JP2019158723A - Particle sensor, electronic apparatus equipped therewith, and particle information detection method - Google Patents

Abstract

To provide a particle sensor that detects particle information such as dust concentration with good accuracy, even when there is occurrence of a noise signal attributable to a use environment or an attached individual apparatus.SOLUTION: The particle sensor comprises: a light emitting element (21) for irradiating a detection area (DA) with light; a light receiving element (23) for receiving scattered light of the light from the light emitting element (21); an air current generation unit (40) for generating a flow of a gas in the detection area (DA); and a signal processing unit (60) for processing time-series signals that indicate outputs from the light receiving element (23) and thereby detecting particle information included in the gas in the detection area (DA). The signal processing unit (60) includes: correction means which, while the air current generation unit (40) is turned off, acquires time-series signals that indicate outputs from the light receiving element (23), processes the acquired signals, and calculates a noise correction value; and measurement means which, while the air current generation unit (40) is up and operating, acquires time-series signals that indicate outputs from the light receiving element (23), corrects the acquired signals for noise using the noise correction value, and detects particle information.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a particle sensor, an electronic apparatus including the particle sensor, and a particle information detection method.

  In recent years, an optical sensor has been proposed as a particle sensor for detecting particles such as fine particles. Such a particle sensor includes a light emitting element and a light receiving element, and is configured to take in a gas containing particles to be measured into the sensor. In other words, the gas taken in is irradiated with light from the light emitting element, the scattered light is received by the light receiving element, and the presence or absence and the amount of particles contained in the gas are detected by the scattered light. The particles to be detected are, for example, dust, pollen, smoke, etc. floating in the atmosphere. An example of such a particle sensor is that described in Patent Document 1.

  As described in Patent Document 2, the analog signal detected by the light receiving element is amplified and output as a time-series voltage signal including a pulse-like waveform. This time-series voltage signal is converted by an AD converter and converted into digital data to calculate the particle concentration and the like.

  Rather than being used as a single unit, the particle sensor is often attached to an electronic device such as an air purifier and used for operation control of the device. Therefore, the particle sensor may be affected by noise generated by the attached device itself. That is, there is so-called background noise in which peripheral members of the particle sensor in a device such as an air purifier emit a noise signal, and the measurement signal of the particle sensor is affected by the noise signal.

  When the particle measurement signal is amplified and A / D converted with such background noise, the result may be different from the actual particle amount, and the control of various devices based on the measurement result is not optimal control. There was a case.

  The background noise is unique to each individual device to which the particle sensor is attached, and cannot be dealt with by performing a certain process on the particle sensor at the time of shipment. In addition, some noise may occur in combination with the environment in which the device is installed (used).

  The particle sensor described in Patent Document 2 performs a process for correcting an error in a measurement waveform when the fan is stopped and when the fan is operating in order to intermittently operate the fan or the like for power saving. The correction which paid attention to the background noise of each individual is not performed.

JP 2017-166935 A JP 2017-142142 A

  Therefore, the present invention has been made in view of the above-described conventional problems, and even if noise signals are generated due to the use environment or the individual electronic device to be attached, the amount of particles, the number per particle diameter, the concentration of dust, etc. It is an object of the present invention to provide a particle sensor that accurately detects particle information, an electronic device including the particle sensor, and a particle information detection method.

  In order to solve the above problems, a particle sensor of the present invention includes a light emitting element that irradiates light to a detection region, a light receiving element that receives light scattered from the light emitting element by particles in the detection region, and a detection region. An air flow generation unit that generates a gas flow, and a signal processing unit that detects particle information contained in the gas in the detection region by performing signal processing on a time-series signal indicating an output from the light receiving element. The signal processing unit includes a time series signal indicating an output from the light receiving element in a state where the airflow generation unit is stopped, and performs signal processing to calculate a noise correction value. A time series signal indicating an output from the light receiving element in a state where the airflow generation unit is driven and a correction unit that performs the measurement, and performs noise correction using the noise correction value to detect the particle information Means Characterized in that it obtain.

  The particle information is the particle diameter of the particles contained in the gas per unit time and the number of particles per particle diameter, and the measuring means calculates the number of particles per unit volume and the particle diameter per unit time. You may calculate the collected dust density | concentration.

  In addition, the electronic apparatus of the present invention includes an output unit that outputs the particle information from the particle sensor.

