Optical film, polarizer and display device

Abstract

An optical film (10), a polarizer (100) and a display device (1000). The optical film (10) comprises a matrix (11) and particles (12) dispersed in the matrix (11), wherein the number of the particles per ten thousand cubic micrometers in the optical film (10) is smaller than or equal to 100, and the ratio of the number (R) of the particles per cubic micrometer to the haze (H) of the optical film (10) is larger than zero and smaller than or equal to 100.

Description

Optical film, polarizing sheet and display device

[0001] This application claims priority to Chinese Patent Application No. 202411103986.5, filed on August 12, 2022, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0002] The present application belongs to the technical field of display, and in particular relates to an optical film, a polarizing sheet and a display device. BACKGROUND

[0003] Polarizing sheets have a wide range of applications in the field of display. Generally, an optical film is used to protect the polarizing layer of the polarizing sheet. However, since the optical film usually has birefringence, the refractive index of the optical film is anisotropic, and the light transmitted through the optical film will be decomposed into ordinary light and extraordinary light with a certain retardation value. If the retardation values of the two kinds of light exceed a certain range, interference of light will occur, thereby forming rainbow stripes, which will reduce the display quality when the polarizing sheet is applied to a display device.

[0004] In addition, in order to improve the chroma color angle of display, diffusion particles are added to the optical film. However, the inventors have found that the addition of diffusion particles to a certain range will adversely affect the in-plane retardation value of the optical film, resulting in a too large difference between the in-plane retardation value and the thickness direction retardation value, and causing deterioration of rainbow stripes. SUMMARY

[0005] Embodiments of the present application provide an optical film, a polarizing sheet and a display device to solve the technical problem that the addition of a certain amount of diffusion particles to the existing optical film will cause the risk of deterioration of rainbow stripes.

[0006] In a first aspect, embodiments of the present application provide an optical film, comprising a substrate and particles dispersed in the substrate; wherein the number of particles dispersed in each 10,000 cubic microns of the optical film is greater than 0 and less than or equal to 100, and the ratio of the number of particles dispersed in each cubic micrometer to the haze is greater than 0 and less than or equal to 100.

[0007] In a second aspect, embodiments of the present application also provide a polarizing sheet, comprising a polarizing layer and the optical film of any of the above embodiments, wherein the slow axis direction of the optical film and the slow axis direction of the optical functional layer are perpendicular to the absorption axis of the polarizing layer.

[0008] In a third aspect, embodiments of the present application also provide a display device, comprising the polarizing sheet of any of the above embodiments and a display panel. BRIEF DESCRIPTION OF DRAWINGS

[0009] In order to more clearly illustrate the technical solutions in the embodiments or the prior art, the following will briefly introduce the drawings needed to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description only represent some of the embodiments of the application, and for those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0010] Fig. 1 is a structural schematic diagram of an optical film provided by an embodiment of the application.

[0011] Fig. 2 is a structural schematic diagram of a polarizer provided by an embodiment of the application.

[0012] Fig. 3 is a structural schematic diagram of a display device provided by an embodiment of the application. Embodiment of the application

[0013] The technical solutions in the embodiments of the application will be described clearly and completely in the following with reference to the drawings in the embodiments of the application. Obviously, the described embodiments only represent some of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative effort fall within the scope of protection of the application.

[0014] In the description of the application, it should be understood that the terms "thickness", "upper", "lower" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the application.

[0015] The following disclosure provides many different embodiments or examples for implementing different structures of the application. In order to simplify the disclosure of the application, the components and settings of a specific example are described in the following. Of course, they are only examples, and the purpose is not to limit the application. In addition, the application can repeatedly refer to the same reference numerals and / or reference letters in different examples. Such repetition is for the purpose of simplification and clarity, and does not in itself indicate a relationship between the various embodiments and / or settings discussed. In addition, the application provides examples of various specific processes and materials, but those skilled in the art can realize the application of other processes and / or the use of other materials.

