modification of the present invention will be described with reference to the drawings. In the modification described below, only the main configuration is illustrated, and other configurations such as a housing can be appropriately changed according to the mode of each modification and are not illustrated.
　（変形例１）
　図１７は、変形例１に係る粒子検出センサ１Ａの概略構成を示す断面図である。 (Modification 1)
FIG. 17 is a cross-sectional view illustrating a schematic configuration of a particle detection sensor 1A according to the first modification.
　図１７に示すように、本変形例における粒子検出センサ１Ａは、上記実施の形態１における粒子検出センサ１と同様に、投光素子１０と投光レンズ３１ａと受光素子２０と反射体４０Ａと加熱装置（不図示）とを備えており、検知領域ＤＡにおける粒子による投光素子１０の光の散乱光を受光素子２０で受光することにより気体中に含まれる粒子を検出する。 As shown in FIG. 17, the particle detection sensor 1A according to the present modification is similar to the particle detection sensor 1 according to the first embodiment, in which the light projecting element 10, the light projecting lens 31a, the light receiving element 20, the reflector 40A, and the heating are performed. And a device (not shown). The light receiving element 20 receives the scattered light of the light of the light projecting element 10 due to the particles in the detection area DA, thereby detecting particles contained in the gas.
　本変形例における反射体４０Ａは、上記実施の形態１における反射体４０と同様に、内面が回転楕円体の回転面の一部をなしている。さらに、反射体４０Ａの側部には、２つの貫通孔４１ａ及び４１ｂが設けられている。 The reflector 40A in the present modification has an inner surface that forms part of the rotational surface of the spheroid, similar to the reflector 40 in the first embodiment. Further, two through holes 41a and 41b are provided on the side of the reflector 40A.
　本変形例において、検知領域ＤＡが存在する粒子流路３３の流路方向は紙面垂直方向であり、粒子流路３３にはヒータ抵抗等の加熱装置が設置されている。 In this modification, the flow path direction of the particle flow path 33 in which the detection area DA exists is a direction perpendicular to the paper surface, and a heating device such as a heater resistor is installed in the particle flow path 33.
　また、投光素子１０及び投光レンズ３１ａは、貫通孔４１ａと対向するように配置されており、投光素子１０及び投光レンズ３１ａの光軸と２つの貫通孔４１ａ及び４１ｂの中心軸とが一致している。投光素子１０から出射する光は、貫通孔４１ａを通過して反射体４０Ａの内方部分に設定された検知領域ＤＡに投光される。また、投光素子１０の光のうち粒子に当たらずに直進する光は、貫通孔４１ｂを通過して反射体４０Ａの外部に抜けるので、受光素子２０に入射しない。 The light projecting element 10 and the light projecting lens 31a are arranged so as to face the through hole 41a, and the optical axis of the light projecting element 10 and the light projecting lens 31a and the central axes of the two through holes 41a and 41b are arranged. Match. The light emitted from the light projecting element 10 passes through the through hole 41a and is projected onto the detection area DA set in the inner part of the reflector 40A. In addition, light that travels straight without hitting particles out of the light from the light projecting element 10 passes through the through hole 41 b and goes out of the reflector 40 </ b> A, and therefore does not enter the light receiving element 20.
　以上、本変形例における粒子検出センサ１Ａによれば、検知領域ＤＡにおける粒子の散乱光を反射して当該散乱光を受光素子２０に導く反射体４０Ａを備えている。 As described above, the particle detection sensor 1 </ b> A according to the present modification includes the reflector 40 </ b> A that reflects the scattered light of the particles in the detection area DA and guides the scattered light to the light receiving element 20.
　これにより、上記実施の形態と同様に、加熱装置（不図示）を用いた加熱方式の粒子検出センサであっても、気体中に含まれる粒径の小さな粒子を高精度で検出することができる。 As a result, similarly to the above embodiment, even a heating type particle detection sensor using a heating device (not shown) can detect particles with a small particle size contained in gas with high accuracy. .
　しかも、本変形例では、上記実施の形態と比べて、回転楕円体の回転面の多くの部分を反射体４０Ａの反射面として利用している。具体的には、反射体４０Ａは、回転楕円体のうち２つの貫通孔４１ａ及び４１ｂと受光素子２０とを設けた箇所を除いた部分を反射面として利用している。 In addition, in this modification, as compared with the above embodiment, many portions of the rotation surface of the spheroid are used as the reflection surface of the reflector 40A. Specifically, the reflector 40A uses a portion of the spheroid excluding the portion where the two through holes 41a and 41b and the light receiving element 20 are provided as a reflecting surface.
　これにより、検知領域ＤＡにおける粒子の散乱光を多く取ることができるので、実施の形態１よりも高精度の粒子検出センサを実現できる。 Thereby, a large amount of scattered light of the particles in the detection area DA can be taken, so that a particle detection sensor with higher accuracy than that of the first embodiment can be realized.
　また、本変形例における粒子検出センサ１Ａでも、上記実施の形態１と同様に、反射体４０Ａは、楕円の一方の焦点が検知領域ＤＡ内に存在するように配置されており、また、受光素子２０は、楕円の他方の焦点の近傍に配置されている。 Also in the particle detection sensor 1A in the present modification, as in the first embodiment, the reflector 40A is arranged so that one focus of the ellipse exists in the detection area DA, and the light receiving element 20 is arranged in the vicinity of the other focus of the ellipse.
　これにより、検知領域ＤＡの粒子によって発生する散乱光を、少ない反射回数で受光素子２０に入射させることができるので、さらに高精度の粒子検出センサを実現できる。しかも、受光素子２０を楕円の焦点の近傍に配置することによって受光効率を高くできるので、受光素子２０として小型の光検出器等を用いることができる。 Thereby, since the scattered light generated by the particles in the detection area DA can be incident on the light receiving element 20 with a small number of reflections, a more accurate particle detection sensor can be realized. In addition, since the light receiving efficiency can be increased by arranging the light receiving element 20 in the vicinity of the focal point of the ellipse, a small photodetector or the like can be used as the light receiving element 20.
　なお、図１７では、２つの貫通孔４１ａ及び４１ｂは、当該貫通孔４１ａ及び４１ｂの中心軸が楕円の長軸と直交するように設けられているが、図１８に示される粒子検出センサ１Ａ’のように、反射体４０Ａ’の貫通孔４１ａ及び４１ｂの中心軸が楕円の長軸と傾斜して交差するように設けられていてもよい。 In FIG. 17, the two through holes 41a and 41b are provided so that the central axes of the through holes 41a and 41b are orthogonal to the major axis of the ellipse. However, the particle detection sensor 1A ′ shown in FIG. As described above, the central axes of the through holes 41a and 41b of the reflector 40A ′ may be provided so as to intersect with the long axis of the ellipse at an angle.
　（変形例２）
　図１９は、変形例２に係る粒子検出センサ１Ｂの概略構成を示す断面図である。 (Modification 2)
FIG. 19 is a cross-sectional view showing a schematic configuration of a particle detection sensor 1B according to Modification 2.
　図１９に示すように、本変形例における粒子検出センサ１Ｂは、上記実施の形態１における粒子検出センサ１と同様に、投光素子１０と投光レンズ３１ａと受光素子２０と反射体４０Ｂと加熱装置（不図示）とを備えており、検知領域ＤＡにおける粒子による投光素子１０の光の散乱光を受光素子２０で受光することにより気体中に含まれる粒子を検出する。 As shown in FIG. 19, the particle detection sensor 1B in the present modification is similar to the particle detection sensor 1 in the first embodiment described above, with the light projecting element 10, the light projecting lens 31a, the light receiving element 20, the reflector 40B, and the heating. And a device (not shown). The light receiving element 20 receives the scattered light of the light of the light projecting element 10 due to the particles in the detection area DA, thereby detecting particles contained in the gas.
