Black component and method for producing the same

Abstract

The invention relates to a component for the internal assembly or mechanism of a timepiece or piece of jewelry, comprising a substrate (2) at least partially coated with a black layer (3) comprising aluminum oxide. It also relates to a method for producing this component.

Description

TECHNICAL FIELD

[0001] The present invention relates to a component at least partially covered in black. This component is used for the interior fitting or the movement of a watch or a piece of jewelry. It also relates to a method for preparing said component. BACKGROUND

[0003] The black "color" can be obtained in the bulk of the material either by the intrinsic color of the material or by the addition of pigments or dyes in the material. The black "color" can also exist only on the surface. This surface coloring can be obtained in different ways, generally by oxidation / sulfuration / carbonization of the metal substrate or by deposition of oxides / sulfides / carbonates on the substrate. Carbon is thus a well-known element for blackening the surface. Deposited in nanotube form in an elongated way, the material formed can approach a perfect black body with a light absorption coefficient up to 99.96% in the visible and near infrared range. This black is so perfect that it makes it possible to hide the 3D shape of the object seen from the front.

[0004] The use of black coatings is known in the watchmaking field. From document EP 3327517, a dial is known having a first substrate coated with a layer of black nanotubes facing the watch glass and a second substrate fixed to the first substrate on the surface opposite 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 superimposition allows to avoid selectively depositing two coatings on the same surface and no longer requires handling a nanotube layer which is particularly fragile. However, this superimposition has the drawback of requiring the preparation of two substrates which increases the production costs.

[0006] From document CH 711141, a method for preparing a dial is known in which a decoration, i.e. an index, is added on a carbon black coating. This decoration is prepared separately from the dial and is then simply added to the dial, which allows to greatly facilitate the preparation of the dial.

[0007] Currently, these ultra-black absorber deposits are formed from forests of vertically grown carbon nanotubes using chemical vapor deposition methods. To maximize the deep black appearance of the coating on the substrate, most of the carbon nanotubes must be deposited in a controlled direction perpendicular to the substrate. This method applied directly to the watch is complex to implement. In another method, carbon nanotube-based paints or varnishes can be applied by spraying. The second method is easier to implement, but produces a lower intensity of black. In both cases, the application and use of carbon nanotubes are complex to implement and can present potential hazards in terms of safety during the preparation of the coating, the assembly of the watch and the SAV operation. Furthermore, the forest structure of the carbon nanotube-based coating makes it very fragile and difficult to handle. These coatings have very low mechanical strength and can easily be crushed even under slight mechanical pressure. The layer can be so fragile that it is almost impossible to touch it without damaging the surface, showing a shiny mist of threads or holes in sharp contrast with the original color of the carbon nanotubes. In addition, the forest structure of the coating does not allow the use of conventional direct printing techniques to apply superimposed decorations on the surface.

[0008] Object of the invention

[0009] The object of the present invention is to overcome the disadvantages of carbon nanotube-based coatings by providing another ultra-absorbing, more solid and more compact black coating to allow conventional handling and decoration operations in the field of watches or jewelry.

[0010] According to the invention, the black coating comprises a metal oxide, in particular aluminum oxide deposited by a PVD, CVD or PECVD type method. This ultra-black decorative coating has the following characteristics:

[0011] - a reflectance of less than 1.5% and a lightness value L in the CIELAB system of less than 12, preferably 7, which allows to achieve a high lightness contrast and a high color contrast with respect to the decoration;

[0012] - a compact structure allowing the application of decorations on the surface of the coating;

[0013] - allowing to enhance the microns thickness of parts with complex surface geometry and / or characteristic watch decorations;

[0014] - allowing the mechanical strength of the coated parts to be assembled in a watch or to be handled for decoration operations.

[0015] The invention relates to parts at least partially coated with such a black coating and to a method for preparing said parts.

[0016] Other features and advantages of the invention will become apparent in the following description, made with reference to the attached drawings.

[0017] Brief description of the drawings

[0018] Figure 1 is a plan view of a watch equipped with a dial coated and decorated according to the method of the application.