[0016] The application is directed to the existing optical film. In order to improve the chroma color angle of the display, particles are added to the optical film, but after the amount of diffusing particles is added to a certain range, it will adversely affect the in-plane retardation value of the optical film, resulting in too large difference between the in-plane retardation value and the thickness direction retardation value, causing the rainbow stripe to deteriorate. The present embodiment is proposed to overcome this defect.

[0017] As shown in FIG. 1, the present application provides an optical film 10, which comprises a substrate 11 and particles 12 dispersed in the substrate 11. The number of particles 12 in the optical film 10 per 10000 μm 3 is greater than zero and less than or equal to 100, i.e. the number of particles R in unit volume (μm 3 ) is greater than 0 and less than or equal to 0.01. The number of particles R in unit volume and the haze H of the optical film 10 are defined as ξ, which is greater than zero and less than or equal to 100.

[0018] The doping of particles in the optical film 10 can improve the chromaticity viewing angle when the optical film 10 is applied to a display device, but the addition of particles will increase the haze, affecting the transmittance. The inventors have found that when the number of particles is added to a certain range of values, the rainbow stripe of the optical film 10 will be deteriorated. The optical film 10 provided in the present application can not only reduce the difference between the in-plane retardation value and the thickness direction retardation value of the optical film 10, improve the rainbow stripe phenomenon, but also has excellent mechanical properties, while improving the chromaticity viewing angle when the optical film 10 is applied to a display device, and maintaining a high transmittance, by designing the number of particles R in unit volume and the value of ξ (R / H) within the above range.

[0019] In the embodiments 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, the rainbow stripe phenomenon and the mechanical properties can be effectively improved, and the transmittance can be guaranteed. Specifically, in the embodiments of the present application, the in-plane retardation value of the optical film 10 is less than or equal to 3000 nm, and the thickness direction retardation value of the optical film 10 is less than or equal to 6000 nm. The in-plane retardation value refers to the retardation value in the plane of the optical film 10, and the thickness direction retardation value refers to the retardation value in the direction perpendicular to the plane of the optical film 10. By designing the number of particles R in unit volume, the haze H and the value of ξ 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.

[0020] In the embodiments 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:

[0021] ;

[0022] ;

[0023] wherein Re is the in-plane retardation value, Rth is the thickness direction retardation value, d is the thickness of the optical film, n x is the refractive index in the slow axis direction (the direction with large refractive index) in the plane of the optical film, and n yn is the refractive index in the fast axis direction (the direction with a small refractive index) in the plane in which the optical film is located z n is the refractive index in the direction perpendicular to the plane in which the optical film is located, the slow axis direction and the fast axis direction are orthogonal.

[0024] In the embodiments of the present application, by matching the particle number R in the unit volume, the haze H, and the ξ value, the slow axis refractive index n x of the optical film 10 of the present application is less than or equal to 0.15, the difference in refractive index of the optical film 10 in different directions is reduced, and the rainbow phenomenon is improved. y

[0025] The optical film 10 can be made by slicing the substrate 11, mechanically mixing the sliced substrate with particles, melt co-extrusion, casting film formation, stretching, etc. By matching the particle number R in the unit volume, the haze H, and the ξ value, the breaking strength of the optical film 10 of the present application can reach 10 N / mm 2 to 500 N / mm 2 , has excellent resistance to tensile failure, and the elongation at break can reach 10% to 200%, has excellent plastic deformation capacity, and further, the optical film 10 provided by the present application has excellent tensile properties.

[0026] In some embodiments, the intrinsic viscosity of the sliced substrate after mechanically mixing with particles can be controlled to be between 0.35 and 0.95. Accordingly, in the optical film 10, the melt index can be used as a representation, and the melt index of the optical film 10 is 0.35 to 0.55, which can further improve the mechanical properties of the optical film 10. In the embodiments of the present application, the melt index can be tested by XNR 400 melt indexer, and the execution standard is ASTM D 1238.

