Intraocular lens continuous feeding device and intraocular lens continuous preparation method

Abstract

The invention relates to an intraocular lens continuous feeding device and an intraocular lens continuous preparation method, the intraocular lens continuous feeding device comprises a melting furnace, a growth furnace, a conveying pipe communicating the melting furnace and the growth furnace, and a controller, the top of the melting furnace is provided with a feeding part, and the feeding part is provided with an on-off valve; a liquid level measuring structure is arranged in the growth furnace, a lifting rod is rotationally arranged at the top of the growth furnace, and the cross section of an inner cavity of the growth furnace is circular; the bottoms of the inner cavity of the melting furnace and the inner cavity of the growing furnace are arranged in an equal plane, the conveying pipe horizontally extends and is connected to the bottoms of the side walls of the melting furnace and the growing furnace, so that a communicating vessel structure is formed inside the melting furnace and the growing furnace, and the extending direction of the conveying pipe is tangent to the outmost outline of the inner cavity of the growing furnace, so that mixed liquid enters the growing furnace in the tangential direction; and the controller is in sampling connection with the liquid level measuring structure and is in control connection with the on-off valve. The stability of the molten liquid in the lifting growth furnace is kept, and the purpose of industrially and continuously growing high-quality large-size crystals is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of artificial crystal preparation, in particular to an artificial crystal continuous feeding device and an artificial crystal continuous preparation method. BACKGROUND

[0002] The preparation method of artificial crystal generally includes the Czochralski method, the hydrothermal method and the vapor deposition method, and the Czochralski method is a method widely used for growing high-quality single crystals, and is particularly suitable for preparing crystals with high melting point and good mechanical properties, such as lithium niobate (LiNbO3), lithium tantalate (LiTaO3) and silicon single crystals. In the prior art, the growth furnace for preparing artificial crystals by the Czochralski method is manually operated. To prepare large-size single crystals, a larger-size crucible must be used, and the raw materials are loaded into the crucible at one time before melting. Since continuous feeding cannot be achieved, the crystal production efficiency is affected, and during the crystal growth process, the composition of the crystal melt in the growth furnace usually changes with the progress of crystal preparation. If the feeding is not timely, the crystal quality will be affected. In addition, the solid-liquid interface shape is unstable during the crystal growth process, and the position changes with the crystal growth, which is not conducive to obtaining high-quality large-size artificial crystals. SUMMARY

[0003] The present application aims to provide an artificial crystal continuous feeding device to solve the problem of one-time feeding in the prior art, which leads to the inability to feed during the crystal growth process and unstable liquid level; and the present application also aims to provide an artificial crystal continuous preparation method.

[0004] To solve the above problems, the artificial crystal continuous feeding device according to the present application adopts the following technical scheme:

[0005] The artificial crystal continuous feeding device comprises a melting furnace and a growth furnace, a conveying pipe connecting the melting furnace and the growth furnace, and a controller, wherein: the top of the melting furnace is provided with a feeding part, and the feeding part is provided with an on-off valve;

[0006] The growth furnace is provided with a liquid level measuring structure, the top of the growth furnace is provided with a rotationally arranged pulling rod, and the inner cavity of the growth furnace is circular in cross section;

[0007] The inner cavities of the melting furnace and the growth furnace are arranged in a horizontal plane, the conveying pipe is horizontally extended and connected to the bottom of the side wall of the melting furnace and the growth furnace to form an equal-liquid-level communicating vessel structure in the interiors of the melting furnace and the growth furnace, and

[0008] The extension direction of the conveying pipe is tangentially arranged with the outermost profile of the inner cavity of the growth furnace to make the mixed liquid enter the growth furnace along the tangential direction;

[0009] The controller is connected with the liquid level measuring structure and connected with the on-off valve control to control the on-off valve to keep the liquid level in the growth furnace in dynamic balance after the liquid level in the growth furnace drops and rises to a set threshold.

[0010] Further, the rotation direction of the pulling rod is the same as the flow direction of the mixed liquid entering the growth furnace.

[0011] Further, the feeding part comprises a feeding pipe arranged at the top of the melting furnace, and a cooling water channel is arranged on the outer wall of the feeding pipe.

[0012] Further, the feeding pipe comprises vertical sections at two ends and an inclined section connecting the two vertical sections, so that the feeding pipe is formed into a Z-shaped pipe structure.

