ANTI-GLARE FILM AND DISPLAY APPARATUS

Abstract

[Summary]

The present invention relates to an anti-glare film and a display apparatus, and more particularly to an anti-glare film including: a light-transmitting substrate; and a hard coating layer containing a binder resin, organic fine particles and inorganic fine particles dispersed in the binder resin, wherein a ratio of two or more organic fine particles aggregating with each other in the whole organic fine particles is 5% or less, and wherein a ratio of internal haze to external haze is 2.5 or less, and a display apparatus including the anti-glare film.

Claims

1. An anti-glare film comprising: a light-transmitting substrate; and a hard coating layer containing a binder resin, organic fine particles and inorganic fine particles wherein the organic fine particles and the inorganic fine particles are dispersed in the binder resin, wherein a ratio of two or more organic fine particles aggregating with each other in the total organic fine particles is 5% or less, and wherein the anti-glare film has a ratio of internal haze to external haze of 2.5 or less.

2. The anti-glare film according to claim 1, wherein two adjacent organic fine particles among the two or more organic fine particles aggregating with each other are located at different distances from one surface of the hard coating layer.

3. The anti-glare film according to claim 1, wherein two adjacent organic fine particles among the two or more organic fine particles aggregating with each other have a focus on respective optical microscopes at different positions with respect to a thickness direction on the basis of one surface of the hard coating layer.

4. The anti-glare film according to claim 1, wherein two adjacent organic fine particles among the two or more organic fine particles aggregating with each other are located with a distance difference of at least 0.1 M from one surface of the hard coating layer.

5. The anti-glare film according to claim 1, wherein the ratio of the internal haze to the external haze is 0.8 to 1.8.

6. The anti-glare film according to claim 1, wherein the hard coating layer has a thickness of 1 to 10 m.

7. The anti-glare film according to claim 1, wherein the organic fine particles have a diameter of 0.5 m to 6 m and a refractive index of 1.500 to 1.600 at a wavelength of 550 nm.

8. The anti-glare film according to claim 1, wherein the inorganic fine particles have a diameter of 0.01 m to 5 m.

9. The anti-glare film according to claim 1, wherein the binder resin includes a polymer or copolymer of a vinyl-based monomer or a (meth)acrylate-based monomer.

10. The anti-glare film according to claim 1, wherein the hard coating layer contains 5 to 25 parts by weight of the organic fine particles based on 100 parts by weight of the binder resin.

11. The anti-glare film according to claim 1, wherein the light-transmitting substrate has a thickness direction retardation (Rth) of at least 3,000 nm as measured at a wavelength of 400 nm to 800 nm.

12. A display apparatus comprising the anti-glare film according to claim 1.

13. The display apparatus according to claim 12, wherein the display apparatus is a notebook display device, and the anti-glare film is located on an outermost surface of the notebook display device.

14. The anti-glare film according to claim 2, wherein two adjacent organic fine particles among the two or more organic fine particles aggregating with each other have a focus on respective optical microscopes at different positions with respect to a thickness direction on the basis of one surface of the hard coating layer.

15. The anti-glare film according to claim 2, wherein two adjacent organic fine particles among the two or more organic fine particles aggregating with each other are located with a distance difference of at least 0.1 m from one surface of the hard coating layer.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0084] FIG. 1 shows an optical microscope photograph of a plane of the hard coating layer obtained in Example 1.

[0085] FIG. 2 shows an optical microscope photograph of a plane of the hard coating layer obtained in Comparative Example 3.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0086] The present invention will be described in more detail with reference to the following examples. However, these examples are given for illustrative purposes only, and the scope of the invention is not intended to be limited to or by these examples.

Example and Comparative Example: Preparation of Anti-Glare Film

[0087] (1) Preparation of Composition for Forming Hard Coating Layer

[0088] A monomer, a polymer and a solvent for forming the binder resin shown in Table 1 below were uniformly mixed to prepare a first coating solution, and organic fine particles and inorganic fine particles were mixed with a particle-diluting solvent to prepare a second coating solution.

[0089] After sufficiently stirring each coating solution to be uniformly mixed, the two coating solutions were mixed to produce a hard coating composition.

[0090] (2) Preparation of Anti-Glare Film

[0091] The hard coating composition thus obtained was coated onto a substrate of Table 2 below with a #10 mayer bar and dried at 90 C. for 1 minute.

[0092] The dried product was irradiated with ultraviolet light of 150 mJ/cm.sup.2 to form a hard coating layer, thereby preparing an anti-glare film.

