Optical film and display device comprising same

Abstract

An embodiment of the present invention provides an optical film including a light-transmitting substrate, wherein the light-transmitting substrate includes: a polymer resin; a fiber-shaped filler; and a non-nitrogen-based ultraviolet absorber, wherein the optical film has a yellow index (Y.I.) of 4.0 or less before a light resistance test and a yellow index change (Y.I.) of 4.5 or less after the light resistance test. The light resistance test is performed for 300 hours by using a xenon lamp under the conditions of a daylight filter, 12 kW 0.8 W / m2 at 420 nm, 30 ℃ / 30RH% chamber, and 55 ℃ black panel. In addition, provided is a display device comprising the optical film.

Description

Optical film and display device including the same

[0001] The present invention relates to an optical film and a display device including the same.

[0002] Recently, with the trend toward thinner, lighter, and more flexible display devices, the use of optical films instead of glass as cover windows is being considered. For optical films to be used as display cover windows, they must possess both excellent optical and mechanical properties. For example, optical films must possess excellent strength, hardness, wear resistance, and flexibility.

[0003] Fillers and additives are sometimes used to impart desired properties to optical films, which require a variety of physical properties. The fillers and additives used can vary depending on the properties required for the optical film.

[0004] For example, if an optical film contains a filler, the mechanical properties of the optical film can be improved due to the dispersibility of the filler. Furthermore, if the optical film contains a UV absorber, the optical properties of the optical film can be improved, such as by minimizing color changes when exposed to light.

[0005] Meanwhile, when applying a filler dispersion and a UV absorber simultaneously, there is a problem in that the yellowness increases by more than twice compared to when only the UV absorber is applied.

[0006] Therefore, research is continuously being conducted to minimize the problem of increased yellowness even when applying filler dispersion and UV absorber simultaneously.

[0007] One embodiment of the present invention is to provide an optical film having excellent yellowness and light resistance.

[0008] One embodiment of the present invention is to provide an optical film having excellent mechanical properties as well as excellent yellowness and light resistance.

[0009] Another embodiment of the present invention is to provide a display device including an optical film having excellent yellowness and light resistance.

[0010] One embodiment of the present invention provides an optical film comprising a light-transmitting substrate, wherein the light-transmitting substrate comprises a polymer resin, a filler having a fiber shape, and a non-nitrogen-based ultraviolet absorber, and wherein the optical film has a yellowness index (YI) of 4.0 or less before a light fastness test and a yellowness change (YI) of 4.5 or less after the light fastness test. The light fastness test is performed for 300 hours using a xenon lamp under conditions of a daylight filter, 12kW 0.8W / ㎡ @420nm, 30℃ / 30RH% Chamber, and 55℃ Black Panel.

[0011] Another embodiment of the present invention provides a display device including a display panel and the optical film disposed on the display panel.

[0012] According to one embodiment of the present invention, an optical film having excellent mechanical properties and excellent light resistance can be provided.

[0013] According to another embodiment of the present invention, a display device including an optical film having excellent mechanical properties and excellent light resistance can be provided.

[0014] Figure 1 is a cross-sectional view of an optical film (100) according to one embodiment of the present invention.

[0015] Figure 2 is a cross-sectional view of an optical film (101) further including a primer layer (120).

[0016] Figure 3 is a cross-sectional view of an optical film (102) further including a hard coating layer (130).

[0017] FIG. 4 is a cross-sectional view of a portion of a display device (200) according to another embodiment of the present invention.

[0018] Figure 5 is an enlarged cross-sectional view of portion “P” of Figure 4.

[0019] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. However, the embodiments described below are presented for illustrative purposes only to facilitate a clear understanding of the present invention and do not limit the scope of the present invention.

[0020] The shapes, sizes, ratios, angles, numbers, etc. disclosed in the drawings for explaining embodiments of the present invention are merely illustrative, and the present invention is not limited to the details depicted in the drawings. Throughout the specification, identical components may be designated by identical reference numerals. In describing the present invention, detailed descriptions of related known technologies will be omitted if they are deemed to unnecessarily obscure the gist of the present invention.

[0021] In this specification, where "includes," "has," and "consists of" are used, other parts may be added, unless the expression "only" is used. When a component is expressed in the singular, the plural is included unless otherwise explicitly stated. Furthermore, when interpreting a component, it is interpreted to include a margin of error even if there is no explicit indication otherwise.

[0022] When describing a positional relationship, for example, when the positional relationship between two parts is described as 'on top of', 'upper part of', 'lower part of', 'next to', etc., one or more other parts may be located between the two parts, unless the expression 'right' or 'directly' is used.

[0023] Spatially relative terms such as "below," "beneath," "lower," "above," and "upper" can be used to easily describe the relationship of one element or component to another, as illustrated in the drawings. Spatially relative terms should be understood to include different orientations of the elements during use or operation in addition to the orientations depicted in the drawings. For example, if an element depicted in the drawings were flipped over, an element described as "below" or "beneath" another element could instead be positioned "above" the other element. Thus, the exemplary term "below" can encompass both the above and below directions. Similarly, the exemplary term "above" or "above" can encompass both the above and below directions.

[0024] When describing a temporal relationship, for example, when the temporal relationship is described as 'after', 'following', 'next to', 'before', etc., it can also include cases where it is not continuous, as long as the expression 'immediately' or 'directly' is not used.

[0025] While terms like "first" and "second" are used to describe various components, these components are not limited by these terms. These terms are used merely to distinguish one component from another. Therefore, a "first" component referred to below may also be a "second" component within the technical scope of the present invention.

[0026] The term "at least one" should be understood to include all possible combinations of one or more associated items. For example, "at least one of the first, second, and third items" can mean not only the first, second, or third items, but also any combination of items that can be represented by two or more of the first, second, and third items.

[0027] The features of each of the various embodiments of the present invention can be partially or wholly combined or combined with each other, and various technical connections and operations are possible, and each embodiment can be implemented independently of each other or implemented together in a related relationship.

[0028] One embodiment of the present invention provides an optical film (100). FIG. 1 is a cross-sectional view of an optical film (100) according to one embodiment of the present invention.

[0029] As illustrated in FIG. 1, an optical film (100) according to one embodiment of the present invention includes a light-transmitting substrate (110).

[0030] An optical film (100) according to one embodiment of the present invention has a yellowness change (YI) of 4.5 or less after a light resistance test.

