Evaporation-method oriented growth device and method for long-rod-shaped KDP (potassium dihydrogen phosphate) crystals

Abstract

The invention belongs to the technical field of crystal growth, and particularly relates to an evaporation-method oriented growth device and method for long-rod-shaped KDP (potassium dihydrogen phosphate) crystals. The evaporation crystal growing device internally provided with growth solution is fixedly erected in the water bath heating and heat preservation device, the solvent evaporation pond is installed on the seed crystal fixing base through the crystal growing groove, a fluid channel communicated with the seed crystal fixing base and the solvent evaporation pond is reserved in the crystal growing groove, and the fluid channel is a long-rod-shaped cavity. The heating and heat preservation ends of the two temperature control subsystems are located on the outer side of the evaporation crystal development device and are different in installation height. The invention provides a new thought for obtaining the long-rod-shaped oriented KDP crystal, a self-designed evaporation crystal development device is adopted, oriented growth of the crystal is carried out based on a solvent evaporation method, the utilization rate of raw materials is high, the growth speed is high, the stability of a solution can be effectively improved, and the possibility of growth failure can be reduced; meanwhile, mechanical cutting can be avoided, and the damage probability of the crystal is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of crystal growth, and in particular relates to an evaporation method directional growth device and method for long rod-shaped KDP crystals. Background Art

[0002] Potassium dihydrogen phosphate (chemical formula KH 2 PO 4 KDP (Korean Derivatives Processing Technology, KDP for short) crystal is a nonlinear optical material with excellent performance. It has the advantages of large nonlinear optical coefficient, wide transmission band, high resistance to laser-induced damage, easy growth of large-diameter single crystals, etc., and is widely used in the laser field. KDP crystal is the only nonlinear optical crystal that can be used for inertial confinement fusion (ICF) engineering so far. The main growth method is the point seed crystal rapid growth method. The point seed crystal rapid growth method is to place the point seed crystal in a solution prepared with growth raw materials, and make it in a supersaturated state by cooling. The raw materials dissolved in the solution gradually crystallize and precipitate on the surface of the point seed crystal, so that it continues to grow and obtain larger crystals. Due to the room temperature and the properties of the material itself, the cooling range is usually selected to be 55℃ to 25℃, but because the raw materials still have a high solubility at room temperature, the solute utilization rate of this process is only 32.9%. At the same time, due to the certain distortion of the lattice near the interface between the conical surface and the cylindrical surface of the crystal, the performance of the light beam passing through is affected, resulting in a decrease in the utilization rate of the crystal. In order to avoid the interface between the conical surface and the cylindrical surface of the crystal, it is usually necessary to use a rod-shaped seed crystal in the Z direction and place it between two parallel plates, so that the crystal can only expand and extend in the cylindrical direction to avoid the appearance of the interface. The traditional method of obtaining rod-shaped KDP single crystals is to use mechanical cutting to obtain large-sized block KDP crystals grown by the cooling method. However, mechanical equipment such as wire cutting machines can easily cause irreversible damage to the crystals due to heat accumulation during post-processing, which seriously affects the success rate of obtaining rod-shaped KDP single crystals. At the same time, the block KDP crystals grown by the cooling method have very low raw material utilization, have great disadvantages in the volume and floor space of the growth container, and are expensive.

[0003] Therefore, designing a set of evaporation-based directional growth equipment for long rod-shaped KDP crystals that avoids mechanical post-processing can solve the problem of seed source in large-sized KDP crystals, thereby greatly improving the quality of large-sized KDP crystals and having considerable industrial production value and economic benefits. Summary of the invention

[0004] In order to solve the problems existing in the prior art, the present invention provides an evaporation-based directional growth device and method for long rod-shaped KDP crystals, which adopts a self-designed evaporation crystal growing device to carry out directional growth of crystals. It can obtain long rod-shaped KDP crystals along a specific direction at a faster speed with a raw material utilization rate several times that of the traditional cooling growth method, completely avoids subsequent mechanical processing, and greatly reduces the floor space occupied by the crystal growing device.

