Method for obtaining decorative articles having a sparkling appearance

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 glitter effect, preferably the appearance of a precious material, on at least one of its surfaces, and in particular, said article being an external watch component such as a dial. [Background technology]

[0002] A method for producing an article with a decorative surface structure by replicating a model with said decorative surface structure is known in the prior art. This method is based on a polymer molding, which can be used directly with a decorative PVD layer or can be used following replication by hot stamping of amorphous metals, as described in US Pat. No. 5,699,499, or replication by galvanic growth, as shown diagrammatically in FIG. 2 of the accompanying drawings. A model 1 having a structure 1a is provided (A). A polymer layer forming a negative replica 2 is molded onto the structure 1a of the model 1 (B). The model 1 is removed, and a conductive layer 3 is deposited in the cavity 2a of the negative replica 2 (C). A metal layer 4 is deposited on the surface of the replica 2 with the cavity 2a by galvanic growth (D). The replica 2 is removed, leaving an article 5, 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 an 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: 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, wherein one or more of the operations include: Local modification of the polycrystalline structure of the model; - Operations to modify the shape of the negative reproduction; 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 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 creating objects by imparting particular shapes to the negative reproduction or by selectively fabricating objects into 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 modifying the model, for example by engraving hidden data (logo, serial number, etc.).

[0009] Another aspect of the invention relates to the articles obtainable by the above method. [Brief explanation of the drawings]

[0010] [Figure 1] 1 shows a decorative article, in particular a dial, obtained using the method according to the invention. [Figure 2] 1 shows a schematic diagram of a method for obtaining an article by replication according to the prior art; [Figure 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] 10 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 INVENTION

[0011] The present invention relates to a method for obtaining decorative articles by replicating a model. This may be, for example, an external component of a piece of jewelry or a watch, such as a middle, case back, bezel, push-piece, bracelet link, flange, dial, hands, dial indices, etc. The article is characterized in that at least one of its faces has a sparkling, optionally precious, appearance. By way of example, an article 5 in the form of a dial bearing a logo 9 obtained using the method of the invention is shown in Figure 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 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, The decorative object 5 is either a negative reproduction 2 or a positive reproduction 4.

[0013] Model 1 with a polycrystalline structure is achieved by natural polycrystalline growth, also known as self-organization, which results in smooth facets and perfect edges on an atomic scale. For example, polycrystalline growth can be achieved by evaporation, by vacuum arc generation or microwave plasma, or by a high-temperature filament. In all cases, temperature is the governing factor for 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 replicated surface has a crystalline structure, which can also be described as a pattern that reproduces a crystalline structure not obtained by natural polycrystalline growth. In both cases, this relates to 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 material into a negative replica 2 used as a mold insert, or by stamping material onto the replica surface 2a. If the object 4 is obtained by galvanic growth, it is made from a metal or metal alloy. If the object is made from ceramic, it is made from a metal, polymer, or composite material, which may be amorphous, if it is obtained by injection molding or stamping. 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] To obtain specific optical effects, operations are performed on the model 1 during or after its manufacture. During the self-organizing growth process of the model 1, the growth parameters, in particular the temperature, are modified in a localized 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 polycrystalline appliqués, or to apply any other decoration.

[0018] Once the model 1 with the polycrystalline structure 1a has been produced, the shape of the crystal 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 a discrete logo, a data matrix, or a serial number, readable using special optical devices. The shape of the crystal 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 requires 2D, 2.5D and / or 3D shaping to improve aesthetic appearance and / or add functionality. Shaping consists of structuring the negative replica 2 before producing the object 4.

[0021] The LIGA (Lithography, Galvanoformation, Abformation) method is used for the 2D formation of an object 4 in a negative replica 2, as shown in Figure 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 portion of face 2a before 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 Figure 3, or by laser lithography in predetermined areas, which does not require a mask (E). Irradiated or unirradiated photoresist portions are removed by chemical means, depending on whether a positive or negative photoresist is used, to form a cavity 8 into which the object 4 is subsequently 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 layers, blind holes, etc.

