Method for manufacturing an ophthalmic article through taping
The method of using adhesive tapes to form mold cavities around a wafer with microstructures addresses the challenges of high cost and complexity in thermoset lens manufacturing, providing accessible and effective ophthalmic lenses with microstructures.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- ESSILOR INTERNATIONAL(COMPAGNIE GENERALE D OPTIQUE)
- Filing Date
- 2025-12-16
- Publication Date
- 2026-06-25
AI Technical Summary
The manufacturing of thermoset ophthalmic lenses with surface microlenses is challenging due to the high cost and complexity of molds, especially those with microstructures, and the lengthy curing process, making them inaccessible to many, including the indigent population.
A method involving the use of adhesive tapes to form mold cavities around a wafer with microstructures, allowing for the encapsulation of the wafer between two lens substrates using polymerizable materials, which are then polymerized to create ophthalmic articles.
This method reduces manufacturing time and cost, enabling the production of ophthalmic lenses with microstructures like microlenses or Fresnel rings, making them more accessible and effective in controlling myopia progression.
Smart Images
Figure EP2025087374_25062026_PF_FP_ABST
Abstract
Description
DescriptionTitle: Method for manufacturing an ophthalmic article through tapingTechnical Field
[0001] This disclosure pertains to the field of ophthalmic lens manufacturing, and in particularto such manufacturing methods for casting thermoset ophthalmic lenses. More in particular, the present disclosure pertains to the field of manufacturing method for casting thermoset ophthalmic lenses having a wafer embedded therein.Background Art
[0002] Myopia is a prevalent disorder: in 2000 about 23% of the world population (i.e. 1 .4 billion people) were nearsighted and according to the Brien Holden Vision Institute in Australia, 50% of the global population will be myopic by 2050. It is known that high myopia increases the risk of sightthreatening problems such as retinal detachment, cataracts and glaucoma. Hence, slowing myopia progression in children is crucial. Studies conducted in recent years show that using microlenses on the front face (convex surface) of a regular single vision lens to introduce myopic defocus in the periphery effectively slows myopia progression. Unfortunately, casting thermoset lenses with surface microlenses remains challenging.
[0003] The thermoset lens casting method makes use of a mold assembly comprising two mold parts sealed together with a gasket or adhesive tape to form a cavity between the two mold parts and the cavity is filled with a polymerizable material. The mold assembly is then placed in an oven and the polymerizable material is cured for several hours. Eventually, the resulting lenses are collected after demolding.
[0004] Unlike the continuous injection molding method, the thermoset lens casting method is lengthy due to the time required to cure the polymerizable material fully. It is thus carried out in batches requiring a high number of molds to meet the volume demand and to reach the cost targets. Typically, the material used for the molds is glass and / or nickel. To save cost, the molds must be cleaned between batches so that they can be reused. Although cheaper than using new molds each time, reusing the molds requires an extensive cleaning process.
[0005] In the case of thermoset lenses with surface microstructures such as microlenses or Fresnel rings, molds with negative microstructures on either one of the faces of the lenses are required. Unfortunately, manufacturing such molds using glass is not yet technically feasible even with micromachining due to the precision needed for the microstructures. As for molds made of nickel, their manufacturing is excessively pricey either through micromachining or replication of a master mold, in particular when considering the large number of molds required for a batch of casting.
[0006] Therefore, a cost effective solution for providing ophthalmic lenses with myopic defocus is still needed to make them widely accessible, even to the indigents, and eventually overcome the myopia epidemic.Summary
[0007] This disclosure improves the situation.
