CN217819911U - Particle counter - Google Patents

Abstract

The utility model provides a particle counter, which comprises a shell, a light emitter, a light shaping component, a sampling component, a scattered light collecting component and a light collecting structure; the light emitter emits light beams, and the light beams form a light working area after passing through the light shaping structure; the sampling assembly, the scattered light collecting assembly and the light collecting structure are combined with the shell; the light emitter and the light shaping component are sequentially arranged on the channel path along the light beam propagation path; the optical shaping assembly comprises at least one lens group, the lens group comprises a first plano-convex cylindrical lens and a second plano-convex cylindrical lens, the convex surface of the first plano-convex cylindrical lens and the convex surface of the second plano-convex cylindrical lens are arranged oppositely, and the first plano-convex cylindrical lens and the second plano-convex cylindrical lens are perpendicular to the focusing direction of light beams.

Description

Particle counter

Technical Field

The present invention relates to the field of optical detection devices, and more particularly to a particle counter.

Background

The particle counter is an instrument for counting dust particles by using the principle of light scattering, and the working principle of the particle counter is that a certain flow of dust-containing gas passes through a bundle of strong light to make particles emit scattered light, the scattered light is projected onto a photoelectric detector through a condenser lens, an optical pulse is changed into an electric pulse, and the number of particles is obtained according to the pulse number. The dust-containing gas scatters particles by strong light in a space serving as an optical working area, and the optical working area is required to be uniform in order to ensure the accuracy of a measurement result.

In order to make the light beam emitted by the light source perpendicular to the direction of light beam propagation in the light working area and the light energy intensity distribution of the light working area along the direction of light beam propagation uniform, the light beam is generally adjusted by arranging an optical lens between the light source and the light working area. However, the existing optical lenses such as the diaphragm, the grating, the spherical mirror, the aspherical mirror, etc. have advantages and disadvantages, but cannot achieve ideal shaping effects independently. For example, spherical mirrors tend to cause increased aberrations and distortion, resulting in significant image blur, distortion of the field of view, and a narrow field of view; the aspherical mirror can correct images, so that the problem of distortion of the visual field is solved, and the distortion is smaller; the cylindrical mirror can effectively reduce spherical aberration and chromatic aberration. In the prior art, a plurality of optical lens combinations are mostly adopted to shape the light beam, for example, the aspherical mirror and the cylindrical mirror are combined and then placed in the direction of semiconductor light beam transmission, the aspherical mirror is used for light beam collimation, and the cylindrical mirror is used for light beam compression, but the size of a particle counter is considered, so that the scheme has very strict requirements on the distance between the aspherical mirror and the light source, and the closer the distance between the aspherical mirror and the light source is required to be, the better the distance between the aspherical mirror and the light source is required to be.

In view of the above, there is a need in the art for an improved beam shaping structure for existing particle counters.

Disclosure of Invention

In view of the above, the present invention provides a particle counter, which provides an optical working area with uniform energy and regular shape for the particle counter by improving the optical shaping structure.

In order to achieve the above object, the present invention provides a particle counter, comprising a housing, a light emitter, a light shaping assembly, a sampling assembly, a scattered light collecting assembly, and a light collecting structure; the light emitter emits light beams, and the light beams form a light working area after passing through the light shaping structure; the sampling assembly, the scattered light collection assembly, and the light collection structure are disposed in conjunction with the housing; the light emitter and the light shaping component are sequentially arranged on a channel path along a light beam propagation path; the light shaping assembly comprises at least one lens group, the lens group comprises a first plane-convex cylindrical lens and a second plane-convex cylindrical lens, the convex surface of the first plane-convex cylindrical lens and the convex surface of the second plane-convex cylindrical lens are oppositely arranged, and the first plane-convex cylindrical lens and the second plane-convex cylindrical lens are mutually vertical to the focusing direction of the light beam.

Preferably, a cylindrical axis direction of the first plano-convex cylindrical lens is an X direction, a cylindrical axis direction of the second plano-convex cylindrical lens is a Y direction, both the X direction and the Y direction are perpendicular to an axis direction of the light beam, and the X direction and the Y direction are perpendicular to each other.

Preferably, the light beam firstly passes through the plane of the first plano-convex cylindrical lens and then passes through the convex surface of the first plano-convex cylindrical lens in the process of propagating.

Preferably, the light beam firstly passes through the convex surface of the second plano-convex cylindrical lens and then passes through the plane of the second plano-convex cylindrical lens in the process of propagation.

Preferably, the channel has a first opening corresponding to the plane of the first plano-convex cylindrical lens, the channel has a second opening corresponding to the plane of the second plano-convex cylindrical lens, the first opening and the second opening share a light beam optical axis, and the aperture of the first opening is larger than that of the second opening.

