Crystal growth real-time monitoring method and monitoring system and application thereof

Abstract

The invention discloses a real-time monitoring method for crystal growth, belongs to the field of crystal growth, and solves the problems that in the prior art, whether a single crystal grows or not can be known only after the crystal growth is finished and the crystal is taken out after cooling, the growth process cannot be monitored in real time, and the crystal growth cost and efficiency are influenced. The method comprises the steps that collimation white light is emitted in the direction perpendicular to the crystal growth height, the collimation white light sequentially penetrates through a light-transmitting window in one side of a crystal growth furnace body, raw materials in a crucible and a light-transmitting window in the other side of the crystal growth furnace body, and an image of the crystal growth condition in the furnace body under irradiation of the collimation white light is collected in real time; analyzing the acquired image in real time, comparing the acquired image with a pre-calibrated three-primary-color signal intensity ratio, determining the start-stop time of a crystal growth program, and comparing and analyzing the three-primary-color signal intensity ratio of the color of the acquired image with a pre-calibrated calibration value to determine the start-stop time of the crystal growth program. Automatic program switching is carried out on nodes in the stages of material melting, growth and the like, so that automatic monitoring and / or control of the whole growth process are / is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of crystal growth, and in particular to a real-time crystal growth monitoring method and a monitoring system and application thereof. Background Art

[0002] The crucible-down method is the most important method for growing large single crystals. Scintillating crystals such as cesium iodide (CsI), sodium iodide (NaI), and lanthanum bromide (LaBr3) are all grown using this method. However, during crystal growth using the crucible-down method, the interface shape within the crucible cannot be observed during the growth process. Therefore, it is impossible to adjust growth conditions in real time based on the evolution of the crystallization interface. Currently, the only way to determine whether a single crystal has grown is after growth is complete, the crystal has been cooled, and then removed. This makes it impossible to monitor the growth process in real time, impacting both cost and efficiency. Summary of the Invention

[0003] In view of the above situation, the present invention aims to provide a real-time monitoring method for crystal growth and its monitoring system and application, which are used to solve at least one of the following problems: (1) The existing method for preparing large-size single crystals can usually only determine whether a single crystal has been grown after the crystal growth is completed and the crystal is cooled and taken out. It is impossible to monitor and / or control the growth process in real time, which affects the cost and efficiency of crystal growth; (2) The disadvantage of the existing real-time monitoring method is that it can only rely on the growth personnel to observe the collected images qualitatively in real time, and the system itself cannot quantify the data and thus cannot perform logical judgment and respond to the program. At the same time, the sensitivity of human judgment is poor, and it is difficult to accurately judge the state changes during the crystal growth process, resulting in a low yield rate.

[0004] The purpose of the present invention is mainly achieved through the following technical solutions:

[0005] A first aspect of the present invention provides a method for real-time monitoring of crystal growth, comprising the following steps:

[0006] S1, adding materials into the crystal growth crucible in the heating module to perform raw material synthesis in the crucible;

[0007] S2, emitting collimated white light in a direction perpendicular to the crystal growth height, the collimated white light sequentially passing through a light-transmitting window on one side of the crystal growth furnace, the raw material in the crucible, and a light-transmitting window on the other side of the crystal growth furnace, and collecting real-time images of the crystal growth inside the furnace under the illumination of the collimated white light;

[0008] S3. Analyze the collected images in real time, compare the intensity ratio of the three primary color signals of the color of the material in the crucible with the pre-calibrated intensity ratio of the three primary color signals, determine the start and stop timing of the crystal growth program, and perform in-situ annealing after the crystal growth program is completed.

[0009] Furthermore, the A value and B value are obtained by respectively collecting and calibrating the three primary color signal intensity ratio A of the raw material melting color and the three primary color signal intensity ratio B of the crystal crystallization color, and then the collected images are analyzed in real time. When the absolute value of the difference between all signal intensity ratios and the A value is ≤3%, the growth program is started, and when the absolute value of the difference between the signal intensity ratio and the B value is ≤3%, the growth program is ended.

[0010] Furthermore, the light intensity corresponding to the A value is 5mA±30μA.

[0011] Furthermore, the light intensity corresponding to the B value is 5 mA±30 μA.

[0012] Furthermore, the method also determines that cracks appear inside the crystal when the light intensity drops to at least 70% during the crystal growth process, and issues an alarm.

[0013] Furthermore, the method also includes: within a one-dimensional pixel in any horizontal direction, the signal intensity ratio of the area within a 5% radius around the center of the image acquisition area reaches a value A, and at the same time, the signal intensity ratio of the 5% radius length at any end point of the image acquisition area reaches a value B, and the crystallization interface is judged to be a concave interface and an alarm is issued.

