Optical film having excellent dent resistance and display device including the same

Abstract

One embodiment of the present invention provides an optical film that includes a light-transmitting matrix and a filler dispersed in the light-transmitting matrix, and has a 1 mm crush resistance of 10.7 N or more based on a thickness of 50 μm, and a display device that includes such an optical film.

Description

[Technical Field]

[0001] The present invention relates to an optical film and a display device including the same, and more particularly to an optical film having excellent dent resistance (dent resistance). [Background technology]

[0002] Recently, as display devices have become thinner, lighter, and more flexible, the use of optical films instead of glass as cover windows has been considered. For optical films to be used as cover windows in display devices, they must have excellent mechanical properties in addition to excellent optical properties. For example, optical films must have excellent strength, hardness, abrasion resistance, flexibility, and other properties.

[0003] Fillers may be added to optical films that require various physical properties to provide desired physical properties. The fillers may vary depending on the physical properties required for the optical film. Summary of the Invention [Problem to be solved by the invention]

[0004] One embodiment of the present invention seeks to provide an optical film that includes a fibrous filler dispersed within a light-transmitting matrix.

[0005] Another embodiment of the present invention seeks to provide an optical film with excellent indentation hardness by including a fibrous filler dispersed within a light-transmitting matrix.

[0006] Another embodiment of the present invention seeks to provide an optical film with excellent dent strength by including a fibrous filler dispersed within a light-transmitting matrix.

[0007] Another embodiment of the present invention provides a display device including the optical film. [Means for solving the problem]

[0008] One embodiment of the present invention provides an optical film comprising: a light-transmitting matrix; and a filler dispersed in the light-transmitting matrix, the optical film having a 1 mm dent strength of 10.7 N or more based on a thickness of 50 μm.

[0009] The 1 mm dent strength refers to the force that the optical film resists when pressed 1 mm by a probe in a universal testing machine that presses the optical film vertically at a speed of 5 mm / min.

[0010] The filler according to an embodiment of the present invention may have a rod-like or fibrous shape.

[0011] The filler according to an embodiment of the present invention may have a length of 1 to 10 μm.

[0012] The filler according to one embodiment of the present invention may have a diameter of 3 to 330 nm.

[0013] The filler according to an embodiment of the present invention may have an aspect ratio of 30-1000.

[0014] The aspect ratio is the ratio of the length to the diameter of the filler.

[0015] The filler according to an embodiment of the present invention may include at least one of glass fiber, aluminum-based fiber, titanium fiber, and fluoride fiber.

[0016] The filler according to one embodiment of the present invention may include aluminum oxide hydroxide.

[0017] The content of the filler according to an embodiment of the present invention may be 3 to 50 wt % based on the total weight of the optical film.

[0018] The optical film according to one embodiment of the present invention has a viscosity of 1.55 to 1.67 g / cm 3 The true density may be

[0019] The optical film according to an embodiment of the present invention may have an HM of 220 MPa or more based on a thickness of 50 μm.

[0020] The HM is the Martens hardness of the optical film, and can be measured using HM-2000 under the conditions of 12 mN / running time 12 seconds / hold time 5 seconds.

[0021] The optical film according to an embodiment of the present invention may have an HV of 46 or more based on a thickness of 50 μm.

[0022] The HV is the Vickers hardness of the optical film, and can be measured using HM-2000 under the conditions of 12 mN / running time 12 seconds / hold time 5 seconds.

[0023] The optical film according to an embodiment of the present invention may have a recovery rate (nIT) of 60 to 100%.

[0024] Here, the recovery rate is measured using a nanoindenter under the conditions of 12 mN / 12 seconds (12 s) / Creep 5 seconds (Creep 5 s) / 24° C., 40 RH%.

[0025] According to an embodiment of the present invention, the light-transmitting matrix may include at least one of an imide repeat unit and an amide repeat unit.

[0026] According to one embodiment of the present invention, the light-transmitting matrix may be formed from a polymerizable composition including a diamine-based monomer and at least one of a dianhydride-based compound and a dicarbonyl-based compound.

[0027] The diamine monomers include bistrifluoromethylbenzidine (2,2'-bis(trifluoromethyl) benzidine, TFDB), oxydianiline (4,4'-oxydianiline, ODA), p-phenylenediamine (para-phenylene diamine, pPDA), m-phenylenediamine (meta-phenylene diamine, mPDA), p-methylenediamine (para-Methylene Diamine, pMDA), m-methylenediamine (meta-Methylene Diamine, mMDA), bisaminophenoxybenzene (1,3-bis(3-aminophenoxy) benzene, 133APB), bisaminophenoxybenzene (1,3-bis(4-aminophenoxy) benzene, 134APB), bisaminophenoxyphenyl hexafluoropropane (2,2'-bis[4(4-aminophenoxy)phenyl] hexafluoropropane (4BDAF), bisaminophenyl hexafluoropropane (2,2'-bis(3-aminophenyl) hexafluoropropane (33-6F), bisaminophenyl hexafluoropropane (2,2'-bis(4-aminophenyl) hexafluoropropane (44-6F), bisaminophenyl sulfone (bis(4-aminophenyl) sulfone (4DDS), bisaminophenyl sulfone (bis(3-aminophenyl) sulfone (3DDS), cyclohexanediamine (1,3-cyclohexanediamine (13CHD), cyclohexanediamine (1,4-cyclohexanediamine (14CHD), bisaminophenoxyphenylpropane (2,2-Bis[4-(4-aminophenoxy)-phenyl]propane (6HMDA), bisaminohydroxyphenylhexafluoropropane (2,2-Bis(3-amino-4-hydroxyphenyl)-hexafluoropropane (DBOH)), and bisaminophenoxydiphenylsulfone (4,4'-Bis(3-amino phenoxy)diphenyl sulfone, DBSDA) can be included.

[0028] The dianhydride compounds include biphenyltetracarboxylic dianhydride (3,3,4,4-biphenyltetracarboxylic dianhydride, BPDA), 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA), 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic anhydride (TDA), pyromellitic acid dianhydride (1,2,4,5-benzene tetracarboxylic dianhydride, PMDA), benzophenone tetracarboxylic dianhydride (3,3,4,4-benzophenone tetracarboxylic dianhydride, BTDA), oxydiphthalic dianhydride (4,4-oxydiphthalic The compound may include at least one of 4,4'-bis(3,4-dicarboxyphenoxy)diphenyl sulfide dianhydride (ODPA), bis(3,4dicarboxyphenyl) dimethyl-silane dianhydride (SiDA), bisdicarboxyphenoxydiphenyl sulfide dianhydride (BDSDA), sulfonyldiphthalic anhydride (SO2DPA), cyclobutane-1,2,3,4-tetracarboxylic dianhydride (CBDA), and isopropylidenephenoxy bis(phthalic anhydride) (6HBDA).

[0029] The dicarbonyl compound may include at least one of terephthaloyl chloride (TPC), phthaloyl chloride, isophthaloyl chloride (IPC), 4,4'-biphenyldicarbonyl chloride (DPDOC), 4,4'-oxybis(benzoyl chloride) (OBBOC), naphthalene-2,3-dicarbonyl dichloride, and 1,4-cyclohexanedicabonyl dichloride (CHDOC).

[0030] According to an embodiment of the present invention, the molar ratio of the dianhydride compound to the dicarbonyl compound may be in the range of 5:95 to 40:60.

