Thermal insulation cylinder applied to thermal field of single crystal furnace and single crystal furnace

Abstract

The utility model discloses a thermal insulation cylinder applied to a single crystal furnace thermal field and a single crystal furnace. The heat preservation cylinder can comprise a heat preservation cylinder body and a heat reflecting layer, and the heat reflecting layer is arranged on the inner side wall of the heat preservation cylinder body. The heat reflecting layer comprises a plurality of rows of heat reflecting structures, each row of heat reflecting structures comprises bulge structures and groove structures which are alternately and tightly arranged, or each row of heat reflecting structures comprises groove structures which are tightly arranged; for multiple rows of heat reflection structures comprising convex structures and groove structures, the convex structures and the groove structures in every two adjacent rows of heat reflection structures are arranged in a staggered mode in the alternate arrangement direction. The thermal insulation cylinder can reflect heat, improve the growth environment of monocrystalline silicon, and reduce the electric energy consumption of the monocrystalline silicon Czochralski process, thereby achieving the purpose of reducing the production cost of monocrystalline silicon.

Description

Technical Field

[0001] The utility model relates to a heat preservation tube applied to a single crystal furnace thermal field and a single crystal furnace. Background Art

[0002] In the Czochralski silicon single crystal process, high-purity polycrystalline silicon contained in a quartz crucible is heated primarily by a high-frequency coil or current heater to melt the polycrystalline silicon. A seed crystal is then brought into contact with the molten silicon. At the appropriate temperature, at the solid-liquid interface, the seed crystal forms a regular crystal with a known crystal orientation, transforming into a single crystal. Throughout the single crystal growth process, electrical energy is continuously consumed to heat the silicon solution and the single crystal furnace to maintain the transformation of the silicon solution into a single crystal. The thermal insulation performance of the single crystal furnace's insulation barrel not only affects single crystal silicon growth but also its production cost (good insulation results in low energy consumption, while poor insulation results in high energy consumption). Therefore, by modifying the existing single crystal furnace's thermal field insulation barrel structure, single crystal silicon growth can be improved and production costs reduced. Utility Model Content

[0003] In view of this, the utility model provides an insulation tube and a single crystal furnace applied to the thermal field of a single crystal furnace. The insulation tube can reflect heat, improve the growth environment of single crystal silicon, and reduce the power consumption of the direct-pull single crystal process, thereby achieving the purpose of reducing the production cost of single crystal silicon.

[0004] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0005] In a first aspect, an embodiment of the present invention provides a heat preservation cylinder for use in a single crystal furnace thermal field, comprising: a heat preservation cylinder body and a heat reflection layer, wherein:

[0006] The heat reflecting layer is arranged on the inner side wall of the heat preservation cylinder body;

[0007] The heat reflecting layer includes multiple rows of heat reflecting structures, wherein each row of the heat reflecting structures includes alternately and closely arranged convex structures and concave structures, or each row of the heat reflecting structures includes closely arranged concave structures;

[0008] With respect to the multiple rows of heat reflecting structures including the protruding structures and the groove structures, the protruding structures and the groove structures in every two adjacent rows of the heat reflecting structures are staggered in the alternating arrangement direction.

[0009] In a second aspect, an embodiment of the present invention provides a single crystal furnace, comprising: a heat preservation cylinder applied to the thermal field of a single crystal furnace provided in the embodiment of the first aspect mentioned above.

[0010] The technical solution of the first aspect of the above utility model has the following advantages or beneficial effects:

[0011] The insulation cylinder provided in the embodiment of the present invention is provided with a heat reflecting layer, which includes multiple rows of heat reflecting structures. Each row of heat reflecting structures is designed to include alternating and closely arranged protrusion structures and groove structures, and the protrusion structures and groove structures in each two adjacent rows of heat reflecting structures are staggered in the alternating arrangement direction. By coordinating the protrusion structures and groove structures with the staggered arrangement of each two adjacent rows of heat reflecting structures, the heat in the thermal field of the single crystal furnace can be reflected to the crucible area, so as to better regulate the heat of the silicon solution and reduce the energy required to heat the silicon solution. While improving the single crystal silicon growth environment, it can reduce the power consumption of the direct-pull single crystal process, thereby achieving the purpose of reducing the production cost of single crystal silicon.

