Single crystal furnace liquid level positioning device based on inverted image feature recognition and single crystal furnace

Abstract

The utility model relates to monocrystal silicon production technical field, more particularly, a kind of monocrystal furnace liquid level positioning device and monocrystal furnace based on inverted image feature recognition, comprising: feature plate, the feature plate is horizontally installed in the outside of flow guide cylinder, the feature plate has openwork structure, for forming stable inverted image on the liquid level of silicon liquid in crucible;Image processing module is used to extract the corner point coordinates in the inverted image, and according to the deformation variable of the inverted image, the liquid level height variation ΔH is calculated.It can adopt machine vision scheme, improve inverted image forming capability, improve inverted image recognition robustness.

Description

Technical Field

[0001] This utility model relates to the field of monocrystalline silicon production technology, and more specifically, to a monocrystalline furnace liquid level positioning device and a monocrystalline furnace based on reflection feature recognition. Background Technology

[0002] In the production of monocrystalline silicon, accurate measurement of the liquid level height (liquid gate distance) is crucial because it directly affects crystal quality and the consistency of the growth process. Several commonly used methods for measuring liquid gate distance include: (1) Contact probe: molybdenum / tungsten metal probes are installed on the side wall of the guide tube or the inner wall of the water-cooled screen. Disadvantages: 1. The probe is easy to contaminate the melt; 2. Frequent calibration is required; 3. Not suitable for large-size single crystals (large-size single crystals have large liquid level fluctuations). (2) Laser triangulation method: A laser transmitter / receiver is installed outside the observation window to measure the displacement of the reflected spot of the laser beam on the liquid surface. Disadvantages: 1. Steam interference causes spot shift (actual measurement error ±1.5mm); 2. The optical window needs forced cooling (increases energy consumption by 30%); 3. The equipment cost is high (single set > 120,000 yuan). (3) Machine vision solution: industrial camera captures liquid reflection, image processing recognizes preset marks (such as the edge of the guide tube). Disadvantages: 1. Liquid surface shaking causes feature points to become blurred (recognition failure rate > 15%); 2. Dedicated supplementary light is required (furnace temperature limits lamp life < 2000h); 3. Data processing delay (average response time 800ms). Utility Model Content

[0003] The purpose of this invention is to provide a single crystal furnace liquid level positioning device based on reflection feature recognition, which can adopt a machine vision solution to improve reflection imaging capability and enhance the robustness of reflection image recognition.

[0004] Another objective of this invention is to provide a single crystal furnace that can adopt a machine vision solution to improve reflection imaging capability and enhance the robustness of reflection image recognition.

[0005] The technical solution of this utility model is implemented as follows: A liquid level positioning device for a single crystal furnace based on reflection feature recognition, wherein the single crystal furnace has a crucible and a guide tube, and a circular liquid inlet is opened at the center of the bottom of the guide tube, comprising: A feature plate, which is horizontally mounted on the outside of the guide tube, has a hollow structure for forming a stable reflection on the surface of the molten silicon in the crucible; The image processing module is used to extract the coordinates of the corner points in the reflection and calculate the change in liquid level height ΔH based on the deformation of the reflection.

[0006] Furthermore, the hollow structure uses rectangular holes.

[0007] Furthermore, the hollow structure of the feature plate is designed as a rectangular hole of 4mm×8mm to enhance reflection contrast and corner stability.

[0008] Furthermore, it also includes a connecting structure, which includes an upper clamping plate and an intermediate connecting plate. The upper clamping plate, the intermediate connecting plate, and the feature plate are connected in sequence to form a C-shaped bending structure. The opening groove of the C-shaped bending structure is correspondingly clamped to the edge of the liquid outlet, and the upper clamping plate is located at the upper edge of the liquid outlet. The intermediate connecting plate is correspondingly attached to the inner wall of the liquid outlet, and the feature plate is located at the lower edge of the liquid outlet.

[0009] Furthermore, the upper edge of the liquid inlet is provided with a support ring mounting groove for mounting a support ring. The upper clamping plate is correspondingly fitted to the bottom wall of the support ring mounting groove. The upper clamping plate is provided with a circular mounting hole. The C-shaped bending structure is connected to the guide tube through the circular mounting hole to form a flange connection, which is used to ensure that the feature plate and the liquid surface maintain a constant relative position.

[0010] Furthermore, the circular mounting hole and the hollow structure are coupled to ensure a tight fit between the feature plate and the guide tube.

[0011] Furthermore, the feature plate is made of molybdenum or a molybdenum alloy.

