Black parts decorated with gemstones and method for preparing the same

Abstract

The invention relates to a component for internal assembly or mechanism of a watch or jewelry, comprising a substrate (2) partially coated with a black layer (3) and decorated with at least one gemstone (4), the black layer (3) comprising carbon nanotubes or aluminum oxide, the substrate (2) being free of the black layer (3) at least on the portion facing the gemstone (4). The invention also relates to a method for preparing the watch or jewelry component.

Description

Field of the Invention

[0001] The present invention relates to a component for a watch or jewellery interior fitting or mechanism. It also relates to a method for preparing said component. Background of the Invention

[0003] The black "color" can be obtained in the bulk of the material by its inherent color or by adding pigments or dyes to the material. The black "color" can also be present only on the surface. This surface coloration can be obtained in different ways, usually by oxidation / sulfidation / carbonization of the metal substrate or by depositing oxides / sulfides / carbides on the substrate. Carbon is therefore a well-known element for blackening surfaces. Deposited in an elongated manner in the form of nanotubes, the resulting material can be close to a perfectly absorbing black body, with a light absorption coefficient of up to 99.96% in the visible and near-infrared range. This black color is so perfect that the 3D shape of an object viewed from the front can be hidden.

[0004] The use of black coatings is known in the field of horology. From document EP3327517 a dial is known which has a first substrate coated with a black nanotube layer facing the watch glass and a second substrate fixed to the first substrate on the surface opposite to the glass. The first substrate is perforated to provide an opening which serves as a window intended to form an index. The second substrate comprises a luminescent coating at least in the area facing the opening so as to create a contrast between the black layer and the luminescent index at the first substrate.

[0005] The contrast is thus obtained by superimposing two substrates with different coatings. This superposition allows avoiding the selective deposition of two coatings on the same surface and eliminating the need to handle the particularly fragile nanotube layer. However, this superposition has the disadvantage of requiring the preparation of two substrates, which increases production costs.

[0006] From document CH711141 a method for preparing a dial is known in which a decoration, such as an indicia, is added to a carbon black coating. The decoration is prepared separately from the dial and then simply added to the dial, which allows to greatly facilitate the preparation of the dial. However, this preparation technique is not suitable for certain types of decoration, where the black color underneath the decoration affects the beauty and / or brilliance of the decoration.

[0007] In particular, this preparation technique is not well suited to decorative objects made of gemstones, especially diamonds. The difficulty lies in setting the gemstones on a dial coated with a black layer. The black layer must be discontinuous at the location of the gemstones (otherwise it would reduce their brightness) while perfectly surrounding them to obtain the desired contrast. Special attention must be paid to the preparation method in order not to damage the carbon nanotube layer. This layer can be so fragile that it is almost impossible to touch it without damaging the surface (revealing a shiny matte body or holes that contrast sharply with the original color of the carbon nanotubes).

[0008] Purpose of the Invention

[0009] The object of the present invention is to provide a method for producing a timepiece or jewelry part coated with black and decorated with gemstones and more particularly set with gemstones. This method is developed in such a way that the black coating is not damaged while obtaining a discontinuous black layer at the gemstone location.

[0010] Therefore, the preparation method according to the invention cannot be satisfied with adding a decoration, in this case a gemstone, to the coating as in the prior art. According to the invention, the decoration formed by the gemstone is prepared directly on the substrate and the black layer is selectively removed to maintain a surface without any black underneath the decoration.

[0011] More precisely, the invention relates to a method for preparing a part for an interior fitting or mechanism of a timepiece or jewellery, said part comprising a substrate at least partially coated with a black layer comprising carbon nanotubes or aluminium oxide, said coated substrate being decorated with at least one gemstone located in a cavity in the substrate, the substrate being free of the black layer at least on the surface of the cavity, said method comprising:

[0012] - step a) providing a substrate,

[0013] followed by, in unspecified order,

[0014] - step b) depositing a black layer on the substrate,

[0015] - step c) machining a recess in the substrate,

[0016] - step e) positioning and fixing the gemstone in the cavity,

[0017] The method comprises an additional step d) of selectively removing a black layer previously deposited on the substrate, such that at least the surfaces of the recesses are free of the black layer.

[0018] According to a variant of the method applicable when the black layer comprises carbon nanotubes, step b) is replaced by a step b′) of depositing a precursor layer comprising carbon nanotubes. The additional step d) is thus replaced by an additional step d′) of selectively removing the precursor layer so that at least the surface of the recess is free of the precursor layer. This method also comprises a step f) consisting in chemical or laser ablation of the precursor layer to reveal the black carbon nanotube layer.

