Article coated with a low refractive index layer based on fluorinated organosilicon compounds
An article including a substrate having at least one main surface coated with a layer A having a refractive index lower than or equal to 1.50, said layer A being obtained by deposition of activated species issued from at least one compound C in gaseous form, containing in its structure at least one Si-fluoroalkyl group, at least one carbon atom, at least one hydrogen atom and optionally at least one nitrogen atom and/or at least one oxygen atom, the deposition of said layer A being carried out by applying a bombardment with an ion beam to layer A while layer A is being formed, and said layer A being formed in the absence of inorganic precursor compounds. Application to the preparation of interferential coatings.
1. An article comprising a substrate having at least one main surface coated with a layer A having a refractive index lower than or equal to 1.50, wherein said layer A was obtained by deposition of activated species issued from at least one compound C in gaseous form, containing in its structure at least one Si—R group, where R is a fluoroalkyl group, at least one carbon atom, at least one hydrogen atom and optionally at least one nitrogen atom and/or at least one oxygen atom, the deposition of said layer A is carried out by applying a bombardment with an ion beam to layer A while layer A is being formed, and said layer A is not formed from inorganic precursor compounds.
2. The article as claimed in claim 1 , wherein the ion beam is emitted by an ion gun.
3. The article as claimed in claim 1 , wherein an atomic percentage of carbon atoms in layer A is lower than 40%.
4. The article as claimed in claim 1 , wherein an atomic percentage of carbon atoms in layer A is lower than 30%.
5. The article as claimed in claim 1 , wherein an atomic percentage of oxygen atoms in layer A is higher than 40%.
6. The article as claimed in claim 1 , wherein an atomic percentage of fluorine atoms in layer A ranges from 0.5 to 8%.
7. The article as claimed in claim 1 , wherein an O/Si atomic ratio in layer A ranges from 2 to 3.5.
8. The article as claimed in claim 1 , wherein layer A has a refractive index lower than or equal to 1.45.
9. The article as claimed in claim 1 , wherein compound C contains at least one group of formula:
where R 1 to R 4 independently designate alkyl, vinyl, aryl, hydroxyl or hydrolyzable groups, and at least one of R 1 to R 4 designates a fluoroalkyl group.
10. The article as claimed in claim 1 , wherein compound C is a compound of formula:
where the X 1 and X 2 groups represent independently an alkyl, a vinyl, an aryl, a hydroxyl or a hydrolyzable group, n designates an integer ranging from 2 to 20 and the R 1a and R 2a groups represent independently a fluoroalkyl group.
11. The article as claimed in claim 1 , wherein the silicon atom or atoms of compound C are not bound to any hydrolyzable or hydroxyl group.
12. The article as claimed in claim 1 , wherein layer A has a thickness ranging from 20 to 150 nm.
13. The article as claimed in claim 1 , wherein layer A has a thickness ranging from 25 to 120 nm.
14. The article as claimed in claim 1 , further defined as an optical lens.
15. The article as claimed in claim 1 , further defined as an ophthalmic lens.
16. The article as claimed in claim 1 , wherein layer A is a layer of a multilayer interferential coating.
17. The article as claimed in claim 16 , wherein the interferential coating is an antireflection coating.
18. A process for manufacturing a coated article of claim 1 , comprising:
providing an article comprising a substrate having at least one main surface;
depositing on said main surface of the substrate a layer A having a refractive index lower than or equal to 1.50;
recovering the coated article comprising the substrate having the main surface coated with said layer A, wherein said layer A is obtained by deposition of activated species issued from at least one compound C in gaseous form, containing in its structure at least one Si—R group, where R is a fluoroalkyl group, at least one carbon atom, at least one hydrogen atom and, optionally, at least one nitrogen atom and/or at least one oxygen atom; and
deposition of said layer A is carried out by applying a bombardment with an ion beam to layer A while layer A is being formed, and said layer A is not formed from inorganic precursor compounds.
19. The article as claimed in claim 1 , wherein an atomic percentage of carbon atoms in layer A ranges from 3 to 40%.
20. The article as claimed in claim 1 , wherein an O/Si atomic ratio in layer A ranges from 0.1 to 3.