Backflow prevention device for crucible in electron beam evaporation coating

Abstract

The backflow prevention device comprises a crucible body, a groove with an upward opening is formed in the center of the top of the crucible body, a crucible sleeve is arranged in the groove, the top face of the crucible body is a special-shaped face, the special-shaped face comprises a horizontal plane vertically flush with the top of the crucible sleeve, and the horizontal plane is provided with a horizontal plane. The front end and the rear end of the horizontal plane extend outwards and upwards to form the first inclined faces or the first arc-shaped faces, the first inclined faces or the first arc-shaped faces are spaced from the edge of the top opening of the crucible sleeve, the first inclined faces or the first arc-shaped faces are spaced from the top of the crucible sleeve, and the first inclined faces or the first arc-shaped faces have a certain buffering effect. The liquid film material cannot flow back into the crucible sleeve immediately to pollute the film material in the crucible sleeve, the crucible sleeve cannot crack due to temperature difference, the film material cannot flow back when the whole process is finished, the service life of the crucible body and the crucible sleeve is prolonged, and meanwhile, the evaporation coating effect is better.

Description

Technical Field

[0001] The present invention belongs to the technical field of vacuum evaporation coating machines, and more specifically, relates to an anti-backflow device for a crucible in electron beam evaporation coating. Background Art

[0002] A vacuum evaporation coating machine is a device that, under vacuum conditions, evaporates a coating material (or film material) by means of current heating, electron beam bombardment heating, ion source bombardment, etc., vaporizes it, and then makes the vaporized particles fly to the surface of a substrate and condense to finally form a thin film. Vacuum evaporation coating has the advantages of simple film-forming method, high purity and density of the thin film, and unique film structure and properties, so it has been widely used.

[0003] Electron beam evaporation is a type of physical vapor deposition. Different from traditional evaporation coating methods, electron beam evaporation can precisely use high-energy electrons to bombard the coating material in the crucible through the cooperation of electromagnetic fields, melt and vaporize it, and then deposit it on the substrate. During the process of electron beam heating the film material to evaporate it, while the film material forms a film on the product, it also forms a film on the nearest chamber wall. Long-term operation causes dust accumulation on the inner wall of the furnace body. Since the continuously circulating evaporated and sputtered atoms have a certain amount of energy, they can secondarily impact the film layer formed on the chamber wall. The film layer on the chamber wall forms dust and dirt due to excessive deposition times of the coating, and then also deposits on the coating substrate, resulting in dirt or dust spots in the film layer of the product to be coated, directly affecting the product quality due to this secondary sputtering of atoms.

[0004] However, in the prior art, when evaporating and coating the film material, when adding the film material into the crucible, inevitably a small amount of the film material will adhere to the top surface of the crucible, and when the electron beam is depositing and coating, there will be evaporation and sputtering, and a small amount of the film material will adhere to the inner wall of the crucible chamber. When performing electron beam evaporation coating, the electron beam will be refracted secondarily. Due to the high temperature, the film material adhering to the inner wall of the crucible chamber and the top surface of the crucible will be evaporated and coated, which will form a flow of liquid film material and finally flow into the crucible, not only polluting the film material, but also possibly causing the crucible to crack due to temperature difference, affecting the coating efficiency, process requirements and quality. Summary of the Invention

[0005] Therefore, to solve the above technical problems, the present invention provides an anti-backflow device for a crucible in electron beam evaporation coating, which includes a crucible body 10. At the center of the top of the crucible body 10, there is a groove 50 with an upward opening. A crucible sleeve 60 is placed in the groove 50. The top surface of the crucible body 10 is a special-shaped surface, which includes a horizontal plane 200 that is vertically flush with the top of the crucible sleeve 60. At both the front and rear ends of the horizontal plane 200, they extend outward and upward to form a first inclined plane 210 or a first arc surface 220. There is a gap between the first inclined plane 210 or the first arc surface 220 and the edge of the top opening of the crucible sleeve 60. When evaporating and coating the film material, the film material is added into the crucible sleeve 60. Inevitably, a small amount of the film material will adhere to the top surface of the crucible body 10. The electron beam enters the crucible sleeve 60 through the electron beam channel cavity for evaporation coating. At the same time, the electron beam will be refracted and sputtered onto the top surface of the crucible body 10 in the crucible sleeve 60 to form a secondary electron beam. At this time, the secondary electron beam will evaporate and coat the film material adhering to the top surface of the crucible body 10, forming a liquid that flows downward. Since there is a gap between the first inclined plane 210 or the first arc surface 220 and the top of the crucible sleeve 60, and the first inclined plane 210 or the first arc surface 220 has a certain buffering effect, the liquid film material will not immediately flow back into the crucible sleeve 60 to contaminate the film material in the crucible sleeve 60, nor will the crucible sleeve 60 crack due to the temperature difference. It will not flow back at the end of the entire process, improving the efficiency of evaporation coating, and also increasing the service life of the crucible body 10 and the crucible sleeve 60. At the same time, the effect of evaporation coating is better.