[0012] In addition, each row of heat reflection structures included in the heat reflection layer of the insulation tube provided by the present invention can also be a closely arranged groove structure. Through the surface of the groove structure, it can also realize the reflection of heat in the thermal field of the single crystal furnace to the crucible area, so as to better regulate the heat of the silicon solution and reduce the energy required to heat the silicon solution. While improving the single crystal silicon growth environment, it can reduce the power consumption of the direct pulling single crystal process, thereby achieving the purpose of reducing the production cost of single crystal silicon. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic cross-sectional view of the circumferential structure of a heat preservation cylinder applied to the thermal field of a single crystal furnace according to an embodiment of the present utility model;

[0014] Figure 2 This is a schematic diagram of a radial structural cross-section of a heat preservation cylinder applied to a single crystal furnace thermal field according to an embodiment of the present utility model;

[0015] Figure 3A This is a three-dimensional schematic diagram of the partial structure of the first heat reflection layer in the heat preservation cylinder applied to the thermal field of a single crystal furnace provided in an embodiment of the utility model;

[0016] Figure 3B This is a schematic perspective view of the partial structure of a second heat reflection layer in a heat preservation cylinder applied to a single crystal furnace thermal field according to an embodiment of the present utility model;

[0017] Figure 4 This is a three-dimensional structural diagram of the relative positional relationship between the groove structure and the protrusion structure in the heat reflection layer provided by an embodiment of the present utility model;

[0018] Figure 5 This is a schematic diagram of a first relative position relationship between a crucible and a heat reflecting layer in a single crystal furnace provided according to an embodiment of the present utility model;

[0019] Figure 6This is a schematic diagram of a second relative position relationship between the crucible and the heat reflecting layer in the single crystal furnace provided by an embodiment of the present utility model;

[0020] Figure 7 This is a schematic diagram of the third relative position relationship between the crucible and the heat reflecting layer in the single crystal furnace provided according to an embodiment of the present utility model.

[0021] The reference numerals are as follows:

[0022] 10 - insulation tube body; 20 - heat reflecting layer; 21 - raised structure; 211 - side of raised structure; 22 - groove structure; 221 - triangular side of groove structure; 30 - insulation felt layer; 40 - furnace body; 50 - crucible; 60 - crucible rod. DETAILED DESCRIPTION

[0023] Czochralski (CZ) pulling is currently the most widely used technology for producing single crystal silicon. The CZ pulling process primarily involves loading high-purity polycrystalline silicon into a quartz crucible. A surrounding coil or current heater, loaded with high-frequency waves, heats the crucible, melting the polycrystalline silicon. A single silicon crystal (called a seed crystal) with a specific crystal orientation is then placed in contact with the molten silicon solution in the crucible. At the appropriate temperature, the silicon crystals will form a regular pattern at the solid-liquid interface, following the arrangement of silicon atoms on the seed crystal, ultimately becoming a single crystal. During this crystallization process, the seed crystal is lifted upward. When the seed crystal grows to a diameter close to the target, the lifting speed is adjusted to maintain the uniform diameter of the single crystal. This process continues until most of the silicon solution has crystallized into a silicon ingot, leaving only a small amount of material. By adjusting the lifting speed and solution temperature, the crystal diameter is gradually reduced, forming a tail-shaped cone. When the cone tip is sufficiently small, the crystal separates from the melt, completing the entire silicon single crystal growth process.

[0024] The above description of the Czochralski process shows that the entire crystal growth process requires the continuous consumption of electrical energy, which is converted into heat energy to maintain the transformation of silicon liquid into single crystals. On the one hand, problems with temperature control can lead to quality issues in the pulled single crystal silicon rods. Therefore, it is necessary to ensure that the temperature of the thermal field in the Czochralski single crystal is maintained within a relatively stable temperature range. One way to maintain this stable temperature range is to ensure that the thermal field has relatively high thermal insulation properties. On the other hand, the amount of electrical energy consumed to provide heat is a significant factor affecting production costs, especially in today's single crystal production costs, which directly affect the profits of the photovoltaic industry. Therefore, solving the problems of thermal insulation and high energy consumption of the thermal field is one of the main means to reduce the energy consumption and cost of single crystal production.

[0025] In order to solve the energy consumption and single crystal production costs of Czochralski single crystals, the utility model provides a heat preservation tube and a single crystal furnace applied to the thermal field of a single crystal furnace.

[0026] The specific structure of the heat preservation cylinder and the single crystal furnace provided by the embodiment of the present invention and applied to the thermal field of the single crystal furnace will be described in detail below.

