Method for producing transparent plastic lens with embedded decorative element

Abstract

The invention relates to a method for manufacturing a molded ophthalmic article (1) comprising at least one decorative element (2), said method comprising the steps of: a-providing a mold (100) comprising a first mold element (102) and a second mold element (104), the first mold element and the second mold element being configured to cooperate together in a closed position to define a cavity (3); b-fixing the at least one decorative element (2) inside the cavity (3); c-casting a first moulding liquid comprising a monomer of a first transparent plastic material or injecting a transparent thermoplastic material into the interior of the cavity (3); d-curing said first moulding liquid comprising a monomer of a first transparent plastic material or cooling said transparent thermoplastic material, and demoulding said mould (100) to obtain a moulded ophthalmic article (1) comprising at least one decorative element (2).

Description

[0001] The invention relates to a method for producing a transparent plastic lens having at least one integral embedded decorative element of varying shape, size, material and aesthetic effect.

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

[0003] Glasses or sunglasses are often used for medical functions, specifically to protect the eyes from solar radiation or physical damage, to provide visual acuity, or to correct the wearer's vision. In today's industry, the level of personalization and aesthetics demanded by end customers is becoming increasingly important. To this end, expanding the available technologies to achieve new aesthetic effects creates value for customers.

[0004] In the modern industry, eyeglass frames are typically made from polymers or metals using various manufacturing techniques. Numerous 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, the possible combinations of decoration techniques for lenses are limited. In particular, technologies that are easy to implement and offer a wide range of decorative possibilities for industrial applications are not readily available. Furthermore, such decorations must preserve the key properties of the lens (whether corrective or not), such as transparency and optical quality, without interfering with the end user's vision or compromising the mechanical properties of the lens.

[0006] Today, lens decoration typically involves applying interference filters, for example, to the lens to achieve a mirror effect or a specific tint in transmission. Similarly, branding, for example, can be applied to the lens surface using a variety of techniques, but the area of interest is always limited to a small area. Examples of decoration techniques include inkjet printing, vacuum coating of mirror reflections, pad printing, and laser marking. In any case, these types of decoration render the aesthetic element susceptible to damage or generally fail to create a three-dimensional depth effect. Furthermore, their application areas are limited, as they often originate from different companies and industry sectors.

[0007] Taking these concepts into account, an innovative improvement in this field would be protective decoration, allowing different 3D or 2D elements of different materials to be encapsulated inside the block of a transparent plastic lens, thus protecting them from external damage and thus improving the overall quality of the decorated optical lens. This would also unlock new aesthetic effects and combinations.

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

[0009] By 2D elements, decorative and / or aesthetic elements having planar dimensions are intended.

[0010] In the prior art, methods for producing plastic lenses with embedded decorative elements are disclosed in EP 3730997 A1, US 2022155494 A1, EP 0390443 A1, JPH 07137158 A and EP 4057052 A1.

[0011] The object of the present invention is therefore to propose a method for producing a transparent plastic eyeglass lens having at least one embedded decorative element as claimed in claim 1 .

[0012] Further characteristics of the method are the subject matter of the dependent claims.

[0013] The characteristics and advantages of the method according to the invention will become more apparent from the following illustrative and non-limiting description, with reference to the accompanying schematic drawings, in which:

[0014] - Figure 1 is a solution related to the first embodiment according to the present invention,

[0015] - Figure 2 is a solution related to the first embodiment according to the invention, wherein one of the mould elements is itself obtained by moulding a transparent plastic material,

[0016] - Figure 3 and Figure 4 is a solution related to the 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 treatment step;

[0017] - Figure 5 This is a solution related to the second embodiment according to the present invention.

[0018] The main concept of the proposed innovative approach includes the following basic steps:

[0019] a- providing a mold 100 comprising a first mold element 102 and a second mold element 104 configured to cooperate together in a closed position to define a cavity 3,

[0020] b- fixing said at least one decorative element 2 inside said cavity 3,

[0021] c- pouring a first molding liquid comprising a monomer of a first transparent plastic material into or injecting a transparent thermoplastic material into the interior of the cavity 3,

[0022] d—curing 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 .

[0023] 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 equal to or higher than 60%, preferably equal to or higher than 70%, and a haze value equal to or lower than 5%, preferably equal to or lower than 4%, both of which are measured according to ASTM D 1003.

[0024] According to the present invention, mold elements 102, 104 can have variable dimensions, bases, and thicknesses (preferably, thicknesses ranging from 0.5 mm up to 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).