[0031] The above light resistance test is conducted for 300 hours using a Xenon Lamp under the conditions of Daylight filter, 12kW 0.8W / ㎡ @420nm, 30℃ / 30RH% Chamber, 55℃ Black Panel.

[0032] Yellowness was measured in the wavelength range of 360 to 740 nm using a spectrophotometer according to the standard ASTM E313. The spectrophotometer used was a CM-3700D from KONICA MINOLTA.

[0033] Specifically, the yellowness change (YI) after the light fastness test means the difference between the yellowness value of the optical film that underwent the light fastness test and the yellowness value before the light fastness test.

[0034] In the case of an optical film (100) having a yellowness index (YI) of 4.5 or less after a light fastness test, it is suitable for use as a cover window of a display device due to its excellent visibility and light fastness, especially UV light fastness. Since the polymer resin included in the light-transmitting substrate (110) of the optical film (100) has a large number of aromatic rings, if exposed to light with an ultraviolet (UV) wavelength for a long time, yellowing of the optical film (100) may occur. Therefore, over time, the yellowness of the optical film (100) decreases, resulting in a decrease in visibility. On the other hand, an optical film (100) with excellent light fastness may have a small change in yellowness even when exposed to light with an ultraviolet (UV) wavelength, thereby increasing the lifespan of the cover window of the display device.

[0035] According to one embodiment of the present invention, the light-transmitting substrate (110) may include a polymer resin, a filler, and an ultraviolet absorber.

[0036] Polymer resins have excellent bending properties and impact resistance, making them suitable for use as cover windows for flexible display devices. Polymer resins can be included in various shapes and forms, such as in the form of a solid powder in a film, in the form dissolved in a solution, and in the form of a matrix solidified after being dissolved in a solution. Any resin containing the same repeating unit as the present invention can be considered to be the same as the polymer resin of the present invention, regardless of shape and form. Generally, the polymer resin in the film can exist in the form of a matrix solidified by applying a polymer resin solution and then drying it.

[0037] The polymer resin according to one embodiment of the present invention may be any light-transmitting resin. For example, it may include at least one selected from among cycloolefin derivatives, cellulose polymers, ethylene vinyl acetate copolymers, polyester polymers, polystyrene polymers, polyamide polymers, polyamide imide polymers, polyether imide polymers, polyacrylic polymers, polyimide polymers, polyether sulfone polymers, polysulfone polymers, polyethylene polymers, polypropylene polymers, polymethyl pentene polymers, polyvinyl chloride polymers, polyvinylidene chloride polymers, polyvinyl alcohol polymers, polyvinyl acetal polymers, polyether ketone polymers, polyether ether ketone polymers, polymethyl methacrylate polymers, polyethylene terephthalate polymers, polybutylene terephthalate polymers, polyethylene naphthalate polymers, polycarbonate polymers, polyurethane polymers, and epoxy polymers. Preferably, the polymer resin according to one embodiment of the present invention may include at least one of a polyimide-based polymer, a polyamide-based polymer, and a polyamide-imide-based polymer. In particular, polyimide-based polymers, polyamide-based polymers, and polyamide-imide-based polymers have excellent physical properties such as thermal properties, hardness, wear resistance, and flexibility, as well as optical properties such as light transmittance and haze, making them suitable for use as a cover window of a display device. Accordingly, it is preferable that the light-transmitting substrate (110) of the optical film (100) include at least one of a polyimide-based polymer, a polyamide-based polymer, and a polyamide-imide-based polymer. However, the present invention is not limited thereto.

[0038] According to one embodiment of the present invention, the light-transmitting substrate (110) may include a polymer resin including at least one of an imide repeating unit and an amide repeating unit. In the present invention, the imide repeating unit refers to a repeating unit produced by a reaction between a diamine-based compound and a dianhydride-based compound and imidization, and the amide repeating unit refers to a repeating unit produced by a reaction between a diamine-based compound and a dicarbonyl-based compound. The light-transmitting substrate (110) may be any one of a polyimide-based substrate, a polyamide-based substrate, and a polyamide-imide-based substrate. However, one embodiment of the present invention is not limited thereto, and any substrate having light transmission properties may be the light-transmitting substrate (110) according to one embodiment of the present invention.

[0039] According to one embodiment of the present invention, the diamine compound is, for example, m-Tolidine, 2,2'-bis(trifluoromethyl)benzidine (TFDB), 4,4'-Oxydianiline (ODA), para-phenylene diamine (pPDA), meta-phenylene diamine (mPDA), para-Methylene Diamine (pMDA), meta-Methylene Diamine (mMDA), bis aminophenoxy benzene (1,3-bis(3-aminophenoxy) benzene, 133APB), bis aminophenoxy benzene (1,3-bis(4-aminophenoxy) benzene, 134APB), bis amino phenoxy phenyl hexafluoropropane. (2,2'-bis[4(4-aminophenoxy)phenyl] hexafluoropropane, 4BDAF), bis aminophenyl hexafluoropropane (2,2'-bis(3-aminophenyl)hexafluoropropane, 33-6F), bis aminophenyl hexafluoropropane (2,2'-bis(4-aminophenyl)hexafluoropropane, 44-6F), bis aminophenyl sulfone (bis(4-aminophenyl)sulfone, 4DDS), bis aminophenyl sulfone (bis(3-aminophenyl)sulfone, 3DDS), cyclohexanediamine (1,3-Cyclohexanediamine, 13CHD), cyclohexanediamine (1,4-Cyclohexanediamine, 14CHD), bis amino phenoxy phenylpropane (2,2-Bis[4-(4-aminophenoxy)-phenyl]propane, 6HMDA), bis Aminohydroxyphenyl hexafluoropropane (2,2-Bis(3-amino-4-hydroxy-phenyl)-hexafluoropropane, DBOH) and bisaminophenoxy diphenyl sulfone (4,It may contain at least one of 4'-Bis(3-amino phenoxy) diphenyl sulfone, DBSDA.

[0040] More specifically, according to one embodiment of the present invention, the diamine compound may include at least one of, for example, m-Tolidine, 2,2'-bis(trifluoromethyl)benzidine (TFDB), para-phenylene diamine (pPDA), meta-phenylene diamine (mPDA), para-Methylene Diamine (pMDA), meta-Methylene Diamine (mMDA), bis(4-aminophenyl)sulfone (4DDS), bis(3-aminophenyl)sulfone (3DDS), and bisaminophenoxy diphenyl sulfone (4,4'-Bis(3-amino phenoxy) diphenyl sulfone (DBSDA). However, one embodiment of the present invention is not limited thereto.

