CH715191B1 - Process for decorating a watch exterior component. - Google Patents

Abstract

The present invention relates to a process for decorating, with a filler material (5) according to a predefined pattern, a watch or jewelery trim component comprising a substrate (1), the process comprising the following steps: a . depositing at least one sacrificial layer (2,3) on the substrate (1); b. etching hollows (4) in the substrate (1) according to the predefined pattern through said sacrificial layer (2,3); vs. depositing the filler material (5) on said substrate (1) and the sacrificial layer (2,3); d. removing said sacrificial layer (2,3) by means of selective etching.

Description

Object of the invention

[0001] The present invention relates to a process for decorating a watch or jewelry trim component.

Technology background

The present invention aims to improve the processes for depositing decorative patterns on the surface of a timepiece component. In particular, the present invention aims to provide a method for depositing a decoration obtained by deposition of a thin layer of the PVD type (Physical Vapor Deposition, or physical deposition in the vapor phase) according to a delimited pattern whose surface state is different from that of the component. For example, a polished black ceramic bezel with a matt minute track on which a gray PVD layer is deposited.

According to the prior art, this type of decorative deposit is obtained by a PVD deposit followed by removal of the PVD layer by a mechanical process outside the matte areas. This technique requires a significant difference in height between the two surface states to avoid damaging the layer in the matte part during the mechanical removal operation of the layer in the polished area, the tool being able to come into contact with the matte area. .

[0004] Alternatively, it is possible to structure the PVD layer using a mask or a selective polymerization technology aligned with the matte area. However, it is difficult to achieve perfect alignment of the mask with the matte area. This technique generally leaves a matte area not covered by the PVD layer.

Summary of the invention

[0005] The present invention relates to a process for decorating, by filler material according to a predefined pattern, a watchmaking or jewelery trim component comprising a substrate, the process comprising the following steps: a. depositing at least one sacrificial layer on the substrate; b. etching recesses in the substrate according to the predefined pattern through said sacrificial layer; vs. depositing the filler material on the sacrificial layer or on an additional layer covering the sacrificial layer; d. removing said sacrificial layer by selective etching.

[0006] Preferably, a photoresist mask having holes aligned with the recesses is added after the etching of the sacrificial layer and before the deposition of the filler material. Advantageously, the holes aligned with the recesses are of dimensions slightly greater than the dimensions of the recesses.

[0007] Advantageously, the substrate is made of a material that is not very ductile. It can, for example, be a ceramic, sapphire, ruby, etc. Preferably, it is a ceramic and, more preferably, a zirconia.

[0008] Preferably, the sacrificial layer comprises a metallic layer, preferably gold.

[0009] Advantageously, the sacrificial layer comprises an adhesive layer preferably comprising titanium.

Preferably, the selective chemical attack is a liquid attack, said liquid advantageously comprising aqua regia, cyanide, lodide and/or hydrofluoric acid.

[0011] Preferably, the etching of the recesses is carried out by a laser etching process making it possible to etch the sacrificial layer and the substrate.

[0012] Advantageously, the deposition of the filler material is an anisotropic vapor phase deposition (PVD, vacuum evaporation, pulsed laser ablation).

[0013] Preferably, the substrate is polished before the deposition of the sacrificial layer.

Advantageously, the filler material is selected from the group consisting of CrN, ZrO2, Cr, Ti, Au, ZrN.

[0015] In cases where the filler material is gold or titanium, the material of the sacrificial layer must be adapted to allow selective etching.

Brief description of figures

• Figures 1a to 1e show the successive steps of a preferred example of a decoration process according to the invention. • Figure 2 shows a trim component, and, in particular, a watch bezel decorated with the method according to the invention. • Figures 3d to 3g represent steps of a preferred embodiment of the method of the invention.

Detailed description of the invention

[0017] The present invention proposes a process for depositing a decorative pattern on a watch or jewelry trim component by physical vapor deposition (PVD). The covering component 6 can in particular be a bezel, a dial, a case, a crown, a pusher, a crystal, a bracelet element, etc. By way of example illustrated in FIG. 2, component 6 is a watch bezel comprising an annular body constituting substrate 1 decorated with indices forming decorative pattern 5.

The method of the invention comprises a first step in which a sacrificial layer 2.3 is deposited on the substrate 1 of the watch component, as shown in Figure 1b. This sacrificial layer 2.3 is intended to be removed by selective chemical attack during a subsequent step. It is therefore selected so as to be able to be chemically removed without degrading the substrate or the deposit. In particular, the selective etching of the sacrificial layer must not modify the surface condition of the areas on which the PVD deposit is not made. According to a preferred mode of the invention, the substrate is polished zirconia. In this case, the sacrificial layer is advantageously a continuous gold layer 3, for example deposited by vacuum evaporation. The selective chemical attack is then advantageously carried out by a stripper based on cyanide. The thickness of this layer must be sufficient to allow attack by the edge of the layer. This layer will therefore preferably have a thickness of between 50 and 250 nm.

To improve the mechanical stability of the interface between the sacrificial layer 3 and the substrate 1, an adhesive intermediate layer 2 is advantageously deposited before the sacrificial layer 3 itself. Titanium generally exhibits adequate adhesion to most common substrates. The titanium layer can be removed by etching with hydrofluoric acid. The thickness of this layer can be extremely low: a few nm are generally sufficient to considerably improve adhesion. A very small thickness has the advantage of reducing the etching time enabling this layer to be removed. Substrate 1 covered with sacrificial layer 2.3 is then etched according to the desired pattern. After this step, a substrate 1 is therefore obtained comprising recesses 4 arranged according to the desired pattern. These recesses 4 pass through the sacrificial layers and extend into the substrate as shown in FIG. 1c. The depth of these recesses 4 in the substrate 1 is preferably at least equal to the thickness of the PVD deposit 5 envisaged. The etching process must be both directional and not very selective since it must etch both the substrate 1 and the sacrificial layer(s) 2.3.

