WO2024028403A1

WO2024028403A1 - Timepiece component and method for manufacturing such a timepiece component

Info

Publication number: WO2024028403A1
Application number: PCT/EP2023/071448
Authority: WO
Inventors: Pierre Huguet; Pierre Di Luna; Maria Isabel BORGES MACHADO; Ollivier Pujol
Original assignee: Rolex Sa
Priority date: 2022-08-02
Filing date: 2023-08-02
Publication date: 2024-02-08

Abstract

Timepiece component (1) comprising: - a substrate (11) made of an at least partially transparent material, - a first coloured enamel layer (12) applied to the substrate (11), in particular applied by transfer to the substrate (11), in particular by chromo decal onto the substrate (11), and - a second finishing layer (13), in particular a second opacifying finishing layer (13), applied at least partially to the first coloured enamel layer (12).

Description

Watch component and process for producing a watch component.

The invention relates to a watch component. The invention also relates to a timepiece comprising such a timepiece component. The invention finally relates to a method for producing such a watch component.

In watchmaking, particularly in watchmaking, it is sought to obtain in a reliable, robust and repeatable manner, a decorated and unalterable bezel disc, that is to say whose decorations can be varied without limitation. of the choice of colors or their associations, for a monochrome or multicolored result, according to any design, while being resistant to aging and environmental stresses (scratches, UV rays, etc.), and this without the architecture of the pieces d watchmaking does not have to be adapted to achieve these objectives.

Documents CH707424A2 and CH707423A2 describe the production of technical ceramic components (alumina or zirconia, for example), opaque, with decorations produced by impregnation of metallic salts on the face of the component visible to the user of the timepiece. It is difficult with the processes described to obtain all color combinations.

Patent EP1734420B1 describes a transparent watch crystal, locally enameled on its underside, so as to help hide the system for assembling the glass to the middle. In this patent, the main claim is for a waterproof case comprising a middle part and a bottom delimiting a compartment closed by a glass, made of a transparent material resistant to a temperature above 500°C, glued or welded at the level of the joint areas covering at least partially the scope of the middle, characterized in that the internal face of the glass has an enamel deposit formed at the joint areas.

Patent CH320817 describes a rotating bezel comprising a transparent disc whose lower face is both:

- hollowed out in order to form indexes (signs), the hollows being coated with a metallic deposit coloring the indexes, and

- coated, for example with a varnish, in order to give a colored appearance to the disc apart from the recesses.

The transparent disc reveals signs of metallic color, contrasting with the color applied to its underside. An example is given, in which this color is that of a varnish.

Document W02006/133810A1 discloses a component comprising a transparent substrate decorated using layers of enamel placed in recesses, as well as their method of obtaining. Variations in enamel shades described in this document are generated by variations in enamel thickness, controlled by the depth of the recesses in which it is deposited (these recesses may be on the faces and/or on the side of the enamel). components). We thus obtain a variation of shades for a single enamel composition.

The aim of the invention is to provide a watch component making it possible to improve the components known from the prior art. In particular, the invention proposes a watch component that can be decorated in a simple manner and offering great durability of the decorations made on the component without it being necessary to design the rest of the timepiece, with dedicated means to spare and protect the decorated surface. According to a first aspect of the invention, objects are defined by the following propositions.

1. Watch component (1) comprising:

- a substrate (11) made of at least partially transparent material, and

- a first layer of colored enamel (12) applied by transfer to the substrate (1 1), in particular by decaling a chromo on the substrate (1 1).

2. Watch component (1) according to proposition 1, characterized in that the watch component (1) comprises a second finishing layer (13), in particular a second layer (13) of opacifying finishing, applied at least in part to the first layer of colored enamel (12).

3. Watch component (1) according to proposition 1 or 2, characterized in that the substrate is made of an inorganic material such as a technical ceramic, a quartz, a spinel, a magnesium aluminate, an AION, a YAG, a cubic zirconia , a mineral glass, a polycrystalline alumina, a glass ceramic, a monocrystalline alumina and/or in that the substrate has at least locally a value of the real in-line transmission or Real In-line Transmittance for light having a wavelength of 550 nm greater than 60% or 70% or 80% or 85%.

4. Watch component (1) according to one of propositions 1 to 3, characterized in that the substrate has a hardness greater than 800 Hv or 1000 Hv. Watch component (1) according to one of propositions 1 to 4 and according to proposition 2, characterized in that the second finishing layer is:

- a layer of enamel, in particular a layer of enamel applied by transfer, and/or

- a metal-based layer, in particular deposited by PVD, CVD, ALD, PLD, and/or

- a layer of another coating, such as paint. Watch component (1) according to one of propositions 1 to 5, characterized in that the watch component (1) is an external covering component for a timepiece (100), such as in particular:

- an ice cream,

- a fund,

- a bezel disc,

- a bracelet element, or

- a middle part, or in that the watch component (1) is an internal component for a timepiece (100), such as in particular:

- a dial,

- a flange, or

- a disk displaying horological information. Watch component (1) according to one of propositions 1 to 6, characterized:

- in that the substrate (1 1) comprises a first surface (11 1) and a second surface (1 12), in particular a second surface (1 12) parallel or substantially parallel to a first surface (1 1 1), - in that the first layer (12) and/or the second layer (13) are applied to the first surface (1 11), and

- in that the first surface (1 1 1), in particular the first layer and/or the second layer applied to the first surface, is visible through the second surface (1 12) and the substrate (1 1). . Watch component (1) according to proposition 7, characterized in that the substrate (1 1) comprises at least one second recess (15) made on the second surface (1 12), in particular at least one second recess (15) made by laser machining. . Watch component (1) according to proposition 8, characterized in that the at least one second recess (15) is coated, in particular coated with a metal-based layer, in particular coated with a metal-based layer deposited by PVD , CVD, ALD or PLD. 0. Watch component (1) according to one of propositions 7 to 9, characterized in that the substrate (1 1) has an anti-reflective treatment on the second surface (1 12). 1. Watch component (1) according to one of propositions 1 to 10 and according to proposition 7, characterized in that the substrate (1 1) comprises at least a first recess (14) made on the first surface (1 1 1) after application of the first and second layers, in particular at least one first recess (14) produced by laser machining. Watch component (1) according to proposition 1 1, characterized in that the at least one first recess (14) is coated, in particular coated with a metal-based layer, in particular coated with a metal-based layer deposited by PVD, CVD, ALD or PLD. Watch component (1) according to proposition 1 1 or 12, characterized in that the at least one first recess (14) is such that the area of material ablated at the level of a plane perpendicular to a direction in which is made the at least one first hollow, arranged between:

- the surface from which the at least one first recess is made, in particular the lower surface (1 1 1) or a surface of the first layer (12) or a surface of the second layer (13), and

