Hydrophobic rearview mirror and method of making the same

Abstract

The present application relates to the technical field of rearview mirror, in particular to a hydrophobic rearview mirror and a preparation method thereof, wherein the hydrophobic rearview mirror comprises at least one medium layer, at least one metal layer and at least one reflection-increasing layer which are sequentially formed on a substrate; wherein the reflection-increasing layer comprises an outer film layer, and the outer film layer is selected from at least one of a ZTO film layer deposited by magnetron sputtering based on an MF power source or a HiPIMS power source and a ZnSnOx film layer deposited by magnetron sputtering based on a HiPIMS power source. The hydrophobic rearview mirror provided by the present application can effectively improve the hydrophobic performance thereof, and the hydrophobic performance thereof almost does not decline after multiple rubbings.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of rearview mirror, in particular to a hydrophobic rearview mirror and a preparation method thereof. BACKGROUND

[0002] The automobile rearview mirror is located on the left and right sides of the head of the automobile and the front of the inside of the automobile. The automobile rearview mirror reflects the situation behind, on the side and below the automobile, and plays the role of the "second eye", which expands the visual field range of the driver.

[0003] When driving in the rain, the automobile rearview mirror is easy to stick with water droplets or water marks, which greatly affects the field of view of the driver and poses a great threat to driving safety. In order to eliminate the water droplets and water marks attached to the rearview mirror, in addition to manual wiping, people have come up with many ways, such as using a device similar to the windshield wiper device or a hot air type water droplet removal device. But these two ways need to increase the motor and other additional equipment, which has the defects of complex structure, large size, easy to damage, difficult to maintain and high cost.

[0004] In view of this situation, some drivers directly apply wax or waterproof agent on the lens of the outside rearview mirror to remove water droplets and water marks, such as the automobile rearview mirror rainproof agent disclosed in the Chinese patent with the publication number CN107325665B. Although these waterproof treatments are convenient, fast, low in cost, they are easy to be washed away by rain or manually scraped off during use, have a short service life, i.e. low in life span, so the driver needs to repeatedly waterproof the lens of the outside rearview mirror, which causes great inconvenience to the driver. At the same time, although the application of the hydrophilic material on the surface of the outside rearview mirror can avoid the fogging of the mirror surface or prevent rain, when the rain is too heavy, the thickness of the water film formed on the mirror surface is not uniform, so it is easy to form a distorted image on the mirror surface. If the hydrophilic material is applied to the surface of the inside rearview mirror, it has self-cleaning ability but cannot prevent fingerprints, which seriously affects the normal use of the inside rearview mirror. SUMMARY

[0005] In order to overcome the defects of the prior art, the technical problem to be solved by the present application is to provide a hydrophobic rearview mirror with high life span and environmental stability and a preparation method thereof.

[0006] In order to solve the above technical problem, the present application provides a hydrophobic rearview mirror, which comprises at least one dielectric layer, at least one metal layer and at least one reflection-increasing layer formed in sequence on a substrate.

[0007] The reflection-increasing layer comprises an outer film layer, and the outer film layer is selected from at least one of a ZTO film layer based on MF power or HiPIMS power magnetron sputtering deposition, a ZnSnO x film layer based on HiPIMS power magnetron sputtering deposition.

[0008] Further provided is a method for preparing the hydrophobic rearview mirror, which comprises sequentially forming at least one dielectric layer, at least one metal layer and at least one reflection-increasing layer on a substrate based on a magnetron sputtering process;

[0009] The dielectric layer is formed based on MF, DC or HiPIMS power magnetron sputtering deposition;

[0010] The metal layer is formed based on HiPIMS power magnetron sputtering deposition.

[0011] The hydrophobic rearview mirror has the advantages that: the hydrophobic film layer ZTO film layer or ZnSnO x film layer formed on the rearview mirror surface by MF power or HiPIMS power magnetron sputtering has almost no signs of attenuation in hydrophobicity after multiple rubbings, i.e., the service life of the film layer is improved. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 Fig. 1 shows a structure schematic diagram of a hydrophobic rearview mirror in a specific embodiment of the present application;

[0013] Figure 2 Fig. 2 shows a structure schematic diagram of another hydrophobic rearview mirror in a specific embodiment of the present application;

[0014] Figure 3 Fig. 5 shows a film surface reflection curve of Example 5 of the present application; DETAILED DESCRIPTION

[0015] To describe the technical content, purposes and effects of the present application in detail, the following will be described in combination with the embodiments and the accompanying drawings.

