Method for designing a mould for casting a semi-finished ophthalmic lens blank and computer program product for carrying out said method
View Patent ↗A method for designing a mould ( 120 ) for casting a semi-finished ophthalmic lens blank, wherein the surface of the mould ( 120 ) is designed so that the surface of the mould fits a predetermined closed curve, wherein the predetermined closed curve is representative of the geometry of a gasket ( 160 ) to be used in association with the mould ( 10 ). A method for assembling a mould assembly ( 100 ) and a method for casting a semi-finished ophthalmic lens blank, and a computer program product including software code portions for performing steps of these methods are also described.
1. A method for designing a mould for casting a semi-finished ophthalmic lens blank, the method comprising the steps of:
determining a closed curve representative of a geometry of a gasket to be used in combination with the mould with the closed curve being at a periphery of mould, wherein the determined closed curve corresponds to a desired shape of an edge of the mould;
using an optimization process with desired optical properties of the semi-finished ophthalmic lens blank to be cast in the mould and the determined closed curve as inputs of the optimization process, designing a surface of the mould so that said surface of the mould is regressive and substantially fits the determined closed curve with a distance between each point of the determined closed curve and said surface of the mould being less than 0.1 mm, wherein a distance between an outer edge ( 304 ) of an optically usable cavity area ( 306 ) of the mould and an edge of an outermost perimeter ( 302 ) of the mould is constant; and
manufacturing the mould with the designed surface.
2. The method according to claim 1 , wherein the surface of the mould is complex and data representative of said complex surface are used as input of the optimization process.
3. The method according to claim 1 , wherein said closed curve is comprised in one plane.
4. The method according to claim 1 , comprising a step of designing a facet of the mould which extends outwardly from said surface.
5. The method according to claim 4 , wherein said closed curve is comprised in one plane, and the facet is comprised in said plane.
6. The method according to claim 1 , wherein the height of all points of said closed curve relative to the bottom of the mould is equal.
7. A method for assembling a mould assembly comprising the steps of:
providing a mould for casting a semi-finished ophthalmic lens blank designed according to claim 1 ,
providing a gasket having the closed curve used for designing the mould,
assembling the mould and the gasket.
8. A method for casting a semi-finished lens blank comprising the steps of:
assembling a mould assembly according to the method of claim 7 ;
casting said semi-finish lens blank in a casting cavity formed in the mould assembly.
9. A non-transitory computer program medium comprising one or more stored sequence of instruction that is accessible to a processor and which, when executed by the processor, causes the processor to carry out the steps of claim 1 .
10. The method according to claim 2 , wherein said closed curve is comprised in one plane.
11. The method according to claim 2 , comprising a step of designing a facet of the mould which extends outwardly from said surface.
12. The method according to claim 3 , comprising a step of designing a facet of the mould which extends outwardly from said surface.
13. The method according to claim 1 , wherein the height of all points of said closed curve relative to the bottom of the mould is equal.
14. The method according to claim 2 , wherein the height of all points of said closed curve relative to the bottom of the mould is equal.
15. The method according to claim 5 , wherein the height of all points of said closed curve relative to the bottom of the mould is equal.
16. A method for assembling a mould assembly comprising the steps of:
providing a mould for casting a semi-finished ophthalmic lens blank designed according to claim 1 ,
providing a gasket, having the closed curve used for designing the mould,
assembling the mould and the gasket.
17. A method for assembling a mould assembly comprising the steps of:
providing a mould for casting a semi-finished ophthalmic lens blank designed according to claim 2 ,
providing a gasket, having the closed curve used for designing the mould,
assembling the mould and the gasket.
18. A method for assembling a mould assembly comprising the steps of:
providing a mould for casting a semi-finished ophthalmic lens blank designed according to claim 5 ,
providing a gasket, having the closed curve used for designing the mould,
assembling the mould and the gasket.