[0041] According to one embodiment of the present invention, the dianhydride compound is, for example, isopropylideneiphenoxy bisphthalic anhydride (4,4′-(4,4′-Isopropylidenediphenoxy)bis(phthalic anhydride, 4IBA), biphenyl tetracarboxylic dianhydride (3,3,4,4-Biphenyltetracarboxylic dianhydride, BPDA), 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA), cyclobutane-1,2,3,4-tetracarboxylic dianhydride (CBDA), 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic anhydride (TDA), pyromellitic acid. It may include at least one of 1,2,4,5-benzene tetracarboxylic dianhydride (pyromellicticacid dianhydride, PMDA), 3,3,4,4-Benzophenone tetracarboxylic dianhydride (BTDA), 4,4-Oxydiphthalic dianhydride (ODPA), Bis(3,4dicarboxyphenyl)dimethyl-silane dianhydride (SiDA), 4,4-bis(3,4-dicarboxyphenoxy)diphenyl sulfide dianhydride (BDSDA), and sulfonyldiphthalic anhydride (SO2DPA).

[0042] More specifically, according to one embodiment of the present invention, the dianhydride compound is, for example, isopropylideneiphenoxy bisphthalic anhydride (4,4'-(4,4'-Isopropylidenediphenoxy)bis(phthalic anhydride, 4IBA), biphenyl tetracarboxylic dianhydride (3,3,4,4-Biphenyltetracarboxylic dianhydride, BPDA), 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA), cyclobutane-1,2,3,4-tetracarboxylic dianhydride (CBDA), pyromellic acid dianhydride (1,2,4,5-benzene tetracarboxylic dianhydride, pyromellicticacid dianhydride, PMDA), benzophenone tetracarboxylic dianhydride. (3,3,4,4-Benzophenone tetracarboxylic dianhydride, BTDA) and oxydiphthalic dianhydride (4,4-Oxydiphthalic dianhydride, ODPA). However, one embodiment of the present invention is not limited thereto.

[0043] According to one embodiment of the present invention, the dicarbonyl compound may include, for example, at least one of terephthaloyl chloride (TPC), phthaloyl chloride, isophthaloyl chloride (IPC), biphenyldicarbonyl chloride (DPDOC), 4,4'-oxybis(benzoyl chloride, OBBOC), naphthalene-2,3-dicarbonyl dichloride, and cyclohexanedicarbonyldichloride (1,4-Cyclohexanedicabonyldichloride, CHDOC).

[0044] More specifically, according to one embodiment of the present invention, the dicarbonyl compound may include, for example, at least one of terephthaloyl chloride (TPC), phthaloyl chloride, and isophthaloyl chloride (IPC). However, one embodiment of the present invention is not limited thereto.

[0045] The light-transmitting substrate (110) may have a thickness sufficient to allow the optical film (100) to protect the display panel. For example, the light-transmitting substrate (110) may have a thickness of 10 to 100 μm. The thickness of the light-transmitting substrate (110) may be the same as the thickness of the optical film (100).

[0046] According to one embodiment of the present invention, the light-transmitting substrate (110) includes a filler. The filler may have a fiber shape or a rod shape. Hereinafter, a shape having a length greater than its diameter is referred to as a fiber shape. The fiber shape may also be referred to as a filament shape. According to one embodiment of the present invention, the length of the filler may be at least twice its diameter.

[0047] According to one embodiment of the present invention, the filler has a fiber shape and can intertwine the polymer chains constituting the light-transmitting substrate (110). As a result, the stability and arrangement characteristics of the polymer chains are improved, so that the mechanical properties of the light-transmitting substrate (110) can be improved, and the mechanical properties of the optical film (100) can also be improved.

[0048] According to one embodiment of the present invention, the Aspect Ratio of the filler may be in the range of 10 to 500. The Aspect Ratio of the filler is the ratio of the length to the diameter of the filler.

[0049] If the aspect ratio of the filler is less than 10, the filler is not long enough to sufficiently exhibit the function of intertwining the polymer chains, and thus the effect of improving the stability and arrangement characteristics of the polymer chains may not be sufficiently exhibited.

[0050] When the Aspect Ratio of the filler exceeds 500, the length of the filler is excessively long, which reduces the dispersibility of the filler and may cause agglomeration of the filler within the light-transmitting substrate (110). As a result, the light transmittance of the optical film (100) may decrease, haze may increase, and the optical properties of the optical film (100) may deteriorate. In addition, the mechanical strength of the optical film (100) may decrease in the portion where the filler agglomeration occurs, and as a result, the modulus of the optical film (100) may decrease and the mechanical strength of the optical film (100) may decrease.

[0051] According to one embodiment of the present invention, the length of the filler may be in the range of 200 to 4,000 nm.

[0052] If the length of the filler is less than 200 nm, the function of the filler to interweave polymer chains may not be sufficiently exerted.

[0053] When the length of the filler exceeds 4,000 nm, the dispersibility of the filler may be reduced, resulting in aggregation of the filler within the light-transmitting substrate (110) and gelation easily occurring due to interaction with the polymer chain. Accordingly, the light transmittance of the optical film (100) may be reduced, haze may be increased, and the optical properties of the optical film (100) may be deteriorated.

[0054] According to one embodiment of the present invention, the diameter of the filler may be in the range of 2 to 10 nm.

[0055] If the diameter of the filler is less than 2 nm, the stability of the filler may be reduced, and the filler may break or crumble, contaminating the optical film (100), thereby increasing the haze of the optical film (100).

[0056] If the diameter of the filler exceeds 10 nm, it may be difficult for the filler to have a fiber shape, or the function of intertwining polymer chains may be reduced, and the optical film (100) may increase or the transmittance may decrease.

[0057] According to one embodiment of the present invention, the length and diameter of the filler can be measured by transmission electron microscopy (TEM).

[0058] There are no specific limitations on the type of filler. Any filler having a fiber shape can be used as a filler according to an embodiment of the present invention without limitation. The filler may be inorganic or organic. The filler may include at least one of inorganic fibers, organic fibers, and organic-inorganic composite fibers.

