Optical film, polarizer and display device

Abstract

The present application relates to an optical film, a polarizer, and a display device. The optical film includes a substrate layer and a depolarization layer located on one side of the substrate layer. The depolarization layer includes at least one main layer and birefringent particles dispersed in the at least one main layer. The angle between the slow axis direction of the birefringent particles and the winding direction of the substrate layer is greater than or equal to 35° and less than or equal to 55°. When linearly polarized light is incident on the optical film, the linearly polarized light is converted into circularly polarized light and / or elliptically polarized light by the depolarization layer. The present application can achieve a depolarization effect through a method with a simpler process, lower cost, and higher yield, thereby providing eye protection.

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] Natural light is evenly distributed in all directions when it enters the human eye, creating the softest and most comfortable sensation. Humans have long lived and evolved in natural light environments, and therefore, of all light sources, natural light is considered the most eye-friendly. However, the light emitted by LCD displays is generally linearly polarized, which limits the stimulation to the human eye to a single direction and location. Prolonged exposure to uneven light can easily lead to visual fatigue.

[0003] There are two solutions to improve the problem of visual fatigue caused by linear polarization of liquid crystal displays. One method is to attach a quarter-wave plate to the upper polarizer of the liquid crystal display, and the quarter-wave plate forms a 45° angle with the light absorption axis or transmission axis of the polarizer, so that the linear polarization emitted from the upper polarizer of the liquid crystal display is converted into circular polarization and / or elliptically polarized light through the quarter-wave plate. Since circular polarization has an optical property similar to natural light that is uniformly distributed in all directions, and elliptically polarized light has an optical property that is uniformly distributed in some directions, visual fatigue of the human eye can be improved. However, due to the high price of the quarter-wave plate, the cost of liquid crystal displays has been greatly increased. Another method is to laminate a transparent substrate layer with high in-plane retardation (in-plane retardation ≥ 8000nm) on the upper polarizer of the liquid crystal display. The transparent substrate layer with high in-plane retardation forms a 45° angle with the light absorption axis or transmission axis of the polarizer, so that the linear polarized light emitted from the upper polarizer of the liquid crystal display passes through the transparent substrate layer with high in-plane retardation. After that, multiple wavelengths of colored light in the visible light wavelength range are converted into circularly polarized light and / or elliptically polarized light. This method can also make the output light of the liquid crystal display achieve an effect similar to natural light that is uniformly distributed in all directions, thereby improving visual fatigue of the human eye. However, this method requires cutting the transparent substrate layer with high in-plane retardation at 45° and then laminating it with the polarizer, which results in a complicated process and low yield, and is not easy to mass produce.

[0004] Therefore, it is necessary to provide a new film layer structure and method to solve the above technical problems. Summary of the Invention

[0005] The embodiments of the present application provide an optical film, a polarizer, and a display device, which can achieve a depolarization effect through a method with a simpler process, lower cost, and higher yield, thereby achieving an eye protection effect.

[0006] In order to achieve the above-mentioned object, according to a first aspect of the present application, an optical film is provided, comprising:

[0007] substrate layer;

[0008] a depolarization functional layer located on one side of the substrate layer; the depolarization functional layer comprises at least one main layer and birefringent particles dispersed in the at least one main layer;

[0009] The angle between the slow axis direction of the birefringent particles and the winding direction of the substrate layer is greater than or equal to 35° and less than or equal to 55°; when linear polarization is incident on the optical film, the linear polarization is converted into circular polarization and / or elliptically polarized light by the depolarization functional layer.

[0010] In some embodiments, the refractive index of visible light in the slow axis direction of the birefringent particles is n. x , and the refractive index in the fast axis direction of the birefringent particle is n y ; 1.5≤n x ≤2.0, 1.3≤n y ≤1.8, and n x -n y ≥0.002.

[0011] In some embodiments, the particle size of the birefringent particles is (a+b) / 2, 0.001 μm≤(a+b) / 2≤30 μm, wherein a and b represent the minimum length and maximum length of the same birefringent particle, respectively.

[0012] In some embodiments, the mass fraction of the birefringent particles in the depolarization functional layer ranges from 3% to 30%.

[0013] In some embodiments, the thickness of the depolarization functional layer ranges from 5 μm to 40 μm, the thickness of the substrate layer ranges from 10 μm to 150 μm, the transmittance of the substrate layer is greater than or equal to 80%, and the haze of the substrate layer is less than or equal to 5%.

[0014] In some embodiments, the material of the birefringent particles includes at least one of an organic material and an inorganic material;

[0015] The organic material comprises at least one of polyethylene, polypropylene, polystyrene, polyvinyl chloride, cellulose, liquid crystal, protein and polylactic acid;

[0016] The inorganic material includes at least one of silicon dioxide, talc, kaolin, titanium dioxide, wollastonite, vermiculite, aluminum hydroxide, calcium carbonate, magnesium hydroxide, aluminum oxide and mica.

[0017] In some embodiments, the material of the main body layer includes at least one of acrylate copolymer, polyurethane acrylic resin, silicone resin, epoxy acrylate, urethane and natural rubber;

[0018] The material of the substrate layer includes at least one of triacetyl cellulose, polyethylene terephthalate, polycarbonate, polymethyl methacrylate, polycycloolefin and polyethylene naphthalate.

[0019] According to the second aspect of the present application, a polarizer is provided, which includes a polarizing functional layer, a first substrate layer and the depolarizing functional layer described above; the first substrate layer is located between the polarizing functional layer and the depolarizing functional layer, and the absorption axis of the polarizing functional layer is parallel to the winding direction of the substrate layer.