- a surface defining the bottom of the at least one first hollow, is scalable according to the direction in which the at least one first hollow is made, and/or is such that the area of material ablated at the level of a plane any parallel to the direction in which the at least one first recess is made is progressive in a direction orthonormal to the direction in which the at least one first recess is made. Watch component (1) according to one of propositions 11 to 13, characterized in that the at least one first recess (14) has a millimetric or micrometric or nanometric area, in particular at the level of a surface defining the bottom of the hollowing and/or at the level of the surface from which it is carried out. Method for producing a watch component (1), the method comprising the following steps:

- provision of a substrate (11) made of at least partially transparent material, and

- application of a first layer of colored enamel (12) to the substrate (11) by transfer, in particular by decaling a chromo on the substrate (11). Production method according to proposition 15, characterized in that the method comprises an application of a second finishing layer (13), in particular a second layer (13) of opacifying finishing, at least partly on the first layer of colored enamel (12). Production method according to proposition 16, characterized in that the application of the second layer is:

- an application of a layer of enamel, in particular a layer of enamel by transfer, in particular by decal of a chrome, and/or

- an application of a metal-based layer, in particular by PVD, CVD, ALD, PLD, and/or

- application of a layer of another coating, such as paint. Production method according to one of propositions 15 to 17, characterized in that it comprises a step of producing at least one first recess (14) on a first surface (111) of the substrate (1 1), in particular at least one first recess (14) produced by laser machining, and/or in that it comprises a step of producing at least one second recess (15) on a second surface (1 12) of the substrate (1 1), in particular at least one second recess (15) produced by laser machining. Production method according to proposition 18, characterized in that the step of producing at least one first hollowing and/or the step of producing at least one second hollowing are carried out after the step of applying the first layer of enamel (12) on the substrate (11), and in that, in the step of producing at least one first hollow and/or in the step of producing at least one second hollow, a decoration formed by the first layer of enamel is used as a reference, in particular as a machining reference. Production method according to one of propositions 18 and 19, characterized in that the method comprises a step of coating the at least one first recess (14) and/or the at least one second recess (15), in particular by a metal-based layer, in particular by a metal-based layer deposited by PVD, CVD, ALD or PLD. Watch component (1) obtained by implementing the method according to one of propositions 15 to 20. Timepiece (100) comprising a watch component (1) according to one of propositions 1 to 14 and 21, in in particular a watch component (1) according to one of propositions 7 to 14 arranged so that the first surface (1 1 1), in particular the first layer (12) and/or the second layer (13), is visible through the second surface (1 12) and the substrate (1 1) by the wearer of the timepiece (100).

According to a second aspect of the invention, objects are defined by the following propositions.

23. Watch component (1) comprising:

- a substrate (1 1) made of at least partially transparent material,

- a first layer of colored enamel (12) applied to the substrate (1 1), in particular applied by transfer to the substrate (1 1), in particular by decaling a chromo on the substrate (1 1), and

- a second finishing layer (13), in particular a second layer (13) of opacifying finishing, applied at least in part to the first layer of colored enamel (12).

24. Watch component (1) according to proposition 23, characterized in that the substrate is made of an inorganic material such as a technical ceramic, a quartz, a spinel, a magnesium aluminate, an AION, a YAG, a cubic zirconia, a mineral glass, a polycrystalline alumina, a glass ceramic, a monocrystalline alumina and/or in that the substrate has at least locally a value of the real in-line transmission or Real In-line Transmittance for light having a wavelength of 550 nm greater than 60% or 70% or 80% or 85%.

25. Watch component (1) according to one of propositions 23 to 24, characterized in that the substrate has a hardness greater than 800 Hv or 1000 Hv. Watch component (1) according to one of propositions 23 to 25, characterized in that the second finishing layer is:

- a metal-based layer, in particular deposited by PVD, CVD, ALD, PLD, and/or

- a layer of another coating, such as paint. Watch component (1) according to one of propositions 23 to 26, characterized in that the watch component (1) is an external covering component for a timepiece (100), such as in particular:

- an ice cream,

- a fund,

- a bezel disc,

- a bracelet element, or

- a dial,

- a flange, or

- a disk displaying horological information. Watch component (1) according to one of propositions 23 to 27, characterized:

- in that the substrate (1 1) comprises a first surface (11 1) and a second surface (1 12), in particular a second surface (1 12) parallel or substantially parallel to a first surface (1 1 1),

- in that the first layer (12) and/or the second layer (13) are applied to the first surface (1 11), and

- in that the first surface (1 1 1), in particular the first layer and/or the second layer applied to the first surface, is visible through the second surface (1 12) and the substrate (1 1). Watch component (1) according to proposition 28, characterized in that the substrate (1 1) comprises at least one second recess (15) made on the second surface (1 12), in particular at least one second recess (15) made by laser machining. Watch component (1) according to proposition 29, characterized in that the at least one second recess (15) is coated, in particular coated with a metal-based layer, in particular coated with a metal-based layer deposited by PVD , CVD, ALD or PLD. Watch component (1) according to one of propositions 28 to 30, characterized in that the substrate (1 1) has an anti-reflective treatment on the second surface (1 12). Watch component (1) according to one of propositions 23 to 31 and according to proposition 28, characterized in that the substrate (1 1) comprises at least a first recess (14) made on the first surface (1 1 1) after application of the first and second layers, in particular at least one first recess (14) produced by laser machining. Watch component (1) according to proposition 32, characterized in that the at least one first recess (14) is coated, in particular coated with a metal-based layer, in particular coated with a metal-based layer deposited by PVD, CVD, ALD or PLD. Watch component (1) according to proposition 32 or 33, characterized in that the at least one first recess (14) is such that the area of material ablated at the level of a plane perpendicular to a direction in which the 'at least a first hollow, arranged between:

- a surface defining the bottom of the at least one first hollow, is scalable according to the direction in which the at least one first hollow is made, and/or is such that the area of material ablated at the level of a plane any parallel to the direction in which the at least one first recess is made is progressive in a direction orthonormal to the direction in which the at least one first recess is made. Watch component (1) according to one of propositions 32 to 34, characterized in that the at least one first recess (14) has a millimetric or micrometric or nanometric area, in particular at the level of a surface defining the bottom of the hollowing and/or at the level of the surface from which it is carried out. Method for producing a watch component (1), the method comprising the following steps:

- supply of a substrate (1 1) made of at least partially transparent material,

- application of a first layer of colored enamel (12) on the substrate (11), in particular application of the first layer of colored enamel (12) on the substrate (11) by transfer, in particular by decal of a chromo on the substrate (1 1), and

- application of a second layer (13) of finishing, in particular of a second layer (13) of opacifying finishing at least partly on the first layer of colored enamel (12). Production method according to proposition 36, characterized in that the application of the second layer is:

- application of a layer of another coating, such as paint. Production method according to one of propositions 36 and 37, characterized in that it comprises a step of producing at least one first recess (14) on a first surface (11 1) of the substrate (1 1), in particular at least one first recess (14) produced by laser machining, and/or in that it comprises a step of producing at least one second recess (15) on a second surface (1 12) of the substrate (1 1), in particular at least one second recess (15) produced by laser machining. Production method according to proposition 38, characterized in that the step of producing at least one first hollowing and/or the step of producing at least one second hollowing are carried out after the step of applying the first layer of enamel (12) on the substrate (11), and in that, in the step of producing at least one first hollow and/or in the step of producing at least one second hollow, a decoration formed by the first layer of enamel is used as a reference, in particular as a machining reference. Production method according to one of propositions 38 and 39, characterized in that the method comprises a step of coating the at least one first recess (14) and/or the at least one second recess (15), in particular by a metal-based layer, in particular by a metal-based layer deposited by PVD, CVD, ALD or PLD. Watch component (1) obtained by implementing the method according to one of propositions 36 to 40. Timepiece (100) comprising a watch component (1) according to one of propositions 25 to 35 and 41, in in particular a watch component (1) according to one of propositions 30 to 35 arranged so that the first surface (1 1 1), in particular the first layer (12) and/or the second layer (13), is visible at through the second surface (1 12) and the substrate (1 1) by the carrier of the timepiece (100). Figure 1 is a schematic view of an embodiment of a timepiece according to the invention, view in which a watch component is shown in section.

One embodiment of a timepiece 100 is described below in detail with reference to Figure 1.

The timepiece 100 is for example a watch, in particular a wristwatch. Timepiece 100 includes a set including:

- a watch movement, and

- a dial.

The assembly is intended to be mounted in a timepiece case or box in order to protect it from the external environment.

The watch movement can be a mechanical movement, in particular an automatic movement, or even a hybrid movement. Alternatively, the movement may be an electronic movement.

The timepiece 100, in particular the assembly or the case or the dial or the movement, comprises a timepiece component 1. The timepiece component 1 can for example be an external trim component for a timepiece 100, such as in particular:

- an ice cream,

- a fund,

- a bezel disc,

- a bracelet element, or

- a build. Alternatively, watch component 1 can be an internal component for timepiece 100, such as:

- a dial,

- a flange, or

- a disk displaying horological information.

Watch component 1 includes:

- a substrate 1 1 made of at least partially transparent material, and

- a first layer of colored enamel 12 applied, in particular by transfer, to the substrate 1 1, in particular to a first surface 11 1 of the substrate 1 1.

By “colored enamel layer”, we mean a layer of enamel having a coloration visible to the naked eye, regardless of the color of this area. The color can thus be achromatic (white, gray or black). Thus, a “colored layer” generally provides its color to the watch component or contributes to the color of the watch component. The final color or resulting color of the watch component is then a combination of the color of this colored layer, nuanced by that of a possible second finishing layer and that of the substrate if it is not colorless. Preferably, the substrate is colorless, and the resulting color of the watch component is the resulting shade of the first enamel layer 12 and the possible second finishing layer 13. Preferably, the substrate is sapphire, an alumina monocrystalline and colorless, and the resulting color of the watch component is the resulting shade of the first layer of enamel 12 and of the possible second finishing layer 13.

Preferably:

- the watch component comprises the first layer of colored enamel 12 applied by decaling a chromo on the substrate 11, in particular on the first surface 1 1 1 of the substrate 1 1, and/or

- the watch component comprises the second layer 13 for finishing or supporting the decoration or opacifying. The second layer 13 is applied at least partly on top of the first layer 12. The function of the second layer 13 is in particular to support the color of the colored enamel.

By “finishing layer”, we mean the second of the two layers of the envisaged stack, that is to say the one with which the stack is finished or the one which covers the first layer. Where there is a first coat and a top coat, the first coat is sandwiched between the substrate and the top coat. The finishing layer has the function of being a support layer or an opacifying layer, that is to say to reduce or eliminate the transparency of the decoration formed by the colored layer or more generally, to support the color of the first colored layer.

By “support layer” we mean a layer which intensifies or modifies the color of the first layer.

By “opaque layer” or “opacifying layer” is meant a non-transparent layer, in particular an enamel layer being non-transparent. An opacifying layer reduces the transparency of the assembly that it forms with the structure to which it is applied, compared to the transparency of this structure alone. An opaque layer removes all transparency from the whole that it forms with the structure on which it is applied, whatever the transparency of this structure. In practice, you cannot see through an opaque layer. In the timepiece 100, the component is advantageously arranged so that the first layer 12 and/or the second layer 13 is visible through the substrate 11 by the wearer of the timepiece 100. in other words, the wearer or user of the watch advantageously sees the side of the first layer in contact with the substrate 1 1, this vision being achieved through the substrate. The component is made so as to be arranged in such a configuration.

The first layer and/or the second layer create a decoration, that is to say, preferably:

- a graphic element, or

- a pattern, or

- a combination of several graphic elements and/or patterns, or

- a complex design.

This decoration can be monochrome or formed by several colors.

The primary function of these first layer and/or second layer is decorative. They can completely hide the elements behind watch component 1 or reveal certain areas using transparency.

According to a variant, when the watch component 1 is mounted in the rest of the timepiece, no element comes to support:

- against the second layer 13, or

- against the first layer 12 in the absence (possibly local) of second layer.

The watch component 1 generally has the shape of the substrate, the substrate 11 mainly constituting the watch component 1. As shown in Figure 1, the substrate 11 comprises a first surface 111 and a second surface 112, in particular first and second surfaces 111, 112 parallel or substantially parallel. The first and second surfaces 1 1 1, 1 12 can each be of any nature, in particular planar, frustoconical, torus portion, recessed convex or projecting convex.

In Figure 1, by way of example, the surfaces 1 1 1 and 1 12 form faces of the component. These faces are parallel. Alternatively, they might not be parallel. Preferably, in the hypothesis of a watch component 1 consisting of a bezel disc, the first and second surfaces are for example two parallel or substantially parallel frustoconical surfaces.

We note, in Figure 1, that the first layer 12 has been applied to the first surface 11 1. The first layer may have been applied to the entire first surface 11 1 or to only part of the first surface 1 1 1 as shown in Figure 1.

Likewise, we note in this figure 1 that the second layer 13 has been applied directly above the first surface 1 1 1, on the assembly formed by a portion of the first surface 1 1 1 of the substrate and the first layer 12. The second layer, like the first layer, can be applied directly to the entire first surface 1 11 or directly to only part of the first surface 11 1, as shown in Figure 1.

