Particle detector

Abstract

To provide a particle detector that can appropriately identify particles. [Solution] A sensor 1 for detecting particles in a detection space 101, comprising: a light-emitting element 121 that emits a first emitted light into the detection space 101; a first light-receiving element 122 that receives first scattered light generated when the first emitted light is scattered by particles in the detection space 101; and a processing unit that detects particles and / or determines whether the particles are monodisperse particles having a particle diameter within a predetermined particle diameter range smaller than the wavelength of the first emitted light, wherein the light-emitting element 121 emits polarized light having a polarization plane 121b parallel to a first scattering plane 911 determined by the optical axis 121a of the light-emitting element 121 and the optical axis 122a of the first light-receiving element 122 as the first emitted light.

Description

Technical Field

[0001] The present invention relates to a particle detector.

Background Art

[0002] Conventionally, a smoke detector for detecting a fire has been known (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, from the viewpoint of appropriately extinguishing a fire, it is necessary to extinguish the fire by an extinguishing method corresponding to the combustion target. That is, for example, when a semiconductor manufacturing gas burns, spraying water to extinguish the fire may generate toxic gas and is considered inappropriate, and the use of carbon dioxide or a powder fire extinguishing agent is required. Further, for example, in the case of a fire in a machine or a structure, extinguishing with water is generally possible as a normal fire.

[0005] On the other hand, in a conventional smoke detector, a fire has been detected by detecting the presence of particles based on scattered light generated by irradiating light on particles of combustion products. Therefore, it has been impossible to identify the type of combustion products, making it difficult to grasp the combustion target and potentially making it difficult to perform appropriate fire extinguishing.

[0006] Therefore, a technique for identifying particles has been desired.

[0007] The present invention has been made in view of the above problems, and an object thereof is to provide a particle detector capable of appropriately identifying particles.

Means for Solving the Problems

[0008] To solve the above-mentioned problems and achieve the objective, the particle detector described in claim 1 is a particle detector for detecting particles in a detection space, comprising: a first light-emitting unit that emits first emitted light into the detection space; a first light-receiving unit that receives first scattered light generated when the first emitted light is scattered by the particles in the detection space; and a processing unit that detects the particles and / or determines whether the particles are monodisperse particles having a particle diameter within a predetermined particle diameter range smaller than the wavelength of the first emitted light, wherein the first light-emitting unit emits polarized light having a polarization plane parallel to the scattering plane determined by the optical axis of the first light-emitting unit and the optical axis of the first light-receiving unit as the first emitted light, and the first light-receiving unit receives polarized light having a polarization plane parallel to the scattering plane among the scattered light generated when the first emitted light is scattered by the particles in the detection space, and polarized light at a scattering angle of 90 degrees with respect to the first emitted light as the first scattered light.

[0009] Furthermore, the particle detector according to claim 2 is a particle detector according to claim 1, further comprising a second light receiving unit that receives a second scattered light different from the first scattered light, and the processing unit, when it detects the presence of the particle based on the result of receiving the second scattered light by the second light receiving unit, determines whether the particle is the monodisperse particle based on the result of receiving the first scattered light by the first light receiving unit.

[0010] Furthermore, the particle detector according to claim 3 is the particle detector according to claim 2, wherein the second light receiving unit receives polarized light having a polarization plane perpendicular to the scattering plane determined by the optical axis of the first light emitting unit and the optical axis of the second light receiving unit as the second scattered light.

[0011] Furthermore, the particle detector according to claim 4 is a particle detector according to claim 1, comprising: a second light-emitting unit that emits a second light different from the first light into the detection space; and a second light-receiving unit that receives a second scattered light generated when the second light is scattered by the particles in the detection space, wherein the processing unit, when it detects the presence of the particles based on the result of receiving the second scattered light by the second light-receiving unit, determines whether the particles are monodisperse particles based on the result of receiving the first scattered light by the first light-receiving unit.

[0012] Furthermore, the particle detector according to claim 5 is the particle detector according to claim 4, wherein the second light-emitting unit emits polarized light as the second emitted light, having a polarization plane perpendicular to the scattering plane determined by the optical axis of the second light-emitting unit and the optical axis of the second light-receiving unit.

[0013] Furthermore, the particle detector according to claim 6 is the particle detector according to any one of claims 1 to 5, wherein the monodisperse particles are combustion products of semiconductor manufacturing gases. [Effects of the Invention]

[0014] According to the particle detector described in claim 1, it is possible to appropriately identify particles by detecting particles and / or determining whether the particles are monodisperse particles having a particle diameter within a predetermined particle diameter range smaller than the wavelength of the first emitted light.

[0015] According to the particle detector described in claim 2, when the presence of a particle is detected based on the reception result of the second scattered light by the second light receiving unit, it is possible to determine whether or not the particle is a monodisperse particle based on the reception result of the first scattered light by the first light receiving unit, thereby enabling appropriate detection and identification of the particle using, for example, two types of scattered light.

[0016] According to the particle detector described in claim 3, by receiving polarized light having a polarization plane perpendicular to the scattering plane determined by the optical axis of the first light emitting part and the optical axis of the second light receiving part as the second scattered light, for example, the intensity of the received second scattered light can be increased, so that particles can be reliably detected.

[0017] According to the particle detector described in claim 4, when the presence of particles is detected based on the light reception result of the second scattered light by the second light receiving part, by determining whether the particles are monodisperse particles based on the light reception result of the first scattered light by the first light receiving part, for example, it becomes possible to appropriately detect and identify the particles using two types of scattered light. Further, for example, by providing a second light emitting part that emits a second emitted light different from the first emitted light into the detection space, for example, a second emitted light suitable for detecting particles can be emitted, so that particles can be reliably detected.

[0018] According to the particle detector described in claim 5, by emitting polarized light having a polarization plane perpendicular to the scattering plane determined by the optical axis of the second light emitting part and the optical axis of the second light receiving part as the second emitted light, for example, the intensity of the second scattered light based on the second emitted light can be increased, so that particles can be reliably detected.

[0019] According to the particle detector described in claim 6, since the monodisperse particles are combustion products of the gas for semiconductor manufacturing, for example, it becomes possible to appropriately identify the combustion products of the gas for conductor manufacturing.

Brief Description of the Drawings

[0020] [Figure 1] It is a block diagram showing the sensor according to the present embodiment. [Figure 2] It is a diagram showing each element of the sensor. [Figure 3] It is an explanatory diagram of the scattering of light by particles. [Figure 4] It is a flowchart of disaster prevention processing. [Figure 5] It is a block diagram showing the sensor according to the present embodiment. [Figure 6] It is a diagram showing each element of a perceptron.