[0008] The present invention provides a method for manufacturing an ophthalmic article, comprising:- positioning a wafer at a first predetermined distance from a first mold part; wherein the wafer comprises a first wafer face, a second wafer face opposite the first wafer face and a wafer edge joining the first and second wafer faces; wherein the first mold part comprises a first molding surface and a first mold edge extending from the first molding surface; wherein positioning results in the first wafer face facing the first molding surface;- adhering a first adhesive tape to both the wafer edge and the first mold edge through a first adhesive surface thereof; wherein the first adhesive surface extends between the wafer edge and the first mold edge; thereby forming a first mold cavity defined by the first wafer face, the first molding face and the first adhesive surface and obtaining a partial mold assembly with an assembly edge;- positioning a second mold part having a second molding surface and a second mold edge extending from the second molding surface at a second predetermined distance to the partial mold assembly so that the second wafer face faces the second molding surface;- adhering a second adhesive tape to both the assembly edge and the second mold edge through a second adhesive surface thereof; wherein the second adhesive surface extends between the assembly edge and the second mold edge; thereby forming a second mold cavity defined by the second wafer face, the second molding face and the second adhesive surface and obtaining a full mold assembly;- filling the first mold cavity with a first polymerizable material;- filling the second mold cavity with a second polymerizable material; and- polymerizing the first and second polymerizable materials.
[0009] Although this method was developed as a solution to encapsulate an ophthalmic wafer having microstructures between two lens substrates, it can be advantageously used also for any ophthalmic article having an ophthalmic wafer of any kind between two lens substrates.
[0010] Other optional and non-limiting features are as follows.
[0011] Positioning the wafer at the first predetermined distance from the first mold part may comprise centering the wafer relatively to the first mold part and bringing the wafer to the first predetermined distance from the first mold part.
[0012] In such case, positioning the wafer at the first predetermined distance from the first mold part may optionally be carried out through a positioning tool comprising two parts: one top part adapted to engage with a convex surface and one bottom part adapted to engage with a concave surface; wherein each of the convex surface and the concave surface being one of the first face and the first molding surface.
[0013] In this latter case, positioning the wafer at the first predetermined distance from the first mold part may optionally comprise determining a first reference distance between the top part and theconvex surface and determining a second reference distance between the bottom part and the concave surface.
[0014] In this latter case, bringing the wafer to the first predetermined distance from the first mold part may optionally take into account the first reference distance and the second reference distance.
[0015] The top tool part may comprise a centering ring.
[0016] The bottom part may comprise a support plate, and optionally an edge ring.
[0017] In all these cases, positioning the second mold part at the second predetermined distance from the partial mold assembly may optionally comprise centering the second mold part relatively to the partial mold assembly and bringing the second mold part to the second predetermined distance from the partial mold assembly.
[0018] In this latter case, positioning the wafer at the first predetermined distance from the first mold part may optionally be carried out through a positioning tool comprising two parts: one top part adapted to engage with a convex surface and one bottom part adapted to engage with a concave surface; wherein each of the convex surface and the concave surface being one of the second face and the second molding surface.
[0019] In this latter case, positioning the second mold part at the second predetermined distance from the partial mold assembly may optionally comprises determining a third reference distance between the top part and the convex surface and determining a fourth reference distance between the bottom part and the concave surface.
[0020] In this latter case, bringing the second mold part to the second predetermined distance from the partial mold assembly may optionally consider the third reference distance and the fourth reference distance.
[0021] The top tool part may comprise a centering ring.
[0022] The bottom part may comprise a support plate, and optionally an edge ring.
[0023] In all these cases, the first molding surface may have a convex surface, and the second molding surface a concave surface. In such case, the first wafer face is a concave surface, and the second wafer face is a convex surface.
[0024] Alternatively, the first molding surface may be a concave surface, and the second molding surface may be a convex surface. In such case, the first wafer face may be a convex surface, and the second wafer face may be a concave surface.
[0025] In all these cases, filling the first mold cavity and filling the second mold cavity may optionally be carried out simultaneously.
[0026] In all these cases, the first adhesive tape may optionally be applied around the wafer edge and the first mold edge from a first tape head to a first tape tail covering the first tape head; the second adhesive tape around the assembly edge and the second mold edge from a second tapehead to a second tape tail covering the second tape head; wherein the second tape head does not cover the first tape tail.
[0027] In this latter case, the method may optionally comprise prior to filling the first mold cavity, removing the first tape tail and prior to filling the second mold cavity, removing the second tape tail.
[0028] In this latter case, removing the first tape tail and removing the second tape tail may be caried out simultaneously. Alternatively, removing the second tape tail may be carried out prior to removing the first tape tail.
