A laser marking method based on the interface between silicon carbide substrate and polymer

Abstract

The present invention provides a laser marking method based on the interface between a silicon carbide substrate and a polymer, which utilizes the photothermal conversion at the contact interface between the silicon carbide substrate and the polymer film to achieve laser induced patterning. The method provided by the present invention does not require chemical etching and physical doping, and only requires a silicon carbide substrate to achieve laser marking on the surface of a polymer film, overcoming the problem that most polymers cannot be marked due to lack of laser responsiveness, while avoiding the overall filling of laser sensitive substances in the polymer, improving the laser marking effect, and facilitating large-scale promotion and application.

Description

Technical Field

[0001] The invention belongs to the technical field of marking, and relates to a laser marking method, and in particular to a laser marking method based on a silicon carbide substrate and a polymer interface. Background Art

[0002] Most polymer materials in life (such as polyethylene, polypropylene, thermoplastic polyurethane, etc.) need to be marked on their surfaces in some specific applications to provide information such as product production date, expiration date, serial number, and company logo.

[0003] Laser marking is one of the most widely used technologies in industry. The principle of laser marking polymers is that when high-energy laser irradiates the polymer surface, the material absorbs light energy and converts it into heat energy, causing a rapid photothermal conversion reaction, which causes carbonization and ablation of the material, ultimately forming a marking pattern.

[0004] Laser marking does not require ink, nor does it require the high-intensity energy drying process of ink printing technology, and it does not require solvents, so it is more environmentally friendly. Due to its fast marking, excellent durability, high contrast and environmentally friendly characteristics, it is widely used in surface marking of various materials such as plastic polymers, metals and ceramics. By changing the operating parameters of the laser beam such as scanning speed, current, spot size and line width, the laser marking effect on the material surface can be adjusted, including surface roughness, contrast and clarity of the mark, and color difference.

[0005] However, most polymer materials are not sensitive to near-infrared lasers and cannot undergo carbonization or foaming reactions under laser irradiation, which has prevented the popularization of laser marking technology. As the research deepened, researchers found that laser-sensitive substances can be introduced into the polymer matrix to improve its responsiveness to lasers.

[0006] Metal oxides are the most common type of substances that respond to lasers, such as antimony trioxide, bismuth trioxide, ferric oxide, molybdenum disulfide, etc., which are used to improve the laser responsiveness of polymer materials. However, the disadvantages of the overall filling of the above substances cannot be ignored: (1) The incorporation of laser-sensitive substances will affect the properties of the polymer matrix. For example, agglomeration will lead to a decrease in mechanical properties. In addition, laser-sensitive substances (such as black CNTs, yellow Bi 2 O 3 , white BiOCl, etc.) will affect the color of the polymer matrix, especially for transparent polymers (such as PVA, PMMA, TPU, etc.), this effect is fatal. (2) Metal oxide additives have certain toxicity, which limits their application in food, medicine and other industries.

[0007] Therefore, it can be seen that how to provide a laser marking method to overcome the problem that most polymers cannot be marked due to their lack of laser responsiveness, while avoiding the overall filling of laser sensitive substances in the polymer and improving the laser marking effect has become an urgent problem that technical personnel in this field need to solve. Summary of the invention

[0008] The purpose of the present invention is to provide a laser marking method based on the interface of a silicon carbide substrate and a polymer. The method does not require chemical etching and physical doping, and only requires a silicon carbide substrate to achieve laser marking on the surface of a polymer film, thereby overcoming the problem that most polymers cannot be marked due to lack of laser responsiveness. At the same time, it avoids filling the polymer with laser sensitive substances as a whole, thereby improving the laser marking effect and facilitating large-scale promotion and application.

[0009] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0010] The present invention provides a laser marking method based on the interface between a silicon carbide substrate and a polymer. The laser marking method utilizes light-heat conversion at the contact interface between the silicon carbide substrate and the polymer film to realize laser-induced patterning.

[0011] The surface flatness of the silicon carbide substrate is 20-30 μm, for example, 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm or 30 μm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0012] The present invention utilizes a highly flat silicon carbide substrate as a base for laser marking of polymer films, which not only avoids directly adding laser sensitive substances into the polymer to affect the color and mechanical properties of the film, but also, compared with other substrates, the silicon carbide substrate is very stable in terms of heat, chemistry, and mechanics, and its own structure will not be destroyed due to the high temperature of the laser after repeated use.

