Anti-reflection film

Abstract

A basic film system structure is SUB / HC / (aiHbiL) n / AFm / AIR, i = 1, 2,..., n, n is greater than or equal to 1 and less than or equal to 5, and m = 0 or 1; wherein SUB represents a substrate layer, HC represents a hard coating layer, H represents a high refractive index layer, L represents a low refractive index layer and is selected from an organic material layer, AF represents an antifouling layer, AIR represents air, ai and bi represent coefficients of 1 / 4 wavelength optical thickness respectively, and n and m represent the number of repeated cycles. The low-refractive-index layer is arranged to be the organic material layer, and the physical thickness of the low-refractive-index layer is reasonably set, so that the whole film material has relatively high light transmittance and good anti-bending performance, and the requirement of repeated bending of the flexible display screen is met.

Description

Technical Field

[0001] This application relates to the field of optical thin films, and particularly to an antireflection thin film. Background Art

[0002] The antireflection thin film is a thin film technology used to reduce the reflection of light on the surface of materials. Its main function is to reduce or eliminate the reflected light on the optical surfaces such as lenses, prisms, and plane mirrors, thereby increasing the light transmittance of these components and reducing the stray light of the system. The antireflection thin film is widely used in the field of flexible display screens.

[0003] However, the flexible display screen is prone to creases during the bending process, which not only affects the visual effect but also the user experience; at the same time, the bending of the flexible display screen will cause the antireflection thin film to bend together. The traditional wet antireflection film based on coating has poor abrasion resistance, while the dry antireflection film prepared by the physical method based on inorganic materials has good abrasion resistance, but due to the brittle nature of inorganic materials, it has poor bending resistance. After multiple bends, it will break due to the concentration of bending stress, affecting the use experience of the product. Therefore, the market has put forward high requirements for antireflection thin films with excellent bending resistance and high toughness. Summary of the Utility Model

[0004] To solve the above problems in the prior art, this application provides an antireflection thin film with good bending resistance, which can meet the requirements of flexible display screens that need to be bent repeatedly for many times.

[0005] This application provides an antireflection thin film, and the basic film system structure is: SUB / HC / (a i Hb i L) n / AF m / AIR, i = 1, 2, …, n, 1 ≤ n ≤ 5, m = 0 or 1; where SUB represents the base layer, HC represents the hard coating, H represents the high refractive index layer, L represents the low refractive index layer and is selected from organic material layers, AF represents the antifouling layer, AIR represents air, a i 、b i respectively represent the coefficients of the optical thickness of 1 / 4 wavelength, and n, m represent the number of repeated cycles.

[0006] According to the embodiment of the present utility model, the refractive index of the low refractive index layer is set to be less than the refractive index of the high refractive index layer.

[0007] According to the embodiment of the present utility model, the refractive index of the low refractive index layer is taken from 1.3 - 1.6.

[0008] Preferably, the organic material layer is taken from polytetrafluoroethylene layer, polystyrene resin layer, polyimide resin layer, polycarbonate resin layer, silicone layer, etc.

[0009] According to an embodiment of the present utility model, the physical thickness of the low refractive index layer is taken from 5 - 200 nm.

[0010] According to an embodiment of the present utility model, the refractive index of the high refractive index layer is taken from 1.8 - 2.3.

[0011] According to an embodiment of the present utility model, the high refractive index layer is selected from inorganic material layers.

[0012] Preferably, the high refractive index layer is an oxide layer, nitride layer, oxynitride layer of metals such as Al, Ti, Si, Zr, Ca, Zn, Nb, Ta, and a combined layer of two or more of them.

[0013] According to an embodiment of the present utility model, the physical thickness of the high refractive index layer is taken from 5 - 200 nm.

[0014] According to an embodiment of the present utility model, the base layer is a transparent flexible material layer, and the thickness of the base layer is taken from 20 - 200 μm.

[0015] Specifically, the base layer is a transparent flexible material layer, which can be selected from various transparent flexible substrates well-known to those skilled in the art, and most preferably is a film.

[0016] According to an embodiment of the present utility model, the hard coating is a cured resin layer, and the thickness of the hard coating is taken from 1 - 5 μm.

[0017] Specifically, the hard coating is a photocured resin layer, which can be selected from, for example, epoxy resins, acrylic resins, polyurethane acrylate resins, vinyl ether resins, etc.

[0018] According to an embodiment of the present utility model, the thickness of the anti-fouling layer is taken from 5 - 30 nm.

