Optical film, polarizer, and display device

Abstract

The invention discloses an optical film, a polaroid and a display device, the optical film comprises a base material and particles dispersed in the base material, under the overlooking view angle of the optical film, the number of the particles dispersed in every ten thousand square micrometers is smaller than or equal to 400, the ratio of the number of the particles dispersed in every ten thousand square micrometers to the haze of the optical film is larger than zero and smaller than or equal to 100, and the number of the particles dispersed in every ten thousand square micrometers is smaller than or equal to 100. Through the design, the difference between the in-plane retardation value and the retardation value in the thickness direction of the optical film can be reduced, the rainbow pattern phenomenon is improved, the optical film has excellent mechanical performance, meanwhile, the chromaticity visual angle of the optical film when the optical film is applied to the display device can be improved, and high transmittance is maintained.

Description

Technical Field

[0001] The present application relates to the field of display technology, and in particular to an optical film, a polarizer, and a display device. Background Art

[0002] Polarizers are widely used in the display industry. Typically, an optical film is used to protect the polarizing layer of a polarizer. However, because optical films typically exhibit birefringence and anisotropy in their refractive index, light passing through the film is decomposed into ordinary light and extraordinary light, each with a specific retardation value. If the retardation value of these two light sources exceeds a certain range, light interference occurs, forming rainbow patterns. This can degrade display quality when the polarizer is used in a display device.

[0003] In addition, in order to improve the chromaticity and color angle of the display, diffusion particles are added to the optical film. However, the inventors have found that when the diffusion particles are added to a certain range, they will have an adverse effect on the in-plane delay value of the optical film, resulting in a large difference between the in-plane delay value and the thickness direction delay value, causing the rainbow pattern to worsen. Summary of the Invention

[0004] The embodiments of the present application provide an optical film, a polarizer, and a display device to solve the technical problem that adding a certain amount of diffusion particles to the existing optical film may cause the risk of worsening rainbow patterns.

[0005] To solve the above problems, the technical solutions provided by this application are as follows:

[0006] An embodiment of the present application provides an optical film, comprising a substrate and particles dispersed in the substrate; wherein, at a top-view angle of the optical film, the number of particle top-view patterns dispersed in every 10,000 square microns of the optical film top-view pattern is greater than 0 and less than or equal to 400, and the ratio of the number of particle top-view patterns dispersed in every square micron of the optical film top-view pattern to the haze of the optical film is greater than zero and less than or equal to 100.

[0007] In some embodiments of the present application, at a top-view angle of the optical film, the number of the particle top-view patterns dispersed within every 10,000 square microns of the optical film top-view pattern is greater than 10 and less than 300, and the ratio of the number of the particle top-view patterns dispersed within every square micron of the optical film top-view pattern to the haze of the optical film is greater than 0 and less than 20.

[0008] In some embodiments of the present application, the number of the particles dispersed in every 10,000 cubic microns of the optical film is greater than 0 and less than or equal to 300, and the ratio of the number of the particles dispersed in each cubic microparticle to the haze is greater than zero and less than or equal to 100.

[0009] In some embodiments of the present application, at a top-view angle of the optical film, the number of the particle top-view patterns dispersed in every 10,000 square microns of the optical film top-view pattern is greater than 10 and less than 300, and the ratio of the number of the particle top-view patterns dispersed in every square micron of the optical film top-view pattern to the haze of the optical film is greater than 0 and less than 20; the number of the particles dispersed in every 10,000 cubic microns of the optical film is greater than or equal to 20 and less than 300, and the ratio of the number of the particles dispersed in every cubic micron to the haze is greater than 0 and less than or equal to 20.

[0010] In some embodiments of the present application, the haze is greater than zero and less than 100%.

[0011] In some embodiments of the present application, the haze is greater than or equal to 0.01% and less than or equal to 20%.

[0012] In some embodiments of the present application, the in-plane retardation value of the optical film is less than or equal to 3000 nanometers, and the thickness direction retardation value of the optical film is less than or equal to 6000 nanometers.

[0013] In some embodiments of the present application, the difference between the slow-axis refractive index of the optical film and the fast-axis refractive index of the optical film is less than or equal to 0.15.

[0014] In some embodiments of the present application, the breaking strength of the optical film is 10N / mm 2 Up to 500N / mm 2 , the elongation at break is 10% to 200%.

[0015] In some embodiments of the present application, the breaking strength of the optical film is 50N / mm 2 Up to 350N / mm 2 , the elongation at break is 30% to 200%.

[0016] In some embodiments of the present application, at a top-view angle of the optical film, the number of the particle top-view patterns dispersed in every 10,000 square microns of the optical top-view pattern is greater than 10 and less than 300, and the ratio of the number of the particle top-view patterns dispersed in every square micron of the optical film top-view pattern to the haze of the optical film is greater than or equal to 0 and less than or equal to 2; the number of the particles dispersed in every 10,000 cubic particles of the optical film is greater than or equal to 20 and less than or equal to 300, the haze is greater than or equal to 1% and less than or equal to 6%, and the ratio of the number of the particles dispersed per cubic micron to the haze is greater than or equal to 0 and less than or equal to 2.

[0017] In some embodiments of the present application, the in-plane retardation value of the optical film is less than or equal to 190 nanometers, and the thickness direction retardation value of the optical film is less than or equal to 500 nanometers.

[0018] In some embodiments of the present application, the difference between the slow-axis refractive index of the optical film and the fast-axis refractive index of the optical film is greater than or equal to 0.003 and less than or equal to 0.007.

[0019] In some embodiments of the present application, the melt index of the optical film is greater than or equal to 0.35 and less than or equal to 0.55; and / or the crystallinity of the optical film is greater than or equal to 15% and less than or equal to 35%.

[0020] In some embodiments of the present application, the substrate includes but is not limited to cellulose triacetate, polyethylene terephthalate, polycarbonate, polymethyl methacrylate, polycycloolefin, and polyethylene naphthalate.

[0021] In some embodiments of the present application, the shape of the particles includes at least one of a sphere, an ellipsoid, a cube, a cuboid, a cone, a cylinder, a prism, a sheet, a single needle, a three-needle, a four-needle, a petal, a disc, and a spiral.

[0022] In some embodiments of the present application, the material of the particles includes at least one of polymethyl methacrylate, polystyrene, silicone, polybutyl acrylate-styrene, poly-4-hydroxybenzyl ester, silicon dioxide, silicon carbide, silicon nitride, zinc oxide, magnesium oxide, aluminum oxide, calcium sulfate, calcium carbonate, potassium titanate, and aluminum borate.

[0023] In some embodiments of the present application, the particles account for less than 30% by weight of the optical film.

[0024] In some embodiments of the present application, the thickness of the optical film is 5 micrometers to 500 micrometers.

[0025] In some embodiments of the present application, the particle size of the particles is greater than or equal to 0.1 micrometers and less than or equal to 300 micrometers.

[0026] In some embodiments of the present application, the glass transition temperature of the substrate is 20°C to 600°C.

[0027] Based on the optical film in the above embodiments, an embodiment of the present application further provides a polarizer, comprising a polarizing layer and the optical film of any of the above embodiments, wherein the slow axis direction of the optical film is perpendicular to the absorption axis of the polarizing layer.

