Moving tin particle feature detection device

Abstract

The utility model relates to laser plasma extreme ultraviolet light source equipment technical field especially relates to a kind of moving tin microparticle feature detection device, including tin microparticle generation module, motion speed measurement module, delay shooting module and image processing analysis module.Tin microparticle generation module realizes the accurate release and vertical drop of tin microparticle by motor-driven microporous structure;Motion speed measurement module utilizes double laser photoelectric detection system to calculate particle instantaneous speed in real time, and determine synchronous shooting delay time;Delay shooting module triggers industrial camera to snap according to speed signal, obtains high-contrast profile image;Image processing analysis module extracts particle size, position offset and other characteristic parameters by algorithm.The utility model breaks through the dependence of traditional EUV tin droplet monitoring on high-cost equipment and complex environment, realizes high-precision measurement of particle motion speed, size and position under simplified experimental conditions, and provides reliable experimental support for EUV light source research.

Description

Technical Field

[0001] This utility model relates to the technical field of laser plasma extreme ultraviolet light source equipment, and in particular to a device for detecting the characteristics of moving tin particles. Background Technology

[0002] Extreme ultraviolet (EUV) light sources are core components of next-generation high-resolution micro-nano fabrication and advanced photolithography technologies, and their performance directly impacts the process precision and efficiency in fields such as semiconductor manufacturing. In existing EUV light source systems, 13.5 nm wavelength EUV light is primarily generated by bombarding tin (Sn) droplet targets with a high-energy laser: the laser energy rapidly vaporizes the tin droplets, forming a high-temperature plasma, and the highly charged tin ions release EUV radiation during de-excitation. The tin droplets, as the key medium for laser-induced plasma, have physical properties (such as size, velocity, and trajectory) and spatial matching accuracy with the laser beam that directly determine the EUV light conversion efficiency and system stability.

[0003] Currently, the generation and control of tin droplets rely on high-precision laser heating systems and complex vacuum environment control devices, which present the following technical bottlenecks: the equipment needs to be equipped with a high-stability laser, a precision motion control module, and a vacuum system, resulting in high equipment costs and complex maintenance; the high vacuum environment and ultra-cleanliness requirements limit the flexibility of scientific research and debugging, and increase the technology verification cycle; core components (such as high-power CO2 lasers and droplet generators) have long relied on imports, which has restricted the independent innovation and industrialization process of domestic EUV light source technology.

[0004] To overcome the above limitations, it is urgent to develop a low-cost, modular experimental platform that can accurately simulate the motion behavior of molten tin droplets under simplified conditions (such as atmospheric pressure) and achieve efficient detection of its key parameters (velocity, size, and position offset), thereby providing reliable data support and method verification for the optimized design of EUV light sources. Utility Model Content

[0005] This invention provides a device for detecting the characteristics of moving tin particles, which addresses the shortcomings of existing technologies where the generation and monitoring of tin droplet targets from extreme ultraviolet light sources rely on high-cost equipment and complex experimental environments. This device enables real-time detection and analysis of the characteristics of moving tin particles under simplified and controllable experimental conditions, providing reliable experimental data and technical support for the study of the generation and motion behavior of tin droplets from extreme ultraviolet light sources.

[0006] This invention provides a device for detecting the characteristics of moving tin particles, including a tin particle generation module, a motion speed measurement module, a time-lapse imaging module, and an image processing and analysis module. The tin particle generation module controls the release and vertical descent of tin particles. The motion speed measurement module is located below the tin particle generation module and is used to detect the instantaneous velocity of the falling tin particles. The time-lapse imaging module is located below the motion speed measurement module and is connected to it. The time-lapse imaging module is triggered by the motion speed measurement module and performs time-lapse capture to photograph the falling motion pattern of the tin particles. The image processing and analysis module is connected to the time-lapse imaging module. The image processing and analysis module receives the images captured by the time-lapse imaging module and analyzes the size and positional offset of the generated tin particles.

[0007] According to the present invention, a device for detecting the characteristics of moving tin particles is provided. The tin particle generation module includes a tin particle funnel, a motor, and a collimation channel tube. The tin particle funnel is inserted through a funnel base, and the funnel base is mounted on a first support frame. The output shaft of the motor is inserted through the outlet of the tin particle funnel to control the quantitative release of tin particles. The collimation channel tube is vertically connected to the outlet of the tin particle funnel to guide the tin particles to fall vertically.

[0008] According to the present invention, a device for detecting the characteristics of moving tin particles is provided, wherein the output shaft is provided with a microhole at the position corresponding to the outlet of the tin particle funnel, and the diameter of the microhole is suitable for allowing a tin particle to enter and be temporarily stored.

[0009] According to the present invention, a device for detecting the characteristics of moving tin particles is provided. The motion speed measurement module includes a first optical path detection mechanism, a second optical path detection mechanism, and a microcontroller. The first optical path detection mechanism includes a first semiconductor laser and a first photodiode arranged opposite each other, forming a first optical path. Tin particles released by the tin particle generation module fall through the first optical path. The second optical path detection mechanism is located below the first optical path detection mechanism. The second optical path detection mechanism includes a second semiconductor laser and a second photodiode arranged opposite each other, forming a second optical path. Tin particles released by the tin particle generation module fall through the first optical path and then through the second optical path. The microcontroller is connected to the first photodiode and the second photodiode respectively to receive the photoelectric signals generated by the first photodiode and the second photodiode respectively.

[0010] According to the present invention, a device for detecting the characteristics of moving tin particles is provided, wherein the microcontroller has a built-in timer, the timer counts according to a set clock frequency, and the microcontroller calibrates the time count value of the received photoelectric signal based on the timer.

[0011] According to the present invention, a motion tin particle feature detection device is provided, wherein the motion speed measurement module further includes a first signal enhancement module and a second signal enhancement module. The first signal enhancement module includes a first transimpedance amplifier circuit and a first voltage comparator circuit connected together. The first transimpedance amplifier circuit is connected to the first photodiode, and the first voltage comparator circuit is connected to the microcontroller. The second signal enhancement module includes a second transimpedance amplifier circuit and a second voltage comparator circuit connected together. The second transimpedance amplifier circuit is connected to the second photodiode, and the second voltage comparator circuit is connected to the microcontroller.