[0019] Preferably, the thickness of the anti-fouling layer is 20 - 30 nm, and the anti-fouling layer is selected from polymer layers containing at least one of fluorine, fluoroether, methyl, phenyl, and organosilane hydrophobic groups.

[0020] Specifically, in a specific embodiment of the present application, the hard coating is prepared by coating on the base layer, the low refractive index layer and the high refractive index layer are both prepared by magnetron sputtering, and the anti-fouling layer can be prepared by either coating or magnetron sputtering. Further, in a specific embodiment of the present application, a base layer pre-coated with a hard coating is directly purchased.

[0021] The beneficial effects of the present application are as follows: Organic materials are introduced into the low-refractive-index layer, and the physical thickness of the low-refractive-index layer is reasonably set, so that the overall film material has both high light transmittance and good anti-bending performance, meeting the requirements of repeated bending of flexible display screens; the film layer structure is reasonably set. The roughness of the surface of the base layer is leveled through the setting of the hard coating, further improving the light transmittance of the film material. The film material also has hydrophobic and oleophobic properties through the setting of the anti-fouling layer, enhancing the user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present application will be further described in detail below in conjunction with the drawings and preferred embodiments. However, those skilled in the art will understand that these drawings are only drawn for the purpose of explaining the preferred embodiments and should not be construed as limiting the scope of the present application. In addition, unless otherwise specified, the drawings only schematically show the composition or structure of the described object and may include exaggerated displays, and the drawings are not necessarily drawn to scale.

[0023] Figure 1 It is a schematic diagram of the film layer structure of the anti-reflection film disclosed in Embodiment 1 of the present application;

[0024] Figure 2 It is a schematic diagram of the film layer structure of the anti-reflection film disclosed in Embodiment 2 of the present application.

[0025] In the figure: 1, base layer; 2, hard coating; 3, high-refractive-index layer; 4, low-refractive-index layer; 5, anti-fouling layer. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of the described features. In the description of the present invention, "a plurality" means two or more unless otherwise specifically defined.

[0027] In the description of the present utility model, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or a connection that allows mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, and it can be the internal communication between two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0028] In the present utility model, unless otherwise clearly specified and defined, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through additional features therebetween. Moreover, the first feature being "above", "over", and "on top of" the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the first feature has a higher horizontal height than the second feature. The first feature being "below", "beneath", and "underneath" the second feature includes the first feature being directly below and obliquely below the second feature, or merely indicating that the first feature has a lower horizontal height than the second feature.

[0029] The following disclosure provides many different embodiments or examples for implementing different structures of the present utility model. To simplify the disclosure of the present utility model, the components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the present utility model. In addition, the present utility model may repeat reference numerals and / or reference letters in different examples. This repetition is for the purpose of simplification and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present utility model provides examples of various specific processes and materials, but those of ordinary skill in the art may be aware of the application of other processes and / or the use of other materials.

[0030] In the specific embodiment of the present application, an antireflection film is disclosed. The film system structure of the antireflection film is: SUB / HC / (a i Hb i L) n / AF m / AIR, i = 1, 2,..., n, 1 ≤ n ≤ 5, m = 0 or 1; where SUB represents the base layer 1, HC represents the hard coating 2, H represents the high refractive index layer 3, L represents the low refractive index layer 4 and is selected from organic material layers, AF represents the antifouling layer 5, AIR represents air, a i , b i respectively represent the coefficients of the 1 / 4 wavelength optical thickness, and n, m represent the number of repeated periods. The coefficient of the 1 / 4 wavelength optical thickness is calculated by the following formula (1):

[0031]

[0032] Among them, λ is the wavelength, η is the coefficient of the optical thickness of a 1 / 4 wavelength, h is the physical thickness, and r is the refractive index.

[0033] According to formula (1) and the refractive index and physical thickness of the selected film layer material, the coefficient of the optical thickness of a 1 / 4 wavelength of each single layer in the designed low-refractive-index layer 4 and high-refractive-index layer 3 can be calculated.

[0034] For example: when the low-refractive-index layer 4 is a polytetrafluoroethylene layer with a physical thickness of 80 nm and a refractive index of 1.37 at a visible light wavelength of 600 nm, then b can be calculated through formula (1) i is taken as 0.73067; when the high-refractive-index layer 3 is a Nb2O5 layer with a physical thickness of 100 nn and a refractive index of 2.33 at a visible light wavelength of 600 nm, then a can be calculated through formula (1) i is taken as 1.5533.