[0013] Further, a gas lance is arranged on the side wall of the feeding pipe to introduce inert gas into the feeding pipe, the nozzle of the gas lance is located above the inclined section, and the jet direction extends obliquely downward toward the upper side wall of the inclined section.

[0014] Further, the liquid level measuring structure comprises a laser range finder arranged on the top wall of the growth furnace, and the laser emission path of the laser range finder is perpendicular to the liquid level of the growth furnace.

[0015] Further, the melting furnace and the growth furnace each comprise a crucible and a material heating structure arranged outside the crucible, and the outer side of the conveying pipe is surrounded by a heat preservation heating structure; the length of the conveying pipe is 1.5-3 times the diameter of the growth furnace.

[0016] Further, the heat preservation heating structure comprises a ceramic tube, a heating layer, a heat preservation layer and a protection cylinder which are arranged outside the conveying pipe from inside to outside, and the inner side of the ceramic tube is attached with a platinum layer.

[0017] The artificial crystal continuous preparation method of the present application adopts the following technical scheme:

[0018] An artificial crystal continuous preparation method comprises: pre-sintering after mixing and grinding the raw materials, then feeding the material into a melting furnace and a growth furnace, keeping the liquid levels of the two consistent through a horizontally extending conveying pipe, growing the crystal by the pulling method, and keeping the temperature in the conveying pipe consistent with the temperature in the growth furnace; after the liquid level in the growth furnace changes, sampling the liquid level height of the growth furnace, controlling the feeding amount in the melting furnace, and keeping the liquid level in the growth furnace in dynamic balance within a set range.

[0019] Further, the dynamic change range of the liquid level in the growth furnace is 1-2mm.

[0020] The beneficial effects of the present application are as follows: compared with the prior art, the artificial crystal continuous feeding device of the present application separates the raw material melting from the crystal growth, realizes the continuous feeding of the molten material in the growth furnace by setting the melting furnace and the conveying pipe, improves the stability of the temperature field in the pulling growth furnace, effectively maintains the stability of the molten liquid in the pulling growth furnace, and realizes the purpose of industrialized continuous growth of high-quality large-size crystals.

[0021] Meanwhile, the conveying pipe in communication with the bottom of the growth furnace and the melting furnace is arranged, the liquid level in the inner cavity of the growth furnace and the melting furnace is consistent, a buffer space for the molten liquid from the melting furnace to the growth furnace is provided, the influence of the high temperature of the molten liquid in the melting furnace on the temperature of the growth furnace is avoided, and the stability of the crystal growth interface melt is improved. The communicator structure is arranged, and the mixed liquid enters the growth furnace along the tangential direction, so that the disturbance of the melt feeding to the crystal growth interface in the growth furnace is effectively reduced. The rotational flow field reduces the temperature gradient of the molten liquid and improves the stability of the crystal growth environment. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced as follows:

[0023] Figure 1 is a specific embodiment structure diagram of the artificial crystal continuous feeding device of the present application;

[0024] Figure 2 is Figure 1 A partial enlarged view of the A part in the figure;

[0025] Figure 3 is Figure 1 the connection cross section view of the conveying pipe and the growth furnace in the figure.

[0026] Marked: 1-feeding bin; 2-metering device; 3-melting furnace; 4-conveying pipe; 5-growth furnace; 6-cooling water channel; 7-feeding pipe; 71-vertical section; 72-inclined section; 8-gas lance; 9-inert gas tank; 10-heat shield; 11-exhaust pipe; 12-crucible one; 13-housing; 14-thermal insulation layer; 15-heating layer; 16-crucible two; 17-ceramic tube; 18-zirconium sand; 19-pulling rod; 20-seed crystal; 21-crystal; 22-laser range finder; 23-sapphire window; 24-controller; 25-on-off valve. DETAILED DESCRIPTION

[0027] In order to make the technical purposes, technical solutions and beneficial effects of the present application more clear, the technical solutions of the present application will be further described in combination with the drawings and specific embodiments.