[0012] According to the present invention, a motion tin particle feature detection device is provided, wherein the time-lapse shooting module includes an industrial camera, the industrial camera is equipped with a telephoto lens, the telephoto lens is located on one side below the tin particle generation module and is positioned directly below the tin particle generation module; the industrial camera is connected to the first voltage comparison circuit, and the industrial camera is triggered to start and perform time-lapse shooting based on the falling edge signal output by the first voltage comparison circuit.

[0013] According to the present invention, a motion tin particle feature detection device is provided, wherein the time-lapse shooting module further includes an LED fill light, which is located on the opposite side of the tin particle generation module and opposite to the telephoto lens.

[0014] This utility model provides a device for detecting moving tin particles. The device adopts a modular design and mainly includes four functional modules: a tin particle generation module, a motion velocity measurement module, a time-lapse imaging module, and an image processing and analysis module. These modules are arranged sequentially according to the tin particle's motion path, forming a complete detection system. The tin particle generation module is located at the top of the device, enabling quantitative release control of the tin particles. This module is equipped with a collimation channel to ensure that the tin particles maintain a vertical falling trajectory under gravity, providing a stable motion reference for subsequent detection. The motion velocity measurement module is located below the generation module, calculating the instantaneous falling velocity of the tin particles in real time. Simultaneously, based on the velocity calculation results, it determines the optimal time-lapse parameters for synchronous imaging. The time-lapse imaging module is located below the velocity measurement module, receiving trigger signals from the velocity measurement module and capturing images at precisely calculated delay times to ensure the capture of optimal images of the tin particles passing through the detection area. The image processing and analysis module is connected to the time-lapse imaging module and is responsible for processing and analyzing the acquired images. This invention achieves high-precision measurement of characteristic parameters of moving tin microparticles through the coordinated work of various modules. Compared with traditional methods, this invention has the advantages of simple structure, low cost and strong environmental adaptability. It can complete accurate measurements under normal pressure conditions, providing reliable experimental means and technical support for the analysis of the motion behavior of tin droplets in extreme ultraviolet light source (EUV) research. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in 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 some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0016] Figure 1 This is an isometric structural diagram of the motion tin particle feature detection device provided by this utility model.

[0017] Figure 2 This is a schematic diagram of the main structure of the motion tin particle feature detection device provided by this utility model.

[0018] Figure 3 This is a schematic diagram of the tin microparticle generation module provided by this utility model.

[0019] Figure 4 This is a schematic diagram of the photoelectric detection structure of the motion speed measurement module provided by this utility model.

[0020] Figure 5 This is a schematic diagram of the signal output of the tin microparticle velocity measurement module provided by this utility model.

[0021] Figure 6 This is a schematic diagram of the working structure of the time-lapse shooting module provided by this utility model.

[0022] Figure 7 This is a flowchart illustrating the method for detecting the characteristics of moving tin particles provided by this utility model.

[0023] Figure 8 This is a functional flowchart of the motion speed measurement module provided by this utility model.

[0024] Figure 9 This is a functional flowchart of the time-lapse shooting module provided by this utility model.

[0025] Figure 10 This is a functional flowchart of the image processing and analysis module provided by this utility model.

[0026] Figure 11 These are images and results illustrating a detection example of the method for detecting the characteristics of moving tin particles provided by this utility model.

[0027] Reference numerals: 1. Tin microparticle funnel; 2. Funnel base; 3. First support frame; 4. Motor; 5. Output shaft; 6. Collimation channel tube; 7. Micro-orifice; 8. First semiconductor laser; 9. First photodiode; 10. Second semiconductor laser; 11. Second photodiode; 12. Microcontroller; 13. First signal enhancement module; 131. First transimpedance amplifier circuit; 132. First voltage comparator circuit; 14. Second signal enhancement module; 141. Second transimpedance amplifier circuit; 142. Second voltage comparator circuit; 15. Industrial camera; 16. Telephoto lens; 17. LED fill light; 18. Device base plate; 19. Device base; 20. Base fixing bolt; 21. Second support frame; 22. Motion speed measurement base; 23. Photoelectric detection slide rail; 24. Motor fixing bracket; 25. Photoelectric detection fixing stage; 26. Lamp holder fixing base; 27. Industrial camera bottom slide. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0029] The following is combined with Figures 1 to 11 This invention describes a device for detecting the characteristics of moving tin particles.

[0030] One embodiment of this utility model provides a device for detecting the characteristics of moving tin particles, combined with... Figure 1 and Figure 2 As shown, the system includes a tin particle generation module, a motion speed measurement module, a time-lapse imaging module, and an image processing and analysis module. The tin particle generation module controls the release and vertical descent of the tin particles. The motion speed measurement module, located below the tin particle generation module, detects the instantaneous velocity of the falling tin particles. The time-lapse imaging module, located below the motion speed measurement module and connected to it, is triggered by the motion speed measurement module and performs delayed snapshots to capture the falling motion pattern of the tin particles. The image processing and analysis module, connected to the time-lapse imaging module, receives the images captured by the time-lapse imaging module and analyzes the size and positional offset of the generated tin particles.

[0031] It is understood that this moving tin microparticle feature detection device in this embodiment achieves precise release control of tin microparticles through a tin microparticle generation module, ensuring that the tin microparticles fall stably and vertically under the action of gravity; the motion speed measurement module calculates the instantaneous motion speed of the tin microparticles in real time and triggers the time-lapse imaging module to work in a time delay mode. Based on the instantaneous motion speed, the delay time required for the tin microparticles to move from the trigger point to the time-lapse imaging module is calculated, and the delay trigger parameters of the time-lapse imaging module are set accordingly, realizing high-precision synchronous shooting control of the moving tin microparticles; the time-lapse imaging module achieves precise capture of the moving tin microparticles, obtaining clear high-contrast outlines of the tin microparticles, ensuring the accuracy of subsequent image processing and feature extraction; the image processing and analysis module is responsible for receiving the image data captured by the time-lapse imaging module, extracting key feature information such as the size of the tin microspheres and their offset from the predetermined position through image processing algorithms, and displaying the processing results in real time.

