Optical films, polarizers, and display devices

Abstract

Embodiments of the present application disclose an optical film, a polarizer, and a display device, wherein the optical film comprises a substrate and particles dispersed in the substrate, the number of particles per 10,000 cubic microns of the optical film is 100 or less, and the ratio of the number of particles dispersed per cubic micron to the haze of the optical film is greater than 0 and 100 or less. With the above design, the difference between the in-plane phase difference value and the thickness direction phase difference value of the optical film is reduced, improving the rainbow pattern phenomenon and providing excellent mechanical properties. In addition, when the optical film is used in a display device, the chromaticity viewing angle is also improved and high transmittance can be maintained.

Description

[Technical Field]

[0001] This application relates to the field of display technology, and more particularly to optical films, polarizers, and display devices. [Background technology]

[0002] Polarizers are widely used in the display field, and generally, an optical film is used on the polarizing layer of a polarizer to protect it. However, optical films usually have birefringence, and their refractive index is anisotropic. Therefore, light passing through the optical film is decomposed into ordinary light and extraordinary light with a certain phase difference value. When the phase difference value of the two lights exceeds a certain range, light interference occurs, creating a rainbow pattern, which degrades the display quality when a polarizer is used in a display device.

[0003] Furthermore, while diffusing particles are added to the optical film to improve the chromaticity and viewing angle of the display, research by the inventors has revealed that adding diffusing particles within a certain range negatively affects the in-plane phase difference value of the optical film. As a result, the difference between the in-plane phase difference value and the thickness-direction phase difference value becomes too large, worsening the rainbow pattern. [Overview of the project]

[0004] The embodiments of this application provide an optical film, a polarizer, and a display device that solve the technical problem that adding a certain amount of diffusing particles to an existing optical film may worsen the rainbow pattern.

[0005] To solve the above problems, the technical solutions provided by this application are as follows: Embodiments of the present application provide an optical film comprising a substrate and particles dispersed in the substrate, wherein the number of particles dispersed per 10,000 cubic microns of the optical film is greater than 0 and 100 or less, and the ratio of the number of particles dispersed per cubic micron to the haze is greater than 0 and 100 or less.

[0006] In some embodiments of the present application, the haze of the optical film is 0.01% or more and 20% or less.

[0007] In some embodiments of the present application, the in-plane phase difference of the optical film is 3000 nanometers or less, and the phase difference of the optical film in the thickness direction is 6000 nanometers or less.

[0008] 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 0.15 or less.

[0009] In some embodiments of this application, the breaking strength of the optical film is 10 N / mm². 2 ~500N / mm 2 The elongation at break is 10% to 200%.

[0010] In some embodiments of the present application, the number of particles dispersed per cubic micron is 0.002 or more and 0.004 or less, the haze is 1% or more and 2% or less, and the ratio of the number of particles dispersed per cubic micron to the haze is 0.1 or more and 0.4 or less.

[0011] In some embodiments of the present application, the in-plane phase difference of the optical film is 190 nanometers or less, and the thickness-direction phase difference of the optical film is 500 nanometers or less.

[0012] 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 0.003 or more and 0.007 or less.

[0013] In some embodiments of the present application, the melt index of the optical film is 0.35 or more and 0.55 or less, and / or the degree of crystallinity of the optical film is 15% or more and 35% or less.

[0014] 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.

[0015] 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 frustum of a pyramid, a sheet shape, a single-needle shape, a three-needle shape, a four-needle shape, a petal shape, a dish shape, and a spiral shape.

[0016] 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.

[0017] In some embodiments of the present application, the particles account for less than 30% of the mass content of the optical film.

[0018] In some embodiments of the present application, the thickness of the optical film is 5 µm to 500 µm.

[0019] In some embodiments of the present application, the particle diameter of the particles is not less than 0.1 µm and not more than 300 µm.

[0020] In some embodiments of the present application, the glass transition temperature of the substrate is 20°C to 600°C.

[0021] Based on the optical film of the above embodiments, an embodiment of the present application further provides a polarizer including a polarizing layer and the optical film according to any one 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.

[0022] In some embodiments of the present application, the polarizer further includes the optically functional layer located on a side of the optical film opposite to the polarizing layer, and the optically functional layer includes 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 antistatic layer.

[0023] Based on the polarizer of the above embodiments, an embodiment of the present application further provides a display device including the polarizer according to any one of the above embodiments and a display panel.

