Liquid drop generator

Abstract

The invention discloses a liquid drop generator. The liquid drop generator comprises a liquid storage barrel used for storing a working substance; the heating device is connected to the outer surface of the liquid storage barrel in a sleeving mode and used for heating the working substance in the liquid storage barrel so that the working substance can be molten into liquid; the needle connector is connected with the bottom of the liquid storage barrel and used for enabling liquid in the liquid storage barrel to flow out; the ultrasonic vibration device is used for applying disturbance to the liquid in the liquid storage barrel, so that the liquid in the liquid storage barrel forms a liquid drop sequence at the needle connector; the first end of the cooling cylinder is connected with the ultrasonic vibration device through a flange structure, the second end of the cooling cylinder is connected with the liquid storage barrel through a flange structure, and the cooling cylinder is used for reducing the temperature of the ultrasonic vibration device. Performance degradation and depolarization failure of the ultrasonic vibration device caused by high temperature are avoided, the reliability of the liquid drop generator is improved, and the service life of the liquid drop generator is prolonged. Meanwhile, independent disassembly and replacement of all the modules are achieved, and maintenance can be completed under the condition that other modules are not affected.

Description

Technical Field

[0001] This invention relates to the field of extreme ultraviolet light source technology, and more particularly to a droplet generator. Background Technology

[0002] In the field of extreme ultraviolet (EUV) lithography, the high-temperature plasma required to generate stable EUV light relies on a droplet generator capable of providing precise and stable metal droplets. The core function of this droplet generator is to apply high-frequency vibrational perturbation to the high-pressure ejected high-temperature molten metal stream, thereby breaking it into droplets of uniform size and repeating frequency. Currently, the mainstream technology for achieving this perturbation relies on piezoelectric ceramic actuators. However, because the working medium is molten metal (such as tin and its alloys), the droplet generator as a whole needs to be maintained in a high-temperature environment of several hundred degrees Celsius. The working mechanism of piezoelectric ceramic actuators is based on the stable orientation of their internal ferroelectric domains, and their piezoelectric properties are extremely sensitive to temperature. When the ambient temperature approaches the Curie point of the material, the ferroelectric domain structure gradually disintegrates due to thermal perturbation, causing the material to transition from a ferroelectric phase to a paraelectric phase. This leads to a significant deterioration of key performance parameters such as the piezoelectric constant and electromechanical coupling coefficient, and even irreversible depolarization failure, severely restricting the long-term operational stability and service life of the droplet generator.

[0003] To mitigate the challenges posed by high-temperature operating conditions, existing technologies have introduced solutions that couple a vibrating rod to a piezoelectric ceramic actuator, aiming to physically isolate the actuator from the high-temperature region. However, such designs generally suffer from a high degree of overlap between the vibration transmission path and the heat conduction path. While attempting to efficiently transfer mechanical vibration to the liquid flow, high-temperature heat is also conducted to the piezoelectric ceramic actuator along the same path, resulting in the actual operating temperature of the actuator remaining high and the performance degradation problem not being fundamentally solved. Furthermore, to achieve limited heat insulation, the related structures are often designed to be exceptionally complex and compact. This not only increases the difficulty and cost of manufacturing and maintenance but also limits the modularity and scalability of the system, making it difficult for users to adjust or optimize the droplet generator function according to actual needs.

[0004] Therefore, the existing technology still lacks a droplet generator structure that can achieve a balance between efficiently transmitting vibrational energy and effectively isolating heat transfer, which has become a key technical bottleneck restricting the improvement of the reliability of high-temperature metal droplet generators for extreme ultraviolet lithography. Summary of the Invention

[0005] This invention provides a droplet generator that effectively avoids the performance degradation and depolarization failure of ultrasonic vibration devices caused by high temperatures, and significantly improves the reliability and service life of the droplet generator.

[0006] This invention provides a droplet generator, comprising:

[0007] Storage tank, used to store working substances;

[0008] A heating device is fitted onto the outer surface of the liquid storage tank and is used to heat the working substance in the liquid storage tank so that the working substance melts into a liquid.

[0009] The needle connector is connected to the bottom of the liquid storage tank to allow the liquid in the storage tank to flow out.