[0005] The technical solution adopted by the present invention to solve its technical problems is as follows: an evaporation method directional growth device for long rod-shaped KDP-type crystals, comprising: an evaporation crystal growing device and a water bath heating and insulation device, the evaporation crystal growing device with a built-in growth solution is fixed and stands in the water bath heating and insulation device; the bottom of the evaporation crystal growing device is a crystal seed fixing seat, and the upper end is provided with a solvent evaporation pool, the solvent evaporation pool is installed on the crystal seed fixing seat through a crystal growth groove, and a fluid channel connecting the crystal seed fixing seat and the solvent evaporation pool is left in the crystal growth groove, and the fluid channel is a long rod-shaped cavity; the water bath heating and insulation device comprises: two sets of temperature control subsystems, the heating and insulation ends of the temperature control subsystems are located on the outside of the evaporation crystal growing device and are installed at different heights.

[0006] Preferably, the heating and heat preservation end of one temperature control subsystem is placed outside the solvent evaporation pool, and the heating and heat preservation end of the other temperature control subsystem is placed outside the crystal growth tank.

[0007] Preferably, the solvent evaporation pool is funnel-shaped.

[0008] Preferably, the upper end of the solvent evaporation pool is open and is equipped with an evaporation rate control cover, and the upper end of the solvent evaporation pool is also covered with a microporous semipermeable membrane, and the evaporation rate control cover is located above the microporous semipermeable membrane.

[0009] Preferably, the solvent evaporation pool has an inclination angle of 20°-30°; and the micropore diameter of the microporous semipermeable membrane is less than 100 nanometers.

[0010] Preferably, the temperature control subsystem comprises: a ring heater and a matching thermocouple, wherein one ring heater is installed via a fixed bracket standing in the water bath heating and heat preservation device, and the ring heater moves up and down along the crystal growth trough.

[0011] Preferably, it further comprises: a crystal growing device coupling bracket, the evaporation crystal growing devices are arranged in parallel on the crystal growing device coupling bracket, and the crystal growing device coupling bracket is fixed in the water bath heating and heat preservation device.

[0012] Preferably, in the crystal growth tank, a stainless steel shell is fixedly mounted on the organic glass cover plate, and a U-shaped groove is disposed between the organic glass cover plate and the stainless steel shell.

[0013] A method for directional growth of long rod-shaped KDP crystals by evaporation method, the steps are as follows: S1, in the preparation stage, firstly, the seed crystal is placed in the seed fixing groove at the bottom of the evaporation crystal growing device, and then the assembled and sealed evaporation crystal growing device is fixed in the water bath heating and heat preservation device, and the water bath heating and heat preservation device is started for preheating; S2, in the growth stage, the growth solution is injected into the solvent evaporation tank, and the heating and insulation temperatures of the two temperature control subsystems are respectively set. The heating and insulation temperature of the temperature control subsystem located outside the crystal growth tank is 1-2°C higher than the temperature corresponding to the saturated solution of the crystal material, and the heating and insulation temperature of the other temperature control subsystem is higher than the heating and insulation temperature of the temperature control subsystem located outside the crystal growth tank by more than 6°C, and the opening of the evaporation rate control cover is adjusted so that the replenishment and consumption rates of the supersaturation of the growth solution are consistent; S3, completion stage, after the crystal grows to the expected size, set the two temperature control subsystems to slowly cool down to the ambient temperature, and take out the long rod-shaped KDP crystal grown along a specific direction.

[0014] Preferably, during the growth stage, the method further comprises: adjusting the height of a heater of a temperature control subsystem located outside the crystal growth tank according to the height of the crystal so that the heater is located 10-15 cm above the crystal.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. The directional growth device in the present application is provided with a restrictive crystal growth groove, which provides external conditions conducive to the one-dimensional growth of the crystal, avoids the subsequent mechanical processing, and greatly reduces the area occupied by the crystal grower; 2. The directional growth device in this application is equipped with a dual temperature control system to facilitate system temperature control, so that the solution is in a smooth steady-state transition, promoting the directional and stable growth of crystals; 3. Adopting an annular heater, the height and temperature are adjusted along the crystal growth groove according to the crystal growth height, which improves the quality of the long rod-shaped oriented KDP crystal; 4. A microporous semipermeable membrane and an evaporation rate control cover are provided on the solvent evaporation pool to increase the stability of the solution; 5. The use of solvent evaporation-based directional growth can increase the raw material utilization rate to nearly 100%; In summary, the present application provides a new idea for obtaining long rod-shaped oriented KDP crystals. It adopts a self-designed evaporation crystal growing device and carries out oriented growth of crystals based on the solvent evaporation method, which can achieve stable, controllable and efficient growth of long rod-shaped KDP crystals, high raw material utilization rate, fast growth rate, and can effectively increase the stability of the solution and reduce the possibility of growth failure; at the same time, mechanical cutting can be avoided and the chance of crystal damage is reduced; the structure is simple, the equipment size is small, and the production cost is low; the equipment as a whole is in static conditions, with high stability and easy operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the directional growth device of the long rod-shaped KDP-type crystal by evaporation method in the present invention.

