Antireflection film, polarizing plate, method for producing them, liquid crystal display element, liquid crystal display device, and image display device

1. An antireflection film comprising:

a transparent support; and

a low-refractive index layer having a lower refractive index than the transparent support, wherein the low-refractive index layer is an outermost layer of the antireflection film, and the low-refractive index layer comprises: a hollow silica particle; and a compound lowering a surface free energy of the antireflection film,

wherein a silicone is segregated at an outer surface of the low-refractive index layer such that a spectral intensity ratio Si/C in a photoelectron spectrum at the outer surface is larger by at least 5 times than that at a depth from the outer surface, the depth being equal to 80% of a thickness of the low-refractive index layer,

wherein the compound is a silicone compound having a plurality of (meth)acryloyl groups at a terminal or a side chain of a compound chain that contains a plurality of dimethylsilyloxy units as repetitive units, and having a molecular weight of from 3,000 to 30,000,

wherein the low-refractive index layer comprises a binder, and the compound comprises a reactive group with the binder,

wherein the binder consists of a (co)polymer of at least one monomer having two or more ethylenic unsaturated groups, wherein the monomer having two or more ethylenic unsaturated groups consists of ethylene glycol di(meth)acrylate, 1,4-cyclohexane diacrylate, pentaerythritol tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,2,3-cyclohexane tetramethacrylate, polyurethane polyacrylate, polyester polyacrylate, or a combination thereof,

wherein the hollow silica particle has a porosity x of from 10 to 60%, the porosity being represented by the following formula (V):

x =(4 πa 3 /3)/(4 πb 3 /3)×100  (V)

wherein a represents a radius of a hollow of the particle and b represents a radius of an outer shell of the particle.

2. A polarizing plate comprising the antireflection film of claim 1 .

3. A polarizing plate comprising:

a polarizing sheet; and

a transparent protective film on one side of the polarizing sheet, the transparent protective film comprising an antireflection film of claim 1 .

4. A method for producing a polarizing plate, which comprises: feeding a polymer film for a polarizing sheet; holding each edge of the polymer film with a holding unit; and stretching the polymer film by imparting a tension to the polymer film while moving the holding unit in a machine direction of the polymer film wherein the stretching is performed under a condition satisfying formula (III):

| L 2 −L 1|>0.4 W

wherein L1 indicates a locus of the first holding unit from a substantial holding start point to a substantial holding release point on one edge of the polymer film; L2 indicates a locus of the second holding unit from a substantial holding start point to a substantial holding release point on the other edge of the polymer film; and W indicates a distance between two substantial holding release points of the first holding unit and the second holding unit, and a speed difference of the moving between the first holding unit and the second holding unit is less than 1%, forming a polarizing plate comprising the anti reflection film of claim 1 .

5. The method for producing a polarizing plate as claimed in claim 4 , wherein the stretching is performed under keeping a volatile content of the polymer film at least 5% by volume, and the volatile content is decreased while the polymer film is shrunk.

6. The method for producing a polarizing plate as claimed in claim 4 , which comprises sticking a transparent protective film to one side of the polarizing sheet, the protective film having the antireflection film.

7. An image display comprising the antireflection film of claim 1 .

8. The image display device as claimed in claim 7 , which is a liquid crystal display device.

9. The image display device as claimed in claim 7 , which is a transmissive, reflective or semi-transmissive liquid crystal display of any mode of TN, STN, IPS, VA or OCB.

10. The antireflection film as claimed in claim 1 , wherein the porosity x represented by the formula (V) is from 20 to 60%.

11. The antireflection film as claimed in claim 1 , wherein the porosity x represented by the formula (V) is from 30 to 60%.

12. The antireflection film as claimed in claim 1 , wherein the particle has a refractive index of from 1.17 to 1.40.

13. The antireflection film as claimed in claim 1 , wherein the particle has a refractive index of from 1.17 to 1.35.

14. The antireflection film as claimed in claim 1 , wherein the particle has a refractive index of from 1.17 to 1.30.