[0027] There is an inverse relationship between the melt index of the film and the intrinsic viscosity of the sliced substrate to a certain extent. The intrinsic viscosity affects the tensile / mechanical properties of the formed film, the higher the intrinsic viscosity of the sliced substrate, the better the tensile properties and the mechanical properties of the formed film, that is, the smaller the melt index of the optical film 10, the relatively better the mechanical properties of the optical film 10. Alternatively, the melt index of the optical film 10 can be 0.38 to 0.55, 0.38 to 0.48, 0.45 to 0.48, or a value between any two of the above end values, within this range, the excellent mechanical properties of the optical film 10 can be maintained, while the retardation value difference of the optical film 10 in different directions is reduced, and the rainbow phenomenon is improved.

[0028] ​In some embodiments, the optical film 10 can have a crystallinity of 15% to 35%. The crystallinity of the optical film 10 can affect the optical transmittance, haze, mechanical properties, and retardation of the film. By controlling the crystallinity of the optical film 10 within this range, the optical loss can be reduced, and the difference in retardation of the optical film 10 in different directions can be reduced, thereby improving the rainbow phenomenon. In embodiments of the present application, the crystallinity can be measured by a DSC (Differential Scanning Calorimetry) method, and specifically, can be measured by a DSC 3500 Sirius Differential Scanning Calorimeter.

[0029] Alternatively, the optical film 10 can have a crystallinity of 15% to 25%, 19% to 25%, 19% to 22%, 17% to 21%, or a value between any two of the above-mentioned ranges. Controlling the crystallinity within this range can ensure high transmittance, and can reduce the difference in retardation of the optical film 10 in different directions over a large length, thereby improving the rainbow phenomenon.

[0030] In some embodiments, the number of particles R per unit volume (μm 3 ) can be less than or equal to 0.008; further, can be less than or equal to 0.006; further, can be less than or equal to 0.004.

[0031] In some embodiments, the haze H can be less than or equal to 15%; further, can be less than or equal to 8%; further, can be less than or equal to 6%; further, can be less than or equal to 2%.

[0032] Alternatively, in some embodiments, the number of particles per ten million cubic microns can be 20 to 40, i.e., the number of particles R 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 the ξ can be greater than or equal to 0.1 and less than or equal to 0.4. Within the above-mentioned design range, the in-plane retardation of the optical film 10 is less than or equal to 190 nm, the thickness-direction retardation is less than or equal to 500 nm, the difference between the in-plane retardation and the thickness-direction retardation can be further reduced, and the rainbow phenomenon can be further effectively improved. Within the above-mentioned design range, the difference between the slow-axis refractive index n x and the fast-axis refractive index n y of the optical film 10 can be controlled to be 0.003 and less than or equal to 0.007, the anisotropy of the refractive index of the optical film 10 can be effectively reduced, the light interference can be reduced, and the rainbow phenomenon can be improved.

[0033] In some embodiments, the glass transition temperature of the substrate 11 of the optical film 10 is 20°C to 600°C.

[0034] In some embodiments, the substrate 11 of the optical film 10 includes at least one selected from cellulose triacetate (TAC), polyethylene terephthalate (PET), polycarbonate (PC), polymethyl methacrylate (PMMA), polycyclic olefin (COP / COC), and polyethylene naphthalate (PEN). Optionally, the substrate 11 of the optical film 10 may be a PET substrate. The substrate 11 may also be a hybrid substrate of PET and PMMA.

[0035] In some embodiments, the thickness of the optical film 10 is from 5 micrometers to 500 micrometers, specifically from 5 micrometers to 450 micrometers, 10 micrometers to 400 micrometers, 20 micrometers to 350 micrometers, 30 micrometers to 300 micrometers, 40 micrometers to 250 micrometers, 45 micrometers to 200 micrometers, 50 micrometers to 150 micrometers, 60 micrometers to 120 micrometers, 65 micrometers to 100 micrometers, or any value between any two of the above endpoints.

