Single crystal furnace for growing neodymium-doped yttrium lithium fluoride

Abstract

The utility model relates to a single crystal furnace for growing neodymium-doped yttrium lithium fluoride, and belongs to the technical field of preparation of yttrium lithium fluoride crystals. The single crystal furnace for growing neodymium-doped yttrium lithium fluoride comprises a furnace body, a crucible arranged in the furnace body and a temperature adjusting system used for heating the crucible, the crucible is used for containing raw materials of neodymium-doped yttrium lithium fluoride, and a pulling system used for pulling the neodymium-doped yttrium lithium fluoride is arranged at the top of the furnace body. A liquid cooling system is arranged on the side wall of the furnace body, and an anti-fluorine coating is arranged on the surface of a hearth of the furnace body. In the growth process of yttrium lithium fluoride crystals, epoxy resin, polytetrafluoroethylene and other materials are adopted, and the fluorine-proof coating is arranged in the hearth of the single crystal furnace, so that the hearth and a liquid cooling system are prevented from being eroded by fluorine-containing protective gas, and the condition that neodymium-doped yttrium lithium fluoride raw materials and thermal insulation materials are polluted due to liquid leakage of the hearth is prevented.

Description

Technical Field

[0001] The utility model belongs to the technical field of yttrium lithium fluoride crystal preparation, and particularly relates to a single crystal furnace for growing neodymium-doped yttrium lithium fluoride. Background Art

[0002] The Nd:YLF crystal plays an important role in the current laser ignition device and is one of the key core components required for establishing a laser inertial confinement fusion ignition device. Among them, Nd:YLF is the abbreviation of neodymium-doped yttrium lithium fluoride.

[0003] The existing single crystal furnace for yttrium lithium fluoride uses high-purity argon and carbon tetrafluoride as protective gases. In this atmosphere, hydrofluoric acid (fluoric acid) is easily generated. Low-concentration hydrofluoric acid is a weak acid, but it has extremely strong corrosiveness and can corrode metals violently. In the case where stainless steel is sensitized due to welding or other reasons, fluoride ions will cause local corrosion. When the stainless steel is in a heating state with a temperature range of 500°C to 850°C and exceeds the bearing time, chromium carbides will be formed at the crystal grain boundaries of the stainless steel, and there will be a phenomenon of forming a chromium-deficient layer near the grain boundaries. The service cycle of the single crystal furnace, repeated heating and cooling, will cause the leakage of water at the welded joints of the single crystal furnace to accelerate. In the existing single crystal furnace for growing oxides, the stainless steel furnace chamber is not protected against growing fluoride crystals, and long-term operation will further shorten the service life of the furnace chamber. The Nd:YLF raw material is expensive. When water leaks in the furnace chamber, the raw material and the thermal insulation material will be contaminated and discarded, resulting in huge economic losses. Summary of the Utility Model

[0004] The purpose of the utility model is to provide a single crystal furnace for growing neodymium-doped yttrium lithium fluoride to solve the above problems. The furnace chamber of the single crystal furnace has anti-fluorine characteristics, can avoid the phenomenon of liquid leakage inside the furnace chamber, and reduce the risk of contamination of the neodymium-doped yttrium lithium fluoride crystal.

[0005] The utility model realizes the above purpose through the following technical solutions:

[0006] A single crystal furnace for growing neodymium-doped yttrium lithium fluoride includes a furnace body, a crucible disposed inside the furnace body, and a temperature control system for heating the crucible. The crucible is used to contain the raw material of neodymium-doped yttrium lithium fluoride. A lifting system for lifting the neodymium-doped yttrium lithium fluoride is provided at the top of the furnace body. A liquid cooling system is provided on the side wall of the furnace body, and an anti-fluoride coating is provided on the surface of the furnace chamber of the furnace body. During the crystal growth process, the raw material of neodymium-doped yttrium lithium fluoride in the crucible is heated to a molten state by the temperature control system. The output end of the lifting system extends into the crucible, rotates and lifts upward, so that the raw material of neodymium-doped yttrium lithium fluoride continuously grows below the output end of the lifting system. The furnace body is cooled by the liquid cooling system to make the temperature field distribution in the furnace chamber of the furnace body reasonable. By providing an anti-fluoride coating in the furnace chamber, the furnace body and the liquid cooling system in the furnace body are prevented from being eroded by the fluoride-containing protective gas, and the raw material of neodymium-doped yttrium lithium fluoride and the thermal insulation material are prevented from being polluted due to liquid leakage in the furnace chamber.

