A high-increment wide-view angle brightness enhancement film and a backlight module

Abstract

This application discloses a high-increase, wide-viewing-angle brightness enhancement film and a backlight module. The brightness enhancement film includes a film layer with a first surface; a plurality of first protrusions arranged along a first direction on the first surface, the first protrusions extending along a second direction, and the surface of the first protrusions facing away from the first film layer including a first side surface and a second side surface on both sides, and a diffusion surface located between the first side surface and the second side surface; a plurality of second protrusions uniformly arranged on the first side surface and the second side surface of the first protrusions, the second protrusions being used to guide internal and external light to the diffusion surface. This application can effectively improve light utilization and increase the viewing angle.

Description

Technical Field

[0001] This application belongs to the field of display technology, specifically relating to a high-increase, wide-viewing-angle brightness enhancement film and a backlight module. Background Technology

[0002] Brightness enhancement film is one of the most important optical films widely used in the backlight module of LCD displays. Its main function is to concentrate light emitted from all directions from the light source towards the front, thereby improving light utilization, reducing light loss, and achieving the purpose of increasing backlight brightness or reducing power consumption.

[0003] In pursuit of thinner designs, large-size LCD products currently primarily utilize edge-lit backlight module systems, employing LED strips for illumination. With the same number of LED strips, a larger module size results in a relative decrease in brightness, necessitating higher light source utilization. Simultaneously, as LCD product sizes increase, a wider viewing angle is required within the backlight module architecture to ensure a consistent brightness level from different angles. Existing brightness enhancement films cannot meet the growing demands for higher light source utilization and wider viewing angles in large-size LCD products. Summary of the Invention

[0004] The purpose of this application is to provide a high-increase, wide-viewing-angle brightness enhancement film and backlight module to solve the technical problem that existing brightness enhancement films cannot meet the increasing demands for light source utilization and wide viewing angles in large-size LCD products.

[0005] To achieve the above objectives, one technical solution adopted in this application is to provide a high-increase, wide-viewing-angle brightening film, comprising:

[0006] The film layer, including the first surface,

[0007] A plurality of first protrusions are arranged along a first direction on the first surface, the first protrusions extend along a second direction, and the surface of the first protrusions facing away from the first film layer includes a first side surface and a second side surface located on both sides and a diffusion surface located between the first side surface and the second side surface.

[0008] Several second protrusions are evenly arranged on the first side and the second side of the first protrusion, and the second protrusions are used to guide internal light and external light to the diffusion surface.

[0009] In one or more embodiments, the diffusion surface is an arc surface extending along the second direction.

[0010] In one or more embodiments, the second protrusion includes a microstructure disposed on the first side or the second side and a reflective layer covering the surface of the microstructure opposite to the first protrusion.

[0011] Preferably, the reflective layer is a metal reflective layer.

[0012] Preferably, the reflective layer is an aluminum film.

[0013] In one or more embodiments, the second protrusion further includes a protective layer covering the surface of the reflective layer opposite to the microstructure.

[0014] Preferably, the protective layer is a silicon dioxide layer.

[0015] In one or more embodiments, the diameter of the microstructure gradually decreases in the direction away from the first protrusion.

[0016] Preferably, the microstructure is a pyramid-shaped structure.

[0017] In one or more embodiments, the plurality of second protrusions are evenly arranged in several rows on the first side and the second side, and each row of second protrusions extends along the second direction.

[0018] In one or more embodiments, a gap is provided between adjacent second protrusions in the same row, and a gap is provided between adjacent rows of second protrusions.

[0019] To achieve the above objectives, another technical solution adopted in this application is to provide a method for preparing a brightness enhancement film, comprising:

[0020] A film layer is provided, the film layer including a first surface;

[0021] A plurality of first protrusions are formed by coating and curing an adhesive on the first surface along a first direction. The first protrusions extend along a second direction, and the surface of the first protrusions facing away from the first film layer includes a first side surface and a second side surface located on both sides, and a diffusion surface located between the first side surface and the second side surface.

[0022] A plurality of evenly arranged second protrusions are provided on the first side and the second side.

[0023] In one or more embodiments, the step of providing a plurality of uniformly arranged second protrusions on the first side and the second side includes:

[0024] Deposition and etching are performed on the first and second sides to form several uniformly arranged microstructures;

[0025] A reflective layer is provided on the surface of the microstructure opposite to the first protrusion.