[0013] In addition, the laser marking method provided by the present invention utilizes the photothermal conversion at the contact interface between the silicon carbide substrate and the polymer film to achieve laser-induced patterning, which meets the requirements of industrialized, continuous, efficient and large-scale marking of various polymer materials. In addition, during the marking process, text and patterns with different contrast and clarity can be obtained on the surface of the polymer film by changing the laser power, which is more advantageous than the marking obtained by traditional cutting and etching techniques.

[0014] Furthermore, the laser marking method provided by the present invention does not require chemical etching and physical doping, and only requires a silicon carbide substrate to achieve laser marking on the surface of a polymer film, which effectively reduces costs, prevents environmental pollution, and meets green and environmentally friendly production requirements.

[0015] Preferably, the laser marking method comprises the following steps:

[0016] (1) preparing a silicon carbide substrate;

[0017] (2) A transparent polymer film is bonded to the surface of a silicon carbide substrate, and a laser is used to irradiate the contact interface between the silicon carbide substrate and the polymer film. The laser energy is absorbed by the interface and converted into heat energy, causing the polymer film to melt and carbonize in situ. Black carbon particles are generated along the laser path and attached to the surface of the polymer film, and finally the laser marking is completed.

[0018] Preferably, the preparation of the silicon carbide substrate in step (1) adopts a physical vapor transport method, which specifically includes the following steps:

[0019] (1.1) Filling the bottom of a graphite crucible with silicon carbide powder and fixing a silicon carbide seed crystal on the top of the crucible cover;

[0020] (1.2) heating the graphite crucible to a first temperature and maintaining the temperature of the silicon carbide seed crystal lower than the temperature of the silicon carbide powder. When the gas pressure in the reaction chamber exceeds the saturated vapor pressure of the silicon carbide crystal, the gas phase silicon carbide sublimated in the graphite crucible crystallizes on the surface of the silicon carbide seed crystal to form a silicon carbide ingot.

[0021] (1.3) The silicon carbide ingot is flat-ground to obtain a silicon carbide substrate.

[0022] Preferably, the heating method of the graphite crucible in step (1.2) includes radio frequency induction heating or resistance heating.

[0023] Preferably, the first temperature in step (1.2) is 2300-2400°C, for example, it can be 2300°C, 2310°C, 2320°C, 2330°C, 2340°C, 2350°C, 2360°C, 2370°C, 2380°C, 2390°C or 2400°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0024] Preferably, the temperature of the silicon carbide seed crystal in step (1.2) is 50-100°C lower than the temperature of the silicon carbide powder, for example, it can be 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C or 100°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0025] Preferably, the center thickness and edge thickness of the silicon carbide ingot in step (1.2) are independently 90-100 mm, for example, 90 mm, 91 mm, 92 mm, 93 mm, 94 mm, 95 mm, 96 mm, 97 mm, 98 mm, 99 mm or 100 mm, but are not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0026] Preferably, the laser in step (2) comprises a semiconductor pulse laser.

[0027] Preferably, the wavelength of the laser in step (2) is 1000-1100 nm, for example, it can be 1000 nm, 1010 nm, 1020 nm, 1030 nm, 1040 nm, 1050 nm, 1060 nm, 1070 nm, 1080 nm, 1090 nm or 1100 nm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0028] Preferably, the scanning speed of the laser in step (2) is 600-1000 mm / s, for example, it can be 600 mm / s, 650 mm / s, 700 mm / s, 750 mm / s, 800 mm / s, 850 mm / s, 900 mm / s, 950 mm / s or 1000 mm / s, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0029] Preferably, the material of the polymer film in step (2) includes any one of polyvinyl alcohol, polycarbonate, polyethylene terephthalate or polybutylene terephthalate.

[0030] Preferably, the laser marking in step (2) is performed using a laser marking machine, and the output power of the laser marking machine is 20-40 W, for example, it can be 20 W, 22 W, 24 W, 26 W, 28 W, 30 W, 32 W, 34 W, 36 W, 38 W or 40 W, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0031] The laser marking method provided by the present invention is performed by using a conventional laser marking machine, as long as the laser marking function can be achieved, so the specific model and structure of the laser marking machine are not particularly limited herein.