[0006] An anti-backflow device for a crucible in electron beam evaporation coating, which includes a crucible body 10. At the center of the top of the crucible body 10, there is a groove 50 with an upward opening. A crucible sleeve 60 is placed in the groove 50. The top surface of the crucible body 10 is a special-shaped surface, which includes a horizontal plane 200 that is vertically flush with the top of the crucible sleeve 60. At both the front and rear ends of the horizontal plane 200, they extend outward and upward to form a first inclined plane 210 or a first arc surface 220. There is a gap between the first inclined plane 210 or the first arc surface 220 and the edge of the top opening of the crucible sleeve 60.

[0007] Furthermore, an anti-adhesion plate assembly 90 adapted to its shape is connected to the upper part of the special-shaped surface. The anti-adhesion plate assembly 90 is in contact and fits with the top end of the crucible body 10. By setting the anti-adhesion plate assembly 90, it is convenient to replace the anti-adhesion plate assembly 90 after one process is completed, which will not affect the subsequent evaporation coating of the film material and improve the effect of evaporation coating.

[0008] Furthermore, the surface of the anti-spattering plate assembly 90 is provided with a nano-groove array to assist in blocking the backflow of the film material in the liquid state.

[0009] Furthermore, the depth and inclination angle of the nano-grooves satisfy the relational expression: d = 0.2θ - 25 (where d is the groove depth / nm and θ is the inclination angle / °).

[0010] Furthermore, the anti-spattering plate assembly 90 includes a first anti-spattering plate 901, a second anti-spattering plate 902, a third anti-spattering plate 903, and a fourth anti-spattering plate 904. One end of the first anti-spattering plate 901 is connected to the second anti-spattering plate 902, and both sides of the other end of the first anti-spattering plate 901 are connected to the third anti-spattering plate 903 and the fourth anti-spattering plate 904. There is a gap between the second anti-spattering plate 902, the third anti-spattering plate 903, the fourth anti-spattering plate 904 and the top edge of the crucible sleeve 60. And the sides of the third anti-spattering plate 903 and the fourth anti-spattering plate 904 close to the top of the crucible sleeve 60 are inclined second arc surfaces 100, and the side of the second anti-spattering plate 902 close to the groove 50 is an inclined second inclined surface 110.

[0011] Furthermore, the first anti-spattering plate 901, the second anti-spattering plate 902, the third anti-spattering plate 903, and the fourth anti-spattering plate 904 are integrally formed, and their surfaces are all coated with a high-temperature resistant coating, significantly improving the anti-adhesion and corrosion resistance.

[0012] Furthermore, the high-temperature resistant coating is a boron nitride composite coating.

[0013] Furthermore, the inclination angle of the inclined second arc surface 100 of the third anti-spattering plate 903 and the fourth anti-spattering plate 904 is 135 degrees.

[0014] Furthermore, the inclination angle of the second inclined surface 110 of the second anti-spattering plate 902 is 130 - 140 degrees, and this angle forms a 45° reflection angle with the electron beam incident direction (usually vertical or nearly vertical), so that the bombardment area of the secondary electron beam (generated by refraction) moves outside to the edge of the anti-spattering plate, avoiding interference with the main film material in the crucible sleeve. When the angle of the second inclined surface 110 > 130°, the Reynolds number (Re) drops from the turbulent flow region (Re > 4000) to the transitional flow region (2000 < Re < 4000), reducing the liquid film splash; when the angle < 140°, it avoids the liquid droplet impact and rebound due to the second inclined surface 110 being too steep.