[0028] In some embodiments of the present application, the polarizer further includes an optical functional layer located on the side of the optical film away from the polarizing layer, and the optical functional layer includes at least one of an anti-glare layer, a hard coating layer, an anti-reflection layer, a low-reflection layer, an anti-fingerprint layer, and an anti-static layer.

[0029] Based on the polarizer in the above embodiments, an embodiment of the present application further provides a display device, comprising the polarizer and a display panel of any of the above embodiments.

[0030] The beneficial effects of the present application are as follows: under the top-down viewing angle of the optical film of the present application, the number of particles per 10,000 square microns is designed to be less than or equal to 400, and the ratio of the number of dispersed particles per square micron to the haze is designed to be greater than zero and less than or equal to 100. Through the above design, not only can the difference between the in-plane delay value and the delay value in the thickness direction of the optical film be reduced, the rainbow pattern phenomenon can be improved, and it has excellent mechanical properties, but it can also improve the chromaticity viewing angle when the optical film is applied to a display device and maintain a higher transmittance. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0032] Figure 1 A schematic structural diagram of an optical film provided in an embodiment of the present application;

[0033] Figure 2 A schematic structural diagram of a polarizer provided in an embodiment of the present application;

[0034] Figure 3 A schematic structural diagram of a display device provided in an embodiment of the present application. 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 embodiments described 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 making creative efforts are within the scope of protection of this application.

[0036] In the description of this application, it should be understood that the terms "thickness", "upper", "lower", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on this application.

[0037] The disclosure below provides many different embodiments or examples for realizing different structures of the present application. In order to simplify the disclosure of the present application, the components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the present application. In addition, the present application may repeat reference numbers and / or reference letters in different examples, and such repetition is for the purpose of simplicity and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present application provides examples of various specific processes and materials, but those of ordinary skill in the art will appreciate the application of other processes and / or the use of other materials.

[0038] This application targets existing optical films and adds particles to the optical films in order to improve the chromaticity and color angle of the display. However, when the amount of diffusion particles added reaches a certain range, it will have an adverse effect on the in-plane retardation value of the optical film, resulting in a large difference between the in-plane retardation value and the thickness direction retardation value, causing the rainbow pattern to worsen. This embodiment is proposed to overcome this defect.

[0039] like Figure 1 As shown, the embodiment of the present application provides an optical film 10, which includes a substrate 11 and particles 12 dispersed in the substrate 11. In the top view of the optical film 10, every 10,000 square microns (10,000 μm 2 ) of the optical film top view pattern is greater than 0 and less than or equal to 400, that is, per square micron / unit area (μm 2 ) The number of particle top view patterns R1 within the unit area (μm) is greater than 0 and less than or equal to 0.04. 2 ) and the haze H of the optical film 10 is defined as ξ1, which is greater than zero and less than or equal to 100.

[0040] In the embodiments of this application, "top-down viewing angle" refers to the angle of observation from directly above the optical film (including but not limited to observation using an instrument such as a microscope). "Optical film top-down pattern" refers to the specific pattern presented on the surface of the optical film when observed from directly above the optical film (including but not limited to the outer contour of the optical film and the microstructure within the film layer). "Particle top-down pattern" refers to the specific pattern presented by particles when observed from directly above the optical film.

[0041] Doping the optical film 10 with particles can improve the chromaticity and viewing angle of the optical film 10 when applied to a display device. However, the addition of particles can increase haze, affecting transmittance. The inventors have also discovered that adding particles within a certain range of values can worsen the rainbow pattern of the optical film 10. The optical film 10 provided in the embodiments of the present application, by designing the number R1 of particle top-view patterns per unit area and the value ξ1 (R1 / H) within the aforementioned ranges, can not only reduce the difference between the in-plane retardation value and the retardation value in the thickness direction of the optical film 10, thereby improving the rainbow pattern phenomenon, but also has excellent mechanical properties. It can also improve the chromaticity and viewing angle of the optical film 10 when applied to a display device while maintaining a high transmittance.

[0042] It is worth noting that, in a top-down perspective, the number of particle patterns within each 10,000 square micrometers of the optical film top-down pattern can be counted by observing and counting using a microscope. For example, the optical film can be cut into sheets of a certain size, laid flat under an optical microscope (OM) or a scanning electron microscope (SEM), and a 10,000 μm frame can be selected. 2 Count the particles in an area of ​​the optical film, or select a larger area and count the particles. The number of particles per 10,000 square microns is calculated. This is the number of particles in the top-down pattern of the optical film per 10,000 square microns when viewed from above. It is worth noting that when counting particles observed under a microscope, if two or more particles overlap, the overlapping particles are counted as one particle.

[0043] In some embodiments, when viewed from above, the number of particles per 10,000 square microns of the optical film 10 may be 5, 10, 15, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, 400, or a value between any two of the above values, or a range formed by any two of the above values.

[0044] Optionally, in some embodiments, under the top-view angle of the optical film, the number of dispersed particle top-view patterns in each 10,000 square micrometers of optical top-view pattern is greater than 10 and less than 300, that is, the number of particle top-view patterns per unit area (μm) is greater than 10 and less than 300. 2) is 0.03, and a ratio ξ1 of the number R1 of the particle top-view patterns dispersed in the optical film top-view pattern per square micrometer to the haze H of the optical film is greater than 0 and less than 20. When R1 and ξ1 are within this range, the difference between the in-plane retardation value and the retardation value in the thickness direction of the optical film 10 can be further reduced, thereby improving the rainbow streak phenomenon.

[0045] In some embodiments, the haze H of the optical film 10 is greater than 0 and less than 100%. Alternatively, the haze of the optical film 10 may be 0.01%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 22%, 24%, 26%, 28%, 30%, 35%, 40%, 45%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or a value between any two of the above values, or a range formed by any two of the above values.

[0046] In an embodiment of the present application, the haze H of the optical film 10 may be greater than or equal to 0.01% and less than or equal to 20%. Within this range, the rainbow stripe phenomenon can be effectively improved and the mechanical properties can be enhanced while ensuring the transmittance. Specifically, in an embodiment of the present application, the in-plane delay value of the optical film 10 is less than or equal to 3000 nanometers, and the thickness direction delay value of the optical film 10 is less than or equal to 6000 nanometers. The in-plane delay value refers to the delay value in the plane where the optical film 10 is located, and the thickness direction delay value refers to the delay value in the direction perpendicular to the plane where the optical film 10 is located. The present application reduces the in-plane delay value of the optical film 10 by designing the number R1 of the top view pattern of particles per unit area, the haze H and the ξ1 value within the above range, so that the difference between the in-plane delay value and the thickness direction delay value is within a smaller range, thereby improving the rainbow stripe phenomenon.