[0012] Furthermore, the feature plate is made of a forged molybdenum alloy with a surface roughness of Ra0.8μm.

[0013] Furthermore, the hollow structure adopts cross-shaped holes or diamond-shaped holes, and the hollow ratio can be adjusted to adapt to different melt characteristics requirements.

[0014] A single crystal furnace, including the single crystal furnace liquid level positioning device.

[0015] Compared with the prior art, the beneficial effects of this utility model are: This application provides a liquid surface positioning device for a single crystal furnace based on reflection feature recognition. A feature plate with a hollow structure is installed on the outside of the guide tube to form a stable reflection on the liquid surface. The specific liquid surface positioning includes the following steps: The reflection of the feature plate is imaged through the observation window to the image processing module (e.g., a CCD camera); The coordinates of corner points in the reflection are extracted using an image processing module; The change in liquid level ΔH is calculated by the reflection deformation and fed back to the lifting mechanism of the single crystal furnace to achieve automatic adjustment of the crucible position.

[0016] This device utilizes the anti-interference properties of the corner points of the hollow structure on the feature plate (resisting liquid surface shaking and silicon sputtering), increases the features for acquiring in-furnace reflection images, reduces blurring of feature points due to liquid surface shaking, improves the success rate of the crucible setting process, ensures consistency of liquid outlet distance, enhances reflection imaging capabilities, and improves image recognition robustness. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram showing the positional relationship between the crucible and the guide tube of this utility model; Figure 2 This utility model Figure 1 Enlarged view of the structure at point A in the middle; Figure 3 This is a cross-sectional view of the guide tube of this utility model; Figure 4 This is a schematic diagram of the C-shaped bending structure of this utility model.

[0019] In the picture: 1-Guide tube; 101-Liquid port; 102-Support ring mounting groove; 2-Crucible; 3-Support ring; 4-C-shaped bending structure; 401-feature plate; 4011-hollow structure; 402-intermediate connecting plate; 403-upper clamping plate; 4031-circular mounting hole. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0022] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0023] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this utility model is in use. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0024] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0025] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0026] The following detailed description, in conjunction with the accompanying drawings, outlines some embodiments of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0027] Example 1 Reference Figures 1-4 This embodiment provides a liquid level positioning device for a single crystal furnace based on reflection feature recognition. The single crystal furnace has a crucible 2 and a guide cylinder 1. A circular liquid outlet 101 is opened at the center of the bottom of the guide cylinder 1. The liquid level positioning device includes: Feature plate 401, which is horizontally installed on the outside of guide tube 1, has a hollow structure 4011 for forming a stable reflection on the surface of the silicon liquid in crucible 2. The image processing module is used to extract the coordinates of the corner points in the reflection and calculate the change in liquid level height ΔH based on the deformation of the reflection.

[0028] Specifically, the cutout structure 4011 on the feature plate 401 adopts a rectangular hole, and the cutout structure 4011 is designed as a 4mm×8mm rectangular hole (the size is adapted to 8-12 inch crystal rods). Its rectangular cutout structure 4011 can form a stable reflection on the surface of the molten silicon. Furthermore, by utilizing the anti-interference characteristics of the rectangular corner points (resisting liquid surface vibration and silicon sputtering), the robustness of image recognition is improved, and the stability of the corner points is enhanced. By utilizing the anti-interference characteristics of the square corner points, the stability of the reflected feature points can be maintained even if there are fluctuations in the liquid surface.

[0029] The feature plate 401 can be made of molybdenum or a molybdenum alloy. The molybdenum feature plate 401 has a service life of more than 3 years and does not require frequent replacement of consumables. Preferably, the feature plate 401 is made of a forged molybdenum alloy with a surface roughness of Ra0.8μm. This material can not only withstand high temperature environments up to 1600℃, but also provide accurate reflection imaging effects.

[0030] The liquid level positioning device also includes a connecting structure, which includes an upper clamping plate 403 and an intermediate connecting plate 402. The upper clamping plate 403, the intermediate connecting plate 402, and the feature plate 401 are connected in sequence to form a C-shaped bending structure 4. The opening groove of the C-shaped bending structure 4 is correspondingly clamped to the edge of the liquid outlet 101, and the upper clamping plate 403 is located at the upper edge of the liquid outlet 101. The curvature of the intermediate connecting plate 402 is consistent with the curvature of the liquid outlet 101, so that the intermediate connecting plate 402 is correspondingly attached to the inner wall of the liquid outlet 101. The feature plate 401 is located at the lower edge of the liquid outlet 101.

