Particle detection device
By employing a multi-mirror design in the particle detection device, the detection accuracy and sensitivity of tiny particles are improved, solving the problems of high cost and large size caused by the increase of laser power in the prior art, and realizing the miniaturization of the equipment.
Patent Information
- Application Number
- CN202423186604.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-23
- Publication Date
- 2026-02-03
- Estimated Expiration
- 2034-12-23
AI Technical Summary
In existing technologies, laser power needs to be increased to improve detection sensitivity, resulting in high equipment costs, serious heat dissipation problems, and hindering miniaturization.
By using a reflector to reflect the laser beam multiple times within the cavity, a high-intensity laser region is formed at the intersection of the optical path and the gas path, improving detection accuracy and sensitivity while reducing laser power and size.
It enables high-precision detection of tiny particles, reduces laser equipment power, shrinks the size and power consumption of the light source, and promotes the miniaturization of the equipment.
Smart Images
Figure CN223870492U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of particle detection technology, and specifically to a particle detection device. Background Technology
[0002] With the advancement of technology, especially the development of industries such as semiconductors, the requirements for cleanliness in industrial production environments and experimental spaces are becoming increasingly stringent, as is the demand for the detection of extremely small particles. Current detection methods primarily rely on laser particle counters based on Mie scattering. In this method, a laser, acting as the light source, enters the detection cavity after being focused and collimated by a lens. The optical path and gas path within the detection cavity converge at a single point, which is also the focal point of the laser. A collecting mirror then focuses the scattered light from the particles onto a collecting lens (unscattered light is absorbed by the inner wall of the detection cavity or by extinction traps). This light is then converted into a pulse signal corresponding to the particle size after photoelectric conversion and signal processing, thus completing the detection. The drawbacks of this method are that the laser power is limited to a single use. When the particles are extremely small, increasing the detection sensitivity requires increasing the laser power, which significantly increases the purchase cost. Furthermore, higher laser power raises concerns about heat dissipation, and the increased laser power inevitably leads to a larger size, hindering the miniaturization of the equipment. Utility Model Content
[0003] The purpose of this invention is to overcome one or more deficiencies in the prior art and provide an improved particle detection device that can at least solve one problem in the background art.
[0004] To achieve the above objectives, the technical solution adopted by this utility model is as follows:
[0005] A particle detection device, the detection device comprising:
[0006] The detection chamber, the air inlet and the air outlet are provided on the detection chamber, and the air path formed between the air inlet and the air outlet passes through the center of the detection chamber.
[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, both of which are used to converge the reflected light to the center of the detection cavity, and the first reflector and the second reflector are arranged on opposite sides of the center of the detection cavity;
[0009] The light-collecting mirror and the light-receiving lens are arranged on opposite sides of the center of the detection cavity. The light-collecting mirror has its focal point located on the light-receiving lens.
[0010] According to some preferred aspects of this utility model, the distance between the air outlet of the air inlet and the center position of the detection cavity is less than or equal to 2 mm.
[0011] In some preferred embodiments of this utility model, the first reflector and the second reflector are arranged opposite to each other along a first direction, and the light-collecting reflector and the light-receiving lens are arranged opposite to each other along a second direction, wherein the first direction and the second direction intersect.
[0012] In some preferred embodiments of this utility model, the first direction is perpendicular to the second direction.
[0013] In some preferred embodiments of this invention, the first direction is in the same direction as the light path of the light provided by the light source assembly.
[0014] In some preferred embodiments of this utility model, the light source assembly includes 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 sequentially along the same direction.
[0015] Furthermore, the light source is a laser, for example, a semiconductor laser.
[0016] In some preferred embodiments of this invention, the one-way lens is disposed on the second reflector and partially passes through the second reflector.
[0017] In some embodiments of this utility model, the first reflector and the second reflector are located on 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 is located at the top of the detection cavity, and the air outlet is located at the bottom of the detection cavity.
[0018] In some embodiments of this utility model, 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.