[0059] More specifically, the filler may have a fiber shape. For example, the filler may have a single-strand fiber shape, a multi-strand fiber shape, or a shape in which multiple strands are arranged in a branched form around a single central strand.

[0060] According to one embodiment of the present invention, the filler may include at least one of glass fiber, aluminum fiber, and fluoride fiber.

[0061] Glass fibers contain SiO2 and may contain other components in addition to SiO2. Aluminum fibers contain Al2O3 and may contain other components in addition to Al2O3. Fluorine fibers may contain at least one of PTFE (Polytetrafluoroethylene) and PVDF (Polyvinylidene Fluoride), and may contain other components in addition to PTFE and PVDF.

[0062] According to one embodiment of the present invention, the filler may include at least one of aluminum oxide hydroxide, SiO2, Al2O3, PTFE (Polytetrafluoroethylene), and PVDF (Polyvinylidene Fluoride).

[0063] According to one embodiment of the present invention, the filler may be surface-treated. For example, a fiber surface-treated with an organic compound group having an alkoxy group may be used as the filler.

[0064] According to one embodiment of the present invention, the aluminum fiber may include at least one of aluminum oxide hydroxide and Al2O3. The aluminum oxide hydroxide is also called boehmite and may be represented by γ-AlO(OH). More specifically, the aluminum oxide hydroxide may include a structure represented by any one of the following chemical formulas 1, 2, and 3.

[0065] [Chemical Formula 1]

[0066]

[0067] [Chemical Formula 2]

[0068]

[0069] [Chemical Formula 3]

[0070]

[0071] Here, n is in the range of 100 to 20,000, m is in the range of 50 to 10,000, and p is in the range of 50 to 10,000.

[0072] To help understand the structure of the filler, by expanding the structures of Chemical Formulas 1, 2 and 3, the filler may include a structure represented by any one of Chemical Formulas 4, 5 and 6 below.

[0073] The structure represented by Chemical Formula 1 can be represented, for example, by Chemical Formula 4 below. Chemical Formula 4 below corresponds to the case where n is 3 in Chemical Formula 1.

[0074] [Chemical Formula 4]

[0075]

[0076] The structure represented by Chemical Formula 2 can be represented, for example, by Chemical Formula 5 below. Chemical Formula 5 below corresponds to the case where m is 4 in Chemical Formula 2.

[0077] [Chemical Formula 5]

[0078]

[0079] The structure represented by Chemical Formula 3 can be represented, for example, by Chemical Formula 6 below. Chemical Formula 6 below corresponds to the case where p is 5 in Chemical Formula 3.

[0080] [Chemical Formula 6]

[0081]

[0082] In the above chemical formulas 4 to 6, “*” indicates a bonding position.

[0083] According to one embodiment of the present invention, when a filler is added, appropriate light scattering may occur due to the filler, thereby improving the optical properties of the optical film (100). To enhance the light scattering effect, the content of the filler included in the optical film (100) may be adjusted.

[0084] According to one embodiment of the present invention, the content of the filler may be 1 to 40 parts by weight relative to 100 parts by weight of the polymer resin. More specifically, the content of the filler may be adjusted to 4 to 30 parts by weight, or may be 5 to 20 parts by weight.

[0085] When the content of the filler is less than 1 part by weight, the light scattering effect by the filler may be minimal, so the effect of improving the light transmittance of the optical film (100) may be hardly observed, and the function of the filler to link the polymer chains may not be sufficiently exerted.

[0086] On the other hand, when the content of the filler exceeds 40 parts by weight, the dispersibility of the filler may be reduced, so that the haze of the optical film (100) may be reduced, and the filler may be coagulated due to the excessive amount of filler, and the coagulated filler may block light, so that the light transmittance of the optical film (100) may be reduced.

[0087] According to one embodiment of the present invention, the light-transmitting substrate (110) includes an ultraviolet absorber.

[0088] Typically, fillers are added as filler dispersions to manufacture optical films. Furthermore, when a UV absorber is further included to manufacture an optical film (100), the interaction between the added UV absorber and the filler dispersion not only reduces the effectiveness of the UV absorber, but also causes yellowing during curing. Consequently, when a filler dispersion and a UV absorber are used simultaneously, the light resistance is lowered and yellowness increases compared to when only the UV absorber is used.

[0089] That is, since the filler dispersion for adding filler is an acid solution, a non-nitrogen-based ultraviolet absorber that has little interaction with the filler dispersion is required to prevent the effect of the ultraviolet absorber from decreasing and to prevent yellowing from occurring during curing.

[0090] Specifically, the ultraviolet absorbent according to the present invention has a pH reduction rate of 5% or more when reacted with acetic acid.

[0091] At this time, the pH decrease rate means the rate of decrease from the pH value immediately after dissolving the ultraviolet absorbent in DMAc at a concentration of 1 wt% to the pH value measured after additionally adding acetic acid at a content of 2 mol% relative to the dissolved ultraviolet absorbent.

[0092] The above pH is the average of three measurements using Saven Compact from METTLER TOLEDO.

[0093] When the UV absorbent according to the present invention reacts with acetic acid and has a pH reduction rate of 5% or more, the interaction between the acetic acid and the UV absorbent can be considered very small. In other words, the UV absorbent having a pH reduction rate of 5% or more when reacted with acetic acid can be considered to have a very small interaction with the filler dispersion, thereby preventing the UV absorbent from losing its effectiveness and preventing yellowing during curing. As a result, even when the filler dispersion and the UV absorbent are used simultaneously, the light resistance effect is not reduced and the yellowness does not increase.

[0094] On the other hand, if the pH decrease rate of the ultraviolet absorbent according to the present invention when reacting with acetic acid is less than 5%, it can be seen that the interaction between acetic acid and the ultraviolet absorbent is very large. That is, if the pH decrease rate when reacting with acetic acid is less than 5%, not only is the effect of the ultraviolet absorbent reduced due to the interaction between the ultraviolet absorbent and the filler dispersion, but there is also a problem of causing yellowing during curing. As a result, when the filler dispersion and the ultraviolet absorbent are used simultaneously, the light resistance effect is lowered and the yellowness increases compared to when the ultraviolet absorbent alone is used.

[0095] According to one embodiment of the present invention, the ultraviolet absorbent may include a compound represented by the following chemical formula 7.

[0096] [Chemical Formula 7]

[0097]

[0098] According to one embodiment of the present invention, the light-transmitting substrate (110) may include 2 to 10 parts by weight of an ultraviolet absorbent per 100 parts by weight of the polymer resin.

