Particle detection device and detection method
By setting a mirror in the detection cavity of the particle detection device, multiple reflections and focusing of light are achieved, and the problem of increasing the power of the laser when detecting tiny particles in the prior art is solved, and the equipment is miniaturized and high-precision detection is realized.
Patent Information
- Application Number
- CN202411902549.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-23
- Publication Date
- 2025-02-25
AI Technical Summary
When detecting tiny particles, existing particle detection methods need to increase the laser power to improve detection sensitivity, but this leads to increased equipment costs, serious heat dissipation problems and increased equipment volume, which is not conducive to miniaturization applications.
By providing a reflector in the detection cavity, multiple reflections of light and focusing on the center position of the detection cavity are achieved, thereby forming a high-intensity laser area at the intersection of the optical path and the gas path, improving detection accuracy and sensitivity.
It reduces the power of the laser equipment, reduces the light source volume and power consumption, improves the overall performance of the sensor, facilitates the miniaturization of the equipment, and realizes high-precision detection of micro particles.
Smart Images
Figure CN119510237A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of particle detection, and in particular to a particle detection device and a particle detection method. Background Art
[0002] With the advancement of science and technology, especially the development of semiconductor and other industries, the requirements for cleanliness of industrial production environment, experimental space environment, etc. are getting higher and higher, and the demand for detection of extremely small particles is also getting higher and higher. The existing detection methods are mainly based on Mie scattering laser particle counters, that is, the laser as a light source enters the detection cavity after focusing and collimating lenses, and the light path and gas path in the detection cavity converge at one point, which is also the focal position of the laser convergence, and the collecting light reflector collects the collected particle scattered light on the collecting light lens (the unscattered light is absorbed by the inner wall of the detection cavity or the extinction trap), and then after photoelectric conversion and signal processing, it becomes a pulse signal corresponding to the particle size, thereby completing the detection. The defect of this method is that the laser power is used once. When the particles are very small, the detection sensitivity can only be improved by increasing the laser power, which will greatly increase the purchase cost of the laser. At the same time, the greater the laser power, the heat dissipation problem is also an important factor to be considered by the system. Moreover, as the laser power increases, the volume will inevitably increase, which is not conducive to the miniaturization of the equipment. Summary of the invention
[0003] The object of the present invention is to overcome one or more deficiencies in the prior art and to provide an improved particle detection device that can at least solve one problem in the background art.
[0004] The present invention also provides a particle detection method, which can detect smaller particles with smaller laser power.
[0005] In order to achieve the above object, a technical solution adopted by the present invention is: a particle detection device, the detection device comprising:
[0006] A detection cavity, an air inlet nozzle and an air outlet nozzle arranged on the detection cavity, wherein an air path formed between the air inlet nozzle and the air outlet nozzle passes through the center position of the detection cavity;
[0007] A light source assembly capable of providing light focused at the center of the detection cavity;
[0008] A first reflector and a second reflector, wherein the first reflector and the second reflector are at least used to converge the reflected light at the center of the detection cavity, and the first reflector and the second reflector are arranged at two opposite sides of the center of the detection cavity;
[0009] A light collecting reflector and a light receiving lens, wherein the convergence focus of the light collecting reflector is located on the light receiving lens, and the light collecting reflector and the light receiving lens are arranged on opposite sides of the center position of the detection cavity.
[0010] According to some preferred aspects of the present invention, the distance between the air outlet of the air inlet nozzle and the center position of the detection cavity is less than or equal to 2 mm.
[0011] In some preferred embodiments of the present invention, the first reflector and the second reflector are arranged opposite to each other along a first direction, the light collecting reflector and the light receiving lens are arranged opposite to each other along a second direction, and the first direction intersects with the second direction.
[0012] In some preferred embodiments of the present invention, the first direction is perpendicular to the second direction.
[0013] In some preferred embodiments of the present invention, the first direction is the same as the light path of the light provided by the light source assembly.
[0014] In some preferred embodiments of the present invention, the light source assembly includes a light source, a focusing lens and a one-way lens, and the light source, the focusing lens and the one-way lens are arranged in sequence along the same direction.
[0015] Furthermore, the light source is a laser, for example, a semiconductor laser.
[0016] In some preferred embodiments of the present invention, the one-way lens is disposed on the second reflector and partially passes through the second reflector.