[0019] Figures 2A to 6 is a schematic view of different embodiments of the method according to the application with successive implementation steps. SUMMARY

[0020] The present application relates to a component for the internal assembly or mechanism of a watch or a jewel. It can be chosen from the non-exhaustive list comprising a dial, a flange, a hand, an index, a setting, a balance, a bridge and a pont. According to the present application, the component is at least partially coated with a black layer. As described hereafter, the present application also relates to an assembly of two said components at least partially coated with a black coating.

[0021] In the following, the present application will be described in the scope of a watch dial 1 formed of a substrate 2 at least partially coated with a black coating 3, as schematically shown in Figure 1 . Said substrate can be made of a metallic material such as steel, titanium, aluminum, titanium or aluminum alloys, brass or any other copper containing alloy. It can also be made of a ceramic material, a cermet, sapphire, glass, silicon, a composite material or a polymer.

[0022] According to the present application, the black layer, also called black coating, is a layer mainly comprising aluminum oxide AI x O y such as for example copper, zinc, nickel, chromium, silver or manganese. The layer comprises at least 90% AI x O y , preferably 100% AI 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 (Physical Vapor Deposition), CVD (Chemical Vapor Deposition) or PECVD (Plasma-Enhanced Chemical Vapor Deposition).

[0023] The superabsorbent black deposit according to the present application has a reflectance value in the visible range of less than 2% and more particularly less than 1.5%, as reproduced in Table 1 for a coating thickness between 4 and 7 microns. The measured values are total hemispherical reflectance (THR) measurements obtained by optical absorption spectroscopy.

[0024] Coating Average reflectivity Minimum reflectivity Maximum reflectivity 1 1.1％ 1.05％ 1.22％ 2 1.19％ 1.14％ 1.26％

[0025] Table 1

[0026] The brightness of the watch thus coated has the following characteristics in the CIELAB color system (according to standard CIE No. 15, ISO 7724 / 1, DIN 5033 Teil 7, ASTM E-1164):

[0027] - an L* value less than 12, preferably less than 7;

[0028] - an a* value between -2 and +2, preferably between -1 and +1 ;

[0029] - a b* value between -3.5 and +5, preferably between -3.5 and +1.

[0030] The black coating has a dense microstructure. This dense structure allows the application of a decoration without damaging the black coating. The decoration can be of any kind. It can be a time indicator (optionally luminescent), a gemstone 4 as shown in the inlay or adhered on the substrate 2, an element made of a metallic material, a resin, a composite material, wood, a nacre, etc. It can also be a light-emitting element such as an LED. Figure 1

[0031] The decoration is made or mounted on the black coating or on the parts of the substrate that are not coated with the black coating. These parts can be free of the black coating from the start or the coating can be selectively removed by mechanical machining, by laser or by ion or electron bombardment for functional or aesthetic reasons. A pulsed laser, in particular a picosecond, nanosecond or femtosecond laser, is chosen to selectively ablate the black coating.

[0032] The decoration can be structured on the substrate by a printing method such as pad printing, digital printing or additive manufacturing. For variants in which the decoration is produced on parts not coated with the black coating, even on a metal substrate, they can also be structured by electroforming or by hot forming of amorphous metals. The decoration can also be mounted by adhesion.

[0033] According to a variant of the invention, the decoration can also be arranged under a discontinuous coating of the black coating. Thus, the component comprises a decoration of the surface of the substrate, for example a metallic coating, a resin or a lacquer, including a luminescent lacquer. The black coating is then deposited on the decoration and is selectively removed at the chosen locations to reveal the decoration, thus forming a striking contrast. Optionally, other decorations can be structured or mounted above the black coating.

[0034] ​The present invention also relates to an assembly comprising a first component and a second component, each of which is used for internal assembly or mechanism of a timepiece or jewelry. According to the present invention, the first and second components include at least one portion coated with a black coating. Preferably, the first component is capable of relative movement with respect to the second component and is mounted facing the latter. The first component is decorated. For example, the first component is a black-coated and decorated hand, and the second component is a black-coated dial. For example, the hand is decorated with a gemstone set in or glued to the tip of the hand.

[0035] Different variants for producing the component according to the invention are Figures 2A to 6 Indicated in.

[0036] The method for preparing the component comprises at least:

[0037] - Step a) providing a substrate 2 and processing said substrate. Figure 2B As schematically shown in FIG, the substrate 2 may have a relief structure after processing.

[0038] - Step b) Providing, on at least a portion of the substrate 2 , a black layer 3 mainly comprising one or more aluminum oxides.