  The particle information detection method of the present invention includes a light emitting element that irradiates light to a detection region, a light receiving element that receives light scattered from the light emitting element by particles in the detection region, and a gas flow in the detection region. And a signal processing unit for detecting particle information of particles contained in the gas in the detection region by performing signal processing on a time-series signal indicating an output from the light receiving element. A method of measuring particle information using a particle sensor, wherein the airflow generation unit is stopped, the signal processing unit acquires a time-series signal indicating an output from the light receiving element, performs signal processing, and performs noise processing. A correction step for calculating a correction value; and after calculating a noise correction value in the correction step, the airflow generation unit is driven, and the signal processing unit outputs a time-series signal indicating an output from the light receiving element. Get and said no Wherein the noise correction to and a measurement step of detecting the particles information using the correction value.

  In the present invention, a particle sensor that always detects particle information such as the amount of particles, the number for each particle diameter, the concentration of dust, and the like regardless of the use environment or the individual electronic device to be attached, the electronic device including the particle sensor, and the particle An information detection method can be provided.

1 is an external perspective view schematically showing a particle sensor 1 of a first embodiment. 4 is a plan view schematically showing a method for detecting particles inside the case portion 20. FIG. It is a block diagram which shows the electric constitution of the particle sensor of 1st Embodiment. It is a flowchart which shows the flow of the dust concentration calculation process of the particle | grain sensor of 1st Embodiment. It is a flowchart which shows a noise correction process. FIG. 5A is a waveform diagram showing digitized noise data and a correction process using the noise data. FIG. 5A shows the noise data Vm, which is a time-series digital signal, and a noise correction value Vn obtained by leveling the noise data Vm. The waveform (b) shows the waveform of the measurement value Vs and the noise correction value Vn at the time of measuring the particle concentration, and the figure (c) shows the waveform of the corrected measurement value V after the noise correction. . It is a schematic diagram which shows the particle | grain detection method, The figure (a) is a schematic diagram which shows the mechanism of particle | grain detection, The figure (b) is a wave form diagram which shows the corrected measured value V (t) detected. is there. It is an example of the correspondence table which matched the electric current value, the voltage value, and the particle diameter. It is a block diagram which shows the flow of the signal input / output in a particle sensor. It is a conceptual diagram which shows switching with the electric circuit by the side of the noise data acquisition in a particle sensor. It is a fragmentary diagram of a particle sensor circuit diagram.

(First embodiment)
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The same or equivalent components, members, and processes shown in the drawings are denoted by the same reference numerals, and repeated descriptions are omitted as appropriate.

  The particle sensor of the present invention is attached to a device such as an air cleaner, and measures the dust concentration in the environment where the device is installed. For example, it measures particle information such as the concentration of particles such as fine dust, pollen, smoke and PM2.5 in the ambient air, specifically the size of the particles, the unit volume, and the number of each particle per unit time. From the results, the concentration of each particle in the air (dust concentration) is calculated.

  FIG. 1 is an external perspective view schematically showing the particle sensor 1 of the present embodiment. The particle sensor 1 includes an upper surface lid portion 10, a case portion 20, a lower surface lid portion 30, and a blower fan 40 (also simply referred to as “fan”). As shown in FIG. 1, the upper surface lid portion 10 and the lower surface lid portion 30 are assembled to the upper surface and the lower surface of the case portion 20, respectively, and the blower fan 40 is accommodated in the case portion 20. An air inlet 12 and an air outlet 13 are formed on the top surface 11 of the top cover 10, and a part of the blower fan 40 is exposed from the air outlet 13.

  FIG. 2 is a plan view schematically showing a method for detecting particles inside the case portion 20. In the case portion 20, a light emitting element 21, a light projecting lens 22, a light receiving element 23, and a light receiving lens 24 are arranged. The optical axis of the irradiation light L1 irradiated from the light emitting element 21 via the light projecting lens 22 and the optical axis of the incident light L2 received by the light receiving element 23 via the light receiving lens 24 are arranged so as to be substantially orthogonal to each other. Has been. A region where the incident light L2 can reach the light receiving element 23 via the light receiving lens 24 and a region where the irradiation light L1 is irradiated are overlapped with each other to be a detection region DA where particles can be detected.