　本変形例における反射体４０Ｂは、上記実施の形態１における反射体４０と同様に、内面が回転楕円体の回転面の一部をなしている。また、反射体４０Ｂは、楕円の一方の焦点が検知領域ＤＡ内に存在するように配置されており、受光素子２０は、楕円の他方の焦点の近傍に配置されている。 The reflector 40B in the present modification has an inner surface that forms part of the rotational surface of the spheroid, similar to the reflector 40 in the first embodiment. The reflector 40B is arranged so that one of the focal points of the ellipse exists in the detection area DA, and the light receiving element 20 is arranged in the vicinity of the other focal point of the ellipse.
　本変形例では、上記実施の形態１と異なり、投光素子１０の光軸と、受光素子２０の光軸と、反射体４０Ｂの回転軸（光軸）とが一致している。また、反射体４０Ｂにおいて、回転楕円体の長軸の端部には貫通孔４２が設けられている。投光素子１０から出射する光は、貫通孔４２を通過して検知領域ＤＡに投光される。 In the present modification, unlike the first embodiment, the optical axis of the light projecting element 10, the optical axis of the light receiving element 20, and the rotation axis (optical axis) of the reflector 40B are the same. In the reflector 40B, a through hole 42 is provided at the end of the major axis of the spheroid. The light emitted from the light projecting element 10 passes through the through hole 42 and is projected onto the detection area DA.
　さらに、本変形例では、投光素子１０と受光素子２０との間に遮蔽板６０が配置されている。遮蔽板６０は、投光素子１０から直接受光素子２０に入射する光を吸収又はカットするように構成された遮光板である。これにより、投光素子１０と受光素子２０との光軸が一致していても、投光素子１０の光のうち粒子に当たらずに受光素子２０に向かって直進する光が遮蔽板６０で遮蔽されるので、粒子の検出誤認を回避できる。 Furthermore, in this modification, a shielding plate 60 is disposed between the light projecting element 10 and the light receiving element 20. The shielding plate 60 is a shielding plate configured to absorb or cut light directly incident on the light receiving element 20 from the light projecting element 10. Thereby, even if the optical axes of the light projecting element 10 and the light receiving element 20 coincide with each other, the light that travels straight toward the light receiving element 20 without hitting the particles is blocked by the shielding plate 60. Therefore, erroneous detection of particles can be avoided.
　なお、本変形例でも、検知領域ＤＡが存在する粒子流路３３の流路方向は紙面垂直方向であり、粒子流路３３にはヒータ抵抗等の加熱装置が設置されている。 In this modification as well, the flow direction of the particle flow path 33 in which the detection area DA is present is the direction perpendicular to the paper surface, and the particle flow path 33 is provided with a heating device such as a heater resistor.
　以上、本変形例における粒子検出センサ１Ｂによれば、検知領域ＤＡにおける粒子の散乱光を反射して当該散乱光を受光素子２０に導く反射体４０Ｂを備えている。 As described above, the particle detection sensor 1B according to the present modification includes the reflector 40B that reflects the scattered light of the particles in the detection area DA and guides the scattered light to the light receiving element 20.
　これにより、加熱装置（不図示）を用いた加熱方式の粒子検出センサであっても、気体中に含まれる粒径の小さな粒子を高精度で検出することができる。 Thus, even a heating type particle detection sensor using a heating device (not shown) can detect particles with a small particle size contained in the gas with high accuracy.
　さらに、本変形例では、上記実施の形態１と比べて、回転楕円体の回転面の多くの部分を反射体４０Ｂの反射面として利用している。具体的には、反射体４０Ｂは、回転楕円体のうち１つの貫通孔４２と受光素子２０とを設けた箇所を除いた部分を反射面として利用している。 Furthermore, in this modification, as compared with the first embodiment, many portions of the rotation surface of the spheroid are used as the reflection surface of the reflector 40B. Specifically, the reflector 40B uses a portion of the spheroid excluding the portion where the one through hole 42 and the light receiving element 20 are provided as a reflecting surface.
　これにより、検知領域ＤＡにおける粒子の散乱光を多く取ることができるので、実施の形態１よりも高精度の粒子検出センサを実現できる。本変形例では、変形例１よりも回転楕円体の回転面を利用する部分が多く、反射面の面積が大きい。したがって、高感度の粒子検出センサを実現できる。 Thereby, a large amount of scattered light of the particles in the detection area DA can be taken, so that a particle detection sensor with higher accuracy than that of the first embodiment can be realized. In the present modification, there are more portions that use the rotation surface of the spheroid than Modification 1, and the area of the reflection surface is larger. Therefore, a highly sensitive particle detection sensor can be realized.
　また、本変形例における粒子検出センサ１Ｂでも、上記実施の形態１と同様に、反射体４０Ｂは、楕円の一方の焦点が検知領域ＤＡ内に存在するように配置されており、受光素子２０は、楕円の他方の焦点の近傍に配置されている。 Also in the particle detection sensor 1B according to the present modification, as in the first embodiment, the reflector 40B is arranged so that one focus of the ellipse exists in the detection area DA, and the light receiving element 20 is In the vicinity of the other focus of the ellipse.
　これにより、検知領域ＤＡの粒子によって発生する散乱光を、少ない反射回数で受光素子２０に入射させることができるので、さらに高感度の粒子検出センサを実現できる。しかも、受光素子２０を楕円の焦点の近傍に配置することによって受光効率を高くできるので、受光素子２０として小型の光検出器等を用いることができる。 Thereby, since the scattered light generated by the particles in the detection area DA can be incident on the light receiving element 20 with a small number of reflections, a more sensitive particle detection sensor can be realized. In addition, since the light receiving efficiency can be increased by arranging the light receiving element 20 in the vicinity of the focal point of the ellipse, a small photodetector or the like can be used as the light receiving element 20.
　（変形例３）
　図２０は、変形例３に係る粒子検出センサ１Ｃの概略構成を示す断面図である。 (Modification 3)
FIG. 20 is a cross-sectional view showing a schematic configuration of a particle detection sensor 1C according to Modification 3.
　図２０に示すように、本変形例における粒子検出センサ１Ｃは、上記実施の形態１における粒子検出センサ１と同様に、投光素子１０と投光レンズ３１ａと受光素子２０と反射体４０Ｃと加熱装置（不図示）とを備えており、検知領域ＤＡにおける粒子による投光素子１０の光の散乱光を受光素子２０で受光することにより気体中に含まれる粒子を検出する。 As shown in FIG. 20, the particle detection sensor 1C according to the present modification is similar to the particle detection sensor 1 according to the first embodiment described above, with the light projecting element 10, the light projecting lens 31a, the light receiving element 20, the reflector 40C, and the heating. And a device (not shown). The light receiving element 20 receives the scattered light of the light of the light projecting element 10 due to the particles in the detection area DA, thereby detecting particles contained in the gas.
　本変形例における反射体４０Ｃは、検知領域ＤＡにおける粒子による散乱光を反射して受光素子２０に導くものであるが、上記実施の形態１の反射体４０と異なり、回転楕円体の回転面ではなく、回転放物線の回転面の一部をなしている。 The reflector 40C in the present modification reflects scattered light caused by particles in the detection area DA and guides it to the light receiving element 20. However, unlike the reflector 40 of the first embodiment, the reflector 40C has a rotating surface of a spheroid. And part of the rotating surface of the parabola.
　本変形例において、反射体４０Ｃは、放物線の焦点Ｆが検知領域ＤＡ内に存在するように配置されており、受光素子２０は、放物線の焦点Ｆを挟んで放物線の頂点とは反対側の位置に配置されている。つまり、本変形例では、投光素子１０の光軸と、受光素子２０の光軸と、反射体４０Ｃの回転軸（光軸）とが一致している。 In this modification, the reflector 40C is arranged so that the parabolic focus F exists in the detection area DA, and the light receiving element 20 is positioned on the side opposite to the apex of the parabola across the parabolic focus F. Is arranged. That is, in the present modification, the optical axis of the light projecting element 10, the optical axis of the light receiving element 20, and the rotation axis (optical axis) of the reflector 40C are the same.
　反射体４０Ｃは、回転放物線の頂部に貫通孔４３が設けられている。投光素子１０から出射する光は、貫通孔４３を通過して反射体４０Ｃの内方部分に設定された検知領域ＤＡに投光される。 The reflector 40C is provided with a through-hole 43 at the top of the rotating parabola. The light emitted from the light projecting element 10 passes through the through hole 43 and is projected onto the detection area DA set in the inner part of the reflector 40C.