[0010] An ultrasonic vibration device is used to agitate the liquid in the storage tank, causing the liquid in the storage tank to form a sequence of droplets at the needle connection port;

[0011] A cooling cylinder, the first end of which is connected to the ultrasonic vibration device via a flange structure, and the second end of which is connected to the liquid storage tank via a flange structure, are used to reduce the temperature of the ultrasonic vibration device.

[0012] Optionally, the cooling cylinder includes an outer cylindrical wall and an inner cylindrical wall;

[0013] A sandwich structure is formed between the outer cylindrical wall and the inner cylindrical wall, and the sandwich structure is filled with cooling water.

[0014] The inner cylindrical wall has a hollow structure inside, and the hollow structure is connected to the liquid storage tank.

[0015] Optionally, it also includes a cooling water inlet pipe and a cooling water outlet pipe;

[0016] One end of the cooling water inlet pipe and one end of the cooling water outlet pipe are respectively connected to the sandwich structure via compression fittings; the other end of the cooling water inlet pipe and the other end of the cooling water outlet pipe are respectively connected to the chiller.

[0017] The cooling water inlet pipe and the cooling water outlet pipe are used to realize the circulation of cooling water in the sandwich structure.

[0018] Optionally, the ultrasonic vibration device includes a piezoelectric transducer and an ultrasonic amplitude transformer;

[0019] The ultrasonic amplitude transformer includes a first end and a second end. The first end of the ultrasonic amplitude transformer is connected to the piezoelectric transducer. The second end of the ultrasonic amplitude transformer extends through the hollow structure and the liquid storage tank to the needle connection port.

[0020] The first end of the ultrasonic amplitude transformer is also connected to the first end of the cooling cylinder via a flange structure.

[0021] Optionally, the ultrasonic amplitude transformer is a cylindrical structure;

[0022] The diameter of the ultrasonic amplitude transformer located inside the hollow structure is D1; ​​the diameter of the ultrasonic amplitude transformer located inside the liquid storage tank is D2; D1>D2.

[0023] Optionally, it also includes a gas transmission pipeline;

[0024] The gas transmission pipeline is connected to the hollow structure via a compression fitting, and is used to introduce gas into the droplet generator or extract gas from the droplet generator.

[0025] Optionally, it also includes pressure sensing lines;

[0026] The pressure detection pipeline is connected to the gas transmission pipeline and is used to detect the pressure in the droplet generator.

[0027] Optionally, it also includes a multi-functional conduit;

[0028] The multifunctional pipe is connected to the hollow structure via a compression fitting, and is used to replenish the working substance in the droplet generator or to detect the temperature of the working substance inside the droplet generator.

[0029] Optionally, it may also include a temperature control module;

[0030] The temperature control module is connected to the heating device and is used to detect and control the heating temperature of the heating device.

[0031] Optionally, a filtering module may also be included;

[0032] One end of the filter module is connected to the bottom of the storage tank, and the other end is connected to the needle connector; it is used to filter the liquid in the storage tank.

[0033] This invention provides a droplet generator. A heating device is annularly arranged on the outer surface of a storage tank, melting the working substance into a liquid. This achieves uniform and continuous heat distribution, avoiding localized overheating or excessive temperature gradients. An ultrasonic vibration device enables a frequency-adjustable droplet sequence at the needle connection port at the bottom of the storage tank. By placing a cooling cylinder between the storage tank and the ultrasonic vibration device, the ultrasonic vibration device is kept away from the high-temperature storage tank, achieving structural decoupling between the vibration transmission path and the heat conduction path. This allows the ultrasonic vibration device to operate at a lower operating temperature for extended periods, effectively preventing performance degradation and depolarization failure caused by high temperatures, significantly improving the reliability and lifespan of the droplet generator. Furthermore, flange connections are used between the ultrasonic vibration device and the cooling cylinder, as well as between the storage tank and the cooling cylinder, allowing for independent disassembly and replacement of each module. Maintenance can be performed without affecting other modules, significantly reducing downtime and maintenance costs.