[0015] Furthermore, a cooling and heat dissipation system is provided on the back of the anti-spattering plate assembly 90, increasing the heat dissipation efficiency by 40% and used to assist in slowing down the backflow of the film material.

[0016] Further, it further includes a bottom plate 20, a first coil 30 and a second coil 40. The top of the bottom plate 20 is connected to the crucible body 10. On both sides of the top of the front end of the crucible body 10, connecting blocks 70 are connected and arranged. There is a spacing between the two connecting blocks 70 to form the electron beam channel cavity. The first coils 30 are connected and arranged on both sides of the front end of the crucible body 10. Each first coil 30 is connected to its corresponding connecting block 70. The second coil 40 is arranged at the rear end of the crucible body 10. The bottom end of the second coil 40 is connected to the bottom plate 20. Magnetic conduction sheets 80 are connected and arranged on both sides of the second coil 40. The connecting block 70 and the crucible body 10 are integrally formed. One side of the connecting block 70 close to the top edge of the crucible sleeve 60 is the first arc surface 220.

[0017] Further, a card slot 120 with an opening facing outwards is arranged on one side of the connecting block 70. A fixed shaft 130 is arranged between the first coil 30 and the connecting block 70. One end of the fixed shaft 130 passes through the first coil 30 and is clamped with the card slot 120. A pressing plate 140 is connected to the other end of the fixed shaft 130. The pressing plate 140 is used to fix the first coil 30 to prevent sliding displacement.

[0018] Further, a magnetic conduction adapter plate 150 is arranged in the card slot 120. The magnetic conduction adapter plate 150 is sleeved with the fixed shaft 130. The magnetic conduction adapter plate 150 is used to guide and concentrate magnetic lines of force.

[0019] Further, a terminal protection cover 160 is connected to the lower part of the first coil 30 to prevent the first coil 30 from being invaded by external dust, moisture, foreign objects, etc., ensure normal operation, and avoid the occurrence of circuit obstacles and accidents.

[0020] Further, a protection plate 170 is arranged around the crucible body 10. The bottom end of the protection plate 170 is connected to the bottom plate 20. The protection plate 170 is used to block external dust, moisture, and foreign objects.

[0021] Further, a support plate 180 is connected to the bottom end of the bottom plate 20. Support columns 190 are connected and arranged at the four corners of the bottom end of the support plate 180.

[0022] Advantages of the present invention: The present invention provides an anti-backflow device for a crucible in electron beam evaporation coating, including a crucible body 10. At the center of the top of the crucible body 10, there is a groove 50 with an upward opening. A crucible sleeve 60 is placed in the groove 50. The top surface of the crucible body 10 is a special-shaped surface, which includes a horizontal plane 200 that is vertically flush with the top of the crucible sleeve 60. At both the front and rear ends of the horizontal plane 200, they extend outward and upward to form a first inclined plane 210 or a first arc surface 220. There is a gap between the first inclined plane 210 or the first arc surface 220 and the top edge of the crucible sleeve 60. When evaporating and coating the film material, the film material is added into the crucible sleeve 60. Inevitably, a small amount of the film material will adhere to the top surface of the crucible body 10. The electron beam enters the crucible sleeve 60 through the electron beam channel cavity for evaporation coating. At the same time, the electron beam will refract and splash onto the top surface of the crucible body 10 in the crucible sleeve 60 to form a secondary electron beam. At this time, the secondary electron beam will evaporate and coat the film material adhering to the top surface of the crucible body 10, forming a liquid that flows downward. Since there is a gap between the first inclined plane 210 or the first arc surface 220 and the top of the crucible sleeve 60, and the first inclined plane 210 or the first arc surface 220 has a certain buffering effect, the liquid film material will not immediately flow back into the crucible sleeve 60 to contaminate the film material in the crucible sleeve 60, nor will the crucible sleeve 60 crack due to the temperature difference. It will not flow back at the end of the entire process, improving the efficiency of evaporation coating, increasing the service life of the crucible body 10 and the crucible sleeve 60, and at the same time, the effect of evaporation coating is better. Description of the Drawings

[0023] Figure 1 It is a schematic diagram of the overall structure of an anti-backflow device for a crucible in electron beam evaporation coating according to the present invention.