[0017] In some embodiments of the present invention, the first reflector and the second reflector are located on the left and right sides of the detection cavity, the collecting light reflector is located at the rear of the detection cavity, the receiving light lens is located at the front of the detection cavity, the air inlet nozzle is located at the top of the detection cavity, and the air outlet nozzle is located at the bottom of the detection cavity.
[0018] In some embodiments of the present invention, the left side wall of the detection cavity is formed by the second reflector, the right side wall of the detection cavity is formed by the first reflector, and the rear of the detection cavity is formed by the light collecting reflector.
[0019] Another technical solution provided by the present invention is a method for detecting particles, the method comprising a particle size and / or quantity detection process, the particle size and / or quantity detection process comprising:
[0020] Providing a detection cavity;
[0021] Providing light that can be focused on the center of the detection cavity so that the gas path passes through the center of the detection cavity;
[0022] The light in the detection cavity is reflected multiple times by a reflector, and is focused at the center of the detection cavity after each reflection;
[0023] The reflected light is collected by a light collecting mirror and converged on a light receiving lens, and then a pulse signal related to the particle size is formed through signal processing.
[0024] According to some specific aspects of the present invention, the optical power of the provided light is P, the reflection efficiency of the reflector is η, and the optical power at the center of the detection cavity after n reflections is P0, which satisfies the following conditions:
[0025] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:
[0026] Based on the problem that the laser power in the prior art needs to be increased simultaneously when detecting tiny particles, which leads to problems such as equipment cost, heat dissipation, and large size, the inventors of the present invention innovatively use a reflector to reflect the laser light in the cavity multiple times, forming a high-intensity laser area at the intersection of the light path and the gas path, thereby improving detection accuracy and sensitivity. Such a design can greatly reduce the power of the laser equipment, reduce the size of the light source, reduce the power consumption of the light source, reduce the overall size of the sensor, improve the overall performance of the sensor, facilitate the miniaturization of the equipment, and enable high-precision detection of tiny particles. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.
[0028] Figure 1 Schematic diagram of the structure of a particle detection device in an embodiment of the present invention (viewing angle 1);
[0029] Figure 2 Schematic diagram of the structure of the particle detection device in the embodiment of the present invention (viewing angle 2);
[0030] Figure 3 is a principle block diagram of a conversion circuit used in an embodiment of the present invention;
[0031] In the accompanying drawings: 101, receiving light lens; 102, first reflector; 103, second reflector; 104, laser; 105, focusing lens; 106, one-way lens; 107, collecting light reflector; 108, detection cavity; 201, air inlet nozzle; 202, particulate matter; 203, air outlet nozzle. DETAILED DESCRIPTION
[0032] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.
[0033] In the description of the present invention, “plurality” means at least two, for example, two, three, etc., unless otherwise clearly and specifically defined.
[0034] The preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings.
[0035] See also Figures 1 to 3 As shown, this example provides a particle detection device, which includes a detection cavity 108, an air inlet nozzle 201 and an air outlet nozzle 202 arranged on the detection cavity 108, a light source assembly, a first reflector 102, a second reflector 103, a light collecting reflector 107 and a light receiving lens 101.
[0036] in, Figure 1 A schematic cross-sectional bottom view of a particle detection device is given as an example. Figure 2 A front cross-sectional schematic diagram of a particle detection device is given as an example, Figure 3 The circuit principle block diagram of optical signal conversion is given as an example.
[0037] In this example, the air path formed between the air inlet nozzle 201 and the air outlet nozzle 202 passes through the center position of the detection cavity 108. The air flow enters from the air inlet nozzle 201, passes through the center position of the detection cavity 108, and flows out from the air outlet nozzle 203; further, the center position of the detection cavity 108 and the air flow outlet position of the air inlet nozzle 201 cannot be too far, preferably less than 5 mm, and can be further set to be less than or equal to 2 mm.
[0038] The light source assembly can provide light focused on the center position of the detection cavity 108. Furthermore, in this example, the light source assembly includes a light source, a focusing lens 105 and a one-way lens 106, and the light source, the focusing lens 105 and the one-way lens 106 are arranged in sequence along the same direction; the light source is a laser 104, for example, it can be a semiconductor laser, and the one-way lens 106 is arranged on the second reflector 103 and partially passes through the second reflector 103.
