METHOD FOR MANUFACTURING A TRANSPARENT PLASTIC LENS HAVING EMBEDDED DECORATIVE ELEMENTS

Abstract

The present invention relates to a method for manufacturing a molded ophthalmic article (1) comprising at least one decorative element (2), said method comprising: a- providing a mold (100) including a first mold element (102) and a second mold element (104) configured to cooperate together in a closed position to define a cavity (3); b- fixing said at least one decorative element (2) in said cavity (3); c- Casting a first molding liquid containing a monomer of a first transparent plastic material or injecting a transparent thermoplastic material into the cavity (3); d- hardening the first molding liquid comprising a monomer of a first transparent plastic material or cooling the transparent thermoplastic material and demolding the mold (100) to obtain a molded ophthalmic article (1) comprising at least one decorative element (2).

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a transparent plastic lens having at least one decorative element embedded within its mass of different shapes, sizes, materials and aesthetic effects. [Background technology]

[0002] The term clear plastic lens refers to a corrective lens or a lens without any corrective power. The lens can be used as eyeglasses, sunglasses for eye protection, goggles, visors or as a high-end fashion item.

[0003] Eyeglasses or sunglasses are usually intended to perform a medical function, in particular to protect the eye from solar radiation or from physical harm, to alleviate vision, or to correct the wearer's vision. In today's industry, the level of personalization and aesthetics required by end customers is becoming increasingly important. Therefore, expanding the available technologies to achieve new aesthetic effects creates value for customers.

[0004] In the modern industry, eyeglass frames are generally manufactured from polymers or metals using different manufacturing techniques. Many decorative techniques are known and used to decorate, engrave, and enrich the frames that make up eyeglasses. These techniques are scalable, reliable, and widely available.

[0005] However, for lenses, the possible portfolio of decoration techniques is limited. In particular, techniques that are easy to implement and offer a wide range of decoration possibilities for industrial applications are not readily available. In that case, such decoration must keep intact the main properties of the lens, whether corrected or not, such as transparency and optical quality, without interfering with the vision of the end user or impairing the mechanical properties of the lens.

[0006] Today, lens decoration often consists in applying interference filters to lenses to obtain a mirror effect or a specific tint in the transmission. Also, for example, branding is performed on the surface of lenses using several techniques, but the area of ​​interest is always limited to a small area. Examples of decoration techniques include inkjet printing, vacuum coating mirroring, pad printing, and laser marking. In any case, these types of decoration are limited in their application field, as they leave the aesthetic elements exposed to damage or generally do not provide a three-dimensional depth effect and are always taken from different business and industrial fields.

[0007] Considering these concepts, an innovative improvement in the field would be one that would protect the decoration and allow for the encapsulation of different 3D or 2D elements of different materials within the bulk of a transparent plastic lens, protecting them from external damage and thus improving the overall quality of the decorated optical lens, which would also unlock new aesthetic effects and combinations.

[0008] In the case of 3D elements, decorative elements such as diamonds, pearls, crystals, gemstones, metal flakes, and all other kinds of decorative and / or aesthetic elements with non-planar dimensions are contemplated, which may in particular vary in size, shape, color, material (both organic and inorganic) or with additional visual functions such as glittering, phosphorescent or photochromic effects.

[0009] In the case of 2D elements, decorative and / or aesthetic elements having planar dimensions are intended.

[0010] In the state of the art, methods for producing plastic lenses with embedded decorative elements are disclosed in EP 3730997 A1, US 2022155494 A1, EP 0390443 A1, JP 7-137158 A1, and EP 4057052 A1. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] European Patent Application Publication No. 3730997 [Patent Document 2] US Patent Application Publication No. 2022155494 [Patent Document 3] European Patent Application Publication No. 0390443 [Patent Document 4] Japanese Patent Application Publication No. 7-137158 [Patent Document 5] European Patent Application Publication No. 4057052 Summary of the Invention [Problem to be solved by the invention]

[0012] The present invention therefore aims to propose a method for producing a transparent plastic lens with at least one embedded decorative element according to claim 1. [Means for solving the problem]

[0013] Further features of the method are the subject of the dependent claims.