[0035] Please refer to Figure 1 As shown, in the first embodiment of the present application, a schematic diagram of the film layer structure of an antireflection film is provided. In this antireflection film, m = 0, and at this time the film system structure is: SUB / HC / (a i Hb i L) n / AIR. At this time, the antireflection film does not have an antifouling layer 5.

[0036] The antireflection film described above includes a base layer 1, a hard coating 2, and an antireflection stack layer arranged in sequence from bottom to top. The top of the antireflection stack layer is in contact with air. The antireflection stack layer is formed by alternately stacking multiple high refractive index layers 3 and multiple low refractive index layers 4. The number of alternating stacking cycles is 1 - 5 groups, and most preferably 2 - 3 groups. At this time, the total thickness of the antireflection stack layer is less than 1 μm. While improving the use comfort, it can also ensure that the light transmittance is at least higher than 94%. Specifically, in the antireflection stack layer, the refractive index of the high refractive index layer 3 is taken from 1.8 - 2.3, and the material is selected from inorganic materials well-known to those skilled in the art, including oxides, nitrides, oxynitrides of metals such as Al, Ti, Si, Zr, Ca, Zn, Nb, Ta, and combinations of two or more of them. The most preferred options include any one of SiAlN, AlN, Si3N4, ZrO2, Ta2O3, Ta2O5, TiO2, Nb2O5, SiON, SiAlON, AlON. Selecting inorganic materials for the high refractive index layer 3 can utilize the high hardness characteristics of the inorganic materials themselves, thereby improving the wear resistance and weather resistance of the film material and extending the service life. The refractive index of the low refractive index layer 4 is taken from 1.3 - 1.6, and the material is selected as an organic material, including but not limited to any one of polytetrafluoroethylene, polystyrene resin, polyimide resin, polycarbonate resin, and siloxane. Selecting an organic material for the low refractive index layer 4 can, without affecting the transparency and reflectivity of the film material, utilize the specific molecular chain structure and aggregation mode of the organic material to enhance the toughness and bending resistance of the film material itself, enabling it to better adapt to application scenarios such as folding screens and having a longer service life. Introducing an organic material into the low refractive index layer 4, from a process perspective, the organic low refractive index layer 4 can be prepared by coating a pre-configured coating solution, and can also be prepared by sputtering a solid target of the corresponding material or evaporating the material of the corresponding material, having stronger production efficiency and industrial applicability, and also being beneficial to reducing the production cost of the product. Further, the physical thickness of the low refractive index layer 4 is 5 - 200 nm, and the physical thickness of the high refractive index layer 3 is 5 - 200 nm. According to formula (1), the target antireflection optical wavelength λ, and the refractive index r of the selected material, the coefficients a i and b i can be calculated to complete the optical structure design of the corresponding antireflection stack layer.

[0037] The described base layer 1 is a transparent flexible material layer, and its thickness range is not limited. Those skilled in the art can select a base layer 1 with a suitable thickness according to the actual situation. Most preferably, it is 20 - 200 μm. The transparent flexible material used for the base layer 1 is not limited herein, and commonly used transparent flexible materials in the art can all be used, such as PC film, PTFE film, PET film, PI film, TAC film, etc. The hard coating 2 is a photocurable resin layer, and the thickness can be selected from 1 - 5 μm. The photocurable resin can be selected from epoxy resins, acrylic resins, polyurethane acrylate resins, vinyl ether resins, etc., which is not limited herein. The hard coating 2 is used to level the surface of the substrate, reduce the surface roughness of the base layer 1, and improve the bonding strength and light transmittance with the antireflection stack.

[0038] In terms of process selection, the preparation method of the antireflection film provided in this application is as follows:

[0039] Provide the base layer 1, coat a photocurable resin slurry on the base layer 1 and cure it into the hard coating 2; deposit a high refractive index layer 3 on the hard coating 2 by magnetron sputtering; coat an organic slurry on the high refractive index layer 3 by coating and cure it into a low refractive index layer 4, or deposit a low refractive index layer 4 on the high refractive index layer 3 by magnetron sputtering, or deposit a low refractive evaporation material on the high refractive index layer 3 by evaporation; repeat the preparation process of the aforementioned high refractive index layer 3 and low refractive index layer 4 for 1 - 5 times to obtain a multilayer alternating antireflection stack; the antireflection film is prepared. Preferably, in this application, a base layer 1 pre-coated with a hard coating 2 is directly purchased for use.

