Antireflection film having silver-containing layer and fluorocarbon layer, method for producing antireflection film, optical element, and optical system

1. An antireflection film that is provided on a substrate and is formed by laminating an interlayer, a silver-containing metal layer containing silver, and a dielectric layer, in this order, on the substrate,

wherein the interlayer is a multilayer film having two or more layers, in which a layer of high refractive index having a relatively high refractive index and a layer of low refractive index having a relatively low refractive index are alternately laminated,

wherein the dielectric layer has a surface to be exposed to air and is a multilayer film having two or more layers including an oxide layer and a fluorocarbon layer, which is a self-assembled film that is formed by a silane coupling reaction to the oxide layer,

wherein the dielectric layer includes a silicon oxide layer, and a layer having a refractive index lower than a refractive index of the silicon oxide layer, and

wherein the layer having a refractive index lower than a refractive index of the silicon oxide layer is provided nearer to the silver-containing metal layer than the oxide layer.

2. The antireflection film according to claim 1 ,

wherein the oxide layer is the silicon oxide layer.

3. The antireflection film according to claim 1 ,

wherein the layer having a refractive index lower than the refractive index of the silicon oxide layer is a magnesium fluoride layer.

4. The antireflection film according to claim 3 ,

wherein the magnesium fluoride layer is arranged closer to the silver-containing metal layer than the silicon oxide layer.

5. The antireflection film according to claim 1 ,

wherein the surface to be exposed to air of the dielectric layer is formed of a fluorocarbon layer.

6. The antireflection film according to claim 1 ,

wherein a thickness of the fluorocarbon layer is 20 nm or less.

7. The antireflection film according to claim 1 ,

wherein a thickness of the silver-containing metal layer is 6 nm or less.

8. The antireflection film according to claim 1 , further comprising:

an anchor layer provided between the silver-containing metal layer and the interlayer.

9. The antireflection film according to claim 1 , further comprising:

an anchor region including an oxide of an anchor metal provided between the silver-containing metal layer and the interlayer; and

a cap region including an oxide of the anchor metal provided between the silver-containing metal layer and the dielectric layer.

10. A method for producing the antireflection film according to claim 1 , the method comprising:

sequentially laminating the interlayer and the silver-containing metal layer on one surface of the substrate by a vapor phase growth method; and

laminating the oxide layer on the silver-containing metal layer by a vapor phase growth method, and then immersing at least a surface of the oxide layer in a solution including a silane coupling agent having a fluorocarbon group to form the fluorocarbon layer by self-organization through a silane coupling reaction to the surface of the oxide layer.

11. An optical element comprising:

the antireflection film according to claim 1 .

12. An optical system comprising:

a group lens, which includes the optical element according to claim 11 , and in which a surface of the optical element having the antireflection film provided thereon is arranged on outermost surfaces.