[0016] Referring to Figure 1 Fig. 1 shows a hydrophobic rearview mirror, which comprises at least one dielectric layer 2, at least one metal layer 3 and at least one reflection-increasing layer 4 formed on a substrate 1 in sequence; wherein the reflection-increasing layer 4 comprises an outer film layer, and the outer film layer is selected from at least one of ZTO film layer formed based on MF power or HiPIMS power magnetron sputtering deposition and ZnSnO x film layer formed based on HiPIMS power magnetron sputtering deposition.

[0017] The ZTO film layer is formed by using MF or HiPIMS power to plate a target material ZTO (ceramic ZnSn03), and the ZnSn0 x film layer is formed by using HiPIMS power to plate a target material ZnSn, and their hydrophobicity (characterized by water contact angle) shows high stability in different preparation processes, as shown in Table 1. At the same time, due to its high refractive index, it can be applied to the outermost layer of the reflection-increasing layer of the mirror surface.

[0018] Table 1

[0019]

[0020] As can be seen from Table 1, ZnSnO x The outermost layer of the film layer as the mirror surface of the rearview mirror has a water contact angle greater than 90° at three different preparation process stages (the rearview mirror baking process) of non-annealing (before baking), 690°C annealing (after baking) and 720°C annealing (after baking), indicating that it has stable hydrophobic properties. At the same time, due to its stable hydrophobic properties, it can stably reduce the residence time of raindrops on the outer rearview mirror surface, thereby maintaining the stability of the field of view of the outer rearview mirror, and when used as an inner rearview mirror, it can exhibit strong anti-fingerprint performance.

[0021] ZnSnO x The film layer and the ZTO film layer have greatly improved compactness and surface hardness, increased water contact angle, and almost no decay of the water contact angle after multiple rubbings, compared with the use of the MF power source. Compared with the hydrophobic film layer formed by the traditional sol / gel method, the ZnSnO x The film layer and the ZTO film layer have higher service life and environmental stability.

[0022] Preferably, the thickness of the outer film layer is 25-75 nm, and the refractive index is 1.97-2.72. Among them, the refractive index of the ZTO film layer formed by using the MF power source and the ZTO target is preferably 1.97-2.10, the refractive index of the ZTO film layer formed by using the HiPIMS power source and the ZTO target is preferably 2.10-2.72, and the refractive index of the ZnSnO x The refractive index of the film layer is preferably 2.10-2.72.

[0023] In one embodiment, the metal layer is made of one of chromium metal, chromium alloy, titanium metal, titanium alloy, chromium metal oxide or nitride, chromium alloy oxide or nitride; and the metal layer is deposited by HiPIMS at a peak power of 190-280 kW and a duty cycle of 5-10%. Preferably, the metal layer is made of Cr or CrN. In this embodiment, the Cr / CrN metal layer is preferably deposited by HiPIMS magnetron sputtering. Compared with the Cr / CrN metal layer deposited by DC power, the Cr / CrN metal layer deposited by HiPIMS power has higher thermal ductility, adhesion between layers, compactness, hardness, wear resistance, ionization rate and heat transfer coefficient, and thus the use of the Cr / CrN as the metal layer can effectively solve the cracking problem caused by the large difference in thermal expansion coefficient between the metal layer and the substrate after baking. At the same time, the reflection-increasing layer is formed on the metal layer, and thus the high hardness of the metal layer can further improve the hardness of the entire mirror film, greatly reduce the decay of the water contact angle of the hydrophobic layer after multiple rubbings, and effectively prevent the rearview mirror lens from being scratched by fine sand, dust and the like during processing or transportation.

[0024] Preferably, the thickness of the metal layer is 1-90 nm.

[0025] In one embodiment, the reflection-increasing layer further comprises an inner film layer group located inside the outer film layer group, and the inner film layer group is composed of at least one inner film layer, and the material of the inner film layer is selected from at least one of SiZrO x , SiAlZrO x , SiZrO x N y , SiAlZrO x N y , wherein 1≤x≤3, 1≤y≤3. The inner film layer and the outer film layer form a low / high refractive index film layer stack, which increases the reflection of visible light or blue light (469 nm). In this embodiment, the inner film layer as a low refractive index layer must contain at least one of SiZrO x , SiAlZrO x , SiZrO x N y , SiAlZrO x N y , wherein 1≤x≤3, 1≤y≤3, to further enhance the hardness of the entire film layer.

