Particle counting sensor

Abstract

The utility model relates to the technical field of cleanliness detection equipment, in particular to a particle counting sensor which comprises a shell, a laser transmitter and a photoelectric receiving converter, a laser channel and a photosensitive cavity are arranged on the shell, one end of the laser channel is communicated with the photosensitive cavity, and the other end of the laser channel is used for fixing the laser transmitter; the photoelectric receiving converter is fixed on the shell, and the receiving end of the photoelectric receiving converter is arranged in the photosensitive cavity; a first extinction hole is formed in the side portion of the laser channel in the radial direction in a penetrating mode, and the inner diameter of the first extinction hole is larger than that of the laser channel. According to the utility model, the first extinction hole is formed in the side part of the laser channel along the radial direction in a penetrating manner, stray light generated by the laser beam can be absorbed through the second extinction hole, so that the stray light is not easy to enter the photosensitive cavity, the measurement precision is improved, and meanwhile, the second extinction hole is formed, so that redundant laser beams can be conveniently collected, and the measurement accuracy is improved. New stray light generated by laser beam reflection is prevented, and the measurement precision can be improved.

Description

Technical Field

[0001] The utility model relates to the technical field of cleanliness detection equipment, in particular to a particle counting sensor. Background Art

[0002] A particle counter is an important instrument for measuring the particle size and particle number concentration of particulate matter in a clean environment air. It is widely used in the cleanliness detection of industries such as semiconductors, electronics, biomedical engineering, and precision machining. Its measurement principle is based on the Mie scattering theory. When a single particle enters the photosensitive area with the air flow and is irradiated by a light beam to generate scattered light, the intensity of the scattered light is related to the particle size. By collecting the scattered light and converting it into an electrical signal through a photodetector, the measurement and counting of the particle size can be achieved, such as a laser dust particle counting sensor disclosed in CN114279942A.

[0003] Currently, the illumination system of the particle counting sensor of the particle counter mostly uses a high-power semiconductor laser. The laser beam is focused on the photosensitive area through a lens system. The scattered light generated by the particles irradiated in the sampling air flow is reflected by a mirror placed parallel to the Z-axis at a relatively far distance from the particle and then focused on the photoelectric receiving converter.

[0004] After the laser of the high-power semiconductor laser is emitted, there will be more stray light around the light beam. For the above-mentioned laser dust particle counting sensor, there is no structure designed to absorb this stray light in its laser channel, so that this stray light easily enters the photosensitive area and affects the measurement accuracy. Summary of the Utility Model

[0005] In view of this, the utility model provides a particle counting sensor. A first light extinction hole is provided in the side part of the laser channel in the radial direction, which is convenient for absorbing the stray light generated by the laser beam through the first light extinction hole, so that the stray light is not easy to enter the photosensitive cavity, improving the measurement accuracy. At the same time, by providing a second light extinction hole, it is convenient to introduce the redundant laser beam into it, preventing the laser beam from directly irradiating the photosensitive cavity and causing reflection, which is beneficial to improving the measurement accuracy.

[0006] The technical solution of the utility model is realized as follows:

[0007] The utility model provides a particle counting sensor, including a housing, a laser emitter, and a photoelectric receiving converter. Among them,

[0008] A laser channel and a photosensitive cavity are provided on the housing. One end of the laser channel is communicated with the photosensitive cavity, and the other end is used for fixing the laser emitter;

[0009] The photoelectric receiving converter is fixed on the housing, and the receiving end of the photoelectric receiving converter is arranged in the photosensitive cavity;

[0010] A first light extinction hole is provided through the side of the laser channel in the radial direction, and the inner diameter of the first light extinction hole is larger than the inner diameter of the laser channel;

[0011] A second light extinction hole is provided on the side of the photosensitive cavity away from the laser channel. The second light extinction hole is in communication with the photosensitive cavity and is coaxially arranged with the laser channel.