　さらに、本変形例では、投光素子１０と受光素子２０との間に遮蔽板６０が配置されている。これにより、投光素子１０と受光素子２０との光軸が一致していても、投光素子１０の光のうち粒子に当たらずに受光素子２０に直進する光が遮蔽板６０で遮蔽されるので、粒子の検出誤認を回避できる。 Furthermore, in this modification, a shielding plate 60 is disposed between the light projecting element 10 and the light receiving element 20. Thereby, even if the optical axes of the light projecting element 10 and the light receiving element 20 coincide with each other, the light that travels straight to the light receiving element 20 without hitting the particles is blocked by the shielding plate 60. Therefore, misdetection of particles can be avoided.
　なお、本変形例でも、検知領域ＤＡが存在する粒子流路３３の流路方向は紙面垂直方向であり、粒子流路３３にはヒータ抵抗等の加熱装置が設置されている。 In this modification as well, the flow direction of the particle flow path 33 in which the detection area DA is present is the direction perpendicular to the paper surface, and the particle flow path 33 is provided with a heating device such as a heater resistor.
　以上、本変形例における粒子検出センサ１Ｃによれば、検知領域ＤＡにおける粒子の散乱光を反射して当該散乱光を受光素子２０に導く反射体４０Ｃを備えている。 As described above, the particle detection sensor 1 </ b> C in the present modification includes the reflector 40 </ b> C that reflects the scattered light of the particles in the detection area DA and guides the scattered light to the light receiving element 20.
　これにより、加熱装置（不図示）を用いた加熱方式の粒子検出センサであっても、気体中に含まれる粒径の小さな粒子を高精度で検出することができる。 Thus, even a heating type particle detection sensor using a heating device (not shown) can detect particles with a small particle size contained in the gas with high accuracy.
　また、本変形例では、反射体４０Ｃの内面が回転放物線の回転面の一部をなしており、反射体４０は、放物線の焦点Ｆが検知領域ＤＡ内に存在するように配置されており、受光素子２０は、放物線の焦点Ｆを挟んで放物線の頂点とは反対側に位置するように配置されている。 Further, in this modification, the inner surface of the reflector 40C forms a part of the rotation surface of the rotating parabola, and the reflector 40 is arranged so that the focal point F of the parabola exists in the detection area DA, The light receiving element 20 is disposed so as to be located on the opposite side of the apex of the parabola across the parabolic focus F.
　この構成により、検知領域ＤＡに粒子が存在する場合、投光素子１０の光は検知領域ＤＡの粒子に当たって散乱し、当該散乱光は反射体４０Ｃで反射して平行光となって受光素子２０に入射する。これにより、検知領域ＤＡの粒子によって発生する散乱光を多く取ることができるとともに、当該散乱光を少ない反射回数で受光素子２０に入射させることができるので、高感度の粒子検出センサを実現できる。 With this configuration, when particles are present in the detection area DA, the light from the light projecting element 10 strikes and scatters the particles in the detection area DA, and the scattered light is reflected by the reflector 40C and becomes parallel light. Incident. Accordingly, a large amount of scattered light generated by the particles in the detection area DA can be obtained, and the scattered light can be incident on the light receiving element 20 with a small number of reflections, so that a highly sensitive particle detection sensor can be realized.
　これにより、検知領域ＤＡの粒子によって発生する散乱光を、少ない反射回数で受光素子２０に入射させることができるので、さらに高感度の粒子検出センサを実現できる。 Thereby, since the scattered light generated by the particles in the detection area DA can be incident on the light receiving element 20 with a small number of reflections, a more sensitive particle detection sensor can be realized.
　なお、本変形例では、反射体４０Ｃで反射した光が平行光となって広がるので、受光素子２０の受光面を大きくするか、受光素子２０の受光面を覆うレンズを大きくして、平行光の多くを受光素子２０で受光できるように構成するとよい。 In this modification, since the light reflected by the reflector 40C spreads as parallel light, the light receiving surface of the light receiving element 20 is enlarged or the lens that covers the light receiving surface of the light receiving element 20 is enlarged to produce parallel light. It is preferable that most of the light can be received by the light receiving element 20.
　（変形例４）
　図２１は、変形例４に係る粒子検出センサ１Ｄの概略構成を示す断面図である。 (Modification 4)
FIG. 21 is a cross-sectional view illustrating a schematic configuration of a particle detection sensor 1D according to Modification 4.
　図２１に示すように、本変形例における粒子検出センサ１Ｄは、変形例３における粒子検出センサ１Ｃと同様に、投光素子１０と投光レンズ３１ａと受光素子２０と反射体４０Ｄと加熱装置（不図示）とを備えており、検知領域ＤＡにおける粒子による投光素子１０の光の散乱光を受光素子２０で受光することにより気体中に含まれる粒子を検出する。 As shown in FIG. 21, the particle detection sensor 1D in the present modification example is similar to the particle detection sensor 1C in the modification example 3, and the light projecting element 10, the light projecting lens 31a, the light receiving element 20, the reflector 40D, and the heating device ( (Not shown), and the light receiving element 20 receives the scattered light of the light of the light projecting element 10 due to the particles in the detection area DA, thereby detecting particles contained in the gas.
　本変形例における反射体４０Ｄは、検知領域ＤＡにおける粒子による散乱光を反射して受光素子２０に導くものであり、変形例３と同様に、内面が回転放物線の回転面の一部をなしている。さらに、反射体４０Ｄの側部には、２つの貫通孔４４ａ及び４４ｂが設けられている。 The reflector 40D in the present modification reflects light scattered by particles in the detection area DA and guides it to the light receiving element 20, and the inner surface forms part of the rotation surface of the paraboloid as in the third modification. Yes. Further, two through holes 44a and 44b are provided on the side of the reflector 40D.
　また、投光素子１０及び投光レンズ３１ａは、貫通孔４４ａと対向するように配置されており、投光素子１０及び投光レンズ３１ａの光軸と２つの貫通孔４４ａ及び４４ｂの中心軸とが一致している。投光素子１０から出射する光は、貫通孔４４ａを通過して反射体４０Ｄの内方部分に設定された検知領域ＤＡに投光される。また、投光素子１０の光のうち粒子に当たらずに直進する光は、貫通孔４４ｂを通過して反射体４０Ｄの外部に抜けるので、受光素子２０に入射しない。 The light projecting element 10 and the light projecting lens 31a are arranged so as to face the through hole 44a, and the optical axis of the light projecting element 10 and the light projecting lens 31a and the central axes of the two through holes 44a and 44b are arranged. Match. The light emitted from the light projecting element 10 passes through the through hole 44a and is projected onto the detection area DA set in the inner part of the reflector 40D. Further, light that travels straight without hitting the particles out of the light from the light projecting element 10 passes through the through hole 44b and goes out of the reflector 40D, and therefore does not enter the light receiving element 20.
　本変形例でも、反射体４０Ｄは、放物線の焦点Ｆが検知領域ＤＡ内に存在するように配置されており、受光素子２０は、放物線の焦点Ｆを挟んで放物線の頂点とは反対側の位置に配置されている。 Also in the present modification, the reflector 40D is arranged so that the parabolic focus F exists in the detection area DA, and the light receiving element 20 is located on the opposite side of the parabola from the top of the parabola. Is arranged.
　なお、本変形例でも、検知領域ＤＡが存在する粒子流路３３の流路方向は紙面垂直方向であり、粒子流路３３にはヒータ抵抗等の加熱装置が設置されている。 In this modification as well, the flow direction of the particle flow path 33 in which the detection area DA is present is the direction perpendicular to the paper surface, and the particle flow path 33 is provided with a heating device such as a heater resistor.
　以上、本変形例における粒子検出センサ１Ｄによれば、検知領域ＤＡにおける粒子の散乱光を反射して当該散乱光を受光素子２０に導く反射体４０Ｄを備えている。 As described above, the particle detection sensor 1D according to the present modification includes the reflector 40D that reflects the scattered light of the particles in the detection area DA and guides the scattered light to the light receiving element 20.
