ANTI-REFLECTIVE FILM, POLARIZING PLATE, AND DISPLAY APPARATUS

Abstract

The present invention relates to an anti-reflective film that comprises a low moisture permeable polymer film, a hard coating layer and a low refractive index layer and that has low reflectance deviation and light transmittance deviation, can simultaneously realize high scratch resistance and anti-fouling property, and can increase screen sharpness of a display apparatus, a polarizing plate and a display apparatus comprising the same.

Claims

1. An anti-reflective film comprising a low moisture permeable polymer film; a hard coating layer; and a low refractive index layer, wherein the anti-reflective film has a mean of intervals between peaks of 160 to 200 in an azimuthal angle distribution curve calculated from an azimuthal scan of diffraction pattern obtained by transmission mode X-ray diffraction (XRD), at 2 of 17 to 18.

2. The anti-reflective film according to claim 1, wherein the azimuthal angle distribution curve contains at least 3 peaks.

3. The anti-reflective film according to claim 1, wherein the low refractive index layer comprises a binder resin, and inorganic fine particles dispersed in the binder resin.

4. The anti-reflective film according to claim 3, wherein the binder resin comprises (co)polymer of photopolymerizable compounds.

5. The anti-reflective film according to claim 4, wherein the binder resin further comprises a crosslinked polymer of a photopolymeriazble compound, a fluorine-containing compound comprising a photoreactive functional group, and polysilsesquioxane substituted with one or more reactive functional groups.

6. The anti-reflective film according to claim 5, wherein the fluorine-containing compound comprising a photoreactive functional group comprises one or more compounds selected from the group consisting of i) aliphatic compounds or alicyclic compounds substituted with one or more photoreactive functional groups, in which at least one carbon is substituted with one or more fluorine atoms; ii) heteroaliphatic compounds or heteroalicyclic compounds substituted with one or more photoreactive functional groups, in which at least one hydrogen is substituted with fluorine, and at least one carbon is substituted with silicon; iii) polydialkyl siloxane-based polymer substituted with one or more photoreactive functional groups, in which at least one silicon is substituted with one or more fluorine atoms; and iv) polyether compounds substituted with one or more photoreactive functional groups, in which at least one hydrogen is substituted with fluorine.

7. The anti-reflective film according to claim 5, wherein the reactive functional group substituted at polysilsesquioxane includes one or more functional groups selected from the group alcohol, amine, carboxylic acid, epoxide, imide, (meth)acrylate, nitrile, norbornene, olefin, polyethyleneglycol, thiol and vinyl groups.

8. The anti-reflective film according to claim 3, wherein the inorganic fine particles include one or more nanoparticles selected from the group solid inorganic nanoparticles having an average diameter of 0.5 to 100 m, and hollow inorganic nanoparticles having an average diameter of 1 to 200 nm.

9. The anti-reflective film according to claim 1, wherein the hard coating layer comprises a binder resin comprising photocurable resin, and organic or inorganic fine particles dispersed in the binder resin.

10. The anti-reflective film according to claim 9, wherein the binder resin of the hard coating layer further comprises high molecular weight (co)polymer having a number average molecular weight of 10,000 or more.

11. The anti-reflective film according to claim 1, wherein the low moisture permeable polymer film has a thickness direction retardation (Rth) measured at a wavelength of 550 nm, of 5,000 nm or more, and a ratio of a first tensile strength in one direction to a second tensile strength in a direction perpendicular to the one direction, of 2 or more, and the second tensile strength is smaller than the first tensile strength in one direction.

12. The anti-reflective film according to claim 1, wherein the low moisture permeable polymer film is a polyethylene terephthalate film.

13. The anti-reflective film according to claim 1, wherein the anti-reflective film has average reflectance in the wavelength region of 380 nm to 780 nm, of 2.0% or less.

14. The anti-reflective film according to claim 1, wherein the anti-reflective film has an average reflectance deviation of 0.2% p or less, and a light transmittance deviation of 0.2% p or less.