[0047] In the embodiment of the present application, the in-plane retardation value and the thickness direction retardation value of the optical film 10 can be calculated according to the following formula:

[0048] Re=(n x -n y )d;

[0049]

[0050] Where Re is the in-plane retardation value, Rth is the thickness direction retardation value, d is the thickness of the optical film, and n is the thickness of the optical film. x is the refractive index in the slow axis direction (the direction with the largest refractive index) in the plane where the optical film is located, n y is the refractive index of the fast axis direction (the direction with the smallest refractive index) in the plane where the optical film is located, nz It is the refractive index in the direction perpendicular to the plane where the optical film is located, and the slow axis direction and the fast axis direction are orthogonal to each other.

[0051] In some embodiments, further, every 10,000 cubic microns (10,000 μm 3 ) is greater than 0 and less than or equal to 300, that is, per cubic micron / unit volume (μm 3 ) The number of particles R2 dispersed in the unit volume (μm) is greater than 0 and less than or equal to 0.03. 3 ) and the haze H, ξ2 (R2 / H) is greater than 0 and less than or equal to 100. By designing the number of particles R2 and the ξ2 value per unit volume of the optical film 10 to be within the above ranges, and combining them with the above R1 and ξ1, the particle distribution of the optical film 10 can be precisely controlled from two-dimensional and three-dimensional perspectives, thereby effectively reducing the difference between the in-plane retardation value and the retardation value in the thickness direction of the optical film 10, improving the rainbow streak phenomenon, and enhancing the mechanical properties of the optical film. At the same time, the chromaticity viewing angle of the optical film 10 when applied to a display device can be improved, while maintaining a high transmittance.

[0052] It is worth noting that the number of particles dispersed per 10,000 cubic microns of the optical film 10 (unit volume (μm 3 The number of particles R2) dispersed within a ) can be determined by the following method:

[0053] (1) Measure the initial mass M of the optical film sample and record the initial mass M1 of the crucible used for burning. Place the optical film sample in a muffle furnace and burn it at a set temperature (500℃-800℃) to completely decompose the organic matter and retain only the residual material (ash). After cooling, weigh the total mass M2 of the crucible and the residue and calculate the ash mass M ash =M2-M1.

[0054] (2) Obtain the particle density ρ through literature or actual measurement. If the particles are of uniform size, calculate the volume and obtain the mass m of each particle. If the particles are of uneven size, obtain the distribution data through a particle size distribution instrument (such as dynamic light scattering, SEM) and calculate the particle mass m in sections.

[0055] (3) Calculate the total number of particles N dispersed in the optical film sample: N = M ash / m.

[0056] In the embodiment of the present application, the slow axis refractive index n of the optical film 10 of the present application can be made to be 1000 nm by designing the number of particle top view patterns per unit area R1, the number of particles per unit volume R2, the haze H, and the values of ξ1 and ξ2. x and the fast axis refractive index n yThe difference is less than or equal to 0.15, which reduces the refractive index difference of the optical film 10 in different directions and improves the rainbow phenomenon.

[0057] Optionally, the number of the particles dispersed per 10,000 cubic microns of the optical film is greater than 20 and less than or equal to 300, and the ratio ξ2 of the number R2 of the particles dispersed per cubic micron to the haze H is greater than or equal to 0 and less than or equal to 20. Within this range, the difference between the in-plane retardation value and the retardation value in the thickness direction of the optical film 10 can be further reduced, thereby improving the rainbow streak phenomenon.

[0058] The optical film 10 can be manufactured by slicing the substrate 11, mechanically mixing the sliced substrate with particles, melt co-extrusion, film casting, and stretching. By designing the number of particle top-view patterns per unit area R1, the number of particles per unit volume R2, the haze H, and the values of ξ1 and ξ2, the optical film 10 of the present application can achieve a breaking strength of 10N / mm. 2 Up to 500N / mm 2 , has excellent resistance to tensile failure, the elongation at break can reach the range of 10% to 200%, and has excellent plastic deformation ability. Furthermore, the optical film 10 provided in the present application has excellent tensile properties.

[0059] Furthermore, the breaking strength of the optical film 10 can reach 50N / mm 2 Up to 350N / mm 2 , the elongation at break can reach 30% to 200%.

[0060] In some embodiments, the intrinsic viscosity of the slices of the substrate 11 after mechanical mixing with the particles can be controlled to be between 0.35 and 0.95. Accordingly, the optical film 10 can be characterized by a melt index, and the melt index of the optical film 10 is 0.35 to 0.55. Within this range, the mechanical properties of the optical film 10 can be further improved. Optionally, the melt index of the optical film 10 can be 0.35, 0.38, 0.40, 0.45, 0.48, 0.50, 0.55, or a range consisting of any two of the above values, or a value between any two of the above values. In the embodiments of the present application, the melt index can be tested by a melt index meter such as XNR 400, and the implementation standard is ASTM D 1238.

[0061] There is a certain degree of inverse relationship between the melt index of the film and the intrinsic viscosity of the slice. The intrinsic viscosity will affect the tensile / mechanical properties of the formed film. The higher the intrinsic viscosity of the slice, the better the tensile properties of the formed film and the better the mechanical properties. That is, if the melt index of the optical film 10 is small, the mechanical properties of the optical film 10 will be relatively better. Optionally, the melt index of the optical film 10 can be 0.38-0.55, 0.38-0.48, 0.45-0.48, or a value between any two ends of the above values. Within this range, while maintaining the excellent mechanical properties of the optical film 10, the difference in the retardation value of the optical film 10 in different directions can be reduced, thereby improving the rainbow pattern phenomenon.

[0062] In some embodiments, the crystallinity of the optical film 10 can be controlled between 15% and 35%. The crystallinity of the optical film 10 will affect the optical transmittance, haze, mechanical properties and retardation value of the film. By controlling the crystallinity of the optical film 10 within this range, it is possible to reduce optical loss while reducing the difference in retardation values of the optical film 10 in different directions, thereby improving the rainbow pattern phenomenon. Optionally, the crystallinity of the optical film 10 may be 15%, 17%, 19%, 20%, 21%, 22%, 25%, 28%, 30%, 32%, 35%, or a range consisting of any two of the above values, or a value between any two of the above values. In the embodiments of the present application, the crystallinity can be measured by the DSC (differential scanning calorimetry) method, specifically, it can be measured using a DSC3500Sirius differential scanning calorimeter.

[0063] Optionally, the crystallinity of the optical film 10 may be 15% to 25%, 19% to 25%, 19% to 22%, 17% to 21% or any value between the two ends of the above values. Controlling the crystallization within this range can not only ensure high transmittance, but also reduce the difference in the delay value of the optical film 10 in different directions over a large length, thereby improving the rainbow pattern phenomenon.

[0064] In some embodiments, the unit volume (μm 3 ) may be less than or equal to 0.008; further, may be less than or equal to 0.006; further, may be less than or equal to 0.004.

[0065] In some embodiments, the haze H may be less than or equal to 15%, further, less than or equal to 8%, further, less than or equal to 6%, and further, less than or equal to 2%.

[0066] In some embodiments, the unit volume (μm 3 ) and the haze H may be greater than or equal to 0.1 and less than or equal to 0.4.

