Decorative article with sparkling appearance, and method for obtaining the same

Abstract

To provide a method for obtaining a decorative article with a sparkling appearance, and to provide the decorative article.SOLUTION: A method for obtaining a decorative article with a sparkling appearance includes the steps of: providing a model 1 having a face 1a of a polycrystalline structure which is intended to be replicated; and manufacturing a replica 2 of the face 1a by using a polymer material; and subsequent to the above steps, optionally manufacturing an object 4 at least on a part of a replicated face 2a of the replica 2. In order to impart specific optical effects and / or a functional appearance to a decorative article, The method further implements one or more operations during the steps. Therein: one or more operations out of those operations are selected from among an operation for locally modifying a polycrystalline structure of the model 1, an operation for modifying a shape of the replica 2, and an operation for selectively manufacturing the object 4 at a predetermined section of the replicated face 2a of the negative replica 2, before manufacturing the replica 2; and the decorative article is either the replica 2, or the object 4 of when the optional step is implemented.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing an article having a glittering effect, preferably the appearance of a precious material, on at least one of its surfaces, in particular said article being an external watch component such as a dial. [Background technology]

[0002] A method is known in the prior art for manufacturing an article with a decorative surface structure by using a method for replicating a model with said decorative surface structure. This method is based on a polymer molding, which is either used as is with a decorative PVD layer or following a replication by hot stamping of amorphous metal as described in US Pat. No. 5,399,363 or a replication by galvanic growth as shown diagrammatically in FIG. 2 of the drawings attached hereto. A model 1 is provided with a structure 1a (A). A polymer layer forming a negative replica 2 is molded on the structure 1a of the model 1 (B). The model 1 is removed and a conductive layer 3 is deposited in the cavities 2a of the negative replica 2 (C). A metal layer 4 is deposited by galvanic growth on the face of the replica 2 with the cavities 2a (D). The replica 2 is removed, leaving an article 5 which is a copy of the original model 1 (E). Optionally, this article 5 can be reused as a model for making additional parts. The polymer negative replica 2 may be the final article. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] U.S. Patent No. 5,950,704 Summary of the Invention

[0004] The present invention aims to improve this replication method to produce articles with a shimmering polycrystalline surface, optionally with the appearance of a precious material. In particular, the method is adapted to give the surface of the article a specific shape and / or specific optical effects for decorative and / or functional purposes.

[0005] In particular, the present invention relates to a method for obtaining a decorative article having a sparkling appearance, said method comprising the steps of: providing or producing a model having a face of the polycrystalline structure intended to be replicated; - producing a negative replica of said surface using a polymeric material; Separating the model from its replicas; Including, After these steps, followed by the optional step of producing an object, also called a positive replica, on at least a portion of the replicated surface of the negative replica, The method is characterized in that one or more operations are implemented between the aforementioned steps to impart a particular optical effect and / or functional appearance to the decorative article, the one or more operations being: Local modification operations for the polycrystalline structure of the model; - Modifying the shape of the negative copy; - selectively producing an object on a predetermined portion of the replicated surface of the negative replica; is selected from The decorative article is either a negative reproduction or an object when optional steps are performed.

[0006] The shiny, optionally precious appearance of the article is imparted by the polycrystalline nature of the model, and by patterning the crystals during or after the manufacture of the model, there are special decorative effects associated with the controlled variations in crystal growth. The more or less precious appearance of the article depends on the choice of materials for the positive replica and the finishing treatments applied to the article after replication.

[0007] Other decorative effects can be obtained when making objects by imparting particular shapes to the negative reproduction or by selectively fabricating objects in the negative reproduction.

[0008] Functional aspects can also be added by this particular shape of the replica, by selective manufacturing of the object or by modification of the model, for example by inscribing hidden data (logos, serial numbers, etc.).