[0007] As a further optimized solution of the present invention, the anti-fluoride coating is divided into a first coating and a second coating. The materials of the first coating and the second coating are both epoxy resin or both polytetrafluoroethylene, and a heat insulation plate is provided at the top inside the furnace body.

[0008] As a further optimized solution of the present invention, the furnace body includes an inner furnace body and an outer furnace body. The liquid cooling system includes a water pump, a water tank communicated with the water pump, and a liquid cooling pipe with two ends respectively communicated with the water pump and the water tank. The liquid cooling pipe is coiled between the inner furnace body and the outer furnace body.

[0009] As a further optimized solution of the present invention, the liquid leakage detection system includes an annular water absorption component provided on the surface of the anti-fluoride coating, a first electrode and a second electrode connected to the water absorption component, and a controller. The water absorption component is used to absorb the coolant leaked from the outside of the liquid cooling system to make the first electrode and the second electrode conduct. The controller is used to detect the conduction condition of the first electrode and the second electrode. The liquid leakage detection system is used to detect the liquid leakage situation in the furnace chamber. When the liquid leakage detection system detects liquid leakage in the furnace chamber, an alarm is sent to the computer terminal or the mobile terminal carried by the staff to remind the staff to come and troubleshoot.

[0010] As a further optimized solution of the present invention, a solenoid valve is provided at the water outlet of the water tank, and the liquid cooling pipe is communicated with the water outlet of the water tank through the solenoid valve. When the controller detects that the first electrode and the second electrode conduct, the solenoid valve closes.

[0011] As a further optimized solution of the present invention, a liquid leakage detection system is provided on the side wall of the furnace body. The liquid leakage detection system further includes an inner conductive ring and an outer conductive ring. A plurality of first electrodes are arranged circumferentially along the inner conductive ring, and a plurality of second electrodes are arranged circumferentially along the outer conductive ring. The controller is electrically connected to the first electrode and the second electrode through the inner conductive ring and the outer conductive ring respectively.

[0012] As a further optimized solution of the present utility model, the liquid cooling system further includes a heat dissipation pipe disposed between the water pump outlet and the water tank inlet, and a radiator and a fan are provided on the water tank, and the middle part of the heat dissipation pipe is circuitously disposed on the radiator.

[0013] As a further optimized solution of the present utility model, a supply and exhaust pipe is provided on one side of the furnace body, and the supply and exhaust pipe is connected to a vacuum system.

[0014] As a further optimized solution of the present utility model, the supply and exhaust pipe includes a side pipe penetrating through the side walls of the inner furnace body and the outer furnace body, an air inlet is provided at the top of the side pipe, and an exhaust port is provided at the end of the side pipe.

[0015] As a further optimized solution of the present utility model, the temperature regulation system includes an induction coil disposed outside the crucible, a first temperature sensor disposed on one side of the furnace body, a second temperature sensor disposed on the side pipe, and a heating component disposed inside the side pipe.

[0016] The beneficial effects of the present utility model are as follows:

[0017] 1) During the growth process of the yttrium lithium fluoride crystal of the present utility model, materials such as epoxy resin and polytetrafluoroethylene are used to set an anti-fluoride coating in the furnace chamber of the single crystal furnace to prevent the furnace chamber and the liquid cooling system from being eroded by the fluoride-containing protective gas, and to prevent the situation that the neodymium-doped yttrium lithium fluoride raw material and the thermal insulation material are polluted due to liquid leakage in the furnace chamber;

[0018] 2) The anti-fluoride coating provided in the furnace chamber of the present utility model is divided into a first coating and a second coating, and the thickness of each layer of the coating is 4-6 filaments. The double-layer anti-fluoride coating can improve the firmness of the coating itself, so that the anti-fluoride coating is not easily peeled off. The double-layer anti-fluoride coating has a moderate thickness, avoiding the decrease of the thermal conductivity due to too thick coating, so as not to interfere with the liquid cooling system. Since the temperature above the single crystal furnace is relatively high, a heat insulation board is provided at the top of the furnace chamber to prevent the anti-fluoride coating at the top of the furnace chamber from overheating and peeling off;