[0026] A protective layer is provided on the surface of the reflective layer that is opposite to the microstructure.

[0027] To achieve the above objectives, another technical solution adopted in this application is to provide a backlight module, comprising:

[0028] The brightening film described in any of the above embodiments;

[0029] A diffusion film is disposed on a second surface of the film layer that is opposite to the first surface;

[0030] A reflective film is disposed on the side opposite to the diffuser film and the brightening film.

[0031] The advantages of this application, which differ from existing technologies, are:

[0032] The first surface of the brightness enhancement film layer of this application is provided with a plurality of first protrusions. The surface of the first protrusions facing away from the film layer includes a first side surface, a second side surface, and a diffusion surface. The diffusion surface can diffuse light and effectively improve the viewing angle. The first side surface and the second side surface are provided with a plurality of second protrusions. The second protrusions can reflect the light incident on the first side surface and the second side surface back to the first protrusions. After multiple reflections, the light is emitted through the diffusion surface. At the same time, some ambient light is reflected and guided to the diffusion surface, and some ambient light is emitted back into the air, thereby effectively improving the light utilization rate and improving the viewing angle.

[0033] The backlight module of this application can convert internal useless light and external ambient light into useful wide-angle light and collimated light, thereby greatly improving light utilization and viewing angle, meeting the needs of large-size, thin LCD displays. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of one embodiment of the backlight module of this application;

[0035] Figure 2 This is a schematic diagram of the structure of one embodiment of the brightness enhancement film of this application;

[0036] Figure 3 This is a schematic diagram of the structure of a traditional brightness enhancement film;

[0037] Figure 4 This is a schematic diagram of another embodiment of the brightness enhancement film of this application;

[0038] Figure 5 This is a schematic diagram of another embodiment of the brightness enhancement film of this application;

[0039] Figure 6 This is a three-dimensional structural schematic diagram of one embodiment of the brightness enhancement film of this application;

[0040] Figure 7 This is a schematic flowchart of one embodiment of the method for preparing the brightness enhancement film of this application;

[0041] Figure 8 yes Figure 7 A flowchart of one embodiment corresponding to step S30. Attached image description:

[0043] 1. Brightness enhancement film; 10. Film layer; 101. First surface; 102. Second surface; 11. First protrusion; 111. First side surface; 112. Second side surface; 113. Diffusion surface; 12. Second protrusion; 121. Microstructure; 122. Reflective layer;

[0044] 2. Diffusion membrane;

[0045] 3. Reflective film. Detailed Implementation

[0046] The present application will now be described in detail with reference to the embodiments shown in the accompanying drawings. However, these embodiments do not limit the present application, and any structural, methodological, or functional modifications made by those skilled in the art based on these embodiments are included within the protection scope of the present application.

[0047] Currently, in order to reduce the thickness of LCD displays, backlight modules generally adopt side-lit backlight modules, that is, the light source is placed on the side, and the light is guided through the diffusion film and the brightness enhancement film by the light guide sheet to achieve light dispersion and brightness enhancement.

[0048] As LCD displays become larger and thinner, the requirements for light source utilization and wide viewing angle of backlight modules are gradually increasing. However, the brightness enhancement film 1 of the backlight module in the existing technology only controls the viewing angle through a uniformly arranged prism structure, which cannot meet the requirements.

[0049] To this end, the applicant has developed a backlight module that can effectively improve light source utilization and increase viewing angle. Please refer to [link / reference]. Figure 1 , Figure 1 This is a schematic diagram of one embodiment of the backlight module of this application.

[0050] The backlight module includes a brightness enhancement film 1, a diffusion film 2, and a reflective film 3 arranged in sequence, wherein the reflective film 3 is disposed on the side of the diffusion film 2 that is away from the brightness enhancement film 1.

[0051] The diffuser 2 disperses the focused light and improves the viewing angle; the brightening film 1 focuses the light into a certain angle, thereby improving the brightness; and the reflective film 3 reflects the light emitted by the brightening film 1 and the diffuser 2 back to the diffuser 2 and the brightening film 1, thereby improving the utilization rate of the light source.

[0052] Please see Figure 2 , Figure 2 This is a schematic diagram of one embodiment of the brightness enhancement film of this application.

[0053] The brightness enhancement film 1 includes a film layer 10, which includes a first surface 101 and a second surface 102 disposed opposite to each other. Specifically, in this embodiment, the second surface 102 is the side surface close to the diffusion film 2, and the first surface 101 is the side surface away from the diffusion film 2.

