JP2017138223A - Minute object detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a minute object detector allowing a first light receiving element to detect intensity of scattered light from a particle by preventing stray light generated by reflection light from a second light receiving element when the second light receiving element monitors a variation in irradiation light.SOLUTION: A minute object detector includes: a first light receiving element 6 for detecting intensity of scattered light by receiving scattered light that is scattered by collision of irradiation light 3 from a light irradiation light against a particle; a count part for counting the number of particles, on the basis of intensity of scattered light output by the first light receiving element 6; a second light receiving element 9 for detecting intensity of the irradiation light 3; and a first beam trap 7 provided between a passage area P of particles and the second light receiving element 9 to attenuate the irradiation light 3 passing through the passage area P of particles. The second light receiving element 9 is disposed such that a normal direction of a light reception surface of the second light receiving element 9 deviates from a light axis direction of the irradiation light 3 by a predetermined angle.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a minute object detection device having a function of detecting particles floating in the atmosphere or particles floating in a liquid.

  Irradiate light into a space where there are floating particulate substances (hereinafter referred to as “particles”) such as pollen or dust, and the scattered light generated at that time is detected. Various micro object detection apparatuses that detect the size or the type of particles have been proposed.

  For example, Patent Document 1 includes a light-emitting element, a first light-receiving element, a second light-receiving element, and an optical trap unit, irradiates particles with irradiation light emitted from the light-emitting element, and applies the scattered light to the first Irradiation is performed by detecting the presence of particles by receiving light with the light receiving element, and providing the second light receiving element in the light trap part, and the second light receiving element receives the irradiation light and monitors the amount of the irradiation light. A particle sensor that estimates fluctuations in the amount of light and contamination of an optical system such as a light emitting element is disclosed.

JP-A-8-271424 (page 3-4, Fig. 1)

  However, in the technique described in Patent Document 1 described above, since the second light receiving element provided in the optical trap portion is disposed to face the light emitting element, the irradiation light from the light emitting element is the second light receiving element. , The irradiated light is reflected on the surface of the second light receiving element, and reflected light is generated in the incident direction. Part of this reflected light is attenuated by the optical trap part, but in particular, the reflected light emitted in the optical axis direction of the irradiated light does not get blocked by the optical trap part, so it reaches the particle detection region. Then, it becomes stray light and reaches the first light receiving element. In particular, in a particle sensor having a condensing mirror for efficiently guiding scattered light to the first light receiving element, the influence of this stray light is large on the scattered light from the particles received by the first light receiving element. Thus, there is a problem that the optical S / N ratio of the first light receiving element is deteriorated.

  The present invention has been made to solve the above-described problem, and prevents stray light generated by reflected light from the second light receiving element when the fluctuation of the amount of irradiation light is monitored by the second light receiving element. And providing a minute object detection device capable of detecting particles with high reliability by detecting the intensity of scattered light from the particles received by the first light receiving element without being affected by the stray light. With the goal.

  The fine object detection device according to the present invention receives a light irradiation unit that irradiates particles in a gas or a liquid with irradiation light, and receives scattered light scattered by the irradiation light hitting the particles, and determines the intensity of the scattered light. The number of the particles is counted based on a first light receiving element to be detected, a condensing mirror for guiding the scattered light to the first light receiving element, and an intensity of the scattered light output from the first light receiving element. A counting unit; a second light receiving element that detects the intensity of the irradiation light; and the irradiation light that is provided between the particle passing region and the second light receiving element and passes through the particle passing region. A first beam trap to be attenuated, and the second light receiving element is disposed so that a normal direction of a light receiving surface of the second light receiving element is shifted by a predetermined angle with respect to an optical axis direction of the irradiation light. It is characterized by.

  According to the present invention, the stray light generated by the reflected light from the second light receiving element can be prevented when the second light receiving element monitors fluctuations in the amount of irradiation light, and therefore is affected by stray light. Without detecting the intensity of the scattered light from the particles received by the first light receiving element, it is possible to detect the particles with high reliability.

It is a block diagram which shows schematically the structure of the micro object detection apparatus which concerns on Embodiment 1 of this invention. It is a block diagram which shows schematically the structure of the micro object detection apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows schematically the light ray of the 1st path | route of the micro object detection apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows schematically the light ray of the 2nd path | route of the micro object detection apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows schematically the light ray of the 3rd path | route of the micro object detection apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows schematically the path | route of the light ray which goes to the 2nd light receiving element of the micro object detection apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows schematically the path | route of the light ray which goes to the 2nd light receiving element of the micro object detection apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows schematically the path | route of the light ray which goes to the 2nd light receiving element of the micro object detection apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows schematically the path | route of the light ray which goes to the 2nd light receiving element of the micro object detection apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows schematically the path | route of the light ray which goes to the 2nd light receiving element of the micro object detection apparatus which concerns on Embodiment 2 of this invention. It is a figure which shows schematically the path | route of the light ray which goes to the 2nd light receiving element of the micro object detection apparatus which concerns on Embodiment 3 of this invention. It is a figure which shows schematically the path | route of the light ray which goes to the 2nd light receiving element of the micro object detection apparatus which concerns on Embodiment 4 of this invention. It is a figure which shows schematically the path | route of the light ray which goes to the 2nd light receiving element of the micro object detection apparatus which concerns on Embodiment 4 of this invention. It is a figure which shows schematically the path | route of the light ray which goes to the 2nd light receiving element of the micro object detection apparatus which concerns on Embodiment 5 of this invention.

  For ease of explanation, the coordinate axes of the XYZ orthogonal coordinate system are shown in each figure. In the following description, the direction in which the center of the intake port 5a and the center of the exhaust port 5b of the minute object detection device 11 are formed is defined as the X-axis direction. The intake port 5a side is the + X-axis direction. The exhaust port 5b side is the −X axis direction. Let the direction which divides the center of the 1st condensing mirror 101 and the center of the 2nd condensing mirror 102 be a Y-axis direction. The first condenser mirror 101 side is the + Y axis direction. The second condensing mirror 102 side is the −Y axis direction. The direction in which the irradiation light 3 is irradiated is defined as the Z-axis direction. The direction in which the irradiation light 3 travels is the + Z-axis direction. The side on which the laser light emitting element 1 is disposed is the −Z axis direction.

Embodiment 1 FIG.
1 and 2 are configuration diagrams schematically showing the configuration of the minute object detection apparatus 11 according to Embodiment 1 of the present invention. FIG. 1 is a configuration diagram illustrating the YZ plane of the minute object detection device 11. FIG. 2 is a configuration diagram illustrating the XZ plane of the minute object detection device 11.

  As shown in FIGS. 1 and 2, the minute object detection device 11 includes a laser light emitting element 1, a first light collecting mirror 101, a second light collecting mirror 102, and a first light receiving element 6 as main components. , A second light receiving element 9, an intake port 5a, and an exhaust port 5b. Further, the minute object detection device 11 can include a second light receiving element holding unit 4 and an irradiation unit holding unit 91.