[0017] Figure 2 It is a schematic diagram of the cross section of the crystal growth trough.

[0018] Figure 3 It is a top view of the evaporation rate control cover.

[0019] Figure 4 It is a schematic diagram of the installation and use of the crystal growing device coupling bracket of the present invention.

[0020] Figure 5 This is a graph showing the crystal transmittance test results of samples prepared by the equipment of this application and traditional sample preparation.

[0021] Figure 6 This is a graph showing the test results of the second harmonic conversion efficiency of samples prepared by the equipment of this application and traditional samples.

[0022] Figure 7 This is a graph showing the test results of laser induced damage threshold for samples prepared by the equipment in this application and traditional samples.

[0023] Figure 8 This is a comparison chart of the raw material utilization rate between the method in this application and the traditional method.

[0024] In the figure: 1. evaporation rate control cover, 2. solvent evaporation pool, 3. crystal growth tank, 4. seed crystal fixing seat, 5. growth solution, 6. microporous semipermeable membrane, 7. evaporation crystal growing device, 8. organic glass cover, 9. stainless steel shell, 10. U-shaped groove, 11. row bracket, 12. water bath liquid, 13. seed crystal, 14. high temperature insulation device, 15. low temperature insulation device, 16. high temperature heating equipment, 17. low temperature heating equipment, 18. high temperature probe, 19. low temperature probe, 20. control system, 21. fixed bracket.

[0025] Figure 5-7 Among them, new samples 1, 2, and 3 are samples prepared by the equipment of this application; traditional samples 1, 2, and 3 are samples prepared by traditional equipment. Figure 8In the present invention, the novel method is the method in this application. DETAILED DESCRIPTION

[0026] In order to facilitate the understanding of the present invention, the present invention is described in more detail below in conjunction with the accompanying drawings and specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described in this specification. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0027] Example 1: Combination Figure 1 It is understood that an evaporation method directional growth device for long rod-shaped KDP crystals includes: an evaporation crystal-growing device 7 and a water bath heating and heat preservation device. The evaporation crystal-growing device 7 with a built-in growth solution is fixed in the water bath heating and heat preservation device. The evaporation crystal-growing device 7 consists of three parts: a funnel-shaped solvent evaporation pool 2 at the top, a detachable long rod-shaped crystal growth groove 3 in the middle, and a seed holder 4 at the bottom. The three parts are connected and sealed by silicone rubber sealant in the vertical direction. A fluid channel is left in the crystal growth groove 3, and the fluid channel connects the seed holder 4 with the solvent evaporation pool 2. The main parts of the evaporation crystal-growing device 7 are connected and fixed by silicone rubber sealant to ensure that the internal solution does not leak, while allowing the parts to be disassembled and separated, which is conducive to the acquisition of long rod-shaped crystals. The use of the seed holder 4 at the bottom of the restrictive crystal growth groove 3 can ensure the use of specific tangential seeds and has a certain ability to protect the seeds from deformation. The water bath heating and heat preservation device comprises: two sets of temperature control subsystems, wherein the heating and heat preservation end of one temperature control subsystem is placed outside the solvent evaporation pool 2, and the heating and heat preservation end of the other temperature control subsystem is placed outside the crystal growth tank 3. The water bath heating and heat preservation device controls the solvent evaporation pool 2 and the restricted crystal growth tank 3 respectively through the upper and lower temperature control systems with water as the medium.

[0028] In one embodiment, the solvent evaporation pool 2 has an inclination angle of 20°-30°, which is used to promote the transport of supersaturation generated by solvent evaporation to the crystal surface.