Preferably, the first opening and the second opening are circular openings, and the aperture of the first opening is 1-3 times the aperture of the second opening.

Preferably, when the light shaping assembly comprises a plurality of the mirror groups, a plurality of the mirror groups are coaxially arranged, and an angular offset around the central axis direction of the light beam is arranged between the plurality of the mirror groups.

Preferably, the light emitter is provided in combination with the channel in which the light shaping component is mounted, the channel having an embedded location in which the mirror group is mounted.

Preferably, the housing may be made up of several detachably connected parts.

Compared with the prior art, the particle counter disclosed by the invention has the advantages that: the light shaping component of the particle counter adopts the cylindrical lens with the convex surfaces oppositely arranged to realize the shaping of the light beam, the distance between the light source and the light shaping component does not need to be strictly controlled, the light intensity of the light working area can be improved by improving the light intensity of the light beam of the light source, and the qualified light working area can be obtained.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic diagram of a particle counter according to the present application.

Fig. 2 is a schematic diagram of a particle counter according to the present application.

Figure 3 shows a cross-sectional view of the light shaping assembly mounted in a housing.

Fig. 4 is a schematic structural diagram of the light shaping assembly including a lens group.

Fig. 5 is a schematic structural diagram of the light shaping assembly including a plurality of lens groups.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 1 to 3, a particle counter according to the present application includes a housing 10, a light emitter 11, a light shaping component, a sampling component, a scattered light collecting component, and a light collecting structure 15, wherein the light emitter 11 emits a light beam 16, and the light beam 16 passes through the light shaping structure to form a light working area 4. Sampling subassembly, scattered light collection assembly and light collection structure 15 all combine the setting with shell 10, and sampling subassembly, scattered light collection assembly all correspond the setting with light workspace 4. The inside of the housing 10 has a channel for transmitting the light beam 16, the light emitter 11 and the light shaping assembly are sequentially disposed on the channel along the light beam transmission path, specifically, referring to fig. 4, the light shaping assembly includes at least one lens group, the lens group includes a first planar-convex cylindrical lens 121 and a second planar-convex cylindrical lens 131, a convex surface of the first planar-convex cylindrical lens 121 and a convex surface of the second planar-convex cylindrical lens 131 are disposed oppositely, and the first planar-convex cylindrical lens 121 and the second planar-convex cylindrical lens 131 are perpendicular to each other with respect to the focusing direction of the light beam 16. The beam 16 is collimated and compressed by the mirror assembly.

The particle counter further comprises a processing control module 5, and the processing control module 5 is connected with the scattered light collecting assembly to realize particle counting. The sampling assembly and the scattered light collecting assembly are both arranged corresponding to the optical working area 4, and are used for scattering particles entering the optical working area through the sampling assembly, at least part of scattered light is received by the scattered light collecting assembly to obtain scattered light signals, and based on the prior art, the application is not limited by specificity.

Preferably, the optical axis of the light beam 16 intersects an axial meridian of the first plano-convex lens 121 and an axial meridian of the second plano-convex lens 131.

Preferably, the light emitter 11 and the light shaping component are arranged on the channel path in sequence on a common beam optical axis.

The light shaping assembly of the particle counter adopts the cylindrical lens with the convex surfaces oppositely arranged to realize the shaping of the light beam, the distance between the light source and the light shaping assembly does not need to be strictly controlled, the light source does not need to be strictly arranged at the focus of each light shaping lens for collimation, the light intensity of the light beam of the light source can be improved to improve the light intensity of the light working area, and the light beam is compressed in the shaping direction of the light beam through the first plano-convex lens and the second plano-convex lens to obtain the qualified light working area.

Specifically, as shown in fig. 4, the X direction is a cylindrical axis direction of the first plano-convex cylindrical lens 121, the Y direction is a cylindrical axis direction of the second plano-convex cylindrical lens 131, both the X direction and the Y direction are perpendicular to an axial direction of the light beam 16, and the X direction and the Y direction are perpendicular to each other. The first plano-convex cylindrical lens 121 performs convergence collimation on the light beam 16 perpendicular to the cylindrical axis direction thereof, that is, the first plano-convex cylindrical lens 121 performs convergence collimation on the light beam 16 in the Y direction, that is, the first plano-convex cylindrical lens 121 performs refraction on the light beam 16 in the Y direction; the second plano-convex cylindrical lens 131 performs convergence collimation on the light beam 16 perpendicular to the cylindrical axis direction thereof, that is, the second plano-convex cylindrical lens 131 performs convergence collimation on the light beam 16 in the X direction, that is, the second plano-convex cylindrical lens 131 performs refraction on the light beam 16 in the X direction.

The scattered light beam 16 emitted from the light emitter 11 enters perpendicularly to the plane of the first plano-convex cylindrical lens 121, exits through the convex surface of the first plano-convex cylindrical lens 121, is compressed in the Y direction, enters through the convex surface of the second plano-convex cylindrical lens 131, exits through the plane of the second plano-convex cylindrical lens 131, and is compressed in the X direction.