[0012] On the basis of the above technical solutions, preferably, the laser channel, the photosensitive cavity, the first light extinction hole, and the second light extinction hole are all in the shape of a circular hole.

[0013] On the basis of the above technical solutions, preferably, both ends of the laser channel are in the shape of stepped holes.

[0014] On the basis of the above technical solutions, preferably, at least two first light extinction holes are provided along the axial direction of the laser channel.

[0015] On the basis of the above technical solutions, preferably, a third light extinction hole is provided on the outer shell. The third light extinction hole is parallel to the first light extinction hole and penetrates through the second light extinction hole. Among them,

[0016] The aperture of the third light extinction hole is larger than the aperture of the second light extinction hole.

[0017] On the basis of the above technical solutions, preferably, the aperture of the second light extinction hole is larger than the aperture of the laser channel.

[0018] On the basis of the above technical solutions, preferably, an absorbing mechanism is further included. Among them,

[0019] An installation section and an absorbing section are formed in the second light extinction hole through the third light extinction hole. The aperture of the installation section is larger than the aperture of the absorbing section;

[0020] The absorbing mechanism is fixed in the installation section;

[0021] The aperture of one end of the absorbing section close to the third light extinction hole is larger than that of the other end, and an absorbing thread is provided on the hole wall of the end of the absorbing section close to the third light extinction hole.

[0022] On the basis of the above technical solutions, preferably, bolt holes are provided on the outer shell at positions corresponding to the absorbing mechanism, and the bolt holes are in communication with the installation section.

[0023] On the basis of the above technical solutions, preferably, an air inlet channel and an exhaust channel are provided on the outer shell. Among them,

[0024] The intake channel is arranged on one side of the laser channel and perpendicular to the laser channel, and the exhaust channel is arranged on the other side of the laser channel and perpendicular to the laser channel;

[0025] The intake channel and the exhaust channel are coaxially arranged;

[0026] Both the intake channel and the exhaust channel communicate with the photosensitive cavity.

[0027] Based on the above technical solutions, preferably, the adjacent end of the laser channel and the intake channel extends into the photosensitive cavity.

[0028] A particle counting sensor of the present invention has the following beneficial effects compared with the prior art:

[0029] (1) By radially penetrating and arranging the first extinction hole on the side of the laser channel, it is convenient to extinguish the stray light generated by the laser beam through the first extinction hole, so that the stray light is not easily introduced into the photosensitive cavity, improving the measurement accuracy. At the same time, by setting the second extinction hole, it is convenient to introduce the excess laser beam into it, preventing the laser beam from directly irradiating the photosensitive cavity and causing reflection, which is beneficial to improving the measurement accuracy.

[0030] (2) By setting the light absorption mechanism, it is convenient to absorb the laser beam through the light absorption mechanism to eliminate the excess laser beam and prevent the laser beam from reflecting.

[0031] (3) By setting both ends of the laser channel in the shape of stepped holes, it is convenient for the installation of the laser emitter and also convenient to improve the absorption effect of the laser channel on stray light through the stepped hole structure.

[0032] (4) By setting the third extinction hole and the light absorption thread, it is convenient to extinguish the stray light generated by the reflected laser beam. Description of the Drawings

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0034] Figure 1 It is a perspective view of a particle counting sensor of the present invention;

[0035] Figure 2 It is a front view of a particle counting sensor of the present invention;

[0036] Figure 3It is a sectional view taken along the A-A direction of the present utility model;

[0037] Figure 4 It is a partial perspective view of the present utility model

[0038] In the figure: 1. Outer shell; 2. Laser emitter; 3. Photoelectric receiving converter; 4. Light absorption mechanism; 101. Laser channel; 102. Photosensitive cavity; 103. First light extinction hole; 104. Second light extinction hole; 105. Third light extinction hole; 106. Light absorption thread; 107. Bolt hole; 108. Air intake channel; 109. Exhaust channel; 1041. Installation section; 1042. Light absorption section. Specific embodiments

[0039] Next, in combination with the specific embodiments of the present utility model, the technical solutions in the present utility model will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments in the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present utility model.