Embodiments of the Invention

[0021] Hereinafter, each embodiment of the particle detector according to the present invention will be described in detail based on the drawings. Note that the present invention is not limited by each of these embodiments.

[0022] 〔Basic Concepts of Embodiments〕 First, the basic concepts of each embodiment will be described. Each embodiment generally relates to a particle detector.

[0023] A "particle detector" is a device having a function of detecting particles.

[0024] A "particle" is a fine particle, and specifically, it is a concept including particles generated along with a fire, etc. For example, it is a concept including particles of water contained in smoldering smoke, particles of carbon contained in combustion smoke, and particles corresponding to gas combustion products such as gases for semiconductor manufacturing.

[0025] A "gas for semiconductor manufacturing" is a gas used for manufacturing semiconductors, and for example, it is a gas including silane gas (SiH4) or phosphine gas (PH3), etc.

[0026] "Particles corresponding to combustion products of gases for semiconductor manufacturing" refer to particles of silicon dioxide (SiO2) generated when silane gas burns, and P4O

[0028] , particles, etc.

[0027] The particle diameter of the particles of water contained in smoldering smoke is, for example, about 0.01 μm or more to 10 μm or less, and has a characteristic of relatively large variation in particle diameter. Also, the particles of carbon contained in combustion smoke are, for example, about 0.001 μm or more to several μm or less, and have a characteristic of relatively large variation in particle diameter.

[0028] On the other hand, silicon dioxide (SiO2) particles are generated when silane gas burns, and P4O is generated when phosphine gas burns. 10 The particle size of these particles is, for example, between 0.05 μm (50 nm) and 0.06 μm (60 nm), and is characterized by relatively uniform size (particle diameter) at relatively small particle sizes.

[0029] Furthermore, these silicon dioxide (SiO2) particles and P4O 10 The particles in question are classified as "monodisperse particles" because their particle sizes are relatively uniform. However, the water particles contained in the aforementioned smoke and the carbon particles contained in the combustion smoke do not qualify as "monodisperse particles" because their particle sizes vary considerably.

[0030] "Monodisperse particles" is a concept that refers to particles with relatively uniform particle sizes. Examples include silicon dioxide (SiO2) particles generated when silane gas is burned, and P4O particles generated when phosphine gas is burned. 10 This concept includes particles such as those mentioned above. While the range of particle size variation that determines whether a particle is "monodispersible" is arbitrary, for example, particles with a maximum difference in particle size between several tens of nanometers and several hundred nanometers or less may be considered monodispersible.

[0031] The following embodiments illustrate and explain how the concept of a particle detector is applied to a sensor to determine whether or not a particle corresponds to a combustion product of a semiconductor manufacturing gas (a particle of silicon dioxide (SiO2)). Specifically, the case where the "monodisperse particle" is a silicon dioxide particle will be explained.

[0032] [Specific details of the embodiment] Next, the specific details of the embodiment will be described.

[0033] (Embodiment 1) First, Embodiment 1 will be described. In this embodiment, the sensor will be described as comprising one light-emitting element and two light-receiving elements.

[0034] (composition) First, the configuration of the sensor according to this embodiment will be described. Figure 1 is a block diagram showing the sensor according to this embodiment, and Figure 2 is a diagram showing each element of the sensor.

[0035] The detector 1 in Figure 1 is the aforementioned particle detector, specifically a device for detecting fires occurring in a target area, and comprises, for example, a communication unit 11, a detection unit 12, a recording unit 13, and a control unit 14.

[0036] Since the detailed configuration of sensor 1 can be adapted from that of known sensors, this embodiment will describe in detail the configurations characteristic of this application, and will omit descriptions of other configurations.

[0037] The "target area" refers to the area where fire is to be detected, specifically the area where the detector 1 is installed, and is a concept that includes, for example, the area inside a factory building, and any other arbitrary area (including the area outside the building). In this embodiment, the case in which the target area is the area inside a semiconductor manufacturing plant building will be used as an example for explanation.

[0038] (Composition - Communications Department) The communication unit 11 in Figure 1 is a communication means for communicating with external devices (e.g., disaster prevention receivers). The communication unit 11 can be configured using, for example, a communication circuit.

[0039] (Configuration - Detection Unit) The detection unit 12 in Figure 1 is a component for detecting a fire in a target area, and includes, for example, a light-emitting element 121, a first light-receiving element 122, and a second light-receiving element 123. In this application, "element" refers to a component for performing a specific function, and is a concept that can refer to a single component or a collection of multiple components. The light-emitting element 121, the first light-receiving element 122, and the second light-receiving element 123 are also collectively referred to as "each element."

[0040] Each element of the detection unit 12 is provided within the detection space 101 of the detector 1, as shown in Figure 2. The "detection space" 101 is the internal space of the detector 1 for detecting particles, which are combustion products generated in a fire. This space is covered and shielded from light by, for example, the labyrinth (not shown) of the detector 1. Particles can enter and exit this detection space 101 from the space outside the detector 1, but a known configuration can be applied to the specific structure, so its explanation will be omitted. Details of each element of the detection unit 12 will be described later.

[0041] (Composition - Record Section) The recording unit 13 in Figure 1 is a recording means for recording the program and various data necessary for the operation of the sensor 1. The recording unit 13 can be configured using, for example, flash memory.

[0042] (Configuration - Control Unit) The control unit 14 in Figure 1 is a control means for controlling the sensor 1, and specifically, it is a computer comprising a CPU, various programs interpreted and executed on the CPU (including basic control programs such as an OS, and application programs launched on the OS to realize specific functions), and internal memory such as RAM for storing programs and various data. In particular, the control program according to this embodiment is installed on the sensor 1 via any recording medium or network, and substantially constitutes each part of the control unit 14.

[0043] Functionally, this control unit 14 includes a processing unit 141. The processing unit 141 is a processing unit that detects particles and / or determines whether the particles are monodisperse particles having a particle size within a predetermined particle size range smaller than the wavelength of the first emitted light, based on the reception result of the first scattered light by the first light receiving unit. The processing performed by each part of this control unit 14 will be described later.

[0044] (Configuration - Details of each element in the detection unit) Next, we will describe the details of each element of the detection unit 12.

[0045] ===Scattered surface=== The first scattering plane 911 in Figure 2 represents a plane defined by the optical axis 121a of the light-emitting element 121 and the optical axis 122a of the first photodetector 122, that is, a plane containing two straight lines corresponding to each optical axis. The second scattering plane 912 in Figure 2 represents a plane defined by the optical axis 121a of the light-emitting element 121 and the optical axis 123a of the second photodetector 123, that is, a plane containing two straight lines corresponding to each optical axis.