[0014] Furthermore, in any program, when the light intensity of the signal decreases to below 70%, it is determined that the crucible is leaking and an alarm is issued.

[0015] A second aspect of the present invention provides a real-time monitoring system for crystal growth, the system comprising: a crystal growth unit, an image acquisition unit, and an electronic control unit;

[0016] The crystal growth unit comprises: a crystal growth furnace body 1, a heating module 2 arranged inside the crystal growth furnace body 1, a crystal growth crucible 3 arranged in the heating module 2, and light-transmitting windows A and B, which are arranged on the side wall of the crystal growth furnace body 1 and match the height of the crystal growth crucible 3, and the light-transmitting windows A and B are symmetrically arranged in a direction perpendicular to the crystal growth height;

[0017] The image acquisition unit includes: a collimated white light source 4 and an ultra-high-definition camera 5. The collimated white light source 4 sequentially and parallelly passes through a light-transmitting window A on one side of the crystal growth furnace body 1, the raw materials in the crystal growth crucible 3, and a light-transmitting window B on the other side of the crystal growth furnace body 1, and reaches the ultra-high-definition camera 5. The ultra-high-definition camera 5 contains a spectroscope for decomposing the collected image light into three primary colors of red, green, and blue through the spectroscope and projecting the light onto three independent sensors respectively.

[0018] The electronic control unit is an electronic control cabinet 6, which includes an image recognition module 7 and a growth control module 8. The image recognition module 7 is used to compare the collected three-primary color signal intensity ratio with the pre-calibrated three-primary color signal intensity ratio, and adjust the program in response to the growth control module 8.

[0019] Furthermore, the crystal growth unit further comprises: a lifting system 9 for adjusting the height of the crystal growth crucible 3 .

[0020] Furthermore, the widths of the light-transmitting window A and the light-transmitting window B are independently no less than the width of the crystal growth crucible 3 .

[0021] Furthermore, the heights of the light-transmitting windows A and B are not less than the height of the crystal growing in the crystal growth crucible 3 .

[0022] Furthermore, the light-transmitting window A and the light-transmitting window B are each independently made of at least two layers of hollow quartz glass or sapphire.

[0023] The third aspect of the present invention provides an application of the monitoring method described in the first aspect of the present invention or the monitoring system described in the second aspect of the present invention in real-time automatic monitoring of crystal growth.

[0024] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0025] (1) The present invention opens a light-transmitting window at the crystal growth interface position of the crystal growth furnace, and emits collimated white light in the direction perpendicular to the crystal growth height. The collimated white light sequentially passes through the light-transmitting window on one side of the crystal growth furnace body, the raw materials in the crucible, and the light-transmitting window on the other side of the crystal growth furnace body, and collects images of the crystal growth conditions inside the crystal growth furnace body under the irradiation of the collimated white light in real time, thereby solving the problem that the growth interface position and growth interface changes cannot be observed during the crystal growth process.

[0026] (2) By comparing and analyzing the signal intensity ratios of the three primary colors of the collected image with pre-calibrated values, program switching is performed at the nodes of each stage such as chemical reaction, growth, and annealing, thereby realizing automated monitoring and / or control of the entire growth process.

[0027] (3) Alarms are issued for problems such as crystal cracks, concave crystal interfaces, and crucible leakage that occur during the crystal growth process, and timely processing is carried out to reduce costs, improve crystal yield and production safety.

[0028] Other features and advantages of the present invention will be described in the following description, and part of them will become obvious from the description, or will be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the contents particularly pointed out in the written description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like parts throughout the drawings.

[0030] Figure 1 This is a schematic diagram of the real-time monitoring system for crystal growth provided by the present invention.

[0031] Reference numerals

[0032] 1. Crystal growth furnace; 2. Heating module; 3. Crystal growth crucible; 4. Collimated white light source; 5. Ultra-high-definition camera; 6. Electric control cabinet; 7. Image recognition module; 8. Growth control module. DETAILED DESCRIPTION

[0033] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention and are used to explain the principles of the present invention together with the embodiments of the present invention.

[0034] The crucible-drop method is the most important method for growing large single crystals. Scintillating crystals such as cesium iodide (CsI), sodium iodide (NaI), and lanthanum bromide (LaBr3) are all grown using the crucible-drop method. Existing large-scale single crystal production methods typically only determine whether a single crystal has been grown after the crystal has cooled and been removed from the crystal growth process. This prevents real-time monitoring and / or control of the growth process, impacting both cost and efficiency.