[0029] In all these cases, the first polymerizable material and the second polymerizable material may be polymerized simultaneously.
[0030] In all these cases, the first polymerizable material and the second polymerizable material may be the same. Alternatively, the first polymerizable material and the second polymerizable material are different.
[0031] In all these cases, the wafer may comprise microstructures. In such case, the microstructures may optionally be myopia controlling microstructures or polarizing microstructures. The microstructures may be at least one of microlenses and Fresnel rings.Brief Description of Drawings
[0032] Other features, details and advantages will be shown in the following detailed description and on the figures, on which:Fig. 1 is cross-section of a schematic illustration of a mold assembly according to the invention;Fig. 2 is cross-section of a schematic illustration of an exemplified embodiment of the mold assembly according to the invention;Fig. 3 is cross-section of a schematic illustration of another exemplified embodiment of the mold assembly according to the invention;Fig. 4 is a diagram illustrating the method for manufacturing an ophthalmic article according to the present invention;Fig. 5 is a diagram illustrating the positioning of the wafer at a first predetermined distance from the first mold part;Fig. 6 is a diagram illustrating the positioning of the second mold part at a second predetermined distance from the partial mold assembly;Fig. 7 illustrates an exemplified embodiment of the method for manufacturing an ophthalmic article according to the present invention through the mold assembly of Fig. 2; andFig. 8 illustrates another exemplified embodiment of the method for manufacturing an ophthalmic article according to the present invention through the mold assembly of Fig. 3.Description of Embodiments
[0033] A mold assembly according to the invention will be described in further details hereafter with reference to Fig. 1 to Fig. 3.
[0034] Such mold assembly 10 comprises a first mold part 11 , a second mold part 12, a wafer 13, a first adhesive tape 14 and a second adhesive tape 16. The first mold part 11 , the wafer 13 and the first adhesive tape 14 form together a first mold cavity 15 and will be referred together as a partial mold assembly 100 having an assembly edge 101. The second mold part 12, the wafer 13 and the second tape 16 form together a second mold cavity 17.
[0035] The first mold part 11 comprises a first molding surface 111 and a first mold edge 113 extending from the first molding surface 111. It may also comprise a non-molding surface 112 opposite the first molding surface 111. In such case, the first mold edge 113 connects the first molding surface 111 and the non-molding surface 112 of the first mold part 11 .
[0036] The first mold part 11 preferably has a general shape with rotational symmetry so that the axis of rotation passes through the first molding surface 111 and the non-molding surface 112 of the first mold part 11.
[0037] The material of the first mold part 11 may be chosen from glass, metal and plastic.
[0038] The second mold part 12 comprises a second molding surface 121 and a second mold edge 123 extending from the second molding surface 121. It may also comprise a non-molding surface 122 opposite the second molding surface 121. In such case, the second mold edge 123 connects the second molding surface 121 and the non-molding surface 122 of the second mold part 12.
[0039] The second mold part 12 preferably has a general shape with rotational symmetry so that the axis of rotation passes through the second molding surface 121 and the non-molding surface 122 of the second mold part 11.
[0040] The material of the second mold part 12 may be chosen from glass, metal and plastic.
[0041] The term “wafer” refers to a layer of material of optical quality that is intended to be included into an ophthalmic article such as an ophthalmic lens, notably between two lens substrates. This layer of material typically provides the ophthalmic article with a function, mostly optical function, in addition to the functions of the lens substrates. An example of such functions is myopia controlling. Another example of such functions is polarization. However, the invention is not limited to these exemplified functions; the function may be any useful function obtainable through an ophthalmic wafer.
[0042] The functions can be provided in several ways. One way is to provide the wafer with microstructures, such as microlenses and Fresnel rings. More than one type of microstructures can be used at the same time on one wafer. For example, both microlenses and Fresnel rings may be provided on the same wafer.
[0043] The wafer 13 comprises a first wafer face 131 , a second wafer face 132 opposite the first wafer face 131 , and a wafer edge 133 joining the first wafer face 131 and the second wafer face 132. The first wafer face 131 faces the first molding surface 111 while the second wafer face 132 faces the second molding surface 121.