[0025] Figure 1 This concludes the method according to the first embodiment, wherein, in step b, at least one decorative element 2 is fixed to the first mould element 102 or to the second mould element 104 by any mechanical or chemical means.

[0026] At least one decorative element may be placed on the surface of first mold element 102 or on second mold element 104 in a specific decorative pattern and then anchored or glued or fixed by any mechanical, physical or chemical means.

[0027] This process can be automated or can be performed manually.

[0028] Polymer glues of different nature or any adhesive material may be used to support the placement and fixing of at least one decorative element onto the surface of first mold element 102 or onto second mold element 104 .

[0029] In some cases, at least one decorative element may present a ready-to-use adhesive layer specifically designed to interact with a surface of first mold element 102 or second mold element 104 .

[0030] Advantageously, and as from Figure 2 、 Figure 3 and Figure 4As can be seen, the second mold element 104 can be obtained by molding a second transparent plastic material. This molding of the second transparent plastic material can include the steps of pouring and curing a second molding liquid comprising a monomer of the second transparent plastic material. Thereafter, in step b, at least one decorative element 2 can be fixed to the second mold element 104.

[0031] Alternatively, the second mold element 104 may be manufactured by an injection process of injecting a transparent thermoplastic material into the interior of the mold.

[0032] 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 support from an elastomeric band or with support from an adhesive tape.

[0033] The second transparent plastic material may be prepared starting from a moulding liquid comprising monomers which is the same as or different from the moulding liquid used for the first transparent plastic material.In one embodiment the same moulding liquid is used to obtain the first transparent plastic material and the second transparent plastic material.

[0034] When produced by injection moulding, the second transparent plastic material may be obtained using the same or different thermoplastic material than the thermoplastic material used to produce the first transparent plastic material.In one embodiment, the first and second transparent plastic materials are obtained using the same thermoplastic material.

[0035] The glass lens used for the mold assembly can be spherical, toric, cylindrical, flat, curved, or have any conceivable geometry.The mold is then filled with a reactive mixture of monomers.

[0036] Typical monomers used to make cast optical articles and suitable as the first and second molding liquids include CR-39 and Trivex™ manufactured by PPG Industries and MR-7, MR-8, MR-10, MR-160DG manufactured by Mitsui Chemicals.

[0037] Typical thermoplastic materials suitable for preparing the first transparent plastic material and the second transparent plastic material include polycarbonate and polyamide (amorphous or semi-crystalline).

[0038] The mold then undergoes a thermal or photochemical process that triggers the curing process of the monomer mixture.

[0039] Finally, after the demoulding process, a second mold element 104 is obtained.

[0040] Essentially, in this embodiment, a transparent plastic lens is used as a mold element. Since this plastic lens is produced separately, for example in a mold consisting of two mold elements made of glass, it can have high mechanical and optical properties and can therefore be used as an optical element (half-lens) of a final ophthalmic product, i.e., the mold element is an integral part of the final ophthalmic product.

[0041] When second mold member 104 is made of a transparent plastic material, in one embodiment, at least one decorative element is anchored to the optical element.

[0042] Taking into account the many possible combinations of materials and shapes envisaged in this innovative decoration method, additional steps can be proposed in order to improve the quality and compatibility between materials or to produce a specific aesthetic effect.

[0043] The second mold element 104 with at least one decorative element can be treated using different surface treatment techniques like varnish / primer or ink application via different methods, chemical etching of the surface, chemical functionalization, plasma etching, corona etching or general vacuum physico-chemical surface treatment and / or deposition.

[0044] Alternatively, only at least one decorative element may be subjected to the same surface treatment before being anchored on the surface of the second mold element 104 .

[0045] In both cases, advantageously, when the decorative element is made of inorganic material or at least its outer surface is made of inorganic material, a surface treatment, in particular plasma etching, is performed. In fact, it improves the compatibility of the decorative element with the plastic material forming the ophthalmic article.

[0046] When the second mold member 104 is surface treated, it improves the compatibility of the second mold member with the first transparent plastic material or the first transparent thermoplastic material.

[0047] Advantageously, the curing of the second moulding liquid comprising a monomer of a second transparent plastic material is incomplete so as to form a chemical bond between the second mould element 104 and the at least one decorative element 2 during the curing in step d.

[0048] The second mould element 104 (on the surface of which at least one decorative element is anchored in a specific pattern or position) may be used as a structural element of the second mould (ie the mould in step d).