[0036] In some embodiments, the particles dispersed in the substrate 11 account for less than 30% of the mass content 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 between two of the above endpoints. Controlling the particle mass content within this range can balance the crystallinity, melt index, haze, and transmittance of the film material.

[0037] In some embodiments, the material of particle 12 may include at least one of modified or unmodified inorganic materials and modified or unmodified organic materials. Inorganic materials 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), and potassium titanate (K6Ti). 13 O6), aluminum borate (Al) 18 B4O 33 At least one of the following: ; organic materials may include, but are not limited to, at least one of polymethyl methacrylate (PMMA), polystyrene (PS), organosilicon, polybutyl acrylate-styrene, and poly(4-hydroxybenzoyl) ester. The above-listed particulate materials may undergo surface modification treatment.

[0038] In some embodiments, the shape of the particle 12 may include at least one of spherical or non-spherical shapes. Specifically, the shape of the particle includes, but is not limited to, at least one of sphere, ellipsoid, cube, cuboid, cone, cylinder, frustum, plate, single needle (rod), three needle, four needle, petal, disc, and spiral.

[0039] In some embodiments, the particle 12 has a particle size of 0.1 microns to 300 microns. When the particle is non-spherical, the particle size of the particle, which is 0.1 microns to 300 microns, refers to the short diameter and the long diameter of the particle being in the range of 0.1 microns to 300 microns. Specifically, the particle size (long diameter or short diameter) of the particle can be 0.1 microns 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.

[0040] As shown in FIG. 2, based on the above embodiments, the present embodiments also provide a polarizer 100, which includes 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.

[0041] In some embodiments, the polarizing layer 14 can be a PVA (polyvinyl alcohol) film layer.

[0042] In some embodiments, the polarizer 100 further includes an optical functional layer 30 on the side of the optical film 10 away from the polarizing layer 20. The optical functional layer 30 can be a single-layer structure or a composite multi-layer structure. The optical 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, a fingerprint-resistant layer, and an anti-static layer. For example, the optical functional layer can be a stacked structure of a hard coating layer and an anti-reflection layer.

[0043] The hard coating layer has high hardness, water and oil resistance, and can effectively prevent the surface of the underlying film layer from being scratched and is easier to clean. Optionally, the hard coating has a high glass transition temperature, for example, 70 degrees Celsius to 120 degrees Celsius. The material of the hard coating layer can include at least one of a polyurethane resin, an acrylate resin, an epoxy resin, a vinyl resin, and a silicone resin.

[0044] The anti-reflection layer is used for anti-reflection and also prevents scratching. The anti-reflection layer can be an electret film formed on the surface of the hard coating layer.

[0045] 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.

[0046] The role of the release film 40 is to protect the pressure-sensitive adhesive layer from damage and avoid the generation of a bonding bubble before the polarizing plate is bonded to the display panel. The release film can be a polyester film such as a polyethylene terephthalate film, a polyolefin film such as a polyethylene film and a polypropylene film, or a polytetrafluoroethylene film, or a release-treated film of a silicone resin, a melamine resin, or a urea resin, etc. can be used so that the release film is easily peeled off.

[0047] The pressure-sensitive adhesive layer 50 is used to bond the release film to the optical compensation layer provided on the release film. The material of the pressure-sensitive adhesive layer can be, for example, an acrylate resin.

[0048] The optical compensation layer 60 can be a compensation layer in which a liquid-crystalline compound is coated on the surface of a substrate, oriented, and fixed, or a phase difference film, etc.

[0049] In some embodiments, a protective layer 70 is further provided on the optical functional layer 30. In the use state of the polarizing plate 100, the direction from the release film 40 to the protective layer 70 is the stacking direction of the film layers in the polarizing plate 100, and is also the incident direction of light.