[0024] The beneficial effects of the present application are as follows. In the present application, the optical film is designed such that the number of particles per 10000 cubic microns is 100 or less, and the ratio of the number of dispersed particles per cubic micron to haze is greater than 0 and 100 or less. The above design reduces the difference between the in-plane retardation value and the thickness direction retardation value of the optical film, improves the rainbow pattern phenomenon, provides excellent mechanical properties, and also improves the chromaticity viewing angle when the optical film is applied to a display device, and maintains high transmittance. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments or the prior art, the following briefly introduces the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art based on these drawings without creative efforts.

[0026] [Figure 1] It is a schematic structural diagram of an optical film provided in an embodiment of the present application. [Figure 2] It is a schematic structural diagram of a polarizer provided in an embodiment of the present application. [Figure 3] It is a schematic structural diagram of a display device provided in an embodiment of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0027] The technical solutions in the embodiments of this application are described below clearly and completely with reference to the accompanying drawings of the embodiments. Obviously, the embodiments described are only a part of the embodiments of this application, not all of them. All other embodiments that can be obtained by those skilled in the art without creative effort based on the embodiments of this application are included within the scope of protection of this application.

[0028] Furthermore, please understand that the orientations and positional relationships indicated by terms such as "thickness," "top," and "bottom" in this description are based on the orientations and positional relationships shown in the drawings. These are solely for the convenience of this description and the simplified description, and do not indicate or imply that the devices or elements mentioned must have a specific orientation, or must be constructed and operate in a specific orientation, and therefore should not be understood as limiting this application.

[0029] The following disclosure provides many different embodiments or examples for implementing various structures of the Application. For the sake of brevity of the disclosure, the components and arrangements of specific examples are described below. Of course, these are merely examples and do not limit the Application. Furthermore, the Application may repeat reference numbers and / or reference letters in different examples, but such repetitions are for the purpose of simplification and clarification and do not, in themselves, indicate relationships between the various embodiments and / or configurations discussed. Furthermore, the Application provides examples of various specific processes and materials, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0030] This invention proposes this embodiment to overcome the shortcomings of existing optical films, in which particles are added to the optical film to improve the chromaticity and viewing angle of the display. When the amount of diffuse particles added exceeds a certain range, it adversely affects the in-plane phase difference value of the optical film, resulting in an excessively large difference between the in-plane phase difference value and the thickness-direction phase difference value, which worsens the rainbow pattern.

[0031] As shown in Figure 1, an embodiment of the present invention provides an optical film 10 comprising a substrate 11 and particles 12 dispersed in the substrate 11. 10,000 μm in the optical film 10 3 The number of particles per unit volume (μm) is greater than 0 and less than or equal to 100, i.e., the number of particles per unit volume (μm). 3 The number of particles R per unit volume is greater than 0 and less than or equal to 0.01. The ratio of the number of particles R per unit volume to the haze H of the optical film 10 is defined as ξ, and ξ is greater than 0 and less than or equal to 100.

[0032] When particles are added to the optical film 10, the chromaticity viewing angle when the optical film 10 is used in a display device is improved. However, the addition of particles causes an increase in haze H, which affects the transmittance. At the same time, the inventors have discovered that when the number of particles exceeds a certain range, the iridescent pattern of the optical film 10 deteriorates. The optical film 10 provided in the embodiment of this application is designed with the number of particles R per unit volume and the ξ(R / H) value within the above range, thereby reducing the difference between the in-plane phase difference value and the thickness direction phase difference value of the optical film 10, improving the iridescent pattern phenomenon, and not only possessing excellent mechanical properties, but also improving the chromaticity viewing angle when the optical film 10 is used in a display device and maintaining high transmittance.

[0033] In the embodiments of this application, the haze H of the optical film 10 is between 0.01% and 20%. Within this range, the rainbow pattern phenomenon can be effectively improved, mechanical properties can be enhanced, and transmittance can be ensured. Specifically, in the embodiments of this application, the in-plane phase difference value of the optical film 10 is 3000 nanometers or less, and the thickness-direction phase difference value of the optical film 10 is 6000 nanometers or less. The in-plane phase difference value refers to the phase difference value in the plane on which the optical film 10 is placed, and the thickness-direction phase difference value refers to the phase difference value in the direction perpendicular to the plane on which the optical film 10 is placed. In this application, by designing the number of particles R per unit volume, haze H, and ξ value to be within the above range, the in-plane phase difference value of the optical film 10 can be reduced, so that the difference between the in-plane phase difference value and the thickness-direction phase difference value becomes smaller, thereby improving the rainbow pattern phenomenon.