[0040] As Figures 1-4 shown, a particle counting sensor of the present utility model includes an outer shell 1, a laser emitter 2 and a photoelectric receiving converter 3.

[0041] Among them, as Figure 3 shown, a laser channel 101 and a photosensitive cavity 102 are provided on the outer shell 1. One end of the laser channel 101 is communicated with the photosensitive cavity 102, and the other end is used to fix the laser emitter 2. The photoelectric receiving converter 3 is fixed on the outer shell 1, and the receiving end of the photoelectric receiving converter 3 is arranged in the photosensitive cavity 102.

[0042] The laser emitter 2 is a high-power semiconductor laser. After the laser emitter 2 emits a laser beam, the laser beam passes through the laser channel 101 and reaches the photosensitive cavity 102. In the prior art, the photosensitive cavity 102 is also called the photosensitive area. For example, in the optical path system of a particle counting sensor disclosed in CN218445045U, the photosensitive area in the system is equivalent to the photosensitive cavity 102 in this embodiment. A reflecting mirror is fixed in the photosensitive cavity 102. The reflecting mirror is used to collect the heat dissipation light and converge it on the silicon photodiode. The silicon photodiode is the receiving end of the photoelectric receiving converter 3. It is arranged in the photosensitive cavity 102 and is arranged opposite to the reflecting mirror. When the sampling air flow is irradiated by the laser beam, a light scattering phenomenon occurs. The photoelectric receiving converter 3 receives these scattered lights and converts them into electrical signals. According to the intensity and angle of the scattered lights, the size and number of particulate matters can be calculated. The specific principle can be known in the prior art and will not be elaborated in this embodiment.

[0043] Normally, after the laser of a high-power semiconductor laser is emitted, a lot of stray light will appear around the light beam. If the stray light easily enters the photosensitive cavity 102, it will affect the measurement accuracy. For this reason, a first extinction hole 103 is radially provided on the side of the laser channel 101. The inner diameter of the first extinction hole 103 is larger than the inner diameter of the laser channel 101. When the laser emitter 2 is illuminated, the stray light emitted by the laser beam is reflected back and forth in the second extinction hole 103 to consume energy to achieve extinction. At the same time, the hole wall of the laser channel 101 is dark oxidized to absorb the stray light. The two cooperate to eliminate the stray light, thereby making it difficult for the stray light to mix into the photosensitive cavity 102, thereby improving the measurement accuracy.

[0044] At the same time, in order to prevent the laser beam from irradiating the cavity wall of the photosensitive cavity 102 and causing light reflection, a second extinction hole 104 is provided on the side of the photosensitive cavity 102 away from the laser channel 101, wherein the second extinction hole 104 is connected to the photosensitive cavity 102, and the inner surface of the second extinction hole 104 is dark oxidized, and the second extinction hole 104 is coaxially arranged with the laser channel 101. When the laser beam irradiates the sampling airflow, the excess laser beam is shot into the second extinction hole 104, which prevents the laser beam from directly irradiating the cavity wall of the photosensitive cavity 102 and causing reflection, thereby helping to improve the measurement accuracy.

[0045] In the above structure, the laser channel 101, the photosensitive cavity 102, the first extinction hole 103 and the second extinction hole 104 are all set to be circular hole shapes, wherein both ends of the laser channel 101 are in the shape of stepped holes, and at least two first extinction holes 103 are set along the axial direction of the laser channel 101. This structure is used to improve the absorption effect of stray light.