[0031] Specifically, the upper edge of the liquid inlet 101 is provided with a support ring mounting groove 102 for mounting the support ring 3. The upper clamping plate 403 is correspondingly fitted to the bottom wall of the support ring mounting groove 102. The upper clamping plate 403 has a circular mounting hole 4031. The C-shaped bending structure 4 is flange-connected to the guide cylinder 1 through the circular mounting hole 4031 to ensure that the feature plate 401 and the liquid surface maintain a constant relative position. The circular mounting hole 4031 is a hole for fixing the C-shaped bending structure 4. The diameter of the circular mounting hole 4031 can be designed to be 5mm. Specifically, a hole can be opened on the bottom wall of the support ring mounting groove 102 of the guide cylinder 1, corresponding to the circular mounting hole 4031. Then, graphite bolts are used to fix the C-shaped bending structure 4 to the guide cylinder 1.

[0032] The circular mounting hole 4031 and the hollow structure 4011 are coupled to ensure a tight fit between the feature plate 401 and the guide tube 1.

[0033] By utilizing the anti-interference characteristics of the square corner points of the hollow structure 4011 on the feature plate 401 (resisting liquid surface shaking and silicon sputtering), the feature of the furnace reflection image acquisition is increased, the blurring of feature points caused by liquid surface shaking is reduced, the success rate of the crucible positioning process is improved, the consistency of the liquid outlet 101 distance is ensured, the reflection imaging capability is improved, and the robustness of image recognition is enhanced.

[0034] It should be noted that: (1) The above-mentioned "improving the robustness of image recognition" refers to enhancing the adaptability of image recognition algorithms or systems to external interference and changes, so that they can maintain high recognition accuracy and stability under various complex conditions. "Robustness" is mainly reflected in the following aspects: 1. Resistance to Liquid Surface Fluctuations: The liquid surface inside a single crystal furnace may fluctuate due to factors such as temperature and flow. Traditional machine vision solutions are prone to blurring feature points under these conditions, thus reducing the recognition success rate. However, this application addresses this issue by installing a molybdenum feature plate 401 on the outside of the guide tube 1 and using a square hollow structure 4011 to form a stable reflection. Even with slight fluctuations in the liquid surface, the square corner points in the reflection can still be clearly identified.

[0035] 2. Resistance to the effects of silicon sputtering: During the operation of a single crystal furnace, molten metal splashes (i.e., silicon sputtering) may obscure the lens or reflection area, interfering with image recognition. This application utilizes the anti-interference characteristics of square corner points, ensuring that even if part of the reflection is obscured, the algorithm can still accurately identify the image based on the remaining visible corner points.

[0036] 3. Enhanced adaptability to environmental changes: The internal environment of a single crystal furnace is complex, and factors such as changes in light and temperature fluctuations may exist. This application uses a forged molybdenum alloy with a surface roughness of Ra0.8μm as the material for the feature plate 401. This material is not only resistant to high temperatures, but also provides a stable reflection imaging effect, thereby reducing the interference of environmental changes on image recognition.

[0037] In simple terms, "improving image recognition robustness" means making the image recognition system more "resilient," maintaining high accuracy and success rate even when faced with liquid surface fluctuations, silicon sputtering, or other environmental changes. For example: If the liquid surface sloshes, traditional methods may fail to identify the feature points, but the square corner points of this solution can still be identified.

[0038] If molten material splashes partially obscure the reflection, traditional methods may fail, but this approach can continue to identify the image using the unobstructed portion.

[0039] Through these design improvements, this solution significantly enhances the stability and reliability of the image recognition system, thereby better meeting the actual needs of liquid level positioning in single crystal furnaces.

[0040] (2) The “corner coordinates” mentioned above refer to the specific location information of feature points in the image, usually represented in the form of coordinates on a two-dimensional plane (such as (x,y)). These corner points are key feature points extracted from the reflection image by image processing algorithms and used for subsequent calculations and analysis. Specifically, in this scheme, the “corner coordinates” refer to the location information of the four corner points of the molybdenum feature plate 401 square hollow structure 4011 in the reflection of the liquid surface. These corner points have the following characteristics and significance: 1. What is a corner point? Corner points are points in an image that possess distinct geometric characteristics; they are typically the vertices formed by the intersection of two straight lines. For example: In the reflection of the square hollow structure 4011, the four corner points are the four vertices of the square.

[0041] These corner points have high contrast and sharpness in the image, making them ideal as reference points for image recognition and localization.