[0032] Preferably, the depth of the laser marking in step (2) is 200-400 μm, for example, it can be 200 μm, 220 μm, 240 μm, 260 μm, 280 μm, 300 μm, 320 μm, 340 μm, 360 μm, 380 μm or 400 μm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0033] As a preferred technical solution of the present invention, the laser marking method utilizes the photothermal conversion at the contact interface between the silicon carbide substrate and the polymer film to realize laser induced patterning, and specifically includes the following steps:

[0034] (1) Preparing a silicon carbide substrate by a physical vapor transport method, comprising:

[0035] (1.1) Filling the bottom of a graphite crucible with silicon carbide powder and fixing a silicon carbide seed crystal on the top of the crucible cover;

[0036] (1.2) heating the graphite crucible to 2300-2400°C by radio frequency induction heating or resistance heating, and maintaining the temperature of the silicon carbide seed crystal 50-100°C lower than the temperature of the silicon carbide powder. When the gas pressure in the reaction chamber exceeds the saturated vapor pressure of the silicon carbide crystal, the gas phase silicon carbide sublimated in the graphite crucible crystallizes on the surface of the silicon carbide seed crystal to form a silicon carbide ingot with a center thickness and an edge thickness of 90-100 mm respectively.

[0037] (1.3) The silicon carbide ingot is flat-ground to obtain a silicon carbide substrate with a surface flatness of 20-30 μm.

[0038] (2) A transparent polymer film is bonded to the surface of a silicon carbide substrate. A semiconductor pulse laser with a wavelength of 1000-1100 nm is irradiated to the contact interface between the silicon carbide substrate and the polymer film using a laser marking machine with an output power of 20-40 W. The scanning speed is controlled to be 600-1000 mm / s. The laser energy is absorbed by the interface and converted into heat energy, causing the polymer film to melt and undergo in-situ carbonization reaction. Black carbon particles are generated along the laser route and attached to the surface of the polymer film, and finally a laser marking with a depth of 200-400 μm is completed.

[0039] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] (1) The present invention uses a highly flat silicon carbide substrate as a substrate for laser marking of polymer films, which not only avoids directly adding laser sensitive substances into the polymer to affect the color and mechanical properties of the film, but also, compared with other substrates, the silicon carbide substrate is very stable in terms of heat, chemistry, and mechanics, and its own structure will not be destroyed due to the high temperature of the laser after repeated use;

[0042] (2) The laser marking method provided by the present invention utilizes the photothermal conversion at the contact interface between the silicon carbide substrate and the polymer film to achieve laser-induced patterning, which meets the requirements of industrialized, continuous, efficient and large-scale marking of various polymer materials. In addition, during the marking process, texts and patterns with different contrast and clarity can be obtained on the surface of the polymer film by changing the laser power, which is more advantageous than the marking obtained by traditional cutting and etching techniques.

[0043] (3) The laser marking method provided by the present invention does not require chemical etching and physical doping, and only requires a silicon carbide substrate to achieve laser marking on the surface of a polymer film, which effectively reduces costs, prevents environmental pollution, and meets green and environmentally friendly production requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a schematic diagram of the laser marking method provided by the present invention.

[0045] Wherein: 1-silicon carbide substrate; 2-polymer film; 3-semiconductor pulse laser; 4-marking pattern. DETAILED DESCRIPTION

[0046] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0047] The present invention provides a laser marking method based on the interface between a silicon carbide substrate and a polymer, such as Figure 1 As shown, the laser marking method utilizes the photothermal conversion at the contact interface between the silicon carbide substrate 1 and the polymer film 2 to achieve laser induced patterning, and specifically includes the following steps:

[0048] (1) A silicon carbide substrate 1 is prepared by a physical vapor transport method, comprising:

[0049] (1.1) Filling the bottom of a graphite crucible with silicon carbide powder and fixing a silicon carbide seed crystal on the top of the crucible cover;

[0050] (1.2) heating the graphite crucible to 2300-2400°C by radio frequency induction heating or resistance heating, and maintaining the temperature of the silicon carbide seed crystal 50-100°C lower than the temperature of the silicon carbide powder. When the gas pressure in the reaction chamber exceeds the saturated vapor pressure of the silicon carbide crystal, the gas phase silicon carbide sublimated in the graphite crucible crystallizes on the surface of the silicon carbide seed crystal to form a silicon carbide ingot with a center thickness and an edge thickness of 90-100 mm respectively.