[0046] In the particle counting sensor, the housing 1 is further provided with a third extinction hole 105 in the shape of a circular hole, wherein Figure 3 As shown, the third extinction hole 105 is parallel to the first extinction hole 103, and the third extinction hole 105 passes through the second extinction hole 104, and the aperture of the third extinction hole 105 is larger than the aperture of the second extinction hole 104; the aperture of the second extinction hole 104 is larger than the aperture of the laser channel 101. This structure allows the laser beam to smoothly enter the second extinction hole 104. At the same time, due to the difference in apertures, stray light can be well absorbed.

[0047] In order to prevent the laser beam from being reflected and affecting the measurement accuracy, and to improve the extinction effect, a light absorbing mechanism 4 is provided in the second extinction hole 104. Specifically, Figure 3As shown in the figure, the second light extinction hole 104 forms an installation section 1041 and a light absorption section 1042 through the third light extinction hole 105. The aperture of the installation section 1041 is larger than that of the light absorption section 1042. The light absorption mechanism 4 is fixed in the installation section 1041. The aperture of the end of the light absorption section 1042 close to the third light extinction hole 105 is larger than that of the other end. A light absorption thread 106 is provided on the hole wall of the end of the light absorption section 1042 close to the third light extinction hole 105. In this structure, the laser beam is absorbed by the light absorption mechanism 4 to eliminate the laser and prevent laser reflection. At the same time, stray light is absorbed through the light absorption thread 106 and the third light extinction hole 105, improving the light extinction effect.

[0048] In the above structure, a light absorption groove is provided inside the light absorption mechanism 4, and the inner surface of the light absorption groove is subjected to dark oxidation treatment. In addition, the light absorption mechanism 4 is fixed to the housing 1 by screws. Specifically, as Figure 3 shown, a bolt hole 107 is provided on the housing 1 at the position corresponding to the light absorption mechanism 4. The bolt hole 107 communicates with the installation section 1041. Among them, the second light extinction hole 104 is a through hole. When the light absorption mechanism 4 is inserted from one end of the second light extinction hole 104, a screw is installed in the bolt hole 107. After tightening the screw, the light absorption mechanism 4 is tightened by the screw to fix the light absorption mechanism 4 in the second light extinction hole 104.

[0049] In this particle counting sensor, an air inlet channel 108 and an air outlet channel 109 are provided on the housing 1. Among them, the air inlet channel 108 is used for the input of the sampling air flow, and the air outlet channel 109 is used for the output of the sampling air flow. Specifically, as Figure 3 shown, the air inlet channel 108 is provided on one side of the laser channel 101 and is perpendicular to the laser channel 101. The air outlet channel 109 is provided on the other side of the laser channel 101 and is perpendicular to the laser channel 101. At the same time, the air inlet channel 108 and the air outlet channel 109 are coaxially arranged, and both the air inlet channel 108 and the air outlet channel 109 communicate with the photosensitive cavity 102.

[0050] In addition, as Figure 4 shown, one end of the laser channel 101 adjacent to the air inlet channel 108 extends into the photosensitive cavity 102. The side of the end of the air inlet channel 108 extending into the photosensitive cavity 102 abuts against the side of the end of the laser channel 101 extending into the photosensitive cavity 102. In this structure, one end of the air inlet channel 108 is close to the laser channel 101. Therefore, the input sampling air flow will be irradiated by the laser beam immediately and cause the phenomenon of light scattering, which is beneficial to improving the measurement accuracy.

[0051] In addition, as Figure 4 shown, one end of the first light extinction hole 103, the photosensitive cavity 102, and the third light extinction hole 105 all penetrate one end of the housing 1 to form a counterbore-like structure. In order to seal the counterbore-like structure, as Figure 1As shown, a cover plate is provided at this structure to enclose the sunken hole-shaped structure. The cover plate is fixed to the housing 1 by screws, which is convenient for disassembly.