[0032] It is important to understand that the "synchronous imaging" involved in this embodiment refers to the time-delay imaging module capturing images simultaneously as the tin particles pass by. The time-delay imaging module needs to wait for a delay after triggering before capturing images. Based on this embodiment, the moving tin particle feature detection device can efficiently and accurately measure key characteristics such as the speed, size, and offset from a predetermined position of moving tin particles. This overcomes the reliance on high-cost equipment and complex experimental environments in the generation and monitoring of tin droplets in traditional extreme ultraviolet (EUV) light sources, achieving simplified and controllable experimental conditions. Through real-time detection and analysis of the characteristics of moving tin particles, it provides reliable experimental data and technical support for the study of the generation and motion behavior of tin droplets in extreme ultraviolet (EUV) light sources.

[0033] In some embodiments of the motion tin particle feature detection device of this utility model, combined with Figure 1 and Figure 3As shown, the tin microparticle generation module includes a tin microparticle funnel 1, a motor 4, and a collimation channel tube 6. The tin microparticle funnel 1 is inserted through a funnel base 2, which is mounted on a first support frame 3. The output shaft 5 of the motor 4 is inserted through the outlet of the tin microparticle funnel 1 to control the quantitative release of tin microparticles. The collimation channel tube 6 is vertically connected to the outlet of the tin microparticle funnel 1 to guide the tin microparticles to fall vertically. It can be understood that the tin microparticle generation module, composed of the tin microparticle funnel 1, the motor 4, and the collimation channel tube 6, achieves precise release control of the tin microparticles in the tin microparticle funnel 1 through the output shaft 5 of the motor 4, ensuring that the tin microparticles fall stably and vertically under gravity.

[0034] Specifically, in some examples, the output shaft 5 is provided with a micropore 7 at the position corresponding to the outlet of the tin particle funnel 1. Figure 3 The micro-orifice 7 shown is in the state before being inserted into the tin microparticle funnel 1. The diameter of the micro-orifice 7 is suitable for allowing one tin microparticle to enter and be temporarily stored. It can be understood that the motor 4 (DC motor) drives the micro-orifice 7, which is located on the output shaft 5, to rotate at a constant speed. The diameter of the output shaft 5 can be adjusted according to the actual size of the tin microparticles, designed so that the orifice diameter is slightly larger than the diameter of a single tin microparticle, allowing only one tin microparticle to enter and be temporarily stored. When the output shaft 5 rotates, one tin microparticle in the tin microparticle funnel 1 enters the micro-orifice 7. As the micro-orifice 7 rotates and aligns precisely with the outlet of the tin microparticle funnel 1, a tin microsphere is released into the collimation channel tube 6. The motor 4 can be set to rotate at a constant speed, and combined with the mechanical distribution characteristics of the micro-orifice 7, a quantitative release mechanism of "one particle per rotation" can be achieved. The tin microparticle funnel 1 is used to collect tin microspheres and guide them into the micropore 7. The collimation channel tube 6 set below can effectively prevent the tin microparticles from shifting laterally during the release process, ensuring that they fall vertically along a fixed path under the action of gravity. The tin microparticle generation module in this example can adjust the release frequency of tin microparticles by controlling the rotation speed of the motor 4, and has good adjustability, repeatability and stability.

[0035] In some embodiments of the motion tin particle feature detection device of this utility model, combined with Figure 2 and Figure 4As shown, the motion speed measurement module includes a first optical path detection mechanism, a second optical path detection mechanism, and a microcontroller 12. The first optical path detection mechanism includes a first semiconductor laser 8 and a first photodiode 9 arranged opposite each other, forming a first optical path between them. The first optical path is located below the tin particle generation module so that the tin particles released by the tin particle generation module fall through the first optical path. The second optical path detection mechanism is located below the first optical path detection mechanism and includes a second semiconductor laser 10 and a second photodiode 11 arranged opposite each other, forming a second optical path between them. The tin particles released by the tin particle generation module fall through the first optical path and then through the second optical path. The microcontroller 12 is connected to the first photodiode 9 and the second photodiode 11 respectively to receive the photoelectric signals generated by the first photodiode 9 and the second photodiode 11 respectively.

[0036] Understandably, the motion speed measurement module consists of a photoelectric detection mechanism composed of two sets of semiconductor lasers and photodiodes, as well as a microcontroller system. Its core function is to measure the instantaneous velocity of tin particles during free fall in real time, and calculate the delay trigger time of the time-lapse imaging module accordingly, achieving high-precision imaging timing synchronization. See again. Figure 1 As shown, two photoelectric detection mechanisms are arranged vertically below the tin particle generation module. The first optical path detection mechanism consists of a first semiconductor laser 8 and a first photodiode 9, while the second optical path detection mechanism consists of a second semiconductor laser 10 and a second photodiode 11. In some specific examples, the wavelengths of the first semiconductor laser 8 and the second semiconductor laser 10 are 650nm, and their power is 60mW. The receiving target surface size of the first photodiode 9 and the second photodiode 11 is 1mm*1mm. After collimation and focusing, the output beams of the first semiconductor laser 8 and the second semiconductor laser 10 form a minimum spot size of approximately 100μm at a focal length of 10cm, stably covering the receiving target surface of the corresponding photodiode. When the tin particles fall and pass through the laser optical path, they block the laser, causing the output current of the corresponding photodiode to decrease instantaneously, forming a weak falling edge signal, which is input to the microcontroller 12. The two general-purpose input interfaces of the microcontroller 12 are connected to the two photodiodes respectively and configured in external interrupt mode to capture the falling edge pulse signal generated by the laser blocking.

[0037] Furthermore, in order to enhance the amplitude of the signal and facilitate subsequent processing, in some embodiments, the motion speed measurement module further includes a first signal enhancement module 13 and a second signal enhancement module 14. The first signal enhancement module 13 includes a first transimpedance amplifier circuit 131 and a first voltage comparator circuit 132 connected together. The first transimpedance amplifier circuit 131 is connected to a first photodiode 9, and the first voltage comparator circuit 132 is connected to a microcontroller 12. The second signal enhancement module 14 includes a second transimpedance amplifier circuit 141 and a second voltage comparator circuit 142 connected together. The second transimpedance amplifier circuit 141 is connected to a second photodiode 11, and the second voltage comparator circuit 142 is connected to a microcontroller 12.