[0034] 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 formulas. TIFF2026531069000002.tif60140

[0035] 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 a larger refractive index) on the plane where the optical film is disposed, n y is the refractive index in the fast axis direction (the direction with a smaller refractive index) on the plane where the optical film is disposed, n z is the refractive index in the direction perpendicular to the plane where the optical film is disposed, and the slow axis direction and the fast axis direction are orthogonal to each other.

[0036] In the embodiment of the present application, through the matching design of the number of particles per unit volume R, haze H and ξ value, the slow axis refractive index n of the optical film 10 of the present application x and the fast axis refractive index n y can have a difference of 0.15 or less, thereby reducing the refractive index difference in different directions of the optical film 10 and improving the rainbow pattern phenomenon.

[0037] The optical film 10 can be manufactured by processes such as slicing the base material 11, mechanically mixing the sliced base material and particles, melt co-extrusion, cast film formation, and stretching. Through the matching design of the number of particles per unit volume R, haze H and ξ value, the breaking strength of the optical film 10 of the present application can reach 10N / mm 2 ~500N / mm 2 , which has excellent resistance to tensile damage, the elongation at break can reach the range of 10% to 200%, which has excellent plastic deformation capability, furthermore, the optical film 10 provided in the present application has excellent tensile properties.

[0038] In some embodiments, the intrinsic viscosity of the substrate 11 slices after mechanical mixing with particles can be controlled between 0.35 and 0.95. Correspondingly, the optical film 10 can be characterized by its 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 embodiments of this application, the melt index can be tested using a melt index meter such as XNR400, with the standard of practice being ASTM D1238.

[0039] There is an inverse relationship between the melt index of the film and the intrinsic viscosity of the slice. Intrinsic viscosity affects the tensile and mechanical properties of the formed film; the higher the intrinsic viscosity of the slice, the better the tensile and mechanical properties of the formed film. That is, the smaller the melt index of the optical film 10, the better the mechanical properties of the optical film 10. Selectively, the melt index of the optical film 10 may be between 0.38 and 0.55, 0.38 and 0.48, 0.45 and 0.48, or any two endpoint values ​​within this range. Within this range, it is possible to reduce the difference in phase difference values ​​in different directions of the optical film 10 while maintaining the excellent mechanical properties of the optical film 10, thereby improving the rainbow pattern phenomenon.

[0040] 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 light transmittance, haze H, mechanical properties, and phase difference values ​​of the film. By controlling the crystallinity of the optical film 10 within this range, light loss can be reduced, the difference in phase difference values ​​in different directions of the optical film 10 can be reduced, and the rainbow pattern phenomenon can be improved. In embodiments of the present application, the crystallinity can be measured by the DSC (Differential Scanning Calorimetry) method, specifically by a DSC3500Sirius differential scanning calorimetry meter.

[0041] Selectively, the degree of crystallinity of the optical film 10 may be 15% to 25%, 19% to 25%, 19% to 22%, 17% to 21%, or a value between any two of the above endpoint values. By controlling the degree of crystallinity within this range, not only can high transmittance be ensured, but the difference in phase difference values ​​in different directions of the optical film 10 can be reduced over a long range, thereby improving the rainbow pattern phenomenon.

[0042] In some examples, the unit volume (μm) 3 The number of particles R per ) may be 0.008 or less, and may be 0.006 or less, and may be 0.004 or less.

[0043] In some embodiments, the haze H may be 15% or less, 8% or less, 6% or less, or even 2% or less.

[0044] Selectively, in some examples, the number of particles per 10,000 cubic microns is 20 to 40, i.e., per unit volume (μm). 3 The number of particles R per ) may be 0.002 or more and 0.004 or less, the haze H may be 1% or more and 2% or less, and ξ may be 0.1 or more and 0.4 or less. Within the above design range, the in-plane phase difference value of the optical film 10 will be 190 nanometers or less, and the thickness direction phase difference value will be 500 nanometers or less, further reducing the difference between the in-plane phase difference value and the thickness direction phase difference value, and further effectively improving the rainbow pattern phenomenon. Within the above design range, the slow axis refractive index n of the optical film 10 x and the leading axis refractive index n y The difference can be controlled to be between 0.003 and 0.007, effectively reducing the anisotropy of the refractive index of the optical film 10, reducing light interference, and further improving the rainbow pattern phenomenon.

