Ophthalmic lens that can be edged, comprising a hydrophobic bilayer and a temporary metal fluoride layer
View Patent ↗An ophthalmic lens that can be edged, includes a main front surface and a main rear surface, obtained by successive deposition on at least one of the main surfaces of the lens, of a first hydrophobic layer that has a thickness of between 6 and 16 nm and is obtained by deposition of a composition including a constituent A selected from fluorosilanes having a number average molar mass that is higher than, or equal to, 2000 g/mol, of a second hydrophobic layer that has a thickness of between 3 and 20 nm and is obtained by the deposition of a composition including a constituent B selected from the fluorosilanes having a number average molar mass than is lower than, or equal to, 900 g/mol, and of a layer including a metal fluoride having a thickness of between 22 and 50 nm.
1. An ophthalmic lens fit for edging, comprising a front main face and a back main face, wherein it is obtained by depositing in succession in this order on at least one of the main faces of the lens and preferably the front main face:
at least one first hydrophobic layer, of a physical thickness of 6 to 16 nm, obtained by depositing a composition comprising a constituent A chosen from fluorinated compounds and preferably perfluorinated compounds containing at least one silanol group or a silanol-group precursor, and the number average molar mass of which is higher than or equal to 2000 g/mol and preferably 2000 to 10000 g/mol;
at least one second hydrophobic layer, of a physical thickness ranging from 3 to 20 nm, obtained by depositing a composition comprising a constituent B chosen from fluorinated compounds and preferably perfluorinated compounds containing at least one silanol group or a precursor thereof and the number average molar mass of which is lower than or equal to 900 g/mol;
at least one temporary layer comprising a metal fluoride, preferably magnesium fluoride, of a physical thickness of 22 to 50 nm; and
optionally a temporary layer comprising a metalloid or metal hydroxide and/or oxide.
2. The ophthalmic lens of claim 1 , wherein the physical thickness of the second hydrophobic layer is from 3 to 10 nm.
3. The ophthalmic lens of claim 2 , wherein the physical thickness of the second hydrophobic layer is from 5 to 8 nm.
4. The ophthalmic lens of claim 1 , wherein the physical thickness of said first hydrophobic layer is from 6 to 15 nm, and the physical thickness of said layer comprising a metal fluoride is from 24 to 40 nm.
5. The ophthalmic lens of claim 1 , wherein the physical thickness of said first hydrophobic layer is from 8 to 12 nm, and the physical thickness of said layer comprising a metal fluoride is from 25 to 38 nm.
6. The ophthalmic lens of claim 1 , wherein the total thickness of the first hydrophobic layer and the second hydrophobic layer is larger than or equal to 13 nm.
7. The ophthalmic lens of claim 1 , wherein the total thickness of the first hydrophobic layer and the second hydrophobic layer is larger than or equal to 15 nm when the thickness of the temporary layer comprising a metal fluoride is larger than or equal to 40 nm.
8. The ophthalmic lens of claim 1 , wherein the metal fluoride is a magnesium fluoride.
9. The ophthalmic lens of claim 1 , wherein it furthermore comprises a layer comprising a metalloid or metal hydroxide and/or oxide deposited on said layer comprising a metal fluoride and in that said metalloid or metal hydroxide and/or oxide is magnesium oxide.
10. The ophthalmic lens of claim 1 , wherein the constituent A possesses a number average molar mass from 3000 to 6000 g/mol and better still from 3000 to 5000 g/mol.
11. The ophthalmic lens of claim 1 , wherein the constituent B possesses a number average molar mass from 300 to 800 g/mol and better still from 400 to 600 g/mol.
12. The ophthalmic lens of claim 1 , wherein only one chain end of the compound A comprises a silanol group or a silanol-group precursor.
13. The ophthalmic lens of claim 1 , wherein only one chain end of the compound B comprises a silanol group or a silanol-group precursor.
14. The ophthalmic lens of claim 1 , wherein the constituent A comprises a compound of formula:
in which
R F represents a straight or branched perfluoroalkyl chain group containing 1 to 16 carbon atoms;
X is a hydrogen, bromine or iodine atom;
Y is a hydrogen atom or a linear or branched alkyl group containing 1 to 6 carbon atoms;
Z is a fluorine atom or a trifluoromethyl group;
R 1 is a hydrolysable group;
R 2 is a hydrogen atom or an inactive monovalent group;
a, b, c and d are integers from 0 to 200;
e is 0 or 1;
m and n are integers from 0 to 2; and
p is an integer from 1 to 10;
Rf, a, b, c, e, m, n and p are chosen so that the average molar mass of the compound of formula (1) is higher than or equal to 2000 g/mol.
15. The ophthalmic lens of claim 14 , wherein the first hydrophobic layer is obtained by depositing a composition comprising from 35 to 60 wt % of a compound of formula (1) and better still 40 to 55 wt % of a compound of formula (1).
16. The ophthalmic lens of claim 1 , wherein the first hydrophobic layer is obtained by depositing a composition comprising at least 40 wt %, better still at least 50 wt %, even better still at least 70 wt % and optimally at least 80 wt % of constituent A.
17. The ophthalmic lens of claim 1 , wherein the two hydrophobic layers are deposited by evaporation.