[0050] The protective layer 70 is used to protect the film layers thereunder. The protective layer 70 can be a transparent resin film formed of a thermoplastic resin such as a chain polyolefin resin (a polypropylene resin, etc.), a cyclic polyolefin resin (a norbornene resin, etc.), a cellulose ester resin such as cellulose triacetate, cellulose diacetate, a polyester resin such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, a polycarbonate resin, a (meth)acrylic resin, or a mixture, copolymer, etc. thereof.

[0051] As shown in FIG. 3, the present application also provides a display device 1000, which includes an upper polarizing plate 100A, a lower polarizing plate 100B, and a display panel 200 between the upper polarizing plate 100A and the lower polarizing plate 100B. The upper polarizing plate 100A is located on the light-emitting side of the display panel 200, and the lower polarizing plate 100B is located on the side of the display panel 200 that is away from the light-emitting side.

[0052] In some embodiments, the display panel 200 can be a liquid crystal display panel, and the structure of the liquid crystal display panel can refer to the prior art, which will not be described here.

[0053] In the embodiments of the present application, at least one of the upper polarizing plate 100A and the lower polarizing plate 100B can adopt the structure of the polarizing plate 100 in the above-described embodiments. When the polarizing plate 100 of the above-described embodiments is used as the upper polarizing plate 100A, the optical film 10 is disposed on the side of the polarizing layer 20 away from the display panel; when the polarizing plate 100 of the above-described embodiments is used as the lower polarizing plate 100A, the optical film 10 is disposed on the side of the polarizing layer 20 close to the display panel 100.

[0054] By applying the polarizing plate 100 with the optical film 10 described above to the display device 1000, the present application can improve the rainbow stripe phenomenon, has excellent mechanical properties, and at the same time can improve the chroma viewing angle of the display device and maintain a high transmittance.

[0055] In some embodiments, the display device further comprises a backlight module 300. The backlight module 300 can comprise a backlight source, which can be a direct type backlight source or an edge type backlight source.

[0056] The backlight module can be any type of backlight module, for example, it can be a quantum dot type backlight module suitable for high color gamut using quantum dots. Specifically, the backlight source can comprise light emitting diodes distributed in an array and a color conversion layer. The light emitting diodes can 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, and the color conversion layer can comprise 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 can comprise yellow fluorescent powder, the second color conversion unit can comprise green fluorescent powder, the third color conversion unit can comprise red fluorescent powder and green fluorescent powder, and the fourth color conversion unit can comprise red fluorescent quantum dot material, green fluorescent quantum dot material, and blue fluorescent quantum dot material.

[0057] In some embodiments, the display device can 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 can be a chiral liquid crystal, and the in-plane retardation value of the chiral liquid crystal is 300 nanometers to 500 nanometers.

[0058] The performance of the optical film provided by the present application is verified by the following specific embodiments.

[0059] Embodiment 1

[0060] Firstly, the PET substrate is sliced, and the sliced PET substrate is mechanically mixed with calcium carbonate particles. The particles have a cubic shape, 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 a sheet, and then the sheet is formed into a film in a film forming system. The film is then stretched (the longitudinal stretching ratio is 3 times, and the transverse stretching ratio is 2 times) to obtain an optical film with a thickness of 40 microns. The number of particles R in a unit volume (μm 3 ) of the optical film is 0.0026, the haze H is 3%, and ξ(R / H) is 0.087.

[0061] Example 2

[0062] The scheme of this example is basically the same as that of Example 1, except that the mass content of the particles is 0.50%, the number of particles R in a unit volume is 0.013, and the haze H is 4%. Correspondingly, ξ is 0.325.

[0063] Example 3

[0064] The scheme of this example is basically the same as that of Example 1, except that the mass content of the particles is 0.88%, the number of particles R in a unit volume is 0.023, and the haze H is 6%. Correspondingly, ξ is 0.383.

[0065] Example 4

[0066] The scheme of this example is basically the same as that of Example 1, except that the shape of the particles is spherical, the diameter is 2 microns, and the haze H is 4%. Correspondingly, ξ is 0.065.