[0035] A first aspect of the present invention provides a method for real-time monitoring of crystal growth, comprising the following steps:

[0036] S1, adding materials into the crystal growth crucible in the heating module to perform raw material synthesis in the crucible;

[0037] S2, emitting collimated white light in a direction perpendicular to the crystal growth height, the collimated white light sequentially passing through a light-transmitting window on one side of the crystal growth furnace, the raw material in the crucible, and a light-transmitting window on the other side of the crystal growth furnace, and collecting real-time images of the crystal growth conditions inside the crystal growth furnace under the illumination of the collimated white light;

[0038] S3. The A value and B value are obtained by respectively collecting and calibrating the signal intensity ratio A of the three primary colors of the raw material melting color and the signal intensity ratio B of the three primary colors of the crystallization color. Then, the collected images are analyzed in real time. When the absolute value of the difference between all signal intensity ratios and the A value is ≤3%, the growth program is started. When the absolute value of the difference between the signal intensity ratio and the B value is ≤3%, the growth program is terminated and in-situ annealing is performed.

[0039] In the present invention, a light-transmitting window is opened at the crystal growth interface position of the crystal growth furnace, and collimated white light is emitted along the direction perpendicular to the crystal growth height. The collimated white light sequentially passes through the light-transmitting window on one side of the crystal growth furnace body, the raw materials in the crucible, and the light-transmitting window on the other side of the crystal growth furnace body. An image of the crystal growth situation inside the furnace body under the irradiation of the collimated white light is collected in real time, and then the signal intensity ratio is calculated according to a program, thereby solving the problem that the growth interface position and growth interface changes cannot be observed and controlled in real time during the crystal growth process.

[0040] In the present invention, the method is applicable to the growth process of transparent crystals such as cesium iodide (CsI), sodium iodide (NaI), lanthanum bromide (LaBr3), CLYC (Cs2LiYCl6), CLLB (Cs2LiLaBr6), lithium indium sulfide (LiInS2), and lithium indium selenide (LiInSe2).

[0041] In the present invention, it is understood that both CLYC and CLLB are scintillating crystals with a potassium cryolite structure.

[0042] In the present invention, it can be understood that the temperature of the raw materials when they are combined in the crucible is related to the melting point of the crystal. Generally, the temperature of the materials is 30-70°C higher than the melting point of the crystal. Exemplarily, in the present invention, the temperature of the raw materials when they are combined in the crucible is 600-800°C.

[0043] In the present invention, considering the identification of the visible light band, the wavelength range of the collimated white light is 380-780 nm.

[0044] In the present invention, the ratio of the three primary color signal intensities refers to the RGB ratio, specifically the relative intensity ratio of the red, green and blue color signals.

[0045] In the present invention, the A value and the B value are related to the type of crystal. The cesium iodide (CsI), sodium iodide (NaI), lanthanum bromide (LaBr3), CLYC (Cs2LiYCl6), CLLB (Cs2LiLaBr6), lithium indium sulfide (LiInS2), and lithium indium selenide (LiInSe2) crystals involved in the present invention are all transparent, but they still have color. Their transparency is usually represented by the Alpha channel. The Alpha channel value range is 0 to 255, where 0 represents complete transparency and 255 represents complete opacity. The color of the melt obtained during the formation process of the above crystals, especially after the fusion process, varies. For example, the melt of lanthanum bromide (LaBr3) is a transparent yellow with a transmittance of 75%. Its corresponding A value is (255, 240, 0), and the corresponding B value is (255, 240, 0, 191), where 191 is the value of the Alpha channel, which is used to represent the degree of transparency.

[0046] In order to more clearly describe the A value and B value corresponding to the melt of the above substances, the melt colors of different substances and the corresponding A values ​​are listed as follows: Specifically:

[0047] The color of the molten material corresponding to cesium iodide is light yellow, the transmittance is 75%, the corresponding A value is (255, 246, 143), and the B value is (255, 246, 143, 191).

[0048] The color of the molten material corresponding to sodium iodide is light yellow, the transmittance is 70%, the corresponding A value is (255, 250, 205), and the B value is (255, 250, 205, 179).

[0049] The color of the molten material corresponding to lithium indium sulfide is brown-yellow, the transmittance is 45%, the corresponding A value is (238, 154, 73), and the B value is (238, 154, 73, 115).

[0050] The color of the molten material corresponding to lithium indium selenide is brown, the transmittance is 50%, the corresponding A value is (160, 82, 45), and the B value is (160, 82, 45, 128).

[0051] The color of the molten material corresponding to CLYC is beige, the transmittance is 80%, the corresponding A values ​​are (255, 248, 225), and the B values ​​are (255, 248, 225, 204).

[0052] The color of the molten material corresponding to CLLB is orange, the transmittance is 83%, the corresponding A value is (255, 239, 186), and the corresponding B value is (255, 239, 186, 212).