[0028] The specific embodiments of the artificial crystal continuous feeding device of the present application are as follows:Figures 1 to 3 As shown, the continuous feeding device includes a melting furnace 3 and a growth furnace 5 connected to form a communicating vessel structure through a horizontally extending delivery pipe 4, the melting furnace 3 is provided with a feeding part at the top with an on-off valve 25, the growth furnace 5 is configured with a liquid level measuring structure and a rotating pulling rod 19, the delivery pipe 4 is arranged tangentially along the outermost profile of the inner cavity of the growth furnace 5, and the controller 24 controls the opening and closing of the on-off valve 25 according to the liquid level data.

[0029] Specifically, the cross section of the growth furnace 5 is circular, the inner cavity of the melting furnace 3 is arranged in the same plane with the bottom of the inner cavity of the growth furnace 5, the extension direction of the delivery pipe 4 is arranged tangentially to the outermost profile of the inner cavity of the growth furnace 5 so that the mixed liquid enters the growth furnace 5 along the tangent, and the controller 24 controls the opening and closing of the on-off valve 25 to keep the liquid level in the growth furnace 5 in dynamic balance after the liquid level in the growth furnace 5 drops and rises to a set threshold.

[0030] Among them, the melting furnace 3 and the growth furnace 5 are connected through the bottom communicating delivery pipe 4 to form a communicating vessel structure, which automatically balances the liquid level height on both sides by using the principle of hydrostatics, and the delivery pipe 4 can be designed as an equal-diameter pipeline connection. The outlet direction of the delivery pipe 4 forms a tangent angle with the circular inner wall of the growth furnace 5, so that the inflowing molten liquid moves along the circumference of the furnace wall. By using the controller 24, the measuring structure, and the on-off valve 25, and combining the principle of communicating vessels, the liquid level height in the growth furnace 5 is controlled in real time, and when the liquid level deviates from the set range, the feeding operation is automatically triggered.

[0031] When the melting furnace 3 receives raw materials, the raw materials are heated and melted into molten liquid in the melting furnace 3, which is continuously supplied to the growth furnace 5 through the horizontal delivery pipe 4, and the two naturally form an equal liquid level. When the pulling rod 19 lifts the crystal 21, causing the liquid level in the growth furnace 5 to drop, the controller 24 starts the on-off valve 25 to supplement the material, and the tangential arrangement of the delivery pipe 4 makes the newly inflowing molten liquid rotate along the furnace wall, reducing the direct impact on the growth interface of the crystal 21. The liquid level measuring structure monitors the liquid level height in real time, and triggers the closed-loop control when the change exceeds the threshold. By using the double-furnace communicating structure, the capacity limitation of the raw materials is broken, the closed-loop control system is used to realize automatic and accurate feeding, the tangential arrangement creates a rotating flow field, and the distribution uniformity of the molten liquid is improved, avoiding interference with the growth interface of the crystal.

[0032] In some embodiments, the rotation direction of the pulling rod 19 is the same as the flow direction of the mixed liquid after entering the growth furnace 5. Specifically, the top of the growth furnace 5 is suspended with a pulling device, which includes a rotatable pulling rod 19, the bottom of the pulling rod 19 is fixed with a seed crystal 20, and the bottom of the pulling rod 19 is suspended downward at the liquid level position of the growth furnace 5 to realize crystal growth by conventional pulling method. In this embodiment, the rotation direction of the pulling rod 19 is the rotation direction of the pulling rod 19 in the growth furnace 5, which is configured to be consistent with the flow direction of the liquid in the growth furnace 5, and the flow direction of the mixed liquid after entering the growth furnace 5 is controlled by the tangential arrangement of the conveying pipe 4 described above. By aligning the rotation direction of the pulling rod 19 with the flow direction of the molten liquid, the disturbance of the liquid flow to the growth interface can be reduced, and the turbulence or local temperature fluctuation caused by the difference in direction can be avoided.

[0033] When the molten liquid enters the growth furnace 5, the liquid forms a cyclone in the furnace, and at this time the rotation direction of the pulling rod 19 is synchronized with the liquid cyclone direction, such as the liquid flowing clockwise, the pulling rod 19 is also set to rotate clockwise, and the synchronization of the two makes the liquid flow around the solid-liquid interface stable during crystal growth, avoids the conflict of directions to cause defects or impurities to gather on the crystal surface, and maintains the dynamic balance of the crystal growth interface. In the conventional pulling method, the rotation of the pulling rod 19 is independent of the flow direction of the liquid, which causes the crystal growth interface to be disturbed by the shear force of the liquid flow, and is prone to produce lattice distortion or growth stripes. The synchronous setting can reduce the defects on the crystal surface, improve the uniformity and integrity of the crystal structure, and reduce the risk of crystal growth interruption caused by interface fluctuation.