[0044] The wafer 13 may be a single layer. In such case, when microstructures are provided, they may be provided on either side of the single layer or both.
[0045] The wafer 13 may be a multilayer. In such case, when microstructures are provided, they may be provided in any of the layers, including the outmost layers or the interface between two layers.
[0046] The wafer 13 preferably has a general shape with rotational symmetry so that the axis of rotation passes through the first wafer face 131 and the second wafer face 132.
[0047] The material of the wafer 13 may be chosen from one or several thermoplastic materials such as polycarbonate (PC), alicyclic polycarbonate copolymer, poly(methyl methacrylate) (PMMA), poly(methyl methacrylimide) (PMMI), polyamide (PA), polyester, copolyester, polysulfone (PSU), cellulose triacetate (TAC), thermoplastic polyurethane (TPU), and cyclic olefin copolymer (COC). The ophthalmic wafer may also be made of one or several thermoset materials such as polyurethane, allyl diglycol carbonate, polythiourethane, episulfur polymers, epoxy, poly(meth)acrylates, polythiomethacrylates. This list of compounds does not limit the choice of thermoplastic or thermoset materials which could be used for the process for making the wafer. When the ophthalmic wafer is made of a plurality of layers, in one embodiment, all the layers may be made of thermoplastic materials. In another embodiment, all the layers may be made of thermoset materials. In still another embodiment, the wafer may be made of a combination of layers made of thermoplastic materials and layers made of thermoset materials.
[0048] The distance between the first molding surface 111 and the first wafer face 131 is shown in the figures as L1. The distance between the second molding surface 111 and the second wafer face 131 is shown in the figures as L2. These distances are taken at the center of the mold assembly 10, preferably along the axis of rotational symmetry.
[0049] The first adhesive tape 14 comprises a first adhesive surface 141 which adheres to the wafer edge 133 and the first mold edge 113, so that the first adhesive surface 141 extends between the wafer edge 133 and the first mold edge 113 in its width direction. The first adhesive tape 14 extends in the perpendicular direction (longitudinal direction) around the wafer edge 133 and the first mold edge 113 from a first tape head to a first tape tail. Preferably, the first tape tail covers the first tape head.
[0050] The second adhesive tape 16 comprises a second adhesive surface 161 adhering to the second mold edge 123 and the assembly edge 101 , so that the second adhesive surface 161 extends between the second mold edge 123 and the assembly edge 101 in its width direction. The second adhesive tape 16 extends in the perpendicular direction (longitudinal direction) around the assembly edge 101 and the second mold edge 123 from a second tape head to a second tape tail. Preferably, the second tape tail covers the second tape head.
[0051] The second tape head may or may not cover the first tape tail but preferably does not.
[0052] Fig. 2 shows one particular embodiment for the mold assembly. Similar elements between Fig. 1 and Fig. 2 are given similar reference signs, with the only different being the first digit, which is “1 ” is Fig. 1 and “2” in Fig. 2. The difference between the mold assembly of Fig. 1 and that of Fig. 2is that in Fig. 1 the shapes of the different surfaces and faces are not specified (dashed lines), by contrast with those of Fig. 2.
[0053] In this embodiment, the first molding surface 211 of the first mold part 21 is convex and the non-molding surface 212 thereof is concave. The second molding surface 221 of the second mold part 22 is concave while its non-molding surface 222 is convex. The first wafer face 231 is concave while the second wafer face 232 is convex.
[0054] Fig. 3 shows one particular embodiment for the mold assembly. Similar elements between Fig. 1 and Fig. 3 are given similar reference signs, with the only difference being the first digit, which is “1 ” is Fig. 1 and “3” in Fig. 3. The difference between the mold assembly of Fig. 1 and that of Fig. 3 is that in Fig. 1 the shapes of the different surfaces and faces are not specified (dashed lines), by contrast with those of Fig. 3.
[0055] In this embodiment, the first molding surface 311 of the first mold part 31 is concave and the non-molding surface 312 thereof is convex. The second molding surface 321 of the second mold part 32 is convex while its non-molding surface 322 is concave. The first wafer face 331 is convex while the second wafer face 332 is concave.