  The laser beam irradiation unit 10 is a light irradiation unit that irradiates particles in gas or liquid with irradiation light. The laser light irradiation unit 10 includes a laser light emitting element 1. The laser light irradiation unit 10 can include the lens 2 and the irradiation unit holding unit 91. The laser light emitting element 1 is a light source. The lens 2 guides the light emitted from the laser light emitting element 1 to the detection region D. The detection area D is an area surrounded by the first condenser mirror 101 and the second condenser mirror 102. The lens 2 emits light emitted from the laser light emitting element 1 as irradiation light 3 for the particles to be examined. The irradiation unit holding unit 91 holds the laser light emitting element 1 and the lens 2. That is, the irradiation unit holding unit 91 integrates the laser light emitting element 1 and the lens 2.

  In the first embodiment, laser light emitted from the laser light emitting element 1 (hereinafter referred to as irradiation light 3) enters the lens 2. For example, the lens 2 collects the incident irradiation light 3. Alternatively, the lens 2 converts the incident irradiation light 3 into parallel light, for example.

  Irradiation light 3 emitted from the lens 2 is guided to the detection region D by the lens 2. The irradiation light 3 guided to the detection area D is, for example, a condensed light state or a collimated light state. For example, the lens 2 may be a cylindrical lens having a condensing function.

  There are airborne particles in the detection region D. In the case where the intensity of the irradiation light 3 can be set sufficiently large for detection of suspended particles, the lens 2 can be omitted.

  As described above, the particles are fine particulate substances that float. The particles are, for example, pollen or dust. The particles include dead bodies such as ticks or fragments thereof. The particles include so-called fine particulate PM2.5. PM2.5 is a small particle having a particle size of 2.5 μm or less among small particles floating in the atmosphere. The component of PM2.5 contains carbon, nitrate, sulfate, ammonium salt, inorganic elements such as silicon, sodium or aluminum.

  In Embodiment 1, a light source is described as a laser light source. However, the light source may be, for example, an LED (Light Emitting Diode). In this case, the irradiation light 3 is LED light or the like. Further, the irradiation light 3 may be monochromatic light or white light.

  The detection optical system 20 includes a first light receiving element 6, a first condenser mirror 101, and a second condenser mirror 102. The first light receiving element 6 receives the scattered light scattered by the irradiation light 3 hitting the particles, and detects the output light amount that is the intensity of the scattered light. The first condenser mirror 101 and the second condenser mirror 102 guide part of the scattered light to the first light receiving element 6. The first condenser mirror 101 is, for example, an elliptical mirror. Moreover, the 2nd condensing mirror 102 is a spherical mirror, for example. The first condenser mirror 101 and the second condenser mirror 102 may be a partial area of one condenser mirror.

  The “scattered light” is light that is generated when the irradiation light 3 hitting the suspended particles changes its propagation state. “Propagation” means that a wave spreads in a medium. Here, light travels through space. The space is in air, liquid, or vacuum. However, “scattered light” includes fluorescence of suspended particles generated by the wavelength of the irradiation light 3.

  The first condenser mirror 101 reflects the scattered light 111a directly incident from the particles and guides it to the light receiving element 6 by using the positions of the two focal points of the ellipse. For example, the particles are guided to the position of one focal point (first focal point) of the first condenser mirror 101. Then, the light receiving element 6 is disposed at another focal point (second focal point) of the first condenser mirror 101.

  The second collector mirror 102 reflects the scattered light 113a directly incident from the particles by using the position of the spherical focal point, and further reflects by the first collector mirror 101 to the first light receiving element 6. Lead. For example, the focal point of the second condenser mirror 102 (the center point of the radius of curvature of the spherical mirror surface) is arranged at the position of the first focal point of the first condenser mirror 101. Thereby, the reflected light of the second condenser mirror 102 is further reflected by the first condenser mirror 101 and guided to the first light receiving element 6.

  The intake port 5a is a suction nozzle. The exhaust port 5b is a discharge nozzle. The air inlet 5a guides an air test object or a liquid test object containing particles to be detected to the detection area D. Further, the exhaust port 5b discharges an air test object or a liquid test object containing particles to be detected from the detection area D. A particle passage region P is formed between the intake port 5a and the exhaust port 5b.

  The second light receiving element holding unit 4 is configured by a second light receiving element 9, a first beam trap 7, and a second beam trap 8. The second light receiving element 9 detects the output light amount that is the intensity of the irradiation light 3 and monitors the fluctuation of the output light amount. The second light receiving element 9 faces the −Y axis direction by a predetermined angle so as to be inclined with respect to the incident direction of the irradiation light 3. That is, the second light receiving element 9 receives the second light with respect to the Z-axis direction (the optical axis direction of the irradiated light 3) in which the irradiation light 3 that has passed through the particle passage region P enters the second light receiving element 9. The normal direction of the light receiving surface of the element 9 is arranged so as to deviate by a predetermined angle. Note that the second light receiving element 9 only needs to be tilted with respect to the Z-axis direction, and therefore the direction thereof need not be limited to the −Y-axis direction.

  The first beam trap 7 is provided between the particle passage region P and the second light receiving element 9 and attenuates the irradiation light 3 that has passed through the particle passage region P. The first beam trap 7 prevents the irradiation light 3 having passed through the particle passage region P from being reflected back to the passage region P as reflected light. The inner wall of the first beam trap 7 has a conical shape so that the inner diameter becomes narrower as it goes in the + Z direction, and the irradiation light 3 and the reflection light are attenuated by repeating the reflection of the irradiation light 3 on the wall surface of the cone. It has a structure. Since the 1st beam trap 7 should just be a structure which attenuates the irradiation light 3 and reflected light, it is not specifically limited to a cone shape. An opening H1 is provided at the end of the first beam trap 7 in the + Z direction. The opening H <b> 1 is provided so as to face the second light receiving element 9.

  The second beam trap 8 prevents the irradiation light 3 reflected on the light receiving surface side of the second light receiving element 9 from being reflected back to the passage region P as reflected light. The second beam trap 8 is provided in a direction in which the irradiation light 3 is reflected on the light receiving surface of the second light receiving element 9. The second beam trap 8 is arranged on the −Y axis direction side where the irradiation light 3 is reflected by the light receiving surface of the second light receiving element 9. The second beam trap 8 only needs to be arranged in a direction in which the second light receiving element 9 is inclined, and thus does not need to be arranged on the −Y axis direction side. The second beam trap 8 has a structure in which the reflected light is repeatedly reflected on the inner wall of the second beam trap 8 to attenuate the reflected light, and the reflected light does not return to the passing region P. Yes.