[0026] Preferably, the thickness of the inner film layer is 35-95 nm, and the refractive index of the inner film layer is 1.55-1.82.

[0027] In one embodiment, the material of the dielectric layer is selected from at least one of AZO, Ti alloy, NbO x , TiO x , NiCr, NiCrO x , ZnAlO x , ZnO x , SnO x , ZnSnO x , SiAlZrN x , SiAlN x , SiN x , SiZrN x , ZTO, ITO, wherein 1≤x≤3, 1≤y≤3. The dielectric layer is arranged between the substrate and the metal layer to enhance the adhesion of the two while adjusting the color of the substrate (generally white or colored glass). At the same time, since the overall thickness of the metal layer is thick, it is difficult for visible light to penetrate the metal layer, thus allowing the reflection-increasing layer on the metal layer and the dielectric layer under the metal layer to independently adjust the color and function of the two sides of the metal layer without interfering with each other.

[0028] Preferably, the thickness of the dielectric layer is 1-500 nm, and the refractive index of the dielectric layer is 1.58-2.72.

[0029] In one embodiment, the substrate is selected from single flat white or colored glass with a thickness of 0.7-8.0 mm.

[0030] The aforementioned method for preparing a hydrophobic rearview mirror is based on a magnetron sputtering process, and at least one dielectric layer, at least one metal layer, and at least one reflection-increasing layer are sequentially formed on the substrate.

[0031] The dielectric layer is formed by magnetron sputtering deposition based on an MF, DC, or HiPIMS power source.

[0032] The metal layer is formed by magnetron sputtering deposition based on a HiPIMS power source.

[0033] Examples 1-6 and Comparative Examples 1-3

[0034] The method for preparing a hydrophobic rearview mirror comprises the following steps:

[0035] S1. After washing and drying the substrate, the substrate is placed in a magnetron sputtering coating machine, and at least one dielectric layer, at least one metal layer, and at least one reflection-increasing layer are sequentially formed on the surface of the substrate to obtain a raw piece.

[0036] The specific parameters of the magnetron sputtering process of each layer are shown in Tables 2-10, and the substrate material selection (glass material and thickness) is shown in Table 11. The labels of each layer correspond Figure 2 ;

[0037] S2, the original film is conveyed to the powder spraying machine for powder spraying and film collecting, and after a package is collected, drying and sealing packaging are performed;

[0038] S3, the original film is cut into a size suitable for the oven bending furnace by using a glass cutting machine, and then the original film is cleaned for the first time by using pure water and a brush to clean the dirt on the surface of the original film, and then drying is performed, so as to provide clean conditions for the next glass bending process, to avoid the occurrence of problems such as spots and distortion of the mirror surface;

[0039] S4, the cleaned original film is high-temperature oven bent and formed on a mold in the oven bending furnace to obtain a lens, and the commonly used curvature is 1260±60, 1400±150, 1800±200, and 2000±250. In the embodiment and the comparative example, the same curvature, i.e., 1400±150, is adopted.

[0040] In the embodiment, the self-weight forming technology is used, and the specific parameters are as follows (taking the heating air temperature as the standard): heating process: preheating temperature 570℃, preheating time 240s; heating temperature 720℃, heating time 240s; annealing temperature 300℃, annealing time 120s.

[0041] S5, the oven-bent lens is cooled, and a special-shaped cutting machine is used to cut the desired shape.

[0042] S6, the cut lens is detected for lens size stability and coating effect (excluding lenses with defects such as scratches, pitting, distortion, and edge explosion), and finally after further chamfering / grinding processing, cleaning processing, and final inspection, the producible automobile rearview mirror lens is obtained.