[0067] In a specific embodiment, when viewed from above, the number of particles per 10,000 square microns is greater than 10 and less than 300, the ratio of the number R1 of the particles dispersed per square micron to the haze H of the optical film is greater than 0 and less than or equal to 2, and the number of particles per 10,000 cubic microns may be 20 to 300, that is, per unit volume (μm 3 ) can be greater than or equal to 0.002 and less than or equal to 0.03, the haze H can be greater than or equal to 1% and less than or equal to 6%, and ξ2 can be greater than or equal to 0 and less than or equal to 2. Within the above design range, the in-plane retardation value of the optical film 10 is less than or equal to 190 nanometers, and the thickness direction retardation value is less than or equal to 500 nanometers, which can further reduce the difference between the in-plane retardation value and the thickness direction retardation value, and further effectively improve the rainbow pattern. Within the above design range, the slow axis refractive index n of the optical film 10 is less than or equal to 190 nanometers, and the thickness direction retardation value is less than or equal to 500 nanometers. x and the fast axis refractive index n y The difference between them can be controlled to be 0.003 and less than or equal to 0.007, which effectively reduces the anisotropy of the refractive index of the optical film 10, reduces the interference of light, and thus improves the rainbow phenomenon.

[0068] In some embodiments, the substrate 11 of the optical film 10 has a glass transition temperature of 20°C to 600°C.

[0069] In some embodiments, the substrate 11 of the optical film 10 includes at least one of triacetyl cellulose (TAC), polyethylene terephthalate (PET), polycarbonate (PC), polymethyl methacrylate (PMMA), polycycloolefin (COP / COC), and polyethylene naphthalate (PEN). Alternatively, the substrate 11 of the optical film 10 may be a PET substrate. The substrate 11 may also be a mixed substrate of PET and PMMA.

[0070] In some embodiments, the thickness of the optical film 10 is 5 μm to 500 μm, specifically 5 to 50 μm, 10 to 60 μm, 30 to 80 μm, 5 to 450 μm, 10 to 400 μm, 20 to 350 μm, 30 to 300 μm, 40 to 250 μm, 45 to 200 μm, 50 to 150 μm, 60 to 120 μm, 65 to 100 μm, or a value between any two of the above end values.

[0071] In some embodiments, the particles dispersed within the substrate 11 may comprise less than 30% by weight of the optical film 10, specifically 0.1%, 0.2%, 0.3%, 0.5%, 0.8%, 1%, 2%, 3%, 5%, 8%, 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, or any value in between. Controlling the particle content within this range can balance the film's crystallinity, melt index, haze, and transmittance.

[0072] In some embodiments, the material of the particles 12 may include at least one of modified or unmodified inorganic substances and modified or unmodified organic substances. Inorganic substances may include, but are not limited to, silicon dioxide (SiO2), silicon carbide (SiC), silicon nitride (Si3N4), zinc oxide (ZnO2), magnesium oxide (MgO), aluminum oxide (Al2O3), calcium sulfate (CaSO4), calcium carbonate (CaCO3), potassium titanate (K6TiO4), and the like. 13 O6), aluminum borate (Al 18 B4O 33 ); the organic material may include, but is not limited to, at least one of polymethyl methacrylate (PMMA), polystyrene (PS), silicone, polybutyl acrylate-styrene, and poly-4-hydroxybenzyl ester. The above-mentioned particle materials may be surface-modified.

[0073] In some embodiments, the shape of the particle 12 may include at least one of a spherical shape and a non-spherical shape. Specifically, the shape of the particle includes, but is not limited to, at least one of a sphere, an ellipsoid, a cube, a cuboid, a cone, a cylinder, a prism, a sheet, a single needle (rod), a three-needle shape, a four-needle shape, a petal shape, a disk shape, and a spiral shape.

[0074] In some embodiments, the particle size of the particle 12 is 0.1 micron to 300 microns. When the shape of the particle is non-spherical, the particle size of the particle is 0.1 micron to 300 microns, which means that the minor diameter and major diameter of the particle are both within the range of 0.1 micron to 300 microns. Specifically, the particle size (major diameter or minor diameter) of the particle can be 0.1 micron to 280 microns, 1 micron to 250 microns, 3 microns to 230 microns, 5 microns to 200 microns, 7 microns to 180 microns, 10 microns to 150 microns, 13 microns to 130 microns, 15 microns to 100 microns, 20 microns to 80 microns, 23 microns to 70 microns, 26 microns to 50 microns, 30 microns to 40 microns, or a value between any two of the above end values.

[0075] In the embodiments of the present application, the shapes of the particles dispersed in the substrate may be the same or different; the sizes of the particles dispersed in the substrate may be the same or different; the particles dispersed in the substrate may be particles of the same material or particles of different materials.

[0076] In the embodiment of the present application, the particles may be uniformly dispersed on the surface of the film, or uniformly dispersed at various locations of the film.

[0077] like Figure 1 As shown, the embodiment of the present application also provides another optical film 10, which includes a substrate 11 and particles 12 dispersed in the substrate 11. 3 The number of particles 12 is greater than zero and less than or equal to 100, that is, the unit volume (μm 3 ) The number of particles R2 in the unit volume is greater than 0 and less than or equal to 0.01. The ratio of the number of particles R2 in the unit volume to the haze H of the optical film 10 is defined as ξ2, which is greater than zero and less than or equal to 100.

[0078] Doping the optical film 10 with particles can improve the chromaticity and viewing angle of the optical film 10 when applied to a display device. However, the addition of particles can increase haze, affecting transmittance. The inventors have also discovered that adding particles within a certain range of values can worsen the rainbow pattern of the optical film 10. The optical film 10 provided in the embodiments of the present application, by designing the number of particles R2 per unit volume and the value of ξ2 (R2 / H) within the aforementioned ranges, can not only reduce the difference between the in-plane retardation value and the retardation value in the thickness direction of the optical film 10, thereby improving the rainbow pattern phenomenon, but also has excellent mechanical properties. It can also improve the chromaticity and viewing angle of the optical film 10 when applied to a display device while maintaining a high transmittance.

[0079] In an embodiment of the present application, the haze H of the optical film 10 is greater than or equal to 0.01% and less than or equal to 20%. Within this range, it can effectively improve the rainbow stripe phenomenon and enhance the mechanical properties while ensuring the transmittance. Specifically, in an embodiment of the present application, the in-plane retardation value of the optical film 10 is less than or equal to 3000 nanometers, and the thickness direction retardation value of the optical film 10 is less than or equal to 6000 nanometers. The in-plane retardation value refers to the retardation value in the plane where the optical film 10 is located, and the thickness direction retardation value refers to the retardation value in the direction perpendicular to the plane where the optical film 10 is located. By designing the number of particles R2, the haze H and the ξ2 value per unit volume within the above range, the present application can reduce the in-plane retardation value of the optical film 10 so that the difference between the in-plane retardation value and the thickness direction retardation value is within a smaller range, thereby improving the rainbow stripe phenomenon.

[0080] In the embodiment of the present application, the in-plane retardation value and the thickness direction retardation value of the optical film 10 can be calculated according to the following formula:

[0081] Re=(n x -n y )d;

[0082]

[0083] Where Re is the in-plane retardation value, Rth is the thickness direction retardation value, d is the thickness of the optical film, and n is the thickness of the optical film. x is the refractive index in the slow axis direction (the direction with the largest refractive index) in the plane where the optical film is located, n y is the refractive index of the fast axis direction (the direction with the smallest refractive index) in the plane where the optical film is located, n z It is the refractive index in the direction perpendicular to the plane where the optical film is located, and the slow axis direction and the fast axis direction are orthogonal to each other.