By adopting the light shaping component, the distance between the light source and the light shaping component does not need to be strictly limited, the light intensity of the light working area 4 can be improved by improving the light intensity of the light emitting device emergent light beam 16 under the condition that the distance between the light source and the light shaping component is far, the adjustment is convenient, and the measurement precision of the particle counter is improved.

Referring to fig. 3, a first opening is formed in the channel corresponding to the plane of the first plano-convex cylindrical lens 121, a second opening is formed in the channel corresponding to the plane of the second plano-convex cylindrical lens 131, the first opening and the second opening share the optical beam axis, the aperture of the first opening is larger than that of the second opening, the first opening limits the optical beam entering the first plano-convex cylindrical lens, the second opening limits the optical beam leaving the second plano-convex lens, and the optical beam compressed by the first plano-convex lens and the second plano-convex lens can better intercept the optical beam for forming the optical working area through the second opening. Preferably, when the first opening and the second opening are circular openings, the aperture of the first opening is 1-3 times, e.g. 1.2, 1.5, 1.8, 2.0, 2.5, 3.0 times, the aperture of the second opening. Preferably, the plane of the first plano-convex cylindrical lens 121 completely covers the first opening, and the plane of the second plano-convex cylindrical lens 131 completely covers the second opening, where the vertical projection of the first plano-convex cylindrical lens 121 is larger than the vertical projection of the first opening and covers the first opening, and the vertical projection of the second plano-convex cylindrical lens 131 is larger than the vertical projection of the second opening and covers the second opening, on the plane perpendicular to the optical axis of the outgoing light beam from the first opening.

Preferably, the first opening is attached to the plane of the first plano-convex cylindrical lens 121, and the second opening is attached to the plane of the second plano-convex cylindrical lens 131.

As shown in fig. 5, when the light shaping assembly includes a plurality of lens groups, the axial meridian of the first plano-convex cylindrical lens and the second plano-convex cylindrical lens in each lens group intersects with the optical axis of the light beam, preferably, the plurality of lens groups are disposed in a manner of sharing the optical axis of the light beam, and preferably, the plurality of lens groups have an angular offset around the optical axis of the light beam 16, so as to optimize the shaping effect on the light beam 16 and increase the uniformity of the light energy intensity distribution of the shaped light beam 16. At this time, the first opening corresponds to the plane of the first plano-convex cylindrical lens, into which the light beam enters along the propagation direction, and the second opening corresponds to the plane of the last second plano-convex cylindrical lens, into which the light beam enters along the propagation direction.

In the present application, there is no specific limitation on the relative position of the first plano-convex cylindrical lens 121 and the second plano-convex cylindrical lens 131 in one lens group, that is, there is no specific limitation on the distance between the two convex surfaces. The light beam here does not include stray light on the optical path of the light beam. As a practical way, the light beam emitted from the first plano-convex cylindrical lens 121 is incident on the second plano-convex cylindrical lens 131. Considering that the larger the distance between the second plano-convex cylindrical lens 131 and the first plano-convex cylindrical lens 121 is, the larger the light spot of the cross section of the light beam perpendicular to the optical axis of the light beam formed by the divergence angle is, that is, the larger the required planar size of the second plano-convex cylindrical lens 131 is, the smaller the distance between the convex surface of the first plano-convex cylindrical lens 121 and the convex surface of the second plano-convex cylindrical lens 131 is, the better the case is.

Preferably, the particle counter further comprises an optical filtering structure 14, the light emitter 11, the light shaping assembly and the optical filtering structure 14 are sequentially arranged on the channel path in a way of sharing the light beam optical axis, and the light beam 16 passes through the light shaping structure and the optical filtering structure 14 to form the optical working area 4. In this embodiment, the light filtering structure 14 has a hole for limiting the aperture of the light beam 16 entering the hole, and the propagation process of the light beam in the hole of the light filtering structure 14 is further limited by the hole, so as to further realize the filtering of stray light. The light filtering structure 14 may be a part of a housing, and is formed by the housing, the hole of the light filtering structure 14 is a part of the housing channel, and one end of the hole of the light filtering structure 14 is opened as the second opening. The pore channel may be a circular through hole, for example, the central axis of the circular through hole is arranged to coincide with the central axis of the light beam 16, the aperture of the circular through hole is 2.8mm, the light beam 16 passes through the circular through hole to obtain a light spot perpendicular to the central axis of the light beam 16, and a volume of the light beam with a light spot size of 1.20mm × 2.85mm is used as the light working area. The aperture may also progressively restrict the aperture of the beam 16 and the perimeter wall of the aperture may also define a space in communication with the aperture. And are not specifically described herein. In other embodiments, the light filtering structure may also be an aperture stop.