[0045] In some examples, the glass transition temperature of the substrate 11 of the optical film 10 is 20°C to 600°C.

[0046] In some embodiments, the substrate 11 of the optical film 10 comprises at least one of cellulose triacetate (TAC), polyethylene terephthalate (PET), polycarbonate (PC), polymethyl methacrylate (PMMA), polycycloolefin (COP / COC), and polyethylene naphthalate (PEN). Selectively, 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.

[0047] In some embodiments, the thickness of the optical film 10 may be between 5 microns and 500 microns, specifically between 5 microns and 450 microns, 10 microns and 400 microns, 20 microns and 350 microns, 30 microns and 300 microns, 40 microns and 250 microns, 45 microns and 200 microns, 50 microns and 150 microns, 60 microns and 120 microns, 65 microns and 100 microns, or a value between any two of the above endpoint values.

[0048] 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 a value between any two of the above endpoints. By controlling the particle mass content within this range, it is possible to balance the crystallinity, melt index, haze H, and transmittance of the film material.

[0049] In some embodiments, the material of particle 12 may include at least one of a modified or unmodified inorganic substance and a modified or unmodified organic substance. Examples of inorganic substances include 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 33The following are examples of organic materials, but are not limited to them: at least one of the following: polymethyl methacrylate (PMMA), polystyrene (PS), silicone, polybutyl acrylate-styrene, and poly-4-hydroxybenzyl ester. The particulate materials listed above can be surface modified.

[0050] In some embodiments, the shape of the particle 12 may include at least one of spherical or non-spherical shapes. Specifically, the particle shape includes, but is not limited to, at least one of sphere, ellipsoid, cube, rectangular prism, cone, cylinder, truncated pyramidal shape, sheet-like, single-needle (rod-like), three-needle, four-needle, petal-like, dish-like, and spiral shapes.

[0051] In some embodiments, the particle size of particle 12 is between 0.1 microns and 300 microns. When the particle shape is non-spherical, the particle size is between 0.1 microns and 300 microns, meaning that both the minor and major axes of the particle are in the range of 0.1 microns and 300 microns. Specifically, the particle size (major or minor axis) may be between 0.1 and 280 microns, 1 and 250 microns, 3 and 230 microns, 5 and 200 microns, 7 and 180 microns, 10 and 150 microns, 13 and 130 microns, 15 and 100 microns, 20 and 80 microns, 23 and 70 microns, 26 and 50 microns, 30 and 40 microns, or a value between any two of the above endpoint values.

[0052] As shown in Figure 2, based on the above embodiments, the present embodiment further provides a polarizer 100 comprising an optical film 10 and a polarizing layer 20 as in any of the above embodiments. The absorption axis of the polarizing layer 20 is perpendicular to the slow phase axis direction of the optical film 10.

[0053] In some embodiments, the polarizing layer 20 may be a PVA (polyvinyl alcohol) film layer.

[0054] In some embodiments, the polarizer 100 further includes an optical functional layer 30 located on the opposite side of the polarizing layer 20 of the optical film 10, and the optical functional layer 30 may be a single layer or a composite multilayer structure. The optical functional layer 30 includes, but is not limited to, at least one of an anti-glare layer, a hard coat layer, an anti-reflective layer, a low-reflection layer, an anti-fingerprint layer, and an anti-static layer. For example, the optical functional layer may be a laminated structure of a hard coat layer and an anti-reflective layer.

[0055] The hard coat layer has high hardness, is waterproof and oil-resistant, effectively prevents scratches on the surface of the underlying film layer, and is easy to clean. Selectively, the glass transition temperature of the hard coat layer is high, for example, 70°C to 120°C. The material of the hard coat layer may include at least one of polyurethane resin, acrylic resin, epoxy resin, vinyl resin, and silicone resin.

[0056] The anti-reflective layer is used to prevent reflections and also protects against scratches. The anti-reflective layer may be a dielectric film formed on the surface of the hard coat layer.