[0084] In the embodiment of the present application, the slow axis refractive index n of the optical film 10 of the present application can be made to be 100 μm by designing the number of particles R2, haze H and ξ2 value per unit volume. x and the fast axis refractive index n y The difference is less than or equal to 0.15, which reduces the refractive index difference of the optical film 10 in different directions and improves the rainbow phenomenon.

[0085] The optical film 10 can be made by slicing the substrate 11, mechanically mixing the sliced substrate with particles, melt co-extrusion, casting, stretching, etc. By matching the number of particles per unit volume R2, haze H and ξ2 value, the breaking strength of the optical film 10 of the present application can reach 10N / mm 2 Up to 500N / mm 2 , has excellent resistance to tensile failure, the elongation at break can reach the range of 10% to 200%, and has excellent plastic deformation ability. Furthermore, the optical film 10 provided in the present application has excellent tensile properties.

[0086] In some embodiments, the intrinsic viscosity of the sliced substrate 11 after mechanical mixing with the particles can be controlled to be between 0.35 and 0.95. Accordingly, the optical film 10 can be characterized by a melt index, which is between 0.35 and 0.55. Within this range, the mechanical properties of the optical film 10 can be further improved. In the embodiments of the present application, the melt index can be measured using a melt index meter such as an XNR 400, in accordance with ASTM D 1238.

[0087] There is a certain degree of inverse relationship between the melt index of the film and the intrinsic viscosity of the slice. The intrinsic viscosity will affect the tensile / mechanical properties of the formed film. The higher the intrinsic viscosity of the slice, the better the tensile properties of the formed film and the better the mechanical properties. That is, if the melt index of the optical film 10 is small, the mechanical properties of the optical film 10 will be relatively better. Optionally, the melt index of the optical film 10 can be 0.38-0.55, 0.38-0.48, 0.45-0.48, or a value between any two ends of the above values. Within this range, while maintaining the excellent mechanical properties of the optical film 10, the difference in the retardation value of the optical film 10 in different directions can be reduced, thereby improving the rainbow pattern phenomenon.

[0088] In some embodiments, the crystallinity of the optical film 10 can be controlled between 15% and 35%. The crystallinity of the optical film 10 affects the optical transmittance, haze, mechanical properties, and retardation value of the film. By controlling the crystallinity of the optical film 10 within this range, it is possible to reduce optical loss while reducing the difference in retardation values of the optical film 10 in different directions, thereby improving the rainbow pattern phenomenon. In the embodiments of the present application, the crystallinity can be measured by DSC (differential scanning calorimetry), specifically using a DSC 3500 Sirius differential scanning calorimeter.

[0089] Optionally, the crystallinity of the optical film 10 may be 15% to 25%, 19% to 25%, 19% to 22%, 17% to 21% or any value between the two ends of the above values. Controlling the crystallization within this range can not only ensure high transmittance, but also reduce the difference in the delay value of the optical film 10 in different directions over a large length, thereby improving the rainbow pattern phenomenon.

[0090] In some embodiments, the unit volume (μm 3 ) may be less than or equal to 0.008; further, may be less than or equal to 0.006; further, may be less than or equal to 0.004.

[0091] In some embodiments, the haze H may be less than or equal to 15%, further, less than or equal to 8%, further, less than or equal to 6%, and further, less than or equal to 2%.

[0092] In some embodiments, the unit volume (μm 3 ) and the haze H may be greater than or equal to 0.1 and less than or equal to 0.4.

[0093] Optionally, in some embodiments, the number of particles per 10,000 cubic microns may be 20 to 40, that is, per unit volume (μm 3) can be greater than or equal to 0.002 and less than or equal to 0.004, the haze H can be greater than or equal to 1% and less than or equal to 2%, and ξ2 can be greater than or equal to 0.1 and less than or equal to 0.4. Within the above design range, the in-plane retardation value of the optical film 10 is less than or equal to 190 nanometers, and the thickness direction retardation value is less than or equal to 500 nanometers, which can further reduce the difference between the in-plane retardation value and the thickness direction retardation value, and further effectively improve the rainbow pattern. Within the above design range, the slow axis refractive index n of the optical film 10 is less than or equal to 190 nanometers, and the thickness direction retardation value is less than or equal to 500 nanometers. x and the fast axis refractive index n y The difference between them can be controlled to be 0.003 and less than or equal to 0.007, which effectively reduces the anisotropy of the refractive index of the optical film 10, reduces the interference of light, and thus improves the rainbow phenomenon.

[0094] In some embodiments, the substrate 11 of the optical film 10 has a glass transition temperature of 20°C to 600°C.

[0095] In some embodiments, the substrate 11 of the optical film 10 includes at least one of triacetyl cellulose (TAC), polyethylene terephthalate (PET), polycarbonate (PC), polymethyl methacrylate (PMMA), polycycloolefin (COP / COC), and polyethylene naphthalate (PEN). Alternatively, the substrate 11 of the optical film 10 may be a PET substrate. The substrate 11 may also be a mixed substrate of PET and PMMA.

[0096] In some embodiments, the thickness of the optical film 10 is 5 μm to 500 μm, specifically 5 to 50 μm, 10 to 60 μm, 30 to 80 μm, 5 to 450 μm, 10 to 400 μm, 20 to 350 μm, 30 to 300 μm, 40 to 250 μm, 45 to 200 μm, 50 to 150 μm, 60 to 120 μm, 65 to 100 μm, or a value between any two of the above end values.

[0097] In some embodiments, the particles dispersed within the substrate 11 may comprise less than 30% by weight of the optical film 10, specifically 0.1%, 0.5%, 0.8%, 1%, 2%, 3%, 5%, 8%, 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, or any value in between. Controlling the particle content within this range can balance the film's crystallinity, melt index, haze, and transmittance.

[0098] In some embodiments, the material of the particles 12 may include at least one of modified or unmodified inorganic substances and modified or unmodified organic substances. Inorganic substances may include, but are not limited to, silicon dioxide (SiO2), silicon carbide (SiC), silicon nitride (Si3N4), zinc oxide (ZnO2), magnesium oxide (MgO), aluminum oxide (Al2O3), calcium sulfate (CaSO4), calcium carbonate (CaCO3), potassium titanate (K6TiO4), and the like. 13 O6), aluminum borate (Al 18 B4O 33 ); the organic material may include, but is not limited to, at least one of polymethyl methacrylate (PMMA), polystyrene (PS), silicone, polybutyl acrylate-styrene, and poly-4-hydroxybenzyl ester. The above-mentioned particle materials may be surface-modified.

[0099] In some embodiments, the shape of the particle 12 may include at least one of a spherical shape and a non-spherical shape. Specifically, the shape of the particle includes, but is not limited to, at least one of a sphere, an ellipsoid, a cube, a cuboid, a cone, a cylinder, a prism, a sheet, a single needle (rod), a three-needle shape, a four-needle shape, a petal shape, a disk shape, and a spiral shape.