[0046] In this embodiment, the example shows a case where each scattering surface is a different plane that intersects with each other. However, the system is not limited to this, and each element may be arranged so that a single common scattering surface is provided by placing each element so that each optical axis of each element is contained within a single common plane (the same applies to other embodiments).

[0047] ===Planes of Polarization=== Each polarization plane 121b, 122b, and 123b, shown on each optical axis of each element, represents the polarization plane of the light emitted (i.e., output) or received by each element.

[0048] ===Each element=== Each element of the detection unit 12 is arranged such that the optical axes 121a, 122a, and 123a of each element intersect at the detection point P91. The "detection point" P91 is the point corresponding to the position where a particle is detected, and the particle at this detection point P91 will be detected. Further details of the arrangement of each element will be described later.

[0049] ===Episodic=== The light-emitting element 121 is a first light-emitting unit that emits light to the detection point P91 in the detection space 101. Specifically, it is a component that emits plane-polarized light having a polarization plane 121b parallel to the first scattering plane 911. The specific configuration of the light-emitting element 121 is arbitrary, but it can be constructed using, for example, a light-emitting diode and a polarizer. The light emitted from the light-emitting element 121 is also called the "first emitted light." The wavelength of the light emitted by the light-emitting element 121 will be described later.

[0050] ===First light-receiving element=== The first light-receiving element 122 is a first light-receiving unit that receives scattered light generated when the first emitted light is scattered by particles at the detection point P91 in the detection space 101. Specifically, the first light-receiving element 122 is a component that receives plane-polarized light having a polarization plane 122b parallel to the first scattering plane 911, which is the scattered light generated when the first emitted light is scattered by particles at the detection point P91 in the detection space 101, and which has a scattering angle of 90 degrees relative to the first emitted light. The specific configuration of the first light-receiving element 122 is arbitrary, but for example, it can be configured using a photodiode and a polarizing plate. The scattered light received by the first light-receiving element 122 is also called the "first scattered light".

[0051] Furthermore, "planar polarized light with a scattering angle of 90 degrees" is a concept that refers to planar polarized light received when the scattering angle A11 formed by the optical axis 121a of the light-emitting element 121 and the optical axis 122a of the first light-receiving element 122 is 90 degrees, as shown in Figure 2.

[0052] ===Second photodetector=== The second light-receiving element 123 is a second light-receiving unit that receives scattered light different from the first scattered light. The second light-receiving element 123 is a component that receives plane-polarized light having a polarization plane 123b parallel to the second scattering plane 912, which is the scattered light generated when the first emitted light is scattered by particles at the detection point P91 in the detection space 101, and which has a scattering plane polarized light in the direction of an acute angle of scattering angle with respect to the first emitted light. The specific configuration of the second light-receiving element 123 is arbitrary, but it can be configured using, for example, a photodiode and a polarizing plate. The scattered light received by the second light-receiving element 123 is also called the "second scattered light".

[0053] Furthermore, "planar polarized light in the direction of an acute scattering angle" is a concept that refers to planar polarized light received when the scattering angle A12 formed by the optical axis 121a of the light-emitting element 121 and the optical axis 123a of the second light-receiving element 123 is an acute angle (i.e., an angle smaller than 90 degrees, for example 30 degrees), as shown in Figure 2.

[0054] ===Scattered=== Figure 3 is an explanatory diagram of light scattering by particles. Figure 3(a) shows the intensity of scattered light in each scattering angle direction in Rayleigh scattering, which occurs when light is scattered by particles with a particle diameter smaller than the wavelength of light, and Figure 3(b) shows the intensity of scattered light in each scattering angle direction in Mie scattering, which occurs when light is scattered by particles with a particle diameter larger than the wavelength of light. Figure 3(a) illustrates information about Rayleigh scattering that occurs when, for example, the particle diameter is about one-tenth or less of the wavelength of light (i.e., the wavelength of light is about 10 times or more the particle diameter), and the particle diameter is sufficiently small compared to the wavelength of light.

[0055] <Rayleigh scattering> Figure 3(a) shows, as indicated by the arrows, the intensity of light emitted from the left of the drawing toward point P810 scattered by particles located at point P810, as shown by curves 811 and 812.

[0056] Curve 811 shows the intensity of plane-polarized light having a polarization plane parallel to the scattering plane determined by the optical axis of the light-emitting side and the optical axis of the light-receiving side, and the scattered light that is scattered by particles, specifically the plane-polarized light having a polarization plane parallel to the aforementioned scattering plane (hereinafter also referred to as "parallel scattered light"). In particular, the intensity of scattered light in each scattering angle direction is shown by the distance between the position corresponding to each scattering angle direction on curve 811 and point P810.

[0057] Figure 3(a) shows, for example, that the intensity of parallel scattered light in the angular direction corresponding to scattering angle B11 corresponds to the intensity corresponding to the distance between points P810 and P811. Furthermore, in the direction of a 90-degree scattering angle (vertical axis in the figure), curve 811 almost coincides with point P810, indicating that the intensity of parallel scattered light is approximately 0 (zero).

[0058] Curve 812 shows the intensity of plane-polarized light having a polarization plane parallel to the scattering plane determined by the optical axis of the light-emitting side and the optical axis of the light-receiving side, and the scattered light that is scattered by particles, specifically the plane-polarized light having a polarization plane perpendicular to the aforementioned scattering plane (hereinafter also referred to as "perpendicular scattered light"). In particular, the intensity of scattered light in each scattering angle direction is shown by the distance between the position corresponding to each scattering angle direction on curve 812 and point P810.

[0059] Figure 3(a) shows, for example, that the intensity of the perpendicular scattered light in the angular direction corresponding to scattering angle B11 corresponds to the intensity corresponding to the distance between points P810 and P812, that is, it is greater than the intensity of the parallel scattered light mentioned above. It also shows that the intensity of the perpendicular scattered light in the direction of a scattering angle of 90 degrees corresponds to the intensity corresponding to the distance between points P810 and P813, that is, it is significantly greater than the intensity of the parallel scattered light mentioned above.

[0060] Note that in Figure 3(a), only the intensities of horizontal and vertical scattered light are shown, but the intensities of scattered light at other angles will be represented as curves between curve 811 and curve 812.

[0061] <Mie scattering> Figure 3(b) shows, as indicated by the arrow, the intensity of light emitted from the left of the drawing toward point P820, scattered by a particle located at point P820, as illustrated by curve 821. Curve 821 shows the intensity of scattered light when parallel plane-polarized light is emitted with respect to a scattering plane determined by the optical axis of the light-emitting side and the optical axis of the light-receiving side, and the emitted plane-polarized light is scattered by the particle.