[0099] When less than 2 parts by weight of ultraviolet absorber is included relative to 100 parts by weight of polymer resin, the effect of improving light fastness is minimal, and the yellowness change (YI) after the light fastness test exceeds 4.5. Conversely, when more than 10 parts by weight of ultraviolet absorber is included relative to 100 parts by weight of polymer resin, the initial yellowness before the light fastness test exceeds 4.0, and a problem of ultraviolet absorber dissolution may occur when the optical film (101) is stored for a long period of time.

[0100] According to one embodiment of the present invention, the optical film (101) may further include a primer layer (120) on top of the light-transmitting substrate (110). Fig. 2 is a cross-sectional view of an optical film (101) further including a primer layer (120).

[0101] As illustrated in FIG. 2, an optical film (101) further including a primer layer (120) can be laminated in the order of a light-transmitting substrate (110) and a primer layer (120).

[0102] The primer layer (120) of the present invention may include a curable resin. According to one embodiment of the present invention, the curable resin may include at least one selected from an acrylic resin, a urethane resin, and a siloxane resin.

[0103] According to one embodiment of the present invention, the primer layer (120) of the present invention may further include at least one of an ultraviolet absorber and a pigment.

[0104] According to one embodiment of the present invention, the primer layer (120) may have a thickness of 0.01 to 1 μm. Preferably, the primer layer (120) may have a thickness of 0.1 to 0.5 μm. However, the present invention is not limited thereto.

[0105] According to one embodiment of the present invention, the optical film (102) may further include a hard coating layer (130) on top of the light-transmitting substrate (110). FIG. 3 is a cross-sectional view of an optical film (102) further including a hard coating layer (130).

[0106] As illustrated in FIG. 3, an optical film (102) further including a hard coating layer (130) can be laminated in the order of a light-transmitting substrate (110) and a hard coating layer (130).

[0107] The hard coating layer (130) is a layer that protects the optical film (102) and the adherend to which the optical film (102) is attached from the external environment. According to one embodiment of the present invention, the hard coating layer (130) may include at least one of a siloxane-based resin, an acrylic-based resin, a urethane-based resin, and an epoxy-based resin.

[0108] According to one embodiment of the present invention, the hard coating layer (130) may have a thickness of 1 to 10 μm, and preferably, a thickness of 1 to 5 μm. However, the present invention is not limited thereto.

[0109] According to one embodiment of the present invention, the optical film may include both a primer layer (120) and a hard coating layer (130) added on top of a light-transmitting substrate (110). The optical film further including the primer layer (120) and the hard coating layer (130) may be laminated in the order of the light-transmitting substrate (110), the primer layer (120), and the hard coating layer (130).

[0110] According to one embodiment of the present invention, the optical film (100) may have light-transmitting and flexible properties. For example, the optical film according to one embodiment of the present invention may have bending properties, folding properties, and rollable properties.

[0111] According to one embodiment of the present invention, the optical film (100) may have a yellowness index (YI) of 4.0 or less before a light resistance test based on a thickness of 50 μm.

[0112] Yellowness was measured in the wavelength range of 360 to 740 nm using a spectrophotometer according to the standard ASTM E313. The spectrophotometer used was a CM-3700D from KONICA MINOLTA.

[0113] An optical film (100) according to one embodiment of the present invention may have a modulus of 6.5 GPa or more based on a thickness of 50 μm. At this time, the modulus was measured using a universal tensile tester (e.g., INSTRON) according to the standard specification ASTM D885 at 25°C, 50 RH%, Load Cell 30 KN, Grip 250 N, specimen size 10 X 50 mm, and tensile speed 25 mm / min.

[0114] An optical film (100) according to one embodiment of the present invention can be applied to a display device to protect the display surface of a display panel. The optical film (100) according to one embodiment of the present invention can have a thickness sufficient to protect the display panel. For example, the optical film (100) can have a thickness of 20 to 120 μm. However, the present invention is not limited thereto.

[0115] Hereinafter, with reference to FIGS. 4 and 5, a display device using an optical film (100) according to one embodiment of the present invention will be described.

[0116] FIG. 4 is a cross-sectional view of a portion of a display device (200) according to another embodiment of the present invention, and FIG. 5 is an enlarged cross-sectional view of a portion “P” of FIG. 4.

[0117] Referring to FIG. 4, 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). The optical film (100) of FIG. 4 may be the optical film (101) of FIG. 2 or the optical film (102) of FIG. 3.

[0118] Referring to FIGS. 4 and 5, 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) disclosed in FIGS. 4 and 5 is an organic light-emitting display device.

[0119] The substrate (510) may be made of glass or plastic. Specifically, the substrate (510) may be made of plastic such as a polyimide-based resin. Although not shown, a buffer layer may be disposed on the substrate (510).

[0120] A thin film transistor (TFT) is disposed on a substrate (510). The thin film transistor (TFT) includes a semiconductor layer (520), a gate electrode (530) that is insulated from the semiconductor layer (520) and overlaps at least a portion of the semiconductor layer (520), a source electrode (541) connected to the semiconductor layer (520), and a drain electrode (542) that is spaced apart from the source electrode (541) and connected to the semiconductor layer (520).

[0121] Referring to FIG. 5, a gate insulating film (535) is disposed between a gate electrode (530) and a 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).

[0122] A planarization film (552) is placed on a thin film transistor (TFT) to planarize the upper portion of the thin film transistor (TFT).

[0123] The first electrode (571) is placed on the planarization film (552). The first electrode (571) is connected to a thin film transistor (TFT) through a contact hole provided in the planarization film (552).

[0124] The bank layer (580) is disposed on a portion of the first electrode (571) and the planarization film (552) to define a pixel area or a light-emitting area. For example, the bank layer (580) may be disposed in a matrix structure in a boundary area between a plurality of pixels, thereby defining a pixel area by the bank layer (580).

[0125] An 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 may include two or more light-emitting layers stacked one above the other. Light having any one of red, green, and blue colors may be emitted from the organic light-emitting layer (572), and white light may also be emitted.

[0126] The second electrode (573) is placed on the organic light-emitting layer (572).

[0127] A first electrode (571), an organic light-emitting layer (572), and a second electrode (573) can be laminated to form an organic light-emitting element (570).

[0128] 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.