[0053] In the present invention, specifically, when the absolute value of the difference between the ratio of all signal intensities and the A value is ≤3%, it is considered that the raw material has been melted from a colored melt to a transparent melt, at which point it is determined that the melt is finished and the growth program is started.

[0054] In the present invention, melting is considered complete when the absolute value of the difference between the ratio of all signal intensities and the A value is ≤3%. This is because, in practice, molten material may slightly absorb certain wavelengths of light due to the presence of unavoidable impurities, resulting in slight deviations in color. For example, some crystals may have weak absorption peaks at specific wavelengths, which can affect their RGB ratio. Therefore, after extensive research, the inventors have found that setting the absolute value of the difference between the ratio of all signal intensities and the A value to ≤3% can improve logical accuracy while ensuring the normal operation of the crystal growth process, thereby improving crystal growth quality and ensuring transparent crystals without cracks or bubbles.

[0055] In the present invention, crystal growth is considered complete when the absolute value of the difference between the signal intensity ratio and the B value is ≤3%. This is also because some inevitable impurities in the crystal slightly absorb certain wavelengths of light, resulting in slight deviations in the crystal's color. Therefore, setting the absolute value of the difference between the signal intensity ratio and the B value to ≤3% can improve logical accuracy and thus enhance crystal growth quality while ensuring the normal operation of the crystal growth process.

[0056] In the present invention, illustratively, taking cesium iodide as an example, the standard value of the three primary color signal intensity ratio of the raw material melt color is (255, 246, 143). Considering that the actual molten material may have slight absorption of certain wavelengths of light due to the presence of inevitable impurities, thereby causing its color performance to deviate slightly, the inventors have found through extensive research that when the error of the three primary color signal intensity ratio is controlled within 3%, satisfactory results can still be obtained. For example, when the standard value of the three primary color signal intensity ratio is (247, 239, 139) or (255, 253, 147), it can still be considered that the melt is finished and the growth program is started.

[0057] According to a preferred embodiment of the present invention, the melting is considered complete when the absolute value of the difference between the ratio of all signal intensities and the A value is 1-3%. The crystal growth is considered complete when the absolute value of the difference between the ratio of all signal intensities and the B value is 1-3%.

[0058] In the present invention, it is understood that the in-situ annealing refers to annealing the solid crystal to room temperature after the crystal growth is completed, after the temperature is slowly lowered to room temperature after being kept warm for 3-15 days, with a cooling rate of 3°C / h to 10°C / h.

[0059] According to the present invention, the method further determines that cracks have occurred inside the crystal and issues an alarm when the light intensity drops to at least 70% during the crystal growth process.

[0060] In the present invention, the light intensity is represented by the magnitude of the current measured by the photodiode, and a larger measured current indicates a larger light intensity.

[0061] In the present invention, when the system recognizes that a crack has occurred in the crystal and issues an alarm, the growth personnel can adjust the growth program by remelting or correcting the growth program.

[0062] According to the present invention, further, the method also includes: the method also includes: within a one-dimensional pixel in any horizontal direction, the signal intensity ratio of the area within a 5% radius around the center of the image acquisition area reaches a value A, and at the same time, the signal intensity ratio of the 5% radius length at any end point of the image acquisition area reaches a value B, the crystallization interface is judged to be a concave interface, and an alarm is issued.

[0063] In the present invention, if the signal intensity ratio of the area within a 5% radius around the center of the image acquisition area in a one-dimensional pixel in any horizontal direction reaches a value A, and the signal intensity ratio of a 5% radius length at any end point of the image acquisition area reaches a value B, it is considered that a concave interface has appeared in the crystallization process and an alarm is promptly issued to feedback the crystal growth situation, so that the growth personnel can adjust and correct the growth program in time.

[0064] According to the present invention, the method further includes: in any program, when the ratio of the three primary color signal intensities of the signal is not within the calibration range, it is determined that the crucible is leaking and an alarm is issued.

[0065] In the present invention, the three primary color signal intensity ratio of the signal is not within the calibration range means that the three primary color signal intensity ratio of the signal does not meet the A value or the B value, that is, other colors other than the color of the crystal to be measured appear.

[0066] In the present invention, when the ratio of the three primary color signal intensities of the collected signals is out of the calibration range during the material processing and / or crystal growth process, it is determined that the crucible is leaking and an alarm is issued in time to feedback the crystal growth situation.

[0067] It is understandable that when the crucible leaks, the raw materials react with water vapor and oxygen in the air to produce colored gas, so production personnel need to deal with it in a timely manner to avoid safety accidents. In the present invention, the method can quickly identify the leakage and respond to the alarm in time, which can avoid potential safety hazards and improve production safety.