[0039] The first reflector 102 and the second reflector 103 are at least used to converge the reflected light at the center of the detection cavity 108, and the first reflector 102 and the second reflector 103 are arranged on opposite sides of the center of the detection cavity 108; the convergence focus of the light collecting reflector 107 is located on the light receiving lens 101, and the light collecting reflector 107 and the light receiving lens 101 are arranged on opposite sides of the center of the detection cavity 108. Further, in this example, the first reflector 102 and the second reflector 103 are arranged opposite to each other along a first direction, and the light collecting reflector 107 and the light receiving lens 101 are arranged opposite to each other along a second direction, the first direction intersects with the second direction, for example, they can be perpendicular to each other, and the first direction is in the same direction as the optical path of the light provided by the light source assembly.
[0040] In this example, the first reflector 102 and the second reflector 103 are located on the left and right sides of the detection cavity 108, the collecting light reflector 107 is located at the rear of the detection cavity 108, the receiving light lens 101 is located at the front of the detection cavity 108, the air inlet nozzle 201 is located at the top of the detection cavity 108, and the air outlet nozzle 203 is located at the bottom of the detection cavity 108.
[0041] In other embodiments, the left side wall of the detection cavity 108 is formed by the second reflector 103 , the right side wall of the detection cavity 108 is formed by the first reflector 102 , and the rear of the detection cavity 108 is formed by the light collecting reflector 107 .
[0042] This example also provides a particle detection method, which includes a particle size and / or quantity detection process, and the particle size and / or quantity detection process includes:
[0043] Providing a detection cavity;
[0044] Providing light that can be focused on the center of the detection cavity so that the gas path passes through the center of the detection cavity;
[0045] The light in the detection cavity is reflected multiple times by the reflector, and each reflection is focused on the center of the detection cavity;
[0046] The reflected light is collected by a light collecting mirror and converged on a light receiving lens, and then a pulse signal related to the particle size is formed through signal processing.
[0047] Furthermore, the optical power of the provided light is P, the reflection efficiency of the reflector is η, and the optical power at the center of the detection cavity after n reflections is P0, which satisfies the following conditions:
[0048] The process and principle of the particle detection device and detection method of this example are roughly as follows:
[0049] The laser light generated by the laser 104 passes through the focusing lens 105 and the one-way lens 106 and converges at the center of the detection cavity 108. The center position cannot be too far from the air inlet nozzle 201 (the distance can be set to be less than 2 mm). At the same time, the convergence focus of the first reflector 102 and the second reflector 103 is also at the center position. When there is no particle passing, the laser light will be irradiated onto the first reflector 102. The first reflector 102 reflects the laser light and converges it at the center of the detection cavity 108, and then further irradiates it onto the second reflector 103. It is reflected multiple times in sequence and still converges at the center of the detection cavity. Assuming that the laser power is P and the reflection efficiency of the reflector is η, the laser power at the focal position after n reflections can reach: P0 = (P × (1-η n )) / (1-η); It can be seen that the optical power at the center of the detection cavity depends on the reflectivity of the reflector. The higher the reflectivity, the higher the optical power at the center, and its multiple is approximately 1 / (1-η).
[0050] When particles 202 enter the center of the detection cavity, the intensity of the scattered light from the particles will be greatly increased, and the scattered light intensity of the same particles will be magnified several times. The scattered light is converged on the receiving light lens 101 through the collecting light reflector 107, and then converged on the photoelectric detection device, photoelectric conversion circuit, signal processing circuit, etc. at the rear end through the receiving light lens 101, and finally a pulse signal related to the particle size is formed, thereby finally achieving the identification and counting of the particle size.
[0051] Further, see Figure 3 As shown, it exemplarily gives a circuit principle block diagram of optical signal conversion. The optical signal collected by the light collecting lens is converted into a current signal by the photodetector, and then converted into a voltage signal at the preamplifier, and then processed by the filter circuit for noise removal, and then isolated at the follower and output a signal to the comparator, where it is compared with the threshold voltage. If it is higher than the threshold voltage, a high level is output, and if it is lower than the threshold voltage, a low level is output. The output electrical signal is then received by the counter, thereby realizing the detection of particle size and / or quantity; by setting multiple comparators, the detection of more particle sizes can be realized.