[0062] Figure 3(b) shows, for example, that the intensity of scattered light in the angular direction corresponding to scattering angle B12 corresponds to the intensity corresponding to the distance between points P820 and P821. It also shows that the intensity of scattered light in the direction of a 90-degree scattering angle corresponds to the intensity corresponding to the distance between points P820 and P822, which is significantly greater than the intensity of parallel scattered light in Rayleigh scattering shown by curve 811 in Figure 3(a).

[0063] In Mie scattering, the intensity of plane-polarized light at any angle to the scattering plane is represented by a curve similar in shape to curve 821. In other words, unlike Rayleigh scattering, the intensity of scattered light never becomes nearly zero depending on the scattering angle direction.

[0064] ===Wavelength of light and arrangement of each element=== <particle> In this embodiment, the particles that flow into the detection space 101 of the sensor 1 are assumed to be water particles contained in the smoke (particle size of approximately 0.01 μm to 10 μm), carbon particles contained in the combustion smoke (particle size of approximately 0.001 μm to several μm), and particles corresponding to the combustion products of semiconductor manufacturing gases (silicon dioxide (SiO2) particles) (particle size of approximately 0.05 μm (50 nm) to 0.06 μm (60 nm)).

[0065] Furthermore, noting that silicon dioxide particles are monodisperse particles and fall within a relatively small particle size range, while water particles and carbon particles are not monodisperse particles and exhibit relatively large variations in particle size, we will utilize the characteristic that curve 811 in Rayleigh scattering in Figure 3(a) shows an intensity of scattered light that is almost 0 (zero) in the direction of a scattering angle of 90 degrees to determine whether or not each particle is a silicon dioxide particle, and set the wavelength of light and the arrangement of each element as follows.

[0066] <Wavelength of light> The light-emitting element 121 in Figure 2 is configured to output light with a wavelength of, for example, 900 nm, which is 10 times or more the particle size of the silicon dioxide particles to be judged, as the first emitted light.

[0067] With this configuration, when light emitted by the light-emitting element 121 is irradiated onto silicon dioxide particles, the particle size of the particles is approximately one-tenth or less of the wavelength of the emitted light. Therefore, Rayleigh scattering, one of the Rayleigh scattering or Mie scattering methods, occurs, and the intensity of the scattered light exhibits the characteristics shown in Figure 3(a).

[0068] Furthermore, when the light emitted by the light-emitting element 121 irradiates water particles or carbon particles, the particle diameter of each particle ranges from less than or equal to the wavelength of the emitted light to greater than or equal to that wavelength. Therefore, both Rayleigh scattering and Mie scattering occur, and the intensity of the scattered light exhibits characteristics that combine the properties illustrated in Figures 3(a) and 3(b).

[0069] <Arrangement of each element> The light-emitting element 121 and the first light-receiving element 122 in Figure 2 are positioned so that the scattering angle A11 in Figure 2 is 90 degrees, in order to take advantage of the characteristic that the curve 811 in Figure 3(a) shows an intensity of scattered light that is almost 0 (zero) in the scattering angle direction of 90 degrees, with respect to the silicon dioxide particles to be judged. The second light-receiving element 123 is positioned so that the scattering angle A12 in Figure 2 is acute (for example, 30 degrees).

[0070] (process) Next, we will explain the fire prevention process performed by the detector 1 configured in this way. Figure 4 is a flowchart of the fire prevention process. The fire prevention process is the process of taking measures to prevent fires occurring in the target area. The timing of the execution of this fire prevention process is arbitrary, but for example, we will assume that it is repeatedly executed after the power of detector 1 is turned on, and we will explain it from the point when the process is started.

[0071] ===SA1=== In SA1 in Figure 4, the processing unit 141 determines whether or not a fire has occurred. Specifically, although arbitrary, for example, the determination is made based on scattered light received via the second photodetector 123 after light is emitted from the light-emitting element 121 in Figure 2.

[0072] In detail, the presence detection threshold is stored in the recording unit 13. The "presence detection threshold" is a threshold for detecting the presence of particles (the aforementioned water particles, carbon particles, or silicon dioxide particles) in the detection space 101, and for example, the specific value may be determined by experimentation or simulation.

[0073] In detail, the process is as follows: If the light intensity value on the second light-receiving element side, which indicates the intensity of scattered light received by the second light-receiving element 123, is below the threshold for determining presence, the presence of particles is not detected, and it is determined that no fire has occurred in the target area (SA1 NO). SA1 is then repeatedly executed until it is determined that a fire has occurred. If the light intensity value on the second light-receiving element side is greater than the threshold for determining presence, the presence of particles is detected, and it is determined that a fire has occurred in the target area (SA1 YES), and the process proceeds to SA2.

[0074] <If no fire has occurred> Here, for example, if no fire is occurring in the target area, no particles will flow into the detection space 101. Therefore, when light is emitted from the light-emitting element 121, no scattered light will be generated in the detection space 101, and the second light-receiving element 123 will not receive any scattered light. In this case, the light-receiving intensity value on the second light-receiving element side will be 0 (zero), and since the light-receiving intensity value on the second light-receiving element side is below the threshold for presence determination, the presence of particles is not detected, and it is determined that no fire is occurring in the target area.

[0075] <In the event of a smuggling fire or combustion fire> Furthermore, for example, if a smoldering fire or combustion fire occurs in the target area, and water particles contained in the smoke generated by the fire or carbon particles contained in the combustion smoke flow into the detection space 101, at detection point P91 in Figure 2, the light emitted by the light-emitting element 121 is scattered by the water particles or carbon particles, generating scattered light, which the second light-receiving element 123 receives. In this case, the light-receiving intensity value on the second light-receiving element side becomes greater than the threshold for presence determination, so the presence of particles is detected, and it is determined that a fire has occurred in the target area.

[0076] <In the event of a fire involving gases used in semiconductor manufacturing> Furthermore, for example, if a fire involving semiconductor manufacturing gas occurs in the target area, and silicon dioxide particles, which are combustion products of the semiconductor manufacturing gas generated by the fire, flow into the detection space 101, then at detection point P91 in Figure 2, the light emitted by the light-emitting element 121 is scattered by the silicon dioxide, generating scattered light, which the second light-receiving element 123 receives. In this case, the light-receiving intensity value on the second light-receiving element side becomes greater than the threshold value for presence determination, so the presence of particles is detected, and it is determined that a fire has occurred in the target area.

[0077] In particular, since the scattering angle A12 in Figure 2 is set to an acute angle, and the second photodetector 123 is configured to receive scattered light different from the first scattered light mentioned above, silicon dioxide particles can also be reliably detected based on the light received by the second photodetector 123.

[0078] ===SA2=== In SA2 in Figure 4, the processing unit 141 determines the type of fire. Specifically, although arbitrary, the determination is made based on the scattered light received via the first photodetector 122 when light is emitted from the light-emitting element 121 in SA1.