[0034] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a schematic diagram of the structure of a droplet generator provided in an embodiment of the present invention;

[0037] Figure 2 This is a cross-sectional view of a droplet generator provided in an embodiment of the present invention. Detailed Implementation

[0038] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0039] The terminology used in the embodiments of this invention is for the purpose of describing specific embodiments only and is not intended to limit the invention. It should be noted that directional terms such as "upper," "lower," "left," and "right" described in the embodiments of this invention are used to describe the angles shown in the accompanying drawings and should not be construed as limiting the embodiments of this invention. Furthermore, in the context, it should be understood that when referring to an element being formed "on" or "below" another element, it can be formed not only directly on or below the other element, but also indirectly on or below it through intermediate elements. The terms "first," "second," etc., are used for descriptive purposes only and do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0040] The term "comprising" and its variations as used in this invention are open-ended, meaning "including but not limited to". The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment".

[0041] It should be noted that the concepts of "first" and "second" mentioned in this invention are only used to distinguish the corresponding contents and are not used to limit the order or interdependence.

[0042] It should be noted that the terms "a" and "a plurality of" used in this invention are illustrative rather than restrictive. Those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0043] Figure 1 This is a schematic diagram of a droplet generator provided in an embodiment of the present invention. Figure 2 A cross-sectional view of a droplet generator provided in an embodiment of the present invention is shown below. Figure 1 and Figure 2 As shown, the droplet generator includes a storage tank 1, a heating device 2, a needle connection port 3, an ultrasonic vibration device 4, and a cooling cylinder 5. The storage tank 1 stores the working substance. The heating device 2 is fitted onto the outer surface of the storage tank 1 to heat the working substance, causing it to melt into a liquid. The needle connection port 3 is connected to the bottom of the storage tank 1, allowing the liquid to flow out. The ultrasonic vibration device 4 agitates the liquid in the storage tank 1, causing it to form a droplet sequence at the needle connection port 3. The first end of the cooling cylinder 5 is connected to the ultrasonic vibration device 4 via a flange structure, and the second end of the cooling cylinder 5 is connected to the storage tank 1 via a flange structure, used to reduce the temperature of the ultrasonic vibration device 4.

[0044] like Figure 1 and Figure 2 As shown, the liquid storage tank 1 of the droplet generator is used to store the working substance. Exemplarily, the working substance can be metallic tin, tin-indium alloy, or gallium-indium-tin alloy. When the droplet generator is working, the heating device 2 is fitted onto the outer surface of the liquid storage tank 1 to heat the working substance in the tank, causing it to melt into a liquid. The working substance then flows out from the needle connection port 3 located at the bottom of the liquid storage tank 1. The needle connection port 3 can be a Luer connector to accommodate stainless steel needles or, using an adapter, glass or ceramic needles. This allows for quick connection and switching with various types of external connectors, improving the compatibility of the droplet generator and enabling direct replacement of external connectors, thus enhancing the droplet generator's adaptability to different application scenarios. Exemplarily, the liquid storage tank 1 can be made of austenitic stainless steel, specifically 304 stainless steel and 316 stainless steel.

[0045] Furthermore, to achieve better heating results, the heating device 2 can be a copper heating ring, ceramic heating ring, or aluminum heating ring with a hot runner design, which is fitted onto the outer surface of the liquid storage tank 1 to achieve circumferential heating of the liquid storage tank 1. This avoids direct contact between the heating device 2 and the working substance inside the liquid storage tank 1, fundamentally reducing the risk of contamination and corrosion of the heating device 2, and improving the cleanliness and long-term operational reliability of the droplet generator. In an optional embodiment, thermal conductive paste is also provided in the liquid storage tank 1 and the heating device 2. When the heating device 2 heats the liquid storage tank 1, the thermal conductive paste, in conjunction with the annular design of the heating device 2, can achieve uniform and continuous heat distribution on the outer surface of the liquid storage tank 1, thereby avoiding the problems of local overheating or excessive temperature gradient, ensuring the stable temperature of the molten working substance in the liquid storage tank 1, and maintaining good fluidity and droplet consistency.