[0019] The selective removal step d) or d') can be carried out mechanically, for example using a setting tool, or preferably by laser ablation. The selective removal can also be performed indirectly during the step of machining the recess or during the step of growing the support for the gemstone on the substrate by, for example, an additive manufacturing operation and more precisely by inkjet additive manufacturing.

[0020] The invention also relates to a part for an internal assembly or mechanism of a watch or jewellery, comprising a substrate partially coated with a black layer comprising carbon nanotubes or aluminium oxide and decorated with at least one gemstone set in a recess in or on the substrate, the substrate being free of the black layer at least on the part facing the gemstone or in other words on the surface of the recess.

[0021] For diamond decoration on carbon nanotube coating, the invention proposes to produce a watch or jewelry part with two allotropes of carbon on the surface mask, one very black for carbon nanotubes and the other very white for diamonds, allowing a very sharp brightness contrast.

[0022] Other features and advantages of the present invention will become apparent from the following description given with reference to the accompanying drawings.

[0023] BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A plan view of a timepiece provided with a dial coated according to the method of the invention and decorated with gemstones is shown. The enlarged view shows a gemstone with a setting element.

[0025] Figures 2 to 7 are schematic diagrams of different embodiments of the method according to the invention having steps performed in succession. Summary of the invention

[0026] The present invention relates to a component for an interior assembly or mechanism of a timepiece or jewellery. It can be selected from a non-exhaustive list comprising dials, hands, indexes, inlays, rotors, plates and ponts, etc. According to the invention, the component is at least partially coated with a black layer. The invention also relates to an assembly of two of said components at least partially coated with a black layer.

[0027] The following is Figure 1The invention is explained within the scope of the application of the watch dial 1 shown, which is formed by a substrate 2 coated with a black layer 3. The substrate can be made of a metallic material, such as steel, titanium, aluminum, an alloy of titanium or aluminum, brass or any other copper alloy. It can also be made of ceramic, cermet, sapphire, composite material or polymer material. The substrate 2 is decorated and preferably inlaid with one or more gemstones 4 distributed in the black layer 3. It can be a precious gemstone, such as diamond, a semi-precious stone or a synthetic gemstone, such as zirconium oxide, etc. According to the invention, the substrate is free of a black layer at least on the part facing the gemstone. The black layer can be present so as to be flush with the table of the gemstone. It is also conceivable to decorate the substrate with several rows of gemstones, wherein the substrate includes a black layer between the rows.

[0028] The substrate 2 includes Figure 2 The recess 5 shown serves as a seat for the gemstone 4, more specifically as a seat for the bottom 4a of the gemstone. The gemstone is preferably fixed in the seat by setting, using Figure 1 The setting element 6 is realized by means of a setting element 6 shown in the enlarged view of the dial. It can be a setting claw arranged in a cavity, a grain forming an integral part of the substrate, a groove in a cavity for a stick or invisible setting. According to the invention, the setting element is preferably also coated with a black layer to achieve a setting that does not appear to be visible to the user's eye. Visually, it blends into the black background of the dial. Alternatively, the invention does not exclude the use of an adhesive that does not reduce the brightness of the gemstone to glue it in the seat.

[0029] According to a variant of the invention, the black layer contains carbon nanotubes. The carbon nanotube layer contains at least 1% by weight, preferably at least 10% by weight of carbon nanotubes. The layer may be a varnish containing at least 1% by weight, preferably at least 10% by weight of carbon nanotubes. The higher the proportion, the darker the hue. The carbon nanotubes are randomly dispersed in this varnish. The varnish can be deposited, for example, by spraying. Alternatively, the layer contains at least 50% by weight, at least 60% by weight, at least 70% by weight, at least 80% by weight or at least 90% by weight of carbon nanotubes arranged vertically relative to the plane of the substrate, the remainder being composed of other forms of carbon. Preferably, the layer contains 100% by weight of carbon nanotubes arranged vertically relative to the plane of the substrate. The vertical arrangement of the nanotubes allows obtaining a darker black color relative to the random orientation of the carbon nanotubes in the varnish, but has the disadvantage that its mechanical strength is lower than that of the varnish. In order to overcome this disadvantage, a protective layer can be deposited on the black layer, but with the consequence of reducing the light absorption coefficient. The protective layer can be a thin layer of varnish or material such as Al2O3, TiO2 or SiO2, or a stacked layer of one or more of these materials deposited by ALD (atomic layer deposition). The nanotubes with vertical orientation are deposited by vacuum methods such as PVD (physical vapor deposition), CVD (chemical vapor deposition) or laser ablation synthesis. The carbon nanotube layer has a thickness of 1-100 μm.