Advantageously, the engraving of the recesses 4 is carried out by a laser process which makes it possible to easily control the engraved pattern, to make recesses 4 having walls essentially perpendicular to the surface of the substrate 1, to quickly engrave numerous parts, and finally, to finely check the surface condition of the engraved area. Alternatively, an ion beam can also be used, although more complex to use.

Then, during a PVD deposition step shown in Figure 1d, a filler material 5 is deposited over the entire surface of the component to be decorated. The thickness of the deposited layer is typically of the order of 0.1 to 2 μm. The thickness of the filler layer 5 is essentially constant. Advantageously, the deposition is a directional deposition, leaving the walls of the hollows 4 free above the deposited layer. For example, the deposition can be carried out by evaporation under vacuum, by cathode sputtering of a cathode of suitable composition or even by ablation of a target by a pulsed laser.

[0022] The decorative layer is, for example, a matte material presenting a high contrast with the substrate. For example, it may be a matte gray chromium nitride deposit on a polished black zirconia substrate. Advantageously, the deposition of the decorative layer 5 leaves the edge of the sacrificial layer free.

In the next step, shown in Figure 1e, a selective chemical attack removes the sacrificial layer(s) 2.3, uncovering the free areas outside the recesses 4. Indeed, the removal of the sacrificial layer under the deposit 5 eliminates the adhesion of the latter to the substrate outside the recesses 4.

In the example mentioned in which the filler material is CrN deposited on a black zirconia substrate, an adequate sacrificial layer is a titanium/gold bilayer, with a titanium thickness of the order of 1 to 50 nm. and a gold layer with a thickness of between 50 and 200 nm, the attack on the Au layer being carried out using a cyanide-based stripper. If necessary, an attack with hydrofluoric acid makes it possible to remove the Ti residues. Other possible combinations include, for example, zirconias of different colors, for example polished black zirconia for the substrate and matt white zirconia for the decorative deposit.

As shown in Figures 3d to 3g, to reduce edge effects, it may be useful to add a mask 8 of photoresist 7 before depositing filler material 5. This photoresist 7 is first deposited in a continuous layer as shown in Figure 3d. It is then irradiated (generally not UV) according to a pattern corresponding to that of the hollows 4. Depending on whether it is a positive or negative resin, the irradiated or non-irradiated parts are then dissolved, again revealing the hollows 4. Advantageously, the pattern of the mask 8 reveals a narrow margin 9 at the edge of the hollows as represented in FIG. 3e. The filler material is then deposited in a layer of constant thickness (FIG. 3f) as in the absence of a mask. Finally, the mask 8 is dissolved, revealing the sacrificial layer 3 (FIG. 3g). The process then resumes as in the absence of a mask.

Reference numbers for figures

[0026] 1 substrate 2 adhesive layer 3 sacrificial layer 4 hollow 5 decorative pattern or filler material 6 covering component 7 photoresist 8 mask

Claims (13)

1. Method of decorating with a filler material (5) according to a predefined pattern of a watchmaking or jewelery trim component comprising a substrate (1), the method comprising the following steps: at. depositing at least one sacrificial layer (2,3) on the substrate (1); b. etching hollows (4) in the substrate (1) according to the predefined pattern through said sacrificial layer (2,3); vs. depositing the filler material (5) on the substrate (1) and the sacrificial layer (2,3); d. removing said sacrificial layer (2,3) by means of selective etching. 2. Method according to claim 1, in which the substrate (1) is made of a material chosen from ceramic, sapphire, ruby, steel, titanium, gold alloys, platinoid alloys and mixtures thereof. . 3. Method according to claim 1 or 2, wherein the substrate (1) is made of a zirconia-based ceramic. 4. Method according to one of the preceding claims, wherein the sacrificial layer (2,3) comprises a metal layer, preferably gold. 5. Method according to claim 4, in which the selective chemical attack is a liquid attack. 6. A method according to claim 5, wherein said liquid comprises aqua regia, cyanide, iodide and/or hydrofluoric acid. 7. Method according to one of the preceding claims, in which the sacrificial layer (2,3) comprises an adhesive layer (2) preferably comprising titanium. 8. Method according to one of claims 1 or 2, wherein the filler material (5) is selected from the group consisting of CrN, ZrO2, Cr, Au, Ti, ZrN and mixtures thereof. 9. Method according to one of the preceding claims, in which the etching of the recesses (4) is carried out by a laser etching process making it possible to etch the sacrificial layer (2,3) and the substrate (1). 10. Method according to any one of the preceding claims, in which the deposition of the filler material (5) is an anisotropic vapor phase deposition. 11. Method according to one of the preceding claims, in which the substrate (1) is polished before the deposition of the sacrificial layer (2,3). 12. Method according to one of the preceding claims, in which a mask (8) of photoresist (7) having holes aligned with the recesses (4) is added after the etching of the sacrificial layer (2,3) and before the deposition filler material (5). 13. The method of claim 12 wherein the holes aligned with the recesses are of dimensions slightly greater than the dimensions of the recesses.