[0043] Table 2

[0044]

[0045] Table 3

[0046]

[0047]

[0048] Table 4

[0049]

[0050]

[0051] Table 5

[0052]

[0053] Table 6

[0054]

[0055]

[0056] Table 7

[0057]

[0058]

[0059] Table 8

[0060]

[0061]

[0062] Table 9

[0063]

[0064] Table 10

[0065]

[0066]

[0067] Table 11

[0068] Item Substrate Film layer designation 11 Comparative Example 1 White glass 3.8 mm Comparative Example 2 White glass 3.8 mm Comparative Example 3 White glass 3.8 mm Example 1 White glass 3.8 mm Example 2 White glass 3.8 mm Example 3 White glass 3.8 mm Example 4 White glass 3.5 mm Example 5 White glass 3.5 mm Example 6 White glass 3.5 mm

[0069] Detection Example

[0070] The hydrophobic rearview mirrors prepared in Examples 1 to 6 and Comparative Examples 1 to 3 were respectively subjected to performance detection, and the detection results are shown in Table 12.

[0071] Table 12

[0072]

[0073]

[0074] Among them, the neutral salt mist resistance experiment performance test is based on GB / T32025-2015 aluminum mirror national standard, taking 3 pieces of 100mmx100mm sample, according to the provisions of GB / T 1771 for testing. The pencil hardness experiment is based on GB / T32025-2015 aluminum mirror national standard, taking two pieces of sample according to GB / T 6739-2006 for testing. The neutral pen experiment uses 0.5mm neutral pen core instead of pencil, and is tested according to GB / T 6739-2006.

[0075] Specifically, compared with Comparative Example 1, Example 1 uses a HiPIMS power supply and a ZnSn target to deposit ZnSnO x The water contact angle of the film layer is improved compared with a ZnSnO3 film layer deposited using an MF power supply and a ZnSn target, and the water contact angle of the film layer before and after heat bending is greater than 90°, that is, the hydrophobicity of the film layer is improved; the Cr layer deposited by the HiPIMS technology solves the problem of cracking of the Cr layer in the heat bending process, so that the film layer has no defects after the heat bending process; the Cr and ZnSnO x The SiZrO x The SiO2 is replaced to solve the problem of low surface hardness of the film layer, and the pencil hardness test of the film layer is > 9H, and even no scratches are generated when a neutral pen is used for hardness testing. Compared with the pencil hardness test data 3H of Comparative Example 1, the surface hardness of the film layer is greatly improved, and can resist most scratches in the production and processing process and can resist scratches caused by dust and fine sand in the application process; through reasonable film system design, the film surface reflectivity is 84.6%, and the color is mirror color. Finally, a heat-bendable, high-reflectivity, high-surface-hardness and hydrophobic exterior mirror lens is obtained.

[0076] Compared with Comparative Example 2, Example 2 uses a HiPIMS technology to deposit a Cr layer to solve the problem of cracking of the Cr layer in the heat bending process, so that the film layer has no defects after the heat bending process; the Cr, the ceramic ZTO target replacing the ZnSn target, the SiZrO x The SiO2 is replaced to solve the problem of low surface hardness of the film layer, and the pencil hardness test of the film layer is > 9H, and even no scratches are generated when a neutral pen is used for hardness testing. Compared with the pencil hardness test data 3H of Comparative Example 1, the surface hardness of the film layer is greatly improved, and can resist most scratches in the production and processing process and can resist scratches caused by dust and fine sand in the application process; through reasonable film system design, the film surface reflectivity is 81.5%, and the color is mirror color. Finally, a heat-bendable, high-reflectivity, high-surface-hardness and anti-fingerprint interior mirror lens is obtained.

[0077] Compared with Comparative Example 3, Example 3 uses a HiPIMS power supply and a ZTO target to deposit a ZTO film layer, and the water contact angle of the film layer is improved compared with a SiAlN x The water contact angle of the film layer is improved compared with a ZnSnO3 film layer deposited using an MF power supply and a ZnSn target, and the water contact angle of the film layer before and after heat bending is greater than 90°, that is, the hydrophobicity of the film layer is improved; the Cr layer deposited by the HiPIMS technology solves the problem of cracking of the Cr layer in the heat bending process, so that the film layer has no defects after the heat bending process; the Cr and ZnSnO xThe problem of low surface hardness of the film layer is solved by replacing SiO2, and the pencil hardness test of the film layer is > 9H, and even the hardness test using a neutral pen has no scratches. Compared with the pencil hardness test data 6H of Comparative Example 3, the surface hardness of the film layer is greatly improved, and can resist most scratches during production and processing and can resist scratches caused by dust and fine sand during application; through reasonable film system design, the reflectivity of the film surface is 85.4%, and the color is mirror color. Finally, a heat-bendable, high-reflectivity, high-surface-hardness, fingerprint-resistant interior mirror lens is obtained.