[0039] Optionally, during step a), the substrate may be pre-treated by micro-sandblasting or micro-shot blasting to increase the surface roughness (step not shown). The surface thus treated has a roughness Ra (arithmetic mean roughness) measured with an Altisurf 500 optical profiler (ISO 4288: 1996 / 4287: 1997) between 0.4 and 5 microns and preferably between 0.4 and 2 microns.

[0040] As a variant, always optional, the substrate can undergo an electrolytic oxidation pretreatment, either an anodic treatment using electrolytic plasma or a ceramicizing type, to give the surface of the component a rough black appearance (step not shown). For this variant, the substrate is preferably made of a titanium alloy, such as Ti-6Al-4V or Ti-CP3, an aluminum alloy, such as AA6061, AA2024, AA6082, a mixed aluminum-titanium alloy, or an aluminum-lithium alloy. After this pretreatment, the substrate is treated under vacuum to deposit an ultra-black coating on the surface.

[0041] Step b) may comprise the step of depositing a black layer on the substrate by PVD, CVD or PECVD. Alternatively, the black coating is deposited on a film or strip type carrier by PVD, CVD or PECVD and then bonded to the substrate ( Figure 5 5). The film or tape may be made of a polymer or metallic material containing an adhesive on the side opposite to the coating intended to be fixed to the substrate.

[0042] The manufacturing method can also comprise a decoration step c) before and / or after step b). The decoration step can comprise the construction of a decoration on the coated or uncoated part by a printing method or by electroforming. The decoration step can also comprise the mounting of a decoration on the coated or uncoated part, the decoration being able to be fixed, for example by gluing.

[0043] According to the variants in Figure 3 , 4A , 4B and 6, there is at least one decoration step c) after the deposition of the black coating 3 in step b). As illustrated in Figure 4A , 4B and 6, this decoration step c) can be preceded by a step d) of selective removal of the black coating 3 on the areas intended to be decorated in step c). This selective removal can be limited to the black coating 3 ( Figure 4A and Figure 6 ) or extend up to the substrate 2 ( Figure 4B ).

[0044] As a variant, as illustrated in Figure 6 , the method can comprise a decoration step c) before the step b) of deposition of the black layer 3. The substrate is machined and decorated with a first decoration 4. This decorated substrate is then coated with a black coating 3 in step b), the black coating 3 being selectively removed in step d) to make the first decoration 4 visible on certain parts. The manufacturing method can comprise a second decoration step c) on the parts comprising the black coating 3. Preferably, the second decoration 4 only partially covers the black layer 3.

[0045] For all variants, the method can also comprise an additional step (not shown) of deposition of a hard protective coating on the black layer with or without decoration. This coating is an ALD (Atomic Layer Deposition) type transparent coating based on metal oxides such as Ti02, AI2O3, Si02or a mixture of at least two of these oxides. The thickness of this hard coating is between 5 and 100 nm, preferably between 5 and 20 nm.

[0046] LEGEND

[0047] (1) watch face

[0048] (2) substrate

[0049] (3) black layer

[0050] (4) decoration, also called first decoration or second decoration

Claims

1. A component for an interior assembly or mechanism of a watch or jewellery, comprising a substrate (2), the substrate comprising at least one portion coated with a black layer (3), the black layer (3) comprising at least one aluminium oxide, the coated portion having an L* value of less than 12 in the CIELAB colour system, an a* value between -2 and +2, a b* value between -3.5 and +5, the black layer (3) having a reflectivity of less than 1.5%, characterised in that The black layer (3) comprises at least 90% by weight of aluminum oxide having an aluminum content of 45% to 65% by weight, and has a thickness of 1 to 50 micrometers.

2. The component according to claim 1, characterized in that The coated portion has an L* value of less than 7 in the CIELAB color system, an a* value between -1 and +1, and a b* value between -3.5 and +1.

3. The component according to claim 1 or 2, characterized in that The black layer (3) contains 100% by weight of aluminum oxide.

4. The component according to claim 1 or 2, characterized in that The alumina has an aluminum content of 45-50% by weight.

5. The component according to claim 1 or 2, characterized in that The black layer (3) has a thickness of 2 to 10 micrometers.

6. The component according to claim 1 or 2, characterized in that The black layer (3) has a thickness of 4 to 7 micrometers.