[0049] When a plastic lens is combined with a first mold element 102, for example, made of glass, and a second mold element 104, which serves as a support for a decorative element, the method of the present invention results in an ophthalmic article 1 comprising two optical elements (i.e., half lenses) joined together, with the decorative element embedded in the ophthalmic article. In practice, the solidification of the first molding liquid, comprising 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, leaving the ophthalmic article 1 made of the two half lenses (i.e., the front lens and the back lens) bonded together and with the decorative element embedded in the ophthalmic article.

[0050] In one embodiment, the molding liquids (ie, polymerizable compositions) including monomers used to prepare the first and second transparent materials have the same or similar composition in order to improve the compatibility between the two half-lenses and reduce the risk of separation of the two half-lenses.

[0051] In one embodiment, the second molding liquid (i.e., second mold element 104) comprising monomers is not fully cured to obtain a partially cured second transparent plastic material. The partially cured material includes remnants of the original reactive functional species (e.g., ethylenically unsaturated groups, isocyanate groups, amine groups), which can be polymerized during a subsequent curing cycle of the first molding liquid, thereby enhancing the adhesion of the two half-lens components.

[0052] Similar advantages are achieved with regard to the adhesion of the two optical elements when the transparent plastic material is a transparent thermoplastic material produced by injection molding.

[0053] Embodiments in which a plastic lens is used as the second mold element also offer several advantages in terms of the aesthetic effects that can be achieved with the ophthalmic article. Since the ophthalmic article comprises a first lens half (e.g., the front lens) and a second lens half (e.g., the back lens), various aesthetic designs can be designed for the ophthalmic article by imparting a desired appearance to one or both optical elements (i.e., the lens halves). For example, in one embodiment, one of the two lens halves (e.g., the second mold element) can be tinted, for example, by integral tinting or by a sublimation technique, while the other lens half (e.g., the first transparent plastic material) remains transparent. The ophthalmic article thus obtained is suitable as a sunglass lens, and the appearance of the decorative element is enhanced compared to lenses made from a single, integrally tinted body according to known techniques. Indeed, if the tinted lens half is the back lens (i.e., the lens half facing the wearer's eye) and the transparent lens is the front lens, the decorative element will therefore be more clearly visible to an observer looking at the wearer.

[0054] Figure 5A method according to a second embodiment of the invention is summarized in which, in step b, at least one decorative element 2 is anchored to a supporting polymer thin wafer so as to be fixed inside said cavity 3 .

[0055] Advantageously, the wafer may be a transparent carrier film, or a functional carrier film having light absorbing or light reflecting properties, or a combination of these.

[0056] The thickness of the wafer can vary from 20 microns to 0.8 mm.

[0057] The polymeric materials used for such wafers can vary and are known to those skilled in the art.

[0058] The wafer is positioned inside the cavity mold, either directly on the surface of the first mold member 102 or on the second mold member 104, or may be held at a distance from the cavity surface using suitable elastic pads or tape.

[0059] The main advantage of the method according to the second embodiment is that only one monomer mixture needs to be filled inside the mold, since the monomer will fill the cavity on both sides of the wafer, thus encapsulating the entire support wafer with the at least one decorative element.

[0060] Advantageously, according to the first or second embodiment, the method further comprises, before step b, a step of surface treatment of the at least one decorative element 2, wherein the surface treatment step is selected from one or more of the following: varnish / primer, ink application, chemical etching of the surface, chemical functionalization, plasma etching, corona etching or vacuum physical-chemical surface treatment and / or deposition.

[0061] 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 invention is performed in the same way as molding the second transparent plastic material to obtain the second mold element 104 as described above.

[0062] A molding liquid comprising a single body of transparent plastic material is poured into the interior of the cavity 3 , wherein the liquid may have the same, similar or different chemical composition as the second transparent plastic material.

[0063] After a similar curing and demoulding process, the final molded ophthalmic article 1 is obtained, wherein the at least one decorative element is entirely encapsulated and protected.

[0064] Alternatively, the molding in steps c and d of the present invention can be performed by heating a transparent thermoplastic material and injecting the transparent thermoplastic material into the interior of the cavity. The type of transparent thermoplastic material and the operating conditions are known to those skilled in the art.

[0065] Afterwards, the transparent thermoplastic material is cooled and the mold 100 is opened, obtaining the final molded ophthalmic article 1 , wherein the at least one decorative element is entirely encapsulated and protected.