[0051] (1.3) The silicon carbide ingot is flat-ground to obtain a silicon carbide substrate 1 with a surface flatness of 20-30 μm.

[0052] (2) A transparent polymer film 2 is attached to the surface of a silicon carbide substrate 1, and a semiconductor pulse laser 3 with a wavelength of 1000-1100 nm is irradiated on the contact interface between the silicon carbide substrate 1 and the polymer film 2 using a laser marking machine with an output power of 20-40 W. The scanning speed is controlled to be 600-1000 mm / s. The laser energy is absorbed by the interface and converted into heat energy, causing the polymer film 2 to melt and undergo an in-situ carbonization reaction. Black carbon particles are generated along the laser path and attached to the surface of the polymer film 2. Finally, a laser marking with a depth of 200-400 μm is completed to form a marking pattern 4.

[0053] Example 1

[0054] This embodiment provides a laser marking method based on the interface between a silicon carbide substrate and a polymer, such as Figure 1 As shown, the laser marking method utilizes the photothermal conversion at the contact interface between the silicon carbide substrate 1 and the polymer film 2 to achieve laser induced patterning, and specifically includes the following steps:

[0055] (1) A silicon carbide substrate 1 is prepared by a physical vapor transport method, comprising:

[0056] (1.1) Filling the bottom of a graphite crucible with silicon carbide powder and fixing a silicon carbide seed crystal on the top of the crucible cover;

[0057] (1.2) heating the graphite crucible to 2350°C by radio frequency induction heating, and maintaining the temperature of the silicon carbide seed crystal lower than the temperature of the silicon carbide powder by 70±5°C. When the gas pressure in the reaction chamber exceeds the saturated vapor pressure of the silicon carbide crystal, the gas phase silicon carbide sublimated in the graphite crucible crystallizes on the surface of the silicon carbide seed crystal to form a silicon carbide ingot with a center thickness of 90 mm and an edge thickness of 89 mm;

[0058] (1.3) The silicon carbide ingot is flat-ground to obtain a silicon carbide substrate 1 with a surface flatness of 22 μm.

[0059] (2) A transparent polymer film 2 (with a degree of polymerization of 120,000-150,000) made of polyvinyl alcohol is adhered to the surface of the silicon carbide substrate 1. A semiconductor pulse laser 3 with a wavelength of 1064 nm is irradiated to the contact interface between the silicon carbide substrate 1 and the polymer film 2 using a laser marking machine with an output power of 30 W. The scanning speed is controlled to be 800 mm / s. The laser energy is absorbed by the interface and converted into heat energy, causing the polymer film 2 to melt and undergo an in-situ carbonization reaction. Black carbon particles are generated along the laser route and attached to the surface of the polymer film 2. Finally, laser marking with a depth of 300 μm is completed to form a marking pattern 4.

[0060] The laser marking method provided in this embodiment can mark the production date, expiration date, QR code and other text, images and symbols on the surface of the polymer film 2, thereby realizing the identification, marking and modification of the product.

[0061] Example 2

[0062] This embodiment provides a laser marking method based on the interface between a silicon carbide substrate and a polymer, such as Figure 1 As shown, the laser marking method utilizes the photothermal conversion at the contact interface between the silicon carbide substrate 1 and the polymer film 2 to achieve laser induced patterning, and specifically includes the following steps:

[0063] (1) A silicon carbide substrate 1 is prepared by a physical vapor transport method, comprising:

[0064] (1.1) Filling the bottom of a graphite crucible with silicon carbide powder and fixing a silicon carbide seed crystal on the top of the crucible cover;

[0065] (1.2) heating the graphite crucible to 2300°C by radio frequency induction heating, and maintaining the temperature of the silicon carbide seed crystal lower than the temperature of the silicon carbide powder by 55±5°C. When the gas pressure in the reaction chamber exceeds the saturated vapor pressure of the silicon carbide crystal, the gas phase silicon carbide sublimated in the graphite crucible crystallizes on the surface of the silicon carbide seed crystal to form a silicon carbide ingot with a center thickness of 92 mm and an edge thickness of 93 mm;

[0066] (1.3) The silicon carbide ingot is flat-ground to obtain a silicon carbide substrate 1 with a surface flatness of 22 μm.