[0034] In some embodiments, in order to meet the stable feeding, the feeding part includes a feeding pipe 7 arranged at the top of the melting furnace 3, and the outer wall of the feeding pipe 7 is spirally provided with a cooling water channel 6. The cooling water channel 6 is mainly used for cooling the feeding pipe 7 and the material in the feeding pipe 7, so as to avoid the material from adhering to the pipe wall of the feeding pipe 7 or even blocking the pipe due to high temperature.

[0035] Specifically, the cooling water channel 6 is a spiral liquid circulation channel formed around the outer periphery of the tank body, which takes away the heat of the pipe body by circulating cooling medium. The spiral arrangement of the cooling water channel 6 can increase the heat exchange area and form a continuous cooling area, so as to effectively control the axial temperature distribution of the feeding pipe 7. When the material enters the melting furnace 3 through the feeding pipe 7, the annular cooling zone formed by the cooling water channel 6 can reduce the temperature of the pipe body, so that the surface temperature of the material is always lower than the crystallization critical point during the conveying process. When the internal heat of the high-temperature melting furnace 3 is conducted through the pipe wall, the cooling medium forms a counterflow heat exchange in the spiral water channel, and the temperature gradient of different sections of the pipe body is controlled within a preset range, so as to avoid local crystallization of the raw material on the inner wall of the pipe.

[0036] In some embodiments, the feeding pipe 7 comprises vertical sections 71 at both ends and an inclined section 72 connecting the two vertical sections 71, so as to form a Z-shaped pipe structure. The feeding pipe 7 is designed in a Z-shaped structure, which changes the flow direction through the guidance of the inclined section 72, prolongs the material flow path and increases the flow resistance, reduces the flow rate of the material when entering the melting furnace 3, avoids the violent fluctuation of the melting furnace 3 caused by the impact of the material, and prevents the molten liquid in the melting furnace 3 from splashing. At the same time, the arrangement of the inclined section 72 can also buffer the upward hot air flow caused by the air pressure difference between the top and bottom of the feeding pipe 7, which is easy to cause the heating of the feeding pipe 7, and then cause the partial melting and adhesion of the material to the pipe wall or cause the blockage.

[0037] Through two changes of direction and path extension, the kinetic energy of the material is converted into heat energy generated by friction with the pipe wall, thereby reducing the impact of the material on the liquid surface of the melting furnace 3 and maintaining the stability of the liquid surface. The cooperation of the Z-shaped pipe structure and the spiral cooling water channel 6 can further control the temperature of the material, prevent the material from melting or caking too early during the feeding process, and ensure the reliability of the continuous feeding process.

[0038] In some embodiments, a gas lance 8 is arranged on the side wall of the feeding pipe 7 to introduce inert gas into the feeding pipe 7. The nozzle of the gas lance 8 is located above the inclined section 72 and the jet direction extends obliquely downward toward the upper side wall of the inclined section 72. The upper side wall of the inclined section 72 is provided with the gas lance 8 of the inert gas, the gas inlet end of the gas lance 8 is communicated with an inert gas tank 9 for injecting inert gas into the feeding pipe 7 to isolate oxygen, and the jet path of the gas lance 8 covers the internal space of the inclined section 72. The inclined form of the jet direction makes the inert gas flow downward along the pipe wall to form a gas curtain, which can form a covering layer on the inner wall of the feeding pipe 7, effectively isolating the contact between the external air and the material. The inert gas can fully fill the pipe cavity space to prevent the material from adhering or oxidizing on the inner wall of the inclined section 72, and the pressure gradient generated by the gas flow can assist the material to move downward along the pipe wall, reducing the risk of blockage. It can not only avoid the adhesion of the material to the wall caused by high temperature, but also offset the upward air flow caused by the air pressure difference between the top and bottom of the feeding pipe 7, thereby avoiding the high temperature of the feeding pipe 7 and the adhesion of the material to the wall caused by the air flow.