[0057] In some embodiments, the polarizer 100 further includes sequentially laminated release films 40, pressure-sensitive adhesive layers 50, and optical compensation layers 60. A polarizing layer 20, an optical film 10, and an optical functional layer 30 are sequentially laminated on the optical compensation layer 60.

[0058] The function of the release film 40 is to protect the pressure-sensitive adhesive layer 50 from damage and to avoid the formation of bonding bubbles before the polarizer 100 is bonded to the display panel. The release film 40 may be a polyester film such as polyethylene terephthalate film, a polyolefin film such as polyethylene film or polypropylene film, or a polytetrafluoroethylene film. To allow the release film 40 to be easily peeled off, a release-treated film such as a siloxane resin, melamine resin, or urea resin may be used.

[0059] The pressure-sensitive adhesive layer 50 is used to bond the release film 40 to the optical compensation layer 60 provided on the release film 40. The material of the pressure-sensitive adhesive layer 50 may be, for example, acrylic resin.

[0060] The optical compensation layer 60 may be a compensation layer or a phase difference film, etc., in which a liquid crystalline compound is applied to the surface of the substrate and its orientation is fixed.

[0061] 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 direction of incident light.

[0062] The protective layer 70 is used to protect the underlying film layer. The protective layer 70 may be a transparent resin film formed from a thermoplastic resin such as a polyolefin resin such as a chain polyolefin resin (polypropylene resin, etc.) or a cyclic polyolefin resin (norbornene resin, etc.), a cellulose ester resin such as cellulose triacetate or cellulose diacetate, a polyester resin such as polyethylene terephthalate, polyethylene naphthalate or polybutylene terephthalate, a polycarbonate resin, a (meth)acrylic resin, or a mixture or copolymer thereof.

[0063] As shown in Figure 3, an embodiment of the present invention 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 opposite side from the light-emitting side of the display panel 200.

[0064] In some embodiments, the display panel 200 may be a liquid crystal display panel, and the structure of the liquid crystal display panel can be described again here, as it can be found in existing technologies.

[0065] In the embodiments of the present application, at least one of the upper polarizer 100A and the lower polarizer 100B may adopt the structure of the polarizer 100 in the above embodiment. When the polarizer 100 of the above embodiment is used as the upper polarizer 100A, the optical film 10 is positioned on the opposite side of the display panel of the polarizing layer 20, and when the polarizer 100 of the above embodiment is used as the lower polarizer 100B, the optical film 10 is positioned on the display panel side of the polarizing layer 20.

[0066] This invention provides a polarizer 100 equipped with the above-mentioned optical film 10 to a display device 1000, thereby improving the rainbow pattern phenomenon, providing excellent mechanical properties, improving the chromaticity viewing angle of the display device 1000, and maintaining high transmittance.

[0067] In some embodiments, the display device 1000 further includes a backlight module 300. The backlight module 300 may include a backlight, which may be a direct-lit backlight or an edge-lit backlight.

[0068] The backlight module 300 may be any type of backlight module, for example, a quantum dot type backlight module that uses quantum dots and is suitable for a wide color gamut. Specifically, the backlight may include an array of light-emitting diodes and a color conversion layer. These 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 backlights of different colors and 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 a yellow phosphor, the second color conversion unit may include a green phosphor, the third color conversion unit may include a red phosphor and a green phosphor, and the fourth color conversion unit may include a red fluorescent quantum dot material, a green fluorescent quantum dot material, and a blue fluorescent quantum dot material.

[0069] In some embodiments, the display device 1000 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, with an in-plane phase difference value of 300 nanometers to 500 nanometers.

[0070] This application verifies the performance of the optical film provided herein through the following specific embodiments.

[0071] Example 1 First, a PET substrate is sliced, and the sliced ​​PET substrate and calcium carbonate particles are mechanically mixed. The particles are cubic in shape, with a major axis of 2 microns and a minor axis of 2 microns, and a mass content of 0.10%. Then, the sheet is cast using a melt extrusion process, and cast into a film using a film forming system. Next, the film-formed substrate is stretched (longitudinal stretching ratio 3x, transverse stretching ratio 2x) to obtain an optical film with a thickness of 40 microns. Unit volume of optical film (μm 3 The number of particles per unit area R is 0.0026, the haze H is 3%, and ξ(R / H) is 0.087.