[0038] Understandably, see Figure 5 As shown, the weak current signal output by the first photodiode 9 in the first optical path detection mechanism is first converted into a voltage signal with an amplitude of approximately 3V by the first transimpedance amplifier circuit 131, and then input to the first voltage comparison circuit 132. The reference voltage of the first voltage comparison circuit 132 is set to 2.5V. When the input voltage of the first voltage comparison circuit 132 is lower than this threshold, the first voltage comparison circuit 132 outputs a low-level pulse to indicate the moment when the tin particle passes through the first optical path. Similarly, in the second optical path detection mechanism, the weak current signal output by the second photodiode 11 is first converted into a voltage signal with an amplitude of approximately 3V by the second transimpedance amplifier circuit 141, and then input to the second voltage comparison circuit 142. The reference voltage of the second voltage comparison circuit 142 is also set to 2.5V. When the tin particle falls and moves through the second optical path, the second voltage comparison circuit 142 also outputs a low-level pulse to indicate the moment when the tin particle passes through the second optical path.

[0039] The two general-purpose input interfaces of the microcontroller 12 are respectively connected to the output terminals of two voltage comparison circuits and configured as external interrupt mode to capture the falling edge pulse signal generated by laser blocking. In order to achieve high-precision time measurement, in some specific examples, the microcontroller 12 has a built-in timer. The timer counts according to the set clock frequency, and the microcontroller 12 calibrates the time count value of the received photoelectric signal based on the timer.

[0040] It is important to understand that when the tin particles sequentially pass through the two laser beams, the photodiodes detect the obstruction event, generating two falling edge signals, which are input to the microcontroller 12. The microcontroller 12 accurately records the time interval between the two signals and, combined with the known spatial distance between the laser beams, calculates the instantaneous velocity of the tin particles in real time. Furthermore, based on this velocity information, the microcontroller 12 further calculates the delay time required for the tin particles to move from the trigger point to the time-delay imaging module, and sets the camera's delay trigger parameters accordingly, achieving high-precision synchronous imaging control of the moving tin particles.

[0041] Specifically, the timer runs continuously after initialization and counts according to the set clock frequency. When the first pulse signal arrives and triggers a falling edge interrupt, the microcontroller immediately reads the current timer count value N1. When the second pulse signal arrives, it triggers another interrupt and reads the current count value N2. The count difference between the two pulse signals is: N = N2 - N1. Combining this with the timer's clock frequency, this time difference can be converted into the time interval between the tin particles passing through the two laser beams, which can be calculated using the following formula: Formula 1 In the formula, N is the time interval between two pulse signals; N is the pulse count difference recorded by the microcontroller's timer. This is the timer clock frequency.

[0042] This time interval This can be used to further calculate the velocity of the tin particle passing between two laser beams and the camera delay time. The vertical distance Δs between the laser beam paths generated by the two semiconductor lasers is a known and fixed constant. The tin particle is in free fall and is subject to gravitational acceleration. Its effect, its speed increases linearly with time; tin particles in the time interval Within, moving from the position of the first laser beam path to the position of the second laser beam path satisfies the following formula two: Formula 2 From this, the instantaneous velocity when passing through the path of the first laser beam can be deduced. , The following formula three must be satisfied: Formula 3 Then based on the instantaneous velocity Calculate the delay trigger time required for the tin microparticle to travel the vertical distance L from the position of the first laser beam to the center of the field of view of the industrial camera in the time-delay imaging module. The displacement relationship satisfies the following formula four: Formula 4 By solving Formula 4, the camera's trigger delay parameter can be obtained. This ensures that the industrial camera initiates exposure when the tin particles reach the center of the field of view.

[0043] In the above formula, This represents the time interval between two pulse signals measured by the microcontroller. This represents the perpendicular distance between the two laser beam paths. This represents the instantaneous velocity of the tin particles as they pass through the path of the first laser beam. This represents the acceleration due to gravity, approximately 9.8 m / s².2 L represents the vertical distance from the position of the tin particle in the first laser beam path to the center of the industrial camera's field of view. This indicates the delay time triggered by an external source from an industrial camera.

[0044] In some embodiments of the motion tin particle feature detection device of this utility model, the time-lapse shooting module includes an industrial camera 15, on which a telephoto lens 16 is mounted. The telephoto lens 16 is located on one side below the tin particle generation module and is positioned directly below the tin particle generation module. The industrial camera 15 is connected to a first voltage comparison circuit 132. The industrial camera 15 is triggered and starts to perform time-lapse shooting based on the falling edge signal output by the first voltage comparison circuit 132.

[0045] Understandably, see Figure 6 As shown, the working structure of the time-lapse imaging module consists of an industrial camera 15 and a first optical path detection mechanism composed of a first semiconductor laser 8 and a first photodiode 9 in the motion speed measurement module. When a tin particle first passes through the first optical path, the first photodiode 9 receives an obstruction signal and generates a falling edge. After processing by the first transimpedance amplifier circuit 131 and the first voltage comparator circuit 132, it is sent to the industrial camera 15 as an external trigger signal. Before this, the delay time required for the tin particle to move from the trigger point to the center of the field of view of the industrial camera 15 is measured by the motion speed measurement module. The corresponding time-lapse imaging parameters of the industrial camera 15 are manually set. The industrial camera 15 is triggered based on the falling edge signal processed by the first voltage comparator circuit 132, and then takes a picture after the set delay time to achieve accurate capture of the moving tin particle.

[0046] To improve image quality, in some examples, the time-lapse module also includes an LED fill light 17, located below the tin particle generation module on the opposite side from the telephoto lens 16. In this example, the LED fill light 17 serves as a backlight, working in conjunction with the light source controller to provide stable and high-brightness backlighting during exposure by the industrial camera 15. Combined with shadow imaging technology, this allows for clear, high-contrast outlines of the tin particles in the image, ensuring the accuracy of subsequent image processing and feature extraction.