[0020] In some embodiments, the polarizer further includes an optical functional layer located on a side of the depolarization functional layer away from the first substrate layer;

[0021] The optical functional layer includes any one or more combinations of an anti-glare coating, a transparent hardened coating, an anti-reflective coating, an anti-fingerprint coating, and an anti-static coating; or the optical functional layer includes a second substrate layer and any one or more combinations of an anti-glare coating, a transparent hardened coating, an anti-reflective coating, an anti-fingerprint coating, and an anti-static coating located on a side of the second substrate layer facing away from the depolarization functional layer;

[0022] When the optical functional layer includes the anti-reflection layer, the anti-reflection layer is located on a surface of the optical functional layer away from the depolarization functional layer.

[0023] According to a third aspect of the present application, a display device is further provided, comprising a display panel and the polarizer described above located on a light-emitting side of the display panel.

[0024] In the optical film, polaroid and display device of the embodiment of the present application, by aligning the birefringent particles in the depolarization functional layer, the angle between the slow axis direction of the birefringent particles and the winding direction of the substrate layer is greater than or equal to 35° and less than or equal to 55°, so that the linear polarization incident on the optical film can be converted into circular polarization and / or elliptically polarized light by the depolarization functional layer. Therefore, when the optical film is applied to the upper polarizer of the liquid crystal display device, the linear polarization emitted from the upper polarizer of the liquid crystal display device can be converted into circular polarization and / or elliptically polarized light, so that the outgoing light of the liquid crystal display device has an optical property similar to that of natural light that is uniformly distributed in all directions, thereby having an eye protection effect. Moreover, compared with the existing 1 / 4 wave plate and high in-plane retardation (in-plane retardation ≥ 8000nm) transparent substrate layer for depolarization, the material of the depolarization functional layer provided by the embodiment of the present application is easier to obtain, and the orientation of the birefringent particles is also easy to achieve, so that the process of the depolarization functional layer is simpler, the cost is lower and the yield is higher. Therefore, the embodiments of the present application can achieve the depolarization effect through a method with simpler process, lower cost and higher yield, thereby achieving the effect of eye protection.

[0025] Other features and advantages of the present application will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] To more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present application. Those skilled in the art can also derive other drawings based on these drawings without inventive effort.

[0027] In order to more completely understand the present application and its beneficial effects, the following description will be given in conjunction with the accompanying drawings, wherein the same drawing numbers represent the same parts in the following description.

[0028] Figure 1 1 is a schematic diagram of a cross-sectional structure of an optical film provided in an embodiment of the present application;

[0029] Figure 2 Schematic diagram of the structure of a rolled depolarization functional layer provided in an embodiment of the present application;

[0030] Figure 3 Schematic diagram of the structure of another rolled depolarization functional layer provided in an embodiment of the present application;

[0031] Figure 4 1 is a schematic diagram of the cross-sectional structure of a polarizer provided in an embodiment of the present application;

[0032] Figures 5 to 18Schematic diagrams of the cross-sectional structures of several other polarizers provided in the embodiments of the present application;

[0033] Figure 19 1 is a schematic diagram of the cross-sectional structure of a comparative polarizer provided in an embodiment of the present application;

[0034] Figure 20 It is a schematic diagram of the cross-sectional structure of a display device provided in an embodiment of the present application.

[0035] Explanation of the accompanying symbols: 1. optical film; 2. substrate layer; 2a. long side; 2b. short side; 3. depolarization functional layer; 4. main layer; 5. birefringent particles; 6. polarizer; 7. polarizing functional layer; 7a. compensation film; 7b. polarizing layer; 8. first substrate layer; 9. adhesive layer; 10. release film; 11. optical functional layer; 11a. anti-glare coating; 11b. transparent hardening coating; 11c. anti-reflection coating; 11d. low-reflection coating; 12. second substrate layer; 13. contrast polarizer; 14. contrast optical layer; 15. display device; 16. display panel; 17. upper polarizer; 18. lower polarizer. DETAILED DESCRIPTION

[0036] 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 creative work are within the scope of protection of this application.

[0037] like Figures 1 to 3 As shown, an embodiment of the present application provides an optical film 1, which includes a substrate layer 2 and a depolarization functional layer 3 located on one side of the substrate layer 2. The depolarization functional layer 3 includes at least one main layer 4 and birefringent particles 5 dispersed in the at least one main layer 4. The angle θ between the slow axis direction B of the birefringent particles 5 and the winding direction A of the substrate layer 2 is greater than or equal to 35° and less than or equal to 55°; when linearly polarized light is incident on the optical film 1, the linearly polarized light is converted into circularly polarized light and / or elliptically polarized light by the depolarization functional layer 3.

[0038] It will be understood that linear polarization refers to linearly polarized light, circular polarization refers to circularly polarized light, and elliptically polarization refers to elliptically polarized light.

[0039] In some embodiments, the projections of the main layer 4 and the substrate layer 2 in a direction perpendicular to the optical film 1 completely overlap.

[0040] In some embodiments, the main layer 4 in the depolarization functional layer 3 is only one layer, and the birefringent particles 5 are dispersed in the main layer 4 .

[0041] In other embodiments, the main body layer 4 in the depolarization functional layer 3 has multiple layers (greater than or equal to two layers), the multiple main body layers 4 are stacked on the substrate layer 2, and birefringent particles 5 are dispersed in at least one main body layer 4. Figure 1 In the figure, only a single-layer main body layer 4 is taken as an example, but it is not limited to this.