[0014] The characteristics and advantages of the method according to the invention will become more apparent from the following illustrative and non-limiting description, made with reference to the accompanying schematic drawings, in which: [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a scheme relating to a first embodiment according to the present invention. [Figure 2] Scheme for a first embodiment according to the invention, in which one of the mould elements is itself obtained by moulding a transparent plastic material. [Figure 3]A scheme for a first embodiment according to the invention, in which one of the mold elements is itself obtained by molding a transparent plastic material, and the ophthalmic article is subjected to a surface processing step. [Figure 4] A scheme for a first embodiment according to the invention, in which one of the mold elements is itself obtained by molding a transparent plastic material, and the ophthalmic article is subjected to a surface processing step. [Figure 5] 1 is a scheme relating to a second embodiment according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0016] The main concept of the proposed innovative method consists of the following essential steps: a- providing a mould 100 comprising a first mould element 102 and a second mould element 104 configured together in a closed position to define a cavity 3; b- fixing said at least one decorative element 2 in said cavity 3; c- Casting a first molding liquid or injecting a transparent thermoplastic material into the cavity 3, the first molding liquid comprising a monomer of a first transparent plastic material; d- hardening the first molding liquid comprising a monomer of a first transparent plastic material or cooling the transparent thermoplastic material and demolding the mold 100 to obtain a molded ophthalmic article 1 comprising at least one decorative element 2.

[0017] As used herein, the term "transparent" with respect to an optical element such as a plastic lens means that the optical element has a total light transmittance value of 60% or more, preferably 70% or more, and a haze value of 5% or less, preferably 4% or less, both measured according to ASTM D 1003.

[0018] According to the present invention, mold elements 102, 104 can be of various dimensions, bases and thicknesses (preferably between 0.5 mm and 10 mm). The thickness of the cavity obtained between mold elements 102, 104 determines the final thickness of the polymerized material, i.e., ophthalmic article 1 or mold element 102 or 104.

[0019] FIG. 1 summarizes the method according to a first embodiment, in which in step b at least one decorative element 2 is fixed on the first mold element 102 or the second mold element 104 by any mechanical or chemical means.

[0020] At least one decorative element can be arranged on the surface of the first mold element 102 or the second mold element 104 according to a specific decorative pattern, and then mounted, adhered or fixed by any mechanical, physical or chemical means.

[0021] This process can be automated or performed manually.

[0022] A polymer adhesive or any adhesive material of different nature can be used to support the placement and fixing of at least one decorative element on the surface of the first mold element 102 or on the second mold element 104.

[0023] At least one decorative element may optionally have a ready-to-use adhesive layer specifically designed to interact with the surface of the first mold element 102 or the second mold element 104.

[0024] Advantageously, as can be seen from Figures 2, 3 and 4, the second mould element 104 can be obtained by moulding a second transparent plastic material, which moulding can comprise a step of casting and hardening a second moulding liquid comprising a monomer of the second transparent plastic material, after which at least one decorative element 2 can be fixed in the second mould element 104 in step b.

[0025] Alternatively, the second mold element 104 can be manufactured through an injection process of a transparent thermoplastic material in a mold.

[0026] Specifically, for the casting process, which is the preferred manufacturing method, a glass mold consisting of two distinct glass lenses (ie, mold elements) is assembled with an elastomeric band support or adhesive tape support.

[0027] The second transparent plastic material may be prepared starting from the same molding liquid used for the first transparent plastic material, or from a different molding liquid containing a monomer. In one embodiment, the same molding liquid is used to obtain the first and second transparent plastic materials.

[0028] When prepared by injection molding, the second transparent plastic material may be obtained using the same or a different thermoplastic material as the thermoplastic material used to prepare the first transparent plastic material. In one embodiment, the same thermoplastic material is used to obtain the first and second transparent plastic materials.

[0029] The glass lenses used in the mold assembly can be spherical, toric, cylindrical, flat, curved, or any possible geometric shape. The mold is then filled with a reactive mixture of monomers.