[0039] In some embodiments, the liquid level measuring structure comprises a laser range finder 22 arranged on the top wall of the growth furnace 5, and the laser emission path of the laser range finder 22 is perpendicular to the liquid surface of the growth furnace 5. The structure and principle of the laser range finder 22 are basically the same as those of the prior art, and will not be described in detail. Specifically, a pulse or phase laser ranging module can be used to realize it, which is installed at the shoulder position of the growth furnace 5. The vertically arranged laser emission path is coincident with the normal direction of the laser beam and the liquid surface, which can avoid the measurement error caused by the fluctuation of the liquid surface.

[0040] Specifically, a sapphire window 23 is arranged at the shoulder position of the growth furnace 5, and an optical range finder is fixed above the sapphire window 23. The laser is emitted into the growth furnace 5 in the vertical direction, and is used to monitor the height change of the molten material in the growth furnace 5. It should be noted that the laser range finder 22 is configured with a filtering device, and the near-infrared to mid-infrared waveband laser is used because the light in these wavebands can better penetrate the high-temperature gas environment in many cases and is not easily absorbed or scattered. The optional near-infrared wavelengths include 905 nanometers, 1064 nanometers, 1310 nanometers, and 1550 nanometers, etc., wherein the 1550 nanometer wavelength has higher eye safety.

[0041] The laser range finder 22 continuously emits a laser beam to the liquid surface during the crystal growth process, and obtains real-time liquid surface height data by calculating the time difference between emission and reception. When the liquid surface changes in height due to crystal 21 pulling or raw material replenishment, the range finder feeds back data to the controller 24, and the controller 24 controls the on-off valve 25 of the feeding pipe 7 of the melting furnace 3 to open and close according to the preset threshold. Since the laser beam propagates perpendicular to the liquid surface, the influence of liquid surface ripples on measurement accuracy can be effectively eliminated, and the top installation method avoids the interference problem of the furnace body structure that may exist in the lateral installation. Non-contact laser measurement not only avoids direct contact between the sensor and the high-temperature liquid, but also realizes continuous monitoring with millimeter-level precision, significantly improving the response speed and reliability of the liquid level control. The influence of high temperature and liquid flow on detection accuracy is effectively overcome, providing a high-precision feedback signal for continuous feeding control, thereby ensuring the stability of the crystal growth interface and improving the crystallization quality and growth efficiency of the single crystal.

[0042] In some embodiments, the melting furnace 3 and the growth furnace 5 each include a crucible and a material heating structure arranged outside the crucible, and the outer side of the conveying pipe 4 is surrounded by a heat preservation heating structure; the length of the conveying pipe 4 is 1.5-3 times the diameter of the growth furnace 5.

[0043] The crucible in the melting furnace 3 is crucible one 12, and the crucible in the growth furnace 5 is crucible two 16. The material heating structure is arranged outside the crucible, and can use an induction coil or a resistance heating wire to maintain the temperature consistency of the molten material through uniform heating.

[0044] Specifically, as shown in FIG. 1, the conveying pipe 4 is arranged in the melting furnace 3 and the growth furnace 5, and the conveying pipe 4 is connected to the feeding pipe 7 of the melting furnace 3 and the feeding pipe 8 of the growth furnace 5. The conveying pipe 4 is connected to the feeding pipe 7 of the melting furnace 3 and the feeding pipe 8 of the growth furnace 5. Figure 1As shown, the melting furnace 3 includes a crucible 12, the top of which is provided with a heat shield 10, and the top of the melting furnace 3 is provided with an exhaust duct 11. The outer side of the crucible 12 is provided with a heating layer 15, a heat preservation layer 14, and a shell 13 from the inside to the outside. The growth furnace 5 includes a crucible 16, the top of which is provided with a pulling device, and the outer side of the crucible 16 is provided with a heating layer 15, a heat preservation layer 14, and a shell 13 from the inside to the outside. Zirconium sand 18 is filled between the heating layer 15 and the crucible 16, and the filling height of the zirconium sand 18 is 1 / 2-2 / 3 of the height of the crucible 16, which plays a heat preservation role.

[0045] The crucibles of the melting furnace 3 and the growth furnace 5 are independently temperature-controlled through the material heating structure, which ensures that the molten material maintains uniform temperature distribution before being transported. The heat preservation and heating structure on the outer side of the transport pipe 4 avoids solidification or composition segregation of the molten material due to temperature drop during transportation through multi-layer heat insulation and auxiliary heating. The ratio of the length of the transport pipe 4 to the diameter of the growth furnace 5 is designed to ensure that the molten material is fully mixed before entering the growth furnace 5, while avoiding increased flow resistance caused by excessive pipe length. The whole process temperature control of the molten material from the melting furnace 3 to the growth furnace 5 balances the flow efficiency and mixing effect through the optimization of the length ratio of the transport pipe 4.