[0042] In a specific embodiment, taking the depolarization functional layer 3 having two main layers as an example, the main layer 4 in the depolarization functional layer 3 includes a first main layer and a second main layer stacked together, and the first main layer is located on a side of the second main layer close to the substrate layer 2 or on a side away from the substrate layer 2, wherein birefringent particles 5 are dispersed in the first main layer, and the second main layer does not contain birefringent particles 5, or the first main layer does not contain birefringent particles 5, and birefringent particles 5 are dispersed in the second main layer.

[0043] It can be understood that the embodiment of the present application does not limit the number of main body layers.

[0044] Usually, such as Figure 2 As shown in Figure 3, for the convenience of storage, the substrate layer 2 and the optical film 1 produced in the factory are both arranged in a roll, and the substrate layer 2 and the optical film 1 can be rolled along the winding direction A and unwound along the unwinding direction (not shown in the figure). It can be understood that the winding direction A and the unwinding direction are parallel to and opposite to each other. In the embodiment of the present application, the winding direction A and the unwinding direction of the substrate layer 2 are defined as the extension direction of the long side 2a of the substrate layer 2, wherein the long side 2a and the short side 2b of the substrate layer 2 are as shown in Figure 3. Figure 2 and Figure 3 It is understood that since the optical film 1 of the embodiment of the present application is composed of a substrate layer 2 and a depolarization functional layer 3 covering the surface of the substrate layer 2, the winding direction A of the substrate layer 2 is the same as the winding direction A of the optical film 1.

[0045] In some embodiments, the winding direction A may also be referred to as the machine direction (MD), that is, the winding direction A is the machine running direction, ie, the long side direction of the film layer.

[0046] For ease of description, the angle θ between the slow axis direction B of the birefringent particles 5 and the winding direction A of the substrate layer 2 is called the alignment angle, and the process of converting linear polarization into circular polarization and / or elliptically polarized light is called depolarization.

[0047] In some embodiments, the testing method of the alignment angle of the birefringent particles 5 in the optical film 1 is as follows: the optical film 1 is placed between two polarizers with a light source at the bottom and whose absorption axes are orthogonal to each other. In the initial state, the winding direction A of the optical film 1 is parallel to the absorption axis of the polarizer on the side close to the light source, and then the optical film 1 is rotated counterclockwise or clockwise between 0° and 90°. The angle when the light-emitting side reaches maximum brightness is the alignment angle.

[0048] In the embodiment of the present application, since the birefringent particles 5 in the depolarization functional layer 3 have an orientation angle, and the orientation angle is greater than or equal to 35° and less than or equal to 55°, the linear polarization incident on the optical film 1 can be converted into circular polarization and / or elliptically polarized light by the depolarization functional layer 3. Therefore, when the optical film 1 is applied to the upper polarizer in the liquid crystal display device, the linear polarization emitted from the upper polarizer of the liquid crystal display device can be converted into circular polarization and / or elliptically polarized light, so that the outgoing light of the liquid crystal display device has an optical property similar to that of natural light that is uniformly distributed in all directions, thereby having an eye protection effect. In addition, compared with the existing 1 / 4 wave plate and high in-plane retardation (in-plane retardation ≥ 8000nm) transparent substrate layer for depolarization, the process of the depolarization functional layer 3 provided in the embodiment of the present application is simpler, lower in cost and higher in yield.

[0049] In some embodiments, the refractive index of visible light in the slow axis direction B of the birefringent particle 5 is n. x , and the refractive index in the fast axis direction (not shown in the figure) of the birefringent particle 5 is n y ; 1.5≤n x ≤2.0, 1.3≤n y ≤1.8, and n x -n y ≥0.002.

[0050] In one embodiment, the visible light is light with a wavelength of 589 nanometers, but is not limited thereto.

[0051] It can be understood that the slow axis direction B of the birefringent particles 5 is the direction of the larger refractive index, and the fast axis direction of the birefringent particles 5 is the direction of the smaller refractive index. The refractive index difference between the slow axis direction B and the fast axis direction of the birefringent particles 5 brings about a light conversion effect. When the alignment angle of the birefringent particles 5 in the depolarization functional layer 3 is greater than or equal to 35° and less than or equal to 55°, linear polarization can be effectively converted into circular polarization and / or elliptically polarized light.

[0052] It should be noted that the light conversion effect of the depolarization functional layer 3 is related to the refractive index difference between the slow axis direction B and the fast axis direction of the birefringent particles 5. When the refractive index difference between the slow axis direction B and the fast axis direction of the birefringent particles 5 is small, it is necessary to increase the thickness of the depolarization functional layer 3 to improve the light conversion effect.

[0053] In some embodiments, the particle size of the birefringent particle 5 is (a+b) / 2, 0.001 μm≤(a+b) / 2≤30 μm, where a and b represent the minimum length and maximum length of the same birefringent particle 5 , respectively.

[0054] It should be noted that the embodiment of the present application does not limit the shape of the birefringent particles 5 .

[0055] In some embodiments, when the particle size of the birefringent particles 5 exceeds 380 nm, the depolarization functional layer 3 has an anti-glare effect and can be used in polarizers or other optical products instead of the anti-glare coating 11 a.

[0056] In some embodiments, the mass fraction of the birefringent particles 5 in the depolarization functional layer 3 ranges from 3% to 30%. For example, the mass fraction of the birefringent particles 5 in the depolarization functional layer 3 is 3%, 5%, 8%, 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, or 30%.

