Optical film, backlight module, and display device

Abstract

An optical film, a backlight module, and a display device. The optical film comprises a base film layer (11), wherein a plurality of diffusion structures (111) are provided in the base film layer (11), the diffusion structures (111) are hollow structures, and diffusion particles (112) are provided in the diffusion structures (111).

Description

Optical film, backlight module and display device

[0001] The present application claims priority from the Chinese patent application No. 202510484099.5 filed on April 16, 2025, and entitled "Optical film, backlight module and display device", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the field of optical technology, in particular to an optical film, a backlight module and a display device. BACKGROUND

[0003] In a backlight display system, the divergence angle of light emitted by a single point light source is limited, resulting in the phenomenon that the energy of the central region is greater than that of the surrounding region on the light emitting surface. The traditional technology usually covers the film and diffusion plate or light guide plate with diffusion and brightening functions above the light emitting surface of the light source to achieve diffusion and mixing of light, thereby achieving uniform light emission on the light emitting surface. TECHNICAL PROBLEM

[0004] The current light uniformity sheet is not balanced in terms of haze and transmittance, and it cannot guarantee good transmittance when a certain haze is reached. If the transmittance is not high, a large amount of backlight power will be required, which not only consumes a lot of energy but also affects the service life of the lamp beads. Therefore, the application of the light uniformity film in the backlight display system is of great significance to improve the display effect and energy efficiency. TECHNICAL SOLUTION

[0005] The present application provides an optical film, a backlight module and a display device, which can alleviate the problem of imbalance between haze and transmittance of the current optical film.

[0006] The present application provides an optical film, which comprises a base film layer, a plurality of diffusion structures are arranged in the base film layer, the diffusion structure is a hollow structure, and diffusion particles are arranged in the diffusion structure.

[0007] In some embodiments, the diffusion structure is an ellipsoidal structure.

[0008] In some embodiments, the diameter of at least part of the diffusion structure is less than 800 um.

[0009] In some embodiments, the diffusion particle is a spherical structure.

[0010] In some embodiments, the diameter of at least part of the spherical structure is d, wherein 2 um≤d≤50 um.

[0011] In some embodiments, the diffusion particle is a hollow structure.

[0012] In some embodiments of the optical film, the diffusing particles are glass spheres.

[0013] In some embodiments of the optical film, at least part of the inner wall thickness of the diffused particles is w, where 1um ≤ w ≤ 3um.

[0014] In some embodiments, the optical film further includes a first microstructure layer and a second microstructure layer, with a base film layer located between the first microstructure layer and the second microstructure layer.

[0015] In some embodiments of the optical film, the microstructure in the first microstructure layer includes a pyramidal structure, and at least a portion of the pyramidal structure has a vertex angle of α, wherein 80° < α ≤ 100°.

[0016] In some embodiments of the optical film, the microstructure in the second microstructure layer includes a pyramidal structure, and at least a portion of the pyramidal structure has a vertex angle of b, wherein 40°≤b≤80°.

[0017] In some embodiments of the optical film, at least a portion of the pyramidal structure has a vertex angle of h, wherein 20um ≤ h ≤ 50um.

[0018] In some embodiments of the optical film, a refractive layer is deposited on the surface of both the first microstructure layer and the second microstructure layer, and the refractive index of the refractive layer is n, where 1.0 ≤ n ≤ 2.4.

[0019] In some embodiments of the optical film, the thickness of the refractive layer is c, where 0.1um ≤ c ≤ 10um.

[0020] This application also provides a backlight module, which includes an optical film, a base film layer, and a plurality of diffusion structures in the base film layer. The diffusion structures are hollow and contain diffusion particles.

[0021] In some embodiments of the optical film, the diffusion structure is an ellipsoidal structure.

[0022] In some embodiments of the optical film, at least part of the diffusion structure has a diameter of less than 800 μm.

[0023] In some embodiments of the optical film, the diffused particles have a spherical structure.

[0024] In some embodiments of the optical film, at least a portion of the spherical structure has a diameter of d, wherein 2um ≤ d ≤ 50um.