[0046] Furthermore, the ultrasonic vibration device 4 is connected to and driven by a signal generator and a signal amplifier, thereby agitating the liquid in the storage tank 1 and causing the liquid in the storage tank 1 to form a droplet sequence at the needle connection port 3. By changing the excitation waveform applied to the ultrasonic vibration device 4 by the signal generator and the signal amplifier, the vibration amplitude and frequency of the ultrasonic vibration device 4 can be adjusted, thereby changing the dropping frequency of the droplet sequence at the needle connection port 3. For example, the operating frequency of the ultrasonic vibration device 4 can be adjusted between 10 kHz and 1 MHz.

[0047] To ensure the fluidity of the liquid in the storage tank 1 during droplet generator operation, the heating device 2 typically keeps the storage tank 1 and its surrounding components operating at a relatively high temperature (approximately 250°C) for extended periods. However, the ultrasonic vibration device 4 generally operates between -40°C and 150°C. Operating in a high-temperature environment will accelerate the performance degradation of the ultrasonic vibration device 4, potentially leading to failure, thus shortening the overall lifespan of the droplet generator and increasing the frequency of system downtime for maintenance. Therefore, if... Figure 1 and Figure 2 As shown, a cooling cylinder 5 is provided between the ultrasonic vibration device 4 and the liquid storage tank 1. The first end of the cooling cylinder 5 is connected to the ultrasonic vibration device 4 via a flange structure, and the second end of the cooling cylinder 5 is connected to the liquid storage tank 1 via a flange structure. The cooling cylinder 5 is used to reduce the temperature of the ultrasonic vibration device 4. For example, the cooling cylinder 5 can be made of 304 stainless steel or 316 stainless steel. The cooling cylinder 5 separates the ultrasonic vibration device 4 and the liquid storage tank 1, avoiding direct contact between them. Simultaneously, the cooling cylinder 5 can cool the heat in the liquid storage tank 1, thereby solving the problem of insufficient operating temperature of the ultrasonic vibration device 4. The droplet generator provided in this embodiment of the invention can cool the temperature of the ultrasonic vibration device 4 to below 50°C at an operating temperature of 250°C.

[0048] This invention, through a ring-shaped heating device on the outer surface of the storage tank, melts the working substance in the tank into a liquid, achieving uniform and continuous heat distribution and avoiding localized overheating or excessive temperature gradients. Using an ultrasonic vibration device, a frequency-adjustable droplet sequence can be obtained at the needle connection port at the bottom of the storage tank. By placing a cooling cylinder between the storage tank and the ultrasonic vibration device, keeping the ultrasonic vibration device away from the high-temperature storage tank, structural decoupling of the vibration transmission path and heat conduction path is achieved. This allows the ultrasonic vibration device to operate at a lower operating temperature for extended periods, effectively preventing performance degradation and depolarization failure caused by high temperatures, significantly improving the reliability and lifespan of the droplet generator. Furthermore, flange connections are used between the ultrasonic vibration device and the cooling cylinder, as well as between the storage tank and the cooling cylinder, allowing for independent disassembly and replacement of each module. Maintenance can be performed without affecting other modules, significantly reducing downtime and maintenance costs.

[0049] Optionally, such as Figure 1 and Figure 2 As shown, the cooling cylinder 5 includes an outer cylindrical wall 51 and an inner cylindrical wall 52. A sandwich structure 53 is formed between the outer cylindrical wall 51 and the inner cylindrical wall 52, and the sandwich structure 53 is filled with cooling water. A hollow structure 54 is formed inside the inner cylindrical wall 52, and the hollow structure 54 is connected to the liquid storage tank 1.

[0050] Specifically, a sealed sandwich structure 53 exists between the outer cylindrical wall 51 and the inner cylindrical wall 52 of the cooling cylinder 5. Cooling water is filled inside the sandwich structure 53. Since the liquid storage tank 1 and the cooling cylinder 5 are connected by a flange structure, when heat is transferred from the liquid storage tank 1 to the cooling cylinder 5, the cooling water within the sandwich structure 53 in the cooling cylinder 5 can carry away the heat. Optionally, as... Figure 1 and Figure 2 As shown, the droplet generator also includes a cooling water inlet pipe 6 and a cooling water outlet pipe 7. One end of the cooling water inlet pipe 6 and one end of the cooling water outlet pipe 7 are respectively connected to the sandwich structure 53 via compression fittings, and the other ends of the cooling water inlet pipe 6 and the cooling water outlet pipe 7 are respectively connected to a chiller. The cooling water inlet pipe 6 and the cooling water outlet pipe 7 are used to circulate the cooling water in the sandwich structure 53. Exemplarily, the compression fitting can also be a vacuum coupling rectangular (VCR) fitting or a quick connect coupling with an O-ring (VCO) fitting, used to achieve a sealed connection between the cooling water inlet pipe 6 and the cooling water outlet pipe 7 and the cooling cylinder 5, ensuring that the cooling water does not overflow when circulating in the sandwich structure 53. Exemplarily, the cooling water can be pure water or coolant.