[0031] Another embodiment of the present invention provides a display device including a display panel and the optical film disposed on the display panel. [Effects of the Invention]

[0032] According to one embodiment of the present invention, the filler contained in the optical film has a rod-like or fibrous shape, and can entangle polymer chains constituting the light-transmitting matrix, thereby improving the mechanical strength of the optical film.

[0033] When an optical film according to an embodiment of the present invention is used in a display device, deformation can be prevented or suppressed when an external force is applied to the display device using, for example, a touch pen, and the resistance to deformation can be improved. Furthermore, when an external force is continuously applied under the same conditions, the degree of deformation can be reduced. [Brief explanation of the drawings]

[0034] [Figure 1] 1 is a schematic diagram of an optical film according to an embodiment of the present invention. [Figure 2] 10 is a cross-sectional view of a portion of a display device according to another embodiment of the present invention. [Figure 3] FIG. 3 is an enlarged cross-sectional view of the "P" portion of FIG. 2. DETAILED DESCRIPTION OF THE INVENTION

[0035] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the embodiments described below are merely for illustrative purposes to help a clear understanding of the present invention, and are not intended to limit the scope of the present invention.

[0036] The shapes, sizes, ratios, angles, numbers, etc. shown in the drawings for illustrating the embodiments of the present invention are merely examples, and the present invention is not limited to the details shown in the drawings. The same components may be designated by the same reference numerals throughout the specification. In describing the present invention, if a detailed description of related well-known technologies is deemed to obscure the gist of the present invention, the detailed description will be omitted.

[0037] When words such as "include," "have," and "be," etc. are used in this specification, other parts may be added unless the expression "only" is used. When an element is indicated in the singular, it includes the plural unless otherwise expressly stated. In addition, when interpreting an element, it is interpreted as including a margin of error even if there is no other explicit statement.

[0038] When describing a positional relationship, for example, when the positional relationship between two parts is described as "above," "on top of," "below," or "to the side," there may be one or more different parts located between the two parts, unless the words "immediately" or "directly" are used.

[0039] Spatially relative terms such as "below," "beneath," "lower," "above," and "upper" may be used to easily describe the relationship of one element or component to another, as illustrated in the figures. Spatially relative terms should be understood to encompass different orientations of elements in use or operation in addition to the orientation depicted in the figures. For example, if an element illustrated in the figures were turned over, an element described as "below" or "beneath" another element would be positioned "above" the other element. Thus, the exemplary term "below" can encompass both an orientation of below and above. Similarly, the exemplary terms "up" or "upper" can encompass both an orientation of above and below.

[0040] When describing a temporal relationship, for example, when the temporal relationship is described as "after", "following", "next to", or "before", it may also include cases where the relationship is not consecutive, unless the expression "directly" or "immediately" is used.

[0041] Although terms such as "first" and "second" are used to describe various components, the components are not limited by these terms. These terms are used to distinguish only one component from another. Therefore, a first component referred to below may also be a second component within the technical concept of the present invention.

[0042] The term "at least one" should be understood to include all possible combinations of one or more related items. For example, "at least one of the first, second, and third items" may refer not only to the first, second, or third item, but also to all possible combinations of two or more of the first, second, and third items.

[0043] The features of the various embodiments of the present invention may be partially or wholly combined or combined with each other, and may be technically interlocked and driven in various ways, and each embodiment may be implemented independently of the others, or may be associated and implemented together.

[0044] FIG. 1 is a schematic diagram of an optical film (100) according to one embodiment of the present invention.

[0045] According to one embodiment of the present invention, the film having optical transparency is called an optical film (100).

[0046] An optical film (100) according to one embodiment of the invention includes a light-transmitting matrix (110) and a filler (120) dispersed in the light-transmitting matrix.

[0047] The light-transmitting matrix 110 has light-transmitting properties. According to one embodiment of the present invention, the light-transmitting matrix 110 may have flexible properties. For example, the light-transmitting matrix 110 may have bending, folding, or rollable properties. As a result, the optical film 100 according to one embodiment of the present invention has light-transmitting properties and may have bending, folding, or rollable properties.

[0048] According to one embodiment of the present invention, the light-transmitting matrix 110 may include at least one of an imide repeat unit and an amide repeat unit.

[0049] The light-transmitting matrix 110 according to an embodiment of the present invention may be manufactured from components including, for example, a dianhydride-based compound and a diamine-based monomer. Specifically, the light-transmitting matrix 110 may include imide repeat units formed by the dianhydride-based compound and the diamine-based monomer.

[0050] However, the light-transmitting matrix 110 according to an embodiment of the present invention is not limited thereto, and the light-transmitting matrix 110 may be made of components including, for example, a dicarbonyl compound and a diamine monomer. Specifically, the light-transmitting matrix 110 may include an amide repeat unit formed by the dicarbonyl compound and the diamine monomer.

[0051] In addition, the light-transmitting matrix 110 according to an embodiment of the present invention may be manufactured from components including a dicarbonyl-based compound in addition to a dianhydride-based compound and a diamine-based monomer. The light-transmitting matrix 110 according to an embodiment of the present invention may have imide repeating units and amide repeating units. An example of the light-transmitting matrix 110 having imide repeating units and amide repeating units is polyamide-imide resin.

[0052] According to an embodiment of the present invention, the light-transmitting matrix 110 may include a polyimide-based polymer. Examples of polyimide-based polymers include polyimide polymers, polyamide-imide polymers, etc. The light-transmitting matrix 110 according to an embodiment of the present invention may be made of, for example, a polyimide-based polymer resin.

[0053] According to one embodiment of the present invention, the light-transmitting matrix 110 may be formed from a polymerizable composition including a diamine-based monomer and at least one of a dianhydride-based compound and a dicarbonyl-based compound.

[0054] The polymerizable composition according to an embodiment of the present invention may include a diamine-based monomer.

[0055] According to an embodiment of the present invention, the diamine-based monomer may be, for example, bistrifluoromethylbenzidine (2,2'-bis(trifluoromethyl)benzidine, TFDB), oxydianiline (4,4'-oxydianiline, ODA), p-phenylenediamine (para-phenylene diamine, pPDA), m-phenylenediamine (meta-phenylene diamine, mPDA), p-methylenediamine (para-Methylene Diamine, pMDA), m-methylenediamine (meta-Methylene Diamine, mMDA), bisaminophenoxybenzene (1,3-bis(3-aminophenoxy)benzene, 133APB), bisaminophenoxybenzene (1,3-bis(4-aminophenoxy)benzene, 134APB), bisaminophenoxyphenyl hexafluoropropane (2,2'-bis[4(4-aminophenoxy)phenyl] hexafluoropropane (4BDAF), bisaminophenyl hexafluoropropane (2,2'-bis(3-aminophenyl)hexafluoropropane (33-6F), bisaminophenyl hexafluoropropane (2,2'-bis(4-aminophenyl)hexafluoropropane (44-6F), bisaminophenyl sulfone (bis(4-aminophenyl)sulfone (4DDS), bisaminophenyl sulfone (bis(3-aminophenyl)sulfone (3DDS), Cyclohexyl The following compounds were used: 1,3-Cyclohexanediamine (13CHD), 1,4-Cyclohexanediamine (14CHD), 2,2-Bis[4-(4-aminophenoxy)-phenyl]propane (6HMDA), 2,2-Bis(3-amino-4-hydroxyphenyl)-hexafluoropropane (DBOH), and bisaminophenoxydiphenylsulfone (4,4'-Bis(3-amino phenoxy) diphenyl sulfone, DBSDA) can be included.