[0047] During device operation, the first semiconductor laser 8 emits a laser beam, which, after collimation and focusing, forms a minimum spot size of approximately 100μm at 10cm, stably covering the receiving target surface of the first photodiode 9. When the tin microsphere falls through the laser beam, it is blocked, causing a sudden change in the light intensity received by the first photodiode 9, resulting in the output of a weak current signal. This signal first enters the first transimpedance amplifier circuit 131, which converts the weak current into a voltage and amplifies it to 3V for subsequent identification and processing. The amplified voltage signal is then sent to the first voltage comparison circuit 132 and compared with a set threshold voltage (2.5V). Once the signal voltage drops above the threshold (over 500mV), the circuit outputs a clear TTL low-level pulse signal, indicating that the tin microsphere has crossed the optical path, completing a precise external trigger event. This trigger signal is then transmitted to the industrial camera 15. Combined with the delay time previously calculated by the speed measurement module, the industrial camera 15 is controlled to start exposure at the optimal moment when the tin microsphere is exactly at the center of the field of view, thereby achieving high-precision synchronous imaging and ensuring the capture of a clear image. In high-speed imaging, extremely short exposure times are typically required to ensure image sharpness, making the system's imaging illuminance E particularly critical. According to the illuminance formula: Where E is the imaging illuminance, L is the subject brightness, τ is the system transmittance, D is the aperture diameter, and f is the focal length.

[0048] Visible image illuminance E and subject brightness L, lens transmittance and the square of the aperture diameter Proportional to the square of the lens focal length Inversely proportional to brightness, it can significantly improve imaging illumination, thereby effectively ensuring image clarity under high-speed exposure conditions. Therefore, LED fill light 17 is used to enhance brightness and ensure image clarity under high-speed exposure conditions.

[0049] The image processing and analysis module of this utility model receives images captured by the time-lapse imaging module and analyzes the size and positional offset of the generated tin microparticles through key steps such as image acquisition, preprocessing, edge detection, contour extraction, feature calculation, and result display.

[0050] Based on the structure and principle of the above-mentioned embodiments of the tin particle generation module, motion speed measurement module, time-lapse imaging module, and image processing and analysis module, in some embodiments of the motion tin particle feature detection device of this utility model, further combined with Figure 1 and Figure 2As shown, the motion tin particle feature detection device includes a device base plate 18, a device base 19 is set below the device base plate 18, the device base 19 is inserted into the device base plate 18 by base fixing bolts 20, a second support frame 21 is set on the device base plate 18, a motion speed measuring base 22 is set on the top of the second support frame 21, a photoelectric detection slide rail 23, a first support frame 3 and a motor fixing bracket 24 are fixed on the motion speed measuring base 22, a funnel base 2 is set on the top of the first support frame 3, a tin particle funnel 1 is set on the funnel base 2, the motor fixing bracket 24 is used to install the motor 4, a photoelectric detection fixing stage 25 is slidably set on the photoelectric detection slide rail 23, a first semiconductor laser 8, a first photodiode 9, a second semiconductor laser 10 and a second photodiode 11 are fixed on the photoelectric detection fixing stage 25, the fine adjustment function of the photoelectric detection slide rail 23 can correct the optical axis alignment deviation of the laser and the photodiode, and avoid signal distortion caused by installation misalignment. A lamp holder mounting base 26 is provided on one side of the second support frame 21. The lamp holder mounting base 26 is used to fix and install the LED fill light 17. A bottom slide 27 for an industrial camera 15 is provided on the device base plate 18 at a position opposite to the lamp holder mounting base 26. The bottom slide 27 allows the industrial camera 15 to move in the horizontal plane, ensuring that the falling trajectory of the tin particles strictly passes through the center of the camera's field of view. Adjusting the position of the industrial camera 15 by using the bottom slide 27 can compensate for timing errors when falling from different heights, ensuring that the tin particles are exposed precisely when they reach the center of the field of view. At the same time, the bottom slide 27 can adjust the distance between the industrial camera 15 and the falling path to maintain image clarity. The device base plate 18 is also provided with a first signal enhancement module 13, a second signal enhancement module 14, and a microcontroller 12.

[0051] Based on the structure of the moving tin particle feature detection device in the above embodiments, this utility model can implement a moving tin particle feature detection method, applicable to the moving tin particle feature detection device in any of the above embodiments for moving tin particle feature detection. The moving tin particle feature detection method includes the following: releasing tin particles based on the tin particle generation module, causing the tin particles to undergo free fall motion under the action of gravity. Detecting the instantaneous falling velocity of the tin particles as they pass by based on the motion velocity measurement module, and calculating the delay time required for the tin particles to move from the trigger point to the time-lapse imaging module, the time-lapse imaging module performs snapshot capture based on the delay time. Capturing the motion pattern of the tin particles as they pass by based on the time-lapse imaging module, obtaining the shadow image of the tin particles. Based on the shadow image of the tin particles captured by the time-lapse imaging module, performing image processing and analysis through the image processing and analysis module to obtain the size of the tin particles and their offset relative to a predetermined position.

[0052] The process involves several steps: First, a motion speed measurement module detects the instantaneous falling speed of tin particles as they pass by. Then, it calculates the time delay required for the tin particles to travel from the trigger point to the time-lapse imaging module. The time-lapse imaging module performs snapshot capture based on this delay. Specifically, when the tin particles fall through the first optical path detection mechanism, they block the first optical path. The first photodiode 9 generates a first photoelectric signal, which is transmitted to the microcontroller 12. The first time count value corresponding to the first photoelectric signal generated by the first photodiode 9 is recorded. When the tin particles fall through the second optical path detection mechanism, they block the second optical path. The second photodiode 11 generates a second photoelectric signal, which is transmitted to the microcontroller 12. The second time count value corresponding to the second photoelectric signal generated by the second photodiode 11 is recorded. The instantaneous falling speed of the tin particles when they pass through the first optical path detection mechanism is calculated based on the first and second time count values. Finally, the time delay required for the tin particles to reach the time-lapse imaging module is calculated based on the instantaneous falling speed of the tin particles when they pass through the first optical path detection mechanism. The time-delay shooting module is set to the time-delay time calculated by the microcontroller. The time-delay shooting module is started based on the first photoelectric signal trigger and performs shooting after the time-delay period.