[0100] In some embodiments, the particle size of the particle 12 is 0.1 micron to 300 microns. When the shape of the particle is non-spherical, the particle size of the particle is 0.1 micron to 300 microns, which means that the minor diameter and major diameter of the particle are both within the range of 0.1 micron to 300 microns. Specifically, the particle size (major diameter or minor diameter) of the particle can be 0.1 micron to 280 microns, 1 micron to 250 microns, 3 microns to 230 microns, 5 microns to 200 microns, 7 microns to 180 microns, 10 microns to 150 microns, 13 microns to 130 microns, 15 microns to 100 microns, 20 microns to 80 microns, 23 microns to 70 microns, 26 microns to 50 microns, 30 microns to 40 microns, or a value between any two of the above end values.

[0101] In the embodiments of the present application, the shapes of the particles dispersed in the substrate may be the same or different; the sizes of the particles dispersed in the substrate may be the same or different; the particles dispersed in the substrate may be particles of the same material or particles of different materials.

[0102] In the embodiment of the present application, the particles can be uniformly dispersed on the surface of the film, or uniformly dispersed inside the film. Figure 2 As shown, based on the above embodiments, the present application also provides a polarizer 100, comprising the optical film 10 in any of the above embodiments, and a polarizing layer 20. The absorption axis of the polarizing layer 20 is perpendicular to the slow axis direction of the optical film 10.

[0103] In some embodiments, the polarizing layer 20 may be a PVA (polyvinyl alcohol) film layer.

[0104] In some embodiments, the polarizer 100 further includes an optically functional layer 30 located on the side of the optical film 10 facing away from the polarizing layer 20. The optically functional layer 30 may be a single layer structure or a composite multilayer structure. The optically functional layer includes, but is not limited to, at least one of an anti-glare layer, a hard coating layer, an anti-reflection layer, a low-reflection layer, an anti-fingerprint layer, and an antistatic layer. For example, the optically functional layer may be a laminated structure of a hard coating layer and an anti-reflection layer.

[0105] The hard coating layer is highly hard and water- and oil-resistant, effectively preventing scratches on the underlying film layer and making it easier to clean. Optionally, the hard coating layer has a high glass transition temperature, for example, between 70°C and 120°C. The hard coating layer can be made of at least one of polyurethane resin, acrylate resin, epoxy resin, vinyl resin, and silicone resin.

[0106] The anti-reflection layer is used to prevent reflection and also protect against scratches. The anti-reflection layer can be a dielectric film formed on the surface of the hard coat.

[0107] In some embodiments, the polarizer 100 further includes a release film 40, a pressure-sensitive adhesive layer 50, and an optical compensation layer 60 stacked in sequence. The polarizing layer 20, the optical film 10, and the optical functional layer 30 are stacked in sequence on the optical compensation layer 60.

[0108] The release film 40 protects the pressure-sensitive adhesive layer from damage and prevents bubbles from forming before the polarizer is attached to the display panel. The release film can be a polyester film, such as polyethylene terephthalate, a polyolefin film, such as polyethylene or polypropylene, or a polytetrafluoroethylene film. Alternatively, a release-treated film, such as a silicone resin, melamine resin, or urea resin, can be used to facilitate removal.

[0109] The pressure-sensitive adhesive layer 50 is used to bond the release film and the optical compensation layer disposed on the release film. The material of the pressure-sensitive adhesive layer can be, for example, an acrylic resin.

[0110] The optical compensation layer 60 may be a compensation layer or a retardation film in which a liquid crystal compound is coated on a substrate surface and aligned and fixed.

[0111] In some embodiments, a protective layer 70 is further provided on the optical functional layer 30. When the polarizer 100 is in use, the direction from the release film 40 to the protective layer 70 is the stacking direction of the film layers in the polarizer 100 and is also the incident direction of light.

[0112] The protective layer 70 is used to protect the film layer thereunder. The protective layer 70 can be a transparent resin film formed from a thermoplastic resin, such as a polyolefin resin such as a linear polyolefin resin (polypropylene resin, etc.), a cyclic polyolefin resin (norbornene resin, etc.), a cellulose ester resin such as cellulose triacetate and cellulose diacetate, a polyester resin such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate, a polycarbonate resin, a (meth)acrylic resin, or a mixture or copolymer thereof.

[0113] like Figure 3 As shown, an embodiment of the present application further provides a display device 1000, which includes an upper polarizer 100A, a lower polarizer 100B, and a display panel 200 located between the upper polarizer 100A and the lower polarizer 100B. The upper polarizer 100A is located on the light-emitting side of the display panel 200, and the lower polarizer 100B is located on the other side of the display panel 200 away from the light-emitting side.

[0114] In some embodiments, the display panel 200 may be a liquid crystal display panel. The structure of the liquid crystal display panel may refer to the prior art and will not be described in detail here.

[0115] In the embodiments of the present application, at least one of the upper polarizer 100A and the lower polarizer 100B can adopt the structure of the polarizer 100 in the above embodiment. When the polarizer 100 in the above embodiment is used as the upper polarizer 100A, the optical film 10 is disposed on the side of the polarizing layer 20 facing away from the display panel; when the polarizer 100 in the above embodiment is used as the lower polarizer 100A, the optical film 10 is disposed on the side of the polarizing layer 20 closer to the display panel 200.

[0116] The present application applies the polarizer 100 having the above-mentioned optical film 10 to the display device 1000, thereby improving the rainbow phenomenon and having excellent mechanical properties. At the same time, it can improve the chromaticity and viewing angle of the display device and maintain a high transmittance.

[0117] In some embodiments, the display device further includes a backlight module 300. The backlight module 300 may include a backlight source, which may be a direct backlight source or an edge backlight source.

[0118] The backlight module can be any type of backlight module, for example, it can be a quantum dot backlight module suitable for a high color gamut using quantum dots. Specifically, the backlight source may include light-emitting diodes distributed in an array and a color conversion layer. The light-emitting diodes may be blue light-emitting diodes. The color conversion layer is used to convert the light emitted by the blue light-emitting diodes into backlight of different colors. The color conversion layer may include a plurality of first color conversion units, a plurality of second color conversion units, a plurality of third color conversion units, and a plurality of fourth color conversion units. The first color conversion unit may include yellow phosphor, the second color conversion unit may include green phosphor, the third color conversion unit may include red phosphor and green phosphor, and the fourth color conversion unit may include red fluorescent quantum dot material, green fluorescent quantum dot material, and blue fluorescent quantum dot material.

[0119] In some embodiments, the display device may be a VA (Vertical Alignment) mode liquid crystal display device or an IPS (In-Plane Switching) mode liquid crystal display device, and the liquid crystal may be a chiral liquid crystal having an in-plane retardation value of 300 nm to 500 nm.

[0120] The performance of the optical film provided in this application is verified through the following specific examples.