[0046] In some embodiments, the heat preservation and heating structure includes a ceramic tube 17, a heating layer 15, a heat preservation layer 14, and a protective cylinder, which are sequentially arranged on the outer side of the transport pipe 4 from the inside to the outside. The inner side of the ceramic tube 17 is attached with a platinum layer. The platinum layer is a metal layer attached to the inner surface of the ceramic tube 17, which can be formed by electroplating or spraying process, and is used to prevent corrosion caused by direct contact between the molten liquid and the ceramic tube 17. The heating layer 15 is used to maintain the temperature of the material in the transport pipe 4. The transport pipe 4 as a whole can provide a temperature buffer area for the crucible 12 and the crucible 16. Since the setting temperature of the crucible 12 is higher than that of the crucible 16, the temperature of the molten material can be reduced to the same as that in the crucible 16 through the transport pipe 4, thereby avoiding changes in the temperature field in the crucible 16 and causing the crystal quality to decrease.

[0047] Through the combination of the ceramic tube 17 and the platinum layer, both high-temperature resistance and the prevention of impurities interfering with the molten liquid are achieved, and through the layered heating and heat insulation design, the temperature of the transport pipe 4 is uniform and stable. The flowability of the material in the transport pipe 4 is effectively maintained, the crystal growth defects caused by temperature fluctuations are avoided, the energy consumption is reduced, and the service life of the device is prolonged.

[0048] In some embodiments, the top of the melting furnace 3 is provided with a feeding bin 1, as shown in FIG. 1. Figure 1As shown, it is located above the melting furnace 3, and the powder mixture is in the feeding bin 1. The feeding bin 1 is connected with the metering device 2 at the discharge end, which is used for accurate metering of the material in the feeding bin 1. The discharge end of the metering device 2 is connected to the above-mentioned feeding pipe 7. The on-off valve 25 is arranged on the feeding pipe 7. The mixed powder is supplied into the melting furnace 3 through the feeding bin 1, and the feeding amount of the material is controlled through the on-off valve 25.

[0049] The embodiment of the continuous preparation method of artificial crystals according to the present application comprises pre-sintering after raw material mixing and grinding, and then feeding the material into the melting furnace 3 and the growth furnace 5. The liquid levels of the two are kept consistent through the horizontally extending conveying pipe 4. The crystal growth is carried out by the pulling method. The temperature in the conveying pipe 4 is consistent with the temperature in the growth furnace 5. After the liquid level of the growth furnace 5 changes, the liquid level height of the growth furnace 5 is sampled, and the feeding amount in the melting furnace 3 is controlled, so that the liquid level in the growth furnace 5 is in dynamic balance within the set range.

[0050] Specifically, the pre-sintering after raw material mixing and grinding is to uniformly mix different raw material powders, and then pre-grind and high-temperature treatment, which can reduce the time consumption in the melting stage. After pre-sintering, the material is added into the melting furnace 3 and the growth furnace 5 respectively. The melt in the melting furnace 3 flows into the growth furnace 5 through the horizontal conveying pipe 4, forming a stable communication liquid level. When the pulling rod 19 rotates to drive the crystal 21 to grow, the liquid level gradually decreases due to the pulling of the crystal. At this time, the liquid level measurement structure monitors the data in real time. When the liquid level is lower than the threshold value, the controller 24 opens the feeding of the melting furnace 3, and the supplemented melt flows into the growth furnace 5 through the conveying pipe 4, so that the liquid level returns to the set range. Conversely, when the liquid level is too high, the feeding is stopped, thereby realizing the dynamic balance of the liquid level. In some specific embodiments, the feeding operation of the melting furnace 3 can be realized by segmented feeding, for example, the feeding amount is 0.5%-1% of the volume of the growth furnace 5 each time, so as to avoid excessive feeding leading to violent fluctuation of the liquid level. Through the communication structure of the melting furnace 3 and the growth furnace 5, continuous feeding is realized, and combined with the dynamic control of the liquid level, the uniformity of the melt composition can be maintained, and the crystal defects can be avoided. Through the dynamic liquid level control, the stability of the melt amount in the crystal growth process is ensured, thereby improving the crystal yield and growth efficiency.