[0029] In one embodiment, the solvent evaporation pool 2 has an upper opening and is provided with a microporous semipermeable membrane 6. The microporous semipermeable membrane 6 has a micropore diameter of less than 100 nanometers, which can ensure that the solvent molecules evaporate and escape while avoiding the disturbance of the external environment to the growth solution, thereby improving the stability of the growth process. The microporous semipermeable membrane 6 is covered with an evaporation rate control cover 1, such as Figure 3As shown, the evaporation rate control cover 1 has a structure for adjusting the opening size, which is used to control the evaporation rate of the solvent. The opening area of ​​the evaporation rate control cover 1 can be adjusted in real time according to the amount of raw materials in the solution consumed by crystal growth, so that the evaporation rate is controllable, the replenishment and consumption rate of supersaturation are reasonably configured, and the growth driving force inside the solution is ensured to be within a relatively stable range, effectively improving the growth rate and quality uniformity of the crystal.

[0030] In one embodiment, the temperature control subsystem includes: a ring heater and a matching thermocouple. There is water as a heat conduction and heat insulation medium on the outside of the evaporation crystal growing device 7. A ring heater and a matching thermocouple are arranged on the outside of the detachable long rod-shaped crystal growth trough 3 to monitor and control the temperature of the water bath.

[0031] In one embodiment, there is another annular heater that can move up and down outside the evaporation crystal incubator 7, and the temperature is controlled by the matching thermocouple, and the set temperature and height are within a certain preset range to ensure the stability of the growth driving force in the crystal growth environment. The temperature preset range is set with reference to the temperature setting corresponding to the saturated solution of the crystal material; the height preset range is 10-16 cm above the actual growth height of the crystal.

[0032] In one embodiment, in combination Figure 4 It is understood that it also includes: a crystal growing device row bracket, the evaporation crystal growing device 7 can be placed in the crystal growing device row bracket in sequence and in parallel at the same horizontal height, and in the same water bath heating and heat preservation device, the temperature is uniformly controlled by the heat transfer medium water, which further optimizes the complexity of the device and reduces the production cost.

[0033] In one embodiment, in combination Figure 2 It is understood that the detachable long rod-shaped crystal growth groove 3 can be disassembled into a plexiglass U-shaped groove 10, which is composed of a plexiglass cover plate 8 and a stainless steel shell 9, wherein the thickness of the plexiglass cover plate 8 is 5 mm, the thickness of the stainless steel shell 9 is 5 mm, and they are fixedly connected by stainless steel screws. The plexiglass U-shaped groove 10 is 1 mm thick and is placed in a cavity composed of the plexiglass cover plate 8 and the stainless steel shell 9 to ensure that the geometric shape of the container does not deform during the growth process of the morphology of the crystal inside it; and it is conducive to the demolding of the plexiglass U-shaped groove 10 and the long rod-shaped crystal inside.

[0034] The crystal directional growth method: The seed crystal with a specific orientation is placed in the seed crystal fixing groove at the bottom of the evaporation crystal growing device 7, fixed in the inner cavity of the organic glass U-shaped groove 10 in the detachable long rod-shaped crystal growth groove 3 through silicone rubber sealant, and then connected to the funnel-shaped solvent evaporation pool 2 through silicone rubber sealant, covered with a microporous semipermeable membrane 6 and an evaporation rate control cover 1, and fixed on the crystal growing device rack 11 and placed in a water bath heating and heat preservation device; A saturated solution of the crystal material is injected into the solvent evaporation pool 2, and the opening size of the evaporation rate control cover 1 is adjusted according to the quality of the raw materials consumed by the actual growth of the crystal. The water bath heating and heat preservation device is turned on, and the two sets of temperature control systems are adjusted according to the initial concentration of the solution. At the same time, the movable ring heater moves to the target height and gradually rises as the height of the crystal increases. Generally, the height of the movable ring heater is located 10-15 cm above the crystal; The solution inside the solvent evaporation pool 2 gradually decreases as it evaporates until it is completely consumed, causing the height of the seed crystals with a specific orientation inside the evaporation crystal incubator 7 to continue to rise, and the growth space of the seed crystals is restricted in a specific direction until they grow into rod-shaped single crystals with a larger aspect ratio. The array-type electric heating temperature control device ensures that the growth driving force gradient near the crystal is stable and controllable. After the growth is completed, the detachable long rod-shaped crystal growth groove 3 is disassembled, and finally the plexiglass U-shaped groove 10 and the rod-shaped crystals therein can be separated.