[0030] According to another variant, the black layer is mainly composed of aluminum oxide Al x O y Such as Al2O3 and supplemented with non-ferrous metal oxides, such as, for example, copper, zinc or manganese oxides. The layer contains at least 90% Al x O y , preferably 100% Al x O y The aluminum content of the aluminum oxide is between 45% and 65% by weight, preferably between 45% and 50% by weight. The thickness of the layer is between 1 and 50 microns, preferably between 2 and 10 microns, more preferably between 4 and 7 microns. It can be deposited by PVD, CVD or PECVD (plasma enhanced chemical vapor deposition).

[0031] The component according to the invention can be Figures 2 to 7 For simplicity, Figures 2 to 7 Only the substrate provided with the recess for the gemstone is illustrated, without showing the setting element. Any step involving the machining of the recess necessarily includes mechanical preparation of the setting element (eg a die).

[0032] The method for producing the component comprises, in no particular order, steps b) to e):

[0033] - step a) providing a substrate 2,

[0034] - step b) depositing a black layer 3 on the substrate 2, or step b') depositing a precursor layer 7 comprising carbon nanotubes for the variant with carbon nanotubes,

[0035] - step c) machining a recess 5 in or on the substrate 2,

[0036] - step d) selectively removing the black layer 3 or step d′) selectively removing the precursor layer 7 previously deposited on the substrate 2, so that at least the surface of the recess 5 is free of the black layer 3 or the precursor layer 7,

[0037] - Step e) Positioning and fixing the gemstone 4 , preferably setting it in the cavity 5 .

[0038] according to Figures 2 to 5 In the first embodiment shown, the method for preparing the component comprises:

[0039] - Step a) providing a substrate 2 ( Figure 2-5 ),

[0040] - Step b) Deposition of a black layer 3 on all or part of the substrate 2, including the areas intended to form the recesses ( Figure 2 )、Cavity 5( Figure 3) or the upper surface of the gem 4, i.e. the table and crown of the cut gem ( Figure 4-5 ),

[0041] - Step d) from the area where the recess 5 is to be formed ( Figure 2 )、Cavity 5( Figure 3 ) or the upper surface of gem 4 ( Figure 4-5 )Selectively remove the black layer 3.

[0042] It also comprises the step c) machining a recess 5 in the substrate 2 and the step e) positioning and fixing the gemstone 4 on the substrate 2. Fixing includes setting as well as other fixing techniques such as gluing.

[0043] for Figure 2 In the variant shown, the black layer 3 is deposited on the substrate 2 before machining the recess 5. The black layer 3 is then removed during the machining of the recess 5, i.e. steps c) and d) are one and the same step. Finally, step e) is performed.

[0044] for Figure 3 In the variant shown, the black layer 3 is deposited on the substrate 2 after the recess 5 is processed in step c). The black layer 3 is then removed at the location of the recess 5. The removal can be carried out mechanically, in particular manually using a splicing tool. According to a preferred variant, this selective removal is carried out by laser ablation, more preferably using a pulsed laser, such as a nanosecond, picosecond or femtosecond laser. Finally, step e) is carried out.

[0045] for Figure 4 In the variant shown, the black layer 3 is deposited on a substrate 2 already decorated with gemstones 4. The black layer 3 on the gemstones 4 is then removed mechanically or preferably by laser ablation using a pulsed laser as before. Figure 4 This variant is preferred because after selectively removing the black layer, no surface treatment is required, which is different from Figure 3 In contrast to the variant in Figure 3 In the present invention, it is still necessary to mount the substrate after the selective removal step.

[0046] for Figure 5In the variant shown, the substrate 2 is decorated with gemstones 4 according to step e). The method then comprises an additional step f) of applying a mask 8 to the gemstones 4. The mask can be a lacquer, an adhesive or a photosensitive film, among others. It can be deposited, for example, by photolithography, stereolithography, digital printing or manually (for adhesives or films). Then in step b), a black layer 3 is deposited on the substrate 2, including on the mask 8. Finally, in step d), the black layer 3 is selectively removed using the mask 8. The mask can be removed by laser ablation or mechanically, for example manually using a special tool. In an alternative manner (not shown), the mask can be positioned on the recess before positioning the gemstone. In this case, the black layer is deposited and selectively removed before positioning the gemstone.