Referring to fig. 3, the channel includes a light source section 101, a light shaping section 102, a light filtering section 103 and a main cavity section 104 distributed in sequence, the light emitter 11 is disposed in combination with the light source section 101, the light shaping assembly is installed in the light shaping section 102, the light filtering structure 14 is disposed in the light filtering section 103 or the light filtering section 103 itself forms the light filtering structure 14, and the light work area 4 is formed in the main cavity section 104. Preferably, the light shaping section 102 has an embedded position for mounting the lens group.

It should be noted that the housing may be composed of several detachably connected parts to facilitate the installation of each lens in the lens assembly, and the peripheral wall of the housing channel may be blackened, or may be made of a light-absorbing material or have a light-absorbing coating to absorb the light incident on the surface thereof, which is not limited herein. The light collection structure 15 stops the propagation of the light beam after the photosensitive region in the direction of propagation of the light beam, and the light collection structure 15 may employ a light trap. The sampling module comprises an air inlet nozzle 31 for sample airflow 33 to enter the measuring cavity and an air outlet nozzle 32 for sample airflow to leave the measuring cavity, and the optical working areas 4 are symmetrically distributed along the central axis of the air inlet nozzle 31; the sample gas flow 33 contains particles to be measured. The scattered light collecting component comprises a photoelectric detector 21 and a light reflector 22, the light reflector 22 collects scattered light of particles to be detected and reflects the scattered light to the photoelectric detector 21, and the photoelectric detector 21 converts the received scattered light of the particles to be detected into an electric signal; the photodetector 21 and the light reflector 22 are arranged to satisfy a geometric-optical relationship, a portion of scattered light of a particle to be detected can be directly received by the photodetector 21, a portion of scattered light is collected by the light reflector 22 and then transmitted to the photodetector 21, and the photodetector 12, such as a photodiode, converts a received optical signal into an electrical signal. The processing control module 5 includes an amplifying circuit and an acquisition circuit connected to the output end of the photodetector 21, wherein the amplifying circuit amplifies and/or converts the electrical signal of the photodetector 21, for example, converts the photocurrent of the photodetector into a voltage pulse signal; the acquisition circuit acquires a voltage pulse signal and transmits the voltage pulse signal to the comparator to realize particle counting, and based on the prior art, the signal conversion and counting principle of the particle counter are not specifically described.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (9)

1. A particle counter comprising a housing, a light emitter, a light shaping component, a sampling component, a scattered light collection component, and a light collection structure; the light emitter emits light beams, and the light beams form a light working area after passing through the light shaping structure; the sampling assembly, the scattered light collection assembly, and the light collection structure are disposed in conjunction with the housing; the light emitter and the light shaping component are sequentially arranged on a channel path along a light beam propagation path; the light shaping assembly comprises at least one lens group, the lens group comprises a first plane-convex cylindrical lens and a second plane-convex cylindrical lens, the convex surface of the first plane-convex cylindrical lens and the convex surface of the second plane-convex cylindrical lens are oppositely arranged, and the first plane-convex cylindrical lens and the second plane-convex cylindrical lens are mutually vertical to the focusing direction of the light beam.

2. The particle counter of claim 1, wherein a cylinder axis direction of the first plano-convex cylindrical lens is an X direction, a cylinder axis direction of the second plano-convex cylindrical lens is a Y direction, the X direction and the Y direction are perpendicular to an axial direction of the light beam, and the X direction and the Y direction are perpendicular to each other.

3. The particle counter of claim 1, wherein said light beam propagates first through a plane of said first plano-convex cylindrical lens and then through a convex surface of said first plano-convex cylindrical lens.

4. The particle counter of claim 2, wherein said light beam travels first through a convex surface of said second plano-convex cylindrical lens and then through a flat surface of said second plano-convex cylindrical lens.

5. The particle counter of claim 1, wherein the channel has a first opening corresponding to a plane of the first plano-convex cylindrical lens, the channel has a second opening corresponding to a plane of the second plano-convex cylindrical lens, the first opening and the second opening share a common optical axis, and an aperture of the first opening is larger than an aperture of the second opening.

6. The particle counter of claim 5, wherein the first opening and the second opening are circular openings and the first opening has an aperture 1-3 times the aperture of the second opening.

7. The particle counter of claim 1, wherein when said light shaping assembly comprises a plurality of said mirror groups, a plurality of said mirror groups are coaxially disposed with an angular offset therebetween about a central axis of said light beam.

8. The particle counter of claim 1, wherein said light emitter is disposed in conjunction with said channel, said light shaping component being mounted in said channel, said channel having an inset location in which said set of mirrors is mounted.

9. The particle counter of claim 1, wherein said housing is comprised of a plurality of removably attached sections.

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