　これにより、加熱装置（不図示）を用いた加熱方式の粒子検出センサであっても、気体中に含まれる粒径の小さな粒子を高精度で検出することができる。 Thus, even a heating type particle detection sensor using a heating device (not shown) can detect particles with a small particle size contained in the gas with high accuracy.
　また、本変形例では、変形例３と同様に、回転放物線の回転面からなる反射体４０Ｄは、放物線の焦点Ｆが検知領域ＤＡ内に存在するように配置されており、受光素子２０は、放物線の焦点Ｆを挟んで放物線の頂点とは反対側に位置するように配置されている。 Further, in the present modification, as in the modification 3, the reflector 40D formed of the rotation surface of the rotating parabola is arranged so that the focal point F of the parabola exists in the detection area DA, and the light receiving element 20 is It is arranged so as to be located on the side opposite to the apex of the parabola across the focal point F of the parabola.
　これにより、変形例３と同様に、検知領域ＤＡにおける粒子の散乱光は反射体４０Ｄで反射して平行光となって受光素子２０に入射するので、検知領域ＤＡの粒子によって発生する散乱光を多く取ることができるとともに、当該散乱光を少ない反射回数で受光素子２０に入射させることができる。したがって、高感度の粒子検出センサを実現できる。 As a result, similarly to the third modification, the scattered light of the particles in the detection area DA is reflected by the reflector 40D and becomes parallel light and enters the light receiving element 20, so that the scattered light generated by the particles in the detection area DA is reduced. A large amount can be obtained, and the scattered light can be incident on the light receiving element 20 with a small number of reflections. Therefore, a highly sensitive particle detection sensor can be realized.
　なお、本変形例でも、反射体４０Ｄで反射した光が平行光となって広がるので、受光素子２０の受光面を大きくするか、受光素子２０の受光面を覆うレンズを大きくして、平行光の多くを受光素子２０で受光できるように構成するとよい。あるいは、図２２に示される粒子検出センサ１Ｄ’のように、受光素子２０の手前に集光レンズ７０を配置してもよい。 In this modification as well, since the light reflected by the reflector 40D spreads as parallel light, the light receiving surface of the light receiving element 20 is increased or the lens covering the light receiving surface of the light receiving element 20 is increased to generate parallel light. It is preferable that most of the light can be received by the light receiving element 20. Or you may arrange | position the condensing lens 70 in front of the light receiving element 20 like particle | grain detection sensor 1D 'shown by FIG.
　（変形例５）
　図２３は、変形例５に係る粒子検出センサ１Ｅの概略構成を示す断面図である。 (Modification 5)
FIG. 23 is a cross-sectional view illustrating a schematic configuration of a particle detection sensor 1E according to Modification 5.
　図２３に示すように、本変形例における粒子検出センサ１Ｅは、上記実施の形態１における粒子検出センサ１と同様に、投光素子１０と受光素子２０と反射体４０と加熱装置（不図示）とを備えており、検知領域ＤＡにおける粒子による投光素子１０の光の散乱光を受光素子２０で受光することにより気体中に含まれる粒子を検出する。 As shown in FIG. 23, the particle detection sensor 1E in the present modification is similar to the particle detection sensor 1 in the first embodiment, in which the light projecting element 10, the light receiving element 20, the reflector 40, and a heating device (not shown). The light receiving element 20 receives the scattered light of the light of the light projecting element 10 due to the particles in the detection area DA, thereby detecting the particles contained in the gas.
　本変形例でも、上記実施の形態１と同様に、回転楕円体の回転面からなる反射体４０は、楕円の一方の焦点が検知領域ＤＡ内に存在するように配置されており、また、受光素子２０は、楕円の他方の焦点の近傍に配置されている。 Also in the present modification, as in the first embodiment, the reflector 40 formed of the rotation surface of the spheroid is arranged so that one focal point of the ellipse exists in the detection area DA, and also receives light. The element 20 is disposed in the vicinity of the other focus of the ellipse.
　そして、本変形例における粒子検出センサ１Ｅは、さらに、補助反射体４０Ｅを備える。補助反射体４０Ｅは、検知領域ＤＡにおける粒子による散乱光のうち反射体４０に向かわない散乱光を反射体４０に向けて反射する。補助反射体４０Ｅは、例えば、所定形状の凹曲面を有する反射ミラーである。 And the particle | grain detection sensor 1E in this modification is further provided with the auxiliary reflector 40E. The auxiliary reflector 40E reflects the scattered light that does not go to the reflector 40 out of the scattered light from the particles in the detection area DA toward the reflector 40. The auxiliary reflector 40E is, for example, a reflection mirror having a concave curved surface with a predetermined shape.
　なお、本変形例でも、検知領域ＤＡが存在する粒子流路３３の流路方向は紙面垂直方向であり、粒子流路３３にはヒータ抵抗等の加熱装置が設置されている。 In this modification as well, the flow direction of the particle flow path 33 in which the detection area DA is present is the direction perpendicular to the paper surface, and the particle flow path 33 is provided with a heating device such as a heater resistor.
　以上、本変形例における粒子検出センサ１Ｅによれば、上記実施の形態１と同様に、検知領域ＤＡにおける粒子の散乱光を反射して当該散乱光を受光素子２０に導く反射体４０を備えている。 As described above, the particle detection sensor 1E according to the present modification includes the reflector 40 that reflects the scattered light of the particles in the detection area DA and guides the scattered light to the light receiving element 20 as in the first embodiment. Yes.
　これにより、加熱装置（不図示）を用いた加熱方式の粒子検出センサであっても、気体中に含まれる粒径の小さな粒子を高精度で検出することができる。 Thus, even a heating type particle detection sensor using a heating device (not shown) can detect particles with a small particle size contained in the gas with high accuracy.
　さらに、本変形例では、補助反射体４０Ｅを備えているので、検知領域ＤＡにおける粒子による散乱光のうち反射体４０に向かわない散乱光を反射体４０に向けて反射させることができる。 Furthermore, in this modification, since the auxiliary reflector 40E is provided, the scattered light that does not go to the reflector 40 among the scattered light from the particles in the detection area DA can be reflected toward the reflector 40.
　これにより、検知領域ＤＡにおける粒子の散乱光を多く取ることができるので、高感度の粒子検出センサを実現できる。 As a result, a large amount of scattered light from the particles in the detection area DA can be obtained, so that a highly sensitive particle detection sensor can be realized.
　また、本変形例における粒子検出センサ１Ｅでは、上記実施の形態１と同様に、反射体４０は、楕円の一方の焦点が検知領域ＤＡ内に存在するように配置されており、受光素子２０は、楕円の他方の焦点の近傍に配置されている。 Further, in the particle detection sensor 1E in the present modification, as in the first embodiment, the reflector 40 is arranged so that one focus of the ellipse exists in the detection area DA, and the light receiving element 20 is In the vicinity of the other focus of the ellipse.
　これにより、検知領域ＤＡの粒子によって発生する散乱光を、少ない反射回数で受光素子２０に入射させることができるので、さらに高感度の粒子検出センサを実現できる。しかも、受光素子２０を楕円の焦点の近傍に配置することによって受光効率を高くできるので、受光素子２０として小型の光検出器等を用いることができる。 Thereby, since the scattered light generated by the particles in the detection area DA can be incident on the light receiving element 20 with a small number of reflections, a more sensitive particle detection sensor can be realized. In addition, since the light receiving efficiency can be increased by arranging the light receiving element 20 in the vicinity of the focal point of the ellipse, a small photodetector or the like can be used as the light receiving element 20.
　（変形例６）
　図２４は、変形例６に係る粒子検出センサ１Ｆの概略構成を示す断面図である。 (Modification 6)
FIG. 24 is a cross-sectional view illustrating a schematic configuration of a particle detection sensor 1F according to Modification 6.