[0019] 3) The present utility model is provided with a liquid leakage detection system to detect whether there is a liquid leakage phenomenon in the furnace chamber. If the furnace chamber leaks liquid, it will remind the staff to come for troubleshooting. At the same time, the solenoid valve at the water tank outlet is closed, and the coolant in the liquid cooling pipe is pumped into the water tank by the water pump;

[0020] 4) The present utility model is provided with temperature sensors on the furnace body and the supply and exhaust pipe to detect whether there is an abnormal temperature condition at the side pipe for adjusting the protective atmosphere and the vacuum degree, and the temperature of the side pipe is adjusted by the heating component inside the side pipe to make the temperature gradient around the crucible reasonably distributed. Description of the Drawings

[0021] Figure 1It is a schematic diagram of the overall structure of the present utility model;

[0022] Figure 2 It is a schematic front view structure diagram of the present utility model;

[0023] Figure 3 It is Figure 2 an enlarged view of part A in

[0024] Figure 4 It is Figure 2 an enlarged view of part B in

[0025] Figure 5 It is a top view structure diagram of the liquid leakage detection system of the present utility model.

[0026] In the figure: 1, furnace body; 11, inner furnace body; 12, outer furnace body; 13, observation hole; 2, crucible; 3, temperature regulation system; 31, induction coil; 32, first temperature sensor; 33, second temperature sensor; 34, heating component; 4, lifting system; 41, upper cylinder; 42, lifting mechanism; 43, rotating mechanism; 44, seed crystal rod; 5, liquid cooling system; 51, water pump; 52, water tank; 53, liquid cooling pipe; 54, solenoid valve; 55, heat dissipation pipe; 56, radiator; 57, fan; 6, anti-fluoride coating; 61, first coating; 62, second coating; 7, liquid leakage detection system; 71, water absorption component; 72, first electrode; 73, second electrode; 74, controller; 75, inner conductive ring; 76, outer conductive ring; 8, supply and exhaust pipe; 81, side pipe; 82, air inlet; 83, exhaust port; 84, electrical feedthrough; 9, vacuum system; 91, vacuum pump; 92, vacuum valve; H, heat insulation board. Specific embodiments

[0027] The following further describes the present application in detail with reference to the accompanying drawings. It is necessary to point out here that the following specific embodiments are only used to further illustrate the present application and cannot be understood as limiting the protection scope of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content.

[0028] Experiment 1

[0029] First, an epoxy resin coating is set on a stainless steel plate. In the experiment, four stainless steel plates with the same material as the inner furnace body 11 are used. The specifications of the plates are: 20mm x 30mm, and the thickness is 6mm. Prepare a two-component epoxy resin glue diluent, and brush the two-component epoxy resin glue diluent onto the surface of the stainless steel plate with a brush with a width of 20mm.

[0030] Apply a layer of diluent on the first sheet of board and two layers of diluent on the second sheet of board. It is found that during the continuous application of diluent on the second sheet of board, the diluent is uneven. Therefore, wash the diluent on the second sheet of board and reapply the diluent. During this period, after the upper layer of diluent solidifies, then apply the next layer of diluent. And so on, apply three layers and four layers of diluent on the third and fourth sheets of board respectively.

[0031] The curing time is 24 hours. After each sheet of board is cured, conduct a fluorination test. Put the four sheets of board into a hydrofluoric acid solution (concentration 10%) diluted with deionized water. About 1000 ml of the solution is heated to about 100 degrees in a stainless steel tank, and always keep the exhaust on to prevent safety hazards. Take them out after 2 hours, rinse, dry and observe. No obvious fluorination marks are found on the surface.

[0032] Experiment Two

[0033] Set up an epoxy resin coating on the stainless steel sheet in the way of Experiment One. After each sheet of board is cured, conduct a fluorination test. Put the four sheets of board into a hydrofluoric acid solution (concentration 10%) diluted with deionized water and heat to about 100 degrees. About 3000 ml of the solution is heated in a stainless steel tank. Always keep the exhaust on to prevent safety hazards. Take them out after 5 hours, rinse, dry and observe. No obvious fluorination marks are found on the surface.

[0034] Experiment Three

[0035] Measure the thickness of the epoxy resin coating on each sheet of board in Experiment Two. The thickness of one layer is 4 - 5 filaments, the thickness of two layers is 10 filaments, the thickness of three layers is 15 filaments, and the thickness of four layers is 20 filaments. The multi-layer epoxy resin coating is prone to the phenomenon of uneven coating thickness. Scratch with a knife and find that the firmness of the one-layer epoxy resin coating is poor, and the firmness of the four-layer is the best.

