Optical article comprising an antireflective coating with a low reflection both in the ultraviolet region and in the visible region
View Patent ↗This invention relates to an ophthalmic lens with a low reflection both in the ultraviolet region and in the visible region, comprising a substrate provided on its rear main face with a multilayered antireflective coating (3-7 layers) comprising a stack of at least one layer with a high refractive index and at least one layer with a low refractive index, having a mean reflection factor on the rear face in the visible region R m lower than or equal to 1.15%, a mean light reflection factor on the rear face in the visible region R v lower than or equal to 1%, a mean reflection factor R UV on the rear face between 280 nm and 380 nm, weighted by the function W(λ) defined in the ISO 13666:1998 standard, lower than 5%, for angles of incidence of 30° and 45°, the antireflective coating outer layer being a silica-based layer. The lens according to the invention does especially prevent the reflection of the UV radiation produced by light sources located behind the wearer.
1. An ophthalmic lens comprising a substrate with a front main face and a rear main face, the rear main face being coated with a multilayered antireflective coating comprising a stack of at least one layer having a refractive index higher than 1.6 and of at least one layer having a refractive index lower than 1.5 wherein:
the mean reflection factor on the rear face in the visible region R m is lower than or equal to 1.15%;
the mean light reflection factor on the rear face in the visible region R v is lower than or equal to 1%;
the mean reflection factor R UV on the rear face between 280 nm and 380 nm, weighted by the function W(λ) defined in the ISO 13666:1998 standard, is lower than 5%, for an angle of incidence of 30° and for an angle of incidence of 45°;
the multilayered antireflective coating comprises at least 3 layers;
the multilayered antireflective coating does not comprise any layer with a thickness higher than or equal to 20 nm based on indium oxide; and
the antireflective coating outer layer is a silica-based layer,
wherein the antireflective coating comprises, in the direction moving away from the substrate, a layer having a refractive index higher than 1.6 with a thickness of from 20 to 65 nm, a layer having a refractive index lower than 1.5 with a thickness of from 10 to 30 nm, a layer having a refractive index higher than 1.6 with a thickness of from 5 to 75 nm, a layer having a refractive index having higher than 1.6 with a thickness of from 20 to 75, a layer having a refractive index lower than 1.5 with a thickness of from 60 to 85 nm.
2. The lens of claim 1 , wherein the multilayered antireflective coating does not comprise any MgF 2 layer.
3. The lens of claim 1 , wherein the multilayered antireflective coating comprises 7 or fewer layers.
4. The lens of claim 1 , wherein the multilayered antireflective coating comprises 6 layers.
5. The lens of claim 1 , wherein the multilayered antireflective coating comprises 5 or fewer layers.
6. The lens according to claim 1 , wherein the multilayered antireflective coating comprises at least one electrically conductive layer.
7. The lens according to claim 1 , wherein the layer having a refractive index lower than 1.5 is made of silica.
8. The lens according to claim 1 , wherein the layer having a refractive index higher than 1.6 with a thickness of from 5 to 75 nm is made of zirconia.
9. The lens according to claim 1 , wherein the layer having a refractive index higher than 1.6 with a thickness of from 20 to 75 nm comprises titanium.
10. The lens according to claim 1 , wherein the antireflective coating is deposited on a silica-based sub-layer layer having a thickness of from 100 to 300 nm.
11. The lens according to claim 1 , wherein the mean reflection factor Ruv on said rear face between 280 nm and 380 nm, weighted by the function W(λ) defined in the ISO 13666:1998 standard, is lower than 4.5%, for both an angle of incidence of 30° and an angle of incidence of 45°.
12. The lens according to claim 1 , wherein the mean reflection factor Ruv on said rear face between 280 nm and 380 nm, weighted by the function W(λ) defined in the ISO 13666:1998 standard, is lower than 4.%, for both an angle of incidence of 30° and an angle of incidence of 45°.
13. The lens according to claim 1 , wherein the mean reflection factor on said rear face in the visible region Rm is lower than or equal to 1%.
14. The lens according to claim 1 , wherein the mean light reflection factor on said rear face in the visible region Rv is lower than or equal to 0.90%.
15. The lens according to claim 1 , wherein the mean light reflection factor on said rear face in the visible region Rv is lower than or equal to 0.85%.
16. The lens according to claim 1 , wherein the mean reflection factor Rm_uvi on said rear face between 290 nm and 330 nm is lower than 15%, for an angle of incidence of 15°.
17. The lens according to claim 1 , wherein the mean reflection factor Rm-uv2 on said rear face between 300 nm and 320 nm is lower than 4%, %, for both an angle of incidence of 30° and an angle of incidence of 45°.
18. The lens according to claim 1 , wherein the mean reflection factor Rm-uv2 on said rear face between 300 nm and 320 nm is lower than 3%, for both an angle of incidence of 30° and an angle of incidence of 45°.
19. The lens according to claim 1 , wherein the mean reflection factor Rm-uv3 on said rear face between 300 nm and 380 nm is lower than 5%, for both an angle of incidence of 30° and an angle of incidence of 45°.
20. The lens according to claim 1 , wherein the mean spectral reflection factor over at least 70% of the 280-290 nm range, for an angle of incidence of 15° is higher than 10%.
21. The lens according to claim 1 , wherein the mean reflection factor over at least 20% of the 280-295 nm wavelength range is higher than 5%, for both an angle of incidence of 30° and an angle of incidence of 45°.
22. The lens according to claim 1 , wherein the mean spectral reflection factor for at least one wavelength in the 280-295 nm range for both an angle of incidence of 30° and an angle of incidence of 45° is higher than 5%.