　図２４に示すように、本変形例における粒子検出センサ１Ｆは、上記実施の形態１における粒子検出センサ１と同様に、投光素子１０と受光素子２０と反射体４０Ｆと加熱装置（不図示）とを備えており、検知領域ＤＡにおける粒子による投光素子１０の光の散乱光を受光素子２０で受光することにより気体中に含まれる粒子を検出する。本変形例でも、検知領域ＤＡが存在する粒子流路（不図示）の流路方向は、紙面垂直方向である。 As shown in FIG. 24, the particle detection sensor 1F according to the present modification is similar to the particle detection sensor 1 according to the first embodiment, and includes a light projecting element 10, a light receiving element 20, a reflector 40F, and a heating device (not shown). The light receiving element 20 receives the scattered light of the light of the light projecting element 10 due to the particles in the detection area DA, thereby detecting the particles contained in the gas. Also in this modification, the flow channel direction of the particle flow channel (not shown) in which the detection area DA exists is the direction perpendicular to the paper surface.
　本変形例における反射体４０Ｆは、知領域ＤＡにおける粒子による散乱光を反射して受光素子２０に導くものであり、各々が曲面又は平面を有する複数の微小ミラーの集合体である。反射体４０Ｆの内面は、全体として略回転放物線の回転面の一部をなすような形状である。つまり、上記実施の形態１のように連続する滑らかな曲面からなる反射体ではなく、各々の内面が曲面状又は平面状の複数の微小ミラーによって構成された反射体４０Ｆを用いてもよい。 The reflector 40F in the present modification reflects light scattered by particles in the knowledge area DA and guides it to the light receiving element 20, and is an assembly of a plurality of micromirrors each having a curved surface or a flat surface. The inner surface of the reflector 40F has a shape that forms a part of the rotation surface of a substantially parabolic paraboloid as a whole. That is, instead of a reflector having a smooth curved surface as in the first embodiment, a reflector 40F in which each inner surface is configured by a plurality of minute mirrors having a curved surface or a flat surface may be used.
　なお、本変形例でも、検知領域ＤＡが存在する粒子流路３３の流路方向は紙面垂直方向であり、粒子流路３３にはヒータ抵抗等の加熱装置が設置されている。 In this modification as well, the flow direction of the particle flow path 33 in which the detection area DA is present is the direction perpendicular to the paper surface, and the particle flow path 33 is provided with a heating device such as a heater resistor.
　以上、本変形例における粒子検出センサ１Ｆによれば、上記実施の形態１と同様に、検知領域ＤＡにおける粒子の散乱光を反射して当該散乱光を受光素子２０に導く反射体４０Ｆを備えている。 As described above, according to the particle detection sensor 1F in the present modification, the reflector 40F that reflects the scattered light of the particles in the detection area DA and guides the scattered light to the light receiving element 20 is provided as in the first embodiment. Yes.
　これにより、加熱装置（不図示）を用いた加熱方式の粒子検出センサであっても、気体中に含まれる粒径の小さな粒子を高精度で検出することができる。 Thus, even a heating type particle detection sensor using a heating device (not shown) can detect particles with a small particle size contained in the gas with high accuracy.
　また、本変形例でも、反射体４０Ｆの内面が略回転楕円体の回転面の一部をなしており、反射体４０Ｆは、楕円の一方の焦点が検知領域ＤＡ内に存在するように配置されており、受光素子２０は、楕円の他方の焦点の近傍に配置されている。 Also in this modified example, the inner surface of the reflector 40F forms a part of the rotation surface of the substantially spheroid, and the reflector 40F is arranged so that one focus of the ellipse exists in the detection area DA. The light receiving element 20 is disposed in the vicinity of the other focal point of the ellipse.
　これにより、検知領域ＤＡの粒子によって発生する散乱光を、少ない反射回数で受光素子２０に入射させることができるので、高感度の粒子検出センサを実現できる。しかも、受光素子２０を楕円の焦点の近傍に配置することによって受光効率を高くできるので、受光素子２０として小型の光検出器等を用いることができる。 Thereby, since the scattered light generated by the particles in the detection area DA can be incident on the light receiving element 20 with a small number of reflections, a highly sensitive particle detection sensor can be realized. In addition, since the light receiving efficiency can be increased by arranging the light receiving element 20 in the vicinity of the focal point of the ellipse, a small photodetector or the like can be used as the light receiving element 20.
　（その他変形例等）
　以上、本発明に係る粒子検出センサについて、実施の形態及び変形例に基づいて説明したが、本発明は、上記の実施の形態及び変形例に限定されるものではない。 (Other variations)
As mentioned above, although the particle | grain detection sensor which concerns on this invention was demonstrated based on embodiment and a modification, this invention is not limited to said embodiment and a modification.
　例えば、上記実施の形態１～３において、粒子流路３３の流路方向（測定対象の気体が流れる方向）は、紙面上下方向（鉛直方向）としているが、紙面垂直方向としてもよい。つまり、上記実施の形態１～３では、粒子流路３３の流路軸は、投光素子１０及び受光素子２０の各光軸が通る平面上に存在するように設定したが、当該平面と直交するように設定してもよい。 For example, in the first to third embodiments, the flow direction of the particle flow channel 33 (the direction in which the gas to be measured flows) is the vertical direction (vertical direction) on the paper surface, but may be the vertical direction on the paper surface. That is, in the first to third embodiments, the flow path axis of the particle flow path 33 is set to exist on a plane through which each optical axis of the light projecting element 10 and the light receiving element 20 passes, but is orthogonal to the plane. You may set to do.
　また、上記実施の形態１～３において、大気導入孔３５及び大気排出孔３６は、鉛直方向における筐体３０の上面及び底面に設けたが、これに限るものではない。図２５に示す粒子検出センサ１Ｇのように、筐体３０（図２５では第１筐体部３０ａ）の主面に大気導入孔３５及び大気排出孔３６を設けてもよい。 In the first to third embodiments, the air introduction hole 35 and the air discharge hole 36 are provided on the upper surface and the bottom surface of the casing 30 in the vertical direction. However, the present invention is not limited to this. Like the particle detection sensor 1G shown in FIG. 25, the air introduction hole 35 and the air discharge hole 36 may be provided on the main surface of the housing 30 (the first housing portion 30a in FIG. 25).
　この場合、図２５に示すように、遮光体６３を設けてもよい。遮光体６３は、第１遮光体６１及び第２遮光体６２と同様に、加熱装置５０からの光及び外光の少なくとも一方を遮光するものであり、かつ、検知領域ＤＡにおける粒子の散乱光が当該遮光体６３に到達した場合に、当該散乱光が検知領域ＤＡに反射することを抑制する形状となっている。なお、遮光体６３には、第１遮光体６１及び第２遮光体６２の構成を適宜適用することができる。 In this case, a light shield 63 may be provided as shown in FIG. Similar to the first light shielding body 61 and the second light shielding body 62, the light shielding body 63 shields at least one of the light from the heating device 50 and the outside light, and the scattered light of the particles in the detection area DA When the light reaches the light shield 63, the scattered light is prevented from being reflected on the detection area DA. In addition, the structure of the 1st light shielding body 61 and the 2nd light shielding body 62 can be applied to the light shielding body 63 suitably.
　また、上記実施の形態１～３において、反射体の内面は、回転楕円体又は回転放物線の表面の一部としたが、これに限るものではなく、円錐曲線の回転体の回転面の一部とすることができる。この場合、円錐曲線としては、円ではなく、楕円、放物線及び双曲線の中から選ぶとよい。つまり、反射体の内面は、球体の曲面（球面）よりも、回転楕円体や回転放物線、回転双曲線の曲面（回転面）の一部にするとよい。反射体の内面が球面である場合、積分球のように拡散反射を利用すると、散乱光が何回も反射（多重反射）して減衰して、受光素子２０に光があまり入らなくなる。例えば、回転楕円体の場合と比べて、球体の場合は、１／１００程度しか受光しなくなる。 In the first to third embodiments, the inner surface of the reflector is a part of the surface of the spheroid or parabola, but the present invention is not limited to this. It can be. In this case, the conic curve may be selected from an ellipse, a parabola and a hyperbola instead of a circle. That is, the inner surface of the reflector is preferably a part of a spheroid, rotating parabola, or rotating hyperbolic curved surface (rotating surface) rather than a spherical curved surface (spherical surface). When the inner surface of the reflector is spherical, if diffuse reflection is used like an integrating sphere, scattered light is reflected (multiple reflection) and attenuated many times, so that light does not enter the light receiving element 20 so much. For example, in the case of a sphere, only about 1/100 is received compared to the case of a spheroid.