[0053] Figure 7 This is a flowchart illustrating the workflow of the moving tin particle feature detection device system of this invention, showing the overall detection process from signal acquisition to image analysis and result output. The entire process is divided into the following stages: S1. Initialize the device: Connect and configure the tin particle generation module and the motion velocity measurement module. Adjust the release frequency of the tin particle generation module to ensure that the tin particles fall freely along the collimation channel in a stable state and enter the trigger area.

[0054] S2. Tin microparticle release and falling guidance: The tin microparticles are released at a set frequency by the motor 4 and the funnel structure of the tin microparticle funnel 1. The tin microparticles fall vertically through the collimation channel tube 6, effectively avoiding lateral deviation, and enter the motion speed measurement and external triggering area in sequence, laying the foundation for subsequent synchronous shooting and image processing.

[0055] S3. Motion Speed ​​Measurement: Tin particles pass sequentially through two laser beams, and a falling edge signal is generated by a detection mechanism composed of a semiconductor laser and a photodiode. The microcontroller 12 collects the time interval between the signals and calculates the instantaneous velocity of the tin particles and the motion time from the trigger point to the center of the field of view of the industrial camera 15, which is used as the accurate time for the external trigger delay of the camera.

[0056] S4. Configure camera parameters: Connect the industrial camera 15 and set the operating parameters of the industrial camera 15 (exposure time, gain, trigger mode, trigger delay, etc.) through the host computer interface, and prepare to wait for the external trigger signal.

[0057] S5. External trigger signal generation and synchronous shooting: When the tin particles pass through the first optical path detection mechanism, the first photodiode 9 detects the sudden change in light intensity and generates a falling edge signal. After amplification and shaping, it serves as the external trigger signal for the industrial camera 15. The industrial camera 15 performs delayed snapshot according to the configuration parameters to achieve high-precision synchronous shooting. With the help of the LED fill light 17 backlight, a clear shadow image is obtained.

[0058] S6. Image Processing and Feature Extraction: After the captured image is transmitted to the host computer, image preprocessing (denoising, edge detection, contour extraction) is performed. The key feature parameters such as the diameter, area, and offset of the tin particles are accurately extracted through image processing algorithms.

[0059] S7. Result Display and Analysis: The processed images and parameters are displayed in real time on the host computer interface, including a multi-view area of ​​the original image, preprocessed image, edge detection image and contour detection image. At the same time, key feature information such as the size of tin particles and the offset relative to the predetermined position are displayed simultaneously, which makes it convenient for users to analyze the motion state and geometric characteristics of tin particles in real time and provide intuitive and effective data support for experimental research.

[0060] The following describes the specific process of the motion tin particle feature detection method of this utility model based on the motion speed measurement module, time-lapse photography module, and image processing and analysis module, respectively.

[0061] See Figure 8 As shown, the motion speed measurement module of this utility model calculates the motion speed of tin particles and the camera delay trigger time by detecting signals as follows: S11. Initialize the system timer and external interrupt module: Initialize the timer and external interrupt module in the microcontroller 12, and set a fixed clock frequency. It is configured with two general-purpose I / O pins as external interrupt inputs to receive the output signals of the first and second photoelectric detection mechanisms, respectively, providing a basis for speed measurement.

[0062] S12. Monitor whether the first falling edge signal has arrived: The system enters a waiting state and continuously monitors whether the first falling edge signal generated by the first optical path being blocked by tin particles is detected. If not detected, continue to wait; once the signal is detected, start executing step S13.

[0063] S13. Record the time T1 corresponding to the first falling edge (count value N1): After detecting the first falling edge, immediately read the current timer count value N1 and use it as the first reference time point T1.

[0064] S14. Monitor for the arrival of the second falling edge signal: The system continues to wait for the second falling edge signal, which corresponds to the blocking event generated when tin particles pass through the second optical path. If no signal is detected, the system remains in a waiting state; if a signal is detected, step S15 is executed.

[0065] S15. Record the time T2 corresponding to the second falling edge (count value N2): After detecting the second falling edge, record the current timer count value T2 as the second reference time point.

[0066] S16. Calculate the time interval between two falling edges. The time interval between two events is calculated based on the timer count difference and the clock frequency.

[0067] S17, Judgment Is it within a reasonable time window? If If the signal exceeds a reasonable range (e.g., too small or too large, possibly caused by false triggering or abnormal interference), return to step S12 to re-detect the signal; if Reasonable. Proceed to the next calculation.

[0068] S18. Calculate the instantaneous velocity of the tin particle as it passes through the first optical path. .

[0069] S19. Calculate the camera trigger delay time. Based on the velocity calculated in step S18, estimate the time required for the tin microparticle to travel the vertical distance L from the location of the first optical path to the center of the industrial camera's field of view. .

[0070] S10, Output speed and delay information: The calculated instantaneous speed and camera delay time are displayed on the OLED screen of the microcontroller 12 to complete the detection process.

[0071] See Figure 9 As shown, the functional flow of the time-lapse shooting module of this utility model specifically includes the following steps: S21. Process Start: Start the externally triggered time-lapse shooting module and prepare to enter the parameter configuration and shooting response process.

[0072] S22. Configure camera parameters: Configure relevant parameters of the industrial camera, including setting key parameters such as exposure time, gain value, trigger mode (usually external trigger mode), trigger source (falling edge level of the first voltage comparison circuit 132), and trigger delay (delay time calculated by the microcontroller 12), to ensure that the camera can perform image acquisition in the set manner after receiving the trigger signal.

[0073] S23. Determine if an external trigger signal has been received: The system continuously monitors for external trigger signals from the photoelectric detection module. If no signal has been received, it continues to wait; once an external trigger signal is received, proceed to the next step.

[0074] S24. Perform image acquisition operation: The camera starts the shutter exposure and acquires the current image according to the external trigger signal and delay setting, so as to achieve precise synchronous shooting with the high-speed moving tin microsphere.

[0075] S25. Determine if the image save directory exists: The system checks if the image save path has been created. If not, the save directory is automatically generated; if the save path exists, this step is skipped.

[0076] S26. Save Images: Save the acquired image files to the specified directory according to the timestamp or number naming method for easy subsequent image processing and analysis.