[0057] If the mass fraction of birefringent particles 5 in the depolarization layer 3 is too low, the depolarization effect will be poor or even nonexistent. If the mass fraction of birefringent particles 5 in the depolarization layer 3 is too high, the transmittance of the depolarization layer 3 will decrease, hindering the improvement of transmittance. Therefore, in the embodiment of the present application, controlling the mass fraction of birefringent particles 5 within the range of 3% to 30% effectively achieves the depolarization effect while maintaining a high transmittance of the depolarization layer 3.

[0058] In some embodiments, the depolarization functional layer 3 has a thickness ranging from 5 μm to 40 μm.

[0059] It is understandable that in order to ensure that the depolarization functional layer 3 has a good depolarization effect, the thickness of the depolarization functional layer 3 can be adjusted according to the difference in refractive index between the selected birefringent particles 5 in the slow axis direction B and the fast axis direction, so that the depolarization functional layer 3 has both high transmittance and good depolarization effect.

[0060] In some embodiments, the thickness of the substrate layer 2 ranges from 10 μm to 150 μm; the light transmittance of the substrate layer 2 is greater than or equal to 80%, and the haze of the substrate layer 2 is less than or equal to 5%. By controlling the thickness and haze of the substrate layer 2, the light transmittance of the substrate layer 2 can be effectively improved, resulting in the optical film 1 having a higher light transmittance.

[0061] In some embodiments, the material of the birefringent particles 5 includes at least one of an organic material and an inorganic material. In other words, the material of the birefringent particles 5 can be an organic material, an inorganic material, or a mixture of organic and inorganic materials.

[0062] In some embodiments, the organic material used to make the birefringent particles 5 includes at least one of polyethylene, polypropylene, polystyrene, polyvinyl chloride, cellulose, liquid crystal, protein, and polylactic acid.

[0063] In some embodiments, the inorganic material used to make the birefringent particles 5 includes at least one of silicon dioxide, talc, kaolin, titanium dioxide, wollastonite, vermiculite, aluminum hydroxide, calcium carbonate, magnesium hydroxide, aluminum oxide, and mica.

[0064] In some embodiments, the material of the main body layer 4 of the depolarization functional layer 3 includes at least one of acrylate copolymer, polyurethane acrylic resin, silicone resin, epoxy acrylate, urethane, and natural rubber.

[0065] It can be understood that since the materials of the birefringent particles 5 and the main layer 4 are relatively easy to obtain, the cost of the depolarization functional layer 3 is relatively low.

[0066] In some embodiments, the depolarization functional layer 3 is cured by at least one of thermal curing and photocuring. It is understood that the birefringent particles 5 are dispersed in the aforementioned resin material, and the depolarization functional layer 3 is formed by film formation and curing of the resin. The present embodiment of the present invention does not limit the resin film formation method.

[0067] In some embodiments, the alignment of the birefringent particles 5 may be mechanical alignment, such as blade coating alignment, spray coating alignment, slit extrusion alignment, lip coating alignment, dimple alignment, etc., but not limited thereto.

[0068] In other embodiments, the alignment of the birefringent particles 5 may be photo-alignment, such as ultraviolet (UV) alignment or electron beam (EB) alignment, but not limited thereto.

[0069] Of course, in other embodiments, the alignment of the birefringent particles 5 may also be electric field alignment or magnetic field alignment, which is not limited in the embodiment of the present application.

[0070] It can be understood that since the alignment method of the birefringent particles 5 is relatively easy to implement, the manufacturing process of the depolarization functional layer 3 and the optical film 1 is relatively simple, which is beneficial to further reduce the cost and improve the alignment yield.

[0071] In some embodiments, the material of the main layer 4 of the depolarization functional layer 3 further includes a leveling agent and other functional additives, wherein the material of the leveling agent includes silicone, fluorine, fluorocarbon, etc.

[0072] In some embodiments, the material of the substrate layer 2 of the optical film 1 includes at least one of triacetyl cellulose (TAC), polyethylene terephthalate (PET), polycarbonate (PC), polymethyl methacrylate (PMMA), cycloolefin (Cyclo Olefin Polymer / Cyclo-Olefin Copolymer, COP / COC) and polyethylene naphthalate (PEN).

[0073] In some embodiments, the optical film 1 further includes an optical functional layer 11 located on the side of the depolarization functional layer 3 away from the substrate layer 2, and the optical functional layer 11 includes an anti-glare (AG) coating 11a, a transparent hardening (CHC) coating 11b, an anti-reflection (AR) coating 11c, an anti-fingerprint (AF) coating and an anti-static (AS) coating. Any one or more combinations thereof. The anti-reflection coating 11c can be replaced with a low-reflectivity (LR) coating 11d, and when the optical functional layer 11 includes a low-reflection or anti-reflection layer, the low-reflection or anti-reflection layer is located on the surface of the optical functional layer 11 away from the depolarization functional layer 3, that is, the anti-reflection layer is located on the surface of the light-emitting side of the optical film 1.

[0074] In some embodiments, the depolarization performance of the optical film 1 provided in the embodiments of the present application is tested by the following method: the optical film 1 provided in the embodiments of the present application is placed on a polarizer, and the winding direction A of the optical film 1 is parallel to the absorption axis direction of the polarizer; the stacked optical film 1 and the polarizer are placed above the light source, and then another polarizer (i.e., an analyzer) is placed in the light emitting direction of the optical film 1 (i.e., the side of the optical film 1 away from the polarizer); the analyzer is rotated, and the maximum brightness (Imax) and the minimum brightness (Imin) of the optical film 1 in the light emitting direction are recorded. The ratio of the two (Imax / Imin) is called the depolarization ratio, and the depolarization performance of the optical film 1 is judged by the size of the depolarization ratio.

