Optical element

1. An optical element comprising:

a substrate having a silicone surface;

an antireflection layer overlying the silicone surface, wherein the antireflection layer comprises a first organic layer having a reflection-reducing nanostructure, the nanostructure having a depth of at least 30 nm; and

a cover layer overlying the first organic layer, the cover layer having a thickness of no more than 40 nm.

2. The optical element according to claim 1 , further comprising an adhesion layer between the silicone surface and the first organic layer.

3. The optical element according to claim 2 , wherein the adhesion layer comprises a silicon oxide.

4. The optical element according to claim 2 , wherein the adhesion layer has a thickness of no more than 50 nm.

5. The optical element according to claim 1 , wherein the first organic layer comprises a material selected from the group consisting of:

melamine (2,4,6-triamino-1,3,5-triazine),

MBP (5,5′-di(4-biphenylyl)-2,2′-bithiophene),

TPD (N,N′-bis(3-methylphenyl)-N,N′-diphenyl-benzidine),

NPB (N,N-di(naphth-1-yl)-N,N′-diphenyl-benzidine),

TPB (N,N,N′,N′-tetraphenylbenzidine),

TCTA (tris(4-carbazoyl-9-ylphenyl)amine),

B2TP (5,5′-di-(4-byphenylyl)-2,2′-bithiophene) and

parylene.

6. The optical element according to claim 1 , further comprising a second organic layer disposed between the first organic layer and the cover layer, wherein the second organic layer comprises a second nanostructure.

7. The optical element according to claim 6 , wherein the second organic layer has a lower effective refractive index than the first organic layer.

8. The optical element according to claim 6 , wherein the first organic layer and the second organic layer respectively have a refractive index gradient, the refractive index gradient decreasing in a direction extending away from the silicone surface.