[0030] Exemplary monomers suitable as first and second molding liquids for the production of cast optical articles include CR-39 and Trivex™ manufactured by PPG Industries and MR-7, MR-8, MR-10, MR-160DG manufactured by Mitsui Chemicals, Inc.

[0031] Typical thermoplastic materials suitable for preparing the first and second transparent plastic materials include polycarbonates and polyamides (amorphous or semi-crystalline).

[0032] The mold is then subjected to a thermal or photochemical process that causes the curing process of the monomer mixture.

[0033] Finally, after a demolding process, the second mould element 104 is obtained.

[0034] Essentially, in this embodiment, a transparent plastic lens is used as a mold element, which can have high mechanical and optical properties because it is prepared separately in a mold consisting of two mold elements, for example made of glass, and can therefore be used as an optical element (half lens) of the final ophthalmic article, i.e., the mold element is an integral part of the final ophthalmic article.

[0035] If the second mould element 104 is made of a transparent plastic material, in one embodiment at least one decorative element (2) is mounted on said optical element.

[0036] Considering the many possible combinations of materials and shapes possible with this innovative decorative method, additional steps can be proposed to promote quality and compatibility between materials or to create specific aesthetic effects.

[0037] The second mould element 104 carrying at least one decorative element can be treated using different surface treatment techniques such as chemical etching of the surface, chemical functionalisation, plasma etching, corona etching or general vacuum physico-chemical surface treatment and / or deposition of varnishes / primers or inks.

[0038] Alternatively, only at least one decorative element may be subjected to the same surface treatment before being mounted on the surface of the second mold element 104 .

[0039] In both cases, a surface treatment, in particular plasma etching, is advantageously carried out when the decorative element is made of an inorganic material, or at least when its outer surface is made of an inorganic material, and in fact it improves the compatibility of the decorative element with the plastic material from which the ophthalmic article is made.

[0040] If a surface treatment is performed on the second mould element 104, it improves its compatibility with the first transparent plastic material or the first transparent thermoplastic material.

[0041] Advantageously, the hardening of the second molding liquid comprising a monomer of a second transparent plastic material is incomplete so as to form a chemical bond between the second mold element 104 and the at least one decorative element 2 during hardening in step d.

[0042] The second mould element 104 (with at least one decorative element attached to its surface according to a specific pattern or positioning) can be used as a structural element of the second mould, ie the mould in step d.

[0043] When a plastic lens is used as the second mold element 104 supporting the decorative element in combination with the first mold element 102, for example made of glass, the method of the present invention results in an ophthalmic article 1 comprising two optical elements, i.e., half lenses, bonded together, in which the decorative element is embedded. Indeed, hardening of the first molding liquid, which comprises a monomer, produces a first transparent plastic material that firmly adheres to the plastic material of the second mold element 104. During the demolding operation, the first mold element 102 is removed, and the ophthalmic article 1 made of the two half lenses (i.e., the front lens and the back lens) is stuck together, with the decorative element embedded.

[0044] In one embodiment, the molding liquids containing monomers (i.e., polymerizable compositions) used to prepare the first and second transparent materials have the same or similar composition to enhance compatibility between the two half lenses and reduce the risk of them becoming dislodged.

[0045] In one embodiment, the second molding liquid (i.e., second mold element 104) containing the monomer is not fully cured to obtain a partially cured second transparent plastic material. The partially cured material contains residual portions of the original reactive functional species (e.g., ethylenically unsaturated groups, isocyanate groups, amine groups) that can polymerize during a subsequent cure cycle of the first molding liquid, strengthening the adhesion of the two half-lens components.

[0046] Similar advantages for bonding two optical elements are obtained when the transparent plastic material is a transparent thermoplastic material prepared by injection molding.