[0056] The invention is not limited to these exemplified embodiments. Any of the surfaces and faces may be concave or convex independently from each other.
[0057] A method for manufacturing an ophthalmic article according to the invention will be described hereafter with reference to Fig. 4 to 6. In the following, description is provided with reference to the mold assembly 10 of Fig. 1. However, it can be easily read with reference to the embodiments of Fig. 2 and Fig. 3 by changing the first digit of the reference signs to the corresponding one, i.e. “2” for Fig. 2 and “3” for Fig. 3.
[0058] The method comprises:- positioning S100 a wafer 13 at a first predetermined distance L1 from a first mold part 11 ; wherein the wafer 13 comprises a first wafer face 131 , a second wafer face 132 opposite the first wafer face and a wafer edge 133 joining the first and second wafer faces 131 , 132; wherein the first mold part 11 comprises a first molding surface 111 and a first mold edge 113 extending from the first molding surface 111 ; wherein positioning results in the first wafer face 131 facing the first molding surface 111 ;- adhering S200 a first adhesive tape 14 to both the wafer edge 133 and the first mold edge 113 through a first adhesive surface 141 thereof; wherein the first adhesive surface 141 extends between the wafer edge 133 and the first mold edge 113; thereby forming a first mold cavity 15 defined by the first wafer face 131 , the first molding face 111 and the first adhesive surface 141 and obtaining a partial mold assembly 100 with an assembly edge 101 ;- positioning S300 a second mold part 12 having a second molding surface 121 and a second mold edge 123 extending from the second molding surface 121 at a second predetermined distance L2 to the partial mold assembly 100 so that the second wafer face 132 faces the second molding surface 121 ;- adhering S400 a second adhesive tape 16 to both the assembly edge 101 and the second mold edge 123 through a second adhesive surface 161 thereof; wherein the second adhesive surface 161 extends between the assembly edge 101 and the second mold edge 123; thereby forming a second mold cavity 17 defined by the second wafer face 132, the second molding face 121 and the second adhesive surface 161 and obtaining a full mold assembly 10;- filling S600 the first mold cavity 15 with a first polymerizable material;- filling S650 the second mold cavity 17 with a second polymerizable material;- polymerizing S700 the first and second polymerizable materials.
[0059] Positioning S100 the wafer 13 at the first predetermined distance L1 from the first mold partI I may comprise centering S110 the wafer 13 relatively to the first mold part 11 and bringing S130 the wafer 13 to the first predetermined distance L1 from the first mold part 11. One option is to use a positioning tool 40. This positioning tool 40 may comprise two parts: one top part 41 and one bottom part 42. Here, the relative terms “top” and “bottom” refer to the position of the parts during operation.
[0060] The top part 41 may be adapted to engage with a convex surface. For example, the top part 41 of the positioning tool 40 may comprise a centering ring. During positioning S100 the wafer 13 at the first predetermined distance L1 from the first mold part 11 , the convex surface may be one of the second face 132 of the wafer 13 and a non-molding surface 112 of the first mold part 11 opposite the first molding surface 111. For example, in the embodiment of Fig. 2, the convex surface is the second face 232 of the wafer 23; in the embodiment of Fig. 3, the convex surface is the non-molding surface 312 of the first mold part 31.
[0061] The bottom part 42 may be adapted to engage with a concave surface. For example, the bottom part comprises a support plate 421 , and optionally an edge ring 422. The concave surface may be one of the second face 132 of the wafer 13 and the non-molding surface 112 of the first mold part 11. For example, in the embodiment of Fig. 2, the concave surface is the non-molding surface 212 of the first mold part 21 ; in the embodiment of Fig. 3, the concave surface is the second face 232 of the wafer 23.
[0062] Positioning S100 the wafer 13 at the first predetermined distance L1 from the first mold partI I I may further comprise determining S120 a first reference distance and a second reference distance. The first reference distance may be for example between the top part 41 of the positioning tool 40 and one among the wafer 13 and the first mold part 11 ; for example, the one with the convex surface. The second reference distance may be between the bottom part 42 and the other one among the wafer 13 and the first mold part 11 ; for example, the one with the concave surface.