[0042] 2. Uses of corner coordinates In this application, the corner coordinates of the reflection are extracted for the following reasons: Calculate the change in liquid level height: By comparing the changes in the corner positions of the currently captured reflection and the reference reflection, the change in liquid level height ΔH can be calculated.

[0043] Automatic adjustment is achieved by feeding back the calculated ΔH to the lifting mechanism of the single crystal furnace, thereby automatically adjusting the position of crucible 2 to ensure the consistency of the distance between liquid outlet 101 and the crucible 2.

[0044] 3. How to extract corner coordinates The process of extracting corner coordinates typically relies on image processing algorithms, such as: - Harris corner detection algorithm: used to detect the location of corners in an image.

[0045] - Shi-Tomasi Corner Detection Algorithm: An improved corner detection method that can extract feature points more stably.

[0046] - Vision libraries such as OpenCV or Halcon: These tools provide mature corner detection capabilities that can be directly applied to the image processing module of this solution.

[0047] 4. Why choose square corner points? Square corner points have the following advantages: Strong anti-interference ability: Even if there are slight ripples on the liquid surface or some reflections are obscured, the square corner points are still easy to identify.

[0048] Clear geometric characteristics: The four corner points of the square have clear geometric relationships in the image, which facilitates the algorithm's positioning and measurement.

[0049] High robustness: Compared to other feature points (such as edges and lines), square corner points are more tolerant of noise and interference.

[0050] In simple terms, "corner coordinates" refer to the specific positions of the four corner points of the square hollow structure 4011 in the reflection image. For example, assuming that the four corner points of a square reflection in the image are the coordinates of the upper left corner, the upper right corner, the lower left corner, and the lower right corner (a total of four coordinates), the system can calculate the shape and position changes of the reflection using these coordinates, and then deduce the changes in the liquid level height.

[0051] In single crystal furnace liquid level positioning, these corner coordinates act as "reference points," helping the system accurately measure the liquid level height and achieve automatic adjustment, thereby improving production efficiency and product quality.

[0052] (3) The “fixed crucible” mentioned above refers to the precise adjustment and positioning of crucible 2 (a container for holding molten silicon) during the single crystal furnace production process to ensure the consistency and stability of the liquid level height during single crystal growth. This is a key step in the single crystal manufacturing process.

[0053] In layman's terms, "setting the crucible" can be understood as "determining the position of crucible 2." Specifically, before or during single crystal pulling, the height of the molten silicon surface is measured, and the position of crucible 2 is adjusted as needed to maintain a suitable distance between the molten silicon surface and the crystal pulling head (i.e., the distance from the liquid outlet 101). This process directly affects the quality, growth rate, and consistency of the single crystal.

[0054] Why is a "fixed-pot" solution needed? 1. Ensure consistency of the distance between liquid outlets 101: The 101 gap refers to the distance between the surface of the molten silicon and the crystal pulling head. This distance is crucial to the speed and quality of single crystal growth. If the 101 gap is too large or too small, it will affect the crystal growth rate, shape, and defect density.

[0055] 2. Improve production efficiency: Precise "crate setting" can reduce manual intervention, improve automation, and thus speed up the production process.

[0056] 3. Reduce scrap rate: By accurately "fixing the crucible", crystal defects or breakage problems caused by inconsistent liquid level can be avoided.

[0057] The "crate setting" method in this solution achieves the "crate setting" process through the following steps: 1. Reflection acquisition of feature plate 401: A molybdenum feature plate 401 is installed on the outside of the guide tube 1, and its square hollow structure 4011 forms a stable reflection on the liquid surface.

[0058] The CCD camera captures the reflection image through the viewing window.

[0059] 2. Corner coordinate extraction: The image processing module extracts the coordinates of the square corner points in the reflection, which reflect the height information of the liquid surface.

[0060] 3. Calculate the change in liquid level: The actual change in liquid level height is calculated based on the reflection deformation ΔH.

[0061] 4. Automatically adjust the position of crucible 2: The calculation results are fed back to the lifting mechanism, which automatically adjusts the position of crucible 2 so that the liquid level reaches the set value.

[0062] In summary, "crate setting" is a crucial step in single crystal production to ensure consistent liquid level. This solution improves the accuracy and automation of the "crate setting" process by using a reflection feature recognition method, resolving issues such as liquid level fluctuations and recognition failures in traditional methods, thereby significantly improving the efficiency and quality of single crystal production.