[0056] More specifically, according to one embodiment of the present invention, the diamine-based monomer may include at least one of bistrifluoromethylbenzidine (2,2'-bis(trifluoromethyl)benzidine, TFDB), bisaminophenylhexafluoropropane (2,2'-bis(3-aminophenyl)hexafluoropropane, 33-6F), bisaminophenylhexafluoropropane (2,2'-bis(4-aminophenyl)hexafluoropropane, 44-6F), bisaminophenylsulfone (4DDS), bisaminophenylsulfone (3DDS), and bisaminophenoxydiphenylsulfone (4,4'-Bis(3-amino phenoxy)diphenylsulfone, DBSDA). However, one embodiment of the present invention is not limited thereto.

[0057] The polymerizable composition according to an embodiment of the present invention may include at least one of a dianhydride-based compound and a dicarbonyl-based compound.

[0058] According to an embodiment of the present invention, the dianhydride-based compound may be, for example, biphenyltetracarboxylic dianhydride (3,3,4,4-biphenyltetracarboxylic dianhydride, BPDA), 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA), 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic anhydride (TDA), pyromellitic acid dianhydride (1,2,4,5-benzene tetracarboxylic dianhydride, PMDA), benzophenone tetracarboxylic dianhydride (3,3,4,4-benzophenone tetracarboxylic dianhydride, BTDA), oxydiphthalic dianhydride (4,4-oxydiphthalic dianhydride, ... The compound may include at least one of 4,4'-bis(3,4-dicarboxyphenoxy)diphenyl sulfide dianhydride (ODPA), bis(3,4dicarboxyphenyl)dimethyl-silane dianhydride (SiDA), bisdicarboxyphenoxydiphenyl sulfide dianhydride (BDSDA), sulfonyldiphthalic anhydride (SO2DPA), cyclobutane-1,2,3,4-tetracarboxylic dianhydride (CBDA), and isopropylidenephenoxy bis(phthalic anhydride) (6HBDA).

[0059] More specifically, according to one embodiment of the present invention, the dianhydride compound may include at least one of biphenyltetracarboxylic dianhydride (3,3,4,4-biphenyltetracarboxylic dianhydride, BPDA), 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA), pyromellitic acid dianhydride (1,2,4,5-benzene tetracarboxylic dianhydride, PMDA), benzophenone tetracarboxylic dianhydride (3,3,4,4-benzophenone tetracarboxylic dianhydride, BTDA), oxydiphthalic dianhydride (4,4-oxydiphthalic dianhydride, ODPA), and cyclobutane-1,2,3,4-tetracarboxylic dianhydride (CBDA). However, one embodiment of the present invention is not limited thereto.

[0060] According to one embodiment of the present invention, the dicarbonyl compound may include at least one of terephthaloyl chloride (TPC), phthaloyl chloride, isophthaloyl chloride (IPC), 4,4'-biphenyldicarbonyl chloride (DPDOC), 4,4'-oxybis(benzoyl chloride) (OBBOC), naphthalene-2,3-dicarbonyl dichloride, and 1,4-cyclohexanedicabonyl dichloride (CHDOC).

[0061] More specifically, according to an embodiment of the present invention, the dicarbonyl compound may include at least one of terephthaloyl chloride (TPC), phthaloyl chloride, and isophthaloyl chloride (IPC), but the embodiment of the present invention is not limited thereto.

[0062] According to an embodiment of the present invention, the total equivalents of the dianhydride-based compound and the dicarbonyl-based compound may be substantially the same as the equivalents of the diamine-based monomer.

[0063] The polymerizable composition according to an embodiment of the present invention may contain 60 mol % or more of a dicarbonyl-based compound based on the total moles of the dianhydride-based compound and the dicarbonyl-based compound in order to ensure excellent mechanical properties.

[0064] For example, the molar ratio of the dianhydride compound to the dicarbonyl compound may be in the range of 5:95 to 40:60.

[0065] The light-transmitting matrix (110) may have a thickness sufficient to allow the optical film (100) to protect the display panel. For example, the light-transmitting matrix (110) may have a thickness of 10 to 100 μm. The thickness of the light-transmitting matrix (110) may be the same as the thickness of the optical film (100).

[0066] According to one embodiment of the present invention, the filler 120 may have a rod or fiber shape. Hereinafter, a shape that is longer than its diameter is referred to as a fiber shape. A fiber shape can also be referred to as a filament shape. According to one embodiment of the present invention, the length of the filler 120 may be more than twice its diameter.

[0067] According to one embodiment of the present invention, the filler 120 tends to be aligned along the polymer resin contained in the light-transmitting matrix 110. For example, the filler 120 may be bonded to the main chain of the polymer resin through secondary bonds such as hydrogen bonds, dipole moments, etc., and may be aligned along the main chain.

[0068] According to one embodiment of the present invention, the filler 120 has a fibrous shape and can entangle the polymer chains that make up the light-transmitting matrix 110. As a result, the stability and alignment characteristics of the polymer chains are improved, which may improve the mechanical properties of the light-transmitting matrix 110 and the optical film 100.

[0069] According to one embodiment of the present invention, the aspect ratio of the filler 120 may be in the range of 30 to 1,000. The aspect ratio is the ratio of the length to the diameter of the filler 120.

[0070] If the aspect ratio of the filler (120) is less than 30, the length of the filler (120) may be insufficient, and the function of entangling the polymer chains with each other may not be fully exerted, and the effect of improving the stability and alignment characteristics of the polymer chains may not be fully exerted.

[0071] If the aspect ratio of the filler (120) exceeds 1,000, the length of the filler (120) will be too long, reducing the dispersibility of the filler (120) and potentially causing the filler (120) to aggregate within the light-transmitting matrix (110). As a result, the light transmittance of the optical film (100) may decrease, the haze may increase, and the optical properties of the optical film (100) may be degraded. In addition, the mechanical strength of the optical film (100) may be reduced in areas where the filler (120) aggregates.

[0072] According to one embodiment of the present invention, the length of the filler 120 may be in the range of 1 to 10 μm.

[0073] If the length of the filler (120) is less than 1 μm, the filler (120) may not be able to fully entangle the polymer chains.

[0074] If the length of the filler (120) exceeds 10 μm, the dispersibility of the filler (120) may decrease. As a result, the filler (120) may aggregate within the light-transmitting matrix (110), and gelation may occur due to interaction with the polymer chains. This may result in a decrease in the light transmittance of the optical film (100), an increase in haze, and a deterioration in the optical properties of the optical film (100).

[0075] According to one embodiment of the present invention, the diameter of the filler (120) may be in the range of 3 to 330 nm.

[0076] If the diameter of the filler (120) is less than 3 nm, the stability of the filler (120) may decrease, causing the filler (120) to break or break, and may contaminate the optical film (100), increasing the haze of the optical film (100).

[0077] If the diameter of the filler (120) exceeds 330 nm, the filler (120) may not be able to maintain a fibrous shape or may have a reduced ability to entangle polymer chains with each other. In addition, the haze of the optical film (100) may increase or the light transmittance may decrease.

[0078] The type of filler 120 is not particularly limited. Any fibrous material may be used as the filler 120 according to an embodiment of the present invention. The filler 120 may be inorganic or organic. The filler 120 may include at least one of inorganic fibers, organic fibers, and organic-inorganic composite fibers.