[0036] Experiment Four

[0037] Use an alcohol lamp to roast to detect the heat resistance of the epoxy resin coating. The heat resistance of the one-layer epoxy resin coating is poor, the heat resistance of the two-layer and three-layer epoxy resin coatings is better, and the heat resistance of the four-layer epoxy resin coating is the best, but the heat conduction is the worst. Based on the comprehensive evaluation results, applying two layers of 10-filament epoxy resin coating on the surface of the stainless steel sheet has the best protection effect and heat conduction effect.

[0038] Experiment Five

[0039] The furnace chamber of the single crystal furnace is first cleaned with absolute ethanol and then wiped clean with ether. The parts that need to be protected are brushed with a two-component epoxy resin glue diluent. After curing for 24 hours, it is polished flat, cleaned with absolute ethanol, then applied the second time. After curing for 24 hours, it is wiped clean and then ready to be installed in the furnace for use. During the experiment, it was found that the upper part of the longitudinal temperature field (at the single crystal pulling opening) directly faces the top of the furnace chamber, and the temperature is the highest. After long-term baking, the epoxy resin protective layer may age and peel off.

[0040] Experiment Six

[0041] A 1-mm-thick stainless steel heat insulation plate H is installed on the inner top of the furnace chamber of the single crystal furnace. The diameter of the heat insulation plate H is 450 mm, and the diameter of the central through hole is 30 mm (the diameter of the seed crystal rod hole). Four stainless steel fixing screws (with a diameter of 6 mm) are welded to the inner top of the furnace chamber by argon arc welding. Holes are drilled at the corresponding positions of the heat insulation plate H. The heat insulation plate H is 50 mm away from the inner top of the furnace chamber. If the distance is too large, it will affect the pulling stroke of the crystal and the equal diameter length will be insufficient. The fixing screws need to be locked with double nuts to prevent loosening and peeling. The heat insulation plate H does not need to be protected. After five growth cycles, the inner wall of the furnace chamber is still as smooth and intact as before. The heat dissipation of the furnace chamber is normal. It is concluded from long-term operation that for the lifespan of the anti-fluoride coating 6 (the peeling time between the anti-fluoride coating 6 and the furnace wall), before spraying the furnace wall, the roughness and cleanliness of the treated surface must be well controlled.

[0042] Through the protection design and transformation of the single crystal furnace and the furnace chamber, the lack of a dedicated crystal growth furnace for growing fluoride crystals has been changed. It provides the most basic guarantee for growing large-size fluoride crystals, ensuring that the single crystal furnace and the furnace chamber will not cause raw material pollution due to fluoride leakage and can be used with confidence for a long time.

[0043] Examples

[0044] Such as Figure 1 And Figure 2As shown in the figure, a single crystal furnace for growing neodymium-doped yttrium lithium fluoride includes a furnace body 1, a crucible 2 arranged inside the furnace body 1, and a temperature regulation system 3 for heating the crucible 2. The crucible 2 is used to contain the raw material of neodymium-doped yttrium lithium fluoride. A lifting system 4 for lifting neodymium-doped yttrium lithium fluoride is provided at the top of the furnace body 1. A liquid cooling system 5 is provided on the side wall of the furnace body 1, and an anti-fluoride coating 6 is provided on the inner surface of the furnace chamber of the furnace body 1. During the crystal growth process, the raw material of neodymium-doped yttrium lithium fluoride in the crucible 2 is heated to a molten state by the temperature regulation system 3. The lifting system 4 extends its output end into the crucible 2 to rotate and lift the raw material of neodymium-doped yttrium lithium fluoride upward, so that the raw material of neodymium-doped yttrium lithium fluoride continuously grows below the output end of the lifting system 4. The furnace body 1 is cooled by the liquid cooling system 5 to make the temperature field distribution in the furnace chamber of the furnace body 1 reasonable. By providing the anti-fluoride coating 6 in the furnace chamber, the furnace body 1 and the liquid cooling system 5 in the furnace body 1 are prevented from being eroded by the fluoride-containing protective gas, avoiding the pollution of the raw material of neodymium-doped yttrium lithium fluoride and the thermal insulation material due to liquid leakage in the furnace chamber. The fluoride-containing protective gas includes carbon tetrafluoride gas.