[0079] In detail, the type determination threshold is stored in the recording unit 13. The "type determination threshold" is a threshold used to determine whether or not the particles in the detection space 101 are silicon dioxide particles, and for example, a specific value may be determined by experiment or simulation. Regarding this type determination threshold, with respect to silicon dioxide particles, the curve 811 in Figure 3(a) shows an intensity of scattered light that is almost 0 (zero) in the scattering angle direction of 90 degrees, and it may be set to a value that is lower than the aforementioned presence determination threshold and slightly greater than 0 (zero).

[0080] In detail, the processing is as follows: If the light intensity value on the first light-receiving element side, which indicates the intensity of scattered light received by the first light-receiving element 122, is below the threshold for type determination, the particles detected by SA1 are determined to be silicon dioxide particles, and the type of fire is determined to be a semiconductor manufacturing gas fire. If the light intensity value on the first light-receiving element side is greater than the threshold for type determination, the particles detected by SA1 are determined not to be silicon dioxide particles (i.e., the particles detected by SA1 are determined to be water particles or carbon particles), and the type of fire is determined to be a smoldering fire or a combustion fire.

[0081] <In the event of a smuggling fire or combustion fire> For example, if a smoldering fire or combustion fire occurs in the target area, and water particles contained in the smoldering smoke or carbon particles contained in the combustion smoke flow into the detection space 101, then multiple water particles or multiple carbon particles will be placed at the detection point P91 in Figure 2. As mentioned above, there is a relatively large variation in the particle size of these particles, so when light emitted from the light-emitting element 121 irradiates these particles at the detection point P91, both Rayleigh scattering and Mie scattering occur, and the first photodetector 122 receives the scattered light resulting from this scattering. Therefore, the light-receiving intensity value on the first photodetector side becomes larger than the threshold for type determination, so the particles detected by SA1 are determined not to be silicon dioxide particles (i.e., the particles detected by SA1 are determined to be water particles or carbon particles), and the type of fire is determined to be a smoldering fire or a combustion fire.

[0082] Furthermore, the system may be configured to further determine whether the fire is a smoldering fire or a combustion fire. For example, the system may be configured to determine the difference between the light intensity value on the first light-receiving element side when scattered by water particles and the light intensity value on the first light-receiving element side when scattered by carbon particles by conducting experiments or simulations in advance, and to make a determination based on the results of such determination. Specifically, for example, a threshold for determining other types (a threshold for determining whether it is a water particle or a carbon particle) may be set, and if the light intensity value on the first light-receiving element side is less than or equal to the threshold for determining other types, it may be determined to be a carbon particle and the fire type may be determined to be a combustion fire. If the light intensity value on the first light-receiving element side is greater than the threshold for determining other types, it may be determined to be a water particle and the fire type may be determined to be a smoldering fire.

[0083] <In the event of a fire involving gases used in semiconductor manufacturing> Furthermore, for example, if a fire involving semiconductor manufacturing gas occurs in the target area, and silicon dioxide particles, which are combustion products of the semiconductor manufacturing gas generated by the fire, flow into the detection space 101, then multiple silicon dioxide particles will be present at the detection point P91 in Figure 2. As mentioned above, the particle sizes of these particles are relatively uniform and are less than or equal to about one-tenth of the wavelength of light from the light-emitting element 121. Therefore, when light emitted from the light-emitting element 121 irradiates these particles at the detection point P91, Rayleigh scattering occurs. In this case, the intensity of the scattered light due to this scattering is the intensity shown by curve 811 in Figure 3(a), and the intensity is almost 0 (zero) in the direction of a scattering angle of 90 degrees, which corresponds to the first photodetector 122. Therefore, since the light-receiving intensity value on the first photodetector side is below the threshold for type determination, the particles detected by SA1 are determined to be silicon dioxide particles, and the type of fire is determined to be a semiconductor manufacturing gas fire.

[0084] ===SA3=== In SA3 of Figure 4, the processing unit 141 outputs various information related to the fire based on the processing results of SA1 and SA2. Specifically, although optional, for example, it transmits information indicating that a fire has occurred and information indicating the type of particles or fire determined in SA2 to an external device (e.g., a disaster prevention receiver or a server device at the disaster prevention center) via the communication unit 21. By outputting various information related to the fire in this way, it becomes possible to carry out appropriate firefighting activities according to the type of fire that has occurred. This completes the disaster prevention processing.

[0085] (Effects of the embodiment) Thus, according to this embodiment, by detecting particles and / or determining whether the particles are monodisperse particles (for example, silicon dioxide particles in this embodiment) having a particle size within a predetermined particle size range smaller than the wavelength of the first emitted light (for example, in this embodiment, approximately 50 nm or more to approximately 60 nm or less), it becomes possible to appropriately identify particles.

[0086] Furthermore, when the presence of particles is detected based on the reception result of the second scattered light by the second photodetector 123, it is possible to appropriately detect and identify particles using, for example, two types of scattered light by determining whether the particles are monodisperse particles (in this embodiment, for example, silicon dioxide) based on the reception result of the first scattered light by the first photodetector 122.

[0087] (Embodiment 2) Next, Embodiment 2 will be described. In this embodiment, the case in which the sensor comprises two light-emitting elements and one light-receiving element will be described. In Embodiment 2, only the characteristic configuration of this embodiment will be described, and the configuration that is the same as the configuration described in Embodiment 1 will not be described. In addition, unless otherwise specified, each element of Embodiment 2 is the same as the element with the same name in Embodiment 1.

[0088] (composition) First, the configuration of the sensor according to this embodiment will be described. Figure 5 is a block diagram showing the sensor according to this embodiment, and Figure 6 is a diagram showing each element of the sensor.

[0089] The detector 2 in Figure 1 is the aforementioned particle detector, specifically a device for detecting fires occurring in a target area, and comprises, for example, a communication unit 21, a detection unit 22, a recording unit 23, and a control unit 24.

[0090] (Composition - Communications Department) The communication unit 21 in Figure 5 is a communication means for communicating with external devices (for example, a disaster prevention receiver).

[0091] (Configuration - Detection Unit) The detection unit 22 in Figure 5 is a component for detecting a fire in the target area, and includes, for example, a first light-emitting element 221, a second light-emitting element 222, and a light-receiving element 223. The first light-emitting element 221, the second light-emitting element 222, and the light-receiving element 223 are also collectively referred to as "each element."

[0092] Each element of the detection unit 22 is located within the detection space 102 of the sensor 2, as shown in Figure 6. Details will be described later.

[0093] (Composition - Record Section) The recording unit 23 in Figure 5 is a recording means for recording the program and various data necessary for the operation of the sensor 2.