It follows that, depending on the regions of the first surface, it is possible to encounter, in the material of the watch component, starting from the first surface 1 11 and moving towards the outside of the component (perpendicular to the first surface 1 1 1):

- the first layer 12, then the second layer 13, or

- the first layer 12 only, or

- the second layer 13 only, or

- no layer (the substrate not being coated in the region considered of the first surface 1 1 1).

Due to the transparency of the substrate 11, the first surface 111, in particular the first layer 12 and/or the second layer 13 applied to the first surface, is visible through the second surface 112 and the substrate 1 1.

Preferably, the substrate is made from or from an inorganic material such as:

- technical ceramics,

- a quartz,

- a spinel,

- a magnesium aluminate,

- an AION (an aluminum oxynitride),

- a YAG (Yttrium Aluminum Garnet),

- a cubic zirconia,

- a mineral glass,

- a polycrystalline alumina,

- a glass ceramic,

- a monocrystalline alumina (sapphire).

Preferably, the first surface 1 1 1 has a mirror polished surface state and/or the second surface 112 has a mirror polished surface state. However, at least one of the first surface 1 1 1 and second surface 1 12 may have a rougher surface state, for example a frosted surface state. This rough surface state can in particular be obtained by sandblasting and/or satin-finishing and/or brushing; it can be carried out using a traditional tool and/or using a laser. This makes it possible to give a matte appearance to the watch component 1. Alternatively, this makes it possible to give a matte appearance to at least part of the watch component 1, part of the watch component at which the rough surface condition is produced.

The substrate is at least partially transparent. Preferably, the substrate is transparent and colorless. More generally, the substrate can be made of a material that is at least partially transparent.

By “at least partially transparent” we mean that:

- the substrate comprises at least one transparent region, and/or

- at least one region of the substrate or the entire substrate having a certain degree of transparency, part of the light not being transmitted through the substrate. This covers, for example, translucent substrates or whose “Real In-line Transmittance to light having a wavelength of 550 nm is greater than 60%, or even 70%, or even 80%, or even 85%”. In other words, there is at least one place on the substrate where at least 60%, or even at least 70%, or even at least 80%, or even at least 85%, of light whose wavelength is 550 nm can pass through. the substrate from the second surface to the first surface. According to the reference article E6418 v1, extracted from the work “Les Techniques de l’environnement” and entitled “Transparent ceramics - General characteristics and manufacturing processes”, by Rémy Boulesteix and Alexandre Maitre (10.07.2018), transparency can in fact be characterized by measuring the “real online transmission” of light, designated by its English acronym RIT (Real In-line Transmission). It is performed with an angle low aperture (around 0.5°) with a spectrophotometer. It corresponds to the ratio of the intensity of light transmitted through a sample of material to the incident intensity. This RIT transparency is a function of the thickness of the sample passed through (x), the wavelength (X) of the light and is given by the Beer-Lambert law.

RIT(X) = [1 -Rs(X)].e' ^{a(X) x}

Rs are the losses due to reflection from the two surfaces of the sample; they are of the order of 0.14 to 0.16, and can be evaluated using the formula:

Rs = 2.R'(X) /[1 +R'(X)] where, at normal incidence, R'={[n(X) -1 ]/[n(X) +1 ]} ²

With n, the refractive index of the material and a(X), the attenuation coefficient of the material, which takes into account the optical losses induced by the various sources of dispersion or absorption of light passing through the material.

For example, the substrate may be colored.

Modes of execution of a method for producing a watch component 1 as mentioned above are described below.

Generally speaking, the production process comprises the following steps:

- supply of a substrate 1 1 made of at least partially transparent material, and

- application of a first layer of colored enamel 12 on a surface of the substrate 1 1, in particular by transfer.

Preferably:

- the application of the first layer of colored enamel 12 on the substrate 11 can be produced by decaling a chromo on the substrate 11, in particular on the first surface 1 1 1 of the substrate 1 1, and/or

- the process may include an application of a second finishing layer 13 at least partly on the first layer of colored enamel 12.

In other words, a solution subject of this document is based on a particular use of the enamel deposited by means of chromo (enamel decal; we specify that the expressions "enamel decal" and "chromo decal> > are considered equivalent) on a surface intended to be seen by the user of the watch through the substrate 1 1. Preferably, this is implemented in two stages:

- the first layer of enamel, colored, visible through the substrate, represents the decoration,

- a second finishing layer of enamel removes the transparency of the decoration or more generally, supports the color of the first layer of colored enamel. Preferably, the second layer of enamel is opaque. Preferably, the second layer of enamel is opaque and white.

This makes it possible to obtain a decorated and unalterable watch component (for example a bezel disc) in a reliable, robust and repeatable manner.

Depending on the embodiments, the second finishing or decor support or opacifying layer can be:

- a layer of enamel, in particular a layer of enamel applied by transfer, in particular by chromo decal, and/or

- a metal-based layer, in particular deposited by PVD, CVD, ALD, PLD, and/or

- a layer of another coating, such as paint. Preferably, according to the invention, to produce the watch component 1, for example to produce a bezel disc, we proceed as follows:

- we obtain a transparent substrate, preferably sapphire,

- an enamel decoration is applied by decaling a chromo on a surface of the substrate intended to be seen through the substrate,

- a finishing or supporting or opacifying layer is applied over the enamel decoration.

On the contrary, in a traditional manner, to produce the watch component 1, in particular to produce a bezel disc,

- we obtain a substrate (generally opaque, for decorative watchmaking purposes),

- an undercoat is optionally applied to the surface of the substrate which would be seen by the user in the absence of a coating on this surface,

- an enamel decoration is applied to said surface of the substrate possibly previously covered with the undercoat,

- we apply a glaze (colorless transparent enamel) to the enameled decoration.

In the case of use of the watch component in the exterior casing of the watch, we note that the exterior surface of the component can very frequently be subject to attacks from the external environment. This may harm the lasting integrity of the decor if it is placed on this exterior surface. The solutions according to the invention offer solutions to this problem by exposing the bare surface of the component to these attacks, thus protecting the decoration placed on a more sheltered surface and visible by transparency through the substrate.

More specific implementations are described in more detail below. In a first step, we obtain a substrate 11 to decorate. The substrate constitutes a part of the watch component 1 and, preferably, the majority of the watch component 1.

This substrate must withstand the glazing conditions. Thus, it must withstand temperatures above 500°C, preferably above 750°C, allowing the vitrification of the enamel, without suffering damage such as deformation or oxidation.

Preferably, the substrate must also have sufficient hardness to be able to resist abrasion. The material of which the substrate is made preferably has a Vickers hardness greater than 800 Hv, or even greater than 1000 Hv. This is all the more important if the component is an exterior covering component which can be exposed to mechanical attack.