  A reflective region S is provided on the light receiving surface side of the second light receiving element 9, and the opening H1 of the first beam trap 7 and the opening H2 of the second beam trap 8 are connected to the reflective region S, respectively. .

  The first light receiving element 6 and the second light receiving element 9 output a current or voltage corresponding to the intensity of light. The first light receiving element 6 and the second light receiving element 9 have a light receiving region for receiving light. The first light receiving element 6 and the second light receiving element 9 are, for example, photodiodes. The first light receiving element 6 and the second light receiving element 9 are configured by a semiconductor element having a function as a light receiving sensor, a case enclosing the semiconductor element, a cover that covers the semiconductor element and transmits light, and the like. This cover is a light receiving surface of the first light receiving element 6 and the second light receiving element 9, and is formed of glass, plastic or the like.

  When the outputs of the first light receiving element 6 and the second light receiving element 9 are currents, the micro object detection device 11 sets the current value to the subsequent stage of the first light receiving element 6 and the second light receiving element 9. An IV conversion circuit (current / voltage conversion circuit) that converts the voltage may be provided.

  On the other hand, when the outputs of the first light receiving element 6 and the second light receiving element 9 are voltages, the minute object detection device 11 converts the first light receiving element 6 and the second light receiving element 6 into a stable voltage. A buffer circuit can be provided downstream of the light receiving element 9. The buffer circuit is, for example, a voltage follower.

  The first light receiving element 6 is connected to a detection circuit (not shown), and the detection circuit calculates the number of particles based on the voltage or current output from the first light receiving element 6 corresponding to the intensity of the scattered light. It has a counting part. As a method of counting the number of particles, there is a method of detecting the maximum peak point of the output signal from the first light receiving element 6 and counting the number of maximum peak points. Since the maximum peak point corresponds to a particle, the number of particles can be counted.

  The second light receiving element 9 is for monitoring the output light amount of the laser light emitting element 1. The output of the second light receiving element 9 is proportional to the output light amount of the laser light emitting element 1. For this reason, when the output of the second light receiving element 9 fluctuates, the output light amount of the laser light emitting element 1 can be made constant by feedback controlling the output of the second light receiving element 9, and the micro object detection device 11 detection sensitivity can be made constant.

  Next, the behavior of the light beam when the irradiation light 3 is guided to the detection region D will be described. The detection area D is an area in a gas such as air. Alternatively, the detection area D is an area in a liquid such as water. Alternatively, the detection area D is a vacuum area. The particle passage region P in the detection region D may be a region closed by a wall or the like through which the irradiation light 3 passes. Alternatively, the particle passing region P in the detection region D may be an open region.

  The particles to be detected are not particularly limited as long as they are minute substances that generate scattered light when irradiated with the irradiation light 3.

  When an air test object or a liquid test object including particles to be detected is introduced to the detection area D from the intake port 5a, the particles to be detected pass through the detection area D. In Embodiment 1, particles pass through the detection region D from the + X axis side toward the −X axis side. The irradiation light 3 is applied to the particles. At this time, scattered light is generated from the particles.

  In the detection optical system 20 of the minute object detection apparatus 11 according to Embodiment 1, there are three types of paths through which scattered light generated by particles is guided to the light receiving element 6.

  3, 4, and 5 are diagrams schematically illustrating the path of the light beam in the minute object detection device 11. FIG. 3 shows the first path. FIG. 4 shows the second route. FIG. 5 shows the third route. In FIG. 3, FIG. 4, and FIG. 5, only representative rays of scattered light are shown in order to reduce the complexity of the drawing.

  In FIG. 3, the light beam 111 a scattered by the particles reaches the first condenser mirror 101. The light beam 111 a that has reached the first condenser mirror 101 is reflected by the first condenser mirror 101. The light beam 111 b reflected by the first condenser mirror 101 reaches the first light receiving element 6. This route is referred to as a first route.

  In FIG. 3, the behavior of the light beam is shown by representative light beams 111a and 111b among the scattered light beams. The light beam 111 a is a light beam in which scattered light enters the first condenser mirror 101 from the particle. The light beam 111 b is a light beam of reflected light that is reflected by the first condenser mirror 101. The reflected light 111 b is guided to the first light receiving element 6.

  In FIG. 4, the light beam 112 scattered by the particles directly reaches the first light receiving element 6. That is, the light beam 112 is not reflected by the first condenser mirror 101 or the second mirror 102. This route is referred to as a second route.

  In FIG. 4, the behavior of the light beam is indicated by a representative light beam 112 among the scattered light beams. The light beam 112 is a light beam in which scattered light directly reaches the first light receiving element 6 from the particle. Therefore, the light beam 112 reaches the light receiving element 6 without passing through the first condenser mirror 101 or the second mirror 102.

  In FIG. 5, the light beam 113 a scattered by the particles reaches the second collector mirror 102. The light beam 113 a that has reached the second collector mirror 102 is reflected by the second collector mirror 102. The light beam 113 b reflected by the second condenser mirror 102 reaches the first condenser mirror 101. The light beam 113 b that has reached the first collector mirror 101 is reflected by the first collector mirror 101. The light beam 113 c reflected by the first condenser mirror 101 reaches the first light receiving element 6. This route is referred to as a third route.

  In FIG. 5, the behavior of the light beam is shown by representative light beams 113a, 113b, and 113c among the scattered light beams. The light beam 113a is a light beam in which scattered light travels from the particle toward the second collector mirror 102. The light beam 113 b is a light beam of reflected light that is reflected by the second condenser mirror 102. The light beam 113 c is a light beam of reflected light that is reflected by the first condenser mirror 101. The light beam 113 c is guided to the first light receiving element 6.

  Next, the relationship between the irradiation light 3 and the second light receiving element 9 in the second light receiving element holding part 4 will be described. 6 and 7 are diagrams schematically showing the path of the light beam 3 of the irradiation light 3 toward the second light receiving element 9 of the minute object detection device 11. 6 and 7, the area around the second light receiving element holding unit 4, the first beam trap 7, the second beam trap 8, and the second light receiving element 9 is shown in an enlarged manner. In order to reduce the complexity of the figure, only representative rays of the irradiation light 3 are shown. 6 and 7 indicates the optical axis of the irradiation light 3.

  FIG. 6 shows the behavior of the light beam on the outer periphery of the optical axis of the irradiation light 3. The light beam 201 a on the outer periphery of the optical axis of the irradiation light 3 that has passed through the particle passage region P reaches the first beam trap 7. The light beam 201 a that has reached the first beam trap 7 is reflected by the wall surface of the first beam trap 7. The light beam 201 b reflected by the wall surface of the first beam trap 7 reaches the wall surface of the first beam trap 7 that faces the beam 201 b. The light ray 201 c reflected by the wall surface of the first beam trap 7 reaches the wall surface of the first beam trap 7 that faces the beam 201 c. As described above, the light beam 201a on the outer periphery of the optical axis of the irradiation light 3 is attenuated while being repeatedly reflected on the wall surface of the first beam trap 7, so that stray light can be prevented.