[0094] (Configuration - Control Unit) The control unit 24 in Figure 5 is a control means for controlling the sensor 2, and functionally, it includes a processing unit 241. The processing unit 241 is a processing unit that detects particles and / or determines whether the particles are monodisperse particles having a particle size within a predetermined particle size range smaller than the wavelength of the first emitted light, based on the light reception result of the first scattered light by the first light receiving unit. The processing performed by each part of this control unit 24 will be described later.

[0095] (Configuration - Details of each element in the detection unit) Next, we will describe the details of each element in the detection unit 22.

[0096] ===Scattered surface=== The first scattering plane 921 in Figure 6 is a plane defined by the optical axis 221a of the first light-emitting element 221 and the optical axis 223a of the photodetector 223. The second scattering plane 922 in Figure 6 is a plane defined by the optical axis 222a of the second light-emitting element 222 and the optical axis 223a of the photodetector 223.

[0097] ===Each element=== Each element of the detection unit 22 is arranged such that the optical axes 221a, 222a, and 223a of each element intersect at the detection point P92. Details of the arrangement of each element will be described later.

[0098] ===First Light-Emitting Device=== The first light-emitting element 221 is a first light-emitting unit that emits light to the detection point P92 in the detection space 102. Specifically, it is a component that emits plane-polarized light having a polarization plane 221b parallel to the first scattering plane 921. The light emitted from the first light-emitting element 221 is also referred to as the "first emitted light." The wavelength of the light emitted by the first light-emitting element 221 will be described later.

[0099] ===Second photodetector=== The second light-emitting element 222 is a second light-emitting unit that emits light different from the first emitted light to the detection point P92 in the detection space 102. The second light-emitting element 222 is, for example, a component that emits plane-polarized light having a polarization plane 222b parallel to the second scattering plane 922. The light emitted from the second light-emitting element 222 is also referred to as the "second emitted light". The wavelength of the light emitted by the second light-emitting element 222 may be the same as or different from the wavelength of the light emitted by the first light-emitting element 221.

[0100] ===Light-receiving element=== The light-receiving element 223 is a first light-receiving unit that receives scattered light generated when the first emitted light is scattered by particles at detection point P92 in the detection space 102. Specifically, the light-receiving element 223 is a component that receives plane-polarized light having a polarization plane 223b parallel to the first scattering plane 921, which is the scattered light generated when the first emitted light is scattered by particles at detection point P92 in the detection space 102, and which has a scattering angle of 90 degrees relative to the first emitted light. The light-receiving element 223 is also a second light-receiving unit that receives scattered light generated when the second emitted light is scattered by particles at detection point P92 in the detection space 102. The scattered light generated based on the first emitted light among the scattered light received by the light-receiving element 223 is also called the "first scattered light". The scattered light generated based on the second emitted light among the scattered light received by the light-receiving element 223 is also called the "second scattered light".

[0101] <Wavelength of light> The first light-emitting element 221 in Figure 6 is configured to output light with a wavelength of, for example, 900 nm, which is 10 times or more the particle size of the silicon dioxide particles to be judged. The wavelength of the light emitted by the second light-emitting element 222 is arbitrary, but for example, it is set to be the same wavelength as the light emitted by the first light-emitting element 221.

[0102] <Arrangement of each element> Regarding the first light-emitting element 221 and the photodetector 223 in Figure 6, they are positioned so that the scattering angle A21 formed by the optical axis 221a of the first light-emitting element 221 and the optical axis 223a of the photodetector 223 in Figure 6 is 90 degrees, so that the characteristic of the silicon dioxide particles to be judged, shown by curve 811 in Figure 3(a), which shows an intensity of scattered light that is almost 0 (zero) in the direction of a scattering angle of 90 degrees, can be utilized. Furthermore, regarding the second light-emitting element 222, they are positioned so that the scattering angle A22 formed by the optical axis 222a of the second light-emitting element 222 and the optical axis 223a of the photodetector 223 in Figure 6 is acute (for example, 30 degrees).

[0103] (process) Next, we will explain the disaster prevention process performed by the detector 2 configured in this way.

[0104] ===SB1=== In SB1 in Figure 4, the processing unit 241 determines whether or not a fire has occurred. Specifically, although arbitrary, for example, the determination is made based on the scattered light received by the light-receiving element 223 after emitting light from the second light-emitting element 222 in Figure 6. In this case, the first light-emitting element 221 does not emit light.

[0105] This is basically the same as SA1 in Embodiment 1. If the light intensity value on the second light-emitting element side, which indicates the intensity of scattered light received by the photodetector 223 based on light from the second light-emitting element 222, is below the threshold for presence determination, the presence of particles is not detected, and it is determined that no fire has occurred in the target area (NO in SB1). SB1 is then repeatedly executed until it is determined that a fire has occurred. If the light intensity value on the second light-emitting element side is greater than the threshold for presence determination, the presence of particles is detected, and it is determined that a fire has occurred in the target area (YES in SB1), and the process proceeds to SB2.

[0106] ===SB2=== In SB2 of Figure 4, the processing unit 241 determines the type of fire. Specifically, although arbitrary, for example, the determination is made based on the scattered light received by the first light-emitting element 221 in Figure 6 via the light-receiving element 223. In this case, the second light-emitting element 222 does not emit light.

[0107] Basically, this is the same as SA2 in Embodiment 1. If the light intensity value on the first light-emitting element side, which indicates the intensity of scattered light received by the photodetector 223 based on light from the first light-emitting element 221, is less than or equal to the threshold for type determination, the particles detected by SB1 are determined to be silicon dioxide particles, and the type of fire is determined to be a semiconductor manufacturing gas fire. If the light intensity value on the first light-emitting element side is greater than the threshold for type determination, the particles detected by SB1 are determined not to be silicon dioxide particles (i.e., the particles detected by SB1 are determined to be water particles or carbon particles), and the type of fire is determined to be a smoldering fire or a combustion fire.

[0108] In addition, the system may be configured to further determine whether the type of fire is a smoldering fire or a combustion fire, similar to the method described in Embodiment 1.

[0109] ===SB3=== In SB3 of Figure 4, the processing unit 241 outputs various information related to the fire based on the processing results of SB1 and SB2. Specifically, although it is arbitrary, it performs processing similar to SA3 in Embodiment 1. This completes the fire prevention processing.

[0110] (Effects of the embodiment) Thus, according to this embodiment, by detecting particles and / or determining whether the particles are monodisperse particles (for example, silicon dioxide particles in this embodiment) having a particle size within a predetermined particle size range smaller than the wavelength of the first emitted light (for example, in this embodiment, approximately 50 nm or more to approximately 60 nm or less), it becomes possible to appropriately identify particles.