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

[0024] For 3D molding, a negative replica 2 must be produced using a flexible polymer, such as silicone. This method is shown in FIG. 4 and consists of molding the flexible replica 2 into the desired shape and fixing it in this shape by placing it on a rigid substrate 11 (which in the illustrated example may be a second rigid polymer) of the desired shape (C). The replica 2 can, for example, be glued to the rigid substrate 11. Its shape can vary: dome-shaped, spherical, cylindrical, columnar, etc. Then, a conductive layer 3 required for galvanic growth is deposited (D). Alternatively, a metal layer 3 can be deposited before molding the polymer 2. Galvanic growth is then performed (E) to produce the object 4. Alternatively, the flexible polymer replica 2 molded in this manner can be used as an insert for an injection molding mold, and the object is obtained by injecting ceramic or metal, or any other injectable material, into the mold or by stamping. This allows for the creation of 3D articles with sparkling polycrystalline surfaces (F). For example, polycrystalline needles, polycrystalline middle sections, or links with polycrystalline structures can be produced.

[0025] The articles obtained by the various replication methods described above may then be finished by conventional machining, laser, water jet, coloring, or other shaping methods, for example by PVD, CVD, ALD, or galvanic deposition in the case of metal objects. Vacuum deposition of thin precious metal layers (gold, gold alloys, platinum, etc.) or precious metal appearances (yellow TiN, etc.) gives the article a precious appearance with a sparkling effect. For example, coloring with lacquer produces an article with a sparkling effect without the precious metal appearance.

[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 predetermined 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) with a sparkling appearance, comprising: providing or producing a model (1) based on polycrystalline growth, which model (1) has 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 model (1) from the negative replica (2); Including, After these steps, - an 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 give the decorative article (5) a particular optical effect and / or functional appearance, one or more of the operations comprising: - an operation of locally modifying the polycrystalline structure of said model (1); - modifying the shape of the negative copy (2); - selectively producing said object (4) on a predetermined portion of said replicated surface (2a) of said negative replica (2) when said optional step is performed; is selected from A method in which the decorative article (5) obtained is either the negative replica (2) or the positive replica (4) if the optional step is performed.

2. 2. The method of 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 the shape of a predetermined crystal.

4. 2. 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 the 2D shaping of the object (4) on the replicated surface (2a) of the negative replica (2), and the object (4) is - 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); - removing the irradiated or alternatively non-irradiated parts of said photoresist layer (6) so as to create cavities (8) exposing said conductive layer (3); galvanic growing of the object (4) in the cavity (8); The method according to claim 1, characterized in that the polymer is produced by the LIGA method having the steps of:

6. 6. The method according to claim 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 in view of a 2.5D shaping of the object (4) on 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 the object (4) a three-dimensional shape during the step of manufacturing the object (4), the step of manufacturing the negative replica (2) being carried out with a flexible polymer containing silicone, and then the negative replica (2) is molded to produce the three-dimensional shape and fixed to the three-dimensional shape.

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

9. 2. A method according to claim 1, characterized in that the object (4) is manufactured 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. A method according to claim 1, characterized in that it comprises as an additional step colouring the object (4) or the negative replica (2) if the object (4) or the negative replica (2) is intended to form the decorative article (5), said colouring being carried out by vacuum deposition onto the object (4) or onto the negative replica (2) or by galvanic growth on the object (4) if the object (4) is metallic.

12. 2. A method according to claim 1, 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, so that the facets of the replicated surface (2a) are covered only in predetermined directions to obtain a particular optical effect.

13. The method according to claim 1, characterized in that the decorative item (5) is a piece of jewelry or an external watch component.

14. 14. The method of claim 13, wherein the external watch component is a middle section, a dial, a hand, an appliqué, or a link.

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

16. 16. Method according to claim 15, characterized in that the one or more patterns and the relief are selected from a logo (9), a holographic image, a serial number, a data matrix and holes (10).

17. The method according to claim 13, characterized in that the decorative item (5) also has a precious appearance.

18. The method of claim 1, wherein the polycrystalline growth comprises a self-organized growth process.

19. The method described in claim 2, characterized in that the local change in temperature is used to engrave a logo or create a polycrystalline appliqué on the surface (1a) of the model (1).

Images