[0035] Example 2: Combination Figure 1-4 It is understood that an evaporation method directional growth device for long rod-shaped KDP crystals includes: an evaporation rate control cover 1, a funnel-shaped solvent evaporation pool 2, a detachable long rod-shaped crystal growth tank 3, a seed holder 4 and a growth solution 5 therein. The seed holder 4 is connected to the detachable long rod-shaped crystal growth tank 3 and the funnel-shaped solvent evaporation pool 2 through the detachable long rod-shaped crystal growth tank 3. After the opening of the solvent evaporation pool 2 is covered with a microporous semipermeable membrane 6, the evaporation rate control cover 1 is installed to form an evaporation crystal growing device 7. The detachable long rod-shaped crystal growth tank 3 is composed of a plexiglass cover plate 8 and a stainless steel shell 9, and a plexiglass U-shaped groove 10 is fixed on its inner side. The evaporation crystal growing device 7 can be fixed on a crystal growth row bracket 11 and set in a water bath liquid 12.

[0036] Working principle: When using the present invention, first, the organic glass cover plate 8 and the stainless steel shell 9 are connected and fixed by stainless steel screws, the organic glass U-shaped groove 10 is placed in the internal long rod-shaped cavity, the seed crystal 13 for growth is placed on the seed holder 4, and fixed in the internal cavity of the organic glass U-shaped groove 10 by silicone rubber sealant, and the funnel-shaped solvent evaporation pool 2 is connected with silicone rubber sealant on the other side, the microporous semipermeable membrane 6 is covered at the opening of the larger side of the funnel-shaped solvent evaporation pool 2, and the evaporation rate control cover 1 is pressed thereon. The evaporation crystal incubator 7 is fixed in the water bath liquid 12, the high-temperature insulation device 14 is placed at a higher longitudinal position, and the low-temperature insulation device 15 is placed at a lower longitudinal position. The temperature difference formed can obtain supersaturation, and the heating method of the water bath liquid 12 can make the temperature and solute distribution of the growth solution 5 more uniform, and the precipitated solute causes the seed crystal 13 to start growing.

[0037] In the above technical scheme, a temperature control system is also included; the temperature control system is composed of the high-temperature insulation device 14 and the low-temperature insulation device 15 arranged at different positions, and the two insulation devices are specifically composed of a high-temperature heating device 16 and a low-temperature heating device 17, a high-temperature probe 18 and a low-temperature probe 19 and a control system 20; the high-temperature heating device 16 and the low-temperature heating device 17 are specifically heating rods immersed in the water bath liquid 12; the high-temperature probe 18 and the low-temperature probe 19 are temperature sensors immersed in the water bath liquid 12; the low-temperature heating device 17 and the low-temperature probe 19 can be moved in the longitudinal direction with the help of a fixed bracket 21, and the heating rod and the temperature sensor are connected to the control system 20 through wires.

[0038] Working principle: By setting a high-temperature probe 18 located in the water bath liquid 12, the current temperature parameters of the water bath liquid 12 can be stably obtained, providing a reference for the subsequent crystal growth temperature adjustment; the high-temperature heating device 16 can control the temperature in the water bath liquid 12 and provide stable heat for the evaporation of the solvent, while the low-temperature probe 19 can detect the temperature parameters near the growth surface of the seed crystal 13 in real time. By moving the low-temperature heating device 17, the temperature distribution of the growth solution 5 along the longitudinal direction can be adjusted to achieve precise temperature control, and then the supersaturation gradient of the solution between the seed crystal 13 and the funnel-shaped solvent evaporation pool 2 can be adjusted in time to improve the growth quality of the seed crystal 13.