[0025] This application also provides a display device, wherein the display device includes a backlight module, the backlight module includes an optical film, the optical film includes a base film layer, the base film layer includes a plurality of diffusion structures, the diffusion structures are hollow structures and diffusion particles are disposed in the diffusion structures. Beneficial effects

[0026] This application provides an optical film, a backlight module, and a display device. The optical film incorporates diffusion particles within a diffusion structure in its base layer. These diffusion particles scatter light, improving the film's haze and resulting in more uniform light distribution. Furthermore, the hollow diffusion structure reduces light absorption, ensuring a certain level of light transmittance while improving haze. Therefore, this application, by incorporating a hollow diffusion structure and diffusion particles into the optical film, can improve haze while maintaining a certain level of light transmittance, thus alleviating the current problem of imbalance between haze and light transmittance in optical films. Attached Figure Description

[0027] The technical solution and other beneficial effects of this application will become apparent from the following detailed description of specific embodiments in conjunction with the accompanying drawings.

[0028] Figure 1 is a schematic diagram of the first structure of the optical film provided in the embodiment of this application.

[0029] Figure 2 is a schematic diagram of the size of the diffusion structure and diffusion particles in Figure 1 provided in an embodiment of this application.

[0030] Figure 3 is a schematic diagram of a second structure of the optical film provided in an embodiment of this application.

[0031] Figure 4 is a schematic diagram showing the dimensions of the first microstructure layer and the second microstructure in Figure 3 provided in an embodiment of this application.

[0032] Figure 5 is a schematic diagram of the third structure of the optical film provided in the embodiments of this application.

[0033] Figure 6 is a schematic diagram of the optical path before and after the refractive layer is laid in the optical film provided in the embodiment of this application.

[0034] Reference numerals: 11, base film layer; 12, first microstructure layer; 13, second microstructure layer; 14, refractive layer; 111, diffusion structure; 112, diffusion particles. Detailed Implementation

[0035] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0036] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Features thus defined as "first" and "second" may explicitly or implicitly include one or more features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0037] Referring to Figure 1, this embodiment provides an optical film comprising a base film layer 11, in which a plurality of diffusion structures 111 are disposed. Each diffusion structure 111 is hollow and contains diffusion particles 112. In this embodiment, by placing diffusion particles 112 within the diffusion structures of the base film layer 11, the scattering of light by the diffusion particles 112 helps to improve the haze of the film, making the light distribution more uniform. Furthermore, since the diffusion structures 111 are hollow, their absorption of light is reduced, thus maintaining light transmittance while improving haze. Therefore, this application, by providing hollow diffusion structures 111 and diffusion particles 112 in the optical film, can improve the haze of the optical film while ensuring a certain level of light transmittance, thereby alleviating the problem of the imbalance between haze and light transmittance in current optical films.

[0038] In some embodiments, the diffusion structure 111 in this embodiment is an ellipsoidal structure, that is, the hollow diffusion structure 111 is ellipsoidal. By setting diffusion particles 112 in the ellipsoidal diffusion structure 111, the haze of the film is improved by the scattering of the diffusion particles 112. The diffusion particles 112 are located in the hollow structure. The setting of the hollow structure can reduce the absorption of light and is beneficial to improve the light transmittance.

[0039] Referring to Figure 2, in some embodiments, the diameter of at least part of the ellipsoidal diffusion structure is less than 800 μm. For example, if the ellipsoidal diffusion structure 111 extends horizontally, then the maximum dimension of the diffusion structure 111 in the horizontal direction is less than 800 μm, such as a maximum diameter of 750 μm or 700 μm. In this embodiment, the diffusion structure 111 is set to a certain size to ensure that a certain gap is formed around the diffusion particles 112, which helps to reduce light absorption and ensure the light transmittance of the optical film.