[0063] In such case, bringing S130 the wafer 13 to the first predetermined distance L1 from the first mold part 111 takes into account the first reference distance and the second reference distance.
[0064] Adhering S200 the first adhesive tape 14 to both the wafer edge 133 and the first mold edge 113 may comprise applying the first adhesive tape 14 around the wafer edge 133 and the first mold edge 113 from a first tape head to a first tape tail covering the first tape head.
[0065] Positioning S300 the second mold part 12 at the second predetermined distance L2 from the partial mold assembly 100 may comprise centering S310 the second mold part 12 relatively to the partial mold assembly 100 and bringing S330 the second mold part 12 to the second predetermined distance from the partial mold assembly. Again, one option is to use a positioning tool 40 such as the one described above.
[0066] When the top part 41 is adapted to engage with a convex surface, during positioning S300 the second mold part 12 at the second predetermined distance L2 from the partial mold assembly 100, the convex surface may be one of a non-molding surface 122 of the second mold part 12 opposite the second molding surface 121 and the non-molding surface 112 of the first mold part 11. For example, in Fig. 2, the convex surface is the non-molding surface 222 of the second mold part 22; in Fig. 3, the convex surface is the non-molding surface 312 of the first mold part 31.
[0067] When the bottom part 42 is adapted to engage with a concave surface during positioning S300 the second mold part 12 at the second predetermined distance L2 from the partial mold assembly 100, the concave surface may be one of a non-molding surface 122 of the second mold part 12 opposite the second molding surface 121 and the non-molding surface 112 of the first mold part 11. For example, in Fig. 2, the concave surface is the non-molding surface 212 of the first mold part 21 ; in Fig. 3, the concave surface is the non-molding surface 322 of the second mold part 32.
[0068] Positioning S300 the second mold part 12 at the second predetermined distance L2 from the partial mold assembly 100 may comprise determining S320 a third reference distance and a fourth reference distance. The third reference distance may be for example between the top part 41 of the positioning tool 40 and one among the partial mold assembly 100 and the second mold part 12; for example, the one with the convex surface. The fourth reference distance may be for example between the bottom part 42 of the positioning tool 40 and one among the partial mold assembly 100 and the second mold part 12; for example, the one with the concave surface.
[0069] In such case, bringing S330 the second mold part to the second predetermined distance L2 from the partial mold assembly 100 considers the third reference distance and the fourth reference distance.
[0070] Adhering S400 the second adhesive tape 16 to both the assembly edge 101 and the second mold edge 123 may comprise applying the second adhesive tape 16 around the assembly edge 101 and the second mold edge 123 from a second tape head to a second tape tail covering the second tape head. Preferably, the second tape head does not cover the first tape tail.
[0071] The method may comprise before filling S600 the first mold cavity 15, removing S500 the first tape tail. The method may comprise before filing S650 the second mold cavity 17, removing S550 the second tape tail. Removing S500 the first tape tail and removing S550 the second tape tail may be carried out simultaneously. Alternatively, removing S550 the second tape tail is carried out prior to removing S500 the first tape tail.
[0072] Preferably, filling S600 the first mold cavity 15 and filling S650 the second mold cavity 17 are carried out simultaneously.
[0073] The first polymerizable material may have a high or low refractive index once cured. For example, the first polymerizable composition comprises thermoplastic materials such as polycarbonate (PC) or polymethyl metacrylate (PMMA), or thermoset materials such as thiourethane.
[0074] Likewise, the second polymerizable material may have a high or low refractive index once cured. For example, the second polymerizable composition comprises thermoplastic materials such as polycarbonate (PC) or polymethyl metacrylate (PMMA), or thermoset materials such as thiourethane.
[0075] The first polymerizable material and the second polymerizable material may be the same. Alternatively, the first polymerizable material and the second polymerizable material may be different.
[0076] Polymerizing S700 the first and second polymerizable materials may comprise polymerizing the first and second polymerizable materials simultaneously. Alternatively, Polymerizing S700 the first and second polymerizable materials may comprise successively polymerizing S710 the second polymerizable material and polymerizing S720 the first polymerizable material.
