An aerosol particle optical detection device

Abstract

The present application relates to a kind of aerosol particle optical detection device, comprising: light source, for emitting light beam to irradiate into the aerosol particle of detection area;Aerosol flow channel, for the scattered light detection of aerosol particle;Digital micromirror array component, for the deflection modulation and convergence of different annular aperture scattered light;Distributed single-point detector, for receiving the annular aperture scattered light of convergence, and converting optical signal into electrical signal.The present application is a kind of by digital micromirror array and distributed single-point detector aerosol particle light scattering counting detection device, by the angle selection of each micro-mirror in digital micromirror array, the scattered light of different particle size particles is converged into several single-point detectors respectively, can avoid using large area array multi-element photodetector, while improving the collection efficiency of forward scattering light energy, and no need to calibrate F-D curve, so there is no problem of inaccurate particle size detection caused by Mie resonance zone.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aerosol detection, and particularly relates to an aerosol particle optical detection device. BACKGROUND

[0002] When light passes through a non-uniform medium, scattering occurs, which deviates from the straight propagation direction of the light, and is caused by the combined action of absorption, reflection, refraction, transmission and diffraction. The form of scattered light contains information such as the size, shape, structure, composition and concentration of the scattering body. Therefore, the concentration distribution and refractive index of the particle group can be measured by using light scattering technology, and the size distribution of the particle group can also be measured.

[0003] The existing measuring devices are as follows: (1) forward scattering laser particle size analyzer, particle size spectrometer: the laser particle size analyzer is a precision instrument for measuring the size of powder particles based on the scattering principle of light, which integrates laser technology, modern photoelectric technology, electronic technology, precision machinery and computer technology, and has the advantages of fast measurement speed, large dynamic range, simple operation and good repeatability, and is suitable for measuring powder and liquid droplets with wide particle size distribution. It tests the particle size distribution according to the physical phenomenon that particles can cause laser scattering.

[0004] Mie scattering theory shows that when the light beam encounters a particle block, part of the light will scatter, and the propagation direction of the scattered light will form an angle θ with the propagation direction of the main light beam. The size of the θ angle is related to the size of the particle. The larger the particle, the smaller the θ angle of the scattered light; the smaller the particle, the larger the θ angle of the scattered light. That is, small-angle (θ) scattering light is caused by large particles; large-angle (θ1) scattering light is caused by small particles. Further research shows that the intensity of the scattered light represents the number of particles of that size. In this way, by measuring the intensity of the scattered light at different angles, the particle size distribution of the sample can be obtained. In order to measure the light intensity of the scattered light at different angles, optical means is needed to process the scattered light. A converging lens is placed at a suitable position in the light beam, and a set of multi-element photodetectors is placed on the back focal plane of the lens. When scattered light of different angles passes through the converging lens and illuminates the multi-element photodetector, the optical signal will be converted into an electrical signal and the subsequent signal will be processed, and the particle size distribution can be obtained. The multi-element photodetector is generally composed of dozens of concentric circles or sector rings.

[0005] The forward scattering laser particle size analyzer can simultaneously detect multiple aerosol particles, and the laser light source needs to be collimated into parallel light. After the particles scatter, a large-area multi-element photodetector is needed for converging and focusing.

[0006] (2) Forward scattering light particle counting and detection-based laser dust particle counter: there are two forms: one is based on the distribution of forward scattering light spots, different shapes of particles have different distribution of forward scattering light spot patterns, and the shape of the particle is determined by this principle, which also needs an imaging system and a distributed sensor configuration; the other is to converge the forward scattering light energy to a single point detector, and then measure the particle size through the energy of the scattered light. The particles pass through the light-sensitive area along with the airflow, and the lateral scattering light is collected by a curved mirror, and then converges to a photodetector through a series of lens groups. Whenever a particle passes through the light-sensitive area, a light pulse signal will be generated. The larger the particle, the stronger the scattering light, and the stronger the light pulse signal.