TABLE-US-00001 TABLE 1 (content: g) Com- Com- Com- Com- parative parative parative parative Example Example Example Example Example Example Example 1 2 3 1 2 3 4 First Binder PETA 13.854 14.200 14.200 13.828 13.828 13.828 13.854 coating EB-1290 13.854 14.200 14.200 13.828 13.828 13.828 13.854 solution Initiator I184 2.102 2.158 2.158 2.098 2.098 2.098 2.102 Additive T270 0.200 0.204 0.204 0.200 0.200 0.200 0.200 F477 0.100 0.117 0.117 0.100 0.100 0.100 0.100 Solvent MIBK 40.281 41.297 41.297 20.102 40.204 40.204 Ethanol 20.102 40.281 Second Particle- n-BA 20.141 20.648 20.648 20.102 20.102 20.102 20.141 coating diluting solution solution Inorganic MA- 6.264 3.759 6.835 6.428 6.428 6.428 6.264 fine ST (30% particles in MeOH) Organic Addition 3.203 3.417 3.417 3.214 3.214 3.214 3.203 fine amount (3.5 um/ (3.5 um/ (3.5 um/ (2 um/ (3.5 um/ (2 um/ (3.5 um/ particles (size/re- 1.555) 1.555) 1.555) 1.555) 1.595) 1.595) 1.555) fractive index) Type of 68BQ 68BQ 68BQ 67BQ 90BQ 112BQ 68BQ particle *PETA: Pentaerythritol triacrylate, SK Entis product MA-ST: dispersion solution in which spherical silica fine particles having a volume average particle size of 12 nm and a refractive index of 1.43 (manufactured by Nissan Chemical) is dispersed in methanol at a concentration of 30% MIBK: methyl isobutyl ketone Ethanol: ethanol n-BA: normal butyl acetate EB-1290: photocurable aliphatic urethane hexaacrylate/SK Entis/solid content 100% I184: photocuring initiator (Irgacure 184, manufactured by BASF) T270: leveling additive having a solid content of 100% (Tego-Glide 270, manufactured by Tego Evonik) F477: fluorine leveling additive having a solid content of 100% (F477, manufactured by DIC Chemical) 68BQ (XX-68BQ, manufactured by Sekisui Plastic): polystyrene-polymethylmethacrylate crosslinked copolymer fine particles having a refractive index of 1.555 and an average particle diameter of 3.5 m 67BQ (XX-67BQ, manufactured by Sekisui Plastic): polystyrene-polymethylmethacrylate crosslinked copolymer fine particles having a refractive index of 1.555 and an average particle diameter of 2.0 m 90BQ (XX-90BQ, manufactured by Sekisui Plastic): polystyrene-polymethylmethacrylate crosslinked copolymer fine particles having a refractive index of 1.595 and an average particle diameter of 3.5 m 112BQ (XX-112BQ, manufactured by Sekisui Plastic): polystyrene-polymethylmethacrylate crosslinked copolymer fine particles having a refractive index of 1.595 and an average particle diameter of 2 m.

TABLE-US-00002 TABLE 2 Example Example Example Comparative Comparative Comparative Comparative 1 2 3 Example 1 Example 2 Example 3 Example 4 Substrate SRF PET SRF PET SRF PET SRF PET SRF PET SRF PET SRF PET (Retardation nm) (>5000) (>5000) (>5000) (>5000) (>5000) (>5000) (>5000) *SRF PET: Super Retarder Film PolyEthylene Terephthalate

Experimental Example

[0093] 1. Confirmation of the Ratio of Organic Fine Particles Aggregating in the Hard Coating Layer

[0094] With respect to the hard coating layer obtained in each of Examples and Comparative Examples, a transmission image was taken with an optical microscope (Oxmpus BX51 optical microscope) to confirm the ratio of organic fine particles which aggregate with each other.

[0095] In detail, the film was placed so that the hard coating layer faces on the objective lens side, and the transmission image was observed by setting the microscope to 10 eyepiece lens and 10 or 20 objective lens.

[0096] When there was a difference in distance of about 0.5 m or more in the thickness direction on the basis of one surface of the hard coating layer, it was judged that the organic fine particles were aggregated with each other.

[0097] When observing the overlapping particle site, the cross section of the particle located at the bottom was focused to confirm the overlap of the particles located at the top.

[0098] At this time, when the upper particles were not overlapped in the thickness direction, the overlapping portions of the two particles must not be confirmed.

[0099] Meanwhile, when the two particles were overlapped in the thickness direction, the lower particles that were in focus did not look like a sharp spherical shape, and it was observed in the form that a part was hidden by the upper particle.

[0100] After confirming the number of overlapped particles in this manner, the ratio of overlapped particles was calculated by dividing it by the number of total particles on the same measurement surface.