  A substantially cylindrical outside air flow path 25 is formed directly below the intake port 12 shown in FIG. 1, and outside air taken in from the intake port 12 flows in and is sent to the exhaust port 13 by the blower fan 40. Discharged. The detection area DA is set near the center of the outside air flow path 25. The central axis of the outside air flow path 25 is substantially orthogonal to the optical axis of the irradiation light L1 and the optical axis of the incident light L2.

  In the particle sensor 1, when the blower fan 40 is operated, outside air flows into the outside air passage 25 from the intake port 12, and particles contained in the outside air pass through the detection area DA. The detection area DA is irradiated with the irradiation light L1 from the light emitting element 21, and the irradiation light L1 is scattered by the particles, and a part of the scattered light enters the light receiving element 23 as the incident light L2. In the light receiving element 23, a voltage is generated according to the amount of incident light L2. At this time, the larger the diameter of the particle, the larger the area where the irradiation light L1 is scattered by the particle, and the light quantity of the scattered light and the incident light L2 also increases. Also grows.

  FIG. 3 is a block diagram showing an electrical configuration of the particle sensor of the present embodiment. The particle sensor 1 according to the present embodiment includes a sensor unit 50, a signal processing unit 60, and a power supply unit 70. Based on scattered light from particles located in the detection area DA of the sensor unit 50, the dust concentration in the ambient air Measure.

  The sensor unit 50 mainly serves as a part for detecting particles in the particle sensor 1. In FIG. 3, the light emitting element 21, the light receiving element 23, and the blower fan 40 are schematically illustrated, and the positional relationship is according to FIGS. 1 and 2.

  The sensor unit 50 includes a light emitting unit 51 and a light receiving unit 52. As described above with reference to FIGS. 1 and 2, the light emitting element 21 of the light emitting unit 51 emits light having a predetermined wavelength toward the detection area DA. The light receiving element 23 of the unit 52 receives the light scattered by the particles and converts the received light into an electrical signal. At this time, as the diameter of the particle passing through the detection area DA increases, the amount of light scattered by the particle and incident on the light receiving element 23 increases, and the value of the electric signal generated by the light receiving element 23 increases. And based on this converted electric signal, the size (particle diameter) of the particles is measured.

  FIG. 4 is a flowchart showing the flow of the dust concentration conversion of the particle sensor of the present embodiment.

  The light scattered by the particles in the detection area DA is received by the light receiving element 23 through the light receiving lens 24. The light receiving element 23 performs O / E conversion on the received light and outputs a signal (for example, a current signal) corresponding to the light intensity (S12). The light receiving unit 52 includes a photo IC diode, a photomultiplier tube, or the like, and performs O / E conversion using these to form a current signal, which is sent to the signal processing unit 60.

  In the signal processing unit 60, the I / V conversion unit 61 converts the current signal output from the light receiving unit 52 into a voltage signal, and the amplification unit 62 amplifies the signal to a predetermined band (S13).

  Thereafter, the A / D converter 63 converts the voltage signal, which is an analog signal amplified by the amplifier 62, into a digital signal (A / D conversion), thereby generating digital data (S14). Specifically, the A / D conversion unit 63 samples and quantizes a voltage signal that is an output signal from the light receiving unit 52, and generates time-series digital data.

  Next, using the digital data generated in this way, the calculation unit 64 performs a dust concentration conversion process for calculating the dust concentration from the number of particles for each particle diameter or the like (S15). Details of the calculation of the dust concentration of this embodiment will be described later.

  By the way, in this embodiment, when the signal-processed voltage signal is amplified and then A / D converted to calculate the dust concentration, noise for each device is removed from the input data, that is, noise from the input data. Dust concentration is calculated by applying a noise correction process to correct the minute. Specifically, the following processing is performed.

  FIG. 5 is a flowchart showing the noise correction process. First, in the present embodiment, the light emitting element 21 of the light emitting unit 51 emits light with the blower fan 40 stopped, and emits light toward the detection area DA. The light receiving unit 52 receives the light in the detection area DA, converts it into an electrical signal such as a current value, and obtains noise data (analog signal) (S21). Here, the state in which the blower fan 40 is stopped is a state in which no airflow is generated in the particle sensor 1, so that almost no outside air flows. Therefore, the particles do not enter the detection area DA. It can be said that the electric signal (analog signal) detected by the light receiving unit 52 in this state is a noise signal emitted from a peripheral member or the like in the place where the particle sensor 1 is installed. In other words, this noise signal indicates so-called background noise. The timing of obtaining noise data used for noise correction and switching to the noise correction processing will be described later.