[0067] Example 5

[0068] The scheme of this example is basically the same as that of Example 1, except that the shape of the particles is rod-shaped, the long diameter is 20 microns, the short diameter is 2 microns, and the haze H is 5%. Correspondingly, ξ is 0.052.

[0069] Example 6

[0070] The scheme of this example is basically the same as that of Example 1, except that the substrate is replaced by a mixed substrate of PET and PMMA, the mass content of PET in the mixed substrate is 5%, the mass content of PMMA in the mixed substrate is 95%, and the haze H is 3%. Correspondingly, ξ is 0.08.

[0071] Example 7

[0072] The embodiment scheme is basically the same as that of Embodiment 1, except that the substrate is replaced by a mixed substrate of PET and PMMA, the mass content of PET in the mixed substrate is 50%, the mass content of PMMA in the mixed substrate is 50%, and the haze H is 2%. Correspondingly, ξ is 0.13.

[0073] Embodiment 8

[0074] The embodiment scheme is basically the same as that of Embodiment 1, except that the substrate is replaced by a mixed substrate of PET and PMMA, the mass content of PET in the mixed substrate is 95%, the mass content of PMMA in the mixed substrate is 5%, and the haze H is 1%. Correspondingly, ξ is 0.26.

[0075] Comparative Example 1

[0076] The comparative example scheme is basically the same as that of Embodiment 1, except that no particles are added, the haze H is 0.2%, and correspondingly, ξ is 0.

[0077] Comparative Example 2

[0078] The comparative example scheme is basically the same as that of Embodiment 1, except that the length diameter of the particles is 20 microns, the short diameter is 20 microns, the number of particles per unit volume R is 0.1, the haze H is 4%, and correspondingly, ξ is 2.5.

[0079] Comparative Example 3

[0080] The comparative example scheme is basically the same as that of Embodiment 1, except that the length diameter of the particles is 43 microns, the short diameter is 43 microns, the number of particles per unit volume R is 1, the haze H is 18%, and correspondingly, ξ is 5.6.

[0081] The optical films of the above embodiments and comparative examples are subjected to performance tests, and the test results are shown in Table 1 below.

[0082] Table 1

[0083]

[0084] According to the comparison of Embodiments 1-8 and Comparative Examples 1-3, the optical films prepared in Embodiments 1-8 have better effects of improving rainbow stripes than the optical films prepared in Comparative Examples 1-3, and the possible reason is that the in-plane retardation value and the thickness direction retardation value of the optical films prepared in Embodiments 1-8 are smaller, which reduces the difference between the in-plane retardation value and the thickness direction value, thereby being conducive to improving rainbow stripes.

[0085] According to the comparison between the above-mentioned embodiment 1 and embodiment 6, the optical film prepared in embodiment 1 has better comprehensive performance, such as the improvement ability of the difference between the tensile property, the in-plane retardation value and the thickness direction retardation value, compared with the optical film prepared in embodiment 6, and the possible reason is that the tensile property and the anisotropy of the refractive index of the PET substrate are better than those of the PMMA substrate.

[0086] According to the comparison between the above-mentioned embodiments 1-2 and embodiment 4, the optical film prepared in embodiments 1-2 has better comprehensive performance, such as the improvement ability of the difference between the tensile property, the in-plane retardation value and the thickness direction retardation value, compared with the optical film prepared in embodiment 4, and the cubic particles have better performance than the spherical particles in the above-mentioned comprehensive performance.

[0087] According to the comparison between the above-mentioned embodiment 1 and comparative examples 2-3, the optical film prepared in embodiment 1 has obvious effect of improving rainbow stripes compared with the optical films prepared in comparative examples 2-3, and the possible reason is that the particles with relatively small particle size doped in the optical film are more conducive to reducing the difference between the in-plane retardation value and the thickness direction retardation value.