[0052] In summary, the present invention uses a laser to generate light for detection, which is converged at the center of the detection cavity after passing through a focusing lens 105 and a one-way lens 106. Two reflectors reflect the original laser light and focus it at the center of the detection cavity, thereby forming a high-intensity light density in the center of the detection cavity. When particles pass through, their scattering phenomenon will occur multiple times on the particles, thereby achieving that small particles can also generate a large scattered light flux. The light collecting reflector is used to converge the scattered light scattered by the small particles onto the receiving light lens, and then the collected scattered light is gathered to the photoelectric conversion device and the signal processing circuit to convert it into a recognizable voltage signal, thereby achieving the identification and counting of the particle size of small particles.
[0053] The present invention innovatively adopts the establishment of a multiple reflection cavity to enhance the scattered light intensity of tiny particles, realizes the detection of particles with smaller particle sizes under the same light source power, and improves the detection accuracy and sensitivity. Such a design can greatly reduce the power of the laser equipment, reduce the size of the light source, reduce the power consumption of the light source, reduce the overall size of the sensor, improve the overall performance of the sensor, facilitate the miniaturization of the equipment, and can perform high-precision detection of tiny particles.
[0054] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the contents of the present invention and implement them accordingly. They cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.
Claims
1. A particle detection device, characterized in that: The detection device comprises: A detection cavity, an air inlet nozzle and an air outlet nozzle arranged on the detection cavity, wherein an air path formed between the air inlet nozzle and the air outlet nozzle passes through the center position of the detection cavity; A light source assembly capable of providing light focused at the center of the detection cavity; A first reflector and a second reflector, wherein the first reflector and the second reflector are at least used to converge the reflected light at the center of the detection cavity, and the first reflector and the second reflector are arranged at two opposite sides of the center of the detection cavity; A light collecting reflector and a light receiving lens, wherein the convergence focus of the light collecting reflector is located on the light receiving lens, and the light collecting reflector and the light receiving lens are arranged on opposite sides of the center position of the detection cavity.
2. The particle detection device according to claim 1, characterized in that: The distance between the air outlet of the air inlet nozzle and the center position of the detection cavity is less than or equal to 2 mm.
3. The particle detection device according to claim 1, characterized in that: The first reflector and the second reflector are arranged opposite to each other along a first direction, the light collecting reflector and the light receiving lens are arranged opposite to each other along a second direction, and the first direction intersects with the second direction.
4. The particle detection device according to claim 3, characterized in that: The first direction is perpendicular to the second direction; and / or the first direction is in the same direction as the light path of the light provided by the light source assembly.
5. The particle detection device according to claim 1, characterized in that: The light source assembly comprises a light source, a condenser lens and a one-way lens, and the light source, the condenser lens and the one-way lens are arranged in sequence along the same direction.
6. The particle detection device according to claim 5, characterized in that: The light source is a laser; and / or the one-way lens is disposed on the second reflector and partially passes through the second reflector.
7. The particle detection device according to claim 1, characterized in that: The first reflector and the second reflector are located at the left and right sides of the detection cavity, the light collecting reflector is located at the rear of the detection cavity, the light receiving lens is located at the front of the detection cavity, the air inlet nozzle is located at the top of the detection cavity, and the air outlet nozzle is located at the bottom of the detection cavity.
8. The particle detection device according to claim 1, characterized in that: The left side wall of the detection cavity is formed by the second reflector, the right side wall of the detection cavity is formed by the first reflector, and the rear part of the detection cavity is formed by the light collecting reflector.
9. A method for detecting particles, characterized in that: The particle detection method includes a particle size and / or quantity detection process, and the particle size and / or quantity detection process includes: Providing a detection cavity; Providing light that can be focused on the center of the detection cavity so that the gas path passes through the center of the detection cavity; The light in the detection cavity is reflected multiple times by a reflector, and is focused at the center of the detection cavity after each reflection; The reflected light is collected by a light collecting mirror and converged on a light receiving lens, and then a pulse signal related to the particle size is formed through signal processing.
10. The particle detection method according to claim 9, characterized in that: The optical power of the light provided is P, the reflection efficiency of the reflector is η, and the optical power at the center of the detection cavity after n reflections is P0, which satisfies the following conditions: