Impact-resistant hardened film and preparation method thereof

Abstract

The invention discloses an anti-impact hardened film and a preparation method thereof.The anti-impact hardened film comprises a plurality of first film layers, second film layers and third film layers which are alternately stacked, the first film layers are high-refractive-index film layers, the second film layers and the third film layers are low-refractive-index film layers with the refractive index smaller than that of the high-refractive-index film layers, and the third film layers are low-refractive-index film layers with the refractive index smaller than that of the high-refractive-index film layers. The outermost layer of the impact-resistant hardened film is a first film layer and a third film layer, the secondary outer layer of the impact-resistant hardened film is a second film layer, and according to the preparation method of the impact-resistant hardened film, the hardness and stress of the film layers are increased by controlling the filling flow of reaction gas and the sputtering power of a target material; meanwhile, the hydrophobicity of the film layer and good anti-reflection performance in a visible light region can be ensured, and the film layer has a wide application prospect in the field of screen protection of vehicle-mounted and mobile equipment.

Description

Technical Field

[0001] The invention belongs to the technical field of optical films, and in particular relates to an impact-resistant hardened film and a preparation method thereof. Background Art

[0002] With the development of assisted driving or autonomous driving, higher requirements are also placed on in-vehicle imaging. The G1 lens of an in-vehicle camera is usually the lens exposed on the outside. When used outdoors or in harsh environments, such as when impacted by wind, sand, dust, and stones, the surface of the traditional lens will be worn, scratched, or cracked, resulting in insufficient clarity or aggravated ghost images, which seriously affects the service life of the in-vehicle camera and the safety of in-vehicle assisted driving. Therefore, it is an urgent need in the current market to propose a hardened film with high hardness, good optical properties, and friction resistance. Summary of the invention

[0003] The purpose of the present invention is to address the above problems and to propose an impact-resistant hardened film and a preparation method thereof, which not only has a high hardness to effectively prevent wear, scratches or cracks, but also helps to ensure good optical properties and surface hydrophobicity.

[0004] To achieve the above object, the technical solution adopted by the present invention is:

[0005] The present invention proposes an impact-resistant hardened film, comprising a plurality of alternately stacked first film layers, second film layers and third film layers, wherein the first film layer is a high-refractive index film layer, the second film layer and the third film layer are both low-refractive index film layers whose refractive index is lower than that of the high-refractive index film layer, and the outermost layers of the impact-resistant hardened film are respectively the first film layer and the third film layer, and the next outermost layers are both the second film layer, and the total thickness of the impact-resistant hardened film is 500nm to 1000nm.

[0006] Preferably, the thickness of the first film layer is 12 nm to 200 nm, the thickness of the second film layer is 12 nm to 150 nm, and the thickness of the third film layer is 5 nm to 20 nm.

[0007] Preferably, the refractive index of the first film layer is 1.95-2.10, and the refractive index of the second film layer and the third film layer are both 1.45-1.50.

[0008] Preferably, the total number of the first film layer, the second film layer and the third film layer is 10 to 50 layers.

[0009] Preferably, the first film layer is a silicon nitride layer, the second film layer is a silicon oxynitride layer, and the third film layer is a hydrophobic film.

[0010] Preferably, the first film layer accounts for 20%-80% of the thickness of the impact-resistant hardened film.

[0011] Preferably, the impact-resistant hardened film further comprises a substrate, which is attached to the outermost first film layer and arranged opposite to the third film layer.

[0012] Preferably, the substrate is a glass substrate or a plastic substrate, and the first surface of the substrate is a convex surface. The glass substrate is a crown optical glass substrate or a lanthanide optical glass substrate or a barium optical glass substrate, and the plastic substrate is a PMMA substrate or a PC substrate.

[0013] A method for preparing an impact-resistant hard film comprises the following steps:

[0014] S1. Pre-treat the optical substrate and then install it on the sample rack of the vacuum coating device;

[0015] S2. Install a silicon target with a purity of 4N or 5N on a target holder of a vacuum coating device;

[0016] S3, evacuate the vacuum chamber of the vacuum coating device to 4.0E-4Pa-8.0E-4Pa and maintain the temperature at 120°C-320°C;

[0017] S4, filling the vacuum chamber of the vacuum coating device with reaction gas, alternately laminating the first film layer and the second film layer of the impact-resistant hard film on the first surface of the optical substrate, the reaction gas is one or more of oxygen, nitrogen, and argon, and the silicon target is sputtered by argon, the oxygen filling flow rate is 200-300sccm, the nitrogen filling flow rate is 0-50sccm, and the argon filling flow rate is 40-120sccm, and the sputtering power of the first film layer and the second film layer is 2-10KW;

[0018] S5, deflate the vacuum chamber of the vacuum coating device and take out the semi-finished product;

[0019] S6. Depositing a third film layer on the outermost film layer on the first surface of the semi-finished product away from the optical substrate to obtain an impact-resistant hardened film.

[0020] Preferably, the pretreatment is to perform ultrasonic cleaning and plasma cleaning in sequence; the first film layer and the second film layer of the impact-resistant hardened film are alternately stacked on the first surface of the optical substrate, and when the first film layer is plated, the reaction gases filled in are nitrogen and argon, and when the second film layer is plated, the reaction gases filled in are oxygen, nitrogen and argon.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present application has high transmittance in the visible light region, can effectively resist stone impact and scratches, has high hardness, good hydrophobicity and excellent scratch resistance, and has a long service life; and in the coating process, by controlling the charging flow of the reaction gas and the sputtering power of the target material to increase the hardness and stress of the film layer, while maintaining the hardness and having a smaller stress, preventing the film from cracking after being placed for a period of time, and at the same time can ensure the hydrophobicity of the film layer and good anti-reflection performance in the visible light region, and has broad application prospects in the field of screen protection for vehicles and mobile devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic structural diagram of an impact-resistant hard film (without a substrate) according to Example 1 of the present invention;

[0024] Figure 2 This is a schematic structural diagram of an impact-resistant hard film (including a substrate) according to Example 1 of the present invention;

[0025] Figure 3 This is a flow chart of a method for preparing an impact-resistant hard film according to Example 2 of the present invention;

[0026] Figure 4 This is a graph showing the wear test results of different impact-resistant hardened films (including substrates) using an 8H test pencil in the present invention;

[0027] Figure 5 This is a graph showing the test results of the drip angle of different impact-resistant hardened films (including substrates) using an 8H test pencil in the present invention;

[0028] Figure 6 This is a graph showing the wear test results of different impact-resistant hardened films (including substrates) using a 9H test pencil in the present invention;

[0029] Figure 7 This is a graph showing the test results of the drip angle of different impact-resistant hardened films (including substrates) using a 9H test pencil in the present invention;

[0030] Figure 8 This is a test result diagram of the drip angle of different impact-resistant hardened films (including substrates) using a bristle brush with a load of 20N in the present invention;

[0031] Fig. 9 The spectral curve diagram of the reflectivity of the impact-resistant hard film (without substrate) of the present invention between wavelengths of 400nm-700nm.

[0032] Explanation of the accompanying drawings: 1. first film layer; 2. second film layer; 3. third film layer; 4. substrate. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0034] It should be noted that, unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art in the technical field of this application. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0035] Embodiment 1:

[0036] like Figure 1 As shown, an impact-resistant hardened film comprises a plurality of alternately stacked first film layers 1, second film layers 2 and third film layers 3, wherein the first film layer 1 is a high refractive index film layer, the second film layer 2 and the third film layer 3 are both low refractive index film layers having a refractive index lower than that of the high refractive index film layer, and the outermost layers of the impact-resistant hardened film are the first film layer 1 and the third film layer 3 respectively, and the next outermost layers are the second film layer 2, and the total thickness of the impact-resistant hardened film is 500nm to 1000nm.

[0037] Among them, the first film layer 1 and the second film layer 2 are the main hardening components, and the third film layer 3 plays the role of lubrication, reducing friction coefficient, and anti-fingerprint. The impact-resistant hardened film can increase the impact resistance and service life, and has good anti-reflection performance in the visible light region. It meets the requirements of no scratches on the surface after 500 8H and 100 9H pencil scratch tests under a load of 1000g / cm2, and the drip angle is greater than 100°, showing high hardness while ensuring hydrophobicity. It is suitable for applications such as automotive and mobile device displays that require high hardness, wear resistance and hydrophobicity.

[0038] In one embodiment, the thickness of the first film layer 1 is 12nm-200nm, the thickness of the second film layer 2 is 12nm-150nm, and the thickness of the third film layer 3 is 5nm-20nm. It can maintain excellent spectral characteristics, effectively reduce reflectivity, increase transmittance, and maintain excellent hardening effect.

[0039] In one embodiment, the refractive index of the first film layer 1 is 1.95-2.10, and the refractive indexes of the second film layer 2 and the third film layer 3 are both 1.45-1.50. Among them, when the refractive index of the first film layer 1 is 1.95-2.10, if the first film layer 1 is a silicon oxynitride layer, the nitridation effect is good and the hardness is excellent. The hardness value of the silicon oxynitride layer obtained after nitridation of silicon oxide will also be improved, and the refractive index will be greater than the refractive index of silicon oxide.

[0040] In one embodiment, the total number of layers of the first film layer 1, the second film layer 2 and the third film layer 3 is 10 to 50. The total number of layers is 10 to 50, which can achieve both manufacturing cost and anti-reflection effect.

[0041] In one embodiment, the first film layer 1 is a silicon nitride layer, the second film layer 2 is a silicon oxynitride layer, and the third film layer 3 is a hydrophobic film. The above materials can effectively reduce the reflectivity, maintain an excellent hardening effect, and also have an anti-fingerprint effect.

[0042] In one embodiment, the first film layer 1 accounts for 20%-80% of the thickness of the impact-resistant hardened film. The higher the thickness ratio of the first film layer 1, the more obvious the hardening effect of the film layer. If the thickness ratio exceeds this range and further increases, it is difficult to meet the requirements of the optical film curve.

[0043] In one embodiment, the impact-resistant hard film further comprises a substrate 4, which is attached to the outermost first film layer 1 and arranged opposite to the third film layer 3. Figure 2 As shown, the substrate 4 is generally an optical lens, a screen, etc., or can be adjusted according to actual needs.

[0044] In one embodiment, the substrate 4 is a glass substrate or a plastic substrate, and the first surface of the substrate 4 is a convex surface, the glass substrate is a crown optical glass substrate, a lanthanum optical glass substrate, or a barium optical glass substrate, and the plastic substrate is a PMMA substrate or a PC substrate. It is easy to understand that the specific materials of the glass substrate and the plastic substrate can also be adjusted according to actual needs, such as other materials commonly used by those skilled in the art.

[0045] Embodiment 2:

[0046] like Figure 3 As shown, based on Example 1, a method for preparing an impact-resistant hardened film comprises the following steps:

[0047] S1. Pre-treat the optical substrate and then install it on the sample rack of the vacuum coating device;

[0048] S2. Install a silicon target with a purity of 4N or 5N on a target holder of a vacuum coating device;

[0049] S3, evacuate the vacuum chamber of the vacuum coating device to 4.0E-4Pa-8.0E-4Pa and maintain the temperature at 120°C-320°C;

[0050] S4, filling the vacuum chamber of the vacuum coating device with reaction gas, alternately laminating the first film layer 1 and the second film layer 2 of the impact-resistant hard film on the first surface of the optical substrate, the reaction gas is one or more of oxygen, nitrogen, and argon, and the silicon target is sputtered by argon, the oxygen filling flow rate is 200-300sccm, the nitrogen filling flow rate is 0-50sccm, and the argon filling flow rate is 40-120sccm, and the sputtering power of the first film layer 1 and the second film layer 2 are both 2-10KW;

[0051] S5, deflate the vacuum chamber of the vacuum coating device and take out the semi-finished product;

[0052] S6. Depositing a third film layer 3 on the outermost film layer of the first surface away from the optical substrate on the semi-finished product to obtain an impact-resistant hardened film.

[0053] Among them, the optical substrate can be a carrier for preparing an impact-resistant hard film, or directly a substrate 4. Each film layer is prepared by physical vapor deposition technology using the principles of optical reflection, absorption and refraction. For example, the first film layer 1 can be formed by magnetron sputtering a silicon target by a physical vapor deposition method to form a single silicon film layer and then oxidized; the second film layer 2 is formed by magnetron sputtering a silicon target by a physical vapor deposition method and then nitrided; the third film layer 3 is formed by a physical vapor deposition method using an electron gun or a vapor barrier to evaporate a hydrophobic material. The first film layer 1 and the second film layer 2 are prepared by the same device, and the third film layer 3 is prepared by another device. The coating method of the vacuum coating device is one of ion beam sputtering vacuum coating and magnetron sputtering vacuum coating, or other coating methods well known to those skilled in the art can also be used, such as ion-assisted deposition evaporation vacuum coating. The magnetron sputtering method is used to control the charging flow of the reaction gas and the sputtering power of the target material to increase the hardness and stress of the impact-resistant hardened film, so that it can take into account both advantages, namely hardness and stress. While maintaining the hardness, it also has a smaller stress to prevent film cracking after being placed for a period of time.

[0054] In one embodiment, the pretreatment is to perform ultrasonic cleaning and plasma cleaning in sequence; the first film layer and the second film layer of the impact-resistant hardened film are alternately stacked on the first surface of the optical substrate, and when the first film layer is plated, the reaction gases filled in are nitrogen and argon, and when the second film layer is plated, the reaction gases filled in are oxygen, nitrogen and argon.

[0055] In this embodiment, the vacuum coating device adopts the Guangchi NSC-15 model, and the coating method of the vacuum coating device adopts the magnetron sputtering method. The first surface of the substrate is convex, and the material is H-ZLAF50E optical glass. Silicon oxide-nitride (silicon oxynitride) is prepared as a low refractive index film layer, and silicon-nitride (silicon nitride) is prepared as a high refractive index film layer. The two film layers are stacked in sequence to form an impact-resistant hard film.

[0056] The preparation process is as follows:

[0057] 1) After ultrasonic cleaning and plasma cleaning, the substrate 4 (optical substrate) is mounted on a sample holder of a vacuum coating device to ensure the cleanliness and flatness of the substrate surface;

[0058] 2) Installing a 5N purity silicon target on a target holder of a magnetron sputtering vacuum coating device;

[0059] 3) Pump the vacuum chamber to 6.0E-4Pa and maintain the temperature at 150°C;

[0060] 4) Fill the vacuum chamber of the vacuum coating device with reactive gas, and alternately laminate the first film layer and the second film layer of the impact-resistant hard film on the first surface of the substrate 4. The low refractive index film layer is a silicon nitride layer filled with nitrogen, oxygen and argon at different flow rates, and the high refractive index film layer is a silicon nitride layer filled with nitrogen and argon at different flow rates. When plating the silicon nitride layer, the oxygen filling flow rate is 280sccm, the nitrogen filling flow rate is 20sccm, the argon filling flow rate is 80sccm, and the sputtering power is 8KW; when plating the silicon nitride layer, the nitrogen filling flow rate is 300sccm, the argon filling flow rate is 80sccm, and the sputtering power is 8KW. The sputtered atoms or molecules are ionized in the vacuum chamber to form a high-energy ion beam, which is deposited on the surface of the substrate 4, and the silicon nitride layer and the silicon oxide layer are laminated in sequence;

[0061] 5) Deflate the vacuum chamber of the vacuum coating device and take out the semi-finished product;

[0062] 6) Depositing a third film layer 3 on the outermost film layer of the first surface of the semi-finished product away from the substrate to obtain an impact-resistant hardened film.

[0063] For the above-mentioned Example 1 and Example 2, the impact-resistant hardened film is as shown in Table 1, wherein the thickness ratio of the first film layer 1 accounts for 59.13% of the impact-resistant hardened film.

[0064] Table 1

[0065] Material Silicon Nitride Silicon Oxynitride Silicon Nitride Silicon Oxynitride Silicon Nitride Silicon Oxynitride Film First film layer Second film layer First film layer Second film layer First film layer Second film layer Thickness / nm 21.48 13.65 165.95 19.89 50.97 15.32 Material Silicon Nitride Silicon Oxynitride Silicon Nitride Silicon Oxynitride Silicon Nitride Silicon Oxynitride Film First film layer Second film layer First film layer Second film layer First film layer Second film layer Thickness / nm 93.8 29.77 21.49 111.17 25.31 24.84 Material Silicon Nitride Silicon Oxynitride Hydrophobic materials Film First film layer Second film layer The third film Thickness / nm 73.37 88.03 10

[0066] To further verify the advantages of this application, performance tests were conducted:

[0067] During the test, a test pencil is used to perform a wear test on the impact-resistant hard film containing an optical substrate (i.e., substrate 4, in this embodiment, substrate 4 is a lens), and a pig bristle brush is used to perform a drip angle test. Figure 4-Figure 8As shown. The exposed length of the pencil lead of the test pencil is about 3mm to prevent breakage during the test. The angle between the test pencil and the impact-resistant hardened film (including the substrate) (the first lens on the vehicle, i.e. the exposed lens) is 90°. The specific degree can be adjusted according to actual needs. The contact surface is smooth (the head of the pencil lead is ground and contacts the outer side, i.e. the convex surface, of the impact-resistant hardened film). During the test sliding process, the pencil lead cannot exceed the effective diameter of the impact-resistant hardened film. The test speed is 60 back and forth / min. The test pencil is Mitsubishi 8H / 9H, and a 20X microscope is used to observe the test results.

[0068] 1) Use an 8H test pencil to apply a force of 1000g / cm2, scratch back and forth 500 times at the same position of the impact-resistant hard film, use 2 pieces of impact-resistant hard film for each test, no scratches on the surface, the test results are as follows Figure 4 As shown, the drip angle is ≥100°, and the test results are as follows Figure 5 shown.

[0069] 2) Use a 9H test pencil to apply a force of 1000g / cm2, scratch the same position of the impact-resistant hard film 100 times, and there is no scratch on the surface. Use 2 pieces of impact-resistant hard film for each test. The test results are as follows: Figure 6 As shown, the drip angle is ≥100°, and the test results are as follows Figure 7 shown.

[0070] 3) Use a bristle brush with a load of 20N, and use 2 pieces of impact-resistant hardened films for the test each time. Scratch back and forth 500 times at the same position of the impact-resistant hardened film, with a drip angle of ≥100°. The test results are as follows: Figure 8 shown.

[0071] 4) Optical spectrometry requires 400nm-420nm, Rmax (maximum reflectivity) ≤ 1.0%, and the spectroscopic curve test results are as follows Fig. 9 shown.

[0072] This application adopts vacuum coating technology to prepare impact-resistant hardened film, using silicon target with purity of 4N or 5N as target material. During the coating process, the hardness of the film layer is increased by controlling the injection flow rate of the reaction gas, which helps to ensure the hydrophobicity of the film layer and good anti-reflection performance in the visible light region. It is suitable for application fields such as automotive and mobile device displays that require high hardness, wear resistance and hydrophobicity.

[0073] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0074] The above-described embodiments only express the more specific and detailed embodiments described in this application, but they cannot be understood as limiting the scope of the patent application. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of this application, which all belong to the protection scope of this application. Therefore, the protection scope of the patent application shall be based on the attached claims.