[0072] Example 2 The scheme of this embodiment is basically the same as that of Embodiment 1, the only difference being that the particle mass content is 0.50%, the number of particles per unit volume R is 0.013, and the haze H is 4%. Correspondingly, ξ is 0.325.

[0073] Example 3 The scheme of this embodiment is basically the same as that of Embodiment 1, the only difference being that the particle mass content is 0.88%, the number of particles per unit volume R is 0.023, and the haze H is 6%. Correspondingly, ξ is 0.383.

[0074] Example 4 The scheme of this embodiment is basically the same as that of Embodiment 1, the only difference being that the particle shape is spherical, with a diameter of 2 microns and a haze H of 4%. Correspondingly, ξ is 0.065.

[0075] Example 5 The scheme of this embodiment is basically the same as that of Embodiment 1, the only difference being that the particle shape is rod-shaped, with a major axis of 20 microns, a minor axis of 2 microns, and a haze H of 5%. Correspondingly, ξ is 0.052.

[0076] Example 6 The scheme of this embodiment is basically the same as that of Embodiment 1, the only difference being that the substrate is replaced with a mixed substrate of PET and PMMA, where PET accounts for 5% of the mass content of the mixed substrate, PMMA accounts for 95% of the mass content of the mixed substrate, and haze H is 3%. Correspondingly, ξ is 0.08.

[0077] Example 7 The scheme of this embodiment is basically the same as that of Embodiment 1, the only difference being that the substrate is replaced with a mixed substrate of PET and PMMA, with PET accounting for 50% of the mass content of the mixed substrate, PMMA accounting for 50% of the mass content of the mixed substrate, and the haze H being 2%. Correspondingly, ξ is 0.13.

[0078] Example 8 The scheme of this embodiment is basically the same as that of Embodiment 1, the only difference being that the substrate is replaced with a mixed substrate of PET and PMMA, where PET accounts for 95% of the mass content of the mixed substrate, PMMA accounts for 5% of the mass content of the mixed substrate, and haze H is 1%. Correspondingly, ξ is 0.26.

[0079] Comparative Example 1 The scheme of this comparative example is basically the same as that of Example 1, the only differences being that no particles are added, the haze H is 0.2%, and correspondingly ξ is 0.

[0080] Comparative Example 2 The scheme of this comparative example is basically the same as that of Example 1, the only difference being that the major axis of the particles is 20 microns, the minor axis is 20 microns, the number of particles per unit volume R is 0.1, and the haze H is 4%, correspondingly ξ is 2.5.

[0081] Comparative Example 3 The scheme of this comparative example is basically the same as that of Example 1, the only difference being that the major axis of the particles is 43 microns, the minor axis is 43 microns, the number of particles per unit volume R is 1, and the haze H is 18%, correspondingly ξ is 5.6.

[0082] The results of performance tests conducted on the optical films of the above examples and comparative examples are shown in Table 1 below. [Table 1]

[0083] A comparison of Examples 1-8 and Comparative Example 1-3 above shows that the optical film produced in Example 1-8 exhibits a superior improvement in the rainbow pattern phenomenon compared to the optical film produced in Comparative Example 1-3. This is likely because the in-plane phase difference and thickness-direction phase difference of the optical film produced in Example 1-8 are both small, resulting in a smaller difference between the in-plane phase difference and the thickness-direction phase difference, thus improving the rainbow pattern phenomenon.

[0084] A comparison of Example 1 and Example 6 above reveals that the optical film produced in Example 1 has superior overall properties compared to the optical film produced in Example 6, including tensile properties and the ability to improve the difference between the in-plane phase difference value and the thickness direction phase difference value. This is thought to be because the tensile properties and refractive index anisotropy of the PET substrate are superior to those of the PMMA substrate.

[0085] A comparison of Examples 1-2 and 4 above shows that the optical film produced in Example 1-2 is superior to the optical film produced in Example 4 in terms of overall characteristics, such as tensile properties and the ability to improve the difference between the in-plane phase difference value and the thickness direction phase difference value. From the viewpoint of the above overall characteristics, cubic particles exhibit superior performance compared to spherical particles.

[0086] A comparison of Example 1 and Comparative Examples 2-3 above shows that the optical film produced in Example 1 has a clear effect in improving the rainbow pattern phenomenon compared to the optical films produced in Comparative Examples 2-3. This is thought to be because adding relatively small particles to the optical film is more advantageous in reducing the difference between the in-plane phase difference value and the thickness-direction phase difference value.