[0078] Example 4 uses a HiPIMS power supply and a ZnSn target to deposit ZnSnO x The water contact angle of the film layer is improved, and the water contact angle of the film layer before and after baking is greater than 90°, improving the hydrophobicity of the film layer; the Cr / CrN layer deposited by the HiPIMS technology is used as the metal layer, and the metal layer is stacked according to CrN-Cr-CrN, which further enhances the bonding force between the metal layer and other film layers during heat bending, so that the film layer has no film layer defects after the heat bending process; the Cr / CrN layer deposited by the HiPIMS technology and the ZnSnO x , SiZrO x plating is used to replace SiO2 to solve the problem of low surface hardness of the film layer, and the pencil hardness test is > 9H, and even the neutral pen hardness test has no scratches; a high (ZnSnO x ) and low (SiZrO x ) refractive layer is deposited on the Cr / CrN layer to enhance blue light reflection and weaken yellow light reflection to achieve the purpose of anti-glare, and the reflectivity of the film surface to blue light (469nm) is 63.5%, which is greater than 60%; the reflectivity to yellow light (570nm) is 34.7%, which is less than 35%, and the overall visible light reflectivity is 41.2%, and the reflectivity is controlled in the best value (40%~43%); the reflectivity of the glass surface is 24.8%, which is blue; finally, a heat-bendable, anti-glare, high-surface-hardness, hydrophobic exterior rearview mirror is obtained.

[0079] Example 5 uses a ZTO target to replace the ZnSn target to deposit a ZTO film layer, and the water contact angle is improved, and the water contact angle of the film layer before and after baking is greater than 90°, improving the hydrophobicity of the film layer; the Cr / CrN layer deposited by the HiPIMS technology is used as the metal layer, and the metal layer is stacked according to CrN-Cr-CrN, which further enhances the bonding force between the metal layer and other film layers during heat bending, so that the film layer has no film layer defects after the heat bending process; the Cr / CrN layer deposited by the HiPIMS technology, the ZTO target replacing the ZnSn target, and the SiZrO xThe replacement of SiO2 solves the problem of low surface hardness of the film layer, and the pencil hardness experiment is > 9H, and even the neutral pen hardness experiment has no scratch; a high (ZTO) and low (SiZrO x ) refractive layer is deposited on the Cr / CrN layer to enhance the blue light reflection and weaken the yellow light reflection to achieve the purpose of anti-glare, the reflectivity of the film surface to blue light (469nm) is 61.7%, which is greater than 60%; the reflectivity to yellow light (570nm) is 37.5%, which is lower than 40%, and the overall visible light reflectivity is 42.7%, and the reflectivity is controlled in the best value (40%-43%); the reflectivity of the glass surface is 35.3%, which is silver gray; the film surface reflectivity curve is shown in Figure 3 , and finally a heat-bendable, anti-glare, high-surface-hardness and hydrophobic exterior rearview mirror is obtained.

[0080] In Example 6, the HiPIMS power supply and ZTO target are used to deposit the ZTO film layer, and the water contact angle is improved, and the water contact angle of the film layer before and after baking is greater than 100°, which improves the hydrophobicity of the film layer; the Cr / CrN layer is deposited by using the HiPIMS technology as the metal layer, and the metal layer is stacked as CrN-Cr-CrN, which further enhances the bonding force between the metal layer and other film layers during heat bending, so that the film layer has no film layer defects after the heat bending process; the Cr / CrN and ZTO are deposited by using the HiPIMS technology, and the SiZrO x The replacement of SiO2 solves the problem of low surface hardness of the film layer, and the pencil hardness experiment is > 9H, and even the neutral pen hardness experiment has no scratch; a high (ZTO) and low (SiZrO x ) refractive layer is deposited on the Cr / CrN layer to enhance the blue light reflection and weaken the yellow light reflection to achieve the purpose of anti-glare, the reflectivity of the film surface to blue light (469nm) is 60.2%, which is greater than 60%; the reflectivity to yellow light (570nm) is 35.9%, which is lower than 40%, and the overall visible light reflectivity is 41.5%, and the reflectivity is controlled in the best value (40%-43%); the reflectivity of the glass surface is 28.3%, which is silver; and finally a heat-bendable, anti-glare, high-surface-hardness and hydrophobic exterior rearview mirror is obtained.