  FIG. 7 shows the behavior of the light beam near the optical axis of the irradiation light 3. The light beam 202a in the vicinity of the optical axis of the irradiation light 3 that has passed through the particle passage region P passes through the opening H1 provided at the + Z direction end of the first beam trap 7. The light beam 202a that has passed through the opening H1 reaches the second light receiving element 9. A part of the light beam 202a reaching the second light receiving element 9 reaches the semiconductor element in the second light receiving element 9, and is converted into a current or voltage corresponding to the intensity of the irradiation light 3, and the output light amount of the irradiation light 3 Is detected.

  A part of the light beam 202 a reaching the second light receiving element 9 is reflected by the light receiving surface of the second light receiving element 9. The light beam 202b reflected by the second light receiving element 9 passes through the opening H2 provided at the + Y direction end of the second beam trap 8. The light beam 202b that has passed through the opening H2 reaches the wall surface of the second beam trap 8. The light beam 202 c reflected by the wall surface of the second beam trap 8 reaches the wall surface of the second beam trap 8 that faces the beam 202 c. As described above, the light beam 202b that has passed through the opening H2 is attenuated while being repeatedly reflected on the wall surface of the second beam trap 8, so that stray light can be prevented. The reflected light can be further attenuated by inclining the inner surface of the second beam trap 8.

  As described above, according to the microscopic object detection apparatus 11 of the first embodiment, the second light receiving element 9 is arranged at the back position in the first beam trap 7, and the direction of the second light receiving element 9 is set. Is tilted with respect to the optical axis direction of the irradiation light 3 (the Z-axis direction in which the irradiation light 3 is incident on the second light receiving element 9), and the reflected light of the irradiation light 3 generated by the second light receiving element 9 is The light is guided to the opening H 2 of the beam trap 8, and the reflected light is attenuated by the second beam trap 8. With such a configuration, when the output light quantity of the irradiation light 3 is detected by the second light receiving element 9, the reflected light of the irradiation light 3 generated by the second light receiving element 9 returns directly to the detection region D. Prevent stray light. Since the amount of scattered light due to the particles in the passage region P reaching the first light receiving element 6 is small, when stray light reaches the first light receiving element 6, the first light receiving element 6 scatters light according to the number of particles. Therefore, accurate particle detection cannot be performed. In particular, in the microscopic object detection apparatus 11 including the first condenser mirror 101 and the second condenser mirror 102 in order to efficiently guide the scattered light to the first photodetector 6, the first photodetector 6 includes the first condenser mirror 101 and the second condenser mirror 102. The effect of this stray light is increased with respect to scattered light from the light receiving particles, and the light receiving sensitivity of the first light receiving element 6 is deteriorated. However, stray light generated in the detection region D as in the first embodiment can be prevented, and the first light receiving element 6 can detect the intensity of scattered light from the particles without being affected by stray light. Therefore, highly reliable particle detection can be performed.

  The positional relationship between the second light receiving element 9 and the second beam trap 8 is such that the second light receiving element 9 reflects the light beam near the optical axis of the irradiation light 3 in the direction in which the second beam trap 8 is reflected. It is only necessary that the opening H2 is provided. Accordingly, the second beam trap 8 and its opening H2 are provided at a location that does not structurally interfere with the first beam trap 7, the second light receiving element 9 is disposed on the optical axis of the irradiation light 3, and the second If the direction of the light receiving surface of the second light receiving element 9 is inclined at a predetermined angle with respect to the optical axis direction of the irradiation light 3 so that the light receiving element 9 of the second light receiving element 9 reflects the irradiation light 3 toward the opening H2, Similar effects can be obtained.

  The first beam trap 7 and the second beam trap 8 are not limited as long as the incident light beam is reflected and does not return to the detection region D again, and confine light, absorb light, or light. The method is not limited to a method of releasing to the outside.

Modification 1
Hereinafter, a modified example of the stray light prevention configuration that replaces the second beam trap 8 will be described with reference to FIGS. 8 and 9. FIG. 8 shows a first modification of the second beam trap 8, and is a diagram schematically showing a path of a light beam toward the second light receiving element 9 of the minute object detection device 11. FIG. 9 shows a second modification of the second beam trap 8, and is a diagram schematically showing a path of a light beam toward the second light receiving element 9 of the minute object detection device 11. In FIGS. 8 and 9, only representative rays of the irradiation light 3 are shown in order to reduce the complexity of the drawings. Note that the light rays on the outer periphery of the optical axis of the irradiation light 3 passing through the particle passage region P are attenuated by the wall surface of the first beam trap 7 as in FIG.

  FIG. 8 shows the behavior of light rays in the vicinity of the optical axis of the irradiation light 3. The light beam 202a in the vicinity of the optical axis of the irradiation light 3 that has passed through the particle passage region P passes through the opening H1 provided at the + Z direction end of the first beam trap 7. The light beam 202a that has passed through the opening H1 reaches the second light receiving element 9. A part of the light beam 202a that has reached the second light receiving element 9 reaches the semiconductor element in the second light receiving element 9 and is converted into a current or voltage corresponding to the intensity of the light, and the output light amount of the irradiation light 3 is detected. Is done.

  A part of the light beam 202 a reaching the second light receiving element 9 is reflected by the light receiving surface of the second light receiving element 9. The light beam 202 b reflected by the light receiving surface of the second light receiving element 9 passes through the opening H <b> 3 provided on the −Y direction side of the second light receiving element 9. The light beam 202b that has passed through the opening H3 reaches the light absorber 31. The light absorber 31 converts light energy as heat energy, and examples thereof include black resin, metal, and paper. In this way, the light beam 202b that has reached the light absorption band 31 can prevent stray light because much light is absorbed as thermal energy.

Modification 2
FIG. 9 shows the behavior of light rays in the vicinity of the optical axis of the irradiation light 3. The light beam 202a in the vicinity of the optical axis of the irradiation light 3 that has passed through the particle passage region P passes through the opening H1 provided at the + Z direction end of the first beam trap 7. The light beam 202a that has passed through the opening H1 reaches the second light receiving element 9. A part of the light beam 202a that has reached the second light receiving element 9 reaches the semiconductor element in the second light receiving element 9 and is converted into a current or voltage corresponding to the intensity of the light, and the output light amount of the irradiation light 3 is detected. Is done.