[0051] In some embodiments, the liquid level in the growth furnace 5 dynamically changes by 1-2 mm. This parameter is set as a key indicator for maintaining the stability of the solid-liquid interface during crystal growth. Excessive fluctuations can lead to stress concentration in the crystal, while too small a control range can increase the frequency of equipment regulation. When the liquid level decreases due to the consumption of raw materials, the liquid level measurement structure detects that the liquid level deviates from the reference value in real time. The controller 24 sends an instruction to open the on-off valve 25 of the feeding part of the melting furnace 3 to supplement the raw materials according to the preset 1-2 mm allowable fluctuation range. When the supplemented molten material enters the growth furnace 5 through the horizontal conveying pipe 4, due to the tangential arrangement of the conveying pipe 4, the rotational flow generated by the material inflow is consistent with the rotation direction of the pulling rod 19, effectively reducing the disturbance of the liquid level. When the liquid level rises to the upper limit of the allowable range, the controller 24 immediately closes the feeding valve, thereby forming a periodic and small amount of feeding mechanism. This avoids the sudden drop in melt temperature and component segregation caused by large-scale feeding. It also takes into account the response speed of the equipment actuator, so that the feeding operation frequency and the crystal growth rate reach a dynamic balance.

[0052] Taking lithium niobate crystal as an example, the continuous preparation process mainly includes the following steps:

[0053] (1) Mixing, putting the raw materials lithium carbonate and niobium pentoxide into a mixing device, preferably a planetary ball mill or a jar mill, and adding a dispersant for mixing; the grinding body of the mixing device is zirconia ball; preferably, the mass ratio of the raw materials to the grinding body is 1:2-1:5, the mass grading of the zirconia balls in the grinding body is 10mm ball:5mm ball:1mm ball:0.3mm ball=1:1:5:3, the grinding time is 1-5 hours; the dispersant is one or a combination of ethanol, ethylene glycol, polyethylene glycol, glycerol, and triethanolamine, and the dosage is 0.5%-2% of the mass of the raw materials;

[0054] (2) Pre-sintering, placing the mixed raw materials into a box furnace for pre-sintering, the pre-sintering temperature is 900-1000℃, the heating rate is 300-400℃ / h, the temperature is kept at 500-600℃ for 3-4h, the pre-sintering time is 6-8h, and the powdery lithium niobate polycrystal material is obtained, and the lithium niobate polycrystal material is placed into the feeding bin 1;

[0055] (3) melting, the lithium niobate polycrystalline material is added into the crucible one 12 in the melting furnace 3 and the crucible two 16 in the pulling growth furnace 5 respectively, the pulling growth furnace 5, the melting furnace 3 and the cooling water circulating device are opened through the controller 24, high temperature melting is carried out, the Li: Nb molar ratio of the lithium niobate polycrystalline material in the crucible one 12 is 1:1, the Li: Nb molar ratio of the lithium niobate polycrystalline material in the crucible two 16 is 58:42; the lithium niobate polycrystalline material with different Li / Nb ratios is realized by controlling the molar ratio of the raw material in step (1); the temperature of the pulling growth furnace 5 is set to 1280-1320 DEG C, the temperature of the melting furnace 3 is set to be higher than the temperature setting of the pulling growth furnace 5 (the temperature is 20-50 DEG C higher), the conveying pipe 4 is provided with a heating device and is set to the same temperature as the pulling growth furnace 5, the purpose is to keep the stability of the temperature of the molten liquid in the pulling growth furnace 5;

[0056] (4) crystal growth, the crystal is grown through the shoulder, the equal diameter and the tailing process by using the pulling method process in the prior art, the high quality lithium niobate crystal is obtained; in the crystal growth process, the molten liquid is continuously conveyed from the crucible one 12 and the conveying pipe 4 to the crucible two 16, the height of the molten liquid surface in the crucible two 16 is kept unchanged; specifically, the laser range finder 22 detects the height of the molten liquid surface in the pulling growth furnace 5, when the height difference between the detected liquid surface and the initial liquid surface is more than 1-2 mm, the on-off valve 25 at the bottom of the melting furnace 3 is opened to supplement the material to the initial height, so that the height of the liquid surface is kept unchanged. Through the structure formed by the communicating vessels, the Li / Nb stability of the molten liquid in the pulling growth furnace 5 is effectively kept, the temperature field stability and the crystal quality affected by the fluctuation of the liquid surface height are avoided, and the quality of the lithium niobate crystal is improved.