15. A polarizing plate comprising the anti-reflective film according to claim 1, and a polarizer.

16. A display apparatus comprising the anti-reflective film according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0124] FIG. 1 and FIG. 2 show transmission mode diffraction patterns of the anti-reflective film of Example 1.

[0125] FIG. 3 shows the azimuthal angle distribution curve calculated from the anti-reflective film of Example 1.

[0126] FIG. 4 shows the azimuthal angle distribution curve calculated from the anti-reflective film of Comparative Example 1.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0127] The present invention will be explained in detail in the following Examples. However, these examples are presented only as the illustrations of the present invention, and the scope of the present invention is not limited thereby.

Preparation Example 1: Preparation of a Coating Solution for Forming a Hard Coating Layer

[0128] The components described in the following Table 1 were mixed to prepare coating solutions (B1, B2 and B3) for forming a hard coating layer.

TABLE-US-00001 TABLE 1 (unit: g) B1 B2 B3 DPHA 6.237 PETA 16.421 10.728 13.413 UA-306T 3.079 2.069 6.114 8BR-500 6.158 6.537 6.114 IRG-184 1.026 1.023 1.026 Tego-270 0.051 0.051 0.051 BYK350 0.051 0.051 0.051 2-butanol 25.92 32.80 36.10 IPA 45.92 38.80 35.70 XX-103BQ(2.0 m 1.515) 0.318 0.460 0.600 XX-113BQ(2.0 m 1.555) 0.708 0.563 0.300 MA-ST(30% in MeOH) 0.342 0.682 0.542 DPHA: dipentaerythritol hexaacrylate PETA: pentaerythritol triacrylate UA-306T: urethane acrylate, a reaction product of toluene diisocyante and pentaerythritol triacrylate (a product from Kyoeisha) 8BR-500: photocurable urethane acrylate polymer (Mw 200,000, a product from Taisei Fine Chemical) IRG-184: initiator (Irgacure 184, a product from Ciba) Tego-270: leveling agent (a product from Tego) BYK350: leveling agent (a product from BYK) IPA isopropyl alcohol XX-103BQ (diameter: 2.0 m, Refractive index: 1.515): copolymer particles of polystyrene and polymethyl methacrylate (a product from Sekisui Plastic) XX-1136Q(diameter: 2.0 m, Refractive index: 1.555): copolymer particles of polystyrene and polymethyl methacrylate (a product from Sekisui Plastic) MA-ST (30% in MeOH): dispersion in which nanosilica particles having a size of 10~15 nm are dispersed in methyl alcohol (a product from Nissan Chemical)

Preparation Example 2-1: Preparation of a Coating Solution (C1) for Forming a Low Refractive Index Layer

[0129] 100 g of trimethylolpropane triacrylate (TMPTA), 283 g of hollow silica nanoparticles (diameter range: about 42 nm to 66 nm, a product from JSC catalyst and chemicals), 59 g of solid silica nanoparticles (diameter range: about 12 nm to 19 nm), 115 g of a first fluorine-containing compound (X-71-1203M, ShinEtsu), 15.5 g of a second fluorine-containing compound (RS-537, DIC) and 10 g of an initiator (Irgacure 127, Ciba) were diluted in a solvent of MIBK (methyl isobutyl ketone) such that solid content concentration became 3 wt %, thus preparing a coating solution (a photocurable coating composition) for forming a low refractive index layer.

Preparation Example 2-2: Preparation of a Coating Solution (C2) for Forming a Low Refractive Index Layer

[0130] 100 g of dipentaerythritol hexaacrylate (DPHA), 143 g of hollow silica nanoparticles (diameter range: about 51 nm to 72 nm, a product from JSC catalyst and chemicals), 29 g of solid silica nanoparticles (diameter range: about 12 nm to 19 nm), 56 g of a fluorine-containing compound (RS-537, DIC) and 3.1 g of an initiator (Irgacure 127, Ciba Company) were diluted in a solvent of MIBK (methyl isobutyl ketone) such that solid content concentration became 3.5 wt %, thus preparing a coating solution (a photocurable coating composition) for forming a low refractive index layer.