[0024] Figure 2 It is a schematic diagram of the structure of the anti-adhesion plate assembly of an anti-backflow device for a crucible in electron beam evaporation coating according to the present invention.

[0025] Figure 3 It is a schematic diagram of a partial structure of an anti-backflow device for a crucible in electron beam evaporation coating according to the present invention.

[0026] Figure 4 It is a schematic diagram of a partial structure of an anti-backflow device for a crucible in electron beam evaporation coating according to the present invention.

[0027] Figure 5 It is a schematic diagram of a partial structure of an anti-backflow device for a crucible in electron beam evaporation coating according to the present invention.

[0028] Main element symbol description:

[0029] The main body 10, the bottom plate 20, the first coil 30, the second coil 40, the groove 50, the crucible sleeve 60, the connecting block 70, the magnetic conduction sheet 80, the anti-sputtering plate assembly 90, the first anti-sputtering plate 901, the second anti-sputtering plate 902, the third anti-sputtering plate 903, the fourth anti-sputtering plate 904, the second arc surface 100, the second inclined surface 110, the card slot 120, the fixed shaft 130, the pressing plate 140, the magnetic conduction adapter plate 150, the terminal protection cover 160, the protection plate 170, the support plate 180, the support column 190, the horizontal plane 200, the first inclined surface 210, the first arc surface 220.

[0030] The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings. Specific Embodiments

[0031] The following embodiments are described to assist in the understanding of the present application. The embodiments are not and should not in any way be construed as limiting the scope of protection of the present application.

[0032] In the following description, those skilled in the art will recognize that throughout this discussion, various components or portions thereof may be divided into separate components or may be integrated together (including being integrated within a single system or component).

[0033] Meanwhile, the connections between components or systems are not intended to be limited to direct connections. Instead, the data between these components may be modified, reformatted, or otherwise changed by intermediate components. Additionally, additional or fewer connections may be used. It should also be noted that the terms "coupled", "connected", or "input" should be understood to include direct connections, indirect connections through one or more intermediate devices, and wireless connections. Embodiment 1:

[0034] As Figure 1 shown, it is a schematic diagram of the overall structure of an anti-backflow device for a crucible in electron beam evaporation coating according to the present invention; as Figure 2 shown, it is a schematic diagram of the structure of the anti-sputtering plate assembly of an anti-backflow device for a crucible in electron beam evaporation coating according to the present invention; as Figure 3 shown, it is a schematic diagram of a partial structure of an anti-backflow device for a crucible in electron beam evaporation coating according to the present invention; as Figure 4 shown, it is a schematic diagram of a partial structure of an anti-backflow device for a crucible in electron beam evaporation coating according to the present invention; as Figure 5 shown, it is a schematic diagram of a partial structure of an anti-backflow device for a crucible in electron beam evaporation coating according to the present invention.

[0035] An anti-backflow device for a crucible in electron beam evaporation coating, comprising a crucible body 10. At the center of the top of the crucible body 10, there is a groove 50 with an upward opening. A crucible sleeve 60 is placed in the groove 50. The top surface of the crucible body 10 is a special-shaped surface, which includes a horizontal plane 200 that is vertically flush with the top of the crucible sleeve 60. At both the front and rear ends of the horizontal plane 200, they extend outward and upward to form a first inclined plane 210 or a first arc surface 220. There is a spacing between the first inclined plane 210 or the first arc surface 220 and the top edge of the crucible sleeve 60. When evaporating and coating the film material, the film material is added into the crucible sleeve 60. Inevitably, a small amount of the film material will adhere to the top surface of the crucible body 10. The electron beam enters the crucible sleeve 60 through the electron beam channel cavity for evaporation coating. At the same time, the electron beam will refract and splash onto the top surface of the crucible body 10 in the crucible sleeve 60 to form a secondary electron beam. At this time, the secondary electron beam will evaporate and coat the film material adhering to the top surface of the crucible body 10, forming a liquid that flows downward. Due to the fact that there is a spacing between the first inclined plane 210 or the first arc surface 220 and the top of the crucible sleeve 60, and the first inclined plane 210 or the first arc surface 220 has a certain buffering effect, the liquid film material will not immediately flow back into the crucible sleeve 60 to contaminate the film material in the crucible sleeve 60, nor will the crucible sleeve 60 crack due to the temperature difference, and there will be no backflow at the end of the whole process.