In a second step, the first layer of enamel is applied. To do this, the decoration is applied to the substrate 1 1, in particular to the first surface 1 1 1 of the substrate 1 1. Preferably, this decoration is applied by decal. Preferably, one or more chromos are applied by decal on the substrate 1 1, in particular on the first surface 1 1 1 of the substrate 1 1, that is to say that a layer of enamel is applied by decal of one or more chromos. The possible different chromos (for example of different colors) can be applied to different regions of the first surface 1 11 juxtaposed or not, and/or they can be at least partially superimposed.

The decoration whose pattern is determined by the chromo is previously prepared, for example by screen printing, by lithography, by chromolithography, on transfer paper (or transfer paper). The color consists of a colored film deposited on the transfer paper, one of the faces of which is intended to come into contact with the first surface 1 1 1 of the substrate 1 1 during transfer.

The film is made of enamel powder mixed with a polymer to ensure consistency. This film can be transferred (or transferred or transported) from the transfer paper to the first surface of the substrate to create a decoration.

For example, the application of chromo is carried out by moistening it in water, in order to separate the film from the transfer paper, before or after application of the film on the substrate (depending on whether the pattern is transferred to the place where Upside down). We then remove the water and any air bubbles that may be between the substrate and the film, for example using an elastomer squeegee. Then, we leave it to dry, especially in the air.

Finally, the substrate on which the film is deposited is baked. This film is made up of enamel powder mixed with a polymer, cooking serves on the one hand to eliminate the polymer and on the other hand to vitrify the enamel. This cooking can be done in an oven, in ambient air, at high temperature. Typically, the vitrification heat treatment is obtained above 500°C, preferably above 750°C, for a period of a few minutes, typically 15 minutes. At the end of this step, the substrate is decorated with a layer of colored enamel.

The coefficient of thermal expansion of the enamel used in the chromo must be identical or very close or compatible with that of the substrate in order to guarantee a hold (adhesion) and a suitable aesthetic (i.e. not showing cracks , no shaking or chipping). There layer 12 being very thin, the tolerance on the difference in thermal expansion coefficient between this layer 12 and the substrate 11 is greater than in the case of depositing a thick layer (for example deposited by traditional enamelling): thus, in the case of a chromo, a difference of up to 5%, or even 10%, or even 15%, or even 20%, or even 25%, can be considered. A chromo layer has a thickness typically of the order of 5 to 20 pm, or even 7 to 10 pm after cooking (which can correspond to a thickness of 40 pm to 80 pm when it is raw). This is why it is considered to be thin compared to a deposited layer of enamel traditionally considered to be thick (typically, more than 100 pm, or even more than 200 pm, or even more than 300 pm after firing). The use of such thin chrome is made possible by the fact that at the same thickness, the color of the chrome is more saturated than that of a traditionally deposited enamel.

Alternatively, the enamel can be deposited by pad printing type transfer or direct screen printing type transfer to create the decoration. As a further variation, the enamel can be applied in the traditional way, with a brush for example.

Depending on the intended rendering, this step of producing the first layer can be repeated. The first layer of enamel constituting the decoration, in particular a colored decoration, can therefore be multi-layered. In this second step, baking is preferably carried out between each application of a layer of enamel on the substrate 11, in particular on the first surface 111 of the substrate 11 or on the layer previously applied. Alternatively, in this second step, a single firing can be carried out once all layers of enamel are applied. In a third optional step, the second layer 13 is applied. The second layer is preferably a finishing or support or opacifying layer. The second layer is at least translucent and ideally opacifying. Preferably again, the second layer is a uniformly white and/or opaque layer of enamel. The second layer covers at least partly the decorations constituted by the first layer constituted during the second step.

As in the second stage, after the application of the second layer, a firing is carried out leading to the vitrification of the enamel and the possible elimination of the polymer, if the enamel of the second layer is produced using a chromo.

The coefficient of thermal expansion of the enamel used for the second layer 13 must be identical or very close to or compatible with that of the layer on which it is deposited, for the reasons explained previously. For combinations of thin layers 12 and 13, the tolerance on the difference in thermal expansion coefficient between these layers and the substrate 11 is greater than in the case of deposition of a thick layer, which offers more possibilities in terms of adhesion and aesthetics.

This second layer 13 or finishing layer is preferably applied by transfer, in particular by chromo decal, as was the decoration in the second step.

Alternatively, the second layer 13 can also be applied by other techniques (pad printing, brush, screen printing, etc.). Different implementation variants can be planned in this third stage:

- The second layer can be any color. Any enamel color can be considered. The color of the second layer may be different depending on where it is applied on the decor and/or on the substrate.

- The opacity of the second layer can be varied: different levels of opacity can be considered, from translucent to completely opaque, depending on the nature of the finishing layer(s). The targeted opacity could also be different depending on the location where the finishing coats are applied on the decor, and on the substrate.

- The chemical nature of the finishing coat could be varied: any type of inorganic material meeting the criteria of opacity and resistance to environmental stress could be considered. The chemical nature of the topcoat may also be different depending on where it is applied to the decor. For example :

* enamel loaded with luminescent zirconia powder or another luminescent inorganic material, or

* metallization, or

* a layer based on metal, in particular nitrides, deposited for example by PVD (Physical Vapor Deposition), CVD (Chemical Vapor Deposition), ALD (Atomic Layer Deposition), PLD (Pulsed Laser Deposition), or any other suitable method, can be used as a finishing coat.

- The method of applying the finishing coat can thus be a method by transfer, by brush, by screen printing, PVD, CVD, ALD, PLD, etc., depending on the nature of the layer, its thickness, the level of targeted precision (in location, thickness, distribution, etc.).

- The finishing layer is at least positioned over part of the locations decorated during the second step. - The distribution of the finishing coat can be varied over the extent of the first surface 1 1 1:

* the finishing coat can only be positioned on the locations decorated during the second step, and, in this case, it can be applied to all or part of the decoration,

* the finishing layer can also be positioned on undecorated locations during the second step, and, in this case, it can be on all or part of the undecorated locations,

- The thickness of the finishing coat can be variable:

* this thickness can define its opacity level, which can be chosen depending on the location where it is applied,

* this thickness can impact the shade resulting from the stacking of the first and second layers 12 and 13.

Depending on the method of execution of the process, the application of the second layer can be:

- application of a layer of another coating, such as paint.

Many alternative embodiments can be envisaged. In particular, one or more recesses can be made on the first surface 1 1 1 of the watch component and/or one or more recesses on the second surface 1 12 of the watch component.

One or more hollows on the first surface and/or on the second surface can be made before the second and third steps mentioned above, and/or one or more recesses on the first surface and/or on the second surface can be made between the second and third steps mentioned above, and/or one or more recesses on the first surface and/or on the second surface can be made after the second and third stages mentioned above.