　また、上記実施の形態１～３において、受光領域３２には反射体を配置したが、受光領域３２には、反射体に代えてレンズを配置してもよい。例えば、受光領域３２に、検知領域ＤＡにおける粒子の散乱光を受光素子２０に集光させる集光レンズを配置してもよい。 In the first to third embodiments, a reflector is disposed in the light receiving region 32. However, a lens may be disposed in the light receiving region 32 instead of the reflector. For example, a condensing lens that collects the scattered light of particles in the detection area DA on the light receiving element 20 may be disposed in the light receiving area 32.
　また、上記実施の形態２において、第１遮光体６１は、ヒータ光及び外光の両方を遮光するとしたが、いずれか一方のみを遮光するように構成してもよい。この場合、第１遮光体６１がヒータ光のみを遮蔽するヒータ光遮蔽体である場合、さらに、大気導入孔３５からの外光を遮蔽する入口外光遮蔽体を別途設けてもよい。あるいは、第１遮光体６１が大気導入孔３５からの外光のみを遮蔽する入口外光遮蔽体である場合、さらに、ヒータ光を遮蔽するヒータ光遮蔽体を別途設けてもよい。 In the second embodiment, the first light shield 61 is configured to shield both the heater light and the outside light, but may be configured to shield only one of them. In this case, when the first light shield 61 is a heater light shield that shields only the heater light, an entrance external light shield that shields the external light from the air introduction hole 35 may be additionally provided. Alternatively, when the first light shield 61 is an entrance external light shield that shields only the external light from the air introduction hole 35, a heater light shield that shields the heater light may be additionally provided.
　また、上記実施の形態３において、清掃具導入孔３７は、大気導入孔３５及び大気排出孔３６とは別に設けられていた（つまり、清掃具導入孔３７は清掃専用の孔であった）が、大気導入孔３５及び大気排出孔３６を清掃具導入孔として用いてもよい。この場合、清掃具を大気導入孔３５及び大気排出孔３６から挿入して第１保護板９１や第２保護板９２の表面の付着物を取り除いてもよい。 In the third embodiment, the cleaning tool introduction hole 37 is provided separately from the air introduction hole 35 and the air discharge hole 36 (that is, the cleaning tool introduction hole 37 is a hole dedicated for cleaning). The air introduction hole 35 and the air discharge hole 36 may be used as the cleaning tool introduction hole. In this case, a cleaning tool may be inserted from the air introduction hole 35 and the air discharge hole 36 to remove the deposits on the surfaces of the first protection plate 91 and the second protection plate 92.
　また、上記実施の形態１～３における粒子検出センサは、様々な機器に利用することができる。例えば、粒子検出センサをダストセンサに搭載することで、粒子検出センサを備えるダストセンサとして実現することができる。この場合、ダストセンサは、内蔵する粒子検出センサによってホコリの粒子を検知した場合、ホコリを検知したことを音や光によって報知したり表示部に表示したりする。 In addition, the particle detection sensor in the first to third embodiments can be used for various devices. For example, by mounting the particle detection sensor on the dust sensor, it can be realized as a dust sensor including the particle detection sensor. In this case, when the dust sensor detects dust particles with the built-in particle detection sensor, the dust sensor notifies the detection of dust by sound or light or displays the dust on the display unit.
　また、上記実施の形態１～３における粒子検出センサは、当該粒子検出センサを煙感知器に搭載することで、図２６に示すような煙感知器として実現することもできる。この場合、煙感知器は、内蔵する粒子検出センサによって煙の粒子を検知した場合、煙を検知したことを音や光によって報知したり表示部に表示したりする。 In addition, the particle detection sensor in the first to third embodiments can be realized as a smoke detector as shown in FIG. 26 by mounting the particle detection sensor on the smoke detector. In this case, when the smoke detector detects smoke particles with the built-in particle detection sensor, the smoke detector notifies the detection of smoke by sound or light or displays the smoke on the display unit.
　また、上記実施の形態１～３における粒子検出センサ又は上記ダストセンサは、空気清浄機、換気扇又はエアコンに搭載することで、図２７に示すような空気清浄機、図２８に示すような換気扇又は図２９に示すようなエアコンとして実現することができる。この場合、空気清浄機、換気扇又はエアコンは、内蔵する粒子検出センサによってホコリの粒子を検知した場合、単にホコリを検知したことを表示部に表示してもよいし、ファンを起動したりファンの回転速度を変更したり等のファンの制御を行ったりしてもよい。 Further, the particle detection sensor or the dust sensor in the first to third embodiments is mounted on an air purifier, a ventilation fan, or an air conditioner, so that an air purifier as shown in FIG. 27, a ventilation fan as shown in FIG. It can be realized as an air conditioner as shown in FIG. In this case, the air purifier, the ventilation fan, or the air conditioner may detect that dust is detected by the built-in particle detection sensor, and may simply display that the dust is detected on the display unit or activate the fan. The fan may be controlled such as changing the rotation speed.
　また、これらの機器において、実施の形態３の変形例４のように清掃具導入孔３７を備える粒子検出センサ３Ｄを用いる場合、粒子検出センサ３Ｄは機器の外郭筐体に内蔵されることになるが、ユーザが綿棒等の清掃具２００を筐体３０内に挿入して第１保護板９１や第２保護板９２を容易に清掃できるように、機器の外郭筐体における清掃具導入孔３７に対向する部分には貫通孔が設けられていてもよい。これにより、当該貫通孔から清掃具導入孔３７に向かって清掃具２００を挿入できるので、第１保護板９１及び第２保護板９２の清掃を容易に行うことができる。 Further, in these devices, when the particle detection sensor 3D including the cleaning tool introduction hole 37 is used as in the fourth modification of the third embodiment, the particle detection sensor 3D is built in the outer casing of the device. However, the user can insert the cleaning tool 200 such as a cotton swab into the housing 30 and easily clean the first protective plate 91 and the second protective plate 92 in the cleaning tool introduction hole 37 in the outer casing of the device. A through hole may be provided in the facing portion. Thereby, since the cleaning tool 200 can be inserted toward the cleaning tool introduction hole 37 from the said through-hole, the 1st protection board 91 and the 2nd protection board 92 can be cleaned easily.
　なお、上記の各実施の形態及び変形例おいて、粒子を含む媒体は、大気（空気）としたが、本発明は、大気以外の媒体（水等の液体）にも適用することができる。 In each of the above embodiments and modifications, the medium containing particles is the atmosphere (air), but the present invention can also be applied to a medium other than the atmosphere (liquid such as water).
　その他、各実施の形態及び変形例に対して当業者が思いつく各種変形を施して得られる形態や、本発明の趣旨を逸脱しない範囲で各実施の形態及び変形例における構成要素及び機能を任意に組み合わせることで実現される形態も本発明に含まれる。 In addition, the form obtained by making various modifications conceived by those skilled in the art with respect to each embodiment and modification, and the components and functions in each embodiment and modification are arbitrarily set within the scope of the present invention. Forms realized by combining them are also included in the present invention.