[0121] Example 1

[0122] First, the PET substrate is sliced and then mechanically mixed with calcium carbonate particles. The particles are in the shape of cubes with a long diameter of 2 microns, a short diameter of 2 microns, and a mass content of 0.10%. Then, the melt extrusion process is used to cast the sheets, followed by film casting in a film forming system. The film-formed substrate is then stretched (with a longitudinal stretching ratio of 3 times and a transverse stretching ratio of 2 times) to obtain an optical film with a thickness of 40 microns. The haze H of the optical film is 3%, and the unit area (μm 2 The number of particles dispersed in the top view pattern of the optical film is R1, which is 0.0019, ξ1(R1 / H) is 0.063, and the unit volume of the optical film (μm 3 )The number of particles R2 is 0.0026, and ξ2(R2 / H) is 0.087.

[0123] Example 2

[0124] This embodiment is basically the same as the embodiment 1, except that the mass content of the particles is 0.50%, the haze H is 4%, R1 is 0.015, R2 is 0.013, and accordingly, ξ1 is 0.375 and ξ2 is 0.325.

[0125] Example 3

[0126] This embodiment is basically the same as the embodiment 1, except that the mass content of the particles is 0.88%, the haze H is 6%, R1 is 0.027, and R2 is 0.023. Accordingly, ξ1 is 0.450 and ξ2 is 0.383.

[0127] Example 4

[0128] This embodiment is basically the same as the embodiment 1, except that the particles are spherical in shape, with a diameter of 2 microns, a haze H of 4%, and an R1 of 0.0038. Accordingly, ξ1 is 0.095 and ξ2 is 0.065.

[0129] Example 5

[0130] This embodiment is basically the same as the embodiment 1, except that the particles are rod-shaped, with a major diameter of 20 μm and a minor diameter of 2 μm, a haze H of 5%, and an R1 of 0.0033. Accordingly, ξ1 is 0.066 and ξ2 is 0.052.

[0131] Example 6

[0132] This embodiment is essentially the same as Example 1, differing only in that the substrate is replaced with a mixed substrate of PET and PMMA, with PET accounting for 5% by mass and PMMA accounting for 95% by mass. R1 is 0.0033. Accordingly, ξ1 is 0.110 and ξ2 is 0.08.

[0133] Example 7

[0134] This embodiment is essentially the same as Example 1, differing only in that the substrate is replaced with a mixed substrate of PET and PMMA, with PET accounting for 50% by weight and PMMA accounting for 50% by weight. The haze H is 2%, and R1 is 0.0033. Accordingly, ξ1 is 0.165, and ξ2 is 0.13.

[0135] Example 8

[0136] This embodiment is essentially the same as Example 1, differing only in that the substrate is replaced with a mixed substrate of PET and PMMA, with PET accounting for 95% by mass and PMMA accounting for 5% by mass. The haze H is 1%, and R1 is 0.0033. Accordingly, ξ1 is 0.330, and ξ2 is 0.26.

[0137] Example 9

[0138] The scheme of this embodiment is basically the same as that of embodiment 1, except that the haze H is 12%, R1 is 0.04, and R2 is 0.035. Accordingly, ξ1 is 0.333, and ξ2 is 0.29.

[0139] Example 10

[0140] The scheme of this embodiment is basically the same as that of embodiment 1, except that the haze H is 1%, R1 is 0.001, and R2 is 0.0007. Accordingly, ξ1 is 0.100 and ξ2 is 0.07.

[0141] Example 11

[0142] The scheme of this embodiment is basically the same as that of embodiment 1, except that the haze H is 2%, R1 is 0.02, and R2 is 0.016. Accordingly, ξ1 is 1.00 and ξ2 is 0.80.

[0143] Example 12

[0144] The scheme of this embodiment is basically the same as that of embodiment 1, except that the haze H is 2%, R1 is 0.025, and R2 is 0.027. Accordingly, ξ1 is 1.250, and ξ2 is 1.35.

[0145] Example 13

[0146] The scheme of this embodiment is basically the same as that of embodiment 1, except that the haze H is 2%, R1 is 0.03, and R2 is 0.029. Accordingly, ξ1 is 1.500 and ξ2 is 1.45.

[0147] Example 14

[0148] This embodiment is basically the same as the embodiment 1, except that the haze H is 0.04%, R1 is 0.034, and R2 is 0.025. Accordingly, ξ1 is 84 and ξ2 is 62.5.

[0149] Example 15

[0150] This embodiment is basically the same as the embodiment 1, except that the haze H is 0.02%, R1 is 0.0098, and R2 is 0.087. Accordingly, ξ1 is 49 and ξ2 is 43.5.

[0151] Example 16

[0152] This embodiment is basically the same as the embodiment 1, except that the haze H is 0.05%, R1 is 0.01, and R2 is 0.0095. Accordingly, ξ1 is 20 and ξ2 is 19.

[0153] Comparative Example 1

[0154] This comparative example is basically the same as Example 1, except that no particles are added and the haze H is 0.2%. Accordingly, ξ1 is 0 and ξ2 is 0.

[0155] Comparative Example 2

[0156] This comparative example is basically the same as Example 1, except that the major diameter of the particles is 20 μm, the minor diameter is 20 μm, the haze H is 4%, R1 is 0.085, and R2 is 0.1. Accordingly, ξ1 is 2.125 and ξ2 is 2.5.

[0157] Comparative Example 3

[0158] This comparative example is basically the same as Example 1, except that the major diameter of the particles is 20 μm, the minor diameter is 20 μm, the haze H is 18%, R1 is 0.95, and R2 is 1. Accordingly, ξ1 is 5.278 and ξ2 is 5.6.

[0159] Comparative Example 4

[0160] This comparative example is essentially the same as Example 1, except that the particle length is 20 μm, the short diameter is 20 μm, the haze H is 5%, R1 is 0.045, and R2 is 0.056. Accordingly, ξ1 is 0.900 and ξ2 is 1.12.

[0161] The main parameters of the optical films prepared in Examples 1-16 and Comparative Examples 1-4 are shown in Table 1 below.

[0162] Table 1

[0163]

[0164] The optical films of Examples 1-16 and Comparative Examples 1-4 were subjected to performance tests, and the test results are shown in Table 2 below.

[0165] Table 2

[0166]

[0167] According to the comparison between the above-mentioned Examples 1-16 and Control Examples 1-4, it can be seen that the optical film prepared in Example 1-16 has a better effect of improving rainbow stripes than the optical film prepared in Control Examples 1-4. The possible reason is that the in-plane delay value and the thickness direction delay value of the optical film prepared in Example 1-16 are both smaller, which reduces the difference between the in-plane delay value and the thickness direction value, thereby facilitating the improvement of rainbow stripes.

[0168] According to the comparison between Example 1 and Example 6, the optical film prepared in Example 1 has better comprehensive performance than the optical film prepared in Example 6, such as tensile properties, the ability to improve the difference between in-plane retardation values and thickness direction retardation values. The possible reason is that the tensile properties and refractive index anisotropy of the PET substrate are better than those of the PMMA substrate.

[0169] A comparison of Examples 1-3, 11-13 with Examples 4-5 shows that, given a relatively small difference in haze values, the optical films prepared in Examples 1-3 and 11-13 exhibit superior overall performance, including tensile properties and the ability to improve the difference between in-plane retardation and thickness-direction retardation, compared to the optical film prepared in Example 4. In terms of these overall properties, cubic particles outperform spherical particles.