[0040] Please refer to Figure 2 As shown, on the basis of Example 1, Example 2 of this application provides a schematic diagram of the film layer structure of its antireflection film. In this antireflection film, m = 1, and at this time, the film system structure is: SUB / HC / (a i Hb i L) n / AF / AIR. In this embodiment, the antireflection film includes a base layer 1, a hard coating 2, an antireflection stack, and an antifouling layer 5 arranged in sequence from bottom to top. The top of the antifouling layer 5 is in contact with air.

[0041] The anti-fouling layer 5 is made of a hydrophobic material, which can prevent water droplets, oil stains, fingerprints, etc. from contaminating the anti-reflection film, and improve the cleanliness of the anti-reflection film during use. In this application, the thickness of the anti-fouling layer 5 ranges from 5 to 30 nm, more preferably 20 to 30 nm, to improve the wear life of the anti-fouling layer 5 while ensuring the coating quality of the anti-fouling layer 5. The anti-fouling layer 5 is a polymer containing at least one of hydrophobic groups such as fluorine, fluoroether, methyl, phenyl, and organosilane; for example, it can be polytetrafluoroethylene, fluorinated polyurethane, fluorinated polyacrylate, polymethyl methacrylate, polydimethylsiloxane, polystyrene, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, methyltrimethoxy(ethoxy)silane, dimethyldimethoxy(ethoxy)silane, trimethylmethoxy(ethoxy)silane, phenyltrimethoxy(ethoxy)silane, perfluorooctyltrichlorosilane, perfluorooctyltrimethoxy(ethoxy)silane, etc. The anti-fouling layer 5 can be prepared on the anti-reflection stack by processes such as evaporation, coating, or chemical vapor deposition in the prior art.

[0042] In the specific embodiments of this application, the materials listed for the high refractive index layer 3 are not limited to the disclosed part. Any material with a refractive index within the disclosed range can be applied to the embodiments of this application; the materials listed for the base layer 1, the hard coating 2, and the anti-fouling layer 5 in the specific embodiments of this application are also not limited to the disclosed part. Any application material well-known to those skilled in the art can be applied to the embodiments in this field.

[0043] The above has introduced this application in detail. Specific examples are used in this article to elaborate on the principle and implementation manner of this application. The description of the above embodiments is only used to help understand this application and its core idea. It should be noted that for those of ordinary skill in the art in this technical field, without departing from the principle of this application, several improvements and modifications can be made to this application, and these improvements and modifications also fall within the protection scope of the claims of this application.

Claims

1. An anti-reflection film, characterized in that: The basic membrane system structure is: SUB / HC / (a i Hb i L) n / AF m / AIR, i=1,2,…,n, 1≤n≤5, m=0 or 1; Wherein, SUB represents a substrate layer (1), HC represents a hard coating layer (2), H represents a high refractive index layer (3), L represents a low refractive index layer (4) selected from an organic material layer, AF represents an antifouling layer (5), AIR represents air, and a i 、b i They represent the coefficients of 1 / 4 wavelength optical thickness, and n and m represent the number of repeated cycles.

2. The anti-reflection film according to claim 1, characterized in that: The refractive index of the low refractive index layer (4) is set to be smaller than the refractive index of the high refractive index layer (3).

3. The anti-reflection film according to claim 2, characterized in that: The refractive index of the low refractive index layer (4) is within the range of 1.3-1.

6.

4. The anti-reflection film according to claim 2, characterized in that: The physical thickness of the low refractive index layer (4) is 5-200 nm.

5. The anti-reflection film according to claim 2, characterized in that: The refractive index of the high refractive index layer (3) is within the range of 1.8-2.

3.

6. The anti-reflection film according to claim 5, characterized in that: The high refractive index layer (3) is selected from inorganic material layers.

7. The anti-reflection film according to claim 2, characterized in that: The physical thickness of the high refractive index layer (3) is 5-200 nm.

8. The anti-reflection film according to claim 1, characterized in that: The base layer (1) is a transparent flexible material layer, and the thickness of the base layer (1) is 20-200 μm.

9. The anti-reflection film according to claim 1, characterized in that: The hard coating layer (2) is a cured resin layer, and the thickness of the hard coating layer (2) is 1-5 μm.

10. The anti-reflection film according to claim 1, characterized in that: The thickness of the antifouling layer (5) is 5-30 nm.

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