[0019] Due to the application of the above technical solution, this utility model has the following advantages compared with the prior art:
[0020] Addressing the issues of increased laser power, leading to higher equipment costs, heat dissipation, and excessive size in existing technologies for detecting minute particles, this invention innovatively employs a reflector to reflect the laser beam multiple times within the cavity, creating a high-intensity laser region at the intersection of the optical and gas paths. This improves detection accuracy and sensitivity. Such a design significantly reduces laser power, shrinks the light source size and power consumption, reduces the overall sensor size, and enhances overall sensor performance. This facilitates equipment miniaturization and enables high-precision detection of minute particles. Attached Figure Description
[0021] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0022] Figure 1 This is a schematic diagram of the particle detection device in an embodiment of the present invention (view 1);
[0023] Figure 2 This is a schematic diagram of the particle detection device in an embodiment of the present invention (perspective two);
[0024] Figure 3 This is a schematic block diagram of the conversion circuit used in the embodiments of this utility model;
[0025] In the attached figures: 101, receiving lens; 102, first reflecting mirror; 103, second reflecting mirror; 104, laser; 105, focusing lens; 106, one-way lens; 107, collecting mirror; 108, detection cavity; 201, air inlet; 202, particulate matter; 203, air outlet. Detailed Implementation
[0026] To make the above-mentioned objects, features, and advantages of this utility model more apparent and understandable, the present utility model will be described in detail below with reference to the accompanying drawings and specific embodiments. Many specific details are set forth in the following description to provide a full understanding of the present utility model. However, the present utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present utility model. Therefore, the present utility model is not limited to the specific embodiments disclosed below.
[0027] In the description of this utility model, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.
[0028] The preferred embodiments of this utility model will now be described in detail with reference to the accompanying drawings.
[0029] See Figures 1 to 3 As shown, this example provides a particle detection device, which includes a detection chamber 108, an air inlet 201 and an air outlet 202 disposed on the detection chamber 108, a light source assembly, a first reflector 102, a second reflector 103, a light collecting reflector 107, and a light receiving lens 101.
[0030] in, Figure 1 An exemplary bottom cross-sectional view of a particle detection device is provided. Figure 2 An exemplary front cross-sectional view of a particle detection device is provided. Figure 3 An exemplary circuit block diagram for optical signal conversion is provided.
[0031] In this example, the air path formed between the air inlet 201 and the air outlet 202 passes through the center of the detection chamber 108. The airflow enters from the air inlet 201, passes through the center of the detection chamber 108, and flows out from the air outlet 203. Furthermore, the center of the detection chamber 108 and the air outlet of the air inlet 201 should not be too far apart, preferably less than 5 mm, and can be further set to less than or equal to 2 mm.
[0032] The light source assembly can provide light focused on the center position of the detection cavity 108. Further, in this example, the light source assembly includes a light source, a condenser lens 105 and a one-way lens 106, which are arranged sequentially along the same direction. The light source is a laser 104, such as a semiconductor laser. The one-way lens 106 is disposed on the second reflector 103 and partially passes through the second reflector 103.
[0033] Both the first reflecting mirror 102 and the second reflecting mirror 103 are used to converge the reflected light to the center of the detection cavity 108. The first reflecting mirror 102 and the second reflecting mirror 103 are arranged on opposite sides of the center of the detection cavity 108. The focusing point of the light collecting mirror 107 is located on the light receiving lens 101. The light collecting mirror 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 reflecting mirror 102 and the second reflecting mirror 103 are arranged opposite each other along a first direction, and the light collecting mirror 107 and the light receiving lens 101 are arranged opposite each other along a second direction. The first direction and the second direction intersect, for example, they can be perpendicular. The first direction is in the same direction as the light path provided by the light source assembly.
[0034] 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 light collecting reflector 107 is located at the rear of the detection cavity 108, the light receiving lens 101 is located at the front of the detection cavity 108, the air inlet 201 is located at the top of the detection cavity 108, and the air outlet 203 is located at the bottom of the detection cavity 108.
[0035] In other embodiments, the left side wall of the detection cavity 108 is formed by a second reflector 103, the right side wall of the detection cavity 108 is formed by a first reflector 102, and the rear part of the detection cavity 108 is formed by a light-collecting reflector 107.
[0036] This example also provides a method for detecting particles, which includes a step of detecting particle size and / or quantity. The step of detecting particle size and / or quantity includes:
[0037] Provide a detection chamber;
[0038] Provides light that can be focused on the center of the detection chamber, allowing the gas path to pass through the center of the detection chamber;
[0039] The light inside the detection cavity is reflected multiple times by a mirror, and after each reflection, it is focused on the center of the detection cavity.
[0040] The reflected light is collected by a light-collecting mirror and then focused onto a light-receiving lens. The light is then processed to form a pulse signal related to the particle size.