[0075] It should be noted that, the closer the value of the depolarization ratio (Imax / Imin) is to 1, the better the depolarization performance of the optical film 1 is.

[0076] In some embodiments, when the depolarization ratio (Imax / Imin) is greater than or equal to 1 and less than or equal to 10, it indicates that the optical film 1 has a better depolarization effect.

[0077] In some embodiments, when the optical film 1 or the depolarization functional layer 3 is applied to a polarizer, it is only necessary to control the winding direction A of the substrate layer 2 in the depolarization functional layer 3 to be parallel to the absorption axis of the polarizer. The process is simple, so that the production cost of the polarizer with depolarization function is low and the yield is high.

[0078] In the embodiment of the present application, by aligning the birefringent particles 5 in the depolarization functional layer 3, the birefringent particles 5 have an alignment angle, and the alignment angle is greater than or equal to 35° and less than or equal to 55°, so that the linear polarization incident on the optical film 1 can be converted into circular polarization and / or elliptically polarized light by the depolarization functional layer 3. Therefore, when the optical film 1 is applied to the upper polarizer of the liquid crystal display device, the linear polarization emitted from the upper polarizer of the liquid crystal display device can be converted into circular polarization and / or elliptically polarized light, so that the outgoing light of the liquid crystal display device has an optical property similar to that of natural light that is uniformly distributed in all directions, thereby having an eye protection effect. In addition, compared with the existing 1 / 4 wave plate and high in-plane retardation (in-plane retardation ≥ 8000nm) transparent substrate layer for depolarization, the material of the depolarization functional layer 3 provided in the embodiment of the present application is easier to obtain, and the alignment of the birefringent particles 5 is also easy to achieve, making the process of the depolarization functional layer 3 simpler, lower in cost and higher in yield. Therefore, the embodiments of the present application can achieve the depolarization effect through a method with simpler process, lower cost and higher yield, thereby achieving the effect of eye protection.

[0079] like Figure 4 As shown, the embodiment of the present application further provides a polarizer 6, which includes a polarizing functional layer 7, a first substrate layer 8, and the depolarizing functional layer 3 described in the above embodiment. The first substrate layer 8 is located between the polarizing functional layer 7 and the depolarizing functional layer 3, and the absorption axis of the polarizing functional layer 7 is parallel to the winding direction of the first substrate layer 8.

[0080] It should be noted that the outermost substrate layer of the existing polarizer 6 can be directly replaced by the optical film 1, so that the polarizing functional layer 7 of the polarizer 6 is provided with a substrate layer 2 (i.e., the first substrate layer 8) and a depolarizing functional layer 3 in sequence; or an adhesive layer can be used to separately adhere the depolarizing functional layer 3 to the surface of the outermost substrate layer of the polarizer 6; regardless of which method is used, the absorption axis of the polarizing functional layer 7 of the improved polarizer 6 is parallel to the winding direction A of the depolarizing functional layer 3 (or substrate layer 2), so that the light-emitting side of the improved polarizer 6 has a depolarizing function. Therefore, the first substrate layer 8 in the polarizer 6 can be the substrate layer 2 in the optical film 1 in the aforementioned embodiment, or it can be the substrate layer provided on the polarizing functional layer 7, and the embodiments of the present application do not limit this.

[0081] When the optical film 1 is directly arranged on the polarizing functional layer 7 of the polarizer 6, the first substrate layer 8 is the substrate layer 2. At this time, the material, thickness, transmittance, haze and other characteristics of the first substrate layer 8 can refer to the relevant description of the aforementioned substrate layer 2 and will not be repeated here.

[0082] When the depolarization functional layer 3 is separately attached to the side of the first substrate layer 8 of the polarizer 6 away from the polarization functional layer 7, the material of the first substrate layer 8 and the substrate layer 2 in the optical film 1 in the aforementioned embodiment can be the same or different, which is not limited here.

[0083] In some embodiments, the polarizing functional layer 7 includes a compensation film 7 a and a polarizing layer 7 b , and the polarizing layer 7 b is located between the compensation film 7 a and the first substrate layer 8 .

[0084] In some embodiments, the material of the polarizing layer 7b includes polyvinyl alcohol (PVA), but is not limited thereto.

[0085] In some embodiments, the material of the polarizing layer 7 b further includes a dye, so that the polarizer 6 has a specific color.

[0086] In some embodiments, the polarizer 6 further includes an adhesive layer 9 and a release film 10 located on the side of the polarizing functional layer 7 facing away from the first substrate layer 8, and the adhesive layer 9 is located between the polarizing functional layer 7 and the release film 10. It will be understood that when the polarizer 6 is used, the release film 10 is removed, so that the polarizer 6 is fixedly connected to other structures through the adhesive layer 9.

[0087] In some embodiments, the material of the adhesive layer 9 includes pressure sensitive adhesives (PSA), but is not limited thereto.

[0088] In some embodiments, the polarizer 6 further includes an optical functional layer 11 located on the side of the depolarization functional layer 3 facing away from the first substrate layer 8. The optical functional layer 11 includes any one or more of an anti-glare coating 11a, a transparent hardened coating 11b, an anti-reflective coating 11c, an anti-fingerprint coating, and an anti-static coating. The anti-reflective coating 11c may also be replaced with a low-reflective coating 11d.