[0057] Finally, it should be explained that: the above examples are only used for illustration but not for limiting the technical solutions of the present application, any equivalent replacement and modification or partial replacement of the present application without departing from the spirit and scope of the present application should be covered in the protection scope of the claims of the present application.

Claims

1. An intraocular lens continuous feeding device, characterized in that: It includes a melting furnace and a growth furnace, a conveying pipe connecting the melting furnace and the growth furnace, and a controller, wherein: A feeding part is provided on the top of the melting furnace, and an on-off valve is provided in the feeding part; The growth furnace has a liquid level measurement structure, a rotating lifting rod is provided on the top of the growth furnace, and the cross section of the inner cavity of the growth furnace is circular; The inner cavity of the melting furnace and the bottom of the inner cavity of the growth furnace are arranged in the same plane, and the delivery pipe extends horizontally to the bottom of the side wall of the melting furnace and the growth furnace to form a communicating vessel structure with equal liquid levels inside the two, and The extending direction of the delivery pipe is tangential to the outermost contour of the inner cavity of the growth furnace so that the mixed liquid enters the growth furnace along the tangential direction; The controller is connected to the liquid level measurement structure for sampling and is connected to the on-off valve for controlling the on-off valve to control the opening and closing of the on-off valve to keep the liquid level in the growth furnace in dynamic balance after the liquid level in the growth furnace drops and rises to a set threshold.

2. The intraocular lens continuous feeding device according to claim 1, characterized in that: The rotation direction of the lifting rod is the same as the flow direction of the mixed liquid after entering the growth furnace.

3. The intraocular lens continuous feeding device according to claim 1, characterized in that: The feeding part comprises a feeding pipe arranged on the top of the melting furnace, and a cooling water channel is spirally arranged on the outer wall of the feeding pipe.

4. The intraocular lens continuous feeding device according to claim 4, characterized in that: The feed pipe includes vertical sections at both ends and an inclined section connecting the two vertical sections, so that the feed pipe forms a Z-shaped pipe structure.

5. The intraocular lens continuous feeding device according to claim 5, characterized in that: A gas spray gun is arranged on the side wall of the feed pipe to introduce inert gas into the feed pipe. The nozzle of the gas spray gun is located above the inclined section, and the spray direction extends obliquely downward toward the upper side wall of the inclined section.

6. The intraocular lens continuous feeding device according to claim 1, characterized in that: The liquid level measurement structure includes a laser rangefinder arranged on the top wall of the growth furnace, and the laser emission path of the laser rangefinder is perpendicular to the liquid level of the growth furnace.

7. The intraocular lens continuous feeding device according to claim 1, characterized in that: The melting furnace and the growth furnace both include a crucible and a material heating structure arranged around the outside of the crucible. The outside of the delivery pipe is surrounded by a heat preservation and heating structure. The length of the delivery pipe is 1.5-3 times the diameter of the growth furnace.

8. The intraocular lens continuous feeding device according to claim 7, characterized in that: The heat preservation and heating structure includes a ceramic tube, a heating layer, a heat preservation layer, and a protective tube which are arranged on the outside of the conveying pipe from the inside to the outside, wherein a platinum layer is attached to the inner side of the ceramic tube.

9. A method for continuously preparing intraocular lenses using the intraocular lens continuous feeding device according to any one of claims 1 to 8, characterized in that: include: The raw materials are mixed, ground, and pre-sintered. The materials are then fed into a melting furnace and a growth furnace. The liquid levels of the two furnaces are kept consistent through a horizontally extending conveying pipe. Crystal growth is performed by the Czochralski method. The temperature in the conveying pipe is consistent with the temperature of the growth furnace. After the liquid level in the growth furnace changes, the liquid level height of the growth furnace is sampled and the feed amount in the melting furnace is controlled to keep the liquid level in the growth furnace in dynamic balance within a set range.

10. The method for continuous preparation of intraocular lenses according to claim 9, characterized in that: The dynamic change range of the liquid level in the growth furnace is 1-2mm.

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