[0079] More specifically, the filler 120 may have a fibrous shape. For example, the filler 120 may have a single fiber shape, a plurality of fibers, or a shape in which a plurality of fibers are arranged in the form of branches from a single center.

[0080] According to an embodiment of the present invention, the filler 120 may include at least one of glass fiber, aluminum-based fiber, titanium fiber, and fluoride fiber.

[0081] The glass fibers can contain SiO2. The glass fibers may further contain other components in addition to SiO2. The aluminum-based fibers can contain alumina hydrate (aluminum oxide hydroxide). The aluminum-based fibers may further contain other components in addition to alumina hydrate (aluminum oxide hydroxide). The titanium fibers can contain TiO2. The titanium fibers may further contain other components in addition to TiO2. The fluorine fibers can contain at least one of PTFE (Polytetrafluoroethylene) and PVDF (Polyvinylidene Fluoride). The fluorine fibers may further contain other components in addition to PTFE and PVDF.

[0082] According to one embodiment of the present invention, the filler 120 may include aluminum-based fibers, which may include, for example, aluminum oxide hydroxide.

[0083] According to one embodiment of the present invention, the filler 120 may include alumina hydrate. Alumina hydrate, also known as boehmite, is represented as γ-AlO(OH). More specifically, alumina hydrate may include a unit structure represented by any one of the following chemical formulas 1, 2, and 3.

[0084] [Chemical formula 1] JPEG2025540218000002.jpg66139

[0085] [Chemical formula 2] JPEG2025540218000003.jpg54139

[0086] [Chemical formula 3] JPEG2025540218000004.jpg58139

[0087] Here, n is in the range of 50 to 10,000, m is in the range of 50 to 10,000, and p is in the range of 100 to 20,000.

[0088] To help understand the structure of the filler (120), the structures of Chemical Formulas 1, 2, and 3 may be expanded to include a structure represented by any of the following Chemical Formulas 4, 5, and 6.

[0089] The structure represented by Chemical Formula 1 can be represented, for example, by the following Chemical Formula 4. The following Chemical Formula 4 corresponds to the case where n is 5 in Chemical Formula 1.

[0090] [Chemical formula 4] JPEG2025540218000005.jpg53170

[0091] The structure represented by Chemical Formula 2 can be represented, for example, by the following Chemical Formula 5. The following Chemical Formula 5 corresponds to the case where m is 4 in Chemical Formula 2.

[0092] [Chemical formula 5] JPEG2025540218000006.jpg37170

[0093] The structure represented by Chemical Formula 3 can be represented, for example, by the following Chemical Formula 6. The following Chemical Formula 6 corresponds to the case where p is 3 in Chemical Formula 3.

[0094] [Chemical formula 6] JPEG2025540218000007.jpg54170

[0095] In the above chemical formulas 4 to 6, "*" indicates a bonding position.

[0096] According to one embodiment of the present invention, SiO2 may have a unit structure represented by the following Chemical Formula 7:

[0097] [Chemical formula 7] JPEG2025540218000008.jpg83170

[0098] According to one embodiment of the present invention, the filler 120 may be surface-treated. For example, fibers surface-treated with an organic compound having an alkoxy group may be used as the filler 120.

[0099] According to one embodiment of the present invention, when a filler 120 is added, the filler 120 causes appropriate light scattering, thereby improving the optical properties of the optical film 100. To enhance the light scattering effect, the content of the filler 120 contained in the optical film 100 may be adjusted.

[0100] According to one embodiment of the present invention, the content of the filler (120) may be in the range of 3 to 50 wt % based on the total weight of the optical film (100). More specifically, the content of the filler (120) based on the total weight of the optical film (100) may be adjusted to 4 to 30 wt %, or may be 5 to 20 wt %.

[0101] If the content of the filler (120) is less than 3% by weight of the total weight of the optical film (100), the light scattering effect of the filler (120) may be weak, and the effect of improving the light transmittance of the optical film (100) may be almost insignificant, and the filler (120) may not fully function to intertwine the polymer chains with each other.

[0102] On the other hand, if the content of the filler (120) exceeds 50% by weight of the total weight of the optical film (100), the dispersibility of the filler (120) may decrease, the haze of the optical film (100) may decrease, and the excessive amount of filler (120) may cause the filler (120) to aggregate, which may block light and reduce the light transmittance of the optical film (100).

[0103] The true density of the optical film (100) according to an embodiment of the present invention is 1.55 to 1.67 g / cm 3 It is possible.

[0104] The true density refers to the density of the solid of the optical film 100 excluding voids. In the case of small materials, the true density refers to the density of only the portion completely filled with material, excluding the gaps between particles. According to one embodiment of the present invention, the true density refers to the density of only the portion filled with the light-transmitting matrix 110 and filler 120, excluding voids. The true density of the optical film 100 can be measured, for example, using an Accupyc II 1340 pycnometer.

[0105] When the filler (120) according to one embodiment of the present invention has a fibrous shape, it can have a higher true density than a spherical filler of the same weight. For example, the true density of the optical film (100) when 20% of the total weight of the fibrous filler (120) is added is the same as the true density of the optical film (100) when 40% of the total weight of the spherical filler is added. Therefore, the use of the fibrous filler (120) may be advantageous not only in terms of mechanical properties but also in terms of optical properties.

[0106] FIG. 2 is a cross-sectional view of a part of a display device 200 according to another embodiment of the present invention, and FIG. 3 is an enlarged cross-sectional view of part "P" in FIG.

[0107] Referring to FIG. 2, a display device (200) according to another embodiment of the present invention includes a display panel (501) and an optical film (100) on the display panel (501).

[0108] 2 and 3, the display panel 501 includes a substrate 510, a thin film transistor (TFT) on the substrate 510, and an organic light emitting element 570 connected to the thin film transistor (TFT). The organic light emitting element 570 includes a first electrode 571, an organic light emitting layer 572 on the first electrode 571, and a second electrode 573 on the organic light emitting layer 572. The display device 200 shown in FIGS. 2 and 3 is, for example, an organic light emitting display device.

[0109] The substrate 510 may be made of glass or plastic. Specifically, the substrate 510 may be made of plastic, such as a polyimide resin or an optical film. Although not shown, a buffer layer may be disposed on the substrate 510.

[0110] The thin film transistor (TFT) is disposed on the substrate 510. The thin film transistor (TFT) includes a semiconductor layer 520, a gate electrode 530 insulated from the semiconductor layer 520 and overlapping at least a portion of the semiconductor layer 520, a source electrode 541 connected to the semiconductor layer 520, and a drain electrode 542 spaced apart from the source electrode 541 and connected to the semiconductor layer 520.

[0111] 3, a gate insulating film 535 is disposed between the gate electrode 530 and the semiconductor layer 520. An interlayer insulating film 551 may be disposed on the gate electrode 530, and a source electrode 541 and a drain electrode 542 may be disposed on the interlayer insulating film 551.

[0112] The planarization film (552) is disposed on the thin film transistor (TFT) and flattens the top of the thin film transistor (TFT).

[0113] The first electrode 571 is disposed on the planarization layer 552. The first electrode 571 is connected to the thin film transistor (TFT) through a contact hole formed in the planarization layer 552.

[0114] The bank layer 580 is disposed on a portion of the first electrode 571 and the planarization film 552, and defines a pixel region or a light-emitting region. For example, the bank layer 580 may be disposed in a matrix structure in the boundary region between a plurality of pixels, thereby defining the pixel region.