[0009] Another aspect of the invention relates to an article obtainable by said method. [Brief description of the drawings]

[0010] [Figure 1] 1 shows a decorative article, specifically a dial, obtained using the method according to the invention. [Diagram 2] 1 shows a schematic diagram of a method for obtaining an article by replication according to the prior art; [Diagram 3] 1 shows a schematic representation of a manufacturing method according to an alternative embodiment of the invention involving 2D molding of an object onto a polymer negative replica. [Figure 4] 1 shows a schematic representation of a manufacturing method according to another alternative embodiment of the invention involving 3D molding of a polymer negative replica. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The present invention relates to a method for obtaining a decorative article by replicating a model. This may be, for example, an external component of a piece of jewellery or a watch, such as a middle part, a back cover, a bezel, a push piece, a bracelet link, a flange, a dial, hands, dial indexes. The feature of this article is that at least one of its faces has a sparkling, optionally precious, appearance. As an example, an article 5 in the form of a dial bearing a logo 9 obtained using the method of the invention is shown in FIG. 1.

[0012] The method for obtaining the decorative article 5 comprises, as a prelude, the following steps known in the art: providing or manufacturing a model 1 having a face 1a of a polycrystalline structure which is intended to be replicated; - producing a negative replica 2 of said surface 1a using a polymer material; - separating the negative replica 2 from the model 1; Optionally, producing an object 4, also called a positive replica, on at least a portion of the replicated surface 2a of the negative replica 2. Including, Said decorative object 5 is either a negative reproduction 2 or a positive reproduction 4.

[0013] Model 1 with polycrystalline structure is obtained by natural polycrystalline growth, also called self-organization, which results in smooth facets and perfect edges on the atomic scale. For example, polycrystalline growth can be achieved by evaporation, by vacuum arc generation or microwave plasma, or by high temperature filaments. In all cases, temperature is the factor that governs the crystal growth in the model.

[0014] The polycrystalline material of the model 1 may be, for example, a metal, diamond or ceramic material. Alternatively, the model may be a part manufactured from a pre-made replica. In this case, the surface to be replicated has a crystalline structure, which can also be described as a pattern reproducing a crystalline structure not obtained by natural polycrystalline growth. In both cases, this concerns a model 1 with a surface 1a having a polycrystalline structure.

[0015] The object 4 is obtained by electroforming a metal onto the replica surface 2a previously coated with a conductive layer 3, by injecting a material into the negative replica 2 used as a mold insert, or by stamping a material onto the replica surface 2a. If the object 4 is obtained by galvanic growth, it is made from a metal or a metal alloy. If the object is made from a ceramic, if it is obtained by injection molding or stamping, it is made from a metal, a polymer or a composite material, which may be amorphous. If the article 5 is a negative replica 2, it is made from a polymer.

[0016] According to the invention, decorative and / or functional effects in the article are obtained by one or more of the following operations performed on the model 1, on the negative replica 2, or on both during the manufacturing process:

[0017] Operations are performed on the model 1 during or after its manufacture in order to obtain certain optical effects. During the self-organizing growth process of the model 1, the growth parameters, in particular the temperature, are modified in a local and controlled manner to selectively change the size and / or orientation of the crystals on the surface of the model 1. This results in additional optical effects in terms of sparkle, for aesthetic purposes. For functional and / or decorative purposes, the local variation of the growth parameters can be used to inscribe a logo on the polycrystalline surface 1a of the model 1, to create a polycrystalline appliqué or any other decoration.

[0018] Once the model 1 with the polycrystalline structure 1a has been produced, the shape of the crystals can be modified by reworking and chamfering its vertices and faces. This can be accomplished, for example, by selective laser etching or local machining. This also results in additional optical effects in terms of sparkle, for aesthetic purposes. This makes it possible, for example, to create holographic images. For functional purposes, it can be used to inscribe hidden data, such as discrete logos, data matrices or serial numbers, readable using special optical devices. The shape of the crystals can be modified either on the original model 1 or on the positive copy 4 that serves as the model.

[0019] According to the invention, operations during and after the manufacture of the model 1 can be combined.

[0020] Operations can also be carried out on the polymer negative replica 2. This entails 2D, 2.5D and / or 3D shaping with the aim of improving the aesthetic appearance and / or adding functionality. Shaping consists of structuring the negative replica 2 before producing the object 4.