[0047] The embodiment in which a plastic lens is used as the second mold element also has several advantages in terms of the aesthetic effects that can be obtained for the ophthalmic article. Because the ophthalmic article comprises a first half lens (e.g., a front lens) and a second half lens (e.g., a rear lens), various aesthetic appearances of the ophthalmic article can be designed by imparting a desired appearance to one or both optical elements (i.e., half lenses). For example, in one embodiment, one of the two half lenses (e.g., the second mold element) can be colored, for example, by in-situ coloring or sublimation techniques, while the other (e.g., the first transparent plastic material) remains transparent. The ophthalmic article thus obtained is suitable as a sunglass lens with an enhanced appearance of decorative elements compared to lenses made with a single in-situ colorant by known techniques. Indeed, if the colored half lens is the rear lens (i.e., the one facing the wearer's eye) and the transparent lens is the front lens, the decorative elements are more clearly visible to an observer looking at the wearer.

[0048] FIG. 5 summarizes a method according to a second embodiment of the invention, in which in step b at least one decorative element 2 is mounted on a supporting polymer thin wafer so as to be fixed in said cavity 3 .

[0049] Advantageously, the wafer may be a transparent carrier film or a functional carrier film with light absorbing or light reflecting properties, or a combination thereof.

[0050] Its thickness can vary between 20 microns and 0.8 millimeters.

[0051] The polymeric materials used in such wafers can vary and are known to those skilled in the art.

[0052] The wafer is placed inside a cavity mold that is fixed directly onto the surface of the first mold element 102 or onto the second mold element 104, or it can be held in place at a fixed distance from the cavity surface using a suitable elastomeric gasket or adhesive tape.

[0053] The main advantage of the method according to the second embodiment is that only one filling of the monomer mixture inside the mold is necessary, since the monomer fills the cavities on both sides of the wafer and thus encapsulates the entire support wafer with at least one decorative element.

[0054] Advantageously, according to the first or second embodiment, the method further comprises, before step b, a surface treatment step of said at least one decorative element 2, said surface treatment step being selected from one or more of varnish / primer, inking, chemical etching of the surface, chemical functionalization, plasma etching, corona etching or vacuum physico-chemical surface treatment and / or deposition.

[0055] After fixing at least one decorative element 2 inside the cavity 3 according to the first or second embodiment, the molding in steps c and d of the present invention is carried out in the same way as described above for molding the second transparent plastic material to obtain the second mold element 104.

[0056] A molding liquid comprising a monomer of a transparent plastic material is cast inside the cavity 3, the liquid can have the same, similar or different chemical composition as the second transparent plastic material.

[0057] After a similar curing and demolding process, the final molded ophthalmic article 1 is obtained with at least one decorative element encapsulated and protected within its mass.

[0058] Alternatively, the molding in steps c and d of the present invention may be performed by heating and injecting a transparent thermoplastic material into the cavity, the type of transparent thermoplastic material and the operating conditions being well known to those skilled in the art.

[0059] The transparent thermoplastic material is then cooled and the mold 100 is opened, yielding the final molded ophthalmic article 1 with the at least one decorative element encapsulated and protected within its mass.

[0060] Preferably, and as can be seen in Figures 3 and 4, the molded ophthalmic article 1 can be subjected to a surface processing step to reduce its thickness and, optionally, to obtain optical power.

[0061] Alternatively, the molded ophthalmic article 1 is adapted to have a predetermined thickness without the need for a surface processing step.

[0062] At least one decorative element in all of the methods described may vary in size, shape, color, material (both organic and inorganic) or may have additional visual functions such as glittering, phosphorescent or photochromic effects.

[0063] The at least one decorative element may be two-dimensional, comprising a resin layer applied by pad printing or inkjet, or may be three-dimensional in space, such as a cabochon or other jewelry element. Depending on the color and treatment of the second mold element 104, different and new aesthetic effects can be achieved.

[0064] Preferably, the decorative elements are made of inorganic materials such as diamonds, pearls, crystals, gemstones, metal flakes, glass beads, or organic materials such as plastics. The inorganic materials can optionally be coated with a coating film, such as a film deposited by physical vapor deposition (PVD), a decorative paint, etc. The decorative elements can be 2D or 3D elements.

[0065] In particular, the thickness of the at least one decorative element should be at most about 80% of the thickness d of the ophthalmic article lens 1 at the location where the at least one decorative element is embedded.