[0068] A second aspect of the present invention provides a real-time monitoring system for crystal growth, the system comprising: a crystal growth unit, an image acquisition unit, and an electronic control unit;

[0069] The crystal growth unit comprises: a crystal growth furnace body 1, a heating module 2 arranged inside the crystal growth furnace body 1, a crystal growth crucible 3 arranged in the heating module 2, and light-transmitting windows A and B, which are arranged on the side wall of the crystal growth furnace body 1 and match the height of the crystal growth crucible 3, and the light-transmitting windows A and B are symmetrically arranged in a direction perpendicular to the crystal growth height;

[0070] The image acquisition unit includes: a collimated white light source 4 and an ultra-high-definition camera 5. The collimated white light source 4 sequentially and parallelly passes through a light-transmitting window A on one side of the crystal growth furnace body 1, the raw materials in the crystal growth crucible 3, and a light-transmitting window B on the other side of the crystal growth furnace body 1, and reaches the ultra-high-definition camera 5. The ultra-high-definition camera 5 contains a spectroscope for decomposing the collected image light into three primary colors of red, green, and blue through the spectroscope and projecting the light onto three independent sensors respectively.

[0071] The electronic control unit is an electronic control cabinet 6, which includes: an image recognition module 7 and a growth control module 8. The image recognition module 7 is used to compare the collected three-primary color signal intensity ratio with the pre-calibrated three-primary color signal intensity ratio, and at the same time respond to the growth control module 8 to adjust the program.

[0072] In the present invention, the system includes a crystal growth unit, an image acquisition unit and an electronic control unit, and can provide equipment support for a "dark factory" that automates the crystal growth process.

[0073] In the present invention, a crystal growth furnace body 1 in a crystal growth unit includes a heating module 2 disposed inside the crystal growth body 1 , and a crystal growth crucible 3 is disposed in the heating module 2 for supporting raw material.

[0074] A light-transmitting window A and a light-transmitting window B are provided on the side wall of the crystal growth furnace body 1, which are matched with the height of the crystal growth crucible 3. The light-transmitting window A and the light-transmitting window B are symmetrically arranged in a direction perpendicular to the crystal growth height, so that the collimated white light outside the crystal growth furnace body 1 can pass through the light-transmitting window A and the light-transmitting window B to project the image of the crystal growth process irradiated by the collimated white light outside the crystal growth furnace body 1 into the ultra-high-definition camera, thereby realizing the visualization of the crystal growth. At the same time, the collected image light is decomposed into the three primary colors of red, green and blue through a spectroscope and the signal intensity ratio is obtained, so that the subsequent image recognition module 7 can compare and process the collected three primary color signal intensity ratios.

[0075] Furthermore, in order to facilitate observation of crystal growth, the crystal growth unit is further provided with a lifting system 9 for adjusting the height of the crystal growth crucible 3 .

[0076] In the present invention, further, considering the improvement of the thermal insulation effect of the crystal growth furnace body 1 under the premise of ensuring light transmittance, the materials of the light-transmitting window A and the light-transmitting window B are each independently made of at least two layers of hollow quartz glass or sapphire, and at the same time, the widths of the light-transmitting window A and the light-transmitting window B are each independently not less than the width of the crystal growth crucible 3, and the heights of the light-transmitting window A and the light-transmitting window B are not less than the height of the crystal growth in the crystal growth crucible 3.

[0077] Specifically, in the present invention, the image acquisition unit comprises a collimated white light source 4, an ultra-high-definition camera 5, light-transmitting window A, and light-transmitting window B, with the collimated white light source 4 and light-transmitting window A positioned at a distance of 1-5 cm, and the ultra-high-definition camera 5 and light-transmitting window B positioned at a distance of 1-5 m. This ensures that the imaging effect is maintained, ensuring that the material within the crystal growth crucible 3 is completely within the field of view and that details are clearly visible, thereby providing more accurate information.

[0078] According to a preferred embodiment of the present invention, the distance between the collimated white light source 4 and the light-transmitting window A is 2-3 cm, and the distance between the ultra-high-definition camera 5 and the light-transmitting window B is 2-3 cm.

[0079] The collimated white light source 4 passes through the light-transmitting window A on one side of the crystal growth furnace body 1, the raw materials in the crystal growth crucible 3 and the light-transmitting window B on the other side of the crystal growth furnace body 1 in parallel in sequence, and reaches the ultra-high-definition camera 5. The ultra-high-definition camera 5 contains a spectrometer, which is used to decompose the collected image light into three primary colors of red, green and blue through the spectrometer and project them onto three independent sensors in the image recognition module 7 respectively. It can be understood that the sensor is located inside the camera 6.