  A part of the light beam 202 a reaching the second light receiving element 9 is reflected by the light receiving surface of the second light receiving element 9. The light beam 202 b reflected from the light receiving surface of the second light receiving element 9 passes through an opening H <b> 3 provided on the −Y direction side of the second light receiving element 9. The light beam 202b that has passed through the opening H3 passes through the opening H4 of the micro object detection device 11, is emitted to the outside of the micro object detection device 11, and does not return to the micro object detection device 11 again. The housing wall surface 30 is installed outside the minute object detection device 11, and ambient light such as sunlight or illumination may enter the minute object detection device 11 from the opening H <b> 4 of the minute object detection device 11. Absent. In this way, the light beam 202b is emitted from the opening H4 to the outside of the minute object detection apparatus 11 and the ambient light from the opening H4 is prevented by the housing wall surface 30, so that it is generated in the detection region D. It is possible to prevent stray light.

Embodiment 2. FIG.
In the first embodiment, the minute object detection device 11 of the present invention detects the output light amount of the irradiation light 3 by the second light receiving element 9 and prevents stray light due to the reflection of the irradiation light 3 generated by the second light receiving element 9. For this purpose, the configuration including the second beam trap 8 has been described. The second embodiment is different from the first embodiment in that the position of the second beam trap 18 is changed. FIG. 10 is a diagram schematically illustrating a path of a light beam traveling toward the second light receiving element 9 of the minute object detection device 11 according to the second embodiment. In FIG. 10, only representative rays of the irradiation light 3 are shown in order to reduce the complexity of the drawing.

  The second light receiving element holding portion 14 is constituted by a second light receiving element 9, a first beam trap 17, and a second beam trap 18. The second light receiving element 9 monitors the output light amount of the irradiation light 3. The second light receiving element 9 is inclined with respect to the optical axis direction of the irradiation light 3 (the Z-axis direction in which the irradiation light 3 enters the second light receiving element 9). To be arranged, it is directed in the −Y axis direction by a predetermined angle. Note that the second light receiving element 9 only needs to be tilted with respect to the Z-axis direction, and therefore the direction thereof need not be limited to the −Y-axis direction.

  The first beam trap 17 prevents the irradiation light 3 that has passed through the particle passage region P from being reflected back to the passage region P as reflected light. The first beam trap 17 has a conical inner wall so that the inner diameter becomes narrower as it goes in the + Z direction. The reflection of the irradiation light 3 is repeated on the wall surface of the cone to attenuate the irradiation light 3 and the reflection light. It has a structure. The first beam trap 17 is configured such that the + Z direction end of the first beam trap 17 is in contact with the light receiving surface of the second light receiving element 9.

  Further, the first beam trap 17 is provided with an opening H5 that is open on the −Y direction side on the wall surface near the + Z direction end portion or the wall surface on the + Z direction end portion side. The opening H5 is connected to the second beam trap 18. That is, the first beam trap 17 and the second beam trap 18 form a continuous space through the opening H5.

  The second beam trap 18 prevents the irradiation light 3 reflected on the light receiving surface side of the second light receiving element 9 from being reflected back to the passage region P as reflected light. The second beam trap 18 is arranged on the −Y axis direction side where the irradiation light 3 is reflected by the light receiving surface of the second light receiving element 9. The second beam trap 18 need only be arranged in the direction in which the second light receiving element 9 is inclined, and thus does not need to be arranged on the −Y axis direction side. The second beam trap 18 has a structure in which reflected light is repeatedly reflected on the inner wall of the second beam trap 18 to attenuate the reflected light, and the reflected light does not return to the passing region P. Yes.

  In the minute object detection device 11 according to Embodiment 2, the relationship between the irradiation light 3 and the second light receiving element 9 in the second light receiving element holding unit 14 will be described with reference to FIG. Note that the light beam on the outer periphery of the optical axis of the irradiation light 3 that has passed through the particle passage region P is attenuated by the wall surface of the first beam trap 7 as in the first embodiment, and thus the description thereof is omitted.

  FIG. 10 shows the behavior of the light beam near the optical axis of the irradiation light 3. The light beam 202 a near the optical axis of the irradiation light 3 that has passed through the particle passage region P passes through the + Z direction end of the first beam trap 17 and reaches the second light receiving element 9. A part of the light beam 202a that has reached the second light receiving element 9 reaches the semiconductor element in the second light receiving element 9 and is converted into a current or voltage corresponding to the intensity of the light, and the output light amount of the irradiation light 3 is detected. Is done.

  A part of the light beam 202 a reaching the second light receiving element 9 is reflected by the light receiving surface of the second light receiving element 9. The light beam 202b reflected by the light receiving surface of the second light receiving element 9 passes through the opening H5 of the first beam trap 17. The light beam 202b that has passed through the opening H5 reaches the wall surface of the second beam trap 18. 202 c reflected by the wall surface of the second beam trap 18 reaches the wall surface of the second beam trap 18 that is opposed. In this way, the light beam 202c that has passed through the opening H5 is attenuated while being repeatedly reflected on the wall surface of the second beam trap 18, so that stray light can be prevented. The reflected light can be further attenuated by inclining the inner surface of the second beam trap 18.

  As described above, according to the microscopic object detection apparatus 11 of the second embodiment, the second light receiving element 9 is arranged at the back position in the first beam trap 17, and the direction of the second light receiving element 9 is set. Is tilted with respect to the optical axis direction of the irradiation light 3 (the Z-axis direction in which the irradiation light 3 is incident on the second light receiving element 9), and the reflected light of the irradiation light 3 generated by the second light receiving element 9 is changed to the opening H5. Then, the reflected light is attenuated by the second beam trap 18. With such a configuration, when the output light quantity of the irradiation light 3 is detected by the second light receiving element 9, the reflected light of the irradiation light 3 generated by the second light receiving element 9 returns directly to the detection region D. Prevent stray light. Since the amount of scattered light due to the particles in the passage region P reaching the first light receiving element 6 is small, when stray light reaches the first light receiving element 6, the first light receiving element 6 scatters light according to the number of particles. Therefore, accurate particle detection cannot be performed. However, stray light generated in the minute body detection device as in the second embodiment can be prevented, and the first light receiving element 6 can detect the intensity of scattered light from the particles without being affected by stray light. Therefore, highly reliable particle detection can be performed.

  Further, an opening H5 that guides the reflected light from the light receiving surface of the second light receiving element 9 to the second beam trap 18 is provided in the wall surface of the first beam trap 17, so that the second beam trap 18 is disposed. Can be shortened in the + Z direction, the second light receiving element holding portion 14 can be shortened, and the apparatus can be miniaturized.

Embodiment 3 FIG.
The third embodiment is different from the first embodiment in that the reflected light from the second light receiving element 9 is blocked by the light shielding plate 71 provided in the first beam trap 27. FIG. 11 is a diagram schematically illustrating a path of a light beam toward the second light receiving element 9 of the minute object detection device 11 according to the third embodiment. In FIG. 11, only representative rays of the irradiation light 3 are shown in order to reduce the complexity of the drawing.