[0063] Example 2 This embodiment provides a single crystal furnace liquid level positioning device based on reflection feature recognition. The difference from Embodiment 1 is that the hollow structure 4011 adopts a cross-shaped hole or a diamond-shaped hole, and the hollow ratio can be adjusted to adapt to different melt characteristic requirements.

[0064] Example 3 A single crystal furnace includes a crucible 2 and a flow guide cylinder 1 inside the furnace. A circular liquid inlet 101 is opened at the center of the bottom of the flow guide cylinder 1. The furnace also includes the liquid level positioning device of the single crystal furnace.

[0065] A liquid level positioning method for a single crystal furnace liquid level positioning device based on reflection feature recognition includes the following steps: A feature plate 401 with a square hollow structure 4011 is installed on the outside of the guide tube 1; The reflection of feature plate 401 is imaged onto the image processing module (such as a CCD camera) through the observation window. The coordinates of the square corner points in the reflection are extracted using the image processing module. Calculate the change in liquid level ΔH based on the reflection deformation; The calculation results are fed back to the lifting mechanism, which automatically adjusts the position of crucible 2.

[0066] The beneficial effects of the technical solution of this utility model are: This device utilizes the anti-interference characteristics of the corner points of the hollow structure 4011 on the feature plate 401 (resisting liquid surface shaking and silicon sputtering), increases the features of the furnace reflection image acquisition, reduces the blurring of feature points caused by liquid surface shaking, improves the success rate of the crucible setting process, ensures the consistency of the liquid outlet 101 distance, improves the reflection imaging capability, and enhances the robustness of image recognition.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

[0068] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A liquid level positioning device for a single crystal furnace based on reflection feature recognition, wherein the single crystal furnace has a crucible (2) and a guide tube (1), and a circular liquid inlet (101) is provided at the center of the bottom of the guide tube (1), characterized in that, include: Feature plate (401), which is horizontally installed on the outside of the guide tube (1), has a hollow structure (4011) for forming a stable reflection on the surface of the silicon liquid in the crucible (2); The image processing module is used to extract the coordinates of the corner points in the reflection and calculate the change in liquid level height ΔH based on the deformation of the reflection.

2. The liquid level positioning device for a single crystal furnace according to claim 1, characterized in that, The hollow structure (4011) uses rectangular holes.

3. The liquid level positioning device for a single crystal furnace according to claim 2, characterized in that, The hollow structure (4011) of the feature plate (401) is designed as a rectangular hole of 4mm×8mm to enhance reflection contrast and corner stability.

4. The liquid level positioning device for a single crystal furnace according to claim 1, characterized in that, It also includes a connecting structure, which includes an upper clamping plate (403) and an intermediate connecting plate (402). The upper clamping plate (403), the intermediate connecting plate (402) and the feature plate (401) are connected in sequence to form a C-shaped bending structure (4). The opening groove of the C-shaped bending structure (4) is correspondingly clamped to the edge of the liquid outlet (101). The upper clamping plate (403) is located at the upper edge of the liquid outlet (101), the intermediate connecting plate (402) is correspondingly attached to the inner wall of the liquid outlet (101), and the feature plate (401) is located at the lower edge of the liquid outlet (101).

5. The liquid level positioning device for a single crystal furnace according to claim 4, characterized in that, The upper edge of the liquid inlet (101) is provided with a support ring mounting groove (102) for mounting the support ring (3). The upper clamping plate (403) is in contact with the bottom wall of the support ring mounting groove (102). The upper clamping plate (403) is provided with a circular mounting hole (4031). The C-shaped bending structure (4) is connected to the guide tube (1) through the circular mounting hole (4031) to form a flange connection, which is used to ensure that the feature plate (401) and the liquid surface maintain a constant relative position.

6. The liquid level positioning device for a single crystal furnace according to claim 5, characterized in that, The circular mounting hole (4031) and the hollow structure (4011) are coupled to ensure a tight fit between the feature plate (401) and the guide tube (1).

7. The liquid level positioning device for a single crystal furnace according to claim 1, characterized in that, The feature plate (401) is made of molybdenum or molybdenum alloy.

8. The liquid level positioning device for a single crystal furnace according to claim 7, characterized in that, The feature plate (401) is made of forged molybdenum alloy with a surface roughness of Ra0.8μm.

9. The liquid level positioning device for a single crystal furnace according to claim 1, characterized in that, The hollow structure (4011) adopts cross-shaped holes or diamond-shaped holes, and the hollow ratio can be adjusted to meet the different melt characteristics requirements.

10. A single crystal furnace, characterized in that, Includes the liquid level positioning device for a single crystal furnace as described in any one of claims 1-9.

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