Examples and Comparative Examples: Preparation of Anti-Reflective Films

[0131] On each low moisture permeable polymer film (thickness 80 m) described in the following Table 2, each coating solution (B1, B2, B3) for forming a hard coating layer prepared above was coated with #12 mayer bar, and then, dried at 60 C. for 2 minutes, and UV cured to form a hard coating layer (coating thickness 5 m). As an UV lamp, H bulb was used, and a curing reaction was progressed under nitrogen atmosphere. The quantity of UV irradiated during curing was 100 mJ/cm.sup.2.

[0132] On the hard coating layer, each coating solution (C1, C2) for forming a low refractive index layer was coated with #4 mayer bar to a thickness of about 110 to 120 nm, and dried at 40 C. for 1 minute and cured. During curing, UV was irradiated at 252 mJ/cm.sup.2 to the dried coating solution under nitrogen purging.

TABLE-US-00002 TABLE 2 Anti-reflective film Tensile strength Hard coating Low refractive index ratio* layer layer Example 1 3.9 Coating solution Coating solution (B1) (C1) Example 2 3.6 Coating solution Coating solution (B2) (C1) Example 3 4.2 Coating solution Coating solution (B2) (C1) Example 4 2.5 Coating solution Coating solution (B3) (C1) Example 5 2.3 Coating solution Coating solution (B1) (C2) Comparative 1.0 Coating solution Coating solution Example 1 (B3) (C1) Comparative 1.5 Coating solution Coating solution Example 2 (B2) (C1) Comparative 1.2 Coating solution Coating solution Example 3 (B2) (C1) Comparative 1.9 Coating solution Coating solution Example 4 (B1) (C2) Comparative 1.7 Coating solution Coating solution Example 5 (B1) (C2) *tensile strength ratio: a ratio of tensile strength in one direction having larger value, to tensile strength in a direction perpendicular to the one direction having smaller value, in the low moisture permeable polymer film

[0133] Evaluation

[0134] 1. Evaluation of Transmission Mode X-Ray Diffraction (XRD)

[0135] For the anti-reflective films obtained in Examples and Comparative Examples, 2 cm*2 cm (width*length) samples were prepared, and then, Cu-K rays of 1.54 wavelength were irradiated.

[0136] Specifically, 10 samples were overlapped and fixed in a holder, and positioned on a gomiometer center. The samples were stacked such that one direction having lower tensile strength and a direction perpendicular to the one direction having higher tensile strength in each low moisture polymer film of each sample are the same.

[0137] As the measuring apparatus, Bruker AXS D8 Discover XRD was used, the voltage and current used were respectively 50 kV and 1000 A, and the optics and detector used were as follows. [0138] Primary (incident beam) optics: beam collimator (0.3 mm) [0139] Secondary (diffracted beam) optics: none [0140] VANTEC-500 (2D detector)

[0141] was fixed to 0 and detector was fixed to 24 such that a (010) crystal plane in the low moisture permeable polymer film is measured around 2 =17.6, and then, measurement was conducted at psi 0 to 90 at an interval of 30, 2400 seconds with 4 frame, using 0.33 mm beam collimator. The conversion of X-ray diffraction pattern by the Cu-K rays and the analysis were conducted using DIFFRAC.EVA program of Bruker, and by 2 -integration of the region having 2 of 17.25 to 18.25 using wedge cursor, converted into 1 D-pattern.

[0142] Each pattern measured and converted at each psi position was shifted each 30, 60, and 90 so as to correspond to the practically measured chi value and combined, and the pattern was shifted such that the extreme value in data obtained at Chi 0 is positioned at gamma 0, thus obtaining the azimuthal angle distribution curve.