[0066] Preferably, and as can be Figure 3 and Figure 4 As shown in , the molded ophthalmic article 1 may be subjected to surface treatment steps to reduce its thickness and optionally acquire optical power.

[0067] Alternatively, the molded ophthalmic article 1 is adapted to have a predefined thickness without requiring a surface treatment step.

[0068] At least one decorative element in all the methods described may vary in size, shape, color, material (both organic and inorganic) or have an additional visual function like a photoluminescent, phosphorescent or photochromic effect.

[0069] At least one decorative element may be two-dimensional, comprising a resin layer applied by pad printing or inkjet, or may be spatially three-dimensional, such as a cabochon or other jewelry element.Depending on the color and treatment of second mold element 104, different and new aesthetic effects may be achieved.

[0070] Preferably, the decorative element is made of an inorganic material (such as diamonds, pearls, crystals, gemstones, metal flakes, glass beads) or an organic material (such as plastic). The inorganic material may optionally be coated with a coating film, such as a film deposited by physical vapor deposition (PVD), decorative painting, etc. The decorative element may be a 2D element or a 3D element.

[0071] In particular, the thickness of the at least one decorative element should be at most approximately 80% of the thickness d of the ophthalmic article lens 1 at the location where the at least one decorative element is embedded.

[0072] Preferably, at least one decorative element is fixable using an adhesive material, more preferably the adhesive material comprises a cyanoacrylate or acrylic compound.

[0073] The at least one decorative element may be transparent or exhibit a refractive index that is similar or the same as the refractive index of the transparent plastic material used to make the molded ophthalmic article, and it may not have the ability to cause a localized change in the visible light transmittance of the molded ophthalmic article 1. In this case, the at least one decorative element 2 may be placed across the entire surface of the molded ophthalmic article.

[0074] In contrast, where at least one decorative element is opaque and visible, or where at least one decorative element 2 can cause a localized change in the visible light transmittance of the molded ophthalmic article 1 , the positioning of the at least one decorative element on the surface of the ophthalmic article should be carefully designed.

[0075] A specific central area of the lens (a 30 mm circle around the optical center of the lens according to ISO 12312 2022) must be free of any decoration in order to keep the visual comfort of the end user unaffected.

[0076] The transparent plastic material, the second transparent plastic material and / or the supporting polymer thin wafer may exhibit additional functions and properties, such as but not limited to: a photochromic layer, a contrast enhancement filter, a vacuum coated surface, an anti-reflective coating, or a combination thereof.

[0077] Advantageously, a single monomer mixture may be used instead of a reactive monomer mixture.Any thermosetting or thermoplastic material that can be processed normally without reducing the quality of the final product may be used.

[0078] Typically, when using thermoplastic materials, an injection molding process will be the preferred industrial method for filling the mold.

[0079] In this case, the lens molds can be made from glass or steel with appropriate grades and relative surface treatments known to those skilled in the art.

[0080] Furthermore, in the alternative case of injection molding, the mold will be held closed by the mechanical clamping force of the injection molding equipment.

[0081] For use in spectacles or sunglasses, the outer edge is shaped according to the desired shape of the frame of the spectacles or sunglasses.

[0082] Another object of the present invention is a molded ophthalmic article 1 obtained by the process according to the invention.

[0083] Ophthalmic article 1 refers to a finished or semi-finished corrective lens or (plano lens) suitable for mounting in a frame (such as a spectacle frame), goggles, a mask, or a visor intended to be placed in front of the eye and form a vision protection screen.

[0084] At this stage, the ophthalmic article 1, which has not yet undergone further processing, may be considered a Lens Precursor element.

[0085] In this context, the following non-exhaustive list of treatments imparting additional functionality, either alone or in combination, are not considered to be additional layers: shockproof, anti-scratch, anti-abrasion, anti-reflective, anti-fouling, anti-fog, anti-static.

[0086] These additional functions can be realized according to conventional methods (immersion, vacuum deposition, spin coating, spray coating, etc.).

[0087] Several of these treatments may be applied before or after the final ophthalmic product is produced.

[0088] The material of the decorative object 2 may be selected to be compatible with the chosen moulding process, which may be an injection moulding process or a casting moulding process.

[0089] Advantageously, one should also choose not to relax monitoring in order to avoid the formation of bubbles during injection or, in the case of pouring, during solidification (depending on the chosen molding process).

[0090] The removed ophthalmic article 1 can be used as is, shaped into the desired form, or undergo one or several additional treatments as described above, like deposition of a hard coating treatment, an anti-reflective treatment and / or a specular reflective treatment.