[0111] Furthermore, when the presence of particles is detected based on the reception result of the second scattered light by the photodetector 223, it is possible to determine whether or not the particles are monodisperse particles based on the reception result of the first scattered light by the photodetector 223, thereby enabling appropriate detection and identification of particles using, for example, two types of scattered light. Additionally, by providing, for example, a second light-emitting element 222 that emits a second emitted light different from the first emitted light into the detection space 102, it is possible to emit a second emitted light suitable for particle detection, thereby enabling reliable detection of particles.

[0112] [Modifications of the embodiment] While embodiments of the present invention have been described above, the specific configurations and means of the present invention can be arbitrarily modified and improved within the scope of the technical idea of ​​each invention described in the claims. Such modifications will be described below.

[0113] (Regarding the problems to be solved and the effects of the invention) First, the problems that the invention aims to solve and the effects of the invention are not limited to those described above, and may vary depending on the implementation environment and details of the invention's configuration. In some cases, only a portion of the problems described above may be solved, or only a portion of the effects described above may be achieved.

[0114] (Regarding decentralization and integration) Furthermore, the above-described configuration is a functional concept and does not necessarily require that the physical configuration be as shown in the illustration. In other words, the specific forms of distribution and integration of each part are not limited to those shown in the illustration, and all or part of them can be functionally or physically distributed or integrated in any unit. Also, the term "device" in this application is not limited to a single device, but includes devices composed of multiple devices.

[0115] (Regarding the scattering angle) Furthermore, while Figure 2 describes the case where the scattering angle A12 formed by the optical axis 121a of the light-emitting element 121 and the optical axis 123a of the second light-receiving element 123 is set to an acute angle (i.e., an angle smaller than 90 degrees), it is not limited to this case. The scattering angle A12 may also be set to an obtuse angle (i.e., an angle larger than 90 degrees). Similarly, the scattering angle A22 in Figure 6 may also be set to an obtuse angle.

[0116] (Regarding the determination of particle types) Furthermore, while Figure 4's SA2 describes a case where the light intensity value on the first photodetector side and the type determination threshold are compared to determine whether the detected particle is a silicon dioxide particle or not, the system is not limited to this. For example, the system may be configured to perform a division of the light intensity value on the second photodetector side by the light intensity value on the first photodetector side and make a determination based on the division result. More specifically, if the detected particle is a silicon dioxide particle, the light intensity value on the first photodetector side will be approximately 0 (zero), resulting in an extremely large number for the division or making division impossible. However, if the detected particle is not a silicon dioxide particle, the light intensity value on the first photodetector side will be relatively large (for example, about twice or three times the light intensity value on the second photodetector side). The system may be configured to make a determination based on a comparison between the division result and the threshold, or whether division is possible or not.

[0117] Furthermore, the determination of whether a particle is a water particle or a carbon particle may also be configured to be based on a comparison between the division result and the threshold value.

[0118] (Regarding the light-receiving part) Embodiment 2 describes a case where one light-receiving element is provided, but it is not limited to this. For example, in addition to the first light-receiving element that receives the first scattered light (for example, the light-receiving element 223 in Figure 6), a second light-receiving element that receives the second scattered light may be provided, and the presence of particles may be detected based on the light-receiving result of the second light-receiving element, and it may be determined whether or not the detected particles are silicon dioxide particles based on the light-receiving result of the first light-receiving element. In this configuration, the first light-receiving element may be interpreted as corresponding to the "first light-receiving unit," and the second light-receiving element may be interpreted as corresponding to the "second light-receiving unit."

[0119] (Regarding the plane of polarization and the plane of scattering) Furthermore, in Embodiment 1, the second light-receiving element 123 in Figure 2 was described as being configured to receive plane-polarized light having a polarization plane 123b parallel to the second scattering plane 912, which is scattered light generated when the first emitted light is scattered by particles at the detection point P91 in the detection space 101, and is in the direction of a sharp scattering angle with respect to the first emitted light. However, the invention is not limited to this, and the polarization plane of the scattered light that can be received may be arbitrarily changed.

[0120] For example, the second light-receiving element 123 in Figure 2 may be configured to receive plane-polarized light having a polarization plane perpendicular to the second scattering surface 912, which is the scattered light generated when the first emitted light is scattered by the particles at the detection point P91 in the detection space 101, and to receive plane-polarized light in the direction of the acute scattering angle with respect to the first emitted light. With this configuration, for example, with respect to silicon dioxide particles, the intensity value of the scattered light received by the second light-receiving element 123 can be increased to approach the intensity value shown by the curve 812 in Figure 3(a), thereby enabling reliable detection of the particles.

[0121] Furthermore, while Embodiment 2 described a case in which the second light-emitting element 222 in Figure 6 is configured to emit plane-polarized light having a polarization plane 221b parallel to the second scattering plane 922, the embodiment is not limited to this, and the polarization plane of the emitted light may be arbitrarily polarized.

[0122] For example, the second light-emitting element 222 in Figure 6 may be configured to emit plane-polarized light having a polarization plane perpendicular to the second scattering plane 922. In this configuration, for example, with respect to silicon dioxide particles, the intensity value of the scattered light received by the photodetector 223 can be increased to approach the intensity value shown by the curve 812 in Figure 3(a), thereby enabling reliable detection of the particles.

[0123] (Regarding application) Furthermore, although the above embodiment describes the case in which the particle detector is applied to detectors 1 and 2, it is not limited to this and may be applied to other devices. For example, the particle detector may be applied to a suction-type smoke detector.

[0124] (Regarding the features) Furthermore, the features of the above embodiments and the features of the modified embodiments may be combined in any way.

[0125] (Regarding the interpretation of terms) Furthermore, in the processing of the above embodiment, "determining" may be interpreted as indicating "identifying".

[0126] (Note) The particle detector described in Appendix 1 is a particle detector for detecting particles in a detection space, comprising: a first light-emitting unit that emits first emitted light into the detection space; a first light-receiving unit that receives first scattered light generated when the first emitted light is scattered by the particles in the detection space; and a processing unit that detects the particles and / or determines whether the particles are monodisperse particles having a particle diameter within a predetermined particle diameter range smaller than the wavelength of the first emitted light, wherein the first light-emitting unit emits polarized light having a polarization plane parallel to the scattering plane determined by the optical axis of the first light-emitting unit and the optical axis of the first light-receiving unit as the first emitted light, and the first light-receiving unit receives polarized light having a polarization plane parallel to the scattering plane among the scattered light generated when the first emitted light is scattered by the particles in the detection space, and polarized light at a scattering angle of 90 degrees with respect to the first emitted light as the first scattered light.