[0170] According to the comparison between the above-mentioned Example 1 and the control examples 2-3, it can be seen that the optical film prepared in Example 1 has a significant effect of improving rainbow patterns compared with the optical films prepared in the control examples 2-3. The possible reason is that particles with relatively small particle sizes are doped in the optical film, which is more conducive to reducing the difference between the in-plane delay value and the thickness direction delay value.

[0171] According to the comparison between the above-mentioned Examples 1-3, 11-13 and Examples 9-10, 14-16, it can be seen that the optical films prepared in Examples 1-3, 11-13 are better than those in Examples 9, 14-16 in improving the difference between the in-plane retardation value and the thickness direction retardation value. The possible reason is that the haze value is too high or too low, which is not conducive to improving the difference between the in-plane retardation value and the thickness direction retardation value.

[0172] According to the comparison between the above-mentioned Examples 1-2 and other examples, it can be seen that the optical films prepared in Examples 1-2 have better overall performance in terms of tensile properties, improved rainbow patterns, transmittance, etc. The possible reason is that by controlling the crystallinity of the optical film to 17% to 21% and the melt index of the optical film to 0.45 to 0.48, the difference between the in-plane delay value and the thickness direction delay value can be significantly reduced while improving the mechanical properties and optical transmittance of the optical film.

[0173] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0174] The above is a detailed introduction to an optical film, a polarizer and a display device provided in the embodiments of the present application. 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 technical solutions and core ideas of the present application. Ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. An optical film, characterized in that: include: substrate; as well as particles dispersed in the substrate; Among them, at the top-view angle of the optical film, the number of particle top-view patterns dispersed in every 10,000 square microns of the optical film top-view pattern is greater than 0 and less than or equal to 400, and the ratio of the number of the particle top-view patterns dispersed in every square micron of the optical film top-view pattern to the haze of the optical film is greater than zero and less than or equal to 100.

2. The optical film according to claim 1, wherein At a top-view angle of the optical film, the number of the particle top-view patterns dispersed within every 10,000 square microns of the optical top-view pattern is greater than 10 and less than 300, and the ratio of the number of the particle top-view patterns dispersed within every square micron of the optical film top-view pattern to the haze of the optical film is greater than 0 and less than 20.

3. The optical film according to claim 1, wherein The number of the particles dispersed per 10,000 cubic microns of the optical film is greater than 0 and less than or equal to 300, and the ratio of the number of the particles dispersed per cubic micron to the haze is greater than 0 and less than or equal to 100.

4. The optical film according to claim 3, wherein In a top-view angle of the optical film, the number of the particle top-view patterns dispersed within every 10,000 square micrometers of the optical film top-view pattern is greater than 10 and less than 300, and the ratio of the number of the particle top-view patterns dispersed within every square micrometer of the optical film top-view pattern to the haze of the optical film is greater than 0 and less than 20; The number of the particles dispersed per 10,000 cubic microns of the optical film is greater than or equal to 20 and less than 300, and the ratio of the number of the particles dispersed per cubic micron to the haze is greater than 0 and less than or equal to 20.

5. The optical film according to any one of claims 1 to 4, characterized in that The haze is greater than zero and less than 100%.

6. The optical film according to claim 5, wherein The haze is greater than or equal to 0.01% and less than or equal to 20%.

7. The optical film according to claim 6, wherein The in-plane retardation value of the optical film is less than or equal to 3000 nanometers, and the thickness direction retardation value of the optical film is less than or equal to 6000 nanometers.

8. The optical film according to claim 6, wherein A difference between a slow-axis refractive index of the optical film and a fast-axis refractive index of the optical film is less than or equal to 0.

15.

9. The optical film according to claim 6, wherein The breaking strength of the optical film is 10N / mm 2 Up to 500N / mm 2 , the elongation at break is 10% to 200%.

10. The optical film according to claim 9, wherein The breaking strength of the optical film is 50N / mm 2 Up to 350N / mm 2 , the elongation at break is 30% to 200%.

11. The optical film according to claim 4, wherein In a top-view angle of the optical film, the number of the particle top-view patterns dispersed within every 10,000 square micrometers of the optical film top-view pattern is greater than 10 and less than 300, and the ratio of the number of the particle top-view patterns dispersed within every square micrometer of the optical film top-view pattern to the haze of the optical film is greater than or equal to 0 and less than or equal to 2; The number of the particles dispersed in every 10,000 cubic microns of the optical film is greater than or equal to 20 and less than or equal to 300, the haze is greater than or equal to 1% and less than or equal to 6%, and the ratio of the number of the particles dispersed in every cubic micron to the haze is greater than or equal to 0 and less than or equal to 2.

12. The optical film according to claim 11, wherein The in-plane retardation value of the optical film is less than or equal to 190 nanometers, and the thickness direction retardation value of the optical film is less than or equal to 500 nanometers.

13. The optical film according to claim 11, wherein A difference between a slow-axis refractive index of the optical film and a fast-axis refractive index of the optical film is greater than or equal to 0.003 and less than or equal to 0.

007.

14. The optical film according to claim 1, wherein The melt index of the optical film is greater than or equal to 0.35 and less than or equal to 0.55; And / or, the crystallinity of the optical film is greater than or equal to 15% and less than or equal to 35%.

15. The optical film according to claim 1, wherein The substrate includes but is not limited to cellulose triacetate, polyethylene terephthalate, polycarbonate, polymethyl methacrylate, polycycloolefin, polyethylene naphthalate; and / or The shape of the particles includes at least one of a sphere, an ellipsoid, a cube, a cuboid, a cone, a cylinder, a prism, a sheet, a single needle, a three-needle, a four-needle, a petal, a disc, and a spiral; and / or The material of the particles includes at least one of polymethyl methacrylate, polystyrene, organosilicon, polybutyl acrylate-styrene, poly-4-hydroxybenzyl ester, silicon dioxide, silicon carbide, silicon nitride, zinc oxide, magnesium oxide, aluminum oxide, calcium sulfate, calcium carbonate, potassium titanate, and aluminum borate.

16. The optical film according to claim 1, wherein The particles account for less than 30% of the mass of the optical film; and / or The thickness of the optical film is 5 μm to 500 μm; and / or The particle size of the particles is greater than or equal to 0.1 micrometer and less than or equal to 300 micrometers; and / or The glass transition temperature of the substrate is 20°C to 600°C.

17. A polarizer, characterized in that: The optical film comprises a polarizing layer and an optical film, wherein the optical film is the optical film according to any one of claims 1 to 16, and a slow axis direction of the optical film is perpendicular to an absorption axis of the polarizing layer.

18. The polarizer according to claim 17, wherein: The polarizer further includes an optical functional layer located on a side of the optical film away from the polarizing layer, and the optical functional layer includes at least one of an anti-glare layer, a hard coating layer, an anti-reflection layer, a low-reflection layer, an anti-fingerprint layer, and an antistatic layer.

19. A display device, characterized in that: It comprises the polarizer and display panel as claimed in claim 17 or 18.

Images