[0115] The organic light-emitting layer 572 is disposed on the first electrode 571. The organic light-emitting layer 572 may also be disposed on the bank layer 580. The organic light-emitting layer 572 may include one light-emitting layer or two light-emitting layers stacked one above the other. The organic light-emitting layer 572 may emit light of at least one color selected from red, green, and blue, or may emit white light.

[0116] A second electrode (573) is disposed on the organic light-emitting layer (572).

[0117] The first electrode 571, the organic light emitting layer 572, and the second electrode 573 may be stacked to form the organic light emitting element 270.

[0118] Although not shown, when the organic light emitting layer 572 emits white light, each pixel may include a color filter for filtering the white light emitted from the organic light emitting layer 572 by wavelength. The color filter is formed on the path of light.

[0119] A thin film encapsulation layer (590) may be disposed on the second electrode (573). The thin film encapsulation layer (590) may include at least one organic film and at least one inorganic film, and the at least one organic film and the at least one inorganic film may be alternately disposed.

[0120] An optical film 100 is disposed on the display panel 501 having the above-described laminated structure. The optical film 100 includes a light-transmitting matrix 110 and a filler 120 dispersed in the light-transmitting matrix 110.

[0121] The optical film 100 according to an embodiment of the present invention may have a hardness (HM) of 220 MPa or more based on a thickness of 50 μm. The HM is the Martens hardness of the optical film 100 according to an embodiment of the present invention. The Martens hardness is defined in units of MPa.

[0122] The Martens hardness of the optical film (100) according to one embodiment of the present invention is measured by measuring the surface hardness of the mark made by pressing the light-transmitting matrix (110) with a diamond pyramid, where the pressing load is A kg and the surface area is B mm 2 Then, after calculating HM=A / B, the value can be converted to MPa. The Martens hardness can be measured under the following conditions: 12mN / Running Time 12s / Hold Time 5s.

[0123] The Martens hardness of the optical film (100) can be measured using, for example, a Fisher HM-2000 as a Martens hardness measuring device.

[0124] The optical film (100) according to an embodiment of the present invention may have an HM in the range of 220 to 300 MPa. More specifically, the optical film (100) may have an HM in the range of 240 to 280 MPa.

[0125] If the HM of the optical film 100 is less than 220 MPa, it may be vulnerable to external pressure, for example, scratches or cracks may easily occur when external force is applied to the optical film 100.

[0126] The optical film 100 according to an embodiment of the present invention may have a HV of 46 or more based on a thickness of 50 μm, where HV is the Vickers hardness of the optical film 100 according to an embodiment of the present invention.

[0127] The Vickers hardness of the optical film (100) according to an embodiment of the present invention was measured by pressing a diamond pyramid against the light-transmitting matrix (110) and measuring the surface hardness of the pressing mark, where the pressing load was C kg and the surface area was D mm 2 Then, the calculation is HV = C / D. Vickers hardness can be measured under the following conditions: 12mN / Running Time 12s / Hold Time 5s.

[0128] The Vickers hardness of the optical film (100) can be measured using, for example, a Fisher HM-2000 as a Vickers hardness measuring device.

[0129] If the HV of the optical film 100 is less than 46, it may be vulnerable to external pressure. For example, if an external force is applied to the outside of the optical film 100, scratches or cracks may easily occur.

[0130] The optical film 100 according to an embodiment of the present invention may have a 1 mm dent strength of 10.7 N or more based on a 50 μm thickness. The basic unit of 1 mm dent strength is defined as N.

[0131] The 1 mm dent strength can be defined as the resistance of the optical film (100) to the pressure when the optical film (100) is pressed vertically to a depth of 1 mm from the point where a force of 1 N is applied.

[0132] The 1 mm dent strength is an index showing the surface hardness of the optical film 100, and excellent 1 mm dent strength means high resistance to external forces.

[0133] The 1 mm dent strength can be measured, for example, as follows. First, a 60 mm x 60 mm sample of the optical film 100 according to one embodiment of the present invention is fabricated. The fabricated optical film 100 sample is placed on a fixture with a circular opening in the center, and then secured with a clamp. A probe with a cylindrical head having a diameter of 1.59 mm attached to a universal testing machine presses the optical film 100 sample vertically at a speed of 5 mm / min. The point where a force of 1 N is applied to the probe is set as the reference point. The force measured when the probe presses the optical film 100 to a depth of 1 mm from the reference point is the 1 mm dent strength of the optical film 100. For example, an Instron universal testing machine, a fixed fixture (S1-11855), a clamp, and a probe (2830-005) can be used to measure the 1 mm dent strength.

[0134] If the 1 mm dent strength of the optical film (100) is less than 10.7 N, for example, when the optical film (100) is used as a cover window of a display device, external forces generated by a touch pen, fingernail, foreign object, etc. may cause pressure marks, scratches, etc. on the cover window, which may lead to a deterioration in the appearance quality of the cover window.

[0135] The optical film 100 according to an embodiment of the present invention may have a recovery rate (nIT) of 60 to 100%, and the basic unit of the recovery rate is defined as percent (%).

[0136] The recovery rate of the optical film 100 can be measured by, for example, using a nanoindenter, applying a 12 mN load to the optical film 100 for 12 seconds at a temperature of 24°C and a humidity of 40 RH%, waiting for 5 seconds at the point of maximum compression, and then removing the applied load (12 mN / 12 s / Creep 5 s / 24°C, 40 RH), and measuring the degree to which the optical film 100 recovers from the compression. Fischer's HM2000 model can be used as the nanoindenter.

[0137] If the recovery rate of the optical film (100) is less than 60%, the recovery force of the optical film (100) when folded or unfolded may be insufficient, and fold or pressing marks may remain, which may make it difficult to apply to a foldable or rollable display.

[0138] A method for manufacturing an optical film 100 according to an embodiment of the present invention will now be described.

[0139] According to one embodiment of the present invention, a method for manufacturing an optical film 100 may include the steps of preparing a polyimide resin powder, preparing a polyimide resin solution using the polyimide resin powder, preparing a filler dispersion, mixing the filler dispersion and the polyimide resin solution to prepare a filler resin mixture in which a filler 120 is dispersed, and manufacturing an optical film 100 using the prepared filler resin mixture. Each step will be described in detail below.

[0140] According to one embodiment of the present invention, a polyimide resin solution can be used as the resin solution for forming the light-transmitting matrix 110.

[0141] According to one embodiment of the present invention, a method for manufacturing the optical film 100 may include the step of preparing a polyimide-based resin powder.

[0142] More specifically, according to an embodiment of the present invention, the step of preparing a polyimide-based resin powder may include the steps of: forming a first reaction solution using a diamine-based monomer and a dianhydride-based compound; adding a dicarbonyl-based compound to the first reaction solution and reacting them to form a second reaction solution; adding a dehydrating agent and an imidization catalyst to the second reaction solution and reacting them to form a third reaction solution; and treating the third reaction solution to prepare a solid polymer resin.

[0143] To prepare the polyimide resin powder, first, a first reaction solution is formed using a diamine monomer and a dianhydride compound.

[0144] Examples of the first solvent used to prepare the first reaction solution include aprotic solvents such as N,N-dimethyl acetamide (DMAc), N,N-dimethyl formamide (DMF), 1-methyl-2-pyrrolidinone (NMP), m-cresol, tetrahydrofuran (THF), chloroform, and methyl ethyl ketone (MEK), as well as mixtures thereof. However, the first solvent according to an embodiment of the present invention is not limited thereto, and other solvents may be used as the first solvent.