[0007] The forward scattering light particle counting and detection-based laser dust particle counter can only detect and count one aerosol particle at a time, and needs to focus the laser to a small size to reduce the probability of overlapping particles and improve the upper limit of the detection concentration. After the scattering of the particles, the single-point detection is used to detect the scattering light intensity after the convergence and focusing, and the size of the particles is determined through the mapping curve (F-D curve) between the scattering light intensity and the particle size. However, the F-D curve cannot guarantee strict monotonicity, and the one-to-one correspondence between the light energy F and the particle size D cannot be guaranteed. The F-D curve has a Mie resonance region, and the particle size detection in the resonance region is not accurate. SUMMARY

[0008] The technical problem to be solved by the present application is to provide an aerosol particle optical detection device.

[0009] The technical solution of the present application to solve the above technical problems is as follows: an aerosol particle optical detection device, comprising:

[0010] a light source for emitting a light beam to irradiate aerosol particles in a detection area;

[0011] an aerosol flow passage for scattering light detection of aerosol particles;

[0012] a digital micromirror array assembly for deflection modulation and convergence of different annular aperture scattering lights;

[0013] a distributed single-point detector for receiving the converged annular aperture scattering light and converting the light signal into an electrical signal.

[0014] The beneficial effects of the present application are: the device for detecting aerosol particle light scattering counting by digital micromirror array and distributed single-point detector can avoid using large array multi-element photodetector, improve the collection efficiency of forward scattering light energy, and does not need to calibrate F-D curve, so there is no problem of inaccurate particle size detection caused by Mie resonance zone; in addition, multiple particles can be detected when entering the particle counter detection area at the same time, thereby improving the upper limit of the detection concentration of the aerosol particle counter.

[0015] On the basis of the above technical solutions, the present application can also be improved as follows.

[0016] Further, the digital micromirror array assembly comprises:

[0017] The digital micromirror array is used for deflection modulation of different annular aperture scattering lights.

[0018] The scattering light focusing and collecting optical system is used for converging different annular aperture scattering lights to corresponding detection points.

[0019] The beneficial effects of the above further scheme are: compared with the traditional forward scattering laser particle size instrument, the present application can avoid using large array multi-element photodetector, improve the collection efficiency of forward scattering light energy and the signal-to-noise ratio of light signal, and improve the detection sensitivity by angle selection of the digital micromirror array to deflect and modulate the scattering light of particles with different particle sizes, and by using the scattering light focusing and collecting optical system to converge the scattering light into several single-point detectors.

[0020] Further, the aerosol flow passage comprises an aerosol particle optical detection chamber and a scattering light collimating optical system, the collimating optical system can be composed of a single lens of spherical or aspherical surface, or can be composed of a multi-lens group; the aerosol particle optical detection chamber has passages connected with the air inlet pipe and the air outlet pipe on the upper and lower sides respectively; the scattering light collimating optical system is used for collimating the scattering light of aerosol particles with different particle sizes into light parallel to the optical axis and projecting onto the digital micromirror array.

[0021] The beneficial effect of the further scheme is that the air inflow pipe and the air outflow pipe are respectively sealed to the aerosol particle optical detection chamber, and only the air inflow pipe and the air outflow pipe exchange gas with the outside world; the air inflow pipe is usually connected to the gas filtering device and the particle size cutting device at the air inlet end, and serves as a particle channel of a specific particle size; the front section of the air inflow pipe is long and has a large aperture, and the aerosol particles move at a speed close to the air flow rate after passing through the section. Aerosol particles of different particle sizes have different forward scattering angles, and the larger the particle size, the smaller the scattering angle, and the smaller the particle size, the larger the scattering angle. The focal point of the scattering light collimation optical system coincides with the aerosol detection point in the aerosol particle optical detection chamber, and is used for collimating the scattering light of aerosol particles of different particle sizes into light parallel to the optical axis.

[0022] Further, the light source shaping optical system is located between the light source and the aerosol particle optical detection chamber, and is used for shaping and converging the light beam emitted by the light source to project into the aerosol particle optical detection chamber; the light source shaping optical system forms a convergence point or a convergence line in the aerosol particle optical detection chamber, and the aerosol particles in the aerosol particle optical detection chamber pass through the convergence point or the convergence line perpendicularly to the light beam.

[0023] Further, one end of the air inflow pipe in the aerosol particle optical detection chamber is a conical nozzle structure, and the other end of the air outflow pipe outside the aerosol particle optical detection chamber is connected to the air pump.