[0066] Preferably, the at least one decorative element may be fixed using an adhesive material, more preferably an adhesive material comprising a cyanoacrylate or acrylic compound.

[0067] The at least one decorative element may be transparent or may exhibit a refractive index similar or identical to that of the transparent plastic material used to manufacture the molded ophthalmic article, and is incapable of inducing a local change in the visible light transmission of the molded ophthalmic article 1. In this case, the at least one decorative element 2 may be disposed over the entire surface of the molded ophthalmic article.

[0068] Conversely, if at least one decorative element is not transparent but visible, or if at least one decorative element 2 may induce a local change in the visible light transmission of the molded ophthalmic article 1, its positioning on the surface of the ophthalmic article should be designed with care.

[0069] A specific central area of ​​the lens, which is a 30 mm circle around the optical center of the lens according to ISO 12312 2022, must not contain any decoration in order to maintain the end user's visual comfort without any impairment.

[0070] The transparent plastic material, the second transparent plastic material and / or the supporting polymer thin wafer may exhibit additional functionality and properties, including, but not limited to, for example, a photochromic layer, a contrast enhancing filter, a vacuum coated surface, an anti-reflective coating, or a combination thereof.

[0071] Advantageously, a single monomer mixture can be used instead of a reactive monomer mixture.Any thermoset or thermoplastic material that can normally be processed without degrading the quality of the final product.

[0072] Typically, when using thermoplastic materials, the injection molding process will be the preferred industrial method for filling the mold.

[0073] In that case, the lens molds can be made of glass or steel with the appropriate grade and relative surface treatment known to those skilled in the art.

[0074] Alternatively, in the case of injection molding, the mold is held closed by the mechanical clamping force of the injection molding machine.

[0075] For use with eyeglasses or sunglasses, the outer edge is shaped according to the desired shape of the eyeglass or sunglasses frame.

[0076] Another object of the invention is a molded ophthalmic article 1 obtained by the method according to the invention.

[0077] By ophthalmic article 1 is meant a finished or semi-finished corrective lens or (plano lens) suitable for being attached to a frame, such as a spectacle frame, goggles, a mask or a visor intended to be placed in front of the eyes to form a visual protection screen.

[0078] At this stage, the ophthalmic article 1, which has not undergone any further processing, can be considered a lens blank element.

[0079] In this context, treatments that impart additional functionality, either alone or in combination, from the following non-exhaustive list, are not considered additional layers: impact resistance, scratch resistance, abrasion resistance, anti-reflective, anti-smudge, anti-fog, anti-static.

[0080] These additional functions can be performed according to conventional methods (dipping, vacuum deposition, spin coating, spray coating, etc.).

[0081] Some of these treatments may be applied before or after fabrication of the final ophthalmic article.

[0082] The material of the decorative object 2 may be chosen to be compatible with a chosen molding process, which may be an injection molding process or a cast molding process.

[0083] Advantageously, depending on the molding process chosen, it shall also be chosen not to stare, in order to avoid the formation of bubbles during injection or during hardening in the case of casting.

[0084] The extracted ophthalmic article 1 can be used as is, can be molded into the required shape, or can be subjected to one or more additional treatments, such as the deposition of a hard coat treatment, an anti-reflective treatment and / or a mirroring treatment, as described above.

Claims

1. A method for making a molded ophthalmic article (1) comprising at least one decorative element (2), comprising: providing a mold (100) including a first mold element (102) and a second mold element (104) configured to cooperate together in a closed position to define a cavity (3); b) fixing said at least one decorative element (2) in said cavity (3); c. Casting a first molding liquid containing a monomer of a first transparent plastic material or injecting a transparent thermoplastic material into the cavity (3); and d. hardening the first molding liquid comprising a monomer of a first transparent plastic material or cooling the transparent thermoplastic material, and demolding the mold (100) to obtain a molded ophthalmic article (1) comprising at least one decorative element (2).

2. 10. The method for manufacturing a molded ophthalmic article (1) according to claim 1, wherein the at least one decorative element (2) in step b) is fixed onto the first mold element (102) or the second mold element (104) by any mechanical or chemical means.