[0039] In the above technical solution, a method for growing a long rod-shaped single crystal material along a specific direction based on a solvent evaporation method comprises the following specific processes: Step 1: KH 2 PO 4The powder raw material (analytical grade) and the solvent high-purity deionized water (resistivity>17.5MΩ / cm) were prepared into a growth solution 5 with a mass fraction of 23.7%. The growth solution 5 was filtered using a commercially available 0.1μm and 0.05μm polyethersulfone resin microporous filter membrane and a double-layer flat filter, respectively, and was overheated at a temperature of 51°C for at least 24h; Step 2, place the seed crystal 13 on the seed crystal holder 4, connect and fix the evaporation rate control cover 1, the funnel-shaped solvent evaporation pool 2, and the detachable long rod-shaped crystal growth tank 3 to assemble into an evaporation crystal growing device 7, put it into the crystal growth row bracket 11, and use the water bath liquid 12, the high-temperature heating device 16 and the low-temperature heating device 17 to preheat the evaporation crystal growing device 7 until the seed crystal 13 is preheated to a stable state at 37°C and lasts for at least 24 hours; Step 3, transferring the growth solution 5 to the evaporation crystal incubator 7, adjusting the high temperature heating device 16 to 42° C., and the low temperature heating device 17 to 36° C. so that the growth solution 5 in the evaporation crystal incubator 7 has a certain degree of supersaturation and obtains a growth driving force, adjusting the opening size of the evaporation speed control cover 1 so that the replenishment and consumption rates of the supersaturation are consistent, and the seed crystal 13 is controlled and stably grown in one-dimensional direction in the organic glass U-shaped groove A10 at a certain speed; Step 4, record and calculate the height of the seed crystal 13, adjust the height position of the heater in the low temperature insulation device 15 according to the actual height of the seed crystal 13, so that it is always located 13 cm above the crystal, and calculate the actual supersaturation consumption according to the volume of crystal growth, so as to adjust the set temperature of the high temperature insulation device 14 accordingly, so that the replenishment and consumption rates of the supersaturation are consistent; the growth rate of the crystal should be controlled to be 10 mm / day; Step 5: After the crystal grows to the expected size, set the high temperature insulation device 14 and the low temperature insulation device 15 to slowly lower the temperature at a cooling rate of 0.1°C / h. After the temperature reaches the ambient temperature, remove the funnel-shaped solvent evaporation pool 2, the detachable long rod-shaped crystal growth groove 3, and the silicone rubber sealant between the seed holder 4, and remove the organic glass cover 8 and the stainless steel screws of the stainless steel shell 9 to separate the organic glass U-shaped groove 10 containing the long rod-shaped KDP crystal inside, and finally obtain a 10mm*10mm*400mm long rod-shaped KDP crystal grown along a specific direction.

[0040] Performance test: The long rod-shaped KDP crystal samples prepared by the device and method of the present application were compared with the rod-shaped KDP crystal samples obtained by cutting the block crystal grown by the traditional device, and the crystal transmittance, second harmonic conversion efficiency and laser-induced damage threshold were tested. The results are as follows: Figure 5-7 shown. Figure 5-7In the figure, new sample preparation 1, 2, and 3 are samples prepared by the device of the present application; traditional sample preparation 1, 2, and 3 are samples prepared by traditional equipment. The raw material utilization rate is calculated respectively, and the results are as follows: Figure 8 shown.

[0041] The SHIMADZU 3600iPLUS UV-VIS-FIR spectrophotometer was used to test the crystal transmittance. At a wavelength of 1064nm, the samples prepared by the device of the present application had the same excellent optical uniformity as the samples prepared by traditional equipment.

[0042] The second harmonic conversion efficiency and laser-induced damage threshold were tested using a CONTINUUM Powerlite DLS 8000 pulsed laser with a 10ns 1064nm pulse laser. The beam diameter used in the test was 8mm and the single pulse energy was 828.7mJ. The second harmonic conversion efficiency of the crystal prepared by the device of the present application was comparable to that of the sample prepared by the traditional equipment. In the 1-on-1 laser-induced damage threshold test, the crystal prepared by the device of the present application was slightly improved compared to the traditional method.

[0043] It can be seen that the new device in the present application can increase the raw material utilization rate to nearly 100% while ensuring that the optical quality of the product is not lost, and obtain long rod-shaped KDP single crystals along a certain direction at a faster speed. The device is extremely small, thereby greatly reducing costs, improving yields, and shortening the growth cycle.