[0027] in, Figure 1 This is a schematic cross-sectional view of the circumferential structure of a heat preservation cylinder applied to the thermal field of a single crystal furnace according to an embodiment of the present utility model; Figure 2 This is a schematic diagram of a radial structural cross-section of a heat preservation cylinder applied to a single crystal furnace thermal field according to an embodiment of the present utility model; Figure 3A This is a partial structural perspective diagram of a first type of heat reflection layer in a heat preservation cylinder applied to a single crystal furnace thermal field according to an embodiment of the present utility model; Figure 3B This is a partial structural perspective diagram of a second heat reflection layer in a heat preservation cylinder applied to a single crystal furnace thermal field according to an embodiment of the present utility model; Figure 4 This is a three-dimensional structural diagram of the relative positional relationship between the groove structure and the protrusion structure in the heat reflection layer provided in an embodiment of the present utility model; Figures 5 to 7 It is a schematic diagram of various relative position relationships between the crucible and the heat reflecting layer in the single crystal furnace according to an embodiment of the present utility model.

[0028] Specifically, if Figure 1 and Figure 2 As shown, the heat preservation cylinder provided by the embodiment of the present invention for use in the thermal field of a single crystal furnace may include: a heat preservation cylinder body 10 and a heat reflecting layer 20 .

[0029] Among them, such as Figure 1 As shown, the heat-reflecting layer 20 is generally provided on the inner sidewall of the heat-insulating tube body 10. The heat-reflecting layer 20 can be formed by pressing the inner sidewall of the heat-insulating tube body 10 with a mold having specific three-dimensional patterns, or by combining masking and deposition, wherein the mask shape is designed according to the heat-reflecting layer 20. In addition, the heat-reflecting layer 20 can also be obtained by combining mold pressing and masking and deposition. Specifically, the mold presses out a groove structure 22, and the masking and deposition combine to form a protruding structure 21. Furthermore, the heat-reflecting layer 20 can be formed of heat-insulating carbon materials, molybdenum materials, tungsten materials, niobium materials, and other alloy materials.

[0030] Specifically, if Figure 1 、 Figure 3A and Figure 3B As shown, the heat reflecting layer 20 includes multiple rows of heat reflecting structures. Specifically, the heat reflecting structures can have two structures.

[0031] Among them, the first structure of the heat reflection structure is: Figure 3AAs shown, each row of heat reflecting structures includes protrusion structures 21 and groove structures 22 arranged alternately and closely; the protrusion structures 21 and groove structures 22 in each adjacent row of heat reflecting structures are staggered in the alternating arrangement direction. Figure 1 The circumferential direction D1 is arranged, and accordingly, multiple rows of heat reflecting structures are arranged in the radial direction of the heat preservation tube. In addition, each row of heat reflecting structures can be arranged along Figure 2 The radial direction D2 is arranged accordingly, and multiple rows of heat reflecting structures are arranged circumferentially of the heat insulation tube. By arranging the heat reflecting structures circumferentially or radially, the arrangement of the protrusion structure 21 and the groove structure 22 can be facilitated.

[0032] The groove structure 22 and the protrusion structure 21 are an integrated structure. This integrated structure can make the heat reflection layer 20 reflect heat and the heat reflection direction more stable, so that the heat reflection layer 20 has a relatively long service life.

[0033] The second structure of heat reflective structure: Figure 3B As shown, each row of heat reflecting structures includes closely arranged groove structures 22. Heat is reflected by each side of the groove structure 22, so that the reflected heat reaches the crucible area.

[0034] Furthermore, for the above-mentioned heat reflection structure, whether it is the first structure or the second structure, the heat preservation tube body 10 and the heat reflection layer 20 are an integrated structure, which can further improve the service life of the heat reflection layer 20.

[0035] For the first structure of the above-mentioned heat reflection structure, the heat reflection layer 20 set by the insulation tube includes multiple rows of heat reflection structures. Each row of heat reflection structures is designed to include alternating and closely arranged protrusion structures 21 and groove structures 22, and the protrusion structures 21 and groove structures 22 in each two adjacent rows of heat reflection structures are staggered in the alternating arrangement direction. By coordinating the staggered arrangement of the protrusion structures 21 and groove structures 22 with each two adjacent rows of heat reflection structures, the heat in the thermal field of the single crystal furnace can be reflected to the crucible area, so as to better regulate the heat of the silicon solution and reduce the energy required to heat the silicon solution. While improving the single crystal silicon growth environment, it can reduce the power consumption of the direct-pull single crystal process, thereby achieving the purpose of reducing the production cost of single crystal silicon.