7. The component according to claim 1 or 2, characterized in that It comprises a decoration (4) on a portion coated with a black layer (3) or on another portion of a substrate (2) without a black layer (3).

8. The component according to claim 1 or 2, characterized in that It comprises a further decoration (4) arranged between a substrate (2) and a black layer (3), said black layer (3) being discontinuous so as to make said further decoration (4) visible.

9. The component according to claim 8, characterized in that The other decoration (4) is a metal coating, resin or paint, including photoluminescent paint.

10. The component according to claim 7, characterized in that The decorative object (4) is made of metal, polymer, composite material, wood or nacre or is characterized in that it comprises an LED.

11. The component according to claim 7, characterized in that The decoration (4) is a time mark or a gemstone adhered or set on the substrate (2).

12. The component according to claim 11, characterized in that The time scale is photoluminescent.

13. The component according to claim 1 or 2, characterized in that The black layer (3) is coated with a protective layer based on metal oxides.

14. The component according to claim 13, characterized in that The protective layer contains TiO2, Al2O3 and / or SiO2.

15. The component according to claim 1 or 2, characterized in that It is selected from the group comprising dial, flange, hour-markers, hands, appliqués, rotor, plate and bridges.

16. The component according to claim 1 or 2, characterized in that The substrate (2) comprises a relief structure on its coated portion.

17. An assembly comprising a component according to any one of claims 1 to 16 and another component for an interior fitting or mechanism for a timepiece or jewellery, said other component being at least partially coated with the black layer (3).

18. The assembly according to claim 17, wherein The other component is arranged facing the component and is installed in a manner of relative movement relative to the component, and the other component includes a decorative object (4).

19. An assembly according to claim 17 or 18, characterized in that The other component is a hand and the component is a dial, the hand comprising an ornament (4) formed of a gemstone.

20. A timepiece or piece of jewellery comprising a component according to any one of claims 1 to 16 or an assembly according to any one of claims 17 to 19.

21. Method for producing a component for an interior assembly or mechanism of a watch or jewellery according to any one of claims 1 to 16, said component comprising a substrate (2) at least partially coated with a black layer (3) comprising aluminium oxide, the method comprising: - step a) providing the substrate (2) and processing the substrate (2), - Step b) Adding a black layer (3) to at least a portion of the substrate (2).

22. The preparation method according to claim 21, characterized in that Step b) of adding the black layer (3) is a step of depositing the black layer (3) on the substrate (2) or a step of placing a film or strip coated with the black layer (3) on the substrate (2).

23. The preparation method according to claim 21 or 22, characterized in that It comprises a decoration step c) before and / or after step b).

24. The preparation method according to claim 23, characterized in that Step c) consists in producing the decoration ( 4 ) by additive manufacturing, digital printing, pad printing, thermoforming, electroforming, or in installing the decoration ( 4 ).

25. The preparation method according to claim 21 or 22, characterized in that It comprises a step d) of selectively removing the black layer (3) after step b).

26. The preparation method according to claim 25, characterized in that The selective removal extends into the substrate (2).

27. The preparation method according to claim 25, characterized in that The selective removal is performed using a pulsed laser.

28. The preparation method according to claim 25, characterized in that It comprises in sequence a decoration step c), a step b) of adding a black layer (3) and a step d) of selectively removing the black layer (3) to make partially visible the decoration (4) deposited in step c).

29. The preparation method according to claim 28, characterized in that It comprises a further decoration step c) on the black layer (3) after step d).

30. The preparation method according to claim 21 or 22, characterized in that The black layer (3) is deposited by PVD, CVD or PECVD.

31. The preparation method according to claim 21 or 22, characterized in that The substrate (2) undergoes a micro-sandblasting or micro-shot blasting pre-treatment during step a) to increase the surface roughness, wherein the roughness Ra is between 0.4 and 5 micrometers.

32. The preparation method according to claim 31, characterized in that The roughness Ra is between 0.4-2 microns.

33. The preparation method according to claim 21 or 22, characterized in that The substrate ( 2 ) undergoes during step a) an anodic treatment by electrolytic plasma or an electrolytic oxidation pretreatment of the ceramizing type.

34. The preparation method according to claim 21 or 22, characterized in that It comprises a step of depositing a protective layer based on metal oxide after step b).

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