Anti-reflection film and preparation method thereof

Abstract

The embodiment of the present application discloses an anti-reflection film and a preparation method thereof, wherein the anti-reflection film comprises a substrate and a microstructure layer, wherein the microstructure layer is arranged on the substrate, the microstructure layer comprises a plurality of microstructures arranged at intervals from each other, and concave holes are arranged between adjacent microstructures, wherein the aperture and depth of the concave holes are in the range of 20nm to 300nm; by setting the aperture and depth of the concave holes to be smaller than the wavelength of light, the light wave cannot recognize the microstructure, so that the refractive index presents a gradient change along the vertical direction of the microstructure, forming a refractive index transition layer, thereby reducing the reflection phenomenon caused by the sharp change of the refractive index, and alleviating the technical problem of low environmental contrast in existing display devices.

Description

Technical Field

[0001] The present application relates to the field of display technology, and in particular to an anti-reflection film and a preparation method thereof. Background Art

[0002] The readability of display panels under ambient light is an important parameter, especially for mobile display devices (such as mobile phones), which are usually used in outdoor environments. The sunlight reflected by the exposed glass cover will seriously wash out the displayed image. In order to quantitatively evaluate the readability under sunlight, the ambient contrast ratio (ACR) is usually used to express it. The calculation method is:

[0003]

[0004] Among them, L1 and L2 are the brightness of the display panel in the bright and dark states respectively, L3 is the ambient light brightness. The outdoor ambient light brightness on a sunny day is about 10000nit, and RL is the surface reflectivity of the display panel. For example, the single-sided reflectivity of glass is about 4%. For an OLED mobile phone with a brightness of 800nit, the native contrast can be as high as 1000000 or more, but when it is in an outdoor sunny environment, the ACR is only 3, which means that the image is severely washed out and cannot be distinguished.

[0005] Therefore, the existing display device has the technical problem of low ambient contrast. Summary of the invention

[0006] The embodiments of the present application provide an anti-reflection film and a method for preparing the same, which can alleviate the technical problem of low ambient contrast in existing display devices.

[0007] The present application provides an anti-reflection film, comprising:

[0008] substrate;

[0009] A microstructure layer, wherein the microstructure layer is disposed on the substrate, the microstructure layer comprises a plurality of microstructures spaced apart from each other, and recessed holes are disposed between adjacent microstructures;

[0010] Wherein, the diameter and depth of the concave hole range from 20nm to 300nm.

[0011] Optionally, in some embodiments of the present application, the absolute value of the difference between the refractive index of the microstructure and the refractive index of the substrate is less than or equal to 0.2.

[0012] Optionally, in some embodiments of the present application, the microstructure includes inorganic particles and refractive index adjusting particles, and the refractive index of the refractive index adjusting particles is equal to the refractive index of the substrate.

[0013] Optionally, in some embodiments of the present application, the particle size range of the inorganic particles and the refractive index adjusting particles is 10 nm to 30 nm.

[0014] Optionally, in some embodiments of the present application, the inorganic particles are at least one of SiO2 particles and nanosilver particles, and the refractive index adjusting particles are at least one of TiO2 nanoparticles and ZrO2 particles.

[0015] Optionally, in some embodiments of the present application, the refractive index of the microstructure layer varies gradiently in a direction perpendicular to the substrate.

[0016] The present invention provides a method for preparing an anti-reflection film, comprising:

[0017] Adding styrene monomer, initiator and emulsifier into the first solvent, stirring to prepare a first dispersion containing polymer microspheres, wherein the particle size of the polymer microspheres ranges from 50 nm to 300 nm;

[0018] Adding tetraethyl silicate to the first dispersion and hydrolyzing it to obtain inorganic particles, thereby forming a second dispersion containing polymer microspheres and inorganic particles;

[0019] providing a substrate;

[0020] The second dispersion is deposited on the substrate surface, the inorganic particles form a plurality of microstructures, the microstructures and the polymer microspheres are spaced apart from each other, and the substrate surface is rinsed with an etching solution to dissolve the polymer microspheres and form concave holes between adjacent microstructures.