[0089] In other embodiments, the optical functional layer 11 may further include a second substrate layer 12, and any one or more combinations of the anti-glare coating 11a, the transparent hardened coating 11b, the anti-reflective coating 11c, the low-reflective coating 11d, the anti-fingerprint coating, and the anti-static coating are located on the side of the second substrate layer 12 facing away from the depolarization functional layer 3. It is understood that in this case, the depolarization functional layer 3 is sandwiched between the first substrate layer 8 and the second substrate layer 12.

[0090] When the optical function layer 11 includes the low-reflection coating 11 d or the anti-reflection coating 11 d , the low-reflection coating 11 d or the anti-reflection coating 11 d is located on the surface of the optical function layer 11 away from the depolarization function layer 3 .

[0091] In a specific embodiment, if Figure 4 As shown, the polarizer 6 includes a release film 10, an adhesive layer 9, a compensation film 7a, a polarizing layer 7b, a first substrate layer 8 and a depolarization functional layer 3 from bottom to top, so that the light-emitting side of the polarizer 6 has a depolarization effect.

[0092] In a specific embodiment, if Figure 5 As shown, the polarizer 6 includes, from bottom to top, a release film 10, an adhesive layer 9, a compensation film 7a, a polarizing layer 7b, a first substrate layer 8, a depolarization layer 3, and an anti-glare coating 11a, thereby providing depolarization and anti-glare effects on the light-emitting side of the polarizer 6. It will be appreciated that when the particle size of the birefringent particles 5 in the depolarization layer 3 exceeds 380 nm, the depolarization layer 3 provides an anti-glare effect and can therefore replace the anti-glare coating 11a. In this case, the anti-glare coating 11a is not required, and the polarizer 6 still maintains the depolarization and anti-glare effects.

[0093] In a specific embodiment, if Figure 6 As shown, the polarizer 6 includes, from bottom to top, a release film 10, an adhesive layer 9, a compensation film 7a, a polarizing layer 7b, a first substrate layer 8, a depolarization functional layer 3 and a transparent hardened coating 11b, so that the light-emitting side of the polarizer 6 has depolarization and anti-scratch effects.

[0094] In a specific embodiment, if Figure 7 As shown, the polarizer 6 includes, from bottom to top, a release film 10, an adhesive layer 9, a compensation film 7a, a polarizing layer 7b, a first substrate layer 8, a depolarization functional layer 3 and an anti-reflection coating 11c, so that the light-emitting side of the polarizer 6 has depolarization and anti-reflection effects.

[0095] In a specific embodiment, if Figure 8 As shown, the polarizer 6 includes, from bottom to top, a release film 10, an adhesive layer 9, a compensation film 7a, a polarizing layer 7b, a first substrate layer 8, a depolarization functional layer 3 and a low-reflection coating 11d, so that the light-emitting side of the polarizer 6 has the effect of depolarization and reducing reflectivity.

[0096] In a specific embodiment, if Figure 9 As shown, the polarizer 6 includes, from bottom to top, a release film 10, an adhesive layer 9, a compensation film 7a, a polarizing layer 7b, a first substrate layer 8, a depolarization functional layer 3, a transparent hardening coating 11b and a low-reflection coating 11d, so that the light-emitting side of the polarizer 6 has the effects of depolarization, scratch resistance and reduced reflectivity.

[0097] In a specific embodiment, if Figure 10 As shown, the polarizer 6 includes, from bottom to top, a release film 10, an adhesive layer 9, a compensation film 7a, a polarizing layer 7b, a first substrate layer 8, a depolarization functional layer 3, a transparent hardening coating 11b and an anti-reflection coating 11c, so that the light-emitting side of the polarizer 6 has depolarization, anti-scratch and anti-reflection effects.

[0098] In a specific embodiment, if Figure 11 As shown, the polarizer 6 includes, from bottom to top, a release film 10, an adhesive layer 9, a compensation film 7a, a polarizing layer 7b, a first substrate layer 8, a depolarization functional layer 3, an anti-glare coating 11a and a low-reflection coating 11d, so that the light-emitting side of the polarizer 6 has the effects of depolarization, anti-glare and reduced reflectivity.

[0099] In a specific embodiment, if Figure 12 As shown, the polarizer 6 includes, from bottom to top, a release film 10, an adhesive layer 9, a compensation film 7a, a polarizing layer 7b, a first substrate layer 8, a depolarization functional layer 3, an anti-glare coating 11a and an anti-reflection coating 11c, so that the light-emitting side of the polarizer 6 has depolarization, anti-glare and anti-reflection effects.

[0100] In a specific embodiment, if Figure 13 As shown, the polarizer 6 includes, from bottom to top, a release film 10, an adhesive layer 9, a compensation film 7a, a polarizing layer 7b, a first substrate layer 8, a depolarization functional layer 3, a second substrate layer 12 and a transparent hardened coating 11b, so that the light-emitting side of the polarizer 6 has depolarization and anti-scratch effects.

[0101] In a specific embodiment, if Figure 14 As shown, the polarizer 6 includes, from bottom to top, a release film 10, an adhesive layer 9, a compensation film 7a, a polarizing layer 7b, a first substrate layer 8, a depolarization functional layer 3, a second substrate layer 12 and an anti-glare coating 11a, so that the light-emitting side of the polarizer 6 has depolarization and anti-glare effects.

[0102] In a specific embodiment, if Figure 15 As shown, the polarizer 6 includes, from bottom to top, a release film 10, an adhesive layer 9, a compensation film 7a, a polarizing layer 7b, a first substrate layer 8, a depolarization functional layer 3, a second substrate layer 12, a transparent hardening coating 11b and a low-reflection coating 11d, so that the light-emitting side of the polarizer 6 has the effects of depolarization, scratch resistance and reduced reflectivity.