[0036] For the second structure of the above-mentioned heat reflection structure, each row of heat reflection structures included in the heat reflection layer set in the insulation tube can also be a closely arranged groove structure. Through the surface of the groove structure, it can also realize the reflection of heat in the thermal field of the single crystal furnace to the crucible area, so as to better regulate the heat of the silicon solution and reduce the energy required to heat the silicon solution. While improving the single crystal silicon growth environment, it can reduce the power consumption of the direct pulling single crystal process, thereby achieving the purpose of reducing the production cost of single crystal silicon.

[0037] In addition, the heat preservation tube provided by the embodiment of the present invention achieves the purpose of reducing heat energy consumption by changing the internal structure of the single crystal furnace thermal system. Figure 3A and Figure 4 As shown, in each adjacent two rows of heat reflecting structures, the groove structure 22 in one row of heat reflecting structures corresponds to the protruding structure 21 in the other row of heat reflecting structures. The side of the groove structure 22 can be extended by setting the structure corresponding to the groove, thereby improving the heat reflecting ability of the heat reflecting structure so as to control the direction of heat reflection.

[0038] More preferably, for the first structure of the above heat reflection structure, as Figure 3A and Figure 4 As shown, the raised structure 21 is a tetrahedron structure, one side of which is attached to the inner side wall of the heat preservation tube body 10 or is an integral structure with the inner side wall of the heat preservation tube body 10; the groove structure 22 is surrounded by three triangular side surfaces; for each triangular side surface of the groove structure 22, the triangular side surface is adjacent to the side surface of the adjacent raised structure 21. Specifically, for the tetrahedron structure, as shown in FIG. Figure 4 For example, part of the heat collides with the lower side surface A of the groove structure 22 or the side surface of the protruding structure 21 which is an integral structure with the lower side surface A. The heat that collides with the lower side surface A or the side surface of the protruding structure 21 which is an integral structure with the lower side surface A is reflected to the right side surface B of the groove structure 22 or the side surface of the protruding structure 21 which is an integral structure with the right side surface B (abbreviated as side surface A->side surface B); and is reflected from the right side surface B or the side surface of the protruding structure 21 which is an integral structure with the right side surface B to the left side surface C of the groove structure 22 or the side surface of the protruding structure 21 which is an integral structure with the left side surface C (side surface B->side surface C), and is reflected from the left side surface C or the side surface of the protruding structure 21 which is an integral structure with the left side surface C back into the single crystal furnace or the crucible (side surface C->furnace / crucible). It can be understood that Figure 4The heat reflection path given is only an example. The heat reflection path can also be side A->side C->side B->furnace / crucible, or side C->side A->side B->furnace / crucible, side C->side B->side A->furnace / crucible, side B->side C->side A->furnace / crucible, etc., that is, heat can be reflected into the furnace or crucible from all angles, thereby improving the heat reflection ability of the heat reflection structure so that the heat reflection direction can be controlled.

[0039] In addition, through the multiple rows of heat reflection structures, each row of heat reflection structures is designed to include alternating and closely arranged protrusion structures 21 and groove structures 22, and the protrusion structures 21 and groove structures 22 in each two adjacent rows of heat reflection structures are staggered in the alternating arrangement direction, and are coordinated with the protrusion structure 21 as a tetrahedral structure, which increases the heat reflection area of ​​the insulation tube and heat, and can reflect heat radiation back to the inside, thereby improving the heat reflection effect of the inner wall of the insulation tube. The reflected heat can be reused, which improves the heat utilization rate and effectively reduces heat loss, thereby increasing the insulation effect of the insulation tube, reducing power consumption, being highly practical, and reducing production costs. Moreover, the insulation tube provided by the embodiment of the utility model has a simple structure and is highly practical.

[0040] For each side surface of the groove structure 22, the side surface and the side surface of the adjacent protrusion structure 21 form a plane or an arc surface. Figure 3A and Figure 4 In addition, the side surfaces of the groove structure 22 and the side surfaces of the adjacent protrusion structure 21 may also form a certain angle. Users can design the relationship between the side surfaces of the groove structure 22 and the side surfaces of the adjacent protrusion structure 21 as needed to increase the flexibility of the design of the heat reflective layer 20.

[0041] Furthermore, if Figure 3B As shown, for the heat reflection structure including closely arranged groove structures 22 , the groove structure 22 is surrounded by three triangular side surfaces 221 .