[0021] The LIGA (Lithograpie, Galvanoformung, Abformung) method is used for the 2D shaping of the object 4 in the negative replica 2, as shown in FIG. 3. After depositing a conductive layer 3 on the face 2a of the replica 2, for example by PVD vacuum deposition (C), a photoresist layer 6 is deposited on at least a part of the face 2a before the galvanic growth of the object 4 (D). This photoresist layer 6 is selectively irradiated through a pre-structured mask 7, i.e. by conventional photolithography as shown in FIG. 3, or by laser lithography in predetermined parts without the need for a mask (E). The irradiated or non-irradiated photoresist parts are removed by chemical means, depending on whether the photoresist used is positive or negative, respectively, forming a cavity 8 in which the object 4 is then produced by electroforming (F). This allows for the creation of articles with intricate contours, through holes 10, sharp edges, etc., while retaining a brilliant polycrystalline surface.

[0022] For 2.5D molding, the method is essentially the same, with the steps of depositing a conductive layer and irradiating a photoresist layer being repeated multiple times to form tiers or blind holes, etc.

[0023] For 2D and 2.5D molding, traditional machining can also be used to add complex structures.

[0024] For 3D moulding, it is necessary to produce a negative replica 2 using a flexible polymer, for example silicone. This method is shown in FIG. 4 and consists of moulding the flexible replica 2 to the desired shape and fixing it in this shape by placing it on a rigid substrate 11 of the desired shape, which in the example shown may be a second rigid polymer (C). The replica 2 may for example be glued to the rigid substrate 11. It may have different shapes: it may be dome-shaped, spherical, cylindrical or columnar, etc. Then the conductive layer 3 required for galvanic growth is deposited (D). Alternatively, the polymer 2 may be moulded after the metal layer 3 has been deposited. Then the galvanic growth is carried out (E) and the object 4 is produced. Alternatively, the flexible polymer replica 2 moulded in this way may be used as an insert in an injection mould, and the object is obtained by injecting ceramic or metal or any other injectable material into the mould, or by stamping. This allows the production of 3D articles with sparkling polycrystalline surfaces (F). For example, links with polycrystalline needles, polycrystalline middle sections, or polycrystalline structures can be produced.

[0025] The articles obtained by the various replication methods mentioned above may then be finished by shaping methods such as conventional machining methods, laser methods, water jet methods, coloring methods, for example by PVD, CVD, ALD, or galvanic growth in the case of metal objects. By vacuum deposition of a thin precious metal layer (gold, gold alloys, platinum, etc.) or a precious metal appearance (yellow TiN, etc.), the article acquires a precious appearance with a sparkling effect. For example, coloring with lacquer produces an article without the precious metal appearance but with a sparkling effect.

[0026] In one alternative embodiment of the invention, the coloring by vacuum deposition is performed conformally on the facets of the polycrystalline structure. In the case of directional PVD, this requires normal incidence on the surface of the negative replica or object or rotation of the part to obtain a homogeneous coloring.

[0027] In another alternative embodiment of the invention, the directionality of the PVD process, and in particular the directionality of the deposition, is used to color the polycrystalline surface of a negative replica or object by deposition of a metallization or dielectric layer with oblique or grazing incidence, so that facets are covered only in certain orientations to give a particular optical appearance. [Explanation of symbols]

[0028] 1. Model 1a. Polycrystalline surface 2. Negative Reproduction 2a. Replication side 3.Conductive layer 4. Objects (also called positive reproductions) 5. Decorative items 6. Photoresist Layer 7. Mask 8. Cavity 9. Logo 10. Hole 11. Rigid substrate

Claims

1. A method for obtaining a decorative article (5) having a glittering appearance, comprising the steps of: - providing or producing a model (1) having a surface (1a) of a polycrystalline structure intended to be replicated; - producing a negative replica (2) of said surface (1a) using a polymeric material; - separating the negative replica (1) from the model (2); Including, After these steps, - the optional step of producing an object (4), also called a positive replica, on at least a portion of the replicated surface (2a) of said negative replica (2), The method is characterized in that one or more operations are implemented between the aforementioned steps in order to impart a particular optical effect and / or functional appearance to the decorative article (5), one or more of the operations comprising: - locally modifying the polycrystalline structure of the model (1); - modifying the shape of the negative replica (2); - selectively producing said object (4) on a predetermined portion of said replicated surface (2a) of said negative replica (2) if said optional step is performed; is selected from A method according to claim 1, wherein the decorative article (5) obtained is either the negative replica (2) or, if the optional step is performed, the positive replica (4).