[0047] according to Figure 6 In the second embodiment shown, step b) is replaced by step b'), which deposits a precursor layer 7 on the substrate 2 (including on the surface of the recess 5). Step b') includes depositing the precursor layer and annealing it to polymerize the precursor. This variation is suitable for black layers based on carbon nanotubes. The precursor comprises a polymer and carbon nanotubes. The weight percentage of the carbon nanotubes is between 0.1-15 weight %, and the weight percentage of the polymer is between 85-99.9 weight %. The polymer can be selected from thermoplastics such as polyamides, polybutylenes, polyethylene, polyimides, polypropylene, polystyrene, polyvinyl acetate and polymethyl methacrylate or from thermosetting plastics such as polyepoxides and polyurethanes. In order to improve the adhesion between the polymer and the carbon nanotubes, the latter can be pre-functionalized. For example, for a polyimide matrix, the carbon nanotubes can be pre-functionalized by ablation in an acidic medium such as nitric acid. The precursor comprising a mixture of carbon nanotubes distributed in a polyimide matrix is ​​deposited and polymerized at a temperature of 150-350° C. for 1 to 7 hours.

[0048] Then comes step d) selective removal of the precursor layer 7 deposited in the recesses 5. Preferably, this selective removal is performed by laser ablation, but it can also be achieved manually using a suitable tool. This is followed by step e) positioning and fixing the gemstone 4 in the recess 5 of the substrate 2. Finally, in step f), the precursor layer 7 is subjected to chemical or laser ablation, which exposes the carbon nanotubes in the precursor layer to form the black layer 3. Chemical ablation can be carried out in an acidic medium (for example formic acid, acetic acid, sulfuric acid, nitric acid, hydrochloric acid or hydrofluoric acid) or in a suitable solvent (such as m-cresol), depending on the type of polymer matrix. The purpose of this ablation step is to partially dissolve the polymer matrix of the precursor layer, produce surface roughness, and thus expose a microstructure rich in carbon nanotubes and suitable for capturing light. Laser ablation using a pulsed laser (for example a femtosecond or picosecond laser) can also be considered to create such a surface microstructure.

[0049] In an alternative manner (not shown), step b') can be carried out before step c) of processing the recess, steps c) and d') then being one and the same concomitant step of processing the recess and selectively removing the precursor layer from the recess location. In another alternative manner (not shown), the precursor layer can be deposited on a substrate set with gemstones, and the precursor on the gemstones is then selectively removed.

[0050] according to Figure 7 In the third embodiment shown, the method comprises an additional step h) of growing material on the substrate 2 coated with the black layer to form a support 11 for receiving the gemstone 4. It thus comprises in sequence:

[0051] - step a) providing a substrate 2,

[0052] - step b) depositing a black layer 3 on the substrate 2,

[0053] - step h) growing material on the coated substrate 2 to form the support 11, this step being accompanied by step d) selectively removing the black layer 3,

[0054] - Step e) Positioning and fixing of gemstones 4 in recesses 5 provided on substrate 2 in support 11 .

[0055] The material growth step is carried out by additive manufacturing, such as digital printing, electroforming, laser sintering or any other derivative additive method. The material can be a metallic material, a ceramic material or a polymer material. In this step, the black layer 3 will be automatically and selectively removed from the support 11, which allows the substrate 2 to be released facing the gemstone 4 to be set.

[0056] The recesses 5 can be produced directly during the growth step h) or can be processed later before step e).

[0057] All embodiments are shown for inlay elements which are covered with a black layer to blend in with the background of the dial. However, the invention does not exclude the selective removal of the black layer from the recesses also involving inlay elements.

[0058] Finally, the invention also relates to an assembly comprising a first component and a second component, each component being used for internal assembly or mechanism of a watch or jewelry. According to the invention, the first and second components comprise at least one portion coated with a black layer. Preferably, the first component can have a relative movement relative to the second component and is mounted facing the second component. The first component is decorated with one or more gemstones. For example, the first component is a pointer coated with a black layer and decorated with gemstones set or adhered to the tip of the pointer, and the second component is a dial coated with a black layer.