[0042] More preferably, for the above heat reflection structure, whether it is the first structure or the second structure, the angle between each two adjacent side surfaces in the groove structure 22 is greater than 0° and less than 180°. Figure 4As shown, the angle between each two adjacent side surfaces refers to the angle between side A and side B, the angle between side B and side C, and the angle between side C and side A. For example, the angle can be 5°, 10°, 30°, 45°, 60°, 70°, 85°, 90°, 100°, 110°, 120°, 130°, 145°, 160°, or 175°. Preferably, the angle between each two adjacent side surfaces is 60°. The adjustable angle between the side surfaces can adjust the heat reflection area according to demand. According to the drawing requirements, the radiated heat can be focused on a smaller area for utilization, thereby improving the heat utilization rate.

[0043] More preferably, for the above-mentioned heat reflection structure, whether it is the first structure or the second structure, the three triangular side surfaces of the groove structure 22 intersect at one point to facilitate structural design, make the structure production simpler, and effectively improve the production efficiency of the heat reflection layer 20.

[0044] Furthermore, the heat reflecting layer 20 corresponds to the crucible arrangement in the thermal field of the single crystal furnace. Figure 5 In the structure shown in FIG. 1 , the heat reflecting layer 20 corresponds to the upper half of the crucible and a portion exceeding the upper edge of the crucible. In addition, the position of the heat reflecting layer 20 can also be as shown in FIG. Figure 6 In the structure shown in FIG. 1 , the heat reflecting layer 20 extends from a portion exceeding the upper edge of the crucible to a portion of the lower edge of the crucible (i.e., the heat reflecting layer 20 completely covers the side area of ​​the crucible). In addition, the position of the heat reflecting layer 20 can also be as shown in FIG. Figure 7 In the structure shown, the heat reflecting layer 20 corresponds to the lower half of the crucible and a portion exceeding the lower edge of the crucible. By designing different positions of the heat reflecting layer 20, the design of the heat reflecting position can be better met, and the requirements of single crystal pulling can be better met.

[0045] Furthermore, if Figure 1 and Figure 2 As shown, the insulation cylinder for use in the thermal field of a single crystal furnace provided in the above embodiment may further include an insulation felt layer 30 in contact with the outer wall of the insulation cylinder body 10. The design of this insulation felt layer 30 further enhances the thermal insulation performance of the insulation cylinder. Alternatively, aerogel may be used in place of the insulation felt layer 30. By replacing the insulation felt layer 30 with aerogel, which has a lower applicable temperature but excellent thermal insulation properties, the overall thermal insulation performance of the thermal field is further enhanced, ultimately reducing power consumption and production costs.

[0046] Furthermore, the present invention also provides a single crystal furnace, which may include: the heat preservation cylinder provided in the above embodiment and applied to the thermal field of the single crystal furnace.

[0047] Specifically, if Figures 5 to 7As shown, the single crystal furnace provided by the present invention may include: a furnace body 40, a crucible 50 and a crucible rod 60. It is worth noting that, Figures 5 to 7 The partial structure of the single crystal furnace is given as an example only. In addition to the heat preservation tube, the furnace body 40, the crucible 50 and the crucible rod 60, the single crystal furnace may also include a tray, a water-cooled heat shield, a heat preservation pipeline, a heater, etc.

[0048] from Figures 5 to 7 It can be seen that in the single crystal furnace, the heat reflecting layer 20 in the heat preservation tube is arranged corresponding to the crucible 50. Specifically, Figure 5 In the structure shown in FIG. 1 , the heat reflecting layer 20 corresponds to the upper half of the crucible and a portion exceeding the upper edge of the crucible. In addition, the position of the heat reflecting layer 20 can also be as shown in FIG. Figure 6 In the structure shown in FIG. 1 , the heat reflecting layer 20 extends from a portion exceeding the upper edge of the crucible to a portion of the lower edge of the crucible (i.e., the heat reflecting layer 20 completely covers the side area of ​​the crucible). In addition, the position of the heat reflecting layer 20 can also be as shown in FIG. Figure 7 In the structure shown, the heat reflecting layer 20 corresponds to the lower half of the crucible and a portion exceeding the lower edge of the crucible. By designing different positions of the heat reflecting layer 20, the design of the heat reflecting position can be better met, and the requirements of single crystal pulling can be better met.