[0145] The specific types of diamine-based monomers and dianhydride-based compounds have already been described, so the overlapping description will be omitted.

[0146] According to one embodiment of the present invention, the first reaction solution may include polyamic acid and polyimide repeating units.

[0147] Next, a dicarbonyl compound is added to the first reaction solution and reacted to form a second reaction solution. For example, the dicarbonyl compound may be added to the first reaction solution 1 to 24 hours after the formation of the first reaction solution. More specifically, the dicarbonyl compound may be added to the first reaction solution 1 to 20 hours after the formation of the first reaction solution.

[0148] According to one embodiment of the present invention, when the dicarbonyl compound starts to be added to the first reaction solution, the reaction solution becomes the second reaction solution.

[0149] The specific types of dicarbonyl compounds have already been described, so the overlapping details will be omitted.

[0150] According to an embodiment of the present invention, the total equivalents of the dianhydride-based compound and the dicarbonyl-based compound may be substantially the same as the total equivalents of the diamine-based monomer.

[0151] According to an embodiment of the present invention, the molar ratio of the dianhydride compound to the dicarbonyl compound may be in the range of 5:95 to 40:60.

[0152] Next, a dehydrating agent and an imidization catalyst are added to the second reaction liquid and reacted to form a third reaction liquid.

[0153] According to one embodiment of the present invention, a dehydrating agent and an imidization catalyst are added to the second reaction solution, which is then refluxed and stirred at a temperature of 60°C to 80°C for 30 minutes to 2 hours, resulting in the formation of a third reaction solution.

[0154] As the dehydrating agent, an acid anhydride such as acetic anhydride, propionic anhydride, isobutyric anhydride, pivalic anhydride, butyric anhydride, or isovaleric anhydride may be used.

[0155] As the imidization catalyst, a tertiary amine such as isoquinoline, β-picoline, or pyridine may be used.

[0156] The third reaction liquid is then treated to produce a solid state polymeric resin.

[0157] To produce a solid polymer resin, a second solvent may be added to the third reaction solution. Examples of the second solvent include ethanol, methanol, hexane, and distilled water. The second solvent may be used alone or in combination of two or more solvents.

[0158] When a solvent that is well mixed with the first solvent but has low solubility in the polymer resin is added to the third reaction solution as the second solvent, a powdery solid polymer resin precipitates. The precipitate is filtered and dried to obtain a high-purity solid polymer resin. When the liquid components are removed during the filtering process, unreacted monomers, oligomers, additives, and reaction by-products are also removed.

[0159] The polymer resin thus obtained may be in the form of a solid powder and may contain imide repeating units and amide repeating units. The polymer resin may be a polyimide-based resin, such as a polyamideimide-based resin. The polymer resin may also be referred to as a polymerizable composition.

[0160] According to an embodiment of the present invention, a method for manufacturing the optical film 100 may include preparing a polyimide resin solution using a polyimide resin powder.

[0161] To prepare a polyimide resin solution using the polyimide resin powder, the polyimide resin powder may be dissolved in a third solvent. The third solvent may be N,N-dimethyl acetamide (DMAc). However, the present invention is not limited thereto, and other well-known solvents may be used as the third solvent.

[0162] According to one embodiment of the present invention, a method for manufacturing an optical film 100 may include preparing a filler dispersion.

[0163] Fibrous fillers 120, for example, fibrous fillers 120 with a high aspect ratio, are long compared to their diameter and are prone to entanglement or aggregation within the optically transparent matrix 110. Therefore, the fillers 120 require excellent dispersibility within the filler-resin mixture.

[0164] The filler dispersion may be prepared by dispersing the filler 120 in a fourth solvent. The fourth solvent may be at least one of N,N-dimethyl acetamide (DMAc) or methyl ethyl ketone (MEK). However, the present invention is not limited thereto, and other well-known solvents may be used as the fourth solvent.

[0165] According to one embodiment of the present invention, in order to ensure that the filler 120 has good dispersibility in the filler resin mixture, a filler dispersion may be prepared and mixed separately from the polyimide resin solution.

[0166] More specifically, the filler dispersion may contain, for example, 75 to 85 wt % of DMAc (N,N-dimethyl acetamide), 5 to 10 wt % of acetic acid, 2 to 7 wt % of p-toluenesulfonic acid (PTSA), and 10 wt % of filler (120) relative to the total weight of the filler dispersion.

[0167] In the filler dispersion, p-toluenesulfonic acid (PTSA) can be used as an additive to improve the dispersibility of the filler 120. However, one embodiment of the present invention is not limited thereto, and other well-known additives may be used to improve the dispersibility of the filler 120.

[0168] In the filler dispersion, acetic acid can be used as a pH adjuster to prevent the filler 120 from flocculating or entangling and improve dispersion stability. However, one embodiment of the present invention is not limited thereto, and other well-known acetic acids may be used to prevent the filler 120 from flocculating or entangling and improve dispersion stability.

[0169] According to one embodiment of the present invention, the content of the filler 120 in the optical film 100 can be adjusted by the amount of filler dispersion mixed when mixing the polyimide resin solution with the filler dispersion.

[0170] According to an embodiment of the present invention, a method for manufacturing the optical film 100 may include manufacturing the optical film 100 using the prepared filler resin mixture.

[0171] According to one embodiment of the present invention, after preparing a filler resin mixture by mixing a filler dispersion and a polyimide resin solution, the pH of the filler resin mixture may be adjusted to improve the dispersibility of the filler (120) mixed in the filler resin mixture. For example, the pH of the filler resin mixture may be adjusted to a range of 4 to 7. This prevents the filler (120) from agglomerating or entangling.

[0172] The filler resin mixture is then cast, dried, and heat-treated to form the optical film 100. According to one embodiment of the present invention, a film formed by casting the filler resin mixture is called a cast film, and a film produced by drying and heat-treating the cast film is called the optical film 100. The cast film can also be called an uncured film.

[0173] In addition, convection can be prevented during the drying and heat treatment of the cast film formed by casting, and the filler 120 can be oriented in a certain direction.

[0174] Specifically, when drying a cast film using heat, if convection occurs inside, the orientation of the filler (120) may be reduced. Therefore, to prevent convection, the cast film can be dried slowly. For example, the cast film is dried while increasing the temperature from 80°C to 120°C at a rate of 1°C / minute (1 degree / minute). When the film is dried to a certain level, the orientation of the filler (120) can be fixed.

[0175] By the above manufacturing method, the optical film 100 according to one embodiment of the present invention can be manufactured.

[0176] The present invention will be described in more detail below with reference to illustrative manufacturing examples and examples, but the present invention is not limited to the manufacturing examples and examples described below.

[0177] <Production example: Production of polyimide polymer solids> A 1 L reactor equipped with a stirrer, nitrogen injector, loading funnel, temperature controller, and condenser was charged with 701.979 g of N,N-dimethyl acetamide (DMAc) while passing nitrogen through it. The temperature of the reactor was then raised to 25°C, and 54.439 g (0.17 mol) of bistrifluoromethylbenzidine (TFDB) was dissolved in the solution, which was then maintained at 25°C. 5.668 g (0.029 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBDA) was added and stirred for 3 hours until the CBDA was completely dissolved. Then, 12.839 g (0.029 mol) of 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) was added and completely dissolved. The temperature of the reactor was lowered to 10°C, and 22.779 g (0.112 mol) of terephthaloyl chloride (TPC) was added, followed by reaction at 25°C for 12 hours to obtain a polymer solution with a solid concentration of 12 wt%.