[0088] According to the comparison between the above-mentioned embodiments 1-2 and other embodiments, the optical film prepared in embodiments 1-2 has better overall performance, such as the tensile property, the improvement of rainbow stripes and the transmittance, and the possible reason is that by controlling the crystallinity of the optical film to be 17% to 21% and the melt index of the optical film to be 0.45 to 0.48, the mechanical property and the optical transmittance of the optical film can be improved while the difference between the in-plane retardation value and the thickness direction retardation value is significantly reduced.

[0089] In the above-mentioned embodiments, the description of each embodiment has its own focus, and the part not described in detail in a certain embodiment can be referred to the related description of other embodiments.

[0090] The above has carried on the detailed introduction to the optical film, the polarizer and the display device provided by the embodiments of the application, the principle and the implementation mode of the application are described by applying specific examples in this paper, and the above embodiment description is only used to help understanding the technical scheme of the application and its core idea; the person skilled in the art should understand that: it can still modify the technical scheme recorded in the above-mentioned embodiments, or make equivalent replacement to part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical scheme deviate from the scope of the technical scheme of the embodiments of the application.

Claims

1. An optical film, wherein, The optical film comprises: a substrate; and particles dispersed in the substrate; wherein 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 100, and the ratio of the number of the particles dispersed in every cubic micron of the optical film to the haze of the optical film is greater than 0 and less than or equal to 100. The haze is greater than or equal to 0.01% and less than or equal to 20%.

2. The optical film of claim 1, wherein, The in-plane retardation value of the optical film is less than or equal to 3,000 nm, and the thickness-direction retardation value of the optical film is less than or equal to 6,000 nm.

3. The optical film of claim 2, wherein, 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.

4. The optical film of claim 2, wherein, 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 40, the haze is greater than or equal to 1% and less than or equal to 2%, and the ratio of the number of the particles dispersed in every cubic micron of the optical film to the haze is greater than or equal to 0.1 and less than or equal to 0.

4.

5. The optical film of claim 2, wherein, The optical film has a breaking strength of 10 N / mm 2 to 500 N / mm 2 and an elongation at break of 10% to 200%.

6. The optical film of claim 2, wherein, The in-plane retardation value of the optical film is less than or equal to 190 nm, and the thickness-direction retardation value of the optical film is less than or equal to 500 nm.

7. The optical film of claim 6, wherein, 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.

8. The optical film of claim 6, wherein, 9. 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%. The substrate includes, but is not limited to, tri-acetyl cellulose, polyethylene terephthalate, polycarbonate, polymethyl methacrylate, polyalkene, polyethylene naphthalate; and / or 10. The optical film of claim 1, wherein, 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, silicone, polybutyl acrylate-styrene, poly-4-hydroxybenzyl methacrylate, silicon dioxide, silicon carbide, silicon nitride, zinc oxide, magnesium oxide, aluminum oxide, calcium sulfate, calcium carbonate, potassium titanate, aluminum borate.

11. The optical film according to claim 1, wherein the mass content of the particles in the optical film is less than 30%; and / or the thickness of the optical film is 5 microns to 500 microns; and / or the particle size of the particles is greater than or equal to 0.1 microns and less than or equal to 300 microns; and / or the glass transition temperature of the substrate is 20°C to 600°C. The material of the particles includes at least one of a modified or unmodified inorganic substance, a modified or unmodified organic substance.

12. The optical film of claim 1, wherein, The optical film comprises a polarizing layer and an optical film, the optical film being the optical film according to any one of claims 1 to 12, the slow-axis direction of the optical film and the slow-axis direction of the optical functional layer being perpendicular to the absorption axis of the polarizing layer.

13. A polarizing sheet, wherein, ​ 14. The polarizing sheet according to claim 13, wherein The polarizing sheet further includes an optical functional layer on a side of the optical film away from the polarizing layer, the optical functional layer including at least one of an anti-glare layer, a hard coat layer, an anti-reflection layer, a low-reflection layer, an anti-fingerprint layer, and an anti-static layer.

15. A display device, wherein, A display panel including the polarizing sheet according to claim 13 or 14.

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