[0129] 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 at least one organic film and at least one inorganic film may be disposed alternately.

[0130] An optical film (100) is placed on a display panel (501) having the laminated structure described above.

[0131] Hereinafter, the present invention will be described in more detail with reference to exemplary embodiments and comparative examples. However, the present invention is not limited to the embodiments and comparative examples described below.

[0132] Manufacturing Example 1: Manufacturing of polyimide-based polymer solid content

[0133] While passing nitrogen through a 1 L reactor equipped with a stirrer, nitrogen injection device, dropping funnel, temperature controller, and condenser, 800.50 g of DMAc (N,N-Dimethylacetamide) was charged, the temperature of the reactor was adjusted to 25°C, and 29.796 g (0.12 mol) of 3DDS (bis (3-aminophenyl) sulfone) was dissolved. After 3DDS was completely dissolved, 25.476 g (0.12 mol) of m-Tolidine was added and completely dissolved, and the solution was maintained at 25°C. Here, 62.459 g (0.12 mol) of 4IBA (4,4′-(4,4′-Isopropylidenediphenoxy)bis(phthalic anhydride)) was added and stirred for 3 hours to completely dissolve 4IBA. Then, 23.533 g (0.12 mol) of CBDA (Cyclobutane-1,2,3,4-tetracarboxylic dianhydride) was added and completely dissolved. The reaction was conducted at 25°C for 12 hours to ensure sufficient polymerization, obtaining a polymer solution with a solid concentration of 15 wt%.

[0134] 9.49 g of pyridine and 12.25 g of acetic anhydride were added to the obtained polymer solution, stirred for 30 minutes, stirred again at 70°C for 1 hour, cooled to room temperature, 20 L of methanol was added to the obtained polymer solution to precipitate a solid, filter and pulverize the precipitated solid, and then washed again with 2 L of methanol, followed by drying in a vacuum at 100°C for 6 hours to obtain a polyimide polymer solid in powder form.

[0135] Manufacturing Example 2: Manufacturing of polyimide-based polymer solid content

[0136] While passing nitrogen into a 1 L reactor equipped with a stirrer, nitrogen injection device, dropping funnel, temperature controller, and condenser, 765.09 g of DMAc (N,N-Dimethylacetamide) was charged, and the temperature of the reactor was adjusted to 25℃, and 18.16 g (0.168 mol) of mPDA (meta-phenylene diamine) was dissolved. After mPDA was completely dissolved, 15.28 g (0.072 mol) of m-Tolidine was added and completely dissolved, and the solution was maintained at 25℃. 87.44 g (0.168 mol) of 4IBA (4,4′-(4,4′-Isopropylidenediphenoxy)bis(phthalic anhydride)) was added and stirred for 3 hours to completely dissolve 4IBA. After lowering the reactor temperature to 10°C, 14.12 g (0.072 mol) of TPC (Terephthaloyl Chloride) was added and reacted at 25°C for 12 hours to obtain a polymer solution with a solid concentration of 15 wt%.

[0137] 9.49 g of pyridine and 12.25 g of acetic anhydride were added to the obtained polymer solution, stirred for 30 minutes, stirred again at 70°C for 1 hour, cooled to room temperature, 20 L of methanol was added to the obtained polymer solution to precipitate a solid, filter and pulverize the precipitated solid, and then washed again with 2 L of methanol, followed by drying in a vacuum at 100°C for 6 hours to obtain a polyimide polymer solid in powder form.

[0138] Example 1

[0139] After filling a 500 ml reactor with 331.5 g of DMAc, 2.68 g of Eversorb320, a UV stabilizer, was added and completely dissolved. Then, 20.54 g of an alumina fiber dispersion (Aluminum oxide hydroxide of the chemical formula 3 according to the present invention), in which alumina fibers having an average particle diameter of 4 nm and an average length of 1,600 nm were dispersed in DMAc at a content of 9.8 wt%, was added and dispersed. Thereafter, the temperature of the reactor was adjusted to 10 ℃, and when the temperature was reached, 44.74 g of the polyimide-based resin powder, which was a solid powder manufactured in Manufacturing Example 1, was added, followed by stirring for 1 hour and then increasing the temperature to 25 ℃ to manufacture a transparent liquid polyimide-based resin solution in which a filler and a UV stabilizer were dispersed.

[0140] After obtaining a polyimide resin solution, casting was performed. There are no particular limitations on the type of casting substrate. Examples of casting substrates that can be used include glass substrates, stainless steel (SUS) substrates, and Teflon substrates. According to one embodiment of the present invention, a glass substrate can be used as the casting substrate.

[0141] Specifically, the obtained resin solution was applied to a glass substrate and cast. To improve the orientation of the filler, the resin solution was applied to the glass substrate (casting substrate) and then cast while applying a coating pressure of 15 kPa in a direction perpendicular to the glass substrate. As a result, a cast film was produced.

[0142] In order to maintain the orientation of the filler during the drying process of the cast film, the film was manufactured by placing it in a hot air oven at 80°C and slowly drying it to 120°C for about 40 minutes at a rate of 1°C / min, and the manufactured film was peeled off from the glass substrate and fixed to a frame with pins.

[0143] The frame with the film fixed thereon was placed in a vacuum oven and slowly heated from 100°C to 280°C for 2 hours, then slowly cooled and separated from the frame to obtain an optical film. The optical film was then heat-treated again at 250°C for 5 minutes. As a result, a 50 μm thick optical film was completed.

[0144] Example 2

[0145] After filling a 500 ml reactor with 314.1 g of DMAc, 2.57 g of Eversorb320, a UV stabilizer, was added and completely dissolved. Then, 39.81 g of an alumina fiber dispersion (Aluminum oxide hydroxide of the chemical formula 3 according to the present invention), in which alumina fibers having an average particle diameter of 4 nm and an average length of 1,600 nm were dispersed in DMAc at a content of 9.8 wt%, was added and dispersed. Thereafter, the temperature of the reactor was adjusted to 10 ℃, and when the temperature was reached, 42.87 g of the polyimide-based resin powder, which was a solid powder manufactured in Manufacturing Example 1, was added, followed by stirring for 1 hour and then increasing the temperature to 25 ℃ to manufacture a transparent liquid polyimide-based resin solution in which a filler and a UV stabilizer were dispersed.