[0067] (2) A transparent polymer film 2 (with a degree of polymerization of 100,000-150,000) made of polycarbonate is adhered to the surface of the silicon carbide substrate 1. A semiconductor pulse laser 3 with a wavelength of 1064 nm is irradiated to the contact interface between the silicon carbide substrate 1 and the polymer film 2 using a laser marking machine with an output power of 20 W. The scanning speed is controlled to be 600 mm / s. The laser energy is absorbed by the interface and converted into heat energy, causing the polymer film 2 to melt and undergo an in-situ carbonization reaction. Black carbon particles are generated along the laser route and attached to the surface of the polymer film 2. Finally, laser marking with a depth of 200 μm is completed to form a marking pattern 4.

[0068] The laser marking method provided in this embodiment can mark the production date, expiration date, QR code and other text, images and symbols on the surface of the polymer film 2, thereby realizing the identification, marking and modification of the product.

[0069] Example 3

[0070] This embodiment provides a laser marking method based on the interface between a silicon carbide substrate and a polymer, such as Figure 1 As shown, the laser marking method utilizes the photothermal conversion at the contact interface between the silicon carbide substrate 1 and the polymer film 2 to achieve laser induced patterning, and specifically includes the following steps:

[0071] (1) A silicon carbide substrate 1 is prepared by a physical vapor transport method, comprising:

[0072] (1.1) Filling the bottom of a graphite crucible with silicon carbide powder and fixing a silicon carbide seed crystal on the top of the crucible cover;

[0073] (1.2) heating the graphite crucible to 2400°C by radio frequency induction heating, and maintaining the temperature of the silicon carbide seed crystal lower than the temperature of the silicon carbide powder by 95±5°C. When the gas pressure in the reaction chamber exceeds the saturated vapor pressure of the silicon carbide crystal, the gas phase silicon carbide sublimated in the graphite crucible crystallizes on the surface of the silicon carbide seed crystal to form a silicon carbide ingot with a center thickness of 100 mm and an edge thickness of 98 mm;

[0074] (1.3) The silicon carbide ingot is flat-ground to obtain a silicon carbide substrate 1 with a surface flatness of 18 μm.

[0075] (2) A transparent polymer film 2 (with a degree of polymerization of 200,000-220,000) made of polyethylene terephthalate is adhered to the surface of the silicon carbide substrate 1. A semiconductor pulse laser 3 with a wavelength of 1064 nm is irradiated to the contact interface between the silicon carbide substrate 1 and the polymer film 2 using a laser marking machine with an output power of 40 W. The scanning speed is controlled to be 1000 mm / s. The laser energy is absorbed by the interface and converted into heat energy, causing the polymer film 2 to melt and undergo an in-situ carbonization reaction. Black carbon particles are generated along the laser route and attached to the surface of the polymer film 2. Finally, a laser marking with a depth of 400 μm is completed to form a marking pattern 4.

[0076] The laser marking method provided in this embodiment can mark the production date, expiration date, QR code and other text, images and symbols on the surface of the polymer film 2, thereby realizing the identification, marking and modification of the product.

[0077] Comparative Example 1

[0078] This comparative example provides a laser marking method. Except for changing the surface flatness of the silicon carbide substrate 1 to 40 μm by adjusting the preparation conditions, the remaining steps and conditions are the same as those in Example 1, and thus will not be described in detail here.

[0079] Compared with Example 1, since the surface flatness of the silicon carbide substrate 1 is changed to 40 μm in this comparative example, the film and the substrate are not closely attached, the light-to-heat conversion effect is poor, and the definition of the transferred pattern is reduced.

[0080] Comparative Example 2

[0081] This comparative example provides a laser marking method. Except that the silicon carbide substrate 1 is replaced by a carbon nanotube-doped polyvinylidene fluoride substrate having the same surface flatness, the remaining steps and conditions are the same as those in Example 1, and thus will not be described in detail here.