[0021] Optionally, in some embodiments of the present application, the step of adding tetraethyl silicate to the first dispersion further includes: adding tetrabutyl titanate to the first dispersion, hydrolyzing to generate TiO2 particles, and preparing refractive index adjusting particles.

[0022] Optionally, in some embodiments of the present application, the etching solution includes at least one of dichloromethane, hydrofluoric acid, and xylene.

[0023] Optionally, in some embodiments of the present application, the ratio of the number of the polymer microspheres to the number of the inorganic particles is in the range of 1:1 to 1:2.

[0024] Beneficial effect: An anti-reflection film is provided, the anti-reflection film includes a microstructure layer, the microstructure layer includes spaced microstructures and concave holes arranged between adjacent microstructures, the aperture and depth of the concave holes range from 20nm to 300nm, because the aperture and depth of the concave holes are smaller than the wavelength of light, the light wave cannot recognize the microstructure, so the refractive index presents a gradient change along the vertical direction of the microstructure to form a refractive index transition layer, thereby reducing the reflection phenomenon caused by the sharp change of the refractive index. The anti-reflection film of the present application can reduce the surface reflectivity, thereby alleviating the technical problem of low ambient contrast in existing display devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 It is a first cross-sectional schematic diagram of the anti-reflection film provided in the present application;

[0027] Figure 2 is a schematic top view of the anti-reflection film provided in the present application;

[0028] Figure 3 is a second cross-sectional schematic diagram of the anti-reflection film provided in the present application;

[0029] Figure 4 is a flow chart of the method for preparing an anti-reflection film provided in the present application;

[0030] FIG. 5A to FIG. 5B is a diagram of the preparation process of the anti-reflection film preparation method provided by the present application;

[0031] Figure 6 It is a schematic diagram showing the variation of the surface reflectivity of the anti-reflection film provided by the present application with the aperture and depth of the concave holes;

[0032] Figure 7 It is a schematic diagram showing that the surface reflectivity of the anti-reflection film provided in the present application varies with the density of the concave holes.

[0033] Description of reference numerals:

[0034] DETAILED DESCRIPTION

[0035] 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 those skilled in the art without creative work are within the scope of protection of the present application. In addition, it should be understood that the specific implementation methods described herein are only used to illustrate and explain the present application, and are not used to limit the present application. In the present application, unless otherwise stated, the directional words such as "upper" and "lower" used generally refer to the upper and lower parts of the device in actual use or working state, specifically the drawing direction in the accompanying drawings; while "inside" and "outside" refer to the outline of the device.

[0036] See also Figure 1 , Figure 2 , Figure 3 The anti-reflection film provided in the present application includes a substrate 10 and a microstructure layer 20, wherein the microstructure layer 20 is arranged on the substrate 10, and the microstructure layer 20 includes a plurality of microstructures 201 arranged at intervals from each other, and concave holes are arranged between adjacent microstructures 201, wherein the aperture S1 and depth S2 of the concave holes range from 20nm to 300nm.

[0037] In this embodiment, since the aperture S1 and depth S2 of the concave hole are both smaller than the wavelength of light, the light wave cannot recognize the microstructure 201, so the refractive index presents a gradient change along the vertical direction of the microstructure 201, forming a refractive index transition layer, thereby reducing the reflection phenomenon caused by the sharp change of the refractive index. The anti-reflection film of the present application can reduce the surface reflectivity, thereby alleviating the technical problem of low ambient contrast in existing display devices.

[0038] The technical solution of the present application is now described in conjunction with specific embodiments.

[0039] In one embodiment, the substrate 10 is made of a transparent glass material or a transparent polymer material.

[0040] The transparent polymer material may be at least one of PET, PMMA, PS and TAC.

[0041] It is understandable that by setting the preparation material of the substrate 10 to be a transparent material, the transmittance of the substrate 10 can be improved. When the anti-reflection film is applied to a display device, the overall transmittance and light output rate of the display device can be improved.

[0042] Furthermore, the anti-reflection film may be a cover plate. For example, when the substrate 10 is made of transparent glass material, the anti-reflection film is a glass cover plate that has the effect of reducing surface reflectivity.

[0043] In this embodiment, the transmittance of the anti-reflection film is improved by setting the preparation material of the substrate 10 to be a transparent material.

