Cold antireflection layer deposition process
View Patent ↗The invention concerns a method for making an antiglare stack by vacuum evaporation on an organic substrate ( 1 ) at a temperature lower than 150° C., comprising steps which consist in depositing at least a layer of material having a refractive index different from that of MgF 2 ( 4, 4 ′), preparing the surface of the thus coated substrate, and depositing an outer MgF 2 layer ( 5 ) without ionic assistance. The resulting antiglare stack on organic substrate exhibits good adherence and good scratch resistance. The invention is applicable to ophthalmic lenses.
1. A process for manufacturing a multilayer antireflection coating, the process comprising the following steps:
deposition of a first layer of material of refractive index different from MgF 2 ;
deposition of a layer of material having a low refractive index;
deposition of a second layer of material of refractive index different from MgF 2 , and having a thickness of 120 to 130 nm;
preparation of a surface of an organic substrate thus coated with a surface preparation selected from a group consisting of ion bombardment, electron bombardment and etching carried out ex situ; and
deposition of an outer layer of MgF 2 without ion assistance;
wherein the depositions take place by vacuum evaporation on the substrate at a temperature below 150° C.
2. The process as claimed in claim 1 , in which the vacuum evaporation is carried out at a temperature below 100° C.
3. The process as claimed in claim 2 , in which said layer of material of refractive index different from MgF 2 is made of a material having a high refractive index chosen from a group of simple or mixed oxides or mixtures of metals of groups IIIb , IVb, Vb, VIb, VIIb and lanthanides.
4. The process as claimed in claim 3 , in which the metals are chosen from the group consisting of Pr, La, Ti, Zr, Ta and Hf.
5. The process as claimed in claim 3 , in which the materials having a high refractive index are chosen from the group consisting of ZrO 2 , PrTiO 3 , Pr 2 O 3 /TiO 2 mixtures, Pr 6 O 11 /TiO 2 mixtures, La 2 O 3 /TiO 2 mixtures and ZrO 2 /TiO 2 mixtures.
6. The process as claimed in claim 1 , wherein said layer of material of refractive index different from MgF 2 is a hard coating.
7. The process as claimed in claim 1 , wherein said layer of material of refractive index different from MgF 2 is an impact-resistant layer.
8. The process as claimed in claim 1 , wherein said layer of material of refractive index different from MgF 2 is an antifringe layer.
9. The process as claimed in claim 7 , wherein said layer of material of refractive index different from MgF 2 is an antifringe layer.
10. The process as claimed in claim 1 , in which the layer of low refractive index has a physical thickness of between 40 and 200 nm.
11. The process as claimed in claim 1 , in which the layer having a low refractive index is made of SiO 2 .
12. The process as claimed in claim 1 , in which the first layer of material of refractive index different from MgF 2 has a physical thickness of 10 to 40 nm.
13. The process as claimed in claim 11 , in which the first layer of material of refractive index different from MgF 2 has a physical thickness of 10 to 40 nm.
14. The process as claimed in claim 1 , in which the layer of material having a low refractive index has a thickness of 10 to 100 nm.
15. The process as claimed in claim 1 , in which the organic substrate comprises polycarbonate.
16. The process as claimed in claim 1 , in which the outer layer of MgF 2 has a physical thickness of 50 to 100 nm.
17. The process as claimed in claim 1 , comprising the subsequent step of depositing a layer that modifies surface energy.
18. A process for manufacturing a multilayer antireflection coating, the process comprising the following steps:
deposition of a first layer of material of refractive index different from MgF 2 ;
deposition of a layer of material having a low refractive index;
deposition of a second layer of material of refractive index different from MgF 2 , and having a thickness of 120 to 130 nm;
preparation of a surface of an organic substrate thus coated with a surface preparation selected from a group consisting of ion bombardment, electron bombardment and etching carried out ex situ; and
deposition of an outer layer of MgF 2 without ion assistance to improve the adhesion of a multilayer antireflection coating that includes MgF 2 on the substrate;
wherein the depositions take place by vacuum evaporation on the substrate at a temperature below 150° C.