　１、１Ａ、１Ａ’、１Ｂ、１Ｃ、１Ｄ、１Ｄ’、１Ｅ、１Ｆ、１Ｇ、２、３、３Ａ、３Ｂ、３Ｃ、３Ｄ　粒子検出センサ
　１０　投光素子
　１１、２１、５１　リード線
　２０　受光素子
　３０　筐体
　３０ａ　第１筐体部
　３０ｂ　第２筐体部
　３１　投光領域
　３２　受光領域
　３３　粒子流路
　３４　トラップ部
　３４ａ　投光トラップ部
　３４ｂ　受光トラップ部
　３５　大気導入孔
　３６　大気排出孔
　３７　清掃具導入孔
　３８　蓋
　４０、４０Ａ、４０Ｂ、４０Ｃ、４０Ｄ、４０Ｆ　反射体
　４０Ｅ　補助反射体
　４１ａ、４１ｂ、４２、４３、４４ａ、４４ｂ　貫通孔
　５０　加熱装置
　６０　遮蔽板
　６１　第１遮光体（遮光体）
　６１ａ　第１遮光壁
　６１ｂ　第２遮光壁
　６２　第２遮光体（遮光体）
　６２ａ　第１遮光壁
　６２ｂ　第２遮光壁
　６２ｃ　第３遮光壁
　６３　遮光体
　７０　集光レンズ
　７１　投光絞り部
　７２　投光反対絞り部
　７３　受光反対絞り部
　８１　第１保護板
　８２　第２保護板
　９１　第１保護板
　９２　第２保護板
　２００　清掃具 1, 1A, 1A ′, 1B, 1C, 1D, 1D ′, 1E, 1F, 1G, 2, 3, 3A, 3B, 3C, 3D Particle detection sensor 10 Light emitting element 11, 21, 51 Lead wire 20 Light receiving element 30 casing 30a first casing section 30b second casing section 31 light projecting area 32 light receiving area 33 particle flow path 34 trap section 34a light projecting trap section 34b light receiving trap section 35 atmosphere introduction hole 36 atmosphere discharge hole 37 cleaning tool introduction Hole 38 Lid 40, 40A, 40B, 40C, 40D, 40F Reflector 40E Auxiliary reflector 41a, 41b, 42, 43, 44a, 44b Through hole 50 Heating device 60 Shield plate 61 First light shield (light shield)
61a First light shielding wall 61b Second light shielding wall 62 Second light shielding body (light shielding body)
62a 1st light shielding wall 62b 2nd light shielding wall 62c 3rd light shielding wall 63 Light-shielding body 70 Condensing lens 71 Light projection diaphragm part 72 Light projection opposite diaphragm part 73 Light reception opposite diaphragm part 81 1st protection board 82 2nd protection board 91 1st 1 protection plate 92 2nd protection plate 200 cleaning tool

Claims (32)

  1. 　投光素子と受光素子とを備え、検知領域における粒子による前記投光素子の光の散乱光を前記受光素子で受光することにより気体中に含まれる粒子を検出する粒子検出センサであって、
    　気体を加熱する加熱装置と、
    　前記散乱光を反射して当該散乱光を前記受光素子に導く反射体とを有する
    　粒子検出センサ。     A particle detection sensor comprising a light projecting element and a light receiving element, and detecting particles contained in a gas by receiving scattered light of the light of the light projecting element due to particles in a detection region by the light receiving element,
    A heating device for heating the gas;
    A particle detection sensor comprising: a reflector that reflects the scattered light and guides the scattered light to the light receiving element.
  2. 　前記反射体は、前記散乱光を前記受光素子に集光させる
    　請求項１に記載の粒子検出センサ。     The particle detection sensor according to claim 1, wherein the reflector focuses the scattered light on the light receiving element.
  3. 　前記反射体は、前記散乱光を前記受光素子に向けて反射する
    　請求項１又は２に記載の粒子検出センサ。     The particle detection sensor according to claim 1, wherein the reflector reflects the scattered light toward the light receiving element.
  4. 　前記反射体の内面は、曲面である
    　請求項１～３のいずれか１項に記載の粒子検出センサ。     The particle detection sensor according to any one of claims 1 to 3, wherein an inner surface of the reflector is a curved surface.
  5. 　前記反射体の内面は、楕円の回転体の回転面の一部であり、
    　前記反射体は、前記楕円における一方の焦点が前記検知領域内に存在するように配置されており、
    　前記受光素子は、前記楕円における他方の焦点近傍に配置される
    　請求項１～３のいずれか１項に記載の粒子検出センサ。     The inner surface of the reflector is a part of the rotating surface of the elliptical rotating body,
    The reflector is arranged so that one focal point of the ellipse exists in the detection area;
    The particle detection sensor according to any one of claims 1 to 3, wherein the light receiving element is disposed in the vicinity of the other focal point of the ellipse.
  6. 　さらに、前記投光素子の前方に配置された投光レンズを有し、
    　前記投光レンズから出射する光の集光点は、前記楕円の前記一方の焦点と一致している
    　請求項５に記載の粒子検出センサ。     And a light projecting lens disposed in front of the light projecting element,
    The particle detection sensor according to claim 5, wherein a condensing point of light emitted from the light projecting lens coincides with the one focal point of the ellipse.
  7. 　前記反射体の内面は、放物線の回転体の回転面の一部であり、
    　前記反射体は、前記放物線の焦点が前記検知領域内に存在するように配置されており、
    　前記受光素子は、前記放物線の焦点を挟んで前記放物線の頂点とは反対側の位置に配置される
    　請求項１～３のいずれか１項に記載の粒子検出センサ。     The inner surface of the reflector is a part of the rotation surface of the parabolic rotator,
    The reflector is arranged such that the focus of the parabola is in the detection area;
    The particle detection sensor according to any one of claims 1 to 3, wherein the light receiving element is disposed at a position opposite to an apex of the parabola with a focus of the parabola.
  8. 　前記反射体は、前記散乱光を前記受光素子に導くための空間領域である受光領域に配置されている
    　請求項１～７のいずれか１項に記載の粒子検出センサ。     The particle detection sensor according to any one of claims 1 to 7, wherein the reflector is disposed in a light receiving region that is a spatial region for guiding the scattered light to the light receiving element.
  9. 　前記検知領域を含む空間領域であって粒子を含む気体が流れる空間領域である粒子流路を有し、
    　前記受光領域は、前記粒子流路に向かって開口する開口部を有し、
    　前記反射体は、前記粒子流路に向かって開口する開口部を有し、
    　前記受光領域の前記開口部と前記反射体の前記開口部とは略一致する
    　請求項８に記載の粒子検出センサ。     A particle region that is a space region including the detection region and a space region through which a gas including particles flows,
    The light receiving region has an opening that opens toward the particle flow path,
    The reflector has an opening that opens toward the particle channel,
    The particle detection sensor according to claim 8, wherein the opening of the light receiving region and the opening of the reflector substantially coincide with each other.
  10. 　さらに、前記投光素子の光が投光される空間領域である投光領域に設けられた投光絞り部を有する
    　請求項１～９のいずれか１項に記載の粒子検出センサ。     The particle detection sensor according to any one of claims 1 to 9, further comprising a light projection stop portion provided in a light projection region that is a space region where light from the light projecting element is projected.
  11. 　前記投光絞り部は、開口を有する光学絞りであり、
    　前記光学絞りの開口の端部は、当該光学絞りの光軸を含む断面において２つの直線によって鋭角をなし、
    　前記２つの直線の一方を含む面は、入射する光を前記検知領域以外の方向に反射させる反射面である
    　請求項１０に記載の粒子検出センサ。     The projection diaphragm is an optical diaphragm having an opening,
    The end of the aperture of the optical diaphragm forms an acute angle by two straight lines in a cross section including the optical axis of the optical diaphragm,
    The particle detection sensor according to claim 10, wherein the surface including one of the two straight lines is a reflection surface that reflects incident light in a direction other than the detection region.
  12. 　前記投光絞り部は、各々が開口を有する複数の光学絞りからなり、
    　当該複数の光学絞りの各々の開口の先端を結ぶ仮想線と、前記投光素子から出射して前記検知領域に向かう光の輪郭線とが略平行である
    　請求項１０又は１１に記載の粒子検出センサ。     The projection diaphragm unit is composed of a plurality of optical diaphragms each having an opening,
    12. The particle detection according to claim 10, wherein an imaginary line connecting tips of openings of the plurality of optical diaphragms and a contour line of light emitted from the light projecting element and directed to the detection region are substantially parallel. Sensor.
  13. 　さらに、前記検知領域を挟んで前記投光素子の反対側に設けられた投光反対絞り部を有する
    　請求項１～１２のいずれか１項に記載の粒子検出センサ。     The particle detection sensor according to any one of claims 1 to 12, further comprising a light projection opposite stop provided on the opposite side of the light projecting element with the detection region interposed therebetween.