[0080] In the present invention, specifically, the image recognition module 7 performs real-time analysis on the collected image and the signal intensity ratio of the three primary colors. When the absolute value of the difference between the collected signal intensity ratio and the A value is ≤3%, the growth program is started. When the absolute value of the difference between the collected signal intensity ratio and the B value is ≤3%, the growth program is ended and in-situ annealing is performed.

[0081] In the present invention, specifically, the growth control module 8 can perform program switching at the nodes of each stage such as chemical reaction, growth, and annealing, thereby realizing automatic monitoring and / or control of the entire growth process.

[0082] The third aspect of the present invention provides an application of the control method described in the first aspect of the present invention or the control system described in the second aspect of the present invention in real-time automatic control of crystal growth.

[0083] Compared to methods that rely on real-time qualitative observation of collected images by growth personnel, which cannot quantify data and thus cannot make logical judgments and respond to programs, and the poor sensitivity of human judgment makes it difficult to accurately judge state changes during crystal growth, resulting in a still low yield rate, the real-time crystal growth monitoring system provided by the present invention can determine the start and stop timing of the crystal growth program. By comparing and analyzing the signal intensity ratios of the three primary colors of the collected images with pre-calibrated calibration values, the program automatically switches at nodes such as the material synthesis and growth stages, thereby realizing automated monitoring and / or control of the entire growth process.

[0084] The advantages of precise parameter control of the present invention are demonstrated below with specific examples and comparative examples.

[0085] Example 1

[0086] The color of the melt of cesium iodide, a type of crystal to be tested, is pre-calibrated to have an A value of (255, 246, 143) and a B value of (255, 246, 143, 191).

[0087] S1, adding cesium iodide to the crystal growth crucible in the heating module to perform raw material synthesis in the crucible, and the crucible is placed on a lifting system;

[0088] S2. Emitting collimated white light in a direction perpendicular to the height of the crystal growth, the collimated white light sequentially passes through a light-transmitting window A on one side of the crystal growth furnace body, the raw materials in the crucible, and a light-transmitting window B on the other side of the crystal growth furnace body, and real-time capturing images of the crystal growth inside the furnace body under the illumination of the collimated white light, wherein the distance between the collimated white light source and the light-transmitting window is 2 cm, and the distance between the light-transmitting window on the other side of the crystal growth furnace body and the camera is 2 cm, the light-transmitting window A and the light-transmitting window B are each independently made of two layers of hollow quartz glass; the width and height of the light-transmitting window A and the light-transmitting window B are each independently matched with the width and height of the crystal growing in the crystal growth crucible;

[0089] S3. Using the spectroscope in the ultra-high-definition camera 5, the incident light of the captured image is decomposed into the three primary colors of red, green, and blue and projected onto three independent sensors respectively. The image recognition module receives the signal intensity ratio value of the three primary colors of the incident light and performs real-time analysis. When the A value of the color of the material in the crucible collected is (247, 239, 139), the corresponding light intensity is 5 mA, and the light intensity does not change, it is compared with the pre-calibrated three-primary color signal intensity ratio (255, 246, 143), and the error is 3%, it is determined that the melt is finished, and the growth control module is responded to start the growth program. When the B value of the color of the material in the crucible collected is (247, 239, 139, 190), the corresponding light intensity is 5 mA, and the light intensity does not change, it is determined that the crystal growth is finished, and the growth control module is responded to automatically end the crystal growth program. Then, the solid crystal in the crucible is kept warm for 5 days and then cooled to room temperature at a cooling rate of 5°C / h for in-situ annealing to obtain a cesium iodide crystal.

[0090] Example 2

[0091] The color of the melt of sodium iodide, a type of crystal to be tested, is pre-calibrated to have an A value of (255, 250, 205) and a B value of (255, 250, 205, 179).

[0092] S1. Add sodium iodide to the crystal growth crucible in the heating module to chemically react the raw materials in the crucible. The crucible is placed on a lifting system.

[0093] S2. Emitting collimated white light in a direction perpendicular to the height of the crystal growth, the collimated white light sequentially passes through a light-transmitting window A on one side of the crystal growth furnace body, the raw materials in the crucible, and a light-transmitting window B on the other side of the crystal growth furnace body, and real-time capturing images of the crystal growth inside the furnace body under the illumination of the collimated white light, wherein the distance between the collimated white light source and the light-transmitting window is 2 cm, and the distance between the light-transmitting window on the other side of the crystal growth furnace body and the camera is 2 cm, the light-transmitting window A and the light-transmitting window B are each independently made of two layers of hollow quartz glass; the width and height of the light-transmitting window A and the light-transmitting window B are each independently matched with the width and height of the crystal growing in the crystal growth crucible;