2. 2. The method according to claim 1, characterized in that the polycrystalline structure of the model (1) is modified during the production of the model (1) by locally varying the temperature of the model (1) during crystal growth.

3. 2. A method according to claim 1, characterized in that the structure of the surface (1a) of the model (1) is modified after the production of the model (1) by reworking a predetermined crystal shape.

4. 4. The method according to claim 1, characterized in that the shape of some vertices and faces of the crystals of the surface (1a) of the model (1) is modified by selective laser etching or by local machining.

5. The object (4) is selectively manufactured at a predetermined position on the replicated surface (2a) of the negative replica (2) in view of a 2D shaping of the object (4) on the replicated surface (2a) of the negative replica (2), the object (4) being - depositing a conductive layer (3) on the replicated surface (2a) of the negative replica (2); - depositing a photoresist layer (6) on said conductive layer (3); - selectively irradiating said photoresist layer (6); the sub-step of removing the irradiated or alternatively non-irradiated parts of said photoresist layer (6) so as to create cavities (8) exposing said conductive layer (3); - galvanically growing said object (4) in said cavity (8); The method according to claim 1 , characterized in that the LIGA method is used.

6. 6. The method according to any one of claims 1 to 5, characterized in that the steps of depositing the conductive layer (3), depositing the photoresist layer (6), selectively irradiating the photoresist layer (6), removing parts of the photoresist layer (6) and galvanically growing the object (4) are repeated several times, taking into account a 2.5D shaping of the object (4) at the replicated surface (2a) of the negative replica (2).

7. 2. The method according to claim 1, characterized in that the negative replica (2) is molded to give a three-dimensional shape to the object (4) during the step of producing the object (4), the step of producing the negative replica (2) being carried out with a flexible polymer such as silicone, after which the negative replica (2) is molded to produce the desired shape and fixed in this shape.

8. 8. A method according to claim 7, characterized in that the negative replica (2) is fixed in said shape by being fixed to a rigid substrate (11).

9. 2. The manufacturing method according to claim 1, characterized in that the object (4) is produced by electroforming, by injection or by stamping.

10. 2. The method according to claim 1, characterized in that the object (4) is made from a material selected from metals, metal alloys, ceramics, polymers and composite materials.

11. 2. The method according to claim 1, characterized in that it comprises as an additional step coloring the object (4) or the negative replica (2) if the negative replica (2) is intended to form the article (5), said coloring being performed by vacuum deposition on the object (4) or on the negative replica (2) or by galvanic growth on the object (4) if the latter is metallic.

12. 12. A method according to any one of the preceding claims, characterized in that the object (4) is coloured by deposition of a metal or dielectric material applied by directional PVD with oblique or grazing incidence, in such a way that the facets of the replicated polycrystalline surface are covered only in certain directions to obtain a particular optical effect.

13. A decorative article (5) having a sparkling appearance obtained using the method of claim 1, characterized in that said decorative article (5) is a piece of jewellery or an external watch component.

14. 14. Decorative article (5) according to claim 13, characterized in that said external clock component is a middle section, a dial, a hand, an applique or a link.

15. Decorative article (5) according to claim 13, characterized in that it comprises one or more patterns, reliefs and / or non-flat shapes.

16. Decorative article (5) according to claim 15, characterized in that said one or more patterns and said reliefs are selected from a logo (9), a holographic image, a serial number, a data matrix and holes (10).

17. Decorative article (5) according to claim 13, characterized in that it also has a precious appearance.

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