[0143] In the azimuthal angle distribution curve, the X-axis is gamma (degree) and 0 is a position where a stretching axis is perpendicular to a sample stage, and the Y-axis is integrated intensity of the (010) plane, and intervals between peaks appearing at the azimuthal angle distribution curve were measured and the arithmetic mean was calculated, and the results were shown in the following Table 3.

[0144] Meanwhile, FIG. 1 and FIG. 2 shows transmission mode diffraction pattern of the anti-reflective film of Example 1. Particularly, in FIG. 1 and FIG. 2, the anti-reflective film of Example 1 is rotated 90 and is abraded. FIG. 3 shows the azimuthal angle distribution curve calculated from the anti-reflective film of Example 1, and FIG. 4 shows the azimuthal angle distribution curve calculated from the anti-reflective film of Comparative Example 1.

[0145] 2. Evaluation of Average Reflectance

[0146] The rear side (one side of the low moisture permeable polymer film on which a hard coating layer is not formed) of each anti-reflective film obtained in Examples and Comparative Examples was darkened, and then, average reflectance in the wavelength region of 380 nm to 780 nm was measured using a reflectance mode of Solidspec 3700 (SHIMADZU), and the results were shown in the following Table 3.

[0147] 3. Evaluation of Average Reflectance Deviation

[0148] For each anti-reflective film obtained in Examples and Comparative Examples, 20 points were randomly selected, and for each point, average reflectance was measured by the method of 2. Evaluation of average reflectance. Thereafter, the arithmetic mean of the measured average reflectances of 20 points was calculated. Thereafter, a difference (absolute value) between the average reflectance at each point and the arithmetic mean was defined as average reflectance deviation, and each average reflectance deviation was calculated at each of 20 points. Among the 20 average reflectance deviations, the largest average reflectance deviation was described in the following Table 3.

[0149] 4. Evaluation of Light Transmittance Deviation

[0150] For each anti-reflective film obtained in Examples and Comparative Examples, 20 points were randomly selected, and for each point, light transmittance was measured.

[0151] Specifically, average light transmittance in the wavelength region of 380 to 780 nm was measured using a transmittance mode of Solidspec 3700 (SHIMADZU).

[0152] Thereafter, the arithmetic mean of the measured light transmittances of 20 points was calculated. Thereafter, a difference (absolute value) between the light transmittance at each point and the arithmetic mean was defined as light transmittance deviation, and each light transmittance deviation was calculated at each of 20 points. Among the 20 light transmittance deviations, the largest light transmittance deviation was described in the following Table 3.

[0153] 5. Evaluation of Moisture Permeability

[0154] The moisture permeability of each anti-reflective film obtained in Examples and Comparative Examples was measured at a temperature of 38 C. and relative humidity of 100%, using MOCON test apparatus (PERMATRAN-W, MODEL 3/61).

TABLE-US-00003 TABLE 3 Mean of Average Average Light Moisture intervals reflec- reflectance transmittance perme- between tance deviation deviation ability peaks () (%) (% p) (% p) (g/m.sup.2 .Math. day) Example 1 173 1.05 0.04 0.02 10.61 Example 2 181 1.13 0.11 0.09 11.18 Example 3 195 1.12 0.07 0.08 10.44 Example 4 169 1.07 0.16 0.11 12.21 Example 5 177 1.6 0.03 0.15 11.81 Comparative 103.3 1.13 0.35 0.22 12.35 Example 1 Comparative 79.8 1.04 0.26 0.23 10.54 Example 2 Comparative 46.5 0.99 0.28 0.3 11.38 Example 3 Comparative 50.6 1.55 0.25 0.28 11.25 Example 4 Comparative 52.1 1.5 0.35 0.32 10.91 Example 5

[0155] From the Table 3, it was confirmed that Examples 1 to 4 fulfill intervals between peaks of 160 to 200, and have remarkably low average reflectance deviation and light transmittance deviation, compared to Comparative Examples 1 to 4.