[0178] 10.06 g of pyridine and 12.99 g of acetic anhydride were added to the resulting polymer solution and stirred for 30 minutes. The temperature was then raised to 80°C, and the mixture was stirred at the same temperature for 1 hour to allow the reaction to proceed. After cooling to room temperature, 20 L of methanol was added to the resulting polymer solution to precipitate the solids. The precipitated solids were filtered and pulverized, washed with 2 L of methanol, and dried at 100°C in a vacuum for at least 6 hours to obtain a powdered polyimide-based polymer solid. The polyimide-based polymer solid produced here is a polyamide-imide polymer solid. This is also referred to as a polymerizable composition.

[0179] Example 1 723.46 g of DMAc (first solvent) was placed in a 1 L reactor and stirred for a certain period of time while maintaining the temperature of the reactor at 10° C. Then, 110 g of solid powder polyamideimide (polyimide resin powder) prepared according to Preparation Example was added and stirred for 1 hour, and the temperature was raised to 25° C. to prepare a liquid polyimide resin solution.

[0180] A filler dispersion was prepared separately from the polyimide resin solution, and this filler dispersion was a dispersion of alumina hydrate fibers.

[0181] More specifically, a filler dispersion was prepared containing 80 wt % of DMAc (N,N-dimethylacetamide, second solution), 5 wt % of acetic acid, 5 wt % of p-toluenesulfonic acid (PTSA), and 10 wt % of filler (120) relative to the total weight of the filler dispersion. Here, alumina hydrate fibers with an average diameter of 4 nm and an average length of 1,500 nm were used as the filler (120).

[0182] 55 g of the prepared filler dispersion was slowly added to the prepared liquid polyimide resin solution over a period of 1 hour using a cylinder pump to prepare a filler resin mixture in which the filler dispersion and the polyimide resin solution were mixed. The filler dispersion was used so that the content of the filler (120) was 10 wt % based on the total weight of the solids (polyimide resin component + filler).

[0183] Immediately after preparing the filler resin mixture, the pH of the filler resin mixture was measured and found to be above pH 7. In order to improve the dispersion and alignment of the filler (120), a weak acid such as acetic acid was added to the filler resin mixture to adjust the pH of the filler resin mixture to a range of 4 to 7, specifically pH 6.5. The filler resin mixture prepared in this manner is a polyimide resin solution in which the fibrous filler (120) is dispersed.

[0184] The obtained filler resin mixture was cast. A cast substrate was used for casting. The type of the cast substrate is not particularly limited. The cast substrate may be a glass substrate, a stainless steel (SUS) substrate, a Teflon (registered trademark) substrate, or the like. According to one embodiment of the present invention, a glass substrate may be used as the cast substrate.

[0185] Specifically, the obtained filler resin mixture was applied to a glass substrate and cast. In order to improve the orientation of the filler (120), the filler resin mixture was applied to the glass substrate (cast substrate), and then cast while applying a force of 30 N in a direction perpendicular to the glass substrate. As a result, a cast film was produced.

[0186] During the drying process of the cast film, in order to maintain the orientation of the filler (120), it was placed in a hot air oven at 80°C and slowly dried at a rate of 1°C / min up to 120°C for 40 minutes to produce a film, which was then peeled off from the glass substrate and fixed to a frame with pins.

[0187] The frame with the film fixed thereto was placed in a vacuum oven and slowly heated from 100°C to 280°C for 2 hours, and then slowly cooled. It was then separated from the frame to obtain the optical film 100. The obtained optical film 100 was then heat-treated again at 250°C for 5 minutes.

[0188] As a result, an optical film (100) having a thickness of 50 μm was obtained, which contained a light-transmitting matrix (110) and a filler (120) dispersed in the light-transmitting matrix (110).

[0189] <Examples 2 and 3> According to the conditions in Table 1, optical films (100) were prepared in the same manner as in Example 1 except for the content of the filler (120) and the pH of the first mixed solution, and these were designated as Examples 2 and 3, respectively.

[0190] <Comparative Example 1> An optical film (100) was produced in the same manner as in Example 1 under the conditions in Table 1, except that the filler (120) was not added and the pH of the first mixed solution was changed. This was designated Comparative Example 1.

[0191] <Comparative Examples 2 to 5> According to the conditions in Table 1, optical films (100) were produced in the same manner as in Example 1, except for the type and content of the filler (120) and the pH of the first mixed solution, and these were designated as Comparative Examples 2 to 5, respectively.

[0192] [Table 1]

[0193] In Table 1, Filler 1 is an alumina hydrate fiber filler with a diameter (A) of 4 nm, a length (B) of 1,500 nm, and a B / A ratio of 375, and Filler 2 is spherical nanoparticles with a particle size of 15 nm.

[0194] In Table 1, the molar ratios indicate relative molar ratios based on 100 moles of the total diamines.

[0195] In Table 1, "wt %" means the weight % of the filler relative to the total weight of the optical film.

[0196] <Measurement of physical properties> The optical films having a thickness of 50 μm produced in Examples 1 to 3 and Comparative Examples 1 to 5 were measured for the following physical properties.

[0197] (1) Measurement of true density Using the optical films manufactured in Examples 1 to 3 and Comparative Examples 1 to 5, 10 x 10 cm 2 The optical film sample (10 x 10 cm) was manufactured. 2 1 x 1cm 2 The optical film was cut into small pieces to the following size and placed in a sample holder with an iron ball (crusher). A cryo-crusher (Japan Analytical Industry Co., Ltd., JFC-300) was filled with liquid nitrogen to more than two-thirds, and the sample holder containing the cut optical film sample was connected to the cryo-crusher. The chamber was then closed, and the specimen was crushed using the cryo-crusher for 15 minutes or more per run (pre-cooling). The true density of the crushed optical film sample was measured seven times using a Micromeritics Accu Pyc 1340 Pycnometer (using helium gas). The highest and lowest true density values ​​were excluded, and the average of the remaining true density values ​​was calculated to determine the true density of the optical film.

[0198] (2) Measurement of Martens hardness (HM) The optical films produced in Examples 1 to 3 and Comparative Examples 1 to 5 were pressed with a diamond pyramid with a diagonal of 90 degrees according to the method of ISO 14577-1, and the surface hardness of the pressed mark was measured. The pressing load was A kg, and the surface area was B mm. 2 Then, the Martens hardness of the optical film was calculated by HM = A / B, and the value was converted to MPa. The Martens hardness was measured using a Fisher HM-2000 measuring device.

[0199] - Force: 12mN - Running Time: 12 seconds - Hold Time: 5 seconds

[0200] (3) Vickers hardness (HV) measurement The optical films produced in Examples 1 to 3 and Comparative Examples 1 to 5 were pressed down with a diamond pyramid with a diagonal of 136 degrees according to the method of ISO 14577-1, and the surface hardness of the pressed down mark was measured. The pressing load was C kg, and the surface area was D mm. 2 Then, the Vickers hardness of the optical film was calculated using HV = C / D. The Vickers hardness was measured using a Fisher HM-2000 measuring device.