[0081] In summary, the film layer characteristics of ZnSnO x are changed by using the HiPIMS power supply and the ceramic ZTO target, so that the deposited ZnSnO x has a water contact angle greater than 90° as a high-refractive material on the outermost layer of the mirror surface; the HiPIMS technology is used to deposit the Cr / CrN layer to solve the problem of cracking of the heat-bendable Cr / CrN layer; the HiPIMS technology is used to deposit the Cr / CrN and coat the SiZrO x The replacement of SiO2 and the coating of high-hardness ZnSnO xThe ZTO film layer solves the problem of low surface hardness of the film layer, and finally obtains an outer / inner rearview mirror lens which can be hot-bent, has high surface hardness and has hydrophobic and anti-fingerprint functions.

[0082] The above only describes the embodiments of the present application, and does not limit the patent scope of the present application, and any equivalent transformation or direct or indirect application in the related technical field by using the content of the specification and drawings of the present application is also included in the patent protection scope of the present application.

Claims

1. Hydrophobic rearview mirror, characterized in that The hydrophobic rearview mirror comprises at least one dielectric layer, at least one metal layer and at least one reflection-increasing layer formed on a substrate in sequence. wherein the reflection-increasing layer comprises an outer film layer selected from a ZTO film layer magnetron sputter-deposited based on an MF power source or a HiPIMS power source, a ZnSnO film layer magnetron sputter-deposited based on a HiPIMS power source x at least one of the film layers; The ZTO film layer is plated using MF or HiPIMS power supply with target ceramic ZnSnO3, and the ZnSnO3 target is prepared by the following method. x The film layer is plated using HiPIMS power supply with target ZnSn. The reflection-increasing layer further comprises an inner film layer group located inside the outer film layer, the inner film layer group is composed of at least one inner film layer, and the material of the inner film layer is selected from at least one of SiZrO x , SiAlZrO x , SiZrO x N y , SiAlZrO x N y , and SiAlZrO, wherein 1≤x≤3, 1≤y≤3. The inner film layer and the outer film layer form a low / high refractive index film layer stack.

2. The hydrophobic rearview mirror of claim 1, wherein, The thickness of the outer film layer is 25-75 nm, and the refractive index is 1.97-2.

72.

3. The hydrophobic rearview mirror of claim 1, wherein, The metal layer is made of one of chromium metal, chromium alloy, titanium metal, titanium alloy, chromium metal oxide or nitride, and chromium alloy oxide or nitride, and is deposited based on HiPIMS at a peak power of 190-280 kW and a duty cycle of 5%-10%.

4. The hydrophobic rearview mirror of claim 3, wherein, The thickness of the metal layer is 1-90 nm.

5. The hydrophobic rearview mirror according to claim 1, wherein the thickness of the inner film layer is 35-95 nm, and the refractive index of the inner film layer is 1.55-1.

82.

6. The hydrophobic rearview mirror of claim 1, wherein, The material of the medium layer is selected from at least one of AZO, Ti alloy, NbO x , TiO x , NiCr, NiCrO x , ZnAlO x , ZnO x , SnO x , ZnSnO x , SiAlZrN x , SiAlN x , SiN x , SiZrN x , ZTO, ITO, wherein 1≤x≤3, 1≤y≤3.

7. The hydrophobic rearview mirror of claim 6, wherein, The thickness of the dielectric layer is 1-500 nm, and the refractive index of the dielectric layer is 1.58-2.

72.

8. The hydrophobic rearview mirror of claim 1, wherein, The substrate is selected from single-piece flat white glass or colored glass, and the thickness is 0.7-8.0 mm.

9. The method of producing a hydrophobic mirror according to any one of claims 1 to 8, wherein The at least one dielectric layer, the at least one metal layer and the at least one reflection-increasing layer are formed on the substrate in sequence based on a magnetron sputtering process. The dielectric layer is deposited based on MF, DC or HiPIMS power magnetron sputtering. The metal layer is deposited based on HiPIMS power magnetron sputtering.

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