[0077] S27. Determine if an interrupt signal has been received: The system determines whether a stop command or other interrupt signal has been received. If not, the process returns to step S23, continues to wait for and respond to the next external trigger signal, and realizes cyclic shooting; if an interrupt signal is received, the process ends.

[0078] See Figure 10 As shown, the image processing and analysis module executes the following functional flow during operation: S31. Process Start: Start the image processing and analysis module to prepare for receiving and processing images.

[0079] S32. Receive images from industrial cameras: Continuously acquire raw images output by industrial cameras through the communication interface to ensure the integrity and continuous transmission of image data.

[0080] S33. Image Preprocessing: To improve the accuracy of subsequent analysis, grayscale conversion is used to convert the images captured by the industrial camera into single-channel grayscale images, and Gaussian filtering is applied for noise suppression. The kernel size and standard deviation of the Gaussian filter are dynamically adjusted according to the specific image noise level to smooth the image while preserving key details. The main calculations include: Grayscale conversion, the calculation formula is: Where I(x,y) is the pixel value at coordinates (x,y) in the grayscale image, and R(x,y), G(x,y), and B(x,y) represent the red, green, and blue channel pixel values ​​at the corresponding coordinates in the original color image, respectively. Grayscale conversion combines the red, green, and blue channels of the color image into a single-channel grayscale image using a weighted average, reducing data redundancy and facilitating subsequent processing.

[0081] Gaussian filtering for noise reduction: A two-dimensional Gaussian function is used to smooth the grayscale image. The kernel size and standard deviation are adjusted according to the experimental environment to effectively suppress image noise and improve the accuracy of edge detection. The filtering calculation formula is as follows: in, (x, y) represents the pixel value at coordinates (x, y) in the filtered image. This represents the pixel values ​​within the neighborhood of a grayscale image, where K is the convolution kernel radius, which determines the size of the filtering region. The two-dimensional Gaussian kernel weights are defined as follows: in, The standard deviation of the Gaussian function is used to control the filtering strength (which can be set according to the noise level of the experimental image).

[0082] S34. Edge Detection: The Canny edge detection algorithm, which adjusts the threshold based on the image features of tin microspheres, is used to detect the edges of tin microspheres in the image. By calculating the pixel gradient magnitude and direction, and combining non-maximum suppression and dual threshold filtering, strong and weak edges are accurately distinguished, and a clear binary edge map is finally obtained. Where I represents the grayscale value function of the image, which is the input grayscale image; and The image grayscale values ​​are respectively in and Gradient in the direction.

[0083] Gradient magnitude and direction: Calculate the gradient magnitude and edge direction angles. in, This represents the gradient magnitude, reflecting the edge intensity. The gradient direction angle represents the edge direction angle.

[0084] Non-maximum suppression and dual-threshold detection: Pixel-level filtering of the gradient magnitude map retains only local maxima along the gradient direction, setting other pixels to 0, thereby refining edges and suppressing edge diffusion. A high threshold TH and a low threshold TL are set to classify pixels as follows: strong edges (greater than TH) are identified as true edges; weak edges (between TL and TH) may be edges but need to be attached to strong edges; non-edges (less than TL) are suppressed as background. Edge connection: Pixels connected to strong edges within weak edges are retained, while the rest are discarded, thus removing isolated noise and false edges, resulting in a clear binary edge image.

[0085] S35. Contour Detection: Based on the edge image, the OpenCV library's contour detection function cv2.findContours is called to detect closed contours. The steps are as follows: Identify all closed edges to form a contour set {Ci}, where each contour consists of several points. Contours are filtered by area, removing those that are too small or too large, retaining only valid contours that conform to the size range of the tin microspheres.

[0086] S36. Feature Extraction: For each selected contour, calculate its covered pixel area and equivalent circular diameter. Obtain the centroid coordinates using the contour moment method, and calculate the horizontal and vertical offset distances of the centroid using the image center as a reference. To achieve the measurement of actual physical quantities, all pixel units are converted to micrometers and micrometer squared units using pre-calibrated camera pixel dimensions. The calculations are as follows: For each preserved contour Ci, calculate the key physical feature parameters: Calculate the pixel area covered by the outline: in This represents the pixel area of ​​the i-th contour, expressed in pixels squared. 2 ).

[0087] Calculate the equivalent circle diameter based on the contour area: , in The equivalent circle diameter of the i-th contour is expressed in pixels.

[0088] Calculate the centroid coordinates using profile moments: The centroid coordinates are defined as follows: ,in, The zeroth moment represents the area of ​​the profile; , , , and , respectively, represent the first-order moments, and , respectively, the weighted sums of image pixels in the x and y directions; Let x be the horizontal and vertical coordinates of the centroid of the i-th contour in the image coordinate system.

[0089] Offset calculation with reference point: Let the image center point be... Calculate the relative center offset of the tin microsphere's centroid: , .in, , These are the horizontal and vertical offsets, respectively (unit: pixels). , These are the x and y coordinates of the centroid of the tin microsphere (unit: pixels).

[0090] Physical unit conversion: Convert pixel units to actual physical size: in, This indicates the physical size (μm / pixel) of a single pixel in the camera, with superscripts (μm) and (μm). 2 () indicates the converted physical size unit.

[0091] S37. Result Visualization Generation: High-contrast colored lines are used to mark the outer contour of the tin microspheres on the contour detection image. The centroid position of each tin microsphere is marked in the image, and the image center is simultaneously marked as a reference point to assist in subsequent offset determination. Simultaneously, images from different stages of the image processing are output, including: original image, preprocessed image, edge detection image, and contour extraction image. Key parameter information is overlaid to display the key physical parameters obtained in real-time detection, including: area (unit: μm). 2 ), equivalent circle diameter (unit: μm) center coordinates and horizontal / vertical offset from the image center point (unit: μm).

[0092] S38. Determine if there is an interrupt signal: Detect if there is a program termination or stop command. If there is no interrupt signal, return to step S32 to continue looping the processing of new images; if there is an interrupt signal, end the process.

[0093] It is important to understand that the key parameters involved in the image processing of this invention, including the standard deviation of Gaussian filtering, the high and low thresholds for edge detection, the area range for contour screening, and the physical size corresponding to image pixels, can all be flexibly configured and adjusted according to the imaging performance of the selected industrial camera, the characteristics of the target object, and the requirements of the specific application scenario. This adjustable parameter design effectively improves the system's adaptability under different environmental conditions and detection tasks, ensuring the stability and accuracy of the image processing results.