[0077] One embodiment of this method will be described with reference to Fig. 7. This embodiment of the method results in the mold assembly of Fig. 2.
[0078] In this embodiment, positioning S100 the wafer 23 at the first predetermined distance L1 from the first mold part 21 makes use of the positioning tool 40 as described above. The top part 41 of the positioning tool 40 engages the second wafer face 232 and the bottom part 42 of the positioning tool 40 engages the non-molding surface 212 of the first mold part 21 throughout the positioning S100 of the wafer 23 at the first predetermined distance L1 from the first mold part 21 .
[0079] After adhering the first adhesive tape 24 to the wafer edge 233 and the first mold edge 213, thus forming the partial mold assembly 200, the top part 41 and the bottom part 42 disengage from the partial mold assembly 200.
[0080] Then the top part 41 of the positioning tool 40 engages the second mold part 22 while the bottom part 42 of the positioning tool 40 engages the partial mold assembly 200 through the nonmolding surface 213 of the first mold part 21.
[0081] After adhering the second adhesive tape 26 to the assembly edge 203 and the second mold edge 223, thus forming the mold assembly 20, the top part 41 and the bottom part 42 disengage from the mold assembly 20 before removing S500 the tape tails, filling S600, S650 and polymerizing S700 are carried out.
[0082] Another embodiment of the method will be described with reference to Fig. 8. This embodiment of the method results in the mold assembly of Fig. 3.
[0083] In this embodiment, positioning S100 the wafer 33 at the first predetermined distance L1 from the first mold part 31 makes use of the positioning tool 40 as described above. The top part 41 of the positioning tool 40 engages the non-molding surface 312 of the first mold part 31 and the bottom part 42 of the positioning tool 40 engages the second wafer face 332 throughout the positioning S100 of the wafer 33 at the first predetermined distance L1 from the first mold part 31 .
[0084] After adhering the first adhesive tape 34 to the wafer edge 333 and the first mold edge 313, thus forming the partial mold assembly 300, the top part 41 and the bottom part 42 disengage from the partial mold assembly 300.
[0085] Then the top part 41 of the positioning tool 40 engages the partial mold assembly 300 through the non-molding surface 312 of the first mold part 31 while the bottom part 42 of the positioning tool 40 engages the non-molding surface 322 of the second mold part 32.
[0086] After adhering the second adhesive tape 26 to the assembly edge 303 and the second mold edge 323, thus forming the mold assembly 30, the top part 41 and the bottom part 42 disengage from the mold assembly 30 before removing S500 the tape tails, filling S600, S650 and polymerizing S700 are carried out.
Claims
Claims
1. A method for manufacturing an ophthalmic article, comprising:- positioning (S100) a wafer (13; 23) at a first predetermined distance (L1) from a first mold part (11 ; 21); wherein the wafer comprises a first wafer face (131 ; 231), a second wafer face (132; 232) opposite the first wafer face and a wafer edge (133; 233) joining the first and second wafer faces; wherein the first mold part (11 ; 21) comprises a first molding surface (111 ; 211) and a first mold edge (113; 213) extending from the first molding surface; wherein positioning results in the first wafer face facing the first molding surface;- adhering (S200) a first adhesive tape (14; 24) to both the wafer edge and the first mold edge through a first adhesive surface (141 ; 241) thereof; wherein the first adhesive surface extends between the wafer edge and the first mold edge; thereby forming a first mold cavity (15; 25) defined by the first wafer face, the first molding face and the first adhesive surface and obtaining a partial mold assembly (100; 200) with an assembly edge (101 ; 201);- positioning (S300) a second mold part (12; 22) having a second molding surface (121 ; 221) and a second mold edge (123; 223) extending from the second molding surface at a second predetermined distance (L2) to the partial mold assembly so that the second wafer face faces the second molding surface;- adhering (S400) a second adhesive tape (16; 26) to both the assembly edge and the second mold edge through a second adhesive surface (161 ; 261) thereof; wherein the second adhesive surface extends between the assembly edge and the second mold edge; thereby forming a second mold cavity (17; 27) defined by the second wafer face, the second molding face and the second adhesive surface and obtaining a full mold assembly (10; 20);- filling (S600) the first mold cavity with a first polymerizable material;- filling (S650) the second mold cavity with a second polymerizable material;- polymerizing (S700) the first and second polymerizable materials.