[0024] The beneficial effect of the further scheme is that the end of the air inflow pipe is designed as a conical nozzle, so that the aerosol particles are accelerated by the air flow in a short time, and the air outflow pipe is connected to the air pump to drive the air flow and the aerosol particle flow through the detection light path of the air inflow pipe and the aerosol particle optical detection chamber.

[0025] Further, the aerosol particle optical detection chamber is provided with a front optical window and a rear optical window for light beam transmission on the front side and the rear side respectively, and the scattering light collimation optical system is installed on the rear optical window.

[0026] The beneficial effect of the further scheme is that the optical window is used for light beam transmission and detection.

[0027] Further, the spot size of the convergence point or the convergence line in the direction of the aerosol particle shuttle path is 10-500 um, and the aerosol particle optical detection chamber is provided with a light extinction trap.

[0028] The beneficial effect of the further scheme is that the light extinction trap is used for reflecting and absorbing direct light source energy, so as to avoid the direct light of the light source that does not pass through the aerosol particle scattering from entering the scattering light collection system and interfering with the collection of the particle scattering signal.

[0029] Further, the digital micromirror array assembly is a concave digital micromirror array, each micro-mirror in the concave digital micromirror array adopts a concave spherical surface structure or a parabolic surface structure with beam converging effect.

[0030] The beneficial effect of the further scheme is that the concave digital micromirror array is composed of a plurality of micro-electromechanical (MEMS) small mirrors, each micro-mirror is composed of a concave spherical surface or a parabolic surface with beam converging effect, and the reflection of light can be adjusted by controlling the deflection of the micro-electromechanical structure through electrical parameters. By adjusting the reflection angle of the micro-mirror on the different aperture annular bands to different reflection angles, the deflection modulation of the annular aperture light is realized; the scattering light of different apertures corresponds to the scattering of particles of different sizes, and the scattering light of different particle sizes is collected independently by converging the light to different detectors through the concave digital micromirror array. The layout of the detection points can be adjusted by the parameters of the digital micromirror, so that the layout is relatively free.

[0031] Further, the light source shaping optical system is located between the light source and the aerosol flow channel, and the aerosol flow channel includes an aerosol inlet pipe, and the light source shaping optical system is used to expand the light beam emitted by the light source into parallel light and enter the detection area of the aerosol inlet pipe.

[0032] The beneficial effect of the further scheme is that the light beam emitted by the light source is expanded into parallel light and enters the detection area, and the detection area is a cylindrical area where the laser beam aperture and the air flow channel overlap, and the measurement object is the particle group in the area.

[0033] Further, the concave digital micromirror array is provided with an extinction trap in the middle. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 The structure principle schematic diagram of one embodiment of the present application is shown in the figure.

[0035] Figure 2 The structure principle schematic diagram of another embodiment of the present application is shown in the figure.

[0036] Figure 3 The schematic diagram of the annular aperture distribution of the digital micromirror array in the present application is shown in the figure.

[0037] In the drawings, the components represented by each reference numeral are listed as follows:

[0038] 1, light source; 2, light shaping optical system; 3, aerosol particle optical detection chamber; 4, air inlet pipe; 5, air outlet pipe; 6, scattered light collimation optical system; 7, light extinction trap; 8, digital micromirror array; 9, scattered light focusing and collecting optical system; 10, distributed single-point detector; 11, aerosol inlet pipe; 12, concave digital micromirror array; 13, detection area. DETAILED DESCRIPTION

[0039] The principles and features of the present application are described below in conjunction with the accompanying drawings, which are only used to explain the present application and are not intended to limit the scope of the present application.

[0040] Example 1

[0041] As shown in Figure 1 and Figure 2 , an aerosol particle optical detection device of the present embodiment comprises:

[0042] a light source 1 for emitting a light beam to irradiate aerosol particles into a detection area 13; the light source 1 can be a monochromatic semiconductor laser, an LED or a wide-band xenon lamp light source, etc.;

[0043] an aerosol flow passage for scattered light detection of aerosol particles;

[0044] a digital micromirror array assembly for deflection modulation and convergence of scattered light of different annular apertures;

[0045] a distributed single-point detector 10 for receiving the converged annular aperture scattered light and converting the light signal into an electrical signal.

[0046] The distributed single-point detector 10 is arranged at the corresponding position according to the position of the convergence point, and the number of detection points used is determined by the particle size channel distinguished by the digital micromirror array, which can be a distributed independent number of detection points or a linear array detection array.