[0103] In a specific embodiment, if Figure 16 As shown, the polarizer 6 includes, from bottom to top, a release film 10, an adhesive layer 9, a compensation film 7a, a polarizing layer 7b, a first substrate layer 8, a depolarization functional layer 3, a second substrate layer 12, a transparent hardening coating 11b and an anti-reflection coating 11c, so that the light-emitting side of the polarizer 6 has depolarization, anti-scratch and anti-reflection effects.

[0104] In a specific embodiment, if Figure 17 As shown, the polarizer 6 includes, from bottom to top, a release film 10, an adhesive layer 9, a compensation film 7a, a polarizing layer 7b, a first substrate layer 8, a depolarization functional layer 3, a second substrate layer 12, an anti-glare coating 11a and a low-reflection coating 11d, so that the light-emitting side of the polarizer 6 has the effects of depolarization, anti-glare and reduced reflectivity.

[0105] In a specific embodiment, if Figure 18 As shown, the polarizer 6 includes, from bottom to top, a release film 10, an adhesive layer 9, a compensation film 7a, a polarizing layer 7b, a first substrate layer 8, a depolarization functional layer 3, a second substrate layer 12, an anti-glare coating 11a and an anti-reflection coating 11c, so that the light-emitting side of the polarizer 6 has depolarization, anti-glare and anti-reflection effects.

[0106] It is understandable that the polarizer 6 provided in the embodiment of the present application is not limited to the types listed above, that is, the embodiment of the present application does not limit the combination of multiple types of optical functional layers 11.

[0107] As shown in Table 1, the present invention provides eight polarizers 6 through Examples 1 to 8, and provides three comparative polarizers 13 through Comparative Examples 1 to 3. The present invention tests the optical properties of the eight polarizers 6 and the comparative polarizer 13, and the results are shown in Table 1.

[0108] The structure of the polarizer 6 provided in Examples 1 to 8 is as follows: Figure 4 As shown, the polarizer 6 includes a release film 10, a glue layer 9, a compensation film 7a, a polarizing layer 7b, a first substrate layer 8 and a depolarization functional layer 3 from bottom to top. The structure of the comparative polarizer 13 in Comparative Examples 1 to 3 is as follows Figure 19As shown, the contrast polarizer 13 includes, from bottom to top, a release film 10, an adhesive layer 9, a compensation film 7a, a polarizing layer 7b, a first substrate layer 8 and a contrast optical layer 14, wherein the contrast optical layer 14 is composed of a main layer 4 and contrast particles dispersed in the main layer 4.

[0109] Table 1

[0110]

[0111] The parameters of the first substrate layer 8, birefringent particles 5 and depolarization functional layer 3 in the polarizer 6 provided in Examples 1 to 8, and the first substrate layer 8, comparative particles and comparative optical layer 14 in the comparative polarizer 13 provided in Comparative Examples 1 to 3 are shown in Table 1.

[0112] It should be noted that the optical properties of the polarizer 6 and the comparative polarizer 13 in Table 1 are measured according to the depolarization performance test method described in the aforementioned embodiment. That is, the depolarization ratio in Table 1 is measured according to the depolarization performance test method described in the aforementioned embodiment.

[0113] As shown in Table 1, the polarizers 6 provided in Examples 1 to 8 have at least partially different materials and thicknesses for the first substrate layer 8, different refractive index differences between the slow and fast axis directions of the materials of the birefringent particles 5, at least partially different particle sizes of the birefringent particles 5, and at least partially different thicknesses and contents of the depolarization functional layer 3. In Examples 1 to 8, the alignment angles of the birefringent particles 5 in the depolarization functional layer 3 are all between 35° and 55°, and the depolarization ratios of these polarizers 6 are all between 1 and 10, indicating that the light-exiting side of these polarizers 6 has good depolarization performance.

[0114] As can be seen from Table 1, the comparative particles (calcium hydroxide particles) in the comparative optical layer 14 of the comparative polarizer 13 provided in Comparative Example 1 do not belong to the birefringent particles 5, so the comparative particles do not have an alignment angle, and the corresponding depolarization ratio of the comparative polarizer 13 is 131.17, which is much larger than the depolarization ratio of the polarizer 6 provided in Examples 1 to 8, indicating that the light-emitting side of the comparative polarizer 13 provided in Comparative Example 1 does not have a depolarization effect. Although birefringent particles made of talc are added to the comparative optical layer 14 of the comparative polarizers 13 provided in Comparative Examples 2 and 3, the alignment angles of the birefringent particles are 30° and 60°, respectively, which are not within the alignment angle range protected by this application. The corresponding depolarization ratios of the comparative polarizers 13 are both 43.34, which are also much larger than the depolarization ratio of the polarizer 6 provided in Examples 1 to 8, indicating that the light-emitting side of the comparative polarizers 13 provided in Comparative Examples 2 and 3 also does not have a depolarization effect or has a poor depolarization effect.

[0115] As can be seen from Table 1, the depolarization functional layer 3 provided in the embodiment of the present application uses birefringent particles, and by controlling the content and alignment angle of the birefringent particles, a good depolarization effect can be achieved. However, the comparative optical layer 14 provided in Comparative Example 1 does not use birefringent particles and therefore has no depolarization effect. Although the comparative optical layers 14 provided in Comparative Examples 2 and 3 use birefringent particles, the depolarization effect is poor because the alignment angles of the birefringent particles are not within the range of 35° to 55°.