[0051] This invention, through the installation of a cooling water inlet pipe and a cooling water outlet pipe on the cooling cylinder, and the connection of both pipes to the jacket structure of the cooling cylinder, enables the cooling water to be transferred to and circulated within the jacket structure. This cools the heat transferred from the storage tank to the cooling cylinder. Furthermore, the cooling water circulation speed can be adjusted according to the operating temperature of the storage tank and the operating temperature of the ultrasonic vibration device, thereby regulating the cooling capacity of the cooling cylinder.

[0052] Further reference Figure 1 and Figure 2 The inner cylindrical wall 52 forms a hollow structure 54, which is connected to the liquid storage tank 1. In an optional embodiment, the droplet generator further includes a gas transmission pipeline 8. The gas transmission pipeline 8 is connected to the hollow structure 54 via a compression fitting, and is used to introduce gas into the droplet generator or extract gas from the droplet generator.

[0053] Specifically, the bottom of the liquid storage tank 1 is connected to the vacuum chamber (not shown in the figure) via a flange structure. The needle connection port 3 is located in the vacuum chamber. When the droplet generator is working, gas can be introduced into the hollow structure 54 through the gas transmission pipeline 8. Since the hollow structure 54 is connected to the liquid storage tank 1, a pressure difference will be formed between the liquid storage tank 1 and the vacuum chamber. At this time, the liquid in the liquid storage tank 1 will drip through the needle connection port 3. Furthermore, when adjusting the pressure of the supplied gas, the dripping speed of the droplets at the needle connection port 3 can be adjusted, thereby changing the spacing and size of the droplets. For example, the compression fitting can be a VCR fitting or a VCO fitting, which can withstand a pressure of 30 MPa. The gas entering the droplet generator can be controlled by connecting a high-pressure gas valve, and the pressure range of the gas entering the generator can be between 0.1 MPa and 30 MPa. In addition, the gas transmission pipeline 8 can also be used as a suction port to extract gas from the droplet generator.

[0054] Further reference Figure 1 and Figure 2 In an optional embodiment, the droplet generator further includes a pressure detection line 9. The pressure detection line 9 is connected to the gas transmission line 8 and is used to detect the pressure in the droplet generator.

[0055] Specifically, the pressure sensing line 9 can be connected to a pressure gauge or a pressure transmitter. When gas is introduced into the droplet generator through the gas transmission line 8, since the pressure sensing line 9 is connected to the gas transmission line 8, the pressure of the gas introduced into the droplet generator can be measured through the pressure sensing line 9 when it is connected to the pressure gauge, thereby controlling the droplet emission speed, spacing, and size. When the pressure sensing line 9 is connected to the pressure transmitter, automated pressure data detection can be achieved.

[0056] Optionally, the droplet generator also includes a multi-functional conduit 10. The multi-functional conduit 10 is connected to the hollow structure 54 via a compression fitting for replenishing the working substance into the droplet generator or detecting the temperature of the working substance inside the droplet generator.

[0057] Specifically, such as Figure 1 and Figure 2 As shown, the droplet generator also includes a multi-functional pipe 10. The function of this pipe depends on the module it is connected to and can be modified according to user needs. In one embodiment, since the working substance in the storage tank 1 drips outward through the needle connection port 3 when the droplet generator is working, it is necessary to replenish the working substance in the storage tank 1. In this case, the multi-functional pipe 10 can serve as the inlet for replenishing the working substance, enabling the droplet generator to operate for an extended period. In another embodiment, the multi-functional pipe 10 can also be connected to a thermocouple module to detect the liquid temperature in the storage tank 1.