[0047] The device of the present embodiment for aerosol particle light scattering counting detection through a digital micromirror array and a distributed single-point detector can converge the scattered light of different particle sizes to a plurality of single-point detectors through the angle selection of each micro-mirror in the digital micromirror array, which can avoid the use of a large-area multi-element photodetector, improve the collection efficiency of forward scattering light energy, and does not need to calibrate the F-D curve, so there is no problem of inaccurate particle size detection caused by Mie resonance zone; in addition, multiple particles can also be detected when they enter the particle counter detection area at the same time, thereby improving the upper limit of the detection concentration of the aerosol particle counter.

[0048] Example 2

[0049] As shown in Figure 1The aerosol particle optical detection device of the embodiment comprises:

[0050] A light source 1 is arranged to emit a light beam to irradiate the aerosol particles in the detection area 13; the light source 1 can be a monochromatic semiconductor laser, an LED or a wide-band xenon lamp light source, etc.

[0051] An aerosol flow channel is arranged to detect the scattered light of the aerosol particles.

[0052] A digital micromirror array assembly is arranged to modulate and converge the scattered light of different annular apertures.

[0053] A distributed single-point detector 10 is arranged to receive the converged annular aperture scattered light and convert the light signal into an electrical signal.

[0054] The distributed single-point detector 10 is arranged at a corresponding position according to the position of the convergence point, and the number of detection points used is determined by the particle size channel distinguished by the digital micromirror array. The detection points can be distributed and independent, or can be a linear array.

[0055] As shown in Figure 1 The digital micromirror array assembly comprises:

[0056] A digital micromirror array 8 is arranged to modulate the scattered light of different annular apertures; the digital micromirror array 8 is composed of a plurality of micro-electromechanical (MEMS) small mirrors, each of which can be controlled by a micro-electromechanical structure to adjust the reflection of light by adjusting the deflection of the mirror. As shown in Figure 3 By adjusting the reflection angle of the micro-mirror on the different aperture annular bands to different reflection angles, the deflection modulation of the annular aperture light is realized; the scattered light of different apertures corresponds to the scattering of particles of different sizes, and is converged to different distributed single-point detectors 10 by the subsequent scattered light focusing and collecting optical system 9, so that the scattered light of particles of different sizes can be collected independently. The position layout of the detection points can be adjusted by the parameters of the digital micromirror, so that it can be arranged relatively freely.

[0057] A scattered light focusing and collecting optical system 9 is arranged between the digital micromirror array 8 and the distributed single-point detector 10, and is used to converge the scattered light of different annular apertures to the corresponding detection points.

[0058] Compared with the traditional forward scattering laser particle size analyzer, the embodiment can modulate the scattered light of particles of different sizes by the angle selection of the digital micromirror array, and converge the scattered light to a plurality of single-point detectors by the scattered light focusing and collecting optical system, so that the use of a large-area multi-element photodetector can be avoided, the collection efficiency of the forward scattering light energy and the signal-to-noise ratio of the light signal can be improved, and the detection sensitivity can be improved.

[0059] AsFigure 1 As shown, the aerosol flow channel in this embodiment includes an aerosol particle optical detection chamber 3 and a scattered light collimating optical system 6. The aerosol particle optical detection chamber 3 is used for detecting the scattered light of aerosol particles, and the scattered light detection is used for particle counting and particle size calculation. The upper and lower sides of the aerosol particle optical detection chamber 3 have channels connected to the airflow inlet pipe 4 and the airflow outlet pipe 5, respectively. The scattered light collimating optical system 6 is used to collimate the scattered light of aerosol particles of different sizes into light parallel to the optical axis and project it onto the digital micromirror array 8. The airflow inlet pipe 4 and the airflow outlet pipe 5 are respectively sealed to the aerosol particle optical detection chamber 3, and gas exchange with the outside can only occur through the airflow inlet and outlet pipes. The airflow inlet pipe 4 is usually connected to the gas filter device and particle size cutting device at the inlet end. As a particle channel for a specific particle size, the front section of the airflow inlet pipe 4 is long and has a large aperture. After passing through this section, the movement speed of aerosol particles tends to be the same as the airflow speed. Aerosol particles of different sizes produce forward-scattered light at different angles. Larger particles produce scattered light at smaller angles, while smaller particles produce scattered light at larger angles. The focal point of the scattered light collimating optical system 9 coincides with the aerosol detection point in the aerosol particle optical detection chamber 3, and is used to collimate the scattered light from aerosols of different sizes into light parallel to the optical axis.

