The invention relates to a mold insert, the interior surface thereof having an average quadratic roughness of less than 10 nm. Said insert is covered with a protective layer exhibiting a Vickers hardness of more than 1000 HV, a thickness of between 0.2 and 5 μm, and an adhesive strength greater than 15 N. The invention also relates to a method for the production thereof. The invention is used for the production of ophthalmic lenses.
1. A device for molding an ophthalmic lens, the device comprising a molding insert which bears markings configured for transfer to the ophthalmic lens, wherein an internal surface of the insert has a mean square roughness R ms of less than 10 nm, and wherein the internal surface of the insert is coated with a protective coating having a Vickers hardness of greater than 1000 HV, a thickness of between 2 and 5 μm and a critical adhesion which is greater than 15 N.
2. The device as claimed in claim 1 , in which the protective coating is made of DLC.
3. The device as claimed in claim 1 , in which the insert bearing the protective coating is made of steel or glass.
4. The device as claimed in claim 1 , in which the insert coated with the protective coating has an average surface roughness of less than 7 nm.
5. The device as claimed in claim 1 , in which the protective coating has a Vickers hardness of greater than 1500 HV.
6. A process for manufacturing an ophthalmic lens molding insert, comprising:
machining and polishing an internal surface of the insert until a mean square roughness R ms of less than 10 nm is obtained; and
depositing a protective coating on the internal surface such that markings on the insert for transfer to the ophthalmic lens remain visible after the protective coating is deposited, the protective coating having a Vickers hardness of greater than 1000 HV, a thickness of between 2 and 5 μm and a critical adhesion of greater than 15 N.
7. The process as claimed in claim 6 , in which the protective coating is deposited by CVD.
8. The device as claimed in claim 1 , wherein the device is configured to manufacture ophthalmic lenses by injection molding.
9. The device as claimed in claim 8 , in which the ophthalmic lens is a progressive lens.
10. The device as claimed in claim 9 , in which the ophthalmic lens is made of polycarbonate.
11. The device as claimed in claim 2 , in which the insert bearing the protective coating is made of steel or glass.
12. The device as claimed in claim 1 , wherein the markings remain visible after the protective coating is applied to the internal surface of the insert.
13. The device as claimed in claim 1 , wherein the internal surface of the insert is a progressive surface.
14. The process as claimed in claim 6 , wherein the internal surface of the insert is a progressive surface.