[0054] The first surface 101 is provided with a plurality of first protrusions 11, which are arranged along a first direction.

[0055] The first protrusion 11 extends along the second direction, and the surface of the first protrusion 11 facing away from the first film layer 10 includes a first side surface 111 and a second side surface 112 located on both sides, and a diffusion surface 13 located between the first side surface 111 and the second side surface 112.

[0056] The diffuser surface 13 is used to diffuse light, thereby improving the viewing angle.

[0057] Specifically, the diffusion surface 13 is an arc surface that extends along the second direction.

[0058] Understandable, such as Figure 2 As shown, when light ray a1 is emitted from the first protrusion 11 with denser light and passes through the top of the arc surface into the outer air with less light, the angle of refraction of the light ray is greater than the angle of incidence. Since the diffusion surface 13 is an arc surface, the angle of the reflecting surface gradually decreases from both sides to the center position, which will cause the light ray to diverge after refraction, thereby effectively improving the viewing angle. When light ray a2 is emitted from the side of the arc surface into the outer air with less light, it will form collimated light that is emitted into the air.

[0059] However, for the traditional prism structure of brightness enhancement film 1, please refer to... Figure 3 , Figure 3 This is a schematic diagram of the structure of a traditional brightness enhancement film 1. When light is emitted from the prism structure, it will converge, resulting in a narrowing of the viewing angle.

[0060] In this embodiment, the second direction of the extension of the first protrusion 11 is a direction perpendicular to the first direction on the first surface 101. In other embodiments, the second direction may also be a direction that is inclined to the first direction on the first surface 101, which can achieve the effect of this embodiment.

[0061] In this embodiment, in order to ensure maximum dispersion of light, there is no gap between adjacent first protrusions 11, that is, the orthographic projection of several first protrusions 11 on the first surface 101 covers the entire first surface 101; in other embodiments, the gap between adjacent first protrusions 11 can also be adjusted according to the specific application scenario.

[0062] In this embodiment, both the first side surface 111 and the second side surface 112 are planar, and the first side surface 111 and the second side surface 112 are symmetrical with respect to the center plane a' of the first protrusion 11, thereby ensuring the symmetry of the light rays on both sides. For other embodiments, please refer to... Figure 4 and Figure 5 , Figure 4 This is a schematic diagram of another embodiment of the brightness enhancement film 1 of this application. Figure 5 This is a schematic diagram of another embodiment of the brightness enhancement film 1 of this application. The first side 111 and the second side 112 can also be curved surfaces. The first side 111 and the second side 112 can also not be symmetrical with respect to the center plane a' of the first protrusion 11. All of these can achieve the effect of this embodiment.

[0063] In order to further improve the light utilization rate and enhance the light brightness effect while improving the light viewing angle, the brightness enhancement film 1 in this embodiment also includes a plurality of second protrusions 12. The plurality of second protrusions 12 are evenly arranged on the first side surface 111 and the second side surface 112 of the first protrusion 11. The second protrusions 12 are used to guide the internal light and the external light to the diffusion surface 13.

[0064] Understandably, by directing the light from the inside of the first protrusion 11 to the first side 111, the second side 112, and the external light to the diffusion surface 13 through the second protrusion 12, the light utilization rate can be greatly improved and the brightening effect can be enhanced.

[0065] Specifically, the second protrusion 12 includes a microstructure 121 disposed on the first side 111 and the second side 112, and a reflective layer 122 covering the surface of the microstructure 121 facing away from the first protrusion 11.

[0066] Among them, the microstructure 121 is a pyramid-shaped structure with a diameter that gradually decreases in the direction away from the first protrusion 11, and the apex angle is 60°; the reflective layer 122 is an aluminum film.

[0067] like Figure 2 As shown, when light rays a3 and a4 enter the microstructure 121 from the first protrusion 11, they are reflected by both sides of the reflective layer 122 inside the microstructure 121 and return to the first protrusion 11. Then they pass through the diffusion film 2 and reach the reflective film 3, and are reflected back for reuse. After multiple reflections by the microstructure 121, the light rays are emitted from the diffusion surface 13 to form collimated light or wide-angle light, thereby effectively improving the light utilization rate and viewing angle.