[0146] An optical film (100) was manufactured in the same manner as Example 1, except for the process of manufacturing a polyimide resin solution, according to the conditions of Table 1, and this was referred to as Example 2.

[0147] Example 3

[0148] According to the conditions of Table 1, an optical film (100) was manufactured in the same manner as Example 2, except that the polyimide-based resin powder of the solid powder manufactured in Manufacturing Example 2 was used instead of the polyimide-based resin powder of the solid powder manufactured in Manufacturing Example 1, and this was referred to as Example 3.

[0149] Example 4

[0150] After filling a 500 ml reactor with 332.2 g of DMAc, 0.86 g of Eversorb320, a UV stabilizer, was added and completely dissolved. Then, 19.68 g of an alumina fiber dispersion (Aluminum oxide hydroxide of the chemical formula 3 according to the present invention), in which alumina fibers having an average particle diameter of 4 nm and an average length of 1,600 nm were dispersed in DMAc at a content of 9.8 wt%, was added and dispersed. Thereafter, the temperature of the reactor was adjusted to 10 ℃, and when the temperature was reached, 42.87 g of the polyimide-based resin powder, which was a solid powder manufactured in Manufacturing Example 1, was added, followed by stirring for 1 hour and then increasing the temperature to 25 ℃ to manufacture a transparent liquid polyimide-based resin solution in which a filler and a UV stabilizer were dispersed.

[0151] An optical film (100) was manufactured in the same manner as Example 1, except for the process of manufacturing a polyimide resin solution, according to the conditions of Table 1, and this was referred to as Example 4.

[0152] Example 5

[0153] After filling a 500 ml reactor with 332.2 g of DMAc, 4.29 g of Eversorb320, a UV stabilizer, was added and completely dissolved. Then, 19.68 g of an alumina fiber dispersion (Aluminum oxide hydroxide of the chemical formula 3 according to the present invention), in which alumina fibers having an average particle diameter of 4 nm and an average length of 1,600 nm were dispersed in DMAc at a content of 9.8 wt%, was added and dispersed. Thereafter, the temperature of the reactor was adjusted to 10 ℃, and when the temperature was reached, 42.87 g of the polyimide-based resin powder, which was a solid powder manufactured in Manufacturing Example 1, was added, followed by stirring for 1 hour and then increasing the temperature to 25 ℃ to manufacture a transparent liquid polyimide-based resin solution in which a filler and a UV stabilizer were dispersed.

[0154] An optical film (100) was manufactured in the same manner as Example 1, except for the process of manufacturing a polyimide resin solution, according to the conditions of Table 1, and this was referred to as Example 5.

[0155] Comparative Example 1

[0156] According to the conditions of Table 1, an optical film (100) was manufactured in the same manner as Example 1, and each of these was referred to as Comparative Example 1.

[0157] Comparative Example 2

[0158] According to the conditions of Table 1, an optical film (100) was manufactured in the same manner as Example 2, and each of these was referred to as Comparative Example 2.

[0159] Comparative Example 3

[0160] According to the conditions of Table 1, an optical film (100) was manufactured in the same manner as Comparative Example 2, and each was referred to as Comparative Example 3.

[0161] Comparative Example 4

[0162] According to the conditions of Table 1, an optical film (100) was manufactured in the same manner as Example 3, and each was referred to as Comparative Example 4.

[0163] Comparative Example 5

[0164] An optical film (100) was manufactured in the same manner as Example 4 under the conditions of Table 1, except that 0.43 g of Eversorb320, a UV stabilizer, was added, and each was referred to as Comparative Example 5.

[0165] Comparative Example 6

[0166] An optical film (100) was manufactured in the same manner as Comparative Example 5 under the conditions of Table 1, except that 4.72 g of Eversorb320, a UV stabilizer, was added, and each was referred to as Comparative Example 6.

[0167] Comparative Example 7

[0168] After filling a 500 ml reactor with 334.4 g of DMAc, 2.57 g of Eversorb320, a UV stabilizer, was added and completely dissolved. Then, 19.50 g of a silica (SiO2) dispersion (DMAc-ST, Nissan Chemical Industries), in which silica spherical particles with an average particle diameter of 13 nm were dispersed in DMAc at a content of 20 wt%, was added and dispersed. After that, the temperature of the reactor was adjusted to 10 ℃, and when the temperature was reached, 42.87 g of the polyimide resin powder, which was a solid powder manufactured in Manufacturing Example 1, was added, followed by stirring for 1 hour and increasing the temperature to 25 ℃ to manufacture a transparent liquid polyimide resin solution in which the filler and UV stabilizer were dispersed.

[0169] An optical film (100) was manufactured in the same manner as Example 1 under the conditions of Table 1, except for the process of manufacturing a polyimide resin solution, and this was referred to as Comparative Example 7.

[0170] ClassificationPolymer (molar ratio)Filler typeFiller content (weight parts)UV absorber typeUV absorber content (weight parts)Diaminedianhydridedicarbonyl3DDSmPDAm-Tolidine4IBACBDATPCExample 150-505050-Filler 14.5Eversorb 3206Example 250-505050-Filler 19.1Eversorb 3206Example 3-703070-30Filler 19.1Eversorb 3206Example 450-505050-Filler 14.5Eversorb 3202Example 550-505050-Filler 14.5Eversorb 32010Comparative example 150-505050-Filler 14.5 Non-injected - Comparative Example 250-505050-Filler 19.1Eversorb 1096 Comparative Example 350-505050-Filler 19.1LA326 Comparative Example 4-703070-30Filler 19.1 Non-injected - Comparative Example 550-505050-Filler 14.5Eversorb 3201 Comparative Example 650-505050-Filler 14.5Eversorb 32011 Comparative Example 750-505050-Filler 29.1Eversorb 3206

[0171] Filler 1 according to Table 1 is aluminum oxide hydroxide with an aspect ratio of 400 (length 1600 nm, diameter 4 nm), and filler 2 is spherical silica particles with an average particle size of 13 nm. Eversorb 320 according to Table 1 is a compound represented by the above chemical formula 7.

[0172] Eversorb 109 and LA32 according to Table 1 are compounds represented by the following chemical formulas 8 and 9, respectively.

[0173] [Chemical Formula 8]

[0174]

[0175] [Chemical Formula 9]

[0176]

[0177] In Table 1, the molar ratio represents the relative molar ratio for 100 moles of the total diamine.