[0059] Legend

[0060] (1) Dial

[0061] (2) Base material

[0062] (3) Black layer

[0063] (4) Gemstones

[0064] a. The bottom of the gemstone

[0065] (5) Concave

[0066] (6) Inlay components

[0067] (7) Precursor layer

[0068] (8) Mask

[0069] (11) Support

Claims

1. A method for preparing a component for internal assembly of a watch or jewelry, the component comprising a substrate (2) at least partially coated with a black layer (3) and decorated with at least one gemstone (4), the gemstone being set in a recess (5) located in the substrate (2), the black layer (3) comprising carbon nanotubes or aluminum oxide, and the substrate (2) having no black layer (3) at least on the surface of the recess (5), the black layer (3) being flush with the table of the gemstone (4), the method comprising in sequence: - Step a) providing a substrate (2), - step c) machining a recess (5) in the substrate (2), - step e) positioning and fixing the gemstone (4) in the recess (5) of the substrate (2), - step b) depositing a black layer (3) on the substrate (2), including on the free surface of the gemstone (4), - step d) selectively removing the black layer (3) deposited on the free surface of the gemstone (4); Or the method comprises in sequence: - Step a) providing a substrate (2), - step c) machining a recess (5) in the substrate (2), - step e) positioning and fixing the gemstone (4) in the recess (5) of the substrate (2), - step f) positioning the mask (8) on the free surface of the gemstone (4), - step b) depositing a black layer (3) on the substrate (2), including on the mask (8), - step d) selectively removing the black layer (3) by removing the mask (8); Or the method comprises in sequence: - Step a) providing a substrate (2), - step c) machining a recess (5) in the substrate (2), - step f) positioning the mask (8) on the surface of the cavity (5), - step b) depositing a black layer (3) on the substrate (2), including on the mask (8), - step d) selectively removing the black layer (3) by removing the mask (8), - Step e) Positioning and fixing the gemstone (4) in the recess (5) of the substrate (2).

2. A method for producing a component for internal assembly of a watch or jewellery, the component comprising a substrate (2) at least partially coated with a black layer (3) and decorated with at least one gemstone (4) set in a recess (5) in the substrate (2), the black layer (3) comprising carbon nanotubes, and the substrate (2) being free of the black layer (3) at least on the surface of the recess (5), the black layer (3) being flush with the table of the gemstone (4), the method comprising: - Step a) providing a substrate (2), The following steps follow, in no specified order: - step b') depositing a precursor layer (7) comprising carbon nanotubes on the substrate (2) and annealing it, - step c) machining a recess (5) in the substrate (2), - step e) positioning and fixing the gemstone (4) in the recess (5) of the substrate (2), The method comprises the additional steps d') of selectively removing the precursor layer (7) so that at least the surface of the recesses is free of the precursor layer (7) and f) of chemically or laser ablating the precursor layer (7) to form a black layer (3) on the substrate (2).

3. The preparation method according to claim 2, characterized in that: These include, in order: - Step a) providing a substrate (2), - step c) machining a recess (5) in the substrate (2), - step b') on the substrate (2), comprising depositing a precursor layer (7) comprising carbon nanotubes on the surface of the recesses (5) and annealing it, - step d') of selectively removing the precursor layer (7) deposited on the surface of the recesses (5), - step e) positioning and fixing the gemstone (4) in the recess (5) of the substrate (2), - Step f) chemically or laser ablating the precursor layer (7) to form a black layer (3) on the substrate (2).

4. The preparation method according to claim 2, characterized in that: These include, in order: - Step a) providing a substrate (2), - step b') depositing a precursor layer (7) on the substrate (2) and annealing it, - step c) machining a recess (5) in the substrate (2), causing the precursor layer (7) to be selectively removed at the location of the recess (5), - step e) positioning and fixing the gemstone (4) in the recess (5) of the substrate (2), - Step f) chemically or laser ablating the precursor layer (7) to form a black layer (3) on the substrate (2).

5. The preparation method according to claim 2, characterized in that: These include, in order: - Step a) providing a substrate (2), - step c) machining a recess (5) in the substrate (2), - step e) positioning and fixing the gemstone (4) in the recess (5) of the substrate (2), - step b') on the substrate (2), comprising depositing a precursor layer (7) on the free surface of the gemstone (4) and annealing it, - step d') of selectively removing the precursor layer (7) deposited on the free surface of the gemstone (4), - Step f) chemically or laser ablating the precursor layer (7) to form a black layer (3) on the substrate (2).

6. The preparation method according to any one of claims 2 to 5, characterized in that The precursor layer includes a polymer and carbon nanotubes.

7. The preparation method according to claim 6, characterized in that: The weight percentage of the carbon nanotubes is 0.1 to 15 weight %, and the weight percentage of the polymer is 85 to 99.9 weight %.

8. The preparation method according to claim 6, characterized in that: The polymer is selected from the group consisting of polyamide, polybutylene, polyethylene, polyimide, polypropylene, polystyrene, polyvinyl acetate, polymethyl methacrylate, polyepoxide and polyurethane.

9. The preparation method according to any one of claims 2 to 5, characterized in that The precursor layer (7) has a thickness of 10-200 microns.

10. The preparation method according to any one of claims 2 to 5, characterized in that The precursor layer (7) has a thickness of 100-200 microns.

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