  Next, the acquired noise data (analog signal) is converted into a time-series digital signal by the analog signal processing unit 601 in FIG. 3 and output in the same procedure as described in step 13 to step 14 in FIG. (S22).

  Next, a process for obtaining the noise correction value Vn from the noise data, which is a time-series digital signal acquired in step 22, is performed (S23).

  FIG. 6 is a waveform diagram showing digitized noise data and a correction process using the noise data. FIG. 6A shows noise data Vm which is a time-series digital signal and noise obtained by leveling the noise data Vm. The waveform of the correction value Vn is shown. FIG. 5B shows the waveform of the measurement value Vs and the noise correction value Vn at the time of measuring the dust concentration (particle concentration), and FIG. The waveform of the finished measurement value V is shown.

  As shown in FIG. 6, the noise data Vm, which is a time-series digital signal, has a waveform that changes every moment. Therefore, the values are leveled by a known method to obtain the noise correction value Vn (constant). For example, in this embodiment, the noise data value Vm (t) is obtained every unit time, the average of Vm (t) within a predetermined time is obtained, and the average value is set as the noise correction value Vn.

  Next, the actual sensor measurement value is corrected using the noise correction value Vn. Returning to the flowchart of FIG. 5, in order to measure the actual dust concentration, the blower fan 40 of the particle sensor 1 is driven, the outside air is taken into the particle sensor 1, and the particles are measured by the sensor unit 50 (S24). Then, the analog signal processing unit 601 performs A / D conversion on the measurement value (analog signal) output from the sensor unit 50 (S25).

  Next, in the present embodiment, the measured value (digital data) Vs (t) is not directly converted into the dust concentration, but the noise correction value Vn obtained previously is subtracted as shown in the equation (1) to generate noise. Correction is performed (S26).

V (t) = Vs (t) −Vn (1)
V (t): Corrected measured value (digital data)
Vs (t): measured value (digital data)
Vn: Noise correction value (constant)
Since the noise correction value Vn is smaller than Vs (t) as shown in FIG. 6B, when the noise correction value is subtracted, the voltage value of V (t) is shown in FIG. 6C. Becomes smaller than Vs (t) by the noise correction value Vn, and the SN ratio is improved.

  In this embodiment, the noise correction value Vn is calculated from the noise data Vm that is a digital signal. However, the present invention is not limited to this, and is calculated at the analog signal stage before A / D conversion. Also good. Even in the case of calculating from the analog signal of the voltage value, the analog signal of the voltage value is leveled and the noise correction value Vn (constant) per unit time is calculated. In actual measurement, the noise correction value Vn (constant) may be subtracted from the measurement value (analog signal), and the corrected measurement value may be A / D converted. Alternatively, the noise correction value may be subtracted from the signal before amplification, and the corrected measurement value may be subjected to amplification processing and A / D conversion processing to perform dust concentration calculation processing.

  Next, the calculation unit 64 calculates the dust concentration (S27). FIG. 7 is a schematic diagram showing a particle detection method. FIG. 4A is a schematic diagram showing the mechanism of particle detection, and FIG. 4B is a waveform diagram showing the corrected measured value V (t) detected. The calculation method of the dust concentration (particle concentration) by the calculation unit 64 is roughly performed according to the following flow.

  As described above, the light (outside air) entering the detection area DA of the outside air flow path 25 is irradiated with light from the light emitting section 51, and the light receiving section 52 receives the light reflected by the particles in the detection area DA. Thus, the voltage signal V (t) subjected to the above-described A / D conversion and noise correction processing is output from the signal processing unit 60 by making a predetermined electrical signal. As shown in FIG. 7 (b), the corrected measurement value V (t) has a different voltage value for each particle, and the particle diameter is calculated from the voltage value. Specifically, the particle diameter is obtained from the pulse height in FIG. 7B, and the number of particles is obtained from the number of pulses per unit time.

  FIG. 8 is an example of a correspondence table in which current values, voltage values, and particle diameters are associated with each other. As shown in this table, the voltage value increases as the particle diameter increases. The computing unit 64 counts the number of particles of each particle diameter from the corrected measurement value V (t), for example, based on this correspondence table, and calculates particle information such as the number of each particle diameter per unit region and unit time. To do.