[0178] In Table 1, the weight part refers to the weight of the ultraviolet absorber added per 100 weight parts of the polyimide-based polymer solid content. This corresponds to the weight of the ultraviolet absorber added per 100 weight parts of the polymer resin according to the present invention.

[0179] The following physical properties were measured for the optical films manufactured in Examples 1 and 2 and Comparative Examples 1 to 4.

[0180] (1) Measurement of pH and pH decrease rate before and after adding acetic acid

[0181] pH is the average of three measurements taken using METTLER TOLEDO's Saven Compact.

[0182] Specifically, the pH decrease rate means the rate of decrease from the pH value immediately after dissolving the ultraviolet absorbent in DMAc at a concentration of 1 wt% to the pH value measured after additionally adding acetic acid at a content of 2 mol% relative to the dissolved ultraviolet absorbent.

[0183] (2) Modulus measurement

[0184] Yellowness was measured based on an optical film with a thickness of 50 μm. Specifically, the modulus of the optical film was measured using an Instron universal tensile tester (MODEL 5967) according to the ASTM D885 method.

[0185] - Measurement standard within three hours after film production

[0186] - Temperature: 25 ℃

[0187] - Humidity: 50 RH%

[0188] - Load Cell: 30KN, Grip: 250N

[0189] - Specimen size: 10mm X 50mm, Tensile speed: 25mm / min

[0190] (3) Yellowness index (YI) measurement before light fastness test

[0191] Yellowness was measured based on an optical film having a thickness of 50 ㎛. Specifically, the yellowness (YI) before the light fastness test refers to the yellowness measured before the light fastness test according to the present invention, and the yellowness was measured in the wavelength range of 360 to 740 nm using a spectrophotometer according to the standard specification ASTM E313. The spectrophotometer used was CM-3700D from KONICA MINOLTA.

[0192] (4) Yellowness index (YI) measurement after light fastness test

[0193] The yellowness index (YI) after the light fastness test refers to the yellowness measured after the light fastness test according to the present invention, and the method for measuring the yellowness is the same as the yellowness before the light fastness test.

[0194] The above light resistance test is conducted for 300 hours using a Xenon Lamp under the conditions of Daylight filter, 12kW 0.8W / ㎡ @420nm, 30℃ / 30RH% Chamber, 55℃ Black Panel.

[0195] (5) Measurement of yellowness change (YI) after light fastness test

[0196] It means the value obtained by subtracting the yellowness value before the light fastness test from the yellowness value measured after the above light fastness test.

[0197] The measurement results are shown in Table 2 below.

[0198] ClassificationAcetic acid additionModulus (GPa)Yellowness before lightfastness testYellowness after lightfastness testYellowness after lightfastness testYellowness change (YI)Before additionPHAfter additionPHReduction rate%Example 113.1712.197.447.73.46.73.3Example 213.1712.197.448.23.27.03.8Example 313.1712.197.448.83.57.74.2Example 413.1712.197.447.63.07.54.5Example 513.1712.197.447.93.66.52.9Comparative Example 1---7.63.01 0.37.3Comparative Example 2 11.2011.180.188.126.4--Comparative Example 3 11.0510.792.358.315.3--Comparative Example 4---8.22.111.28.1Comparative Example 5 13.1712.197.447.43.48.34.9Comparative Example 6 13.1712.197.447.44.37.33.0Comparative Example 7 13.1712.197.446.44.98.63.7

[0199] In Table 2, the optical films of Comparative Examples 2 and 3 did not include the ultraviolet absorber according to one embodiment of the present invention, and therefore, the yellowness value before the light resistance test was excessively high at 10 or more, so the light resistance test was not performed.

[0200] In Table 2, it can be seen that the optical films of Comparative Examples 1 and 4 did not contain a UV absorber, and thus the yellowness change value after the light resistance test did not satisfy the standard.

[0201] It can be seen from Table 2 that the optical films of Comparative Examples 6 and 7 did not satisfy the content conditions of the ultraviolet absorber, and thus the yellowness values ​​before the light resistance test did not meet the standards.

[0202] As disclosed in the measurement results of Table 2, it can be seen that the optical film (100) according to the embodiment of the present invention satisfied the standards in all of the pH decrease rate upon addition of acetic acid, modulus, and yellowness change value after light resistance test.

Claims

1. Contains a light-transmitting substrate, The above light-transmitting substrate is, polymer resin; Filler having a fiber shape; and Contains a non-nitrogen based ultraviolet absorber; The yellowness index (YI) before the light fastness test is 4.0 or less, Optical films having a yellowness index (YI) of 4.5 or less after a light fastness test: The above light resistance test is conducted for 300 hours using a Xenon Lamp under the conditions of Daylight filter, 12kW 0.8W / ㎡ @420㎚, 30℃ / 30RH% Chamber, 55℃ Black Panel.

2. In paragraph 1, The above filler is an optical film having an aspect ratio of 10 to 500: The above Aspect Ratio is the ratio of the length to the diameter of the filler.

3. In paragraph 2, An optical film wherein the filler has a length of 200 to 4,000 nm and a diameter of 2 to 10 nm.

4. In paragraph 1, The above filler is an optical film, which is aluminum oxide hydroxide.

5. In paragraph 1, An optical film having a content of the filler of 1 to 40 parts by weight based on 100 parts by weight of the polymer resin.

6. In paragraph 1, An optical film, wherein the polymer resin comprises at least one of an imide repeating unit and an amide repeating unit.

7. In paragraph 1, The above ultraviolet absorbent is an optical film having a pH reduction rate of 5% or more when reacted with acetic acid: The above pH reduction rate means the rate of decrease from the pH value immediately after dissolving the UV absorbent in DMAc at a concentration of 1 wt% to the pH value measured after additionally adding acetic acid at a content of 2 mol% relative to the dissolved UV absorbent. The above pH is the average of three measurements using Saven Compact from METTLER TOLEDO.

8. In paragraph 7, The above ultraviolet absorbent is an optical film comprising a compound represented by the following chemical formula 7: [Chemical formula 7] 9. In paragraph 1, An optical film, wherein the ultraviolet absorbent has a content of 2 to 10 parts by weight based on 100 parts by weight of the polymer resin.

10. In paragraph 1, An optical film having a modulus of 6.5 GPa or more at a thickness of 50 ㎛.

11. Display panel; and A display device comprising an optical film according to any one of claims 1 to 10, arranged on the display panel.

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