[0060] like Figure 1 As shown, this embodiment also includes a light source shaping optical system 2, located between the light source 1 and the aerosol particle optical detection chamber 3, for shaping and focusing the light beam emitted by the light source into the aerosol particle optical detection chamber 3; the light source shaping optical system 2 forms a converging point or converging line in the aerosol flow channel, and the aerosol particles in the aerosol particle optical detection chamber 3 are perpendicular to the light beam and pass through the converging point or converging line. The spot size of the converging point or converging line in the direction of the aerosol particle shuttle path is 10-500 μm.

[0061] like Figure 1 As shown, in this embodiment, the end of the airflow inlet pipe 4 located inside the aerosol particle optical detection chamber 3 is a conical nozzle structure, and the end of the airflow outlet pipe 5 located outside the aerosol particle optical detection chamber 3 is connected to an air pump. The conical nozzle design at the end of the airflow inlet pipe accelerates the aerosol particles by the airflow in a short time. The airflow outlet pipe is connected to the air pump, driving the airflow and aerosol particles through the detection optical path of the airflow inlet pipe and the aerosol particle optical detection chamber.

[0062] like Figure 1 As shown, in this embodiment, the aerosol particle optical detection chamber 3 has a front optical window and a rear optical window on its front and rear sides, respectively, for beam transmission. The scattered light collimating optical system 9 is mounted on the rear optical window. The optical windows are used for beam transmission and detection.

[0063] likeFigure 1 As shown, the aerosol particle optical detection chamber 3 is provided with an extinction trap 7. The extinction trap is used to reflect and absorb direct light source energy, avoiding the direct light of the light source that does not pass through the aerosol particle scattering from entering the scattering light collection system, and interfering with the collection of particle scattering signals.

[0064] Figure 3 For an example of a ring aperture distribution of a digital micromirror array, the ring aperture is a, b, c, d, e, f from outside to inside. The digital micromirror plane is arranged at an angle to the optical axis (preferably 45°, which can be adjusted according to actual conditions), and the digital micromirror plane can fold the light path by 90° at an angle of 45°. The ring aperture regions a-e correspond to the outer aperture to the inner aperture, and the corresponding particle size ranges from small particle size to large particle size. The deflection angle difference between adjacent ring bands is 1°-5°, so that the deflection angle difference between the light beams reflected by each aperture is 2°-10°. Because the extinction trap 7 blocks the non-particle scattering light (laser direct light beam), there should be no light beam irradiation at the center aperture f. When the extinction trap 7 is removed or the extinction effect of the extinction trap 7 is not good, the micro-mirrors at the aperture f can be uniformly deflected by a large angle, so that the light beams of this part of the aperture deviate out of the aperture and field of view of the scattering light focusing and collecting optical system 9, thereby excluding interference signals and improving the signal-to-noise ratio of each particle size channel.

[0065] Compared with the traditional forward scattering laser particle size analyzer, the present embodiment can avoid using a large-area multi-element photodetector by selecting the angle of the digital micromirror array to converge the scattering light of particles of different sizes into several single-point detectors, while improving the collection efficiency of forward scattering light energy and the signal-to-noise ratio of the light signal, thereby improving the detection sensitivity. Specifically, the digital micromirror array can deflect all the scattering light energy belonging to the corresponding particle size dispersed on the complete ring strip to a consistent angle, and converge it to a distributed single-point detector through the subsequent scattering light focusing and collecting optical system, i.e., concentrate the dispersed energy on one detector. Under the same device hardware noise, the intensity of the collected light signal can be greatly improved, the signal-to-noise ratio is improved, and the detection sensitivity (lower detection limit) is improved. The fan-shaped detector used in the prior art is a local part of the circular ring detector, and the total scattering light energy that can be collected is significantly lower than that of the ring-shaped detector, and the energy collection efficiency is much lower than that of the present scheme.