3. 3. The method of claim 1 or 2, wherein the second mold element (104) is an optical element made of a second transparent plastic material.

4. 4. The method for manufacturing a molded ophthalmic article (1) according to claim 3, wherein in step b, said at least one decorative element (2) is mounted on at least said second mold element (104).

5. The second die element (104) comprises: - casting and curing a second molding liquid comprising a monomer of said second transparent plastic material, or - A method for producing a molded ophthalmic article (1) according to claim 3 or 4, which is an optical element obtained by injecting and cooling a transparent thermoplastic material.

6. The method for producing a molded ophthalmic article (1) according to any one of claims 3 to 5, wherein the second transparent plastic material is a partially cured polymeric material containing polymerizable functional groups.

7. The method for manufacturing a molded ophthalmic article (1) according to any one of claims 3 to 6, wherein after the demolding step, the mold element (104) is part of the molded ophthalmic article.

8. 2. The method for manufacturing a molded ophthalmic article (1) according to claim 1, wherein in step b, said at least one decorative element (2) is mounted on a supporting polymer thin wafer so as to be fixed inside said cavity (3).

9. 9. The method of claim 8, wherein the supporting polymer thin wafer is a transparent carrier film, or a functional film having light absorbing or reflecting properties, or a combination thereof.

10. 10. The method for producing a molded ophthalmic article (1) according to any one of claims 1 to 9, further comprising a surface treatment step of said at least one decorative element (2) before step b, said surface treatment step being selected from one or more of varnish / primer, inking, chemical etching of said surface, chemical functionalization, plasma etching, corona etching or vacuum physico-chemical surface treatment and / or deposition.

11. 11. A method for manufacturing a molded ophthalmic article (1) according to any one of claims 1 to 10, wherein the molded ophthalmic article (1) is subjected to a surface processing step to reduce its thickness and optionally to obtain optical power.

12. The method of any one of claims 1 to 10, wherein the molded ophthalmic article (1) is adapted to have a predetermined thickness without a surface processing step.

13. 13. The method of manufacturing a molded ophthalmic article (1) according to any one of claims 1 to 12, wherein the at least one decorative element adds visual functionality selected from a glitter effect, a phosphorescent effect, or a photochromic effect, or a combination thereof.

14. 14. The method for manufacturing a molded ophthalmic article (1) according to any one of claims 1 to 13, wherein the at least one decorative element has a maximum thickness of about 80% of the thickness of the ophthalmic article lens (1) to which the at least one decorative element (2) is fixed.

15. 15. The method of manufacturing a molded ophthalmic article (1) according to any one of claims 1 to 14, wherein the first transparent plastic material, the second transparent plastic material and / or the supporting polymer thin wafer have additional functionality and properties selected from photochromic layers, contrast enhancing filters, vacuum coated surfaces, anti-reflective coatings and combinations thereof.

16. 16. A method for producing a moulded ophthalmic article (1) according to any one of claims 1 to 15, wherein in step b, said at least one decorative element (2) is fixed using an adhesive material, preferably comprising a cyanoacrylate or an acrylic compound.

17. 17. A method for producing a molded ophthalmic article (1) according to any one of claims 1 to 16, wherein the at least one decorative element (2) is transparent or exhibits a refractive index similar or identical to that of the transparent plastic material, the at least one decorative element (2) does not have the ability to induce a local change in the visible light transmission of the molded ophthalmic article (1), and the at least one decorative element (2) is arranged over the entire surface of the molded ophthalmic article (1).

18. 14. The method for producing a molded ophthalmic article (1) according to any one of claims 1 to 13, wherein the at least one decorative element (2) is visible or capable of inducing a local change in the visible light transmission of the molded ophthalmic article (1), and the at least one decorative element (2) is arranged across the surface of the molded ophthalmic article (1) apart from a 30 mm circle around the optical center of the molded ophthalmic article (1).

19. A molded ophthalmic article (1) obtainable by the method according to any one of claims 1 to 18.

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