When a hollowing is carried out at the first surface after baking the first layer, the hollowing can affect:

- only part of the thickness of the first layer, or

- the entire thickness of the first layer, or

- the entire thickness of the first layer and part of the thickness of the substrate 11.

When a hollowing is carried out at the first surface after making the first and second layers, the hollowing can affect:

- only part of the thickness of the second layer, or

- the entire thickness of the second layer, or

- the entire thickness of the second layer and part of the thickness of the first layer, or

- the entire thickness of the second layer and the entire thickness of the first layer, or

- the entire thickness of the second layer and the entire thickness of the first layer and part of the thickness of the substrate 11.

Thus, according to the alternative embodiments, at least one first recess 14 can be made on the first surface 111, in particular at least one first recess 14 made by laser machining, and/or at least one second recess 15 can be made on the second surface 112, in particular at least one second recess 15 produced by machining laser. Preferably, the method comprises a step of coating the at least one first recess 14 and/or the at least one second recess 15, in particular by a metal-based layer, in particular by a metal-based layer deposited by PVD, CVD, ALD or PLD.

Naturally, a hollow can have any shape or geometry.

In particular, the thickness of material machined to form a hollow can be the same regardless of the location of the hollow. Thus, the depth of a dig can be constant, and the distance (measured perpendicular to the surface from which the dig is made and) which separates:

- the surface from which the hollowing is carried out (this can be the lower surface 1 1 1, just like the surface 112, or a surface of the layers 12 or 13),

- a surface defining the bottom of the recess, may be the same and correspond to the depth of the recess, regardless of the location of the recess.

Alternatively, the depth of a hollow can be progressive, that is to say it can change depending on the location(s) considered in the hollow. In particular, the height (or depth) of the sides or walls which define the contour of a hollow can change and is therefore not necessarily constant. Furthermore, the surface defining the bottom of the recess is therefore not necessarily parallel to the surface from which it is made.

The sides or walls can also form an oblique angle (constant or variable) facing for example the surface from which the hollowing is made and/or facing the surface defining the bottom digging. In other words, the angle formed by:

- the direction in which the digging is carried out, with

- the normal to the surface from which it is performed can be arbitrary, allowing all types of designs.

More generally, the area of material machined or ablated at the level of any plane perpendicular to the direction in which the digging is carried out, arranged between:

- the surface from which the hollowing is carried out (this can be the lower surface 1 1 1, just like the surface 112, or a surface of the layers 12 or 13), and

- a surface defining the bottom of the recess, may or may not be constant depending on the position considered of the plane between the surface from which the recess is made and a surface defining the bottom of the recess. In other words, the area of material ablated at the level of a plane perpendicular to the direction in which the digging is carried out, arranged between the surface from which the digging is carried out and a surface defining the bottom of the hollowing, can be evolving according to the direction in which the digging is carried out. The area of material ablated at the level of any plane parallel to the direction in which the digging is carried out may also be constant or not. In other words, the area of material ablated at the level of any plane parallel to the direction in which the digging is carried out can be evolving in a direction orthonormal to the direction in which the digging is carried out.

The areas concerned of ablated material can be of an order of magnitude millimetric (for example between 1 mm ² and 15 mm ² ), micrometric (for example between 1 pm ² and 15 pm ² ), nanometric (i.e. any surface area less than 1 pm ² ) or the affected areas of ablated material can be those of surfaces whose dimension is of an order of magnitude:

- millimetric (between 0.5 mm and 10 mm, or even between 1 mm and 5 mm), or

- micrometric (between 0.5 pm and 200 pm, or even between 1 pm and 50 pm), or

- nanometric (between 50 nm and 500 nm, or even between 200 nm and 400 nm). In other words, a recess can thus have a millimetric or micrometric or nanometric area, in particular at the level of a surface defining the bottom of the recess and/or at the level of the surface from which it is made.

These variations can be combined to create different optical effects, including producing color nuances and gradients.

Furthermore, it is specified that these machining or ablations can be carried out in the chromo both before and after firing.

Several examples are described below in detail relating to the production:

- an ice cream,

- a two-tone bezel, and

- a two-tone bezel with metallic recesses.

The first example concerns the manufacture of a watch crystal, particularly in sapphire, presenting two shades of red.

The first step is to obtain a watch crystal, for example sapphire. For example, the lower surface 111 and/or the upper surface 112 are flat. The second step consists of creating the decoration (first layer 12). In this step, we obtain a red chromo (prepared beforehand, in particular by screen printing a colored enamel on transfer paper). By dipping it in de-ionized water, the colored enamel film comes off the transfer paper. This film is then applied to the lower surface 1 1 1 of the watch crystal (side intended to be inside the watch case). The watch glass is then cooked at 800°C for 15 minutes in an oven. The temperature rise speed is rapid (around 30 minutes) and the cooling takes place over an equivalent period, so that the complete heat treatment allowing the vitrification of the enamel lasts less than an hour and a half.

The third step consists of making the finishing layer (second layer 13). In this third step, a layer of white and opaque enamel is applied to part of the decorative layer previously deposited during the second step. The finishing coat is for example a layer of enamel, applied using a chromo in the same way as the decoration during the second step. The watch glass is then typically cooked at 800°C for 15 minutes in an oven. The temperature rise speed is rapid (around 30 minutes) and the cooling takes place over an equivalent period, so that the complete heat treatment allowing the vitrification of the enamel lasts less than an hour and a half.

We then obtain a watch glass presenting two shades of red: - a first shade of red (translucent red) at the locations where only the red enamel has been applied. The appearance is translucent and clear. At the location of this part of the decor, we can see through the ice, and - a second shade of red (opaque red) where a finishing coat of opaque white enamel has been deposited on the red enamel. The appearance is red, more intense and is opaque. You cannot see through the ice at these locations.

It is thus possible to offer various decorations made according to this same principle, such as watch glasses with fine decorations that are translucent or transparent in places, and opaque in other locations which would constitute, for example, signs, graduations or indexes.

The second example concerns the manufacture of a two-tone red and black sapphire bezel disc.

In the first step, we procure a sapphire bezel disc, with a mirror-polished surface finish. Its upper surface 1 12 (the one which will be directly seen by the user when the disc is in place on the timepiece) is for example curved. The lower surface 1 1 1 (the one which will be seen indirectly, that is to say through the substrate, by the user when the disc is in place on the timepiece) is for example flat.

In the second step, we create the decoration by applying the first layer. To do this, we obtain chromos (one black and one red, prepared beforehand, in particular by enamel screen printing on transfer paper) to make the part intended to be black and that intended to be red. The chromos are soaked in de-ionized water so that the transfer papers come off the colored enamel films. These films are then placed on the lower surface 1 1 1. The black film is positioned on one half of the lower surface of the sapphire disc and the red film is positioned on the other half of the lower surface. sapphire disc. Cooking at 800°C for 15 minutes is then carried out in an oven. The temperature rise speed is rapid (around 30 minutes) and the cooling takes place over an equivalent period, so that the complete heat treatment lasts less than an hour and a half. Alternatively, a single color including a black zone and a red zone can be used.