  The second light receiving element holding unit 24 is configured by the second light receiving element 9 and the first beam trap 27. The second light receiving element 9 monitors the output light amount of the irradiation light 3. The second light receiving element 9 is inclined with respect to the optical axis direction of the irradiation light 3 (the Z-axis direction in which the irradiation light 3 enters the second light receiving element 9). To be arranged, it is directed in the −Y axis direction by a predetermined angle. Note that the second light receiving element 9 only needs to be tilted with respect to the Z-axis direction, and therefore the direction thereof need not be limited to the −Y-axis direction.

  The first beam trap 27 prevents the irradiation light 3 that has passed through the particle passage region P from being reflected back to the passage region P as reflected light. The first beam trap 27 has a conical inner wall so that the inner diameter becomes narrower as it proceeds in the + Z direction, and the reflection of the irradiation light 3 is repeated on the wall surface of the cone to attenuate the irradiation light 3 and the reflection light. It has a structure. The first beam trap 27 includes a light shielding plate 71 in the + Y direction at the −Z direction end (the end in the direction in which the irradiation light enters). The light shielding plate 71 is disposed so as to shield the reflected light reflected by the light receiving surface of the second light receiving element 9.

  In the minute object detection device 11 according to Embodiment 3, the relationship between the irradiation light 3 and the second light receiving element 9 in the second light receiving element holding unit 24 will be described with reference to FIG. Note that the light beam on the outer periphery of the optical axis of the irradiation light 3 that has passed through the particle passage region P is attenuated by the wall surface of the first beam trap 7 as in the first embodiment, and thus the description thereof is omitted.

  FIG. 11 shows the behavior of the light beam near the optical axis of the irradiation light 3. The light beam 202 a in the vicinity of the optical axis of the irradiation light 3 that has passed through the particle passage region P passes through the + Z direction end of the first beam trap 27 and reaches the second light receiving element 9. A part of the light beam 202a that has reached the second light receiving element 9 reaches the semiconductor element in the second light receiving element 9 and is converted into a current or voltage corresponding to the intensity of the light, and the output light amount of the irradiation light 3 is detected. Is done.

  A part of the light beam 202 a reaching the second light receiving element 9 is reflected by the light receiving surface of the second light receiving element 9. The light beam 202 b reflected by the light receiving surface of the second light receiving element 9 returns again to the first beam trap 27 and reaches the wall surface of the first beam trap 27. The light beam 202 d reflected by the wall surface of the first beam trap 27 reaches the wall surface of the first beam trap 27 facing the first beam trap 27. The light beam 202 e reflected by the wall surface of the first beam trap 27 reaches the light shielding plate 71. As described above, the light beam 202 d reflected by the light receiving surface of the second light receiving element 9 and returned to the first beam trap 27 is blocked by the light shielding plate 71 while being attenuated by the first beam trap 27. It is possible to prevent the reflected light from returning directly to the detection area D and to prevent stray light.

  As described above, according to the minute object detection device 11 of the third embodiment, the second light receiving element 9 is arranged at the back position in the first beam trap 27, and the direction of the second light receiving element 9 is set. Is tilted with respect to the optical axis direction of the irradiation light 3 (the Z-axis direction in which the irradiation light 3 is incident on the second light receiving element 9), and the reflected light of the irradiation light 3 generated by the second light receiving element 9 is again reflected to the first. The reflected light is attenuated by the first beam trap 27 and blocked by a light shielding plate 71 provided in the first beam trap 27. With such a configuration, when the output light quantity of the irradiation light 3 is detected by the second light receiving element 9, the reflected light of the irradiation light 3 generated by the second light receiving element 9 returns directly to the detection region D. Prevent stray light. Since the amount of scattered light due to the particles in the passage region P reaching the first light receiving element 6 is small, when stray light reaches the first light receiving element 6, the first light receiving element 6 scatters light according to the number of particles. Therefore, accurate particle detection cannot be performed. However, stray light generated in the detection region D as in the first embodiment can be prevented, and the first light receiving element 6 can detect the intensity of scattered light from the particles without being affected by stray light. Therefore, highly reliable particle detection can be performed.

  Further, the reflected light from the light receiving surface of the second light receiving element 9 is attenuated by the first beam trap 27 and blocked by the light shielding plate 71 provided in the first beam trap 27, so that the second beam trap is Since it becomes unnecessary, the apparatus can be miniaturized.

Embodiment 4 FIG.
In the fourth embodiment, the reflection member 32 is provided in front of the second light receiving element 39, the direction of the optical axis of the irradiation light 3 is changed using the reflection member 32, and the irradiation light 3 is received by the light receiving surface of the reflection member 32. Is different from the first embodiment in that the light is reflected at the second light receiving element 39. FIG. 12 is a diagram schematically showing a path of light rays toward the second light receiving element 39 of the minute object detection device 11 according to the fourth embodiment. In FIG. 12, only representative rays of the irradiation light 3 are shown in order to reduce the complexity of the drawing.

  In FIG. 12, the second light receiving element holding portion 34 is configured by a second light receiving element 39, a first beam trap 7, a second beam trap 8, and a reflecting member 32. The first beam trap 7 and the second beam trap 8 are configured in the same manner as in the first embodiment, but a second light receiving element 39 is provided on the reflecting member 32 side of the second beam trap 8. ing.

  The reflecting member 32 has a function of reflecting the irradiation light 3 such as a mirror. The reflecting member 32 is provided between the first beam trap 7 and the second light receiving element 39, and reflects the irradiation light 3 toward the second light receiving element 39. The reflecting member 32 has a predetermined normal direction of the light receiving surface of the reflecting member 32 with respect to the Z-axis direction (the optical axis direction of the irradiating light 3) in which the irradiation light 3 passing through the particle passage region P enters the reflecting member 32. It is directed to the −Y-axis direction by a predetermined angle so as to be arranged with an angle shift and an inclination with respect to the incident direction of the irradiation light 3. Note that the reflecting member 32 only needs to be inclined with respect to the Z-axis direction, and therefore the direction thereof does not have to be limited to the −Y-axis direction.

  The irradiation light 3 reflected by the reflecting member 32 is incident on the second light receiving element 39. The second light receiving element 39 monitors the output light amount of the irradiation light 3. The second light receiving element 39 has the second light receiving element 39 with respect to the −Y-axis direction (the optical axis direction of the irradiated light 3) in which the irradiation light 3 reflected by the reflecting member 32 enters the second light receiving element 39. The normal line direction of the light receiving surface is shifted by a predetermined angle and is directed to the −Z-axis direction by a predetermined angle so as to be inclined with respect to the incident direction of the irradiation light 3. Note that the second light receiving element 39 only needs to be tilted with respect to the −Y axis direction, and therefore the direction thereof does not have to be limited to the −Z axis direction.

  In the minute object detection apparatus 11 according to Embodiment 5, the relationship between the irradiation light 3 in the second light receiving element holding unit 34, the reflecting member 32, and the second light receiving element 39 will be described with reference to FIG. Note that the light beam on the outer periphery of the optical axis of the irradiation light 3 that has passed through the particle passage region P is attenuated by the wall surface of the first beam trap 7 as in the first embodiment, and thus the description thereof is omitted.