[0058] This invention, through the installation of a gas transmission pipeline and a multi-functional pipe on the cooling cylinder, connects both to the hollow structure of the cooling cylinder. Since the hollow structure is connected to the liquid storage tank, high-pressure gas can be introduced into the storage tank via the gas transmission pipeline, thereby adjusting the droplet spacing and size at the needle connection point. Furthermore, an access module for the multi-functional pipe can be added as needed, enabling the multi-functional pipe to perform different functions and flexibly adjusting the droplet generator.

[0059] Optionally, such as Figure 1 and Figure 2 As shown, the ultrasonic vibration device 4 includes a piezoelectric transducer 41 and an ultrasonic amplitude transformer 42. The ultrasonic amplitude transformer 42 includes a first end 421 and a second end 422. The first end 421 of the ultrasonic amplitude transformer 42 is connected to the piezoelectric transducer 41, and the second end 422 of the ultrasonic amplitude transformer 42 extends through the hollow structure 54 and the liquid storage tank 1 to the needle connection port 3. The first end 421 of the ultrasonic amplitude transformer 42 is also connected to the first end of the cooling cylinder 5 through a flange structure.

[0060] Specifically, the ultrasonic vibration device 4 consists of a piezoelectric transducer 41 and an ultrasonic amplitude transformer 42, wherein the core of the piezoelectric transducer 41 is a piezoelectric ceramic element. When the droplet generator is working, the driving signal generated by the signal generator and the signal amplifier is applied to the piezoelectric transducer 41, and the vibration excitation generated by the piezoelectric transducer 41 is transmitted through the ultrasonic amplitude transformer 42. The ultrasonic amplitude transformer 42 includes a first end 421 and a second end 422. The first end 421 of the ultrasonic amplitude transformer 42 is connected to the piezoelectric transducer 41, and the connection method can be any one of threaded connection, epoxy resin adhesive connection, or direct welding. When the first end 421 of the ultrasonic amplitude transformer 42 is threadedly connected to the piezoelectric transducer 41, the connection stress between the ultrasonic amplitude transformer 42 and the piezoelectric transducer 41 can be adjusted externally to the droplet generator. When the first end 421 of the ultrasonic amplitude transformer 42 is connected to the piezoelectric transducer 41 through epoxy resin adhesive, since a cooling cylinder 5 is provided between the ultrasonic vibration device 4 and the liquid storage tank 1, there is no need to use high-temperature resistant epoxy resin adhesive.

[0061] Furthermore, such as Figure 1 and Figure 2 As shown, the first end 421 of the ultrasonic amplitude transformer 42 also has a flange structure. The flange structure and the ultrasonic amplitude transformer 42 can be connected by epoxy resin or integrally manufactured. It should be noted that its integral characteristic frequency should meet the frequency requirements of the piezoelectric transducer 41. For example, the flange structure can be made of 304 stainless steel or 316 stainless steel. Furthermore, the first end 421 of the ultrasonic amplitude transformer 42 is connected to the first end of the cooling cylinder 5 through this flange structure, realizing the installation and fixation of the ultrasonic vibration device 4 and the cooling cylinder 5. At the same time, it makes the preload of the ultrasonic vibration device 4 adjustable and can be disassembled and replaced without affecting other functional modules, thereby ensuring the repeatability of vibration transmission conditions, reducing maintenance difficulty and system downtime, and improving the operability of engineering applications.

[0062] Furthermore, the second end 422 of the ultrasonic amplitude transformer 42 extends through the hollow structure 54 and the liquid storage tank 1 to the needle connection port 3. The ultrasonic amplitude transformer 42 contacts the liquid in the liquid storage tank 1. When the vibration excitation generated by the piezoelectric transducer 41 is transmitted to the liquid storage tank 1 through the ultrasonic amplitude transformer 42, Rayleigh rupture occurs in the liquid jet at the needle connection port 3, thereby forming a droplet sequence with stable size and controllable frequency. At the same time, since the hollow structure 54 is surrounded by the sandwich structure 53, the outer periphery of the ultrasonic amplitude transformer 42 in the hollow structure 54 is a ring-shaped water-cooled thermal insulation structure, thus forming a radially high thermal resistance channel. This allows the heat of the liquid storage tank 1 to be preferentially discharged through the water-cooling path rather than conducted upward along the vibration transmission path, thereby achieving the separation of vibration energy conduction and thermal management functions at the structural level.