[0044] In one embodiment, the absolute value of the difference between the refractive index of the microstructure 201 and the refractive index of the substrate 10 is less than or equal to 0.2.

[0045] The refractive index of the microstructure 201 may be equal to the refractive index of the substrate 10 .

[0046] It can be understood that the smaller the difference in refractive index between the microstructure layer 20 composed of the microstructure 201 and the concave holes and the substrate 10 is, the smaller the reflectivity of the contact surface between the microstructure layer 20 and the substrate 10 is.

[0047] It should be noted that the present embodiment limits the difference between the refractive index of the microstructure 201 and the refractive index of the substrate 10 to be small, that is, the absolute value of the difference between the two is less than or equal to 0.2. In some other embodiments, the absolute value of the difference between the refractive index of the microstructure 201 and the refractive index of the substrate 10 can also be less than or equal to 0.3; as long as the reflectivity of the contact surface between the microstructure layer 20 and the substrate 10 meets the requirements.

[0048] In this embodiment, by further limiting the absolute value of the difference between the refractive index of the microstructure 201 and the refractive index of the substrate 10, the refractive index of the microstructure 201 and the substrate 10 are made nearly equal or equal, thereby reducing the reflectivity of the contact surface between the microstructure layer 20 and the substrate 10.

[0049] In one embodiment, see Figure 3 The microstructure 201 includes inorganic particles 2001 and refractive index adjusting particles 2002 , and the refractive index of the refractive index adjusting particles 2002 is equal to the refractive index of the substrate 10 .

[0050] The refractive index adjusting particles 2002 and the substrate 10 may be made of the same material.

[0051] It can be understood that when there is a difference in the refractive index between the inorganic particles 2001 and the substrate 10 , the refractive index adjusting particles 2002 are used to compensate for the difference so that the refractive index of the microstructure 201 is nearly equal to or equal to the refractive index of the substrate 10 .

[0052] In this embodiment, refractive index adjusting particles 2002 having a refractive index equal to that of the substrate 10 are doped into the microstructure 201 so that the refractive index of the microstructure 201 is close to that of the substrate 10, thereby reducing the refractive index difference between the microstructure 201 and the substrate 10 and reducing the reflectivity at the contact surface between the two.

[0053] For example, in one embodiment, when the refractive index of the inorganic particles 2001 is less than the refractive index of the substrate 10, the refractive index of the refractive index adjusting particles 2002 may be greater than or equal to the refractive index of the substrate 10, thereby making the refractive index of the microstructure 201 tend to be equal to the refractive index of the substrate 10.

[0054] For example, in another embodiment, when the refractive index of the inorganic particles 2001 is greater than the refractive index of the substrate 10, the refractive index of the refractive index adjusting particles 2002 may be less than or equal to the refractive index of the substrate 10, so that the refractive index of the microstructure 201 tends to be equal to the refractive index of the substrate 10.

[0055] It should be noted that the microstructure 201 includes inorganic particles 2001. In some embodiments, the inorganic particles 2001 may also be other materials. The preparation material of the microstructure layer 20 is determined according to the application scenario of the anti-reflection film.

[0056] In one embodiment, the particle sizes of the inorganic particles 2001 and the refractive index adjusting particles 2002 range from 10 nm to 30 nm.

[0057] For example, the particle sizes of the inorganic particles 2001 and the refractive index adjusting particles 2002 may be 10 nm, 20 nm, or 30 nm.

[0058] In one embodiment, the inorganic particles 2001 are at least one of SiO2 particles and nanosilver particles, and the refractive index adjusting particles 2002 are at least one of TiO2 nanoparticles and ZrO2 particles.

[0059] In one embodiment, in a direction perpendicular to the substrate 10 , the refractive index of the microstructure layer 20 changes in a gradient.

[0060] In this embodiment, when the depth S2 and the aperture S1 of the concave hole are both smaller than the wavelength of light, the light wave cannot recognize the microstructure 201, so the refraction of the surface of the microstructure layer 20 material will show a gradient change along the direction perpendicular to the substrate 10, forming a refractive index transition layer, thereby reducing the reflection phenomenon caused by the sharp change of the refractive index, thereby reducing the surface reflectivity of the anti-reflection film.