  FIG. 12 shows the behavior of light rays in the vicinity of the optical axis of the irradiation light 3. The light beam 202a in the vicinity of the optical axis of the irradiation light 3 that has passed through the particle passage region P passes through the opening H1 provided at the + Z direction end of the first beam trap 7, reaches the reflecting member 32, and is reflected. Reflected by the light receiving surface of the member 32. The light beam 202a2 reflected by the light receiving surface of the reflecting member 32 passes through the opening H2 of the second beam trap 8, reaches the semiconductor element of the second light receiving element 39, and is a current or voltage corresponding to the light intensity. The output light amount of the irradiation light 3 is detected.

  A part of the light beam 202 a 2 that has reached the second light receiving element 39 is reflected by the light receiving surface of the second light receiving element 39. The light beam 202 h reflected by the light receiving surface of the second light receiving element 39 reaches the wall surface of the second beam trap 8 in the second beam trap 8. The light beam 202 h reflected by the wall surface of the second beam trap 8 reaches the wall surface of the second beam trap 8 that faces the beam 202 h. As described above, the light beam 202h reflected by the light receiving surface of the second light receiving element 39 is attenuated while repeating reflection on the wall surface of the second beam trap 8, and thus stray light can be prevented. The reflected light can be further attenuated by inclining the inner surface of the second beam trap 8.

  As described above, according to the microscopic object detection apparatus 11 of the fourth embodiment, the reflecting member 32 is arranged at the back position in the first beam trap 7, and the direction of the reflecting member 32 is the light of the irradiation light 3. Inclined with respect to the axial direction (Z-axis direction in which the irradiation light 3 enters the reflecting member 32), the reflected light of the irradiation light 3 is guided to the second light receiving element 39, and the direction of the second light receiving element 39 is set to the irradiation light. 3 is tilted with respect to the optical axis direction 3 (the Y-axis direction in which the reflected irradiation light 3 enters the light receiving element 39), and the reflected light is attenuated by the second beam trap 8. With such a configuration, when the output light quantity of the irradiation light 3 is detected by the second light receiving element 39, the reflected light of the irradiation light 3 generated by the second light receiving element 39 returns directly to the detection region D. Prevent stray light. Since the amount of scattered light due to the particles in the passage region P reaching the first light receiving element 6 is small, when stray light reaches the first light receiving element 6, the first light receiving element 6 scatters light according to the number of particles. Therefore, accurate particle detection cannot be performed. However, stray light generated in the detection region D as in the first embodiment can be prevented, and the first light receiving element 6 can detect the intensity of scattered light from the particles without being affected by stray light. Therefore, highly reliable particle detection can be performed.

  As shown in FIG. 13, instead of providing the reflection member 32, the reflection member may be configured using the same member as the second light receiving element holding portion 35. That is, you may utilize the 2nd light receiving element holding | maintenance part 35 provided with the reflective area | region 36 which reflects the irradiated light 3. FIG. By forming the second light receiving element holding portion 35 with a material that reflects light such as a metal material or resin, the irradiation light 3 can be reflected in the reflection region 36 where the irradiation light 3 is incident. Irradiation light can reach the light receiving element 39, and the output light quantity of the irradiation light 3 can be detected.

  Note that, in the configurations of the first to third embodiments, the same effects as those of the fourth embodiment can be obtained by applying the configuration of the fourth embodiment.

Embodiment 5. FIG.
In the first to fourth embodiments, the second light receiving element 49 is arranged to be inclined with respect to the optical axis direction of the irradiation light 3, and the irradiation light 3 is reflected using the light receiving surface of the second light receiving element 49. Changing direction. The fifth embodiment is different from the first embodiment in that a beam splitter 40 is provided in front of the second light receiving element 49 and the direction in which the irradiation light 3 is reflected is changed using the light receiving surface of the beam splitter 40. .

  FIG. 14 is a diagram schematically illustrating a path of a light beam toward the second light receiving element 49 of the minute object detection device 11 according to the fifth embodiment. In FIG. 14, the second light receiving element holding unit 44 is configured by a second light receiving element 49, a first beam trap 7, a second beam trap 8, and a beam splitter 40. The first beam trap 7 and the second beam trap 8 are configured in the same manner as in the first embodiment.

  The beam splitter 40 is an optical component that divides incident light into two lights at a predetermined division ratio. The beam splitter 40 is provided between the first beam trap 7 and the second light receiving element 49 and transmits part of the irradiation light 3. In the beam splitter 40, the normal direction of the light receiving surface of the beam splitter 40 is predetermined with respect to the Z-axis direction (the optical axis direction of the irradiation light 3) in which the irradiation light 3 that has passed through the particle passing region P enters the beam splitter 40. It is directed to the −Y-axis direction by a predetermined angle so as to be arranged with an angle shift and an inclination with respect to the incident direction of the irradiation light 3. Note that the beam splitter 40 only needs to be tilted with respect to the Z-axis direction, and therefore the direction thereof need not be limited to the −Y-axis direction.

  The second light receiving element 49 monitors the output light amount of the irradiation light 3. The second light receiving element 49 is arranged at the rear stage of the optical element 40 so that the light receiving surface of the second light receiving element 49 is perpendicular to the optical axis direction of the irradiation light 3. If the irradiation light 3 can be received, the second light receiving element 49 may not be installed so that the light receiving surface of the second light receiving element 49 is perpendicular to the optical axis of the irradiation light 3.

  In the minute object detection apparatus 11 according to Embodiment 5, the relationship between the irradiation light 3 in the second light receiving element holding unit 44, the beam splitter 40, and the second light receiving element 49 will be described with reference to FIG. Note that the light beam on the outer periphery of the optical axis of the irradiation light 3 that has passed through the particle passage region P is attenuated by the wall surface of the first beam trap 7 as in the first embodiment, and thus the description thereof is omitted.

  FIG. 14 shows the behavior of the light beam near the optical axis of the irradiation light 3. The light beam 202 a near the optical axis of the irradiation light 3 that has passed through the particle passage region P passes through the + Z direction end of the first beam trap 7 and reaches the beam splitter 40. A part of the light beam 202 a reaching the beam splitter 40 is transmitted through the beam splitter 40. The light beam 202g that has passed through the beam splitter 40 reaches the second light receiving element 49, is converted into a current or voltage corresponding to the intensity of the light, and the output light amount of the irradiation light 3 is detected.