[0094] S3. Use the spectroscope in the ultra-clear camera 5 to decompose the incident light of the captured image into three primary colors of red, green and blue and project them onto three independent sensors respectively. The image discrimination module receives the signal intensity ratio of the three primary colors of the incident light and performs real-time analysis. When the A value of the color of the material in the crucible collected is (245, 237, 138), the corresponding light intensity is 5mA, and the light intensity does not change, it is compared with the pre-calibrated three primary color signal intensity ratio (255, 250, 205). The error is 1%, and it is determined that the melt is finished, and the growth control module is responded to start the growth program. When the B value of the color of the material in the crucible collected is (245, 237, 138), the corresponding light intensity is 5mA, and the light intensity does not change, it is compared with the pre-calibrated three primary color signal intensity ratio (255, 250, 205). The error is 1%. The values ​​are (245, 237, 138, 191), corresponding to a light intensity of 5mA. At this time, the light intensity begins to decrease. When it drops to 3.5mA, the system determines that the crystal has cracks and issues an alarm. The growth personnel adjust the growth temperature and restart the growth program. When the B value of the color of the material in the crucible is (245, 237, 138, 191), corresponding to a light intensity of 5mA, and the light intensity does not change, it is determined that the crystal growth is completed. The response growth control module automatically ends the crystal growth program and then keeps the solid crystal in the crucible warm for 5 days, then cools it to room temperature at a cooling rate of 5°C / h for in-situ annealing to obtain sodium iodide crystals.

[0095] Example 3

[0096] The color of the melt of cesium iodide, a type of crystal to be tested, is pre-calibrated to have an A value of (255, 246, 143) and a B value of (255, 246, 143, 191).

[0097] S1. Add cesium iodide to the crystal growth crucible in the heating module to chemically react the raw materials in the crucible. The crucible is placed on a lifting system.

[0098] S2. Emitting collimated white light in a direction perpendicular to the height of the crystal growth, the collimated white light sequentially passes through a light-transmitting window A on one side of the crystal growth furnace body, the raw materials in the crucible, and a light-transmitting window B on the other side of the crystal growth furnace body, and real-time capturing images of the crystal growth inside the furnace body under the illumination of the collimated white light, wherein the distance between the collimated white light source and the light-transmitting window is 2 cm, and the distance between the light-transmitting window on the other side of the crystal growth furnace body and the camera is 2 cm, the light-transmitting window A and the light-transmitting window B are each independently made of two layers of hollow quartz glass; the width and height of the light-transmitting window A and the light-transmitting window B are each independently matched with the width and height of the crystal growing in the crystal growth crucible;

[0099] S3. Using the spectroscope in the ultra-high-definition camera 5, the incident light of the captured image is decomposed into the three primary colors of red, green, and blue, and the images are projected onto three independent sensors. The discrimination module receives the signal intensity ratios of the three primary colors of the incident light and performs real-time analysis. When the A value of the color of the material in the crucible collected is (204, 153, 255) (the RGB corresponding color is light purple, i.e., purple gas appears), it is considered that the color other than the melt and crystal appears, and the crucible is judged to be leaking. An alarm is issued, and the crystal growth has failed. The growth process is stopped, saving electricity and personnel costs.

[0100] Comparative Example 1

[0101] The currently used growth method is a closed growth method for growing cesium iodide crystals, that is, in a growth furnace without a window. Specifically, by controlling the temperature of the upper temperature zone to 690°C and the temperature of the lower temperature zone to 100°C, after loading the furnace, the temperature is raised to 560°C, and after being kept at 560°C for 5 hours, the growth program is started, and the crucible descends at a speed of 30 mm / d. After the growth is completed, the growth program is terminated and the temperature is lowered to room temperature within 20 hours for annealing.

[0102] This method can only take out the crystal after the annealing is completed to confirm the crystal growth situation. Any problems that arise during the process can only be judged by the crystal morphology after being taken out of the furnace. It is impossible to obtain information about the growth process and it is impossible to effectively intervene in the process. Compared with the method provided by the present invention, the yield rate is lower, the consumption of time and electricity is not scientifically controlled, and it is an extensive growth model.

[0103] The methods of Example 1 and the comparative example were repeated 20 times, and the yield rates were calculated and shown in Table 2. Crystals with defects such as cracks, scratches, pits, and holes were considered defective, while crystals without such defects were considered finished products. The percentage of finished products to the total number of crystals was the yield rate.

[0104] Table 1

[0105] serial number Yield / % Example 1 90 Comparative Example 1 60

[0106] In Example 3, when the crucible leaks and growth failure is discovered midway, even if the process is stopped, electricity costs and labor costs are still saved. The crystal growth method according to Comparative Example 1 requires 100 hours of work. However, the crystal growth method according to Example 1 requires only 10 hours of work. The traditional growth method is closed growth, and people cannot observe the growth process. It is necessary to manually switch the program at each time point. After the annealing program is completed, the crystal is taken out of the furnace and the growth result is confirmed, resulting in a waste of resources.