[0061] See also Figure 4 , Figures 5A to 5B The present invention provides a method for preparing an anti-reflection film, comprising:

[0062] S1: adding styrene monomer, initiator and emulsifier into a first solvent, stirring to prepare a first dispersion liquid containing polymer microspheres 202, wherein the particle size of the polymer microspheres 202 ranges from 50 nm to 300 nm;

[0063] S2: adding tetraethyl silicate to the first dispersion, hydrolyzing to prepare inorganic particles 2001, and forming a second dispersion containing polymer microspheres 202 and inorganic particles 2001;

[0064] S3: providing a substrate 10;

[0065] S4: depositing the second dispersion on the surface of the substrate 10, the inorganic particles 2001 forming a plurality of microstructures 201, the microstructures 201 and the polymer microspheres 202 being spaced apart from each other, and washing the surface of the substrate 10 with an etching solution to dissolve the polymer microspheres 202, thereby forming concave holes between adjacent microstructures 201.

[0066] The step of stirring to prepare the first dispersion liquid containing the polymer microspheres 202 further comprises: stirring in a heating environment at 60° C.

[0067] Wherein, the first solvent may be water.

[0068] It can be understood that by setting the polymer microspheres 202 with a particle size range of 50nm to 300nm, adjacent microstructures 201 are separated by the polymer microspheres 202, and the polymer microspheres 202 are etched and removed to form concave holes at the polymer microspheres 202, and the depth S2 and the aperture S1 of the concave holes are in the range of 20nm to 300nm, and the depth S2 and the aperture S1 of the concave holes are both smaller than the wavelength of light, thereby reducing the surface reflectivity of the anti-reflection film.

[0069] In this embodiment, a first dispersion liquid and a second dispersion liquid are first prepared, and a microstructure layer is formed by a coating and etching method. The microstructure layer plays a role of refractive index transition, which can effectively reduce the surface reflectivity and has the advantages of simple process, high efficiency and low cost. It is widely applicable and can be used in display, decoration, construction and other scenes.

[0070] See also Figure 6 The substrate 10 is a glass material with a smooth surface, a refractive index of about 1.5, and a surface reflectivity of 3.1%; when the particle size of the polymer microspheres 202 is 100nm, 150nm, 200nm and 300nm, the surface reflectivity of the anti-reflection film is reduced to 2.34%, 1.72%, 0.98% and 0.27% respectively.

[0071] It can be understood that the particle size of the polymer microspheres 202 is in the range of 50 nm to 300 nm. The larger the particle size of the polymer microspheres 202 is, the larger the aperture S1 and depth S2 of the concave holes are, and the lower the surface reflectivity of the anti-reflection film is.

[0072] Preferably, the particle size of the polymer microspheres 202 may be greater than 200 nm, so that the surface reflectivity of the anti-reflection film is less than 0.98%, which greatly reduces the surface reflectivity compared to the surface reflectivity of 3.1%.

[0073] In this embodiment, the surface reflectivity of the anti-reflection film is further reduced by increasing the aperture S1 and the depth S2 of the concave hole.

[0074] In some other embodiments, when the aperture S1 and depth S2 of the concave hole are greater than 300nm, for example, when the aperture S1 and depth S2 of the concave hole are in the range of 300nm to 500nm, the reflectivity is still reduced compared with that before improvement, that is, when the substrate 10 is a glass material with a smooth surface, its refractive index is about 1.5, and its surface reflectivity is 3.1%, when the aperture S1 and depth S2 of the concave hole are in the range of 300nm to 500nm, the surface reflectivity after improvement is less than 3.1%.

[0075] See also Figure 7 In one embodiment, when the content ratio of polymer microspheres 202 to inorganic particles 2001 is reduced from 1 to 0.75 and 0.5, the surface reflectivity changes from 1.28% to 0.78% and 1.64%.

[0076] Preferably, the content ratio of the polymer microspheres 202 to the inorganic particles 2001 is less than 0.75.

[0077] It is understandable that when the content of the polymer microspheres 202 decreases, the density of the formed concave holes decreases, and the density of the concave holes will also affect the surface reflectivity.

[0078] It should be noted that the content ratio of the polymer microspheres 202 to the inorganic particles 2001 refers to the quantitative ratio of the two.