  A part of the light beam 202 a that has reached the beam splitter 40 is reflected by the beam splitter 40. The light beam 202b reflected by the beam splitter 40 passes through the opening H2 of the second beam trap 8. The light beam 202b that has passed through the opening H2 reaches the wall surface of the second beam trap 8. The 202c reflected by the wall surface of the second beam trap 8 reaches the wall surface of the second beam trap 8 that is opposed. In this way, the light beam 202c that has passed through the opening H2 is attenuated while being repeatedly reflected on the wall surface of the second beam trap 8, so that stray light can be prevented. The reflected light can be further attenuated by inclining the inner surface of the second beam trap 8.

  Unlike the first embodiment, the irradiation light 3 is reflected by arranging the beam splitter 40 at an angle, so that the irradiation light 3 can be incident on the second light receiving element 49 in the vertical direction. In a general light receiving element, when the incident direction of light changes from the vertical direction to the horizontal direction, the light receiving sensitivity also decreases. Since the role of the second light receiving element 49 in the minute object detection device 11 is to monitor the fluctuation of the light amount of the irradiation light 3, the second light receiving element 49 is tilted from the optical axis direction of the irradiation light 3. There is no problem in that the light receiving sensitivity is lowered. However, when using a light receiving element having a strong directivity of light receiving sensitivity with respect to the incident direction of light, even if the light receiving element cannot be tilted due to restrictions on the structure of the second light receiving element holding portion, etc. While preventing stray light generated in the region D, it is possible to monitor fluctuations in the amount of the irradiation light 3.

  As described above, according to the microscopic object detection apparatus 11 of the fifth embodiment, the beam splitter 40 is arranged at the back position in the first beam trap 7, and the direction of the beam splitter 40 is set to the light of the irradiation light 3. Inclined with respect to the axial direction (Z-axis direction in which the irradiated light 3 enters the beam splitter 40), the reflected light of the irradiated light 3 generated by the beam splitter 40 is guided to the opening H2, and the reflected light is guided to the second beam trap 8. It is attenuated by. With such a configuration, when the output light quantity of the irradiation light 3 is detected by the second light receiving element 49, the reflected light of the irradiation light 3 generated by the second light receiving element 49 returns directly to the detection region D. Prevent stray light. Since the amount of scattered light due to the particles in the passage region P reaching the first light receiving element 6 is small, when stray light reaches the first light receiving element 6, the first light receiving element 6 scatters light according to the number of particles. Therefore, accurate particle detection cannot be performed. However, stray light generated in the detection region D as in the first embodiment can be prevented, and the first light receiving element 6 can detect the intensity of scattered light from the particles without being affected by stray light. Therefore, highly reliable particle detection can be performed.

  Note that, in the configurations of the first to fourth embodiments, the same effects as those of the fifth embodiment can be obtained by applying the configuration of the fifth embodiment.

  In each of the above-described embodiments, even when terms such as “parallel”, “vertical”, or “center” indicating the positional relationship between parts or the shape of the part are used, these are the manufacturing tolerances. And a range that takes into account variations in assembly. For this reason, even if “abbreviation” is not described in the claims, it includes a range that takes into account manufacturing tolerances and assembly variations.

  In addition, although embodiment of this invention was described as mentioned above, this invention is not limited to these embodiment.

DESCRIPTION OF SYMBOLS 1 Laser light emitting element 2 Lens 3 Irradiation light 4, 14, 24, 34, 35, 44 2nd light receiving element holding | maintenance part 5a Intake port 5b Exhaust port 6 1st light receiving element 7, 17, 27 1st beam trap 8 , 18 Second beam trap 9, 39, 49 Second light receiving element 10 Laser light irradiation unit 11 Minute object detection device 20 Detection optical system 30 Housing wall surface 31 Light absorber 32 Reflecting member 36 Reflecting region 40 Beam splitter 71 Light shielding Plate 91 Irradiation part holding part 101 1st condensing mirror 102 2nd condensing mirror 111a, 111b, 112, 113a, 113b, 113c Light ray 201a, 201b, 201c, 202a, 202a2, 202g to the 1st light receiving element Light rays 202b, 202d and 202e to the second light receiving element Light rays 202c reflected by the second light receiving element Light beam reflected by the wall surface of the beam trap 202h Light beam reflected by the reflecting member D Detected area H1, H2, H3, H4, H5 Opening O Optical axis of irradiated light P Passing area S Reflecting area

Claims (9)

A light irradiation unit for irradiating particles in gas or liquid with irradiation light;
A first light receiving element that receives scattered light scattered by the irradiation light hitting the particles and detects the intensity of the scattered light;
A condensing mirror for guiding the scattered light to the first light receiving element;
A counting unit for counting the number of particles based on the intensity of the scattered light output from the first light receiving element;
A second light receiving element for detecting the intensity of the irradiation light;
A first beam trap that is provided between the particle passage region and the second light receiving element and attenuates the irradiation light that has passed through the particle passage region;
The micro object detection device, wherein the second light receiving element is arranged so that a normal direction of a light receiving surface of the second light receiving element is shifted by a predetermined angle with respect to an optical axis direction of the irradiation light.   2. The minute object detection device according to claim 1, further comprising a second beam trap in a direction in which the irradiation light is reflected on a light receiving surface of the second light receiving element.   An opening is provided in a side wall of the first beam trap, and the second beam trap is provided so as to form a space continuous with the first beam trap through the opening. 2. The minute object detection device according to 2.   2. The first beam trap has a light shielding plate that shields reflected light reflected by a light receiving surface of the second light receiving element at an end in a direction in which the irradiation light is incident. Micro object detection device.   5. The reflector according to claim 1, further comprising a reflecting member that is provided between the first beam trap and the second light receiving element and reflects the irradiation light toward the second light receiving element. The micro object detection apparatus of any one of Claims. A light irradiation unit for irradiating particles in gas or liquid with irradiation light;
A first light receiving element that receives scattered light scattered by the irradiation light hitting the particles and detects the intensity of the scattered light;
A condensing mirror for guiding the scattered light to the first light receiving element;
A counting unit for counting the number of particles based on the intensity of the scattered light output from the first light receiving element;
A second light receiving element for detecting the intensity of the irradiation light;
A first beam trap provided between the particle passage region and the second light-receiving element, for attenuating the irradiation light passing through the particle passage region;
A beam splitter provided between the first beam trap and the second light receiving element and transmitting a part of the irradiation light;
The microscopic object detection apparatus, wherein the beam splitter is arranged so that a normal direction of a light receiving surface of the beam splitter is shifted by a predetermined angle with respect to an optical axis direction of the irradiation light.   The minute object detection apparatus according to claim 6, further comprising a second beam trap in a direction in which the irradiation light is reflected on a light receiving surface of the beam splitter.   An opening is provided in a side wall of the first beam trap, and the second beam trap is provided so as to form a space continuous with the first beam trap through the opening. 7. The micro object detection device according to 7.   7. The micro object according to claim 6, wherein the first beam trap has a light shielding plate that shields reflected light reflected by a light receiving surface of the beam splitter at an end in a direction in which the irradiation light is incident. Detection device.

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