[0036] A deposition prevention plate assembly 90 that is connected to the upper part of the special-shaped surface and is adapted to its shape is provided. The deposition prevention plate assembly 90 abuts and fits against the top end of the crucible body 10. By setting the deposition prevention plate assembly 90, it is convenient to replace the deposition prevention plate assembly 90 after one process is completed, which will not affect the subsequent evaporation coating of the film material and improve the effect of evaporation coating.

[0037] The surface of the deposition prevention plate assembly 90 is provided with a nano-groove array to assist in blocking the backflow of the liquid film material.

[0038] The depth and inclination angle of the nano-grooves satisfy the relational formula: d = 0.2θ - 25 (where d is the groove depth / nm and θ is the inclination angle / °).

[0039] The anti - splashing plate assembly 90 includes a first anti - splashing plate 901, a second anti - splashing plate 902, a third anti - splashing plate 903, and a fourth anti - splashing plate 904. One end of the first anti - splashing plate 901 is connected to the second anti - splashing plate 902, and the third anti - splashing plate 903 and the fourth anti - splashing plate 904 are connected to both sides of the other end of the first anti - splashing plate 901. There is a gap between the second anti - splashing plate 902, the third anti - splashing plate 903, the fourth anti - splashing plate 904 and the top edge of the crucible sleeve 60. And the sides of the third anti - splashing plate 903 and the fourth anti - splashing plate 904 close to the top of the crucible sleeve 60 are inclined second arc surfaces 100, and the side of the second anti - splashing plate 902 close to the groove 50 is an inclined second inclined surface 110. When evaporation coating of the film material is required, the film material is added into the crucible sleeve 60. Inevitably, a small amount of the film material will adhere to the anti - splashing plate assembly 90. The electron beam enters the crucible sleeve 60 through the electron beam channel cavity for evaporation coating. At the same time, the electron beam will be refracted and splashed onto the anti - splashing plate assembly 90 in the crucible sleeve 60 to form a secondary electron beam. At this time, the secondary electron beam will evaporate - coat the film material adhering to the anti - splashing plate assembly 90, causing it to flow downward in a liquid state. Since there is a gap between the second anti - splashing plate 902, the third anti - splashing plate 903, the fourth anti - splashing plate 904 and the edge of the groove 50 opening, and the sides of the third anti - splashing plate 903 and the fourth anti - splashing plate 904 close to the groove 50 are inclined second arc surfaces 100, and the side of the second anti - splashing plate 902 close to the groove 50 is an inclined second inclined surface 110, the liquid - state film material will not flow back into the crucible sleeve 60 to contaminate the film material in the crucible sleeve 60, nor will the crucible sleeve 60 crack due to the temperature difference. Due to the setting of the anti - splashing plate assembly 90, the efficiency of evaporation coating is improved, and the service life of the crucible body 10 and the crucible sleeve 60 is also improved. At the same time, the effect of evaporation coating is better.

[0040] The first anti - splashing plate 901, the second anti - splashing plate 902, the third anti - splashing plate 903, and the fourth anti - splashing plate 904 are integrally formed, and their surfaces are all coated with a high - temperature - resistant coating, significantly improving the anti - adhesion and corrosion resistance.

[0041] The high - temperature - resistant coating is a boron nitride composite coating.

[0042] The inclination angle of the inclined second arc surface 100 of the third anti - splashing plate 903 and the fourth anti - splashing plate 904 is 135 degrees.

[0043] The inclination angle of the second inclined surface 110 of the second anti-sputtering plate 902 is 130°-140°, and this angle forms a 45° reflection angle with the electron beam incident direction (usually vertical or nearly vertical), so that the bombardment area of the secondary electron beam (generated by refraction) moves outside to the edge of the anti-sputtering plate, avoiding interference with the main film material in the crucible sleeve. When the angle of the second inclined surface 110 > 130°, the Reynolds number (Re) decreases from the turbulent flow region (Re > 4000) to the transitional flow region (2000 < Re < 4000), reducing the liquid film splash; when the angle < 140°, it avoids the droplet impact and rebound caused by the second inclined surface 110 being too steep.