[0066] Compared with the traditional dust particle counter, the single-point detectors at different positions in the present embodiment correspond to different particle size channels, and there is no need to calibrate the F-D curve (the particle size of the traditional angular scattering particle counter is related to the scattering light intensity, and the function relationship between the light intensity F and the particle size D needs to be calibrated, but the function is not monotonic). Therefore, the problem of inaccurate particle size detection caused by Mie resonance zone does not exist.

[0067] Compared with the traditional dust particle counter, the present embodiment can detect multiple particles entering the detection area of the particle counter at the same time, thereby improving the upper limit of the detection concentration of the aerosol particle counter (the traditional scattering particle counter will produce particle size detection deviation and particle number missing detection when more than or equal to two particles enter the detection area at the same time). Specifically, the present embodiment can converge the scattered light of multiple aerosol particles entering the detection area at the same time to different single-point detectors according to the particle size. The particles between different particle sizes do not interfere with each other, and the counting form is changed from the traditional light pulse counting to counting the light pulses and total light intensity values falling on the corresponding particle size detector to count the particles, so that the upper limit of the concentration detection of the device can be greatly improved.

[0068] Embodiment 3

[0069] As shown in Figure 2 , an aerosol particle optical detection device according to the present embodiment comprises:

[0070] a light source 1 for emitting a light beam to irradiate the aerosol particles entering the detection area 13; the light source 1 can be a monochromatic semiconductor laser, an LED or a wide-band xenon lamp light source, etc.

[0071] an aerosol flow channel for scattered light detection of the aerosol particles;

[0072] a digital micromirror array assembly for deflection modulation and convergence of scattered light of different annular apertures;

[0073] a distributed single-point detector 10 for receiving the converged annular aperture scattered light and converting the light signal into an electrical signal.

[0074] The distributed single-point detector 10 is arranged at the corresponding position according to the position of the convergence point, and the number of detection points used is determined by the particle size channels distinguished by the digital micromirror array. It can be a distributed independent number of detection points, or a linear array detection array.

[0075] As shown in Figure 2As shown, the digital micromirror array assembly of the embodiment is a concave digital micromirror array 12, each micro-mirror in the concave digital micromirror array 12 adopts a concave spherical surface structure or a parabolic surface structure with beam converging effect. The concave digital micromirror array is composed of a plurality of micro-electro-mechanical (MEMS) small mirrors, each micro-mirror is composed of a concave spherical surface or a parabolic surface with beam converging effect, and the reflection of light can be adjusted by deflecting the micro-mirror through electrical parameters. By adjusting the reflection angle of the micro-mirror on the different aperture annular bands to different reflection angles, the deflection modulation of the annular aperture light is realized; the scattering light of different apertures corresponds to the scattering of particles of different sizes, and the scattering light of particles of different sizes is collected on different detectors through the concave digital micromirror array, so that the scattering light of particles of different sizes can be independently collected. The layout of the detection points can be adjusted by the parameters of the digital micromirror, so that the layout is relatively free.

[0076] As shown, Figure 2 The embodiment also includes a light source shaping optical system 2 located between the light source 1 and the aerosol flow channel; the aerosol flow channel includes an aerosol inlet pipe 11, which is located between the light source shaping optical system 2 and the concave digital micromirror array 12, and the gas inlet direction is perpendicular to the light beam direction; the aerosol inlet pipe 11 is usually connected with the gas filtering device and the particle size cutting device at the gas inlet end, serving as a particle channel of a specific particle size; the light source shaping optical system 2 is used to expand the light beam emitted by the light source into parallel light, which enters the detection area 13 of the aerosol inlet pipe 11. The detection area 13 is a cylindrical area where the laser beam aperture and the gas flow channel overlap, and the measurement object is the particle group in the area.

[0077] As shown, Figure 2 The concave digital micromirror array 12 is provided with an extinction trap 7 in the middle.

[0078] Compared with the traditional forward scattering laser particle size analyzer, the embodiment can avoid using a large-area multi-element photoelectric detector and improve the collection efficiency of the forward scattering light energy by selecting the angles of each micro-mirror in the digital micromirror array to respectively converge the scattering light of particles of different sizes into a plurality of single-point detectors.