[0040] In some embodiments, the diffuser particle 112 can be a solid spherical structure, and correspondingly, at least part of the spherical structure has a diameter of d, where 2µm ≤ d ≤ 50µm. For example, the diameter of the diffuser particle 112 is 2µm to 20µm. In this embodiment, by setting spherical diffuser particles 112 in the diffuser structure 111, light can be focused to a certain emission angle, thereby enhancing the brightness of the emitted light. The surface curvature of the spherical diffuser particle 112 is relatively uniform, which can effectively scatter light, thereby achieving a better atomization effect and improving the haze of the optical film. At the same time, the spherical diffuser particle 112 has good symmetry, and the light is not easily affected by the irregularity of the particle shape, which is beneficial to improving the uniformity of light emission. Of course, in other embodiments, diffuser particles 112 of other shapes can be selected, and microstructures can also be provided on the surface of the diffuser particle 112; this application does not limit this.

[0041] In another embodiment, the diffuser particle 112 can also be a hollow structure. If the diffuser particle 112 is a hollow spherical structure, and at least part of the diffuser particle has an inner wall thickness of w, then 1um ≤ w ≤ 3um. Similarly, setting the diffuser particle 112 as a hollow structure can further reduce the absorption of light by the diffuser particle 112, ensuring that the diffuser particle 112 scatters light to improve haze while ensuring a certain light transmittance.

[0042] As one embodiment, the diffuser particle 112 can be a glass sphere, that is, in this embodiment, the material of the diffuser particle 112 is glass. Transparent glass is preferred to facilitate light transmission. However, in other embodiments, materials with the same function can also be selected to form the diffuser particle 112, and this application does not limit this choice.

[0043] As one embodiment, the base film layer 11 can be a PET (Polyethylene Terephthalate) base film. Of course, a base film with the same function can also be selected in other embodiments, and this application does not limit this.

[0044] Referring to Figure 3, in some embodiments, the optical film further includes a first microstructure layer 12 and a second microstructure layer 13, with the base film layer 11 located between the first microstructure layer 12 and the second microstructure layer 13. The first microstructure layer 12 and the second microstructure layer 13 are respectively disposed on opposite sides of the base film layer 11. For example, if the first microstructure layer 12 is disposed on the light-incident side of the base film layer 11, then the second microstructure layer 13 is disposed on the light-emitting layer of the base film layer 11. In this embodiment, by providing microstructure layers in the base film layer 11, it is beneficial to enhance the scattering and uniformity of light in the optical film.

[0045] As one embodiment, the microstructures in the first microstructure layer 12 and the second microstructure layer 13 in this embodiment include pyramidal structures. For example, octagonal pyramids, hexagonal pyramids, or square pyramids are provided. In this embodiment, by providing pyramidal microstructures, it is beneficial to reduce light reflection loss and improve light transmittance. The pyramidal structure can effectively change the direction of light propagation, causing light to undergo multiple refractions and reflections when passing through the pyramidal structure, thereby achieving a more uniform light distribution.

[0046] Please refer to Figure 4. As one embodiment, at least some of the pyramidal structures have a vertex angle of 'a' and at least some of the pyramidal structures have a vertex angle of 'b'. Wherein, 80° < a ≤ 100°, for example, the vertex angle of the pyramidal structure in the first microstructure layer 12 is 90 degrees; wherein, 40° ≤ b ≤ 80°. That is, in this embodiment, the vertex angle of the pyramids in one microstructure layer is larger, while the vertex angle of the pyramids in the other microstructure layer is smaller. A smaller vertex angle causes light to be reflected more frequently on the pyramidal surface, thereby increasing the scattering angle of the light and making the light distribution more uniform. A larger vertex angle causes light to be reflected or refracted more concentratedly in a specific direction, thereby reducing the scattering angle and increasing the light intensity in that specific direction, which is beneficial for improving the brightness of the light.

[0047] As one embodiment, at least a portion of the pyramidal structures in the first microstructure layer 12 and the second microstructure layer 13 have a height of h, where 20µm ≤ h ≤ 50µm, such as a pyramidal structure height of 30µm. In this embodiment, to alleviate the problem of light crosstalk, the height of the pyramidal structure is controlled within a certain range: specifically, with a smaller pyramidal structure, the propagation path of light inside the pyramid is shortened, and the scattering angle is increased, thereby making the light more uniform; at the same time, with a smaller pyramidal structure, the number of reflections of light inside the pyramid is reduced, which is beneficial to improving the light transmittance.