  The corrected measurement value V (t) may be smoothed so as to be suitable for the calculation process. Specifically, the corrected measurement value V (t) is smoothed using a known integration processing method, moving average method, median filter method, or the like. Here, as an example, the measured value V (t) is smoothed by a simple moving average method.

  For example, the average of corrected measurement values V (1) to V (m) for each unit time may be taken at a predetermined time m as shown in Expression (2).

VM (m) = (V (1) + V (2) +... V (m)) / m (Expression (2))
In this way, the smoothed measurement value VM (t) is calculated every predetermined time m.

  The formula (2) given here is an example, and the calculation need not be based on the average of the corrected measurement values for each unit time of the predetermined time m, and V (1), V (2)... V (m ) The calculation may be performed at each sampling time, or may be performed within an arbitrary time range.

  Then, when calculating the number of particles for each particle diameter, the calculation unit 64 plots the smoothed measurement value VM (t), performs a known approximation process such as linear approximation, polynomial approximation, etc. Corresponding to the table, classify according to the particle size, and count the number of particles of each class (each particle size) per unit time.

Then, the dust concentration is calculated from the flow rate of the air flowing into the outside air passage 25 per unit time and the number of particles counted previously, and is output as digital data (S28). For example, the dust concentration for each class (particle diameter)
PM1.0 xμg / m ³
PM2.5 yμg / m ³
PM10 zμg / m ³
It may be calculated in the form of Or convert it to the number density,
PM1.0 x pieces / m ³
PM2.5 y / m ³
PM10 z pieces / m ³
It is good also as a form.

  Next, a mechanism for stopping the blower fan 40 for obtaining noise data will be described. FIG. 9 is a block diagram showing a signal input / output flow in the particle sensor 1. FIG. 10 is a conceptual diagram showing switching with the electric circuit on the noise data acquisition side. FIG. 11 is a partial view of the particle sensor circuit diagram.

  As described above, when measuring the dust concentration, the particle sensor 1 amplifies the output signal (Pout) from the sensor unit 50 by the amplifier (AMP) 62, inputs it to the CPU 602, and calculates the dust concentration by the calculation unit 64 of the CPU 602. calculate.

  On the other hand, when calculating the noise correction value, the circuit is switched as follows. The blower fan 40 of the particle sensor 1 in the present embodiment is controlled by PWM control. Therefore, when the fan is stopped or stopped, the CPU 602 outputs a stop PWM signal.

  When this signal is input to the circuit on the blower fan 40 side, the open collector circuit 81 is selected from the GND terminal, and the blower fan 40 is not driven. In this state, the noise correction value Vn is calculated as described above, and the noise correction value Vn is stored in the storage unit 65. After that, when a fan drive PWM signal is output from the control unit 66 of the CPU 602, the blower fan 40 side selects a closed collector circuit, and actual dust concentration measurement is performed.

  In the present embodiment, the noise data Vm is acquired when the power is turned on (starting up). However, the present invention is not limited to this, and may be performed at the time of manufacturing an electronic device incorporating a particle sensor. In this case, when the particle sensor 1 is mounted on the electronic device, the PWM signal is output from the CPU 602, the open collector circuit 81 is selected, and the noise correction value Vn is calculated. The calculated noise correction value Vn is stored in the storage unit 65 in the CPU 602 and is always corrected using the initially stored correction value Vn at the time of measurement.

  In this way, noise data Vm is acquired and noise correction value Vn is obtained when an electronic device equipped with a particle sensor is manufactured or when a blower fan of the particle sensor is stopped, that is, when the particle sensor is not measuring the dust concentration. calculate.

  In this way, device-specific or environment-specific noise that occurs regardless of outside air is detected in advance, and correction according to the noise can be eliminated, so that measurement errors due to noise can be largely eliminated, and the measurement accuracy of dust concentration is improved. Can be increased. Therefore, it is possible to calculate the particle information such as the number of particles for each particle diameter and the concentration of dust with high accuracy while substantially eliminating the influence of so-called background noise, which depends on the mounted device and the device mounting environment.