Claims

1. An impact-resistant hard film, characterized in that: The impact-resistant hardened film comprises a plurality of alternately stacked first film layers (1), second film layers (2) and third film layers (3), wherein the first film layer (1) is a high refractive index film layer, the second film layer (2) and the third film layer (3) are both low refractive index film layers having a refractive index lower than that of the high refractive index film layer, and the outermost layers of the impact-resistant hardened film are the first film layer (1) and the third film layer (3), respectively, and the next outermost layers are the second film layer (2), and the total thickness of the impact-resistant hardened film is 500nm to 1000nm.

2. The impact-resistant hardened film according to claim 1, characterized in that: The thickness of the first film layer (1) is 12nm to 200nm, the thickness of the second film layer (2) is 12nm to 150nm, and the thickness of the third film layer (3) is 5nm to 20nm.

3. The impact-resistant hardened film according to claim 1, characterized in that: The refractive index of the first film layer (1) is 1.95 to 2.10, and the refractive index of the second film layer (2) and the third film layer (3) are both 1.45 to 1.

50.

4. The impact-resistant hardened film according to claim 1, characterized in that: The total number of layers of the first film layer (1), the second film layer (2) and the third film layer (3) is 10 to 50 layers.

5. The impact-resistant hardened film according to claim 1, characterized in that: The first film layer (1) is a silicon nitride layer, the second film layer (2) is a silicon oxynitride layer, and the third film layer (3) is a hydrophobic film.

6. The impact-resistant hardened film according to claim 1, characterized in that: The first film layer (1) accounts for 20%-80% of the thickness of the impact-resistant hardened film.

7. The impact-resistant hardened film according to claim 1, characterized in that: The impact-resistant hardened film further comprises a substrate (4), wherein the substrate (4) is attached to the outermost first film layer (1) and is arranged opposite to the third film layer (3).

8. The impact-resistant hardened film according to claim 7, characterized in that: The substrate (4) is a glass substrate or a plastic substrate, and the first surface of the substrate (4) is a convex surface. The glass substrate is a crown optical glass substrate, a lanthanide optical glass substrate, or a barium optical glass substrate. The plastic substrate is a PMMA substrate or a PC substrate.

9. A method for preparing an impact-resistant hard film, characterized in that: The method for preparing the impact-resistant hardened film comprises the following steps: S1. Pre-treat the optical substrate and then install it on the sample rack of the vacuum coating device; S2. Install a silicon target with a purity of 4N or 5N on a target holder of a vacuum coating device; S3, evacuate the vacuum chamber of the vacuum coating device to 4.0E-4Pa-8.0E-4Pa and maintain the temperature at 120°C-320°C; S4, filling the vacuum chamber of the vacuum coating device with reaction gas, and alternately stacking the first film layer (1) and the second film layer (2) of the impact-resistant hardened film according to any one of claims 1 to 8 on the first surface of the optical substrate, wherein the reaction gas is one or more of oxygen, nitrogen, and argon, and the silicon target is sputtered by the argon gas, the oxygen filling flow rate is 200 to 300 sccm, the nitrogen filling flow rate is 0 to 50 sccm, and the argon filling flow rate is 40 to 120 sccm, and the sputtering power of the first film layer (1) and the second film layer (2) are both 2 to 10 kW; S5, deflate the vacuum chamber of the vacuum coating device and take out the semi-finished product; S6. Depositing the third film layer (3) on the outermost film layer on the first surface of the semi-finished product away from the optical substrate to obtain an impact-resistant hardened film.

10. The method for preparing the impact-resistant hardened film according to claim 9, characterized in that: The pretreatment is ultrasonic cleaning and plasma cleaning in sequence; the first film layer (1) and the second film layer (2) of the impact-resistant hardened film as described in any one of claims 1 to 8 are alternately layered on the first surface of the optical substrate, and when the first film layer (1) is plated, the reaction gases filled are nitrogen and argon, and when the second film layer (2) is plated, the reaction gases filled are oxygen, nitrogen and argon.

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