[0044] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. An evaporation method directional growth device for long rod-shaped KDP-based crystals, characterized in that: include: An evaporation crystal incubator and a water bath heating and heat preservation device, wherein the evaporation crystal incubator with built-in growth solution is fixedly placed in the water bath heating and heat preservation device; The bottom of the evaporation crystal incubator is a seed crystal holder, and the upper end is provided with a solvent evaporation pool, the solvent evaporation pool is installed on the seed crystal holder through a crystal growth groove, and a fluid channel connecting the seed crystal holder and the solvent evaporation pool is left in the crystal growth groove, and the fluid channel is a long rod-shaped cavity; The water bath heating and heat preservation device comprises: two sets of temperature control subsystems, and the heating and heat preservation ends of the temperature control subsystems are located outside the evaporation crystal incubator and are installed at different heights.

2. The evaporation method directional growth device for long rod-shaped KDP-based crystals according to claim 1, characterized in that: The heating and heat preservation end of one temperature control subsystem is placed outside the solvent evaporation pool, and the heating and heat preservation end of the other temperature control subsystem is placed outside the crystal growth tank.

3. The evaporation method directional growth device for long rod-shaped KDP-based crystals according to claim 2, characterized in that: The solvent evaporation pool is funnel-shaped.

4. The evaporation method directional growth device for long rod-shaped KDP-based crystals according to claim 3, characterized in that: The upper end of the solvent evaporation pool is open and is equipped with an evaporation rate control cover. The upper end of the solvent evaporation pool is also covered with a microporous semipermeable membrane. The evaporation rate control cover is located above the microporous semipermeable membrane.

5. The evaporation method directional growth device for long rod-shaped KDP-based crystals according to claim 4, characterized in that: The inclination angle of the solvent evaporation pool is 20°-30°; the diameter of the micropores of the microporous semipermeable membrane is less than 100 nanometers.

6. The directional growth device for long rod-shaped KDP-based crystals by evaporation method according to any one of claims 1 to 5, characterized in that: The temperature control subsystem comprises: a ring heater and a matching thermocouple, wherein one ring heater is installed through a fixed bracket standing in the water bath heating and heat preservation device, and the ring heater moves up and down along the crystal growth groove.

7. The evaporation method directional growth device for long rod-shaped KDP-based crystals according to claim 6, characterized in that: Also includes: The crystal cultivation device row bracket, the evaporation crystal cultivation device is arranged in parallel on the crystal cultivation device row bracket, and the crystal cultivation device row bracket is fixed in the water bath heating and heat preservation device.

8. The evaporation method directional growth device for long rod-shaped KDP-based crystals according to claim 6, characterized in that: In the crystal growth tank, a stainless steel shell is fixedly mounted on the organic glass cover plate, and a U-shaped groove is arranged between the organic glass cover plate and the stainless steel shell.

9. A method for directional growth of long rod-shaped KDP-based crystals by evaporation, characterized in that: Here are the steps: S1, in the preparation stage, firstly, the seed crystal is placed in the seed fixing groove at the bottom of the evaporation crystal growing device, and then the assembled and sealed evaporation crystal growing device is fixed in the water bath heating and heat preservation device, and the water bath heating and heat preservation device is started for preheating; S2, in the growth stage, the growth solution is injected into the solvent evaporation tank, and the heating and insulation temperatures of the two temperature control subsystems are respectively set. The heating and insulation temperature of the temperature control subsystem located outside the crystal growth tank is 1-2°C higher than the temperature corresponding to the saturated solution of the crystal material, and the heating and insulation temperature of the other temperature control subsystem is higher than the heating and insulation temperature of the temperature control subsystem located outside the crystal growth tank by more than 6°C, and the opening of the evaporation rate control cover is adjusted so that the replenishment and consumption rates of the supersaturation of the growth solution are consistent; S3, completion stage, after the crystal grows to the expected size, set the two temperature control subsystems to slowly cool down to the ambient temperature, and take out the long rod-shaped KDP crystal grown along a specific direction.

10. The method for directional growth of long rod-shaped KDP-based crystals by evaporation method according to claim 9, characterized in that: During the growth stage, the method further includes: adjusting the height of a heater of a temperature control subsystem located outside the crystal growth tank according to the height of the crystal so that the heater is located 10-15 cm above the crystal.

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