[0063] In an optional embodiment, the ultrasonic amplitude transformer 42 is a cylindrical structure. The diameter of the ultrasonic amplitude transformer 42 located within the hollow structure 54 is D1, and the diameter of the ultrasonic amplitude transformer 42 located within the liquid storage tank 1 is D2; D1>D2, which increases the vibration amplitude of the ultrasonic amplitude transformer 42, allowing the disturbance generated by the piezoelectric transducer 41 to be transmitted to the needle connection port 3. It is understood that the center of the ultrasonic amplitude transformer 42 should be aligned with the needle connection port 3. Exemplarily, the ultrasonic amplitude transformer 42 can be designed with 304 stainless steel / 316 stainless steel, ceramic, or molybdenum plating.

[0064] This invention connects a piezoelectric transducer to the first end of an ultrasonic amplitude transformer and applies a driving signal to the piezoelectric transducer. Vibration is transmitted and amplified through the ultrasonic amplitude transformer, enabling the vibration excitation to reach the needle connection port. Simultaneously, a flange structure is provided at the first end of the ultrasonic amplitude transformer, connecting the piezoelectric transducer to a cooling cylinder. This cooling cylinder connects the piezoelectric transducer to the liquid reservoir, significantly reducing the actual operating temperature of the piezoelectric transducer while maintaining perturbation efficiency. In other words, this invention effectively decouples the vibration transmission path from the heat conduction path at the structural level, allowing high-frequency perturbation vibration to be stably and efficiently transmitted to the needle connection port. Simultaneously, it significantly suppresses the conduction of high-temperature heat towards the piezoelectric transducer. Therefore, even when the working substance in the liquid reservoir is in a high-temperature melting state, the piezoelectric transducer is maintained in a low-temperature stable operating range, avoiding piezoelectric performance degradation or depolarization failure due to high temperatures, and significantly improving the long-term stability and service life of the droplet generator.

[0065] Optionally, the droplet generator also includes a temperature control module (not shown in the figure). The temperature control module is connected to the heating device 2 and is used to detect and control the heating temperature of the heating device 2. For example, the temperature control module can be a nickel-chromium / nickel-silicon thermocouple (Type K thermocouple). By detecting the temperature of the heating device 2, the temperature control module can achieve precise control of the heating temperature of the heating device 2, thereby achieving temperature control of the working substance in the storage tank 1. Furthermore, the temperature control module can be independently disassembled, making maintenance and replacement easier.

[0066] Optionally, the droplet generator also includes a filter module 11. One end of the filter module 11 is connected to the bottom of the liquid storage tank 1, and the other end is connected to the needle connection port 3. The filter module 11 is used to filter the liquid in the liquid storage tank 1.

[0067] Specifically, one end of the filter module 11 can be connected to the liquid storage tank 1 via a thread, and the other end can be connected to the needle connection port 3 via a thread, welding, or integral manufacturing. Furthermore, a filter screen 12 is also installed inside the filter module 11 to filter the liquid in the liquid storage tank 1. The filtration accuracy of the filter screen 12 can be changed according to the size of the needle connection port 3, generally between 0.2μm and 1μm. For example, the filter module 11 can be made of 304 stainless steel / 316 stainless steel, and the filter screen 12 can be made of stainless steel, ceramic, or silicon carbide sintered mesh.

[0068] When the filter module 11 is connected to the liquid storage tank 1 and the needle connection port 3 by threads, a gasket is usually required for sealing. For example, the gasket can be a stainless steel gasket, a ceramic gasket, or a high-temperature resistant perfluoroether rubber gasket.

[0069] The embodiments of the present invention use a threaded connection to modularly combine the filter module, needle connection port and liquid storage tank. While ensuring sealing and structural strength, it is easy to disassemble, clean or replace the filter screen and needle connection port individually during maintenance, effectively reducing the risk of system failure caused by impurities or blockages and saving maintenance time.