[0079] The device for counting and detecting the light scattering of aerosol particles through the digital micromirror array and the distributed single-point detector can avoid using a large-area multi-element photoelectric detector and improve the collection efficiency of the forward scattering light energy by selecting the angles of each micro-mirror in the digital micromirror array to respectively converge the scattering light of particles of different sizes into a plurality of single-point detectors, and does not need to calibrate the F-D curve, so there is no problem of inaccurate particle size detection caused by the Mie resonance zone; in addition, multiple particles can be detected when they enter the particle counter detection area at the same time, so that the upper limit of the detection concentration of the aerosol particle counter can be improved.

[0080] In the description of the application, it is to be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the application.

[0081] In the description of the application, "a plurality of" means at least two, for example, two, three, etc., unless otherwise explicitly specified and limited.

[0082] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0083] In the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature, which can be direct contact between the first and second features, or indirect contact between the first and second features through an intermediate medium. Moreover, the first feature "above", "above" and "above" the second feature can be directly above or obliquely above the first feature, or only indicate that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature can be directly below or obliquely below the first feature, or only indicate that the horizontal height of the first feature is less than that of the second feature.

[0084] In the description of the specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are contained in at least one embodiment or example of the present application. In the specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any suitable manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the specification and the features of the different embodiments or examples without contradiction.

[0085] Although the embodiments of the present application have been shown and described above, it is understood that the above-described embodiments are exemplary and are not to be construed as limiting the present application, and the person skilled in the art can make changes, modifications, replacements and variations to the above-described embodiments within the scope of the present application.

Claims

1. An aerosol particle optical detection device, characterized by, include: A light source is used to emit a beam of light to illuminate aerosol particles entering the detection area; Aerosol flow channel for detecting scattered light from aerosol particles; Digital micromirror array components are used for deflection, modulation, and focusing of scattered light with different annular apertures; A distributed single-point detector is used to receive the converged scattered light from the annular aperture and convert the optical signal into an electrical signal; The aerosol flow channel includes an aerosol particle optical detection chamber and a scattered light collimating optical system. The aerosol particle optical detection chamber has channels on its upper and lower sides that are connected to the airflow inlet and outlet pipes, respectively. The scattered light collimating optical system is used to collimate the scattered light from aerosol particles of different sizes into light parallel to the optical axis and project it onto the digital micromirror array. The digital micromirror array assembly includes: A digital micromirror array is used for deflection and modulation of scattered light with different annular apertures; the digital micromirror planes of the digital micromirror array are arranged at an angle to the optical axis. A scattered light focusing and acquisition optical system is used to converge scattered light from different annular apertures to the corresponding detection point; Alternatively, the digital micromirror array assembly is a concave digital micromirror array, and each micromirror in the concave digital micromirror array adopts a concave spherical surface structure or a parabolic surface structure that also has the function of beam converging.

2. The apparatus of claim 1, wherein It also includes a light source shaping optical system located between the light source and the aerosol particle optical detection chamber, used to shape and converge the light beam emitted by the light source into the aerosol particle optical detection chamber; the light source shaping optical system forms a convergence point or convergence line in the aerosol particle optical detection chamber, and the aerosol particles in the aerosol particle optical detection chamber are perpendicular to the light beam and pass through the convergence point or convergence line.

3. The aerosol particle optical detection device according to claim 1, characterized in that, The airflow inlet pipe has a conical nozzle structure at one end inside the aerosol particle optical detection chamber, and the airflow outlet pipe is connected to an air pump at the other end outside the aerosol particle optical detection chamber.

4. The apparatus of claim 1, wherein the optical detection system comprises a laser source and a detector. The aerosol particle optical detection chamber has a front optical window and a rear optical window for beam transmission on its front and rear sides, respectively, and the scattered light collimating optical system is installed on the rear optical window.

5. The apparatus of claim 2, wherein the optical detection system comprises a laser source and a detector. The spot size of the convergence point or convergence line in the direction of the aerosol particle shuttle path is 10-500um; the aerosol particle optical detection chamber is equipped with an extinction trap.

6. The apparatus of claim 1, wherein the optical detection system comprises a laser source and a detector. It also includes a light source shaping optical system located between the light source and the aerosol flow channel; the aerosol flow channel includes an aerosol inlet pipe, and the light source shaping optical system is used to expand the beam emitted by the light source into parallel light and direct it into the detection area of ​​the aerosol inlet pipe.

7. The aerosol particle optical detection device according to claim 1, characterized in that, The concave digital micromirror array has an extinction trap in the middle.

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