Claims

1. A method for producing a molded ophthalmic article (1) comprising at least one decorative element (2), the method comprising the following steps: a. providing a mold (100), the mold comprising a first mold element (102) and a second mold element (104), the first mold element and the second mold element being configured to cooperate together in a closed position to define a cavity (3), b. fixing the at least one decorative element (2) inside the cavity (3), c. pouring a first molding liquid comprising a monomer of a first transparent plastic material into or injecting a transparent thermoplastic material into the interior of the cavity (3), d. solidifying the first molding liquid comprising a monomer of a first transparent plastic material or cooling the transparent thermoplastic material, and demoulding the mold (100) to obtain a molded ophthalmic article (1) comprising at least one decorative element (2).

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

3. A method for producing a molded ophthalmic article (1) according to claim 1 or 2, wherein: - The second mould element (104) is an optical element made of a second transparent plastic material.

4. The method for producing a molded ophthalmic article (1) according to claim 3, wherein In step b, the at least one decorative element (2) is anchored at least to the second mould element (104).

5. The method for producing a molded ophthalmic article (1) according to claim 3 or 4, wherein The second mold element (104) is an optical element obtained by: - pouring and curing a second molding liquid comprising a monomer of the second transparent plastic material, or -Injection and cooling of transparent thermoplastic material.

6. A 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 polymer material including polymerizable functional groups.

7. A method for producing 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. The method for producing a molded ophthalmic article (1) according to claim 1, wherein In step b, said at least one decorative element (2) is anchored to a supporting polymer thin wafer so as to be fixed inside said cavity (3).

9. The method for producing a molded ophthalmic article (1) according to claim 8, wherein The supporting polymer thin wafer is a transparent carrier film, or a functional film having light absorbing or light reflecting properties, or a combination thereof.

10. The method for producing a molded ophthalmic article (1) according to any one of the preceding claims, further comprising, before step b, a step of surface treating the at least one decorative element (2), wherein The surface treatment step is selected from one or more of the following: varnish / primer, ink application, chemical etching of the surface, chemical functionalization, plasma etching, corona etching or vacuum physico-chemical surface treatment and / or deposition.

11. Method for producing a molded ophthalmic article (1) according to any one of the preceding claims, wherein The molded ophthalmic article (1) is subjected to a surface treatment step to reduce its thickness and optionally to acquire optical power.

12. Method for producing a molded ophthalmic article (1) according to any one of the preceding claims 1 to 10, wherein The molded ophthalmic article (1) is adapted to have a predefined thickness without requiring a surface treatment step.

13. Method for producing a molded ophthalmic article (1) according to any one of the preceding claims, wherein The at least one decorative element has an additional visual function selected from a photoluminescent effect, a phosphorescent effect or a photochromic effect or a combination thereof.

14. Method for producing a molded ophthalmic article (1) according to any one of the preceding claims, wherein The at least one decorative element has a maximum thickness that is approximately 80% of the thickness of the ophthalmic article lens (1) to which the at least one decorative element (2) is fixed.

15. Method for producing a molded ophthalmic article (1) according to any one of the preceding claims, wherein The first transparent plastic material, the second transparent plastic material and / or the supporting polymer thin wafer have additional functions and properties selected from the group consisting of a photochromic layer, a contrast enhancement filter, a vacuum coated surface, an anti-reflective coating and combinations thereof.

16. Method for producing a molded ophthalmic article (1) according to any one of the preceding claims, wherein In step b, the at least one decorative element (2) is fixed using an adhesive material, preferably comprising a cyanoacrylate or acrylic compound.

17. A method for producing a molded ophthalmic article (1) according to any one of the preceding claims, wherein The at least one decorative element (2) is transparent or exhibits a refractive index that is similar or the same as the refractive index of the transparent plastic material, wherein the at least one decorative element (2) does not have the ability to cause a localized change in the visible light transmittance of the molded ophthalmic article (1), wherein the at least one decorative element (2) is placed across the entire surface of the molded ophthalmic article (1).

18. Method for producing a molded ophthalmic article (1) according to any one of the preceding claims 1 to 13, wherein The at least one decorative element (2) is visible, or the at least one decorative element (2) is capable of causing a localized change in the visible light transmittance of the molded ophthalmic article (1), and the at least one decorative element (2) is positioned across the surface of the molded ophthalmic article (1) other than 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 the preceding claims.

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