[0087] A comparison of Examples 1-2 described above with other examples shows that the optical film produced in Example 1-2 exhibits superior overall properties such as tensile strength, improved iridescence, and transmittance. This is thought to be due to the significant reduction in the difference between the in-plane phase difference and the thickness-direction phase difference, while improving the mechanical properties and light transmittance of the optical film, achieved by controlling the crystallinity of the optical film to 17%-21% and the melt index of the optical film to 0.45-0.48.

[0088] In the embodiments described above, each embodiment is explained with its own emphasis; however, for aspects not explained in detail in one embodiment, please refer to the relevant descriptions in other embodiments.

[0089] The above is a detailed introduction to the optical films, polarizers, and display devices provided in the embodiments of the present application. While this specification uses specific examples to illustrate the principles and embodiments of the present application, the above description of the embodiments is used solely for the purpose of understanding the technical solutions and inventive ideas of the present application. Those skilled in the art should understand that they may modify the technical solutions described in the above embodiments or make equivalent substitutions for certain technical features, and that such modifications or substitutions will not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of each embodiment of the present application.

Claims

1. It is an optical film, Substrate and Includes particles dispersed in a substrate, Herein, the optical film is characterized in that the number of particles dispersed per 10,000 cubic microns of the optical film is greater than 0 and 100 or less, and the ratio of the number of particles dispersed per cubic micron to the haze of the optical film is greater than 0 and 100 or less.

2. The optical film according to claim 1, characterized in that the haze is 0.01% or more and 20% or less.

3. The optical film according to claim 2, characterized in that the in-plane phase difference value of the optical film is 3000 nanometers or less, and the phase difference value in the thickness direction of the optical film is 6000 nanometers or less.

4. The optical film according to claim 2, characterized in that the difference between the slow-axis refractive index of the optical film and the fast-axis refractive index of the optical film is 0.15 or less.

5. The breaking strength of the optical film is 10 N / mm². ２ ~500 N / mm ２ The optical film according to claim 2, characterized in that the elongation at break is 10% to 200%.

6. The optical film according to claim 2, characterized in that the number of particles dispersed per 10,000 cubic microns is 20 or more and 40 or less, the haze is 1% or more and 2% or less, and the ratio of the number of particles dispersed per cubic micron to the haze is 0.1 or more and 0.4 or less.

7. The optical film according to claim 6, characterized in that the in-plane phase difference value of the optical film is 190 nanometers or less, and the thickness-direction phase difference value of the optical film is 500 nanometers or less.

8. The optical film according to claim 6, characterized in that the difference between the slow-axis refractive index of the optical film and the fast-axis refractive index of the optical film is 0.003 or more and 0.007 or less.

9. The melt index of the optical film is between 0.35 and 0.

55. The optical film according to claim 1, characterized in that the degree of crystallinity of the optical film is 15% or more and 35% or less.

10. The base material includes cellulose triacetate, polyethylene terephthalate, polycarbonate, polymethyl methacrylate, polycycloolefin, polyethylene naphthalate, and / or The particle shapes include at least one of spheres, ellipsoids, cubes, cuboids, cones, cylinders, truncated pyramidal structures, sheet-like, uniacinate, triacinate, quadracinate, petal-like, saucer-like, and spiral shapes, and / or The optical film according to claim 1, characterized in that the particle material includes at least one of the following: polymethyl methacrylate, polystyrene, silicone, polybutylacrylate-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.

11. The particles constitute less than 30% of the mass content of the optical film, and / or The thickness of the optical film is 5 microns to 500 microns, and / or The particle size is 0.1 microns or more and 300 microns or less, and / or The optical film according to claim 1, characterized in that the glass transition temperature of the substrate is 20°C to 600°C.

12. A polarizer comprising a polarizing layer and an optical film, wherein the optical film is the optical film described in any one of claims 1 to 11, and 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.

13. The polarizer according to claim 12, further comprising an optical functional layer located on the opposite side of the polarization layer of the optical film, wherein the optical functional layer comprises at least one of an anti-glare layer, a hard coat layer, an anti-reflective layer, a low-reflection layer, an anti-fingerprint layer, and an anti-static layer.

14. A display device comprising the polarizer and display panel described in claim 12.

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