[0044] A cooling and heat dissipation system is provided on the back of the anti-sputtering plate assembly 90, which improves the heat dissipation efficiency by 40% and is used to assist in slowing down the reflux of the film material.

[0045] It further includes a bottom plate 20, a first coil 30 and a second coil 40. The top of the bottom plate 20 is connected to the crucible body 10. On both sides of the front top of the crucible body 10, connection blocks 70 are connected and provided. There is a distance between the two connection blocks 70 to form the electron beam channel cavity. The first coils 30 are connected to both sides of the front end of the crucible body 10, and each first coil 30 is connected to its corresponding connection block 70. The second coil 40 is provided at the rear end of the crucible body 10, and the bottom end of the second coil 40 is connected to the bottom plate 20. Magnetic conduction sheets 80 are connected to both sides of the second coil 40. The connection block 70 is integrally formed with the crucible body 10. One side of the connection block 70 close to the top edge of the crucible sleeve 60 is the first arc surface 220.

[0046] A card slot 120 with an opening facing outwards is provided on one side of the connection block 70. A fixed shaft 130 is provided between the first coil 30 and the connection block 70. One end of the fixed shaft 130 passes through the first coil 30 and is clamped with the card slot 120. A pressing plate 140 is connected to the other end of the fixed shaft 130. The pressing plate 140 is used to fix the first coil 30 to prevent sliding displacement.

[0047] A magnetic conduction adapter plate 150 is provided in the card slot 120. The magnetic conduction adapter plate 150 is sleeved with the fixed shaft 130. The magnetic conduction adapter plate 150 is used to guide and concentrate the magnetic lines of force.

[0048] A terminal protection cover 160 is connected to the lower part of the first coil 30 to prevent the first coil 30 from being invaded by external dust, moisture, foreign objects, etc., ensuring normal operation and avoiding the occurrence of circuit failures and accidents.

[0049] A protection plate 170 is provided around the crucible body 10. The bottom end of the protection plate 170 is connected to the bottom plate 20. The protection plate 170 is used to block external dust, moisture, and foreign objects.

[0050] A support plate 180 is connected to the bottom end of the bottom plate 20, and support columns 190 are connected to the four corners at the bottom end of the support plate 180.

[0051] Advantages of the present invention: The present invention provides an anti-backflow device for a crucible in electron beam evaporation coating, including a crucible body 10. A groove 50 with an upward opening is provided at the center of the top of the crucible body 10. A crucible sleeve 60 is placed in the groove 50. The top surface of the crucible body 10 is a special-shaped surface, and the special-shaped surface includes a horizontal plane 200 that is vertically flush with the top of the crucible sleeve 60. Both the front and rear ends of the horizontal plane 200 extend outward and upward to form a first inclined surface 210 or a first arc surface 220. There is a gap between the first inclined surface 210 or the first arc surface 220 and the edge of the top opening of the crucible sleeve 60. When evaporating and coating the film material, the film material is added into the crucible sleeve 60. Inevitably, a small amount of the film material will adhere to the top surface of the crucible body 10. The electron beam enters the crucible sleeve 60 through the electron beam channel cavity for evaporation coating. At the same time, the electron beam will be refracted and splashed onto the top surface of the crucible body 10 in the crucible sleeve 60 to form a secondary electron beam. At this time, the secondary electron beam will evaporate and coat the film material adhering to the top surface of the crucible body 10, forming a liquid that flows downward. Since there is a gap between the first inclined surface 210 or the first arc surface 220 and the top of the crucible sleeve 60, and the first inclined surface 210 or the first arc surface 220 has a certain buffering effect, the liquid film material will not immediately flow back into the crucible sleeve 60 to contaminate the film material in the crucible sleeve 60, nor will the crucible sleeve 60 crack due to the temperature difference. It will not flow back at the end of the entire process, improving the efficiency of evaporation coating, increasing the service life of the crucible body 10 and the crucible sleeve 60, and at the same time, the effect of evaporation coating is better.

[0052] The above embodiments only represent several implementation manners of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the appended claims.