[0107] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered by the scope of protection of the present invention.

Claims

1. A method for real-time monitoring of crystal growth, characterized in that: The following steps are involved: S1, adding materials into the crystal growth crucible in the heating module to perform raw material synthesis in the crucible; S2, emitting collimated white light in a direction perpendicular to the crystal growth height, the collimated white light sequentially passing through a light-transmitting window on one side of the crystal growth furnace, the raw material in the crucible, and a light-transmitting window on the other side of the crystal growth furnace, and collecting real-time images of the crystal growth inside the furnace under the illumination of the collimated white light; S3. Analyze the collected images in real time, compare the intensity ratio of the three primary color signals of the color of the material in the crucible with the pre-calibrated intensity ratio of the three primary color signals, determine the start and stop timing of the crystal growth program, and perform in-situ annealing after the crystal growth program is completed.

2. The monitoring method according to claim 1, characterized in that: The A value and B value are obtained by respectively collecting and calibrating the signal intensity ratio A of the three primary colors of the raw material melting color and the signal intensity ratio B of the three primary colors of the crystallization color; when the absolute value of the difference between the signal intensity ratio and the A value is ≤3%, the growth program is started, and when the absolute value of the difference between the signal intensity ratio and the B value is ≤3%, the growth program is ended.

3. The monitoring method according to claim 2, characterized in that: The light intensity corresponding to the A value is 5mA±30μA; And / or, the light intensity corresponding to the B value is 5 mA±30 μA.

4. The monitoring method according to claim 1 or 2, characterized in that: The method also determines that cracks and / or bubbles appear inside the crystal when the light intensity drops to at least 70% during the crystal growth process, and issues an alarm.

5. The monitoring method according to claim 1 or 2, characterized in that: The method further includes: if, within a one-dimensional pixel in any horizontal direction, the signal intensity ratio of an area within a 5% radius around the center of the image acquisition area reaches a value A, and the signal intensity ratio of a 5% radius length at either end of the image acquisition area reaches a value B, determining that the crystallization interface is a concave interface and issuing an alarm; And / or, in any program, when the ratio of the three primary color signal intensities is not within the calibration range, it is determined that the crucible is leaking and an alarm is issued.

6. A real-time monitoring system for crystal growth, characterized in that: The system includes: a crystal growth unit, an image acquisition unit and an electronic control unit; The crystal growth unit comprises: a crystal growth furnace body (1), a heating module (2) arranged inside the crystal growth furnace body (1), a crystal growth crucible (3) arranged in the heating module (2), and a light-transmitting window A and a light-transmitting window B, which are matched with the height of the crystal growth crucible (3), are opened on the side wall of the crystal growth furnace body (1), and the light-transmitting window A and the light-transmitting window B are symmetrically arranged in a direction perpendicular to the crystal growth height. The image acquisition unit comprises: a collimated white light source (4) and an ultra-high-definition camera (5); the collimated white light source (4) sequentially and parallelly passes through a light-transmitting window A on one side of a crystal growth furnace body (1), raw materials in a crystal growth crucible (3), and a light-transmitting window B on the other side of the crystal growth furnace body (1), and reaches the ultra-high-definition camera (5); the ultra-high-definition camera (5) contains a spectroscope for decomposing the collected image light into three primary colors of red, green, and blue through the spectroscope and projecting the light onto three independent sensors respectively; The electric control unit is an electric control cabinet (6), comprising an image discrimination module (7) and a growth control module (8). The image discrimination module (7) is used to compare the intensity ratio of the collected three primary color signals with the pre-calibrated intensity ratio of the three primary color signals, and simultaneously adjust the program in response to the growth control module (8).

7. The monitoring system according to claim 6, characterized in that The crystal growth unit further comprises a lifting system (9) for adjusting the height of the crystal growth crucible (3).

8. The monitoring system according to claim 6 or 7, characterized in that: The widths of the light-transmitting window A and the light-transmitting window B are independently no less than the width of the crystal growth crucible (3); And / or, the heights of the light-transmitting window A and the light-transmitting window B are not less than the height of the crystal growing in the crystal growth crucible (3).

9. The monitoring system according to claim 6 or 7, characterized in that: The light-transmitting window A and the light-transmitting window B are each independently made of at least two layers of hollow quartz glass or sapphire.

10. Use of the real-time crystal growth monitoring method according to any one of claims 1 to 5 in the monitoring system according to any one of claims 6 to 9.

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