One or more marks can be made on the substrate to help position the chromo film on the first surface 1 1 1. Advantageously, the mark(s) can be positioned on the first surface or on a surface adjacent to the first surface. Advantageously again, the mark(s) can be constituted by a material which disappears during the vitrification of the enamel.

In the third step, we make a finishing coat. To do this, a layer of white and opaque enamel is applied over the entire previously enameled part, during the second step. The finishing coat is also obtained using a chromo, applied in the same way as the decor in the second step. We then obtain a lower surface 1 1 1 seen through the substrate having a first half of opaque red color and a second half of opaque black color.

The bezel disc, with opaque decoration, can then be clipped into a steel ring to form a bezel. Possible technical parts of the bezel can be highlighted by the areas remaining transparent after the decorations made on the lower surface 1 1 1 of the disc. The third example concerns the manufacture of a two-tone red and black sapphire bezel disc with metalized recesses.

The decoration of the disc obtained in the second example described above can be continued to obtain the third example comprising hollows or metallized engravings.

We use a disk obtained according to the procedure described in the second example.

The upper surface 1 12 is then covered with a protective resin.

Then, hollows are made, in particular with a femtosecond laser on the upper surface 1 12, through the resin.

Then, a metallic coating, in particular platinum, is deposited by PVD (Physical Vapor Deposition) on the upper surface.

Then, the resin layer is dissolved. The metal covering therefore only remains at the bottom of the recesses.

We obtain a sapphire disc with a two-tone appearance, strong and opaque colors. The engraved signs (consisting of the hollows) on the upper surface 1 12 have a metallic appearance following the PVD deposition.

As in the second example, the bezel disc can then be clipped into a steel ring to form a bezel. Any technical parts can be highlighted by the areas that remain transparent after the decorations made on the lower surface. Thanks to the solutions described, it is possible to obtain both the advantages of the chromo decoration and those of the sapphire substrate, in a synergistic manner due to the innovative configuration proposed.

The chromo decoration gives access to aesthetic advantages, due to the wide range of enamel colors available, and this without design limitation (only the resolution of the chromo has to be taken into account; for example, when it is manufactured by screen printing , the resolution is that of the mesh of the chosen frame). Enamel deposited using the chromo technique has very good adhesion. To do this, however, it is necessary to adapt the thermal expansion coefficients of the enamels to that of the substrate. Enamels offer the advantage of guaranteeing possible use of the component produced over very wide temperature ranges, as well as excellent resistance to thermal shock, UV rays, humidity (even combined with high temperatures), and to chemicals. Chromo is not reserved for flat surfaces. In fact, the film can be deposited on raised surfaces (for example, it is suitable for a disc having a frustoconical or convex surface). Chromo is not reserved for surfaces delimited by partitions, because the film is a coherent object (unlike traditional enamel, deposited in the form of a fluid, so that partitions must be provided for the keep it in its intended location). Chromo deposition is more repeatable and automatable than traditional brush enamelling. It is thus possible to obtain high production quality, in series.

As a material for making the substrate 1 1, sapphire is preferred. Sapphire indeed has excellent resistance to scratches, due to its very high hardness. For the application of a watch component, the fact that the upper surface 112 of the component (that exposed to possible mechanical attack) is made of sapphire makes it possible to offer a solution at least as good as current ceramic solutions. In fact, the hardness of sapphire is equivalent to that of polycrystalline alumina used to make certain components, and greater than that of zirconia used to make other components.

Furthermore, sapphire has excellent breaking strength. To produce a watch component, the fact that the upper surface 1 12 of the component is made of sapphire makes it possible to offer a solution at least as good as the currently known solutions. Indeed, on average, the breaking stress of sapphire is -1700 MPa along the A axis and -3500 MPa along the C axis, which is greater than the breaking stress of zirconia (-1300 MPa) , itself higher than that of polycrystalline alumina (-500 MPa).

New advantages are obtained by the combination of sapphire and chromo in the innovative configuration proposed (application of chromo on a surface visible through the substrate, allowing the use of an opacifying finishing layer):

- The proposed solution, combining a sapphire and an enameled decoration, is entirely inorganic, and therefore unalterable to UV rays, over very wide temperature ranges, to humidity (even combined with high temperatures), to chemicals, without having to seal the decor. In addition, it is resistant to abrasion.

- The decoration being at a distance from the upper surface 1 12 of the substrate directly visible to the user (decor under the sapphire), the arrangement results in a visual and aesthetic effect of depth. This effect can be further amplified by the rounded hollow or convex geometry projecting from the substrate surface directly visible to the user.

- The design allows for superposition of treatments and effects. For example : * it is possible to carry out a treatment on the upper surface 1 12 of the sapphire, in particular an anti-reflective treatment, and/or

* hollows can be made on the upper surface 1 12 and/or lower surface 1 1 1 of the sapphire.

- We can choose aesthetic effects due to the colors of the colored layer and the location where we position it.

- Transparency levels and aesthetic effects can be adjusted by adjusting the opacity and color of the topcoat and the location where it is positioned. For a masking function, you can choose to create opaque layers.

The solutions described are very favorable from an industrial point of view in the sense that they make it possible to obtain high production quality due to the repeatability of the process for producing the watch component.

In particular, the solutions described allow treatment of the upper surface 112 of the sapphire after having carried out the steps of providing a substrate, applying a first layer and applying a second layer. To carry out this treatment, it is possible to take advantage of the transparency of the substrate and, consequently, to locate the treatment position of the upper surface 1 12 by locating on the decoration produced on the lower surface 1 1 1. This allows to position, by observation/recognition of the shape of the decoration, the treatment to be carried out on the upper surface. It is thus possible to make one or more recesses on the upper surface 112, at precise locations in relation to the enamel decoration previously made on the lower surface 1 1 1 of the watch component, that is to say to make one or several recesses on the upper surface 112 using a decoration formed by the first layer of enamel as a reference, in particular as a machining reference. Conversely, it is possible to create an enamel decoration on the lower surface 1 1 1 of the watch component at precise locations in relation to one or more recesses previously made on the upper surface 1 12, that is to say to produce a decoration formed by the first layer of enamel using as marks one or more recesses on the upper surface 1 12.

The solutions described also make it possible to produce a large number of component variations easily. Indeed, from a series of identical substrates 1 1 and depending on the options chosen to produce the first layer and second layer, it is possible to ultimately obtain watch components with very varied appearances.