[0068] To prevent damage to the microstructure 121 and the reflective layer 122 and to improve their service life, in this embodiment, the second protrusion 12 further includes a protective layer (not shown in the figure) covering the surface of the reflective layer 122 facing away from the microstructure 121. Specifically, the protective layer is a silicon dioxide protective layer; in other embodiments, the protective layer may also be made of other materials, as long as it can adequately protect the reflective film 3 while avoiding affecting the light.

[0069] like Figure 2 As shown, when ambient light rays a5 and a6 are directed toward the second protrusion 12, light ray a5 is totally reflected by the reflective layer 122 and directly emitted back into the air, forming useful light to improve gain; after being reflected by the second protrusion 12, light ray a6 undergoes a first refraction through the diffusion surface 13 and enters the first protrusion 11, and then undergoes a second refraction at the top of the diffusion surface 13 to form large-angle light.

[0070] Understandably, since the second protrusion 12 is distributed on the first side 111 and the second side 112, it reflects the light that is incident on the first side 111 and the second side 112 back to the first protrusion 11, and after multiple reflections, it is emitted through the diffusion surface 13. At the same time, it reflects and guides some of the ambient light to the diffusion surface 13, and some of the ambient light is emitted back into the air, which effectively improves the light utilization rate and enhances the gain effect.

[0071] Please see Figure 6 , Figure 6 This is a three-dimensional structural diagram of an embodiment of the brightness enhancement film 1 of this application. In this embodiment, the second protrusions 12 are evenly arranged in several rows on the first side 111 and the second side 112, and each row of the second protrusions 12 extends along the second direction.

[0072] To avoid the second protrusion 12 affecting the diffusion surface 13, the row of second protrusions 12 closest to the diffusion surface 13 is kept at a certain distance from the edge of the diffusion surface 13. In this embodiment, this distance can be 5 μm. In other embodiments, it can be adjusted according to the specific application scenario and the size of the second protrusion 12.

[0073] To allow some light rays to escape into the air from the first side 111 and the second side 112 without affecting the normal emission of light, a gap is provided between adjacent second protrusions 12 in the same row in this embodiment, and a gap is provided between adjacent rows of second protrusions 12, so that some light rays can escape through the gap. In other embodiments, adjacent second protrusions 12 may be tightly connected to maximize the light viewing angle.

[0074] Please see Figure 7 , Figure 7 This is a schematic flowchart of one embodiment of the preparation method of the brightness enhancement film 1 of this application.

[0075] The preparation method includes:

[0076] S10 provides a membrane layer, the membrane layer including a first surface.

[0077] The film layer 10 can be a PET film or other transparent materials.

[0078] S20 applies an adhesive to the first surface and cures it to form a plurality of first protrusions arranged along the first direction. The first protrusions extend along the second direction, and the surface of the first protrusions facing away from the first film layer includes a first side surface and a second side surface located on both sides, and a diffusion surface located between the first side surface and the second side surface.

[0079] Specifically, in this embodiment, a uniformly arranged first protrusion 11 is provided on the first surface 101 by applying an adhesive and curing it. In one application scenario, a UV-curable adhesive can be used to improve the curing effect of the first protrusion 11. In other application scenarios, other adhesives can also be used to achieve the effect of this embodiment.

[0080] S30 has several evenly arranged second protrusions on the first and second sides.

[0081] In one implementation, please refer to Figure 8 , Figure 8 yes Figure 7 A flowchart of one embodiment corresponding to step S30 is shown below. Step S30 specifically includes:

[0082] S301 is deposited and etched on the first and second sides to form several uniformly arranged microstructures.

[0083] The deposition can be atomic layer deposition or chemical vapor deposition, and the etching can be anti-ion etching or electron beam lithography. By first depositing and then etching, nanoscale microstructures can be obtained 121.

[0084] Specifically, in this embodiment, the MACE method is used to form a uniformly arranged silicon microstructure. The specific method is as follows: First, corrosion-resistant tape is attached to the side of the film layer 10 facing away from the first surface to prevent the back side from being viewed from above. Then, silver nanoparticles are deposited on the first and second sides. The film layer with the particles is immersed in an etching solution. The catalytic ability of the metal nanoparticles in the etching solution drives the chemical reaction to obtain a nanoarray morphology. After immersing in the silver plating solution for a certain period of time, it is immediately removed and dried with a nitrogen gun. Then, it is quickly immersed in the etching solution. By controlling the etching time, silicon nanoarrays of the same length can be obtained. Next, it is immersed in silver nitrate solution to remove the silver nanoparticles on the surface. Finally, it is rinsed with a large amount of deionized water to obtain a silicon microarray with a uniform morphology.

