Antireflection ophthalmic lens and method of manufacture method

1. An optical article, comprising:

a transparent substrate of organic glass;

an adhesive layer covering at least one of the faces of the transparent substrate;

a transparent film of thermoplastic polymer fixed on the transparent substrate by means of an adhesive layer;

an anti-abrasion hard coating covering the transparent film of thermoplastic polymer; and

a multilayer antireflection coating formed from alternating mineral layers with high and low refractive index;

wherein the thermoplastic polymer forming the transparent film is selected from cellulose triacetate (CTA) and poly(ethylene terephthalate) (PET); and

the adhesive layer is a layer of pressure-sensitive adhesive or a layer of hot-melt adhesive.

2. The optical article according to claim 1 , wherein the thermoplastic polymer forming the transparent film has a glass transition temperature, measured by dynamic mechanical analysis, between 50° C. and 250° C.

3. The optical article according to claim 2 , wherein the thermoplastic polymer forming the transparent film has a glass transition temperature, measured by dynamic mechanical analysis, between 70° C. and 200° C.

4. The optical article according to claim 1 , wherein the transparent film of thermoplastic polymer has a thickness between 50 μm and 150 μm.

5. The optical article according to claim 1 , wherein the anti-abrasion coating has a thickness between 1 μm and 15 μm.

6. The optical article according to claim 1 , wherein the thickness of the adhesive layer is between 10 μm and 40 μm.

7. A method of manufacturing an optical article according to claim 1 , comprising the steps of:

providing a transparent substrate of organic glass;

depositing an anti-abrasion coating on a transparent film of thermoplastic polymer thus forming a bilayer structure;

gluing the bilayer structure by means of an adhesive layer onto the transparent substrate; and

forming a multilayer antireflection coating consisting of alternating mineral layers of high and low refractive index, on the anti-abrasion hard coating.

8. The method according to claim 7 , wherein the gluing step is preceded by a step of thermoforming of the bilayer structure at a temperature below the glass transition temperature of the thermoplastic polymer.

9. The optical article according to claim 7 , wherein said transparent substrate is a substrate of an ophthalmic lens.

10. The optical article according to claim 1 , wherein the thermoplastic polymer forming the transparent film has a glass transition temperature, measured by dynamic mechanical analysis, between 70 and 200° C.

11. The optical article according to claim 1 , wherein the transparent film of thermoplastic polymer has a thickness between 60 μm and 100 μm.

12. The optical article according to claim 1 , wherein the anti-abrasion coating has a thickness between 2 μm and 10 μm.

13. The optical article according to claim 1 , wherein the thickness of the adhesive layer is between 15 and 30 μm.

14. The optical article according to claim 1 , wherein said transparent substrate of organic glass is a substrate of an ophthalmic lens.

15. A method for reducing the cracking of the antireflection coating of an optical article comprising a transparent substrate of organic glass, an anti-abrasion coating and a multilayer antireflection coating formed from alternating mineral layers with high and low refractive index; said method comprising the step of:

positioning a transparent film of thermoplastic polymer selected from cellulose triacetate (CTA) and poly(ethylene terephthalate) (PET) between the transparent substrate and the anti-abrasion coating, said transparent film being fixed on the transparent substrate by means of an adhesive layer selected from a layer of pressure-sensitive adhesive or a layer of hot-melt adhesive.