2. The method of claim 1 , wherein positioning the second mold part at the second predetermined distance from the partial mold assembly comprises centering the second mold part relatively to the partial mold assembly and bringing the second mold part to the second predetermined distance from the partial mold assembly.
3. The method of claim 2, wherein positioning the wafer at the first predetermined distance from the first mold part is carried out through a positioning tool comprising two parts: one top part adapted to engage with a convex surface and one bottom part adapted to engage with a concave surface; wherein each of the convex surface and the concave surface being one of the second face and the second molding surface.
4. The method of claim 3, wherein positioning the second mold part at the second predetermined distance from the partial mold assembly further comprises determining a third reference distance between the top part and the convex surface and determining a fourth reference distance between the bottom part and the concave surface.
5. The method of claim 4, wherein bringing the second mold part to the second predetermined distance from the partial mold assembly considers the third reference distance and the fourth reference distance.
6. The method of any one of claims 1 to 5, wherein filling the first mold cavity and filling the second mold cavity are carried out simultaneously or successively.
7. The method of any one of claims 1 to 6, wherein the first adhesive tape is applied around the wafer edge and the first mold edge from a first tape head to a first tape tail covering the first tape head; wherein the second adhesive tape is applied around the assembly edge and the second mold edge from a second tape head to a second tape tail covering the second tape head; and wherein the second tape head does not cover the first tape tail.
8. The method of claim 7, further comprising prior to filling the first mold cavity, removing the first tape tail and prior to filling the second mold cavity, removing the second tape tail, wherein removing the first tape tail and removing the second tape tail are carried out simultaneously or successively.
9. The method of any one of claims 1 to 8, wherein the wafer comprises microstructures.
10. A mold assembly comprising: a first mold part (11 ; 21) with a first molding surface (111 ; 211) and a first mold edge (113; 213) extending from the first molding surface; a second mold part (12; 22) with a second molding surface (121 ; 221) and a second mold edge (123; 223) extending from the second molding surface; a wafer (13; 23) with a first wafer face (131) facing the first molding surface at a first predetermined distance (L1) thereof , a second wafer face (132) opposite the first wafer face and facing the second molding surface at a second predetermined distance (L2) thereof, and a wafer edge (133) joining the first and second wafer faces; a first adhesive tape (14; 24) with a first adhesive surface (141 ; 241) adhering to the wafer edge and the first mold edge, the first adhesive surface extending between the wafer edge and the first mold edge; wherein the wafer, the first mold part and the first adhesive tape form together a partial mold assembly (100; 200) with an assembly edge (101 ; 201) and a first mold cavity (15; 25); the mold assembly further comprising: a second adhesive tape (16; 26) with a second adhesive surface (161 ; 261) adhering to the second mold edge and the assembly edge, the second adhesive surface extending between the second mold edge and the assembly edge, thus forming a second mold cavity (17; 27) with the wafer (13; 23) and the second mold part (12; 22).
11. The mold assembly of claim 10, wherein the first molding surface is a convex, respectively concave, surface and the second molding surface is a concave, respectively convex, surface; and wherein the first wafer face is a concave, respectively convex, surface and the second wafer face is a convex, respectively concave, surface.
12. The mold assembly of claim 10 or claim 11 , wherein the first adhesive tape runs around the wafer edge and the first mold edge from a first tape head to a first tape tail covering the first tape head; wherein the second adhesive tape runs around the assembly edge and the second mold edge from a second tape head to a second tape tail covering the second tape head; and wherein the second tape head does not cover the first tape tail.
13. The mold assembly of any one of claims 10 to 12, wherein the wafer comprises microstructures.
14. The mold assembly of claim 13, wherein the microstructures are myopia controlling microstructures or polarizing microstructures.
15. The mold assembly of claim 13 or claim 14, wherein the microstructures are at least one of microlenses and Fresnel rings.