[0045] Specifically, please refer to 2 and Figure 3 , the anti-fluoride coating 6 is divided into a first coating 61 and a second coating 62. The materials of the first coating 61 and the second coating 62 are both epoxy resin. The thickness of each epoxy resin coating is 4 to 6 filaments. The double-layer anti-fluoride coating 6 can improve the firmness of the coating itself, so that the anti-fluoride coating 6 is not easily peeled off. The double-layer anti-fluoride coating 6 has a moderate thickness, avoiding the decrease in thermal conductivity caused by too thick a coating, so as not to interfere with the liquid cooling system 5. Since the temperature above the furnace body 1 is relatively high, a heat insulation plate H is provided at the inner top of the furnace body 1. In addition, the materials of the first coating 61 and the second coating 62 of the anti-fluoride coating 6 can also be replaced with polytetrafluoroethylene. The lifting system 4 includes an upper cylinder body 41 fixedly arranged at the top of the furnace body 1. A lifting mechanism 42 is fixedly arranged at the top of the upper cylinder body 41. The output end of the lifting mechanism 42 is fixedly provided with a rotating mechanism 43. A seed crystal rod 44 is provided at the output end of the rotating mechanism 43. Through holes corresponding to the seed crystal rod 44 are opened on both the furnace body 1 and the heat insulation plate H.

[0046] As Figure 2As shown, the furnace body 1 includes an inner furnace body 11 and an outer furnace body 12. The furnace surface of the furnace body 1 is the inner sidewall of the inner furnace body 11. The material of the inner furnace body 11 is preferably stainless steel. An observation hole 13 is provided through the furnace body 1, and a heat-insulating observation window is provided in the observation hole 13. The material of this observation window is preferably corundum. The observation hole 13 can be provided on the side or the top of the furnace body 1. If the observation hole 13 is provided on the top of the furnace body 1, an observation window needs to be correspondingly opened on the heat-insulating plate H, and a corundum heat-insulating layer is filled in this window. A heat-insulating material (not shown in the figure) is also provided between the inner furnace body 11 and the crucible 2. The liquid cooling system 5 includes a water pump 51, a water tank 52 communicated with the water pump 51, and a liquid cooling pipe 53 with two ends respectively communicated with the water pump 51 and the water tank 52. The liquid cooling pipe 53 is coiled between the inner furnace body 11 and the outer furnace body 12. The water tank 52 is used to store the coolant, and the coolant is preferably a conductive water body.

[0047] As Figure 2 and Figure 5 shown, a liquid leakage detection system 7 is provided on the sidewall of the furnace body 1. The liquid leakage detection system 7 is used to detect the liquid leakage situation in the furnace chamber. When the liquid leakage detection system 7 detects liquid leakage in the furnace chamber, it sends an alarm to the computer terminal or the mobile terminal carried by the staff to remind the staff to come and troubleshoot. Specifically, the liquid leakage detection system 7 includes an annular water-absorbing component 71 provided on the surface of the anti-fluoride coating 6, a first electrode 72 and a second electrode 73 connected to the water-absorbing component 71, and a controller 74. The water-absorbing component 71 is used to absorb the coolant leaked from the liquid cooling system 5 to make the first electrode 72 and the second electrode 73 conduct. The controller 74 is used to detect the conduction condition between the first electrode 72 and the second electrode 73. The preferred installation position of the water-absorbing component 71 is the bottom of the furnace chamber. The water-absorbing component 71 can also be laid on the entire surface of the anti-fluoride coating 6. In addition to conducting the first electrode 72 and the second electrode 73, the water-absorbing component 71 can also block and absorb the coolant leaked from the liquid cooling system 5 to prevent the coolant from directly spraying near the crucible 2 when it leaks. The water-absorbing component 71 is nano-zeolite. Both the first electrode 72 and the second electrode 73 are electrically connected to the water-absorbing component 71 through wires wrapped with insulating layers.

[0048] When the coolant of the liquid cooling pipe 53 leaks outside into the furnace chamber, the water-absorbing component 71 conducts electricity, making the first electrode 72 and the second electrode 73 conduct. The controller 74 detects whether the circuit between the first electrode 72 and the second electrode 73 is conducting, so as to judge whether there is a liquid leakage phenomenon in the furnace chamber. The controller 74 is connected to a computer terminal or a mobile terminal. When a liquid leakage phenomenon occurs, the controller 74 sends an alarm to the computer terminal or the mobile terminal to remind the staff to come and troubleshoot.