[0079] In one embodiment, the polymer microspheres 202 may be at least one of PMMA nanoparticles and polystyrene nanoparticles.

[0080] In one embodiment, the step of adding tetraethyl silicate to the first dispersion further includes: adding tetrabutyl titanate to the first dispersion, hydrolyzing to generate TiO 2 particles, and preparing the refractive index adjusting particles 2002 .

[0081] In one embodiment, the etching solution includes at least one of dichloromethane, hydrofluoric acid, and xylene.

[0082] For example, in one embodiment, the polymer microspheres 202 are 100 nm polystyrene nanoparticles, the inorganic particles B are 30 nm SiO2 particles, and the refractive index adjusting particles 2002 are 20 nm TiO2 nanoparticles. At this time, the etching solution is dichloromethane.

[0083] For example, in one embodiment, the polymer microspheres 202 are 50 nm PMMA nanoparticles, the inorganic particles B are 30 nm SiO2 particles, and the refractive index adjusting particles 2002 are 20 nm TiO2 nanoparticles. At this time, the etching solution is hydrofluoric acid.

[0084] For example, in another embodiment, the polymer microspheres 202 are 300 nm polystyrene nanoparticles, the inorganic particles B are 20 nm silver particles, the refractive index adjusting particles 2002 are 20 nm ZrO2 particles, and the etching solution is xylene.

[0085] In one embodiment, the ratio of the number of the polymer microspheres 202 to the number of the inorganic particles 2001 is in a range of 1:1 to 1:2.

[0086] In one embodiment, the preparation material of the microstructure layer 20 includes at least one of acrylic resin, epoxy resin, Hardcoating, Au, Ag, ZnO, TiO2 nanoparticles, SiO2 particles, silicate, PS particles, and PMMA particles.

[0087] The present application also proposes a display device, which includes the above-mentioned anti-reflection film, which will not be described in detail here.

[0088] The anti-reflection film provided in the present application includes a substrate and a microstructure layer, wherein the microstructure layer is arranged on the substrate, and the microstructure layer includes a plurality of microstructures arranged at intervals from each other, and concave holes are arranged between adjacent microstructures, wherein the aperture and depth of the concave holes are in the range of 20nm to 300nm; since the aperture and depth of the concave holes are smaller than the wavelength of light, the light wave cannot recognize the microstructure, so the refractive index presents a gradient change along the vertical direction of the microstructure to form a refractive index transition layer, thereby reducing the reflection phenomenon caused by the sharp change of the refractive index. The anti-reflection film of the present application can reduce the surface reflectivity, thereby alleviating the technical problem of low environmental contrast in existing display devices.

[0089] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0090] The anti-reflection film and the method for preparing the anti-reflection film provided in the embodiments of the present application are introduced in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present application, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A method for preparing an anti-reflection film, characterized in that: include: Adding styrene monomer, initiator and emulsifier into the first solvent, stirring to prepare a first dispersion containing polymer microspheres, wherein the particle size of the polymer microspheres ranges from 50 nm to 300 nm; Adding tetraethyl silicate to the first dispersion, hydrolyzing to prepare inorganic particles, and forming a second dispersion containing polymer microspheres and inorganic particles, wherein the content ratio of the polymer microspheres to the inorganic particles is 0.75; providing a substrate; The second dispersion is deposited on the surface of the substrate, the inorganic particles form a plurality of microstructures, the microstructures and the polymer microspheres are spaced apart from each other, the substrate surface is rinsed with an etching solution to dissolve the polymer microspheres, and concave holes are formed between adjacent microstructures to prepare an anti-reflection film, the surface reflectivity of the anti-reflection film is 0.78%, and the microstructures include inorganic particles and refractive index adjusting particles.

2. The method for preparing an anti-reflection film according to claim 1, characterized in that: The step of adding tetraethyl silicate to the first dispersion also includes: adding tetrabutyl titanate to the first dispersion, hydrolyzing to generate TiO2 particles, and preparing the refractive index adjusting particles.

3. The method for preparing an anti-reflection film according to claim 1, characterized in that: The etching solution includes at least one of dichloromethane, hydrofluoric acid and xylene.

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