[0127] The particle detector in Appendix 2 is a particle detector described in Appendix 1, further comprising a second light-receiving unit that receives a second scattered light different from the first scattered light, and the processing unit, when it detects the presence of the particle based on the result of receiving the second scattered light by the second light-receiving unit, determines whether the particle is the monodisperse particle based on the result of receiving the first scattered light by the first light-receiving unit.

[0128] The particle detector in Appendix 3 is the particle detector described in Appendix 2, wherein the second light-receiving unit receives polarized light having a polarization plane perpendicular to the scattering plane determined by the optical axis of the first light-emitting unit and the optical axis of the second light-receiving unit as the second scattered light.

[0129] The particle detector in Appendix 4 is a particle detector as described in Appendix 1, comprising: a second light-emitting unit that emits a second light different from the first light into the detection space; and a second light-receiving unit that receives a second scattered light generated when the second light is scattered by the particles in the detection space. The processing unit, when it detects the presence of the particles based on the result of receiving the second scattered light by the second light-receiving unit, determines whether the particles are monodisperse particles based on the result of receiving the first scattered light by the first light-receiving unit.

[0130] The particle detector in Appendix 5 is the particle detector described in Appendix 4, wherein the second light-emitting unit emits polarized light as the second emitted light, having a polarization plane perpendicular to the scattering plane determined by the optical axis of the second light-emitting unit and the optical axis of the second light-receiving unit.

[0131] The particle detector in Appendix 6 is the particle detector described in any one of Appendix 1 to 5, wherein the monodisperse particles are combustion products of semiconductor manufacturing gases.

[0132] (Effect of the note) According to the particle detector described in Appendix 1, it becomes possible to appropriately identify particles by detecting them and / or determining whether the particles are monodisperse particles having a particle diameter within a predetermined particle diameter range smaller than the wavelength of the first emitted light.

[0133] According to the particle detector described in Appendix 2, when the presence of a particle is detected based on the reception result of the second scattered light by the second light receiving unit, it is possible to determine whether or not the particle is a monodisperse particle based on the reception result of the first scattered light by the first light receiving unit, thereby enabling appropriate detection and identification of the particle using, for example, two types of scattered light.

[0134] According to the particle detector described in Appendix 3, by receiving polarized light having a polarization plane perpendicular to the scattering plane determined by the optical axis of the first light-emitting unit and the optical axis of the second light-receiving unit as second scattered light, for example, the intensity of the received second scattered light can be increased, making it possible to reliably detect particles.

[0135] According to the particle detector described in Appendix 4, when the presence of a particle is detected based on the reception result of the second scattered light by the second light receiving unit, it is possible to determine whether or not the particle is a monodisperse particle based on the reception result of the first scattered light by the first light receiving unit, thereby enabling appropriate detection and identification of the particle using, for example, two types of scattered light. Furthermore, by providing, for example, a second light emitting unit that emits a second emitted light different from the first emitted light into the detection space, it is possible to emit a second emitted light suitable for particle detection, thereby enabling reliable detection of the particle.

[0136] According to the particle detector described in Appendix 5, by emitting polarized light having a polarization plane perpendicular to the scattering plane determined by the optical axis of the second light-emitting unit and the optical axis of the second light-receiving unit as the second emitted light, for example, the intensity of the second scattered light based on the second emitted light can be increased, thereby enabling reliable detection of particles.

[0137] According to the particle detector described in Appendix 6, monodisperse particles are combustion products of semiconductor manufacturing gases, making it possible to appropriately identify, for example, combustion products of conductor manufacturing gases. [Explanation of Symbols]

[0138] 1 sensor 2 sensor 11 Communications Department 12 Detection unit 13 Records Section 14 Control Unit 21 Communications Department 22 Detection unit 23 Records Department 24 Control Unit 101 Detection space 102 Detection space 121 Light-emitting element 121a Optical axis 121b Polarization plane 122 First light-receiving element 122a optical axis 122b Polarization plane 123 Second photodetector 123a Optical axis 123b Polarization plane 141 Processing Unit 221 First light-emitting element 221a Optical axis 221b Polarization plane 222 Second light-emitting element 222a optical axis 222b Polarization plane 223 Photodetector 223a optical axis 223b Polarization plane 241 Processing Unit 811 Curve 812 curve 821 Curve 911 1st scattering plane 912 2nd scattering plane 921 1st scattering plane 922 2nd scattering plane A11 1st scattering angle A12 2nd scattering angle A21 1st scattering angle A22 2nd scattering angle B11 Scattering angle B12 Scattering angle P91 detection point P92 detection point P810 points P811 points P812 points P813 points P820 ​​points P821 points P822 points

Claims

1. A particle detector that detects particles in a detection space, A first light-emitting unit that emits a first emitted light into the detection space, A first light receiving unit that receives first scattered light generated when the first emitted light is scattered by the particles in the detection space, The system includes a processing unit that detects the particles and / or determines whether the particles are monodisperse particles having a particle diameter within a predetermined particle diameter range smaller than the wavelength of the first emitted light, based on the light reception result of the first scattered light by the first light receiving unit, The first light-emitting unit emits polarized light having a polarization plane parallel to the scattering plane determined by the optical axis of the first light-emitting unit and the optical axis of the first light-receiving unit as the first emitted light. The first light receiving unit receives as first scattered light polarized light having a polarization plane parallel to the scattering plane, among the scattered light generated when the first emitted light is scattered by the particles in the detection space, and polarized light with a scattering angle of 90 degrees relative to the first emitted light. Particle detector.

2. It comprises a second light-receiving unit that receives a second scattered light different from the first scattered light, When the processing unit detects the presence of the particles based on the light reception result of the second scattered light by the second light receiving unit, it determines whether the particles are monodisperse particles based on the light reception result of the first scattered light by the first light receiving unit. The particle detector according to claim 1.

3. The second light-receiving unit receives polarized light having a polarization plane perpendicular to the scattering plane determined by the optical axis of the first light-emitting unit and the optical axis of the second light-receiving unit as the second scattered light. The particle detector according to claim 2.

4. A second light-emitting unit emits a second light different from the first emitted light into the detection space, The device comprises a second light-receiving unit that receives second scattered light generated when the second emitted light is scattered by the particles in the detection space, When the processing unit detects the presence of the particles based on the light reception result of the second scattered light by the second light receiving unit, it determines whether the particles are monodisperse particles based on the light reception result of the first scattered light by the first light receiving unit. The particle detector according to claim 1.

5. The second light-emitting unit emits polarized light having a polarization plane perpendicular to the scattering plane determined by the optical axis of the second light-emitting unit and the optical axis of the second light-receiving unit as the second emitted light. The particle detector according to claim 4.

6. The monodisperse particles are combustion products of semiconductor manufacturing gases. A particle detector according to any one of claims 1 to 5.

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