DESCRIPTION OF SYMBOLS 1 ... Particle sensor 10 ... Upper surface cover part 11 ... Top surface 12 ... Inlet port 13 ... Exhaust port 20 ... Case part 21 ... Light emitting element 22 ... Light projection lens 23 ... Light receiving element 24 ... Light receiving lens 25 ... Outside air flow path DA ... Detection Area 30 ... bottom cover 40 ... blower fan (airflow generating part)
DESCRIPTION OF SYMBOLS 50 ... Sensor part 51 ... Light emission part 52 ... Light receiving part 60 ... Signal processing part 61 ... I / V conversion part 62 ... Amplification part 63 ... A / D conversion part 64 ... Calculation part (correction means, measurement means)
65 ... Storage unit 66 ... Control unit 601 ... Analog signal processing unit 602 ... CPU (digital signal processing unit)
70 ... Power supply unit 81 ... Open collector circuit

Claims (12)

A light emitting element for irradiating light to the detection region;
A light receiving element that receives scattered light from the light emitting element due to particles in the detection region;
An airflow generator for generating a gas flow in the detection region;
A particle sensor including a signal processing unit that detects particle information contained in the gas in the detection region by performing signal processing on a time-series signal indicating an output from the light receiving element,
The signal processing unit, with the airflow generation unit stopped, acquires a time-series signal indicating an output from the light receiving element, performs signal processing, and a correction unit that calculates a noise correction value;
A measurement unit that acquires a time-series signal indicating an output from the light receiving element in a state in which the air flow generation unit is driven, and performs noise correction using the noise correction value to detect the particle information. A particle sensor. The particle sensor according to claim 1,
The particle sensor detects the particle information from a noise-corrected signal obtained by subtracting the noise correction value from a time-series signal indicating an output from the light receiving element. The particle sensor according to claim 1 or 2,
The particle sensor according to claim 1, wherein the time-series signal indicating the output from the light receiving element acquired by the signal processing unit is an amplified and A / D converted signal. The particle sensor according to any one of claims 1 to 3,
The correction means uses a mean value of voltage values within a predetermined time of the acquired time series signal as a noise correction value,
The particle sensor according to claim 1, wherein the measurement unit subtracts the noise correction value from a voltage signal that is a time-series signal indicating an output from the light receiving element. The particle sensor according to any one of claims 1 to 4,
The particle information is the particle size of particles contained in the gas per unit time and the number of particles for each particle size,
2. The particle sensor according to claim 1, wherein the measuring means calculates a dust concentration in which the number of particles for each particle diameter per unit volume and unit time is collected. The particle sensor according to any one of claims 1 to 5,
The particle sensor, wherein the air flow generation unit includes a fan. A particle sensor according to any one of claims 1 to 6, comprising:
An electronic apparatus comprising an output unit that outputs the particle information from the particle sensor. A light emitting element for irradiating light to the detection region;
A light receiving element that receives scattered light from the light emitting element due to particles in the detection region;
An airflow generator for generating a gas flow in the detection region;
Using a particle sensor including a signal processing unit that detects particle information of particles contained in the gas in the detection region by performing signal processing on a time-series signal indicating an output from the light receiving element, particle information A method of measuring
A correction step of stopping the air flow generation unit, the signal processing unit acquiring and processing the time-series signal indicating the output from the light receiving element, and calculating a noise correction value;
After calculating a noise correction value in the correction step, the airflow generation unit is driven, and the signal processing unit acquires a time-series signal indicating an output from the light receiving element, and uses the noise correction value. And a measuring step for detecting the particle information by performing noise correction. The particle information detection method according to claim 8, wherein
The particle information detection method, wherein the measurement step detects the particle information from a noise corrected signal obtained by subtracting the noise correction value from a time-series signal indicating an output from the light receiving element. In the particle information detection method according to claim 8 or 9,
An amplification step of amplifying a time-series analog signal indicating an output from the light receiving element;
An A / D conversion step for converting the time-series analog signal amplified in the amplification step into a digital signal,
The particle information detection method, wherein the time-series signal acquired by the signal processing unit is a digital signal converted in the A / D conversion step. In the particle information detection method according to any one of claims 8 to 10,
In the correction step, an average value of voltage values within a predetermined time of the acquired time-series signal is set as a noise correction value,
The particle information detecting method, wherein the measuring step subtracts the noise correction value from a voltage signal which is a time-series signal indicating an output from the light receiving element. In the particle information detection method according to any one of claims 8 to 11,
The particle information is the particle size of particles contained in the gas per unit time and the number of particles for each particle size,
The particle measurement method according to claim 1, wherein the measuring step calculates a dust concentration in which the number of particles for each particle diameter per unit volume and unit time is collected.

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