[0049] Preferably, please refer to Figure 2, a solenoid valve 54 is provided at the water outlet of the water tank 52, and the liquid cooling pipe 53 is communicated with the water outlet of the water tank 52 through the solenoid valve 54. When the controller 74 detects that the first electrode 72 and the second electrode 73 are conducting, the solenoid valve 54 is closed, and the coolant in the liquid cooling pipe 53 is pumped into the water tank 52 by the water pump 51. The liquid leakage detection system 7 further includes an inner conductive ring 75 and an outer conductive ring 76. A plurality of first electrodes 72 are arranged circumferentially along the inner conductive ring 75, and a plurality of second electrodes 73 are arranged circumferentially along the outer conductive ring 76. The controller 74 is electrically connected to the first electrode 72 and the second electrode 73 through the inner conductive ring 75 and the outer conductive ring 76 respectively. Specifically, as Figure 5 shown, the inner conductive ring 75 and the outer conductive ring 76 are respectively connected to the low-level pin and the high-level pin of the controller 74. When the first electrode 72 and the second electrode 73 are conducting, the potential at the high-level pin of the controller 74 is pulled down, so as to realize the detection of the conduction state of the two electrodes 72 and 73. In addition, the conduction state of the first electrode 72 and the second electrode 73 can also be detected by setting an ammeter on the line between the two electrodes 72 and 73. If it is conducting, the ammeter feeds back a signal to the controller 74, so as to realize the detection of the conduction state of the first electrode 72 and the second electrode 73. By setting a plurality of first electrodes 72 connected in parallel with each other and a plurality of second electrodes 73 connected in parallel with each other, the detection efficiency can be improved. When the water absorption part 71 absorbs water and conducts electricity at the part between the adjacent first electrode 72 and the second electrode 73, the detection of the liquid leakage phenomenon can be realized, and the risk of the neodymium-doped yttrium lithium fluoride raw material and the thermal insulation material being polluted can be further reduced.

[0050] Furthermore, as Figure 2 and Figure 4As shown, the liquid cooling system 5 further includes a heat dissipation pipe 55 disposed between the water outlet of the water pump 51 and the water inlet of the water tank 52, and a radiator 56 and a fan 57 are provided on the water tank 52. The middle part of the heat dissipation pipe 55 is circuitously arranged on the radiator 56, and the heat of the coolant in the heat dissipation pipe 55 is reduced by the cooperation of the fan 57 and the radiator 56. On one side of the furnace body 1, there is a supply and exhaust pipe 8, and the supply and exhaust pipe 8 is connected to a vacuum system 9. The vacuum system 9 includes a vacuum pump 91 and a vacuum valve 92 disposed between the vacuum pump 91 and the side pipe 81. The supply and exhaust pipe 8 includes a side pipe 81 penetrating through the side walls of the inner furnace body 11 and the outer furnace body 12. An air inlet 82 is provided at the top of the side pipe 81, and an exhaust port 83 is provided at the end of the side pipe 81. The air inlet 82 is used for cleaning the furnace chamber and introducing a protective gas, and exhausts through the exhaust port 83 after the growth is completed. The temperature regulation system 3 includes an induction coil 31 disposed outside the crucible 2, a first temperature sensor 32 disposed on the side of the furnace body 1 opposite to the side pipe 81, a second temperature sensor 33 disposed on the side pipe 81, and a heating component 34 disposed inside the side pipe 81. Both the first temperature sensor 32 and the second temperature sensor 33 are connected to the controller 74. The models of the first temperature sensor 32 and the second temperature sensor 33 are preferably PL7101. An electrical feedthrough 84 for connecting the lead-in wire and the lead-out wire of the induction coil 31 is provided at the end of the side pipe 81. The temperature regulation system 3 performs induction heating on the crucible 2 through the induction coil 31. The heating component 34 is preferably a frame structure with heating wires. When the difference between the temperatures measured by the second temperature sensor 33 and the first temperature sensor 32 reaches a set value, the side pipe 81 is heated through the heating component 34 to make the temperature field distribution on both sides of the crucible 2 balanced.

[0051] The above embodiments only represent several implementation manners of the present invention, and their descriptions are relatively specific and detailed, but should not be construed as limiting the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention.