[0048] Please refer to Figures 5 and 6 together. In some embodiments, a coating is deposited on the surfaces of both the first microstructure layer 12 and the second microstructure layer 13 to form a refractive layer 14, and the refractive index of the refractive layer 14 is n, where 1.0 ≤ n ≤ 2.4. The material of the refractive layer 14 can be titanium oxide, titanium trioxide, titanium pentoxide, titanium monoxide, zirconium dioxide, or zinc sulfide, etc. In this embodiment, by setting a coating with a high refractive index, it is beneficial to improve the diffusion angle of light.

[0049] In one embodiment, the thickness of the refractive layer 14 is c, where 0.1um ≤ c ≤ 10um, and the thickness of the refractive layer 14 is 0.5um-2um. In this embodiment, by setting the refractive layer 14, the angle of light diffusion through optical refraction can be improved, which is beneficial to improving the beam splitting effect of the optical film.

[0050] This application also provides a backlight module, which includes the aforementioned optical film. Since the optical film has been described in detail above, it will not be repeated here.

[0051] This application also provides a display device, which includes the backlight module described above. The display device may be a liquid crystal television, and the corresponding backlight module may be a liquid crystal backlight module. The backlight module uses the optical film described above; since the optical film has been described in detail above, it will not be repeated here.

[0052] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0053] The optical films provided in the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are only for the purpose of helping to understand the technical solutions and core ideas of this application. Those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. An optical film, wherein, The optical film includes a base film layer, which contains multiple diffusion structures. The diffusion structures are hollow and contain diffusion particles.

2. The optical film according to claim 1, wherein, The diffusion structure is an ellipsoidal structure.

3. The optical film according to claim 2, wherein, At least a portion of the diffusion structure has a diameter of less than 800 μm.

4. The optical film according to claim 2, wherein, The diffused particles have a spherical structure.

5. The optical film according to claim 4, wherein, The diameter of at least part of the spherical structure is d, where 2um ≤ d ≤ 50um.

6. The optical film according to claim 1, wherein, The diffused particles have a hollow structure.

7. The optical film according to claim 1, wherein, The diffused particles are glass spheres.

8. The optical film according to claim 6, wherein, The inner wall thickness of at least some of the diffused particles is w, where 1um ≤ w ≤ 3um.

9. The optical film according to claim 1, wherein, The optical film further includes a first microstructure layer and a second microstructure layer, with the base film layer located between the first microstructure layer and the second microstructure layer.

10. The optical film according to claim 9, wherein, The microstructures in the first microstructure layer include pyramidal structures, at least a portion of which have a vertex angle of α, wherein 80° < α ≤ 100°.

11. The optical film according to claim 9, wherein, The microstructures in the second microstructure layer include pyramidal structures, at least a portion of which have a vertex angle of b, wherein 40°≤b≤80°.

12. The optical film according to claim 10 or 11, wherein, The height of at least part of the pyramidal structure is h, where 20um ≤ h ≤ 50um.

13. The optical film according to claim 9, wherein, The surfaces of both the first and second microstructure layers are covered with a refractive layer, and the refractive index of the refractive layer is n, where 1.0 ≤ n ≤ 2.

4.

14. The optical film according to claim 13, wherein, The thickness of the refractive layer is c, where 0.1um ≤ c ≤ 10um.

15. A backlight module, wherein, The backlight module includes an optical film, which includes a base film layer. The base film layer includes multiple diffusion structures, which are hollow and contain diffusion particles.

16. The backlight module according to claim 15, wherein, The diffusion structure is an ellipsoidal structure.

17. The backlight module according to claim 16, wherein, At least a portion of the diffusion structure has a diameter of less than 800 μm.

18. The backlight module according to claim 16, wherein, The diffused particles have a spherical structure.

19. The backlight module according to claim 18, wherein, The diameter of at least part of the spherical structure is d, where 2um ≤ d ≤ 50um.

20. A display device, wherein, The display device includes a backlight module, the backlight module includes an optical film, the optical film includes a base film layer, the base film layer includes a plurality of diffusion structures, the diffusion structures are hollow structures and diffusion particles are disposed in the diffusion structures.

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