[0101] 2. Evaluation of Light Transmittance and Total/Internal/External Haze

[0102] A specimen with a size of 4 cm4 cm was prepared from the anti-glare film obtained in each of Examples and Comparative Examples, and the average value was measured three times with a haze meter (HM-150, A light source, Murakami Color Research Laboratory), which was calculated as a total haze value.

[0103] In the measurement, the transmittance and the haze value were measured at the same time. The light transmittance was measured according to JIS K 7361, and the haze value was measured according to JIS K 7105.

[0104] In measuring the internal haze value, an adhesive film having a total haze value of 0 was bonded to the coated surface of the optical film to be measured to make the unevenness of the surface smooth, and then an internal haze value was measured in the same manner as that of the total haze value.

[0105] The external haze value was calculated as the average of the values obtained by calculating the difference between the total haze value and the measured value of the internal haze.

[0106] 3. Confirmation of Occurrence of Rainbow

[0107] A specimen with a size of 10 cm10 cm was prepared from the anti-glare film obtained in each of Examples and Comparative Examples, and a black film (UTS-30BAF film, manufactured by Nitto) was adhered to the opposite surface of the hard coating layer using a lamination process.

[0108] After allowing a light of a three-wavelength lamp to reflect on the hard-coated surface of the film, it was confirmed whether or not the rainbow of the reflected image was occurred.

[0109] <Measure Standard>

[0110] X: Rainbow is not visible

[0111] Medium: Rainbow is weakly visible. The difference in average wavelength between colors that form a rainbow, such as green-blue, blue-purple, etc. is 80 nm or less.

[0112] Strong: Rainbow is strongly visible. Colors forming a rainbow such as red-green, orange-blue, etc. have complementary color relation to each other, or mean wavelength difference is more than 100 nm.

[0113] 4. Confirmation of Occurrence of Sparkling

[0114] A sample with a size of 12 cm12 cm was prepared from the anti-glare film obtained in each of Examples and Comparative Examples, and the sample was placed so that the hard coating surface faces upward on the 150 PPI panel.

[0115] At this time, tape may be adhered to the slope so that the film is not floated.

[0116] After that, the panel was driven so that a white screen could be seen, and it was then confirmed whether or not sparkling occurred in an area within 10 cm10 cm of the sample.

[0117] <Measure Standard>

[0118] Excellent: Sparkling occurs

[0119] Defective: No sparking occurs

[0120] 6. Measurement of Image Definition (%)

[0121] The anti-glare film obtained in each of Examples and Comparative Examples was measured for image definition using ICM-1T (manufactured by Suga Test Instrument Co., Ltd.).

[0122] The image definition was measured in slit widths of 0.125 mm, 0.5 mm, 1 mm, and 2 mm, and expressed as a sum.

TABLE-US-00003 TABLE 3 Comparative Comparative Comparative Comparative Example Example Example Example Example Example Example Category 1 2 3 1 2 3 4 Thickness of hard 4.8 5.5 5 5.5 5.1 4.7 4.8 coating layer Transmittance 92.5 92.5 93.4 91.3 92.5 93 92.5 Internal haze(hi) 11.5 13.6 12.6 7.9 30.5 20.8 11.5 External haze 9.2 9.3 9.8 13.8 9.1 8.3 9.2 (Hs) hi/Hs 1.3 1.5 1.3 0.6 3.4 2.5 1.3 Rainbow X X X Medium X X X Sparkling Excellent Excellent Excellent Defective Excellent Defective Defective Image definition 153.1 155.5 152.3 224 79.1 121.3 125.5 Particle 4.08 3.8 2.0 >5 1.6 7.65 >5 aggregation rate

[0123] As can be seen in Table 3 above, in the case of the anti-glare films of Examples in which the ratio of the organic fine particles aggregating in the whole organic fine particles was 5% or less and the ratio of the internal haze to the external haze was 2.5 or less, it was confirmed that the rainbow phenomenon and the sparkling phenomenon were not occurred and excellent image definition could be realized.

[0124] In contrast, in the case of the anti-glare films of Comparative Examples 1, 2, and 4 in which the ratio of the organic fine particles aggregating in the whole organic fine particles exceeded 5%, it was confirmed that sparkling phenomenon occurred excessively, rainbow phenomenon occurred or image definition appeared to be low. Further, in the case of the anti-glare film of Comparative Example 2 in which the ratio of the organic fine particles aggregating in the whole organic fine particles was 1.6% but the ratio of the internal haze to the external haze was 3.4, sparkling phenomenon was occurred and low image definition was shown.