Claims

1. A single crystal furnace for growing Nd-doped lithium yttrium fluoride, comprising a furnace body (1), a crucible (2) arranged inside the furnace body (1), and a temperature regulating system (3) for heating the crucible (2), wherein the crucible (2) is used to contain the raw material of the Nd-doped lithium yttrium fluoride, and a pulling system (4) for pulling the Nd-doped lithium yttrium fluoride is provided on the top of the furnace body (1), characterized in that: A liquid cooling system (5) and a liquid leakage detection system (6) are provided on the side wall of the furnace body (1), and a fluorine-proof coating (7) is provided on the furnace chamber surface of the furnace body (1).

2. The single crystal furnace for growing Nd:Yttrium fluoride-doped lithium crystal according to claim 1, characterized in that: The anti-fluorine coating (7) is divided into a first coating (71) and a second coating (72); the first coating (71) and the second coating (72) are both made of epoxy resin or polytetrafluoroethylene; a heat insulation board (H) is provided on the top of the inner side of the furnace body (1).

3. The single crystal furnace for growing Nd:Yttrium fluoride-doped lithium crystal according to claim 1, characterized in that: The furnace body (1) comprises an inner furnace body (11) and an outer furnace body (12); the liquid cooling system (5) comprises a water pump (51), a water tank (52) connected to the water pump (51), and a liquid cooling pipe (53) whose two ends are respectively connected to the water pump (51) and the water tank (52); the liquid cooling pipe (53) is coiled between the inner furnace body (11) and the outer furnace body (12).

4. The single crystal furnace for growing Nd:Yttrium fluoride-doped lithium crystal according to claim 3, characterized in that: The liquid leakage detection system (6) comprises an annular water absorbing component (61) arranged on the surface of the anti-fluorine coating (7), a first electrode (62) and a second electrode (63) connected to the water absorbing component (61), and a controller (64). The water absorbing component (61) is used to absorb the cooling liquid leaked from the liquid cooling system (5) so that the first electrode (62) and the second electrode (63) are conductive, and the controller (64) is used to detect the conductive state of the first electrode (62) and the second electrode (63).

5. The single crystal furnace for growing Nd:Yttrium fluoride-doped lithium crystal according to claim 4, characterized in that: The water outlet of the water tank (52) is provided with a solenoid valve (54), and the liquid cooling pipe (53) is connected to the water outlet of the water tank (52) through the solenoid valve (54). When the controller (64) detects that the first electrode (62) and the second electrode (63) are connected, the solenoid valve (54) is closed.

6. The single crystal furnace for growing Nd:Yttrium-doped lithium fluoride according to claim 5, characterized in that: The liquid leakage detection system (6) further comprises an inner conductive ring (65) and an outer conductive ring (66); a plurality of the first electrodes (62) are arranged along the circumference of the inner conductive ring (65); a plurality of the second electrodes (63) are arranged along the circumference of the outer conductive ring (66); and the controller (64) is electrically connected to the first electrode (62) and the second electrode (63) via the inner conductive ring (65) and the outer conductive ring (66), respectively.

7. The single crystal furnace for growing Nd:Yttrium fluoride-doped lithium crystal according to claim 5, characterized in that: The liquid cooling system (5) further comprises a heat dissipation pipe (55) arranged between a water outlet of a water pump (51) and a water inlet of a water tank (52), and a radiator (56) and a fan (57) are arranged on the water tank (52), and the middle portion of the heat dissipation pipe (55) is arranged on the radiator (56) in a circuitous manner.

8. The single crystal furnace for growing Nd:Yttrium fluoride-doped lithium crystal according to claim 5, characterized in that: An air supply and exhaust pipe (8) is provided on one side of the furnace body (1), and the air supply and exhaust pipe (8) is connected to a vacuum system (9).

9. The single crystal furnace for growing Nd:Yttrium fluoride-doped lithium crystal according to claim 8, characterized in that: The air supply and exhaust pipe (8) comprises a side pipe (81) penetrating the side walls of the inner furnace body (11) and the outer furnace body (12); an air inlet (82) is provided at the top of the side pipe (81), and an air outlet (83) is provided at the end of the side pipe (81).

10. The single crystal furnace for growing Nd:Yttrium-doped lithium fluoride according to claim 9, characterized in that: The temperature regulating system (3) comprises an induction coil (31) arranged outside the crucible (2), a first temperature sensor (32) arranged on one side of the furnace body (1), a second temperature sensor (33) arranged on the side tube (81), and a heating component (34) arranged inside the side tube (81).

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