Anti-fingerprint film and electrical and electronic apparatus

1. An anti-fingerprint film comprising:

a flat film; and

two or more nanoscale or microscale microprojections formed on the flat film, wherein the two or more nanoscale or microscale microprojections include two neighboring microprojections,

wherein each microprojection has a contact side contacting the flat film, an upper side facing the contact side, and a side wall connecting the contact side and the upper side,

wherein the nanoscale or microscale microprojections have a shape such that an internal angle formed by the side wall and the contact side is an obtuse angle,

wherein a ratio (D/P) of a longest diameter (D) of the upper side of one of the microprojections to a sum (P) of the distance between the upper sides of the two neighboring microprojections and the longest diameter of the upper side of one of the microprojections is 0.28 to 0.48, and

wherein the anti-fingerprint film has an interaction energy (K A ) as defined by General Formula 1 in a range of 3 mJ/m 2 or less:

K

A

=

[

{

ρ

⁡

(

2

-

3

⁢

cos

⁢

⁢

θ

′

+

cos

3

⁢

θ

′

)

3

}

1

/

3

]

⁢

g

2

⁢

(

1

+

cos

⁢

⁢

θ

′

)

(

1

+

cos

⁢

⁢

θ

)

⁢

(

m

π

)

2

/

3

⁢

sin

⁢

⁢

α

sin

⁢

⁢

θ

′

[

General

⁢

⁢

Formula

⁢

⁢

1

]

wherein, in General Formula 1,

α is a sliding angle of a liquid put on the anti-fingerprint film,

θ′ is a contact angle formed by the anti-fingerprint film and the liquid,

θ is a contact angle formed by the flat film and the liquid,

ρ is the density of the liquid, m is the mass of the liquid, and g is gravitational acceleration.

2. The anti-fingerprint film according to claim 1 ,

wherein the interaction energy (K A ) is 0.5 mJ/m 2 to 2.0 mJ/m 2 .

3. The anti-fingerprint film according to claim 1 ,

wherein the anti-fingerprint film has the sliding angle (α) to 30 μl of oleic acid of 20° or less.

4. The anti-fingerprint film according to claim 1 ,

wherein the anti-fingerprint film has the contact angle (θ′) of 120° or more to 3 μl of oleic acid and to 3 μl of distilled water.

5. The anti-fingerprint film according to claim 1 ,

wherein the height of the microprojections is 0.1 μm to 40 μm.

6. The anti-fingerprint film according to claim 1 ,

wherein the longest diameter of the upper side of the microprojections is 0.2 μm to 100 μm.

7. The anti-fingerprint film according to claim 1 ,

wherein the internal angle formed by the side wall and the contact side is 100° to 170°.

8. The anti-fingerprint film according to claim 1 ,

wherein the upper side is connected to the side wall while forming a curved surface therewith, and

a ratio (r/D) of the internal radius of curvature (r) of the curved surface at which the side wall and the upper side are connected to the longest diameter (D) of the upper side of the microprojection is 0.1 or less.

9. The anti-fingerprint film according to claim 1 ,

wherein the microprojections include at least one selected from the group consisting of glass, silicon, silicon doped with a metal, polysilicon, a silicon-based polymer, a metal, a urethane resin, a polyimide resin, a polyester resin, a (meth)acrylate-based polymer resin, a polyolefin resin, and a photosensitive polymer resin.

10. The anti-fingerprint film according to claim 1 ,

further comprising a fluorine-based compound layer stacked on the outside of the microprojections,

wherein the fluorine-based compound layer has a thickness of 5 nm to 5 μm.

11. The anti-fingerprint film according to claim 10 ,

wherein the fluorine-based compound layer comprises a fluorine-based unimolecular compound, a fluorine-based polymer compound, or a mixture thereof.

12. An electrical and electronic apparatus comprising the anti-fingerprint film of claim 1 .