Optical article coated with an antireflection coating comprising a sub-layer partially formed under ion assistance and its manufacturing process
The invention relates to an optical article provided with antireflection properties, comprising a substrate having at least one main surface coated with an antireflection coating comprising, starting from the substrate: a sub-layer comprising two adjacent layers formed from the same material, the sum of the thicknesses of the two adjacent layers being greater than or equal to 75 nm; and a multilayered antireflection stack comprising at least one high refractive index layer and at least one low refractive index layer, the deposition of the first of said two adjacent layers of the sub-layer having been carried out without ion assistance and the deposition of the second of said two adjacent layers of the sub-layer having been carried out under ion assistance. The invention also relates to a process for manufacturing such an optical article.
1. An optical article with antireflection properties, comprising a substrate having at least one main surface coated with an antireflection coating comprising, starting from the substrate:
a sub-layer comprising two adjacent layers, the sum of the thicknesses of the two adjacent layers being greater than or equal to 75 nm; and
multilayered antireflection stack comprising at least one high refractive index layer and at least one low refractive index layer,
wherein the second adjacent layer of the sub-layer is directly deposited upon the first adjacent layer of the sub-layer,
wherein the deposition of the first adjacent layer of the sub-layer has been carried out without ion assistance and the deposition of the second adjacent layer of the sub-layer has been carried out under ion assistance, and
wherein the sub-layer is deposited on an abrasion- and/or scratch-resistant coating.
2. The article of claim 1 , wherein the two adjacent layers of the sub-layer are formed from the same material.
3. The article of claim 1 , wherein the thickness ratio of the sub-layer two adjacent layers to each other varies from 9:1 to 1:9.
4. The article of claim 3 , wherein the thickness ratio of the sub-layer two adjacent layers to each other varies from 4:6 to 6:4.
5. The article of claim 1 , wherein the sum of the thicknesses of the two adjacent layers is greater than or equal to 80 nm.
6. The article of claim 5 , wherein the sum of the thicknesses of the two adjacent layers is greater than or equal to 100 nm.
7. The article of claim 6 , wherein the sum of the thicknesses of the two adjacent layers is greater than or equal to 150 nm.
8. The article of claim 1 , wherein the sub-layer two adjacent layers are SiO 2 -based layers.
9. The article of claim 8 , wherein the sub-layer two adjacent layers are free of Al 2 O 3 .
10. The article of claim 8 , wherein the sub-layer consists of SiO 2 layers.
11. The article of claim 1 , wherein the sub-layer comprises, in addition to the two adjacent layers, from one to three layers interleaved between the substrate and the first adjacent layer of the sub-layer.
12. The article of claim 1 , further defined as comprising an ASTM BAYER value greater than or equal to 4.5 of the standard ASTM F 735.81.
13. The article of claim 1 , wherein all the low refractive index layers of the multilayered antireflection stack comprise a mixture of SiO 2 and Al 2 O 3 .
14. The article of claim 1 , wherein the abrasion- and/or scratch-resistant coating is a poly(meth)acrylate or an epoxysilane based coating.
15. The article of claim 1 , wherein the high refractive index layers of the multilayered stack comprise at least one of TiO 2 , PrTiO 3 , or ZrO 2 , or combinations thereof.
16. The article of claim 1 , further defined as an ophthalmic lens.
17. The article of claim 1 , wherein the sub-layer is adjacent to a high refractive index layer of said multilayered antireflection stack.
18. The article of claim 1 , wherein the sum of the thicknesses of said two adjacent layers of the sub-layer is lower than 250 nm.
19. The article of claim 1 , wherein the sub-layer comprises a higher layer and a lower layer adjacent to each other, the sum of the thicknesses of said two adjacent layers being greater than or equal to 75 nm, said higher layer being an SiO2-based layer.
20. The article of claim 1 , wherein the thickness of the abrasion and/or scratch-resistant coating ranges from 2 to 10 μm.