Claims

1. An anti-backflow device for a crucible in electron beam evaporation coating, comprising a crucible body (10), wherein a groove (50) with an upward opening is provided at the center of the top of the crucible body (10), and a crucible sleeve (60) is placed in the groove (50), and it is characterized in that: The top surface of the crucible body (10) is a special-shaped surface, which includes a horizontal plane (200) that is vertically flush with the top of the crucible sleeve (60). Both the front and rear ends of the horizontal plane (200) extend outward and upward to form a first inclined surface (210) or a first arc surface (220). There is a spacing between the first inclined surface (210) or the first arc surface (220) and the top edge of the crucible sleeve (60).

2. The anti-backflow device for a crucible in electron beam evaporation coating according to claim 1, characterized in that: A deposition prevention plate assembly (90) adapted to its shape is connected to the upper part of the special-shaped surface. The deposition prevention plate assembly (90) is in abutting contact with the top end of the crucible body (10). By providing the deposition prevention plate assembly (90), it is convenient to replace the deposition prevention plate assembly (90) after one process, which will not affect the subsequent evaporation coating of the film material and improve the effect of evaporation coating.

3. The anti-backflow device for the crucible in electron beam evaporation coating according to claim 2, characterized in that: The deposition prevention plate assembly (90) includes a first deposition prevention plate (901), a second deposition prevention plate (902), a third deposition prevention plate (903), and a fourth deposition prevention plate (904). One end of the first deposition prevention plate (901) is connected to the second deposition prevention plate (902), and both sides of the other end of the first deposition prevention plate (901) are connected to the third deposition prevention plate (903) and the fourth deposition prevention plate (904). There is a spacing between the second deposition prevention plate (902), the third deposition prevention plate (903), the fourth deposition prevention plate (904) and the top edge of the crucible sleeve (60). And the sides of the third deposition prevention plate (903) and the fourth deposition prevention plate (904) close to the top of the crucible sleeve (60) are inclined second arc surfaces (100), and the side of the second deposition prevention plate (902) close to the groove (50) is an inclined second inclined surface (110).

4. The anti-backflow device for a crucible in electron beam evaporation coating according to claim 3, characterized in that: The first deposition prevention plate (901), the second deposition prevention plate (902), the third deposition prevention plate (903), and the fourth deposition prevention plate (904) are integrally formed, and their surfaces are all coated with a high-temperature resistant coating, which significantly improves the anti-adhesion and corrosion resistance.

5. The anti-backflow device for crucibles in electron beam evaporation coating according to claim 4, characterized in that: The high-temperature resistant coating is a boron nitride composite coating.

6. The anti-backflow device for a crucible in electron beam evaporation coating according to claim 3, characterized in that: The inclination angle of the inclined second arc surface (100) of the third deposition prevention plate (903) and the fourth deposition prevention plate (904) is 135 degrees.

7. The anti-backflow device for a crucible in electron beam evaporation coating according to claim 3, characterized in that: The inclination angle of the second inclined surface (110) of the second deposition prevention plate (902) is 130 - 140 degrees. This angle forms a 45° reflection angle with the electron beam incident direction (usually vertical or nearly vertical), so that the bombardment area of the secondary electron beam (generated by refraction) moves outside to the edge of the deposition prevention plate, avoiding interference with the main film material in the crucible sleeve. When the angle of the second inclined surface (110) > 130°, the Reynolds number (Re) drops from the turbulent flow region (Re > 4000) to the transitional flow region (2000 < Re < 4000), reducing the liquid film splash; when the angle < 140°, it avoids the liquid droplets from hitting and rebounding due to the second inclined surface (110) being too steep.

8. The anti-backflow device for a crucible in electron beam evaporation coating according to claim 2, characterized in that: The surface of the deposition prevention plate assembly (90) is provided with a nano-groove array to assist in blocking the backflow of the film material in the liquid state.

9. The anti-backflow device for a crucible in electron beam evaporation coating according to claim 8, characterized in that: The depth and inclination angle of the nano-groove satisfy the relational formula: d = 0.2θ - 25 (where d is the groove depth / nm and θ is the inclination angle / °).

10. The anti-backflow device for crucibles in electron beam evaporation coating according to claim 8, characterized in that: The back of the anti-backflow plate assembly (90) is provided with a cooling and heat dissipation system, which improves the heat dissipation efficiency by 40% and is used to assist in slowing down the backflow of the film material.

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