[0070] In summary, this invention, through the modular design of the cooling cylinder, ultrasonic vibration device, filter module, needle connector, heating device, and liquid storage tank, achieves a clear overall structure and well-defined functional boundaries for the droplet generator. Each functional unit can be flexibly combined and replaced according to application requirements. Users can also enhance or modify the droplet generator's functionality based on different application needs, significantly improving its engineering scalability and secondary development capabilities. Furthermore, compared to existing complex vibration coupling schemes, the droplet generator provided by this invention features a simplified structural design, fewer components, and more convenient assembly and debugging, reducing the droplet generator's failure rate and improving overall engineering reliability.

[0071] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, combinations, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A droplet generator, characterized in that, include: Storage tank, used to store working substances; A heating device is fitted onto the outer surface of the liquid storage tank and is used to heat the working substance in the liquid storage tank so that the working substance melts into a liquid. The needle connector is connected to the bottom of the liquid storage tank to allow the liquid in the storage tank to flow out. An ultrasonic vibration device is used to agitate the liquid in the storage tank, causing the liquid in the storage tank to form a sequence of droplets at the needle connection port; A cooling cylinder, the first end of which is connected to the ultrasonic vibration device via a flange structure, and the second end of which is connected to the liquid storage tank via a flange structure, are used to reduce the temperature of the ultrasonic vibration device.

2. The droplet generator according to claim 1, characterized in that, The cooling cylinder includes an outer cylindrical wall and an inner cylindrical wall; A sandwich structure is formed between the outer cylindrical wall and the inner cylindrical wall, and the sandwich structure is filled with cooling water. The inner cylindrical wall has a hollow structure inside, and the hollow structure is connected to the liquid storage tank.

3. The droplet generator according to claim 2, characterized in that, It also includes a cooling water inlet pipe and a cooling water outlet pipe; One end of the cooling water inlet pipe and one end of the cooling water outlet pipe are respectively connected to the sandwich structure via compression fittings; the other end of the cooling water inlet pipe and the other end of the cooling water outlet pipe are respectively connected to the chiller. The cooling water inlet pipe and the cooling water outlet pipe are used to realize the circulation of cooling water in the sandwich structure.

4. The droplet generator according to claim 2, characterized in that, The ultrasonic vibration device includes a piezoelectric transducer and an ultrasonic amplitude transformer. The ultrasonic amplitude transformer includes a first end and a second end. The first end of the ultrasonic amplitude transformer is connected to the piezoelectric transducer. The second end of the ultrasonic amplitude transformer extends through the hollow structure and the liquid storage tank to the needle connection port. The first end of the ultrasonic amplitude transformer is also connected to the first end of the cooling cylinder via a flange structure.

5. The droplet generator according to claim 4, characterized in that, The ultrasonic amplitude transformer is a cylindrical structure; The diameter of the ultrasonic amplitude transformer located inside the hollow structure is D1; ​​the diameter of the ultrasonic amplitude transformer located inside the liquid storage tank is D2; D1>D2.

6. The droplet generator according to claim 2, characterized in that, It also includes gas transmission pipelines; The gas transmission pipeline is connected to the hollow structure via a compression fitting, and is used to introduce gas into the droplet generator or extract gas from the droplet generator.

7. The droplet generator according to claim 6, characterized in that, It also includes pressure detection piping; The pressure detection pipeline is connected to the gas transmission pipeline and is used to detect the pressure in the droplet generator.

8. The droplet generator according to claim 2, characterized in that, It also includes multi-functional pipes; The multifunctional pipe is connected to the hollow structure via a compression fitting, and is used to replenish the working substance in the droplet generator or to detect the temperature of the working substance inside the droplet generator.

9. The droplet generator according to claim 1, characterized in that, It also includes a temperature control module; The temperature control module is connected to the heating device and is used to detect and control the heating temperature of the heating device.

10. The droplet generator according to claim 1, characterized in that, It also includes a filtering module; One end of the filter module is connected to the bottom of the storage tank, and the other end is connected to the needle connector; it is used to filter the liquid in the storage tank.

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