In summary to obtain a decorated watch component, unalterable and adaptable without limitation of choice of graphic elements, patterns, shapes and colors or their associations, according to any spatial distribution, (that is to say without limitation of design) , it is proposed to produce a first layer of enamel on a partially transparent or transparent substrate, this first layer of enamel being intended to be seen through the substrate. The first layer of enamel can be produced by transfer, in particular by decaling a chromo, and/or the first layer of enamel can be at least partially covered with a second opacifying layer, in particular a second white opacifying layer.

In this document, by "transfer" is meant any process making it possible to transfer, transfer or transport enamel onto a surface to be enameled according to an already established design, that is to say already constituted before transfer, transfer or transportation. This may include:

- pad printing, or

- direct screen printing, or - programmed removal by inkjet type printing.

When it comes to transferring a film (enamel powder mixed with a polymer) from transfer paper to a surface to be enameled, this transfer can be a decal, in particular a waterslide decal.

We thus carry out a reverse use of chromo type enamelling by using the second opacifying layer to cooperate with the first layer in order to participate in creating the decoration. The user therefore sees:

- the first layer, possibly formed by the use of a chromo, through the substrate, and

- optionally, the second layer through the substrate and the first layer.

In a use according to the prior art of a chromo, the result is quite different: in fact, the user usually sees the decoration through a layer of colorless and transparent enamel (covered) covering it to protect it, the enamel being applied to an opaque substrate.

Claims

Claims: Watch component (1) comprising:

- a substrate (11) made of at least partially transparent material,

- a first layer of colored enamel (12) applied to the substrate (11), in particular applied by transfer to the substrate (1 1), in particular by decaling a chromo on the substrate (11), and

- a second finishing layer (13), in particular a second layer (13) of opacifying finishing, applied at least in part to the first layer of colored enamel (12). Watch component (1) according to the preceding claim, characterized in that the substrate is made of an inorganic material such as a technical ceramic, a quartz, a spinel, a magnesium aluminate, an AION, a YAG, a cubic zirconia, a mineral glass , a polycrystalline alumina, a glass ceramic, a monocrystalline alumina and/or in that the substrate has at least locally a value of the real in-line transmission or Real In-line Transmittance for light having a wavelength of 550 nm greater than 60% or 70% or 80% or 85%. Watch component (1) according to one of the preceding claims, characterized in that the substrate has a hardness greater than 800 Hv or 1000 Hv. Watch component (1) according to one of the preceding claims, characterized in that the second finishing layer is:

- a metal-based layer, in particular deposited by PVD, CVD, ALD, PLD, and/or

- a layer of another coating, such as paint. Watch component (1) according to one of the preceding claims, characterized in that the watch component (1) is an external covering component for a timepiece (100), such as in particular:

- an ice cream,

- a fund,

- a bezel disc,

- a bracelet element, or

- a dial,

- a flange, or

- a disk displaying horological information. Watch component (1) according to one of the preceding claims, characterized:

- in that the substrate (1 1) comprises a first surface (1 1 1) and a second surface (1 12), in particular a second surface (1 12) parallel or substantially parallel to a first surface (11 1),

- in that the first layer (12) and/or the second layer (13) are applied to the first surface (1 1 1), and

- in that the first surface (1 1 1), in particular the first layer and/or the second layer applied to the first surface, is visible through the second surface (1 12) and the substrate (1 1). Watch component (1) according to claim 6, characterized in that the substrate (1 1) comprises at least one second recess (15) made on the second surface (1 12), in particular at least one second recess (15) made by laser machining. Watch component (1) according to the preceding claim, characterized in that the at least one second recess (15) is coated, in particular coated with a metal-based layer, in particular coated with a metal-based layer deposited by PVD , CVD, ALD or PLD. Watch component (1) according to one of claims 6 to 8, characterized in that the substrate (1 1) has an anti-reflective treatment on the second surface (1 12). Watch component (1) according to one of the preceding claims and according to claim 6, characterized in that the substrate (1 1) comprises at least a first recess (14) made on the first surface (1 1 1) after application of the first and second layers, in particular at least one first recess (14) produced by laser machining. Watch component (1) according to the preceding claim, characterized in that the at least one first recess (14) is coated, in particular coated with a metal-based layer, in particular coated with a metal-based layer deposited by PVD , CVD, ALD or PLD. Watch component (1) according to claim 10 or 1 1, characterized in that the at least one first recess (14) is such that the area of material ablated at the level of a plane perpendicular to a direction in which the at least one first hollowing is made, arranged between:

- a surface defining the bottom of the at least one first hollow, is scalable according to the direction in which the at least one first hollow is made, and/or is such that the area of material ablated at the level of a plane any parallel to the direction in which the at least one first recess is made is progressive in a direction orthonormal to the direction in which the at least one first recess is made. Watch component (1) according to one of claims 10 to 12, characterized in that the at least one first recess (14) has a millimetric or micrometric or nanometric area, in particular at the level of a surface defining the bottom of the hollowing and/or at the level of the surface from which it is carried out. Process for producing a watch component (1), the process comprising the following steps:

- supply of a substrate (1 1) made of at least partially transparent material,

- application of a first layer of colored enamel (12) on the substrate (11), in particular application of the first layer of colored enamel (12) on the substrate (1 1) by transfer, in particular by decal of a chromo on the substrate (1 1), and

- application of a second layer (13) of finishing, in particular of a second layer (13) of opacifying finishing at least partly on the first layer of colored enamel (12). Production method according to the preceding claim, characterized in that the application of the second layer is:

- application of a layer of another coating, such as paint. Production method according to one of claims 14 and 15, characterized in that it comprises a step of producing at least one first recess (14) on a first surface (1 1 1) of the substrate (1 1), in particular at least one first recess (14) produced by laser machining, and/or in that it comprises a step of producing at least one second recess (15) on a second surface (1 12) of the substrate (1 1 ), in particular at least a second recess (15) produced by laser machining. Production method according to claim 16, characterized in that the step of producing at least one first hollowing and/or the step of producing at least one second hollowing are carried out after the step of applying the first layer of enamel (12) on the substrate (1 1), and in that, in the step of producing at least one first hollow and/or the step of producing at least a second recess, a decoration formed by the first layer of enamel is used as a reference, in particular as a machining reference. Production method according to one of claims 16 and 17, characterized in that the method comprises a step of coating the at least one first recess (14) and/or the at least one second recess (15), in particular by a metal-based layer, in particular by a metal-based layer deposited by PVD, CVD, ALD or PLD. Timepiece (100) comprising a watch component (1) according to one of claims 1 to 13, in particular a watch component (1) according to one of claims 6 to 13 arranged so that the first surface (1 1 1), in particular the first layer (12) and/or the second layer (13), is visible through the second surface (112) and the substrate (1 1) by the wearer of the timepiece ( 100).