[0049] The single crystal furnace provided by the embodiment of the present invention designs a heat reflecting layer 20 corresponding to the crucible, so that heat can pass through the alternating and closely arranged protrusion structures and groove structures included in the heat reflecting layer, and the protrusion structures and groove structures in each two adjacent rows of heat reflecting structures are staggered in the alternating arrangement direction. By coordinating the protrusion structures and groove structures with the staggered arrangement of each two adjacent rows of heat reflecting structures, the heat in the thermal field of the single crystal furnace can be reflected to the crucible area, so as to better regulate the heat of the silicon solution and reduce the energy required to heat the silicon solution. While improving the single crystal silicon growth environment, it can reduce the power consumption of the CZ single crystal process, thereby achieving the purpose of reducing the production cost of single crystal silicon.

[0050] The above steps are merely provided to help understand the method, structure, and core concept of the present invention. A person skilled in the art would be able to make improvements and modifications to the present invention without departing from the principles of the present invention, and such improvements and modifications would also fall within the scope of protection of the claims of the present invention.

Claims

1. A heat preservation cylinder used in the thermal field of a single crystal furnace, characterized in that: include: The heat-insulating cylinder body (10) and the heat-reflecting layer (20) are provided, wherein: The heat reflecting layer (20) is arranged on the inner side wall of the heat-insulating cylinder body (10); The heat reflecting layer (20) comprises a plurality of rows of heat reflecting structures, wherein each row of the heat reflecting structures comprises alternately and closely arranged protrusion structures (21) and groove structures (22), or each row of the heat reflecting structures comprises closely arranged groove structures (22); For multiple rows of heat reflection structures comprising the protruding structures (21) and the groove structures (22), the protruding structures (21) and the groove structures (22) in every two adjacent rows of the heat reflection structures are staggered in an alternating arrangement direction.

2. The heat preservation cylinder used in the thermal field of a single crystal furnace according to claim 1, characterized in that: For multiple rows of heat reflecting structures including the protruding structures (21) and the groove structures (22), in each two adjacent rows of the heat reflecting structures, the groove structures (22) in one row of the heat reflecting structures correspond to the protruding structures (21) in the other row of the heat reflecting structures.

3. The heat preservation cylinder used in the thermal field of a single crystal furnace according to claim 1 or 2, characterized in that: With respect to the multi-row heat reflection structure comprising the protruding structure (21) and the groove structure (22), the protruding structure (21) is a tetrahedron structure, and one side surface of the tetrahedron structure is attached to the inner side wall of the heat-insulating tube body (10) or forms an integral structure with the inner side wall of the heat-insulating tube body (10); The groove structure (22) is surrounded by three triangular side surfaces (221); For each triangular side surface (221) of the groove structure (22), the triangular side surface (221) is adjacent to the side surface (211) of the adjacent protrusion structure (21); or, A heat reflecting structure comprising closely arranged groove structures (22), wherein the groove structures (22) are surrounded by three triangular side surfaces (221).

4. The heat preservation cylinder used in the thermal field of a single crystal furnace according to claim 3, characterized in that: For the multi-row heat reflection structure including the protrusion structure (21) and the groove structure (22), For each of the triangular side surfaces (221) of the groove structure (22), the triangular side surface and the side surface (211) of the adjacent protrusion structure (21) form a plane or an arc surface.

5. The heat preservation cylinder used in the thermal field of a single crystal furnace according to claim 3, characterized in that: The included angle between each two adjacent triangular side faces (221) in the groove structure (22) is greater than 0° and less than 180°.

6. The heat preservation cylinder used in the thermal field of a single crystal furnace according to claim 3, characterized in that: The three triangular side faces (221) of the groove structure (22) meet at one point.

7. The heat preservation cylinder used in the thermal field of a single crystal furnace according to any one of claims 1, 2, and 4 to 6, characterized in that: The heat-insulating cylinder body (10) and the heat-reflecting layer (20) are an integrated structure; and / or, With respect to the multi-row heat reflection structure comprising the protrusion structure (21) and the groove structure (22), the groove structure (22) and the protrusion structure (21) are an integrated structure; With respect to a heat reflection structure comprising closely arranged groove structures (22), each of the groove structures (22) is an integral structure.

8. The heat preservation cylinder used in the thermal field of a single crystal furnace according to any one of claims 1, 2, and 4 to 6, characterized in that: The heat reflection layer (20) is arranged corresponding to the crucible in the thermal field of the single crystal furnace.

9. The heat preservation cylinder used in the thermal field of a single crystal furnace according to any one of claims 1, 2, and 4 to 6, characterized in that: Also includes: A thermal insulation felt layer (30) is in contact with the outer side wall of the thermal insulation cylinder body (10).

10. A single crystal furnace, characterized in that: include: The heat preservation cylinder used in the thermal field of a single crystal furnace as described in any one of claims 1 to 9.

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