[0094] According to the steps of the moving tin microparticle feature detection method of this utility model, in order to verify the accuracy and applicability of the moving tin microparticle feature detection device and detection method of this utility model for detecting moving microparticles, in some specific embodiments, tin microspheres with a nominal diameter of 760μm are selected as test objects, and their dimensional error range specified by the manufacturer is ±5 to 10μm. The micro-hole 7 on the DC motor output shaft 5, located directly below the outlet of the tin microparticle funnel 1, has a diameter of 900μm. A Daheng Imaging Mercury II series industrial camera, model MER2-503-36U3M, is used. This camera is a black and white area array camera with a resolution of 2448×2048 and a pixel size of 3.45μm. Through a photoelectric triggering system combined with image processing algorithms, images of moving tin microparticles are accurately captured, and the characteristic parameters of the tin microspheres during movement are calculated and displayed in real time. The detection results are as follows: Detection area: 448581μm²; Equivalent diameter: 755.75 μm; Centroid coordinates: (4360.80μm, 4140.00μm); Offset relative to the image center point: horizontal offset Δx = 165.60μm, vertical offset Δy = 607.20μm.

[0095] To enhance the intuitiveness of the analysis results, this invention supports the graphical overlay display of detection information in images, and provides images at each stage of the entire image processing process, including the original image, preprocessed image, edge image, and contour image, facilitating comparative analysis. The detection results of the above specific embodiments can be found in [reference needed]. Figure 11 As shown, the final image not only fully preserves the original image information but also includes the following elements: the boundary contour of the tin microsphere (depicted by a green curve); the centroid of the detected object (depicted by blue), the image center point (described by red); and text annotations for result parameters such as area, equivalent diameter, and offset. The above detection examples and results demonstrate that the equivalent diameter of the tested tin microsphere is consistent with its nominal size, and the measurement error is controlled within the allowable range. This indicates that the device of this invention possesses high resolution, high repeatability, and excellent stability, enabling precise detection of high-speed moving microparticles (such as tin microspheres) in terms of size, position, and offset from a predetermined position.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A device for detecting the characteristics of moving tin particles, characterized in that, include: Tin microparticle generation module, used to control the release and vertical descent of tin microparticles; A motion speed measurement module, located below the tin particle generation module, is used to detect the instantaneous velocity of the falling tin particles; A time-lapse imaging module is located below the motion speed measurement module. The time-lapse imaging module is connected to the motion speed measurement module. The time-lapse imaging module is triggered and activated based on the motion speed measurement module to perform time-lapse capture, which is used to capture the falling motion pattern of tin particles. An image processing and analysis module is connected to the time-lapse imaging module. The image processing and analysis module receives the image captured by the time-lapse imaging module and analyzes the size and position offset of the generated tin particles.

2. The motion tin particle feature detection device according to claim 1, characterized in that, The tin particle generation module includes: Tin microparticle funnel (1), the tin microparticle funnel (1) is inserted through funnel base (2), the funnel base (2) is mounted on first support frame (3); The motor (4) has its output shaft (5) inserted through the outlet of the tin microparticle funnel (1) to control the quantitative release of tin microparticles. The collimation channel tube (6) is vertically connected to the outlet of the tin particle funnel (1) and is used to guide the tin particles to fall vertically.

3. The motion tin particle feature detection device according to claim 2, characterized in that, The output shaft (5) is provided with a microhole (7) at the position corresponding to the outlet of the tin particle funnel (1), and the diameter of the microhole (7) is suitable for allowing a tin particle to enter and be temporarily stored.

4. The motion tin particle feature detection device according to claim 1, characterized in that, The motion speed measurement module includes: The first optical path detection mechanism includes a first semiconductor laser (8) and a first photodiode (9) arranged opposite to each other, and a first optical path is formed between the first semiconductor laser (8) and the first photodiode (9). The tin particles released by the tin particle generation module fall through the first optical path. The second optical path detection mechanism is located below the first optical path detection mechanism. The second optical path detection mechanism includes a second semiconductor laser (10) and a second photodiode (11) arranged opposite to each other. A second optical path is formed between the second semiconductor laser (10) and the second photodiode (11). The tin particles released by the tin particle generation module fall through the first optical path and then through the second optical path. The microcontroller (12) is connected to the first photodiode (9) and the second photodiode (11) respectively, so as to receive the photoelectric signals generated by the first photodiode (9) and the second photodiode (11) respectively.

5. The motion tin particle feature detection device according to claim 4, characterized in that, The microcontroller (12) has a built-in timer, which counts according to a set clock frequency. The microcontroller (12) calibrates the time count value of the received photoelectric signal based on the timer.

6. The motion tin particle feature detection device according to claim 4 or 5, characterized in that, The motion speed measurement module also includes: The first signal enhancement module (13) includes a first transimpedance amplifier circuit (131) and a first voltage comparator circuit (132) connected together. The first transimpedance amplifier circuit (131) is connected to the first photodiode (9), and the first voltage comparator circuit (132) is connected to the microcontroller (12). The second signal enhancement module (14) includes a second transimpedance amplifier circuit (141) and a second voltage comparator circuit (142) connected together. The second transimpedance amplifier circuit (141) is connected to the second photodiode (11), and the second voltage comparator circuit (142) is connected to the microcontroller (12).

7. The motion tin particle feature detection device according to claim 6, characterized in that, The time-lapse shooting module includes an industrial camera (15), which is equipped with a telephoto lens (16). The telephoto lens (16) is located on one side below the tin microparticle generation module and is positioned directly below the tin microparticle generation module. The industrial camera (15) is connected to the first voltage comparison circuit (132). The industrial camera (15) is triggered and starts to perform time-lapse shooting based on the falling edge signal output by the first voltage comparison circuit (132).

8. The motion tin particle feature detection device according to claim 7, characterized in that, The time-lapse shooting module also includes an LED fill light (17), which is located on the opposite side of the tin microparticle generation module and opposite the telephoto lens (16).

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