[0116] In the embodiment of the present application, since the polarizer 6 includes a depolarization layer 3, linear polarization can be converted into circular and / or elliptically polarized light. When the polarizer 6 is applied to the light-emitting side of a display panel in a display device, the light emitted by the display device has optical properties similar to natural light, with uniform distribution in all directions, thereby providing eye protection. Furthermore, since the process of providing the depolarization layer 3 in the polarizer 6 is relatively simple and has a high yield, the production cost of the display device can be reduced and the yield of the display device can be improved.

[0117] like Figure 20 As shown, an embodiment of the present application further provides a display device 15, which includes a display panel 16 and an upper polarizer 17 located on the light-emitting side of the display panel 16. The upper polarizer 17 is the polarizer 6 containing the depolarization functional layer 3 described in the aforementioned embodiment, so that the light emitted from the display device 15 is circularly polarized and / or elliptically polarized, thereby playing an eye protection function.

[0118] In some embodiments, the display panel 16 is a liquid crystal display panel, and the backlight layer of the display panel 16 is further provided with a lower polarizer 18 , but the lower polarizer 18 does not need to be provided with a depolarization functional layer 3 .

[0119] In some embodiments, the display device 15 further includes a backlight module located on a side of the lower polarizer 18 facing away from the display panel 16 . The present application does not limit the structure of the backlight module.

[0120] In the embodiment of the present application, because the upper polarizer 17 in the display device 15 includes the depolarization layer 3, linear polarization can be converted into circularly polarized light and / or elliptically polarized light, so that the light emitted by the display device 15 has optical properties similar to natural light, uniformly distributed in all directions, thereby providing eye protection. Furthermore, because the process of providing the depolarization layer 3 in the upper polarizer 17 is relatively simple and has a high yield rate, the production cost of the display device 15 can be reduced and the yield rate of the display device 15 can be improved.

[0121] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0122] 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.

[0123] The embodiments, implementation methods and related technical features of the present application can be combined and replaced with each other without conflict.

[0124] The above are merely preferred embodiments of the present application and do not constitute any form of limitation to the present application. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application are still within the scope of the technical solution of the present application.

Claims

1. An optical film, characterized in that: include: substrate layer; a depolarization functional layer located on one side of the substrate layer; the depolarization functional layer comprises at least one main layer and birefringent particles dispersed in the at least one main layer; The angle between the slow axis direction of the birefringent particles and the winding direction of the substrate layer is greater than or equal to 35° and less than or equal to 55°; when linear polarization is incident on the optical film, the linear polarization is converted into circular polarization and / or elliptically polarized light by the depolarization functional layer.

2. The optical film according to claim 1, wherein: The refractive index of visible light in the slow axis direction of the birefringent particles is n x , and the refractive index in the fast axis direction of the birefringent particle is n y ; 1.5≤n x ≤2.0, 1.3≤n y ≤1.8, and n x -n y ≥0.

002.

3. The optical film according to claim 1, wherein: The particle size of the birefringent particles is (a+b) / 2, 0.001 μm≤(a+b) / 2≤30 μm, wherein a and b represent the minimum length and maximum length of the same birefringent particle, respectively.

4. The optical film according to claim 1, wherein: The mass fraction of the birefringent particles in the depolarization functional layer is in a range of 3% to 30%.

5. The optical film according to any one of claims 1 to 4, characterized in that: The thickness of the depolarization functional layer ranges from 5 μm to 40 μm, and the thickness of the substrate layer ranges from 10 μm to 150 μm; the light transmittance of the substrate layer is greater than or equal to 80%, and the haze of the substrate layer is less than or equal to 5%.

6. The optical film according to any one of claims 1 to 4, characterized in that: The material of the birefringent particles includes at least one of an organic material and an inorganic material; The organic material comprises at least one of polyethylene, polypropylene, polystyrene, polyvinyl chloride, cellulose, liquid crystal, protein and polylactic acid; The inorganic material includes at least one of silicon dioxide, talc, kaolin, titanium dioxide, wollastonite, vermiculite, aluminum hydroxide, calcium carbonate, magnesium hydroxide, aluminum oxide and mica.

7. The optical film according to claim 6, wherein: The material of the main body layer includes at least one of acrylate copolymer, polyurethane acrylic resin, silicone resin, epoxy acrylate, urethane and natural rubber; The material of the substrate layer includes at least one of triacetyl cellulose, polyethylene terephthalate, polycarbonate, polymethyl methacrylate, polycycloolefin and polyethylene naphthalate.

8. A polarizer, characterized in that: It comprises a polarizing functional layer, a first substrate layer and a depolarizing functional layer as described in any one of claims 1 to 7; the first substrate layer is located between the polarizing functional layer and the depolarizing functional layer, and the absorption axis of the polarizing functional layer is parallel to the winding direction of the substrate layer.

9. The polarizer according to claim 8, wherein The polarizer further includes an optical functional layer located on a side of the depolarization functional layer away from the first substrate layer; The optical functional layer includes any one or more combinations of an anti-glare coating, a transparent hardened coating, an anti-reflective coating, an anti-fingerprint coating, and an anti-static coating; or the optical functional layer includes a second substrate layer and any one or more combinations of an anti-glare coating, a transparent hardened coating, an anti-reflective coating, an anti-fingerprint coating, and an anti-static coating located on a side of the second substrate layer facing away from the depolarization functional layer.

10. The polarizer according to claim 9, wherein: When the optical functional layer includes the anti-reflection coating, the anti-reflection coating is located on a surface of the optical functional layer away from the depolarization functional layer.

11. A display device, characterized in that: The invention comprises a display panel and a polarizer as claimed in claim 8, 9 or 10, located on the light-emitting side of the display panel.

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