[0085] It is understood that in other embodiments, other deposition and etching methods can also be used to obtain uniformly arranged microstructures, all of which can achieve the effect of this embodiment.

[0086] S302 provides a reflective layer on the surface of the microstructure away from the first protrusion.

[0087] In one embodiment, the reflective layer 122 is specifically made of aluminum film. In other embodiments, a non-metallic reflective layer 122 or other metallic reflective layer 122 may also be used. The aluminum film can be coated on the surface of the microstructure 121 by nano-metal particle deposition or can be set on the surface of the microstructure 121 by other spraying methods. Both can achieve the effect of this embodiment.

[0088] S303 involves setting a protective layer on the surface of the reflective layer that faces away from the microstructure.

[0089] In one embodiment, the protective layer is specifically made of silicon dioxide and can be prepared by methods such as magnetron sputtering, ion beam sputtering, and chemical vapor deposition to cover the reflective layer 122 and effectively protect the reflective layer 122.

[0090] The foregoing description of this disclosure is provided to enable any person skilled in the art to implement or use this disclosure. Various modifications to this disclosure will be apparent to those skilled in the art, and the general principles applicable herein can be applied to other variations without departing from the scope of this disclosure. Therefore, this disclosure is not limited to the examples and designs described herein, but is consistent with the widest scope of the principles and novel features disclosed herein.

Claims

1. A high-increase, wide-viewing-angle brightening film, characterized in that, include: The film layer includes a first surface; A plurality of first protrusions are arranged along a first direction on the first surface, the first protrusions extend along a second direction, and the surface of the first protrusions facing away from the film layer includes a first side surface and a second side surface located on both sides and a diffusion surface located between the first side surface and the second side surface. A plurality of second protrusions are evenly arranged on the first side and the second side of the first protrusion. The second protrusions are used to guide internal light and external light to the diffusion surface. The second protrusions include microstructures disposed on the first side or the second side and a reflective layer covering the surface of the microstructures away from the first protrusion.

2. The brightening film according to claim 1, characterized in that, The diffusion surface is an arc surface that extends along the second direction.

3. The brightening film according to claim 1, characterized in that, The reflective layer is a metallic reflective layer.

4. The brightening film according to claim 3, characterized in that, The reflective layer is an aluminum film.

5. The brightening film according to claim 1, characterized in that, The second protrusion also includes a protective layer covering the surface of the reflective layer opposite to the microstructure; The protective layer is a silicon dioxide layer.

6. The brightening film according to claim 1, characterized in that, The diameter of the microstructure gradually decreases in the direction away from the first protrusion; The microstructure is a pyramid-shaped structure.

7. The brightening film according to claim 1, characterized in that, The plurality of second protrusions are evenly arranged in several rows on the first side and the second side, and each row of second protrusions extends along the second direction. A gap is provided between adjacent second protrusions in the same row, and a gap is provided between adjacent rows of second protrusions.

8. The brightening film according to claim 1, characterized in that, The first and second side surfaces are symmetrical with respect to the center plane of the first protrusion, and / or The first and second side surfaces are planes.

9. A method for preparing a brightness enhancement film, characterized in that, include: A film layer is provided, the film layer including a first surface; A plurality of first protrusions are formed by coating and curing an adhesive on the first surface along a first direction. The first protrusions extend along a second direction, and the surface of the first protrusions away from the film layer includes a first side surface and a second side surface located on both sides, and a diffusion surface located between the first side surface and the second side surface. A plurality of evenly arranged second protrusions are provided on the first side and the second side. The second protrusions are used to guide internal light and external light to the diffusion surface. The second protrusions include microstructures provided on the first side or the second side and a reflective layer covering the surface of the microstructures away from the first protrusions.

10. The preparation method according to claim 9, characterized in that, The step of providing a plurality of evenly arranged second protrusions on the first and second sides includes: Deposition and etching are performed on the first and second sides to form several uniformly arranged microstructures; A reflective layer is provided on the surface of the microstructure opposite to the first protrusion. A protective layer is provided on the surface of the reflective layer that is opposite to the microstructure.

11. A backlight module, characterized in that, include: The brightening film according to any one of claims 1 to 8; A diffusion film is disposed on a second surface of the film layer that is opposite to the first surface; A reflective film is disposed on the side opposite to the diffuser film and the brightening film.

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