Optical lens having an interferential coating and a multilayered system for improving abrasion-resistance

1 . An optical lens comprising a substrate having a front main face and a rear main face, said rear main face of which being successively coated with: (A) a first high refractive index sheet having a refractive index higher than 1.55, which does not comprise any Ta2O5 layer; (B) a second low refractive index sheet having a refractive index of 1.55 or less in direct contact with the former sheet (A); (C) a third high refractive index sheet having a refractive index higher than 1.55 in direct contact with the former sheet (B); a monolayer sub-layer having a thickness higher than or equal to 100 nm in direct contact with the former sheet (C); a multilayer interferential coating comprising a stack of at least 6 layers with at least one high refractive index layer having a refractive index higher than 1.55 and at least one low refractive index layer having a refractive index of 1.55 or less, wherein the outermost high refractive index layer having a refractive index higher than 1.55 of the multilayer interferential coating has a thickness lower than 40 nm; wherein a mean reflection factor RUV on said rear main face between 280 nm and 380 nm, weighted by the function W(λ) defined in the ISO 13666:1998 standard, is lower than 10%, for an angle of incidence of 35°; when a high refractive index layer of the interferential coating is an electrically conductive layer and is positioned as the outermost high refractive index layer but is not adjacent to one or more non-conductive high refractive index layers, such electrically conductive layer is not taken into account for the thickness calculation of the outermost high refractive index layer.

2 . The optical lens of claim 1 , wherein the multilayer interferential coating comprises an outermost internal high refractive index layer, the total thickness of the outermost high refractive index layer and the outermost internal high refractive index layer being lower than 100 nm, wherein an outermost internal high refractive index layer of the multilayer interferential coating is the high refractive index layer of the multilayer interferential coating that is furthest from the substrate and positioned just before and not adjacent to the outermost high refractive index layer of the multilayer interferential coating.

3 . The optical lens of claim 1 , wherein the multilayer interferential coating comprises an outermost internal high refractive index layer, the total thickness of the outermost high refractive index layer and the outermost internal high refractive index layer being lower than or equal to 80 nm, wherein an outermost internal high refractive index layer of the multilayer interferential coating is the high refractive index layer of the multilayer interferential coating that is furthest from the substrate and positioned just before and not adjacent to the outermost high refractive index layer of the multilayer interferential coating.

4 . The optical lens of claim 1 , wherein the ratio:

R

T

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1

=

sum

⁢

of

⁢

the

⁢

physical

⁢

thicknesses

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of

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the

⁢

low

⁢

refractive

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index

⁢

layers

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of

⁢

the

⁢

interferential

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coating

sum

⁢

of

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the

⁢

physical

⁢

thicknesses

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of

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the

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high

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refractive

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index

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layers

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of

⁢

the

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interferential

⁢

coating

is higher than or equal to 1.

5 . The optical lens of claim 1 , wherein the ratio:

R

T

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1

=

sum

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of

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the

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physical

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thicknesses

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of

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the

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low

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refractive

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index

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layers

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of

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the

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interferential

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coating

sum

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of

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the

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physical

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thicknesses

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of

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the

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high

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refractive

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index

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layers

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of

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the

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interferential

⁢

coating

is higher than or equal to 1.5.

6 . The optical lens of claim 1 , wherein the sub-layer has a thickness higher than or equal to 120 nm.

7 . The optical lens of claim 1 , wherein the deposition of said sub-layer is performed in a vacuum chamber in which no supplementary gas is supplied during said deposition.

8 . The optical lens of claim 1 , wherein the sub-layer is a SiO 2 -based layer.

9 . The optical lens of claim 1 , wherein said rear main face has a SRT value lower than 1.5.

10 . The optical lens of claim 1 , wherein the first high refractive index sheet (A) having a refractive index higher than 1.55 is a ZrO 2 -based layer or a Ti 3 O 5 based layer; the second low refractive index sheet (B) having a refractive index of 1.55 or less is a SiO 2 -based layer; the third high refractive index sheet (C) having a refractive index higher than 1.55 comprises at least one material selected from Ta 2 O 5 , Nb 2 O 5 , PrTiO 3 , ZrO 2 , Y 2 O 3 , TiO 2 and Ti 3 O 5 .

11 . The optical lens of claim 1 , wherein the interferential coating comprises at least one Ta 2 O 5 -based layer or a ZrO 2 -based layer.

12 . The optical lens of claim 1 , wherein Ruv on the rear face is lower than 5%.

13 . The optical lens of claim 1 , wherein Ruv on the rear face is lower than 2%.

14 . The optical lens of claim 1 , wherein Rv on the rear face is lower than or equal to 1%.

15 . The optical lens of claim 1 , wherein the interferential coating is an anti-reflection coating.

16 . The optical lens of claim 1 , wherein the optical lens is an ophthalmic lens.

17 . The optical lens of claim 1 , wherein the total number of layers in the interferential coating is higher than or equal to 7.

18 . The optical lens of claim 1 , wherein said outermost high refractive index layer having a refractive index higher than 1.55 of the multilayer interferential coating is a non-conductive oxide layer having a thickness lower than or equal to 30 nm.

19 . A method of manufacturing the optical lens of claim 1 , comprising: providing an optical lens comprising a substrate having a front main face and a rear main face; depositing onto at least one main face of the substrate, in this order, a first high refractive index sheet (A) having a refractive index higher than 1.55, which does not comprise any Ta.sub.2O.sub.5 layer, a second low refractive index sheet (B) having a refractive index of 1.55 or less so that it is in direct contact with the former sheet (A), a third high refractive index sheet (C) having a refractive index higher than 1.55 so that it is in direct contact with the former sheet (B), a monolayer sub-layer having a thickness higher than or equal to 100 nm so that it is in direct contact with the former sheet (C); and a multilayer interferential coating comprising a stack of at least 6 layers with at least one high refractive index layer having a refractive index higher than 1.55 and at least one low refractive index layer having a refractive index of 1.55 or less, wherein the outermost high refractive index layer having a refractive index higher than 1.55 of the multilayer interferential coating has a thickness lower than 40 nm; wherein a mean reflection factor R.sub.UV on said rear main face between 280 nm and 380 nm, weighted by the function W(λ) defined in the ISO 13666:1998 standard, is lower than 10%, for an angle of incidence of 35°;

when a high refractive index layer of the interferential coating is an electrically conductive layer and is positioned as the outermost high refractive index layer but is not adjacent to one or more non-conductive high refractive index layers, such electrically conductive layer is not taken into account for the thickness calculation of the outermost high refractive index layer.

20 . The method according of claim 19 , wherein the deposition of the sub-layer is performed in a vacuum chamber in which no supplementary gas is supplied during said deposition.