[0082] Compared with Example 1, since the silicon carbide substrate 1 is replaced by a carbon nanotube-doped polyvinylidene fluoride substrate in this comparative example, the substrate has poor mechanical properties and will bend and deform after several uses, thereby affecting the fit between the substrate and the film, the photothermal conversion effect becomes worse, and the laser pattern is more blurred. After being reused dozens of times, the substrate is pierced by the laser, making it impossible to reuse the substrate.

[0083] It can be seen that the present invention uses a highly flat silicon carbide substrate as a base for laser marking of polymer films, which not only avoids directly adding laser sensitive substances into the polymer to affect the color and mechanical properties of the film, but also, compared with other substrates, the silicon carbide substrate is very stable in terms of heat, chemistry, and mechanics, and its own structure will not be destroyed due to the high temperature of the laser after repeated use.

[0084] In addition, the laser marking method provided by the present invention utilizes the photothermal conversion at the contact interface between the silicon carbide substrate and the polymer film to achieve laser-induced patterning, which meets the requirements of industrialized, continuous, efficient and large-scale marking of various polymer materials. In addition, during the marking process, text and patterns with different contrast and clarity can be obtained on the surface of the polymer film by changing the laser power, which is more advantageous than the marking obtained by traditional cutting and etching techniques.

[0085] Furthermore, the laser marking method provided by the present invention does not require chemical etching and physical doping, and only requires a silicon carbide substrate to achieve laser marking on the surface of a polymer film, which effectively reduces costs, prevents environmental pollution, and meets green and environmentally friendly production requirements.

[0086] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A laser marking method based on the interface between a silicon carbide substrate and a polymer, characterized in that: The laser marking method utilizes the photothermal conversion at the contact interface between the silicon carbide substrate and the polymer film to achieve laser induced patterning; Wherein, the surface flatness of the silicon carbide substrate is 20-30 μm.

2. The laser marking method according to claim 1, characterized in that: The laser marking method comprises the following steps: (1) preparing a silicon carbide substrate; (2) A transparent polymer film is bonded to the surface of a silicon carbide substrate, and a laser is used to irradiate the contact interface between the silicon carbide substrate and the polymer film. The laser energy is absorbed by the interface and converted into heat energy, causing the polymer film to melt and carbonize in situ. Black carbon particles are generated along the laser path and attached to the surface of the polymer film, and finally the laser marking is completed.

3. The laser marking method according to claim 2, characterized in that: The laser in step (2) includes a semiconductor pulse laser.

4. The laser marking method according to claim 2, characterized in that: The wavelength of the laser in step (2) is 1000-1100nm.

5. The laser marking method according to claim 2, characterized in that: The scanning speed of the laser in step (2) is 600-1000 mm / s.

6. The laser marking method according to claim 2, characterized in that: The material of the polymer film in step (2) includes any one of polyvinyl alcohol, polycarbonate, polyethylene terephthalate or polybutylene terephthalate.

7. The laser marking method according to claim 2, characterized in that: The laser marking in step (2) is performed using a laser marking machine.

8. The laser marking method according to claim 7, characterized in that: The output power of the laser marking machine is 20-40W.

9. The laser marking method according to claim 2, characterized in that: The depth of the laser marking in step (2) is 200-400 μm.

10. The laser marking method according to any one of claims 1 to 9, characterized in that: The laser marking method utilizes the photothermal conversion at the contact interface between the silicon carbide substrate and the polymer film to realize laser induced patterning, and specifically comprises the following steps: (1) preparing a silicon carbide substrate with a surface flatness of 20-30 μm; (2) A transparent polymer film is bonded to the surface of a silicon carbide substrate. A semiconductor pulse laser with a wavelength of 1000-1100 nm is irradiated to the contact interface between the silicon carbide substrate and the polymer film using a laser marking machine with an output power of 20-40 W. The scanning speed is controlled to be 600-1000 mm / s. The laser energy is absorbed by the interface and converted into heat energy, causing the polymer film to melt and undergo in-situ carbonization reaction. Black carbon particles are generated along the laser route and attached to the surface of the polymer film, and finally a laser marking with a depth of 200-400 μm is completed.

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