  14. 　前記投光反対絞り部は、開口を有する光学絞りであり、
    　前記光学絞りの開口の端部は、当該光学絞りの光軸を含む断面において２つの直線によって鋭角をなし、
    　前記２つの直線の一方を含む面は、入射する光を前記検知領域以外の方向に反射させる反射面である
    　請求項１３に記載の粒子検出センサ。     The light projection opposite stop portion is an optical stop having an opening,
    The end of the aperture of the optical diaphragm forms an acute angle by two straight lines in a cross section including the optical axis of the optical diaphragm,
    The particle detection sensor according to claim 13, wherein the surface including one of the two straight lines is a reflection surface that reflects incident light in a direction other than the detection region.
  15. 　前記投光反対絞り部は、各々が開口を有する複数の光学絞りからなり、
    　当該複数の光学絞りの各々の開口の先端を結ぶ仮想線と、前記投光素子から出射して前記検知領域を通過する光の輪郭線とが略平行である
    　請求項１３又は１４に記載の粒子検出センサ。     The light projection opposite stop portion comprises a plurality of optical stops each having an opening,
    The particle according to claim 13 or 14, wherein an imaginary line connecting tips of openings of each of the plurality of optical diaphragms and a contour line of light emitted from the light projecting element and passing through the detection region are substantially parallel. Detection sensor.
  16. 　さらに、前記検知領域を通過した前記投光素子の光を吸収する投光トラップ部を有し、
    　前記投光反対絞り部は、前記投光トラップ部に設けられている
    　請求項１３～１５のいずれか１項に記載の粒子検出センサ。     Furthermore, it has a light projecting trap part that absorbs light of the light projecting element that has passed through the detection region,
    The particle detection sensor according to any one of claims 13 to 15, wherein the light projection counter diaphragm portion is provided in the light projection trap portion.
  17. 　さらに、前記検知領域を挟んで前記受光素子の反対側に設けられた受光反対絞り部を有する
    　請求項１～１６のいずれか１項に記載の粒子検出センサ。     The particle detection sensor according to any one of claims 1 to 16, further comprising a light reception counter diaphragm provided on an opposite side of the light receiving element with the detection region interposed therebetween.
  18. 　さらに、前記受光素子とは反対側に進行する光を吸収する受光トラップ部を有し、
    　前記受光反対絞り部は、前記受光トラップ部に設けられている
    　請求項１７に記載の粒子検出センサ。     Furthermore, it has a light receiving trap part that absorbs light traveling on the opposite side of the light receiving element,
    The particle detection sensor according to claim 17, wherein the light receiving counter diaphragm portion is provided in the light receiving trap portion.
  19. 　前記投光素子から出射して前記検知領域に向かう光の輪郭線と前記反射体の端面を結ぶ仮想線とが略平行である
    　請求項１～１８のいずれか１項に記載の粒子検出センサ。     The particle detection sensor according to any one of claims 1 to 18, wherein a contour line of light emitted from the light projecting element and traveling toward the detection region is substantially parallel to an imaginary line connecting the end faces of the reflector.
  20. 　さらに、
    　前記投光素子及び前記受光素子が配置された筐体と、
    　前記筐体内に設けられ、かつ、前記検知領域を含む空間領域であって粒子を含む大気が流れる空間領域である粒子流路と、
    　前記筐体内に設けられ、かつ、前記散乱光を前記受光素子に導くための空間領域である受光領域と、
    　前記粒子流路と前記受光領域との接続部分に配置され、かつ、透光性を有する第１保護板とを備える
    　請求項１に記載の粒子検出センサ。     further,
    A housing in which the light projecting element and the light receiving element are disposed;
    A particle flow path which is provided in the housing and is a space region including the detection region and through which air containing particles flows; and
    A light receiving region that is provided in the housing and is a spatial region for guiding the scattered light to the light receiving element;
    The particle detection sensor according to claim 1, further comprising a first protective plate disposed at a connection portion between the particle flow path and the light receiving region and having translucency.
  21. 　前記受光領域は、前記粒子流路との接続部分に開口部を有し、
    　前記第１保護板は、前記受光領域の前記開口部を覆うように配置されている
    　請求項２０に記載の粒子検出センサ。     The light receiving region has an opening at a connection portion with the particle channel,
    The particle detection sensor according to claim 20, wherein the first protection plate is disposed so as to cover the opening of the light receiving region.
  22. 　前記反射体は、前記第１保護板と前記受光素子との間に設けられている
    　請求項２０又は２１に記載の粒子検出センサ。     The particle detection sensor according to claim 20 or 21, wherein the reflector is provided between the first protection plate and the light receiving element.
  23. 　前記第１保護板は、さらに、前記粒子流路と光トラップ構造を有するトラップ部との接続部分にも配置されている
    　請求項２０～２２のいずれか１項に記載の粒子検出センサ。     The particle detection sensor according to any one of claims 20 to 22, wherein the first protection plate is further disposed at a connection portion between the particle channel and a trap portion having an optical trap structure.
  24. 　前記筐体には、前記第１保護板に付着した付着物を除去するための清掃具が導入される清掃具導入孔が設けられている
    　請求項２０～２３のいずれか１項に記載の粒子検出センサ。     The particle according to any one of claims 20 to 23, wherein the casing is provided with a cleaning tool introduction hole into which a cleaning tool for removing the deposits attached to the first protective plate is introduced. Detection sensor.
  25. 　さらに、前記投光素子の光が投光される空間領域である投光領域と前記粒子流路との接続部分に配置された第２保護板を有する
    　請求項２０～２４のいずれか１項に記載の粒子検出センサ。     25. The apparatus according to any one of claims 20 to 24, further comprising a second protective plate disposed at a connection portion between a light projecting region that is a space region in which light of the light projecting element is projected and the particle flow path. The particle detection sensor described.
  26. 　前記第１保護板と前記第２保護板とで形成される空間は、前記粒子流路の一部を形成し、且つ、前記検知領域の幅と一致する
    　請求項２５に記載の粒子検出センサ。     The particle detection sensor according to claim 25, wherein a space formed by the first protection plate and the second protection plate forms part of the particle flow path and coincides with the width of the detection region.
  27. 　さらに、前記加熱装置から放出されるヒータ光及び外光の少なくとも一方を遮光する遮光体とを備え、
    　前記遮光体は、前記散乱光が当該遮光体に到達した場合に、当該散乱光が前記検知領域に反射することを抑制する形状を有する
    　請求項１に記載の粒子検出センサ。     And a light-shielding body that shields at least one of heater light and external light emitted from the heating device,
    The particle detection sensor according to claim 1, wherein the light blocking body has a shape that suppresses reflection of the scattered light to the detection region when the scattered light reaches the light blocking body.
  28. 　請求項１～２７のいずれか１項に記載の粒子検出センサを搭載している
    　ダストセンサ。     A dust sensor equipped with the particle detection sensor according to any one of claims 1 to 27.
  29. 　請求項１～２７のいずれか１項に記載の粒子検出センサを搭載している
    　煙感知器。     A smoke detector equipped with the particle detection sensor according to any one of claims 1 to 27.
  30. 　請求項１～２７のいずれか１項に記載の粒子検出センサ、又は、請求項２８に記載のダストセンサを搭載している
    　空気清浄機。     An air cleaner equipped with the particle detection sensor according to any one of claims 1 to 27 or the dust sensor according to claim 28.
  31. 　請求項１～２７のいずれか１項に記載の粒子検出センサ、又は、請求項２８に記載のダストセンサを搭載している
    　換気扇。     A ventilation fan equipped with the particle detection sensor according to any one of claims 1 to 27 or the dust sensor according to claim 28.
  32. 　請求項１～２７のいずれか１項に記載の粒子検出センサ、又は、請求項２８に記載のダストセンサを搭載している
    　エアコン。     An air conditioner equipped with the particle detection sensor according to any one of claims 1 to 27 or the dust sensor according to claim 28.
PCT/JP2015/001835 2014-04-03 2015-03-30 Particle-detecting sensor, dust sensor, smoke detector, air purifier, fan, and air conditioner WO2015151502A1 (en)

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