Antireflection film and method for preparing same

1. An antireflection film comprising:

a hard coating layer or an antiglare layer; and

a low refractive index layer formed on one side of the hard coating layer or the antiglare layer and including a binder resin, and hollow silica nanoparticles, metal oxide nanoparticles, and inorganic nanoparticles dispersed in the binder resin,

wherein a first region containing the hollow silica nanoparticles, a second region containing the metal oxide nanoparticles, and a third region containing the inorganic nanoparticles are present in the low reflective index layer,

the first region, the second region, and the third region satisfy the following Equation 1:

Refractive Index ( n 1) of First Region<Refractive Index ( n 3) of Third Region<Refractive Index ( n 2) of Second Region  [Equation 1]

wherein n1, n2, and n3 are refractive indexes obtained by carrying out Ellipsometry measurement at an incident angle of 70° over a wavelength range of 380 nm to 1000 nm, and

wherein average diameters of the hollow silica nanoparticle, the metal oxide nanoparticle, and the inorganic nanoparticle satisfy the following Equation 2:

Average Diameter of Inorganic Nanoparticles<Average Diameter of Metal Oxide Nanoparticles<Average Diameter of Hollow Silica Nanoparticles  [Equation 2].

2. The antireflection film of claim 1 , wherein

the first region includes 70% by volume or more of the entire hollow silica nanoparticles, the second region includes 70% by volume or more of the entire metal oxide nanoparticles, and the third region includes 70% by volume or more of the entire inorganic nanoparticles.

3. The antireflection film of claim 1 , wherein in the low refractive index layer, the third region is located closer to the interface between the hard coating layer or the antiglare layer and the low refractive index layer, compared to the second region, and the second region is located closer to the interface between the hard coating layer or the antiglare layer and the low refractive layer, compared to the first region.

4. The antireflection film of claim 1 , wherein

the first region, the second region, and the third region in the low refractive index layer are present in a continuous phase by one binder resin.

5. The antireflection film of claim 1 , wherein

the low refractive index layer is obtained by coating with a resin composition comprising a binder resin, a hollow silica nanoparticle, a metal oxide nanoparticle, and an inorganic nanoparticle.

6. The antireflection film of claim 1 , wherein

a ratio of the average diameter of the inorganic nanoparticles to the average diameter of the metal oxide nanoparticles is 0.5 to 0.9.

7. The antireflection film of claim 1 , wherein

a ratio of the average diameter of the inorganic nanoparticles to the average diameter of the hollow silica nanoparticles is 0.01 to 0.5.

8. The antireflection film of claim 1 , wherein

the refractive index of the first region is less than 1.4, the refractive index of the second region is more than 1.55, and the refractive index of the third region is more than 1.4 and less than 1.55.

9. The antireflection film of claim 1 , wherein

thicknesses of the first region, the second region, and the third region are respectively 10 nm to 200 nm.

10. The antireflection film of claim 1 , wherein

each of the inorganic nanoparticles, the metal oxide nanoparticles, and the hollow silica nanoparticles has on the surface thereof at least one reactive functional group selected from the group consisting of a (meth)acrylate group, an epoxide group, a vinyl group, and a thiol group.

11. The antireflection film of claim 1 , wherein

the inorganic nanoparticles include solid-type silica nanoparticles or antimony-doped tin oxide nanoparticles.

12. The antireflection film of claim 1 , wherein

the antireflection film exhibits an average reflectivity of 0.3% or less in the visible light wavelength band of 380 nm to 780 nm.

13. The antireflection film of claim 1 , wherein

the binder resin contained in the low refractive index layer includes a crosslinked (co)polymer between a (co)polymer of a photopolymerizable compound and a fluorine-containing compound containing a photoreactive functional group.

14. The antireflection film of claim 13 , wherein

the binder resin includes 20 parts by weight to 300 parts by weight of the fluorine-containing compound containing a photoreactive functional group based on 100 parts by weight of the (co)polymer of a photopolymerizable compound.

15. A method for preparing an antireflection film, comprising steps of:

coating a resin composition for forming a low refractive index layer containing a photocurable compound or its (co)polymer, a fluorine-containing compound containing a photoreactive functional group, a photoinitiator, hollow silica nanoparticles, metal oxide nanoparticles, and inorganic nanoparticles on a hard coating layer or an antiglare layer, and drying the coated product at a temperature of 35° C. to 100° C.; and

photocuring the dried product of the resin composition,

wherein an average diameter of the hollow silica nanoparticles, the metal oxide nanoparticles, and the inorganic nanoparticles satisfy the following Equation 2:

Average Diameter of Inorganic Nanoparticles<Average Diameter of Metal Oxide Nanoparticles<Average Diameter of Hollow Silica Nanoparticles  [Equation 2].

16. The method for preparing an antireflection film of claim 15 , wherein

the step of drying the resin composition for forming a low refractive index layer coated on the hard coating layer or the antiglare layer at a temperature of 35° C. to 100° C. is carried out for 10 seconds to 5 minutes.

17. The method for preparing an antireflection film of claim 15 , wherein

a ratio of the average diameter of the inorganic nanoparticles to the average diameter of the metal oxide nanoparticles is 0.5 to 0.9.

18. The method for preparing an antireflection film of claim 15 , wherein

a ratio of the average diameter of the inorganic nanoparticles to the average diameter of the hollow silica nanoparticles is 0.01 to 0.5.