[0041] Furthermore, let the optical power of the provided light be P, the reflection efficiency of the mirror be denoted as η, and the optical power at the center position of the detection cavity after n reflections be P0, satisfying the following condition:
[0042] The process and principle of the particle detection device and method in this example are roughly as follows:
[0043] The laser beam generated by laser 104 is focused at the center of detection cavity 108 after passing through focusing lens 105 and one-way lens 106. This center is not too far from the air inlet 201 (the distance can be set to less than 2mm). Simultaneously, the focal points of the first reflecting mirror 102 and the second reflecting mirror 103 are also at this center. When no particles pass through, the laser beam will illuminate the first reflecting mirror 102, which reflects and focuses the laser beam at the center of detection cavity 108, further illuminating the second reflecting mirror 103. This process repeats multiple times, with the beam still converging at the center of the detection cavity. Assuming the laser power is P and the reflection efficiency of the reflecting mirrors is η, the laser power at the focal point after n reflections can reach: P0 = (P × (1 - η)) / (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 mirror. The higher the reflectivity, the higher the optical power at the center, and the multiple is about 1 / (1-η).
[0044] When a particle 202 enters the center of the detection cavity, the intensity of the scattered light from the particle will be greatly increased, and the intensity of the scattered light from the same particle will be amplified several times. The scattered light is focused by the light-collecting reflector 107 onto the light-receiving lens 101, and then focused by the light-receiving lens 101 onto the photoelectric detection device, photoelectric conversion circuit, signal processing circuit, etc. at the rear end, finally forming a pulse signal related to the particle size, and finally achieving the identification and counting of particle size.
[0045] Further, see Figure 3 As shown, an exemplary circuit block diagram of optical signal conversion is provided. The optical signal collected by the optical lens is converted into a current signal by the photodetector, then converted into a voltage signal by the preamplifier, then processed by the filtering circuit for noise reduction, then isolated by the follower and output as a signal to the comparator. The comparator compares the signal with a threshold voltage. If the voltage is higher than the threshold voltage, a high level is output; if the voltage 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 achieved.
[0046] In summary, this invention uses a laser to generate light for detection, which is then focused at the center of the detection cavity by 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, thus creating a high-intensity light density at the center. When particles pass through, scattering occurs multiple times on the particles, allowing even tiny particles to generate a large amount of scattered light flux. The light-collecting reflector is used to focus the scattered light from the tiny particles onto the receiving lens, and then the collected scattered light is focused onto a photoelectric conversion device and signal processing circuit to convert it into a recognizable voltage signal, thereby achieving the discrimination and counting of tiny particle sizes.
[0047] This invention innovatively employs a multi-reflection cavity to enhance the intensity of scattered light from tiny particles, enabling the detection of even smaller particles with the same light source power, thus improving detection accuracy and sensitivity. This design significantly reduces laser equipment power, light source size, power consumption, and overall sensor size, improving overall sensor performance and facilitating equipment miniaturization. It also enables high-precision detection of tiny particles.
[0048] The above embodiments are only for illustrating the technical concept and features of this utility model. Their purpose is to enable those skilled in the art to understand the content of this utility model and implement it accordingly. They should not be used to limit the protection scope of this utility model. All equivalent changes or modifications made in accordance with the spirit and essence of this utility model should be included within the protection scope of this utility model.
Claims
1. A particle detection device, characterized in that, The detection device includes: The detection chamber, the air inlet and the air outlet are provided on the detection chamber, and the air path formed between the air inlet and the air outlet passes through the center of the detection chamber. A light source assembly capable of providing light focused at the center of the detection cavity; A first reflector and a second reflector, both of which are used to converge the reflected light to the center of the detection cavity, and the first reflector and the second reflector are arranged on opposite sides of the center of the detection cavity; The light-collecting mirror and the light-receiving lens are arranged on opposite sides of the center of the detection cavity. The light-collecting mirror has its focal point located on the light-receiving lens.
2. The particle detection device according to claim 1, characterized in that, The distance between the air outlet of the air inlet and the center 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 each other along a first direction, and the light-collecting reflector and the light-receiving lens are arranged opposite each other along a second direction, wherein the first direction and the second direction intersect.
4. The particle detection device according to claim 3, characterized in that, The first direction is perpendicular to the second direction.
5. The particle detection device according to claim 3, characterized in that, The first direction is in the same direction as the light path provided by the light source component.
6. The particle detection device according to claim 1, characterized in that, The light source assembly includes a light source, a condenser lens, and a one-way lens, which are arranged sequentially along the same direction.
7. The particle detection device according to claim 6, characterized in that, The light source is a laser.
8. The particle detection device according to claim 6, characterized in that, The one-way lens is disposed on the second reflector and partially passes through the second reflector.
9. The particle detection device according to claim 1, characterized in that, The first reflector and the second reflector are located on 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 is located at the top of the detection cavity, and the air outlet is located at the bottom of the detection cavity.
10. 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.