[0052] A method for using a particle counting sensor of the present utility model is as follows:

[0053] First, the sampling air flow is input into the photosensitive cavity 102 from the air inlet channel 108, and then output from the exhaust channel 109. The laser emitter 2 emits a laser beam in the direction of the light absorption mechanism 4. The laser beam passes straight through the laser channel 101. During this process, the hole wall of the laser channel 101 and the first extinction hole 103 absorb the stray light generated by the laser beam itself. When the laser beam with the stray light removed reaches the photosensitive cavity 102, it irradiates the sampling air flow. After that, the laser beam passes through the second extinction hole 104 and then falls into the light absorption mechanism 4 to be extinguished.

[0054] The above are only the preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present utility model shall be included in the protection scope of the present utility model.

Claims

1. A particle counting sensor, comprising a housing (1), a laser emitter (2) and a photoelectric receiving converter (3), wherein, a laser channel (101) and a photosensitive cavity (102) are provided on the housing (1), one end of the laser channel (101) communicates with the photosensitive cavity (102), and the other end is used to fix the laser emitter (2); the photoelectric receiving converter (3) is fixed on the housing (1), and the receiving end of the photoelectric receiving converter (3) is arranged in the photosensitive cavity (102); characterized in that: a first extinction hole (103) is provided through the side of the laser channel (101) in the radial direction, and the inner diameter of the first extinction hole (103) is larger than the inner diameter of the laser channel (101); a second extinction hole (104) is provided on one side of the photosensitive cavity (102) away from the laser channel (101), the second extinction hole (104) communicates with the photosensitive cavity (102), and the second extinction hole (104) is coaxially arranged with the laser channel (101).

2. The particle counting sensor according to claim 1, wherein: The laser channel (101), the photosensitive cavity (102), the first extinction hole (103) and the second extinction hole (104) are all in the shape of a circular hole.

3. A particle counting sensor according to claim 1, characterized in that: Both ends of the laser channel (101) are in the shape of a stepped hole.

4. The particle counting sensor according to claim 1, wherein: At least two first extinction holes (103) are arranged along the axial direction of the laser channel (101).

5. A particle counting sensor according to claim 1, characterized in that: A third extinction hole (105) is provided on the housing (1), the third extinction hole (105) is parallel to the first extinction hole (103), and the third extinction hole (105) penetrates through the second extinction hole (104), wherein, the aperture of the third extinction hole (105) is larger than the aperture of the second extinction hole (104).

6. The particle counting sensor according to claim 5, characterized in that: The aperture of the second extinction hole (104) is larger than the aperture of the laser channel (101).

7. The particle counting sensor according to claim 6, wherein: It further comprises a light absorption mechanism (4), wherein, the second extinction hole (104) forms an installation section (1041) and a light absorption section (1042) through the third extinction hole (105), and the aperture of the installation section (1041) is larger than the aperture of the light absorption section (1042); the light absorption mechanism (4) is fixed in the installation section (1041); the aperture of one end of the light absorption section (1042) close to the third extinction hole (105) is larger than that of the other end, and a light absorption thread (106) is provided on the hole wall of the end of the light absorption section (1042) close to the third extinction hole (105).

8. A particle counting sensor according to claim 7, characterized in that: A bolt hole (107) is provided on the housing (1) at a position corresponding to the light absorption mechanism (4), and the bolt hole (107) communicates with the installation section (1041).

9. The particle counting sensor according to claim 1, wherein: An air inlet channel (108) and an air exhaust channel (109) are provided on the housing (1), wherein, the air inlet channel (108) is arranged on one side of the laser channel (101) and perpendicular to the laser channel (101), and the air exhaust channel (109) is arranged on the other side of the laser channel (101) and perpendicular to the laser channel (101); The intake passage (108) and the exhaust passage (109) are coaxially arranged; Both the intake passage (108) and the exhaust passage (109) communicate with the photosensitive cavity (102).

10. A particle counting sensor according to claim 9, characterized in that: One end of the laser passage (101) adjacent to the intake passage (108) extends into the photosensitive cavity (102).

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