[0201] - Force: 12mN - Running Time: 12 seconds - Hold Time: 5 seconds

[0202] (4) Measurement of 1mm dent strength Optical film samples measuring 60 mm x 60 mm were prepared from the optical films prepared in Examples 1 to 3 and Comparative Examples 1 to 5. The prepared optical film samples were placed on a fixture with a circular opening in the center and then secured in place with clamps. A probe with a cylindrical head and a diameter of 1.59 mm attached to a universal testing machine was then pressed vertically from the surface of the optical film sample at a speed of 5 mm / min. The point where a force of 1 N was applied to the probe was defined as the reference point. The force applied to the probe when the probe pressed into the optical film sample to a depth of 1 mm from the reference point was measured as the 1 mm dent strength.

[0203] (5) Measurement of recovery rate (nIT) The recovery rates of the optical films manufactured in Examples 1 to 3 and Comparative Examples 1 to 5 were measured by applying a load of 12 mN to the optical film (100) for 12 seconds at a temperature of 24°C and a humidity of 40 RH% using a Fischer HM2000 nanoindenter, waiting for 5 seconds at the point where the optical film was most compressed, and then removing the applied load (conditions: 12 mN / 12 s / Creep 5 s / 24°C, 40 RH%).

[0204] The measurement results are shown in Table 2 below.

[0205] [Table 2]

[0206] As shown in the measurement results in Table 2, the optical film (100) according to the embodiment of the present invention exhibits excellent surface properties, with HM of 225 MPa or more and HV of 46 or more. In addition, the 1 mm dent strength is 10.7 N or more, demonstrating excellent dent resistance. [Explanation of symbols]

[0207] 100: Optical film 110: Light-transmitting matrix 120: Filler 200:Display device 501: Display panel

Claims

1. a light-transmitting matrix; and a filler dispersed in the optically transparent matrix; Optical film with a 1mm dent strength of 10.7N or more based on a thickness of 50μm: The 1 mm dent strength refers to the force that the optical film resists when pressed 1 mm when the probe is pressed vertically on the optical film at a speed of 5 mm / min using a universal testing machine equipped with a probe.

2. The optical film according to claim 1 , wherein the filler has a rod-like or fibrous shape.

3. The optical film according to claim 2 , wherein the filler has a length of 1 to 10 μm.

4. The optical film of claim 2 , wherein the filler has a diameter of 3 to 330 nm.

5. 3. The optical film of claim 2, wherein the filler has an aspect ratio of 30 to 1000. The aspect ratio is the ratio of the length to the diameter of the filler.

6. The optical film according to claim 1 , wherein the filler comprises at least one of glass fiber, aluminum-based fiber, titanium fiber, and fluoride fiber.

7. The optical film of claim 1 , wherein the filler comprises aluminum oxide hydroxide.

8. 2. The optical film according to claim 1, wherein the content of the filler is 3 to 50 wt % based on the total weight of the optical film.

9. 1.55 to 1.67 g / cm 3 The optical film of claim 1 having a true density of

10. The optical film of claim 1, having an HM of 220 MPa or more based on a thickness of 50 μm: HM is the Martens hardness of the optical film, The HM is measured using an HM-2000 under the conditions of 12 mN / running time 12 seconds / hold time 5 seconds.

11. 10. The optical film of claim 1, having an HV of 46 or more based on a thickness of 50 μm: HV is the Vickers hardness of the optical film, The HV is measured using HM-2000 under the conditions of 12 mN / running time 12 seconds / hold time 5 seconds.

12. 10. The optical film of claim 1, having a recovery rate (nIT) of 60 to 100%: Here, the recovery rate is measured using a nanoindenter under the conditions of 12 mN / 12 seconds (12 s) / Creep 5 seconds (Creep 5 s) / 24° C., 40 RH%.

13. 10. The optical film of claim 1, wherein the light-transmitting matrix comprises at least one of an imide repeat unit and an amide repeat unit.

14. 2. The optical film according to claim 1, wherein the light-transmitting matrix is ​​formed from a polymerizable composition including: a diamine-based monomer; and at least one of a dianhydride-based compound and a dicarbonyl-based compound.

15. The diamine monomers include bistrifluoromethylbenzidine (2,2'-bis(trifluoromethyl)benzidine, TFDB), oxydianiline (4,4'-oxydianiline, ODA), p-phenylenediamine (para-phenylene diamine, pPDA), m-phenylenediamine (meta-phenylene diamine, mPDA), p-methylenediamine (para-Methylene Diamine, pMDA), m-methylenediamine (meta-Methylene Diamine, mMDA), bisaminophenoxybenzene (1,3-bis(3-aminophenoxy)benzene, 133APB), bisaminophenoxybenzene (1,3-bis(4-aminophenoxy)benzene, 134APB), bisaminophenoxyphenyl hexafluoropropane (2,2'-bis[4(4-aminophenoxy)phenyl] hexafluoropropane (4BDAF), bisaminophenyl hexafluoropropane (2,2'-bis(3-aminophenyl)hexafluoropropane (33-6F), bisaminophenyl hexafluoropropane (2,2'-bis(4-aminophenyl)hexafluoropropane (44-6F), bisaminophenyl sulfone (bis(4-aminophenyl)sulfone (4DDS), bisaminophenyl sulfone (bis(3-aminophenyl)sulfone (3DDS), cyclo Hexanediamine (1,3-Cyclohexanediamine, 13CHD), cyclohexanediamine (1,4-Cyclohexanediamine, 14CHD), bisaminophenoxyphenylpropane (2,2-Bis[4-(4-aminophenoxy)-phenyl]propane, 6HMDA), bisaminohydroxyphenylhexafluoropropane (2,2-Bis(3-amino-4-hydroxyphenyl)-hexafluoropropane, DBOH), and bisaminophenoxydiphenylsulfone (4,15. The optical film according to claim 14, comprising at least one of 4'-Bis(3-amino phenoxy)diphenyl sulfone (DBSDA).

16. The dianhydride compounds include biphenyltetracarboxylic dianhydride (3,3,4,4-biphenyltetracarboxylic dianhydride, BPDA), 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA), 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic anhydride (TDA), pyromellitic acid dianhydride (1,2,4,5-benzene tetracarboxylic dianhydride, PMDA), benzophenone tetracarboxylic dianhydride (3,3,4,4-benzophenone tetracarboxylic dianhydride, BTDA), oxydiphthalic dianhydride (4,4-oxydiphthalic dianhydride, ...

15. The optical film of claim 14, comprising at least one of 4,4'-bis(3,4-dicarboxyphenoxy)diphenyl sulfide dianhydride (ODPA), bis(3,4-dicarboxyphenyl)dimethyl-silane dianhydride (SiDA), 4,4-bis(3,4-dicarboxyphenoxy)diphenyl sulfide dianhydride (BDSDA), sulfonyldiphthalic anhydride (SO2DPA), cyclobutane-1,2,3,4-tetracarboxylic dianhydride (CBDA), and 4,4'-(4,4'-Isopropylidenediphenoxy) bis(phthalic anhydride) (6HBDA).

17. 15. The optical film of claim 14, wherein the dicarbonyl compound includes at least one of terephthaloyl chloride (TPC), phthaloyl chloride, isophthaloyl chloride (IPC), 4,4'-biphenyldicarbonyl chloride (DPDOC), 4,4'-oxybis(benzoyl chloride) (OBBOC), naphthalene-2,3-dicarbonyl dichloride, and 1,4-cyclohexanedicabonyl dichloride (CHDOC).

18. 15. The optical film according to claim 14, wherein the molar ratio of the dianhydride compound to the dicarbonyl compound is in the range of 5:95 to 40:

60.

19. a display panel; and A display device comprising the optical film of any one of claims 1 to 18 disposed on the display panel.

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