Method for Decorating Watch Parts

Abstract

To impart different visual appearances to watch parts. 【Solution means】The present invention relates to a method for decorating the dial of a watch part (30), particularly a skeleton type watch. This part (30) has at least two different visual appearances, and each visual appearance is a unique combination of surface finish and color. The decoration method includes: i) providing a part blank (10) with a first unfinished surface (10a); ii) applying a first end (12) with a first surface finish on the first unfinished surface (10a); iii) applying one or more atomic layers to the first end (12) to give the first end (12) a first color (14); iv) making at least one angular break in the blank to form at least one beveled part or at least one chamfered part (18) with a second unfinished surface; v) applying a second end (20) with a second surface finish to the second unfinished surface (18a); vi) depositing a metal layer of preferably rhodium or gold on the second end (20) using electroplating, PVD, or ALD to give the second end (20) a second color (22).

Description

Technical Field

[0001] The present invention generally relates to a method for decorating parts with multiple surface treatments. This method is particularly suitable for decorating skeleton type dials. The present invention also relates to one or more watch parts obtained according to the method for decorating parts, in particular a timepiece comprising a skeleton type dial, a movement plate, one or more bridges and one or both of the oscillators.

Background Art

[0002] It is known to decorate the surface of watch parts such as dials, movement bridges or sheet metal to give an interesting visual appearance. In particular, the surface of the part is processed by traditional processes such as brushing, circular graining, satin finish, sandblasting to give a specific structure. Such an approach includes a single step of machining the surface to be decorated to obtain the desired visual effect. This step can be combined with other steps to apply a thin colored layer, for example using PVD or electroplating processes.

[0003] For example, Patent Document 1 discloses a decorative treatment comprising a watch part, the treatment comprising the steps of preparing the watch part, a corrosion prevention step, and a coloring step of forming an external decorative color layer. Patent Document 2 discloses, among other things, a process for producing a decorative coating having a white colored surface obtained by superimposing layers deposited using electroplating and CVD processes.

[0004] The decorative possibilities provided by these processes are limited to choosing from a limited number of well-known solutions and cannot provide unique decorative solutions.

[0005] Furthermore, known decorative treatments must meet high quality standards so that the decorated parts can withstand loads such as impacts and accelerations that are particularly common in sports watches. For this reason, the number of steps in known processes has been reduced in order to keep manufacturing costs down.

[0006] Patent Document 3 discloses a method for manufacturing watch parts that can be subjected to various changes from both a technical and an aesthetic point of view. In particular, in the manufacturing process, the watch part is machined to form a substantially flat dial surface and at least one side surface adjacent to the substantially flat dial surface. A chamfered portion is then machined at the joint between the substantially flat dial surface and the side surface, and subsequently, a coating is directly applied to the rough surface of the chamfered portion.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0008] An object of the present invention is to provide a method for decorating watch parts, by which it is possible to impart a wide variety of different visual appearances to the parts.

[0009] Another object of the present invention is to provide a decorative method for enhancing the visual quality of parts, particularly of the dial of a watch, especially of the skeleton type.

[0010] A further object of the present invention is to provide parts, particularly the dial of a watch, especially of the skeleton type, especially of a sports watch, that can withstand the loads that the watch will be subjected to.

Means for Solving the Problem

[0011] These objects are particularly achieved by a method of decorating a watch part having at least two different visual appearances. Each visual appearance is a unique combination of surface finish and color. The decoration method is as follows i) providing a part blank having a first unfinished surface; ii) applying a first finish with a first surface finish on the first unfinished surface; iii) applying one or more atomic layers to the first finish to give the first finish a first color; iv) making at least one angular break in the blank to form at least one beveled portion or at least one chamfered portion having a second unfinished surface; v) applying a second finish with a second surface finish on the second unfinished surface; vi) depositing a layer of preferably rhodium or gold on the second finish using electroplating, PVD (Physical Vapor Deposition), or ALD (Atomic Layer Deposition) to give the second finish a second color and comprising.

[0012] In one embodiment, the decoration method further comprises applying a sacrificial protection layer to the first color between step iii) and step iv). This sacrificial protection layer is removed after step vi).

[0013] In one embodiment, the part is selected from a bridge, a plate, a balance, a dial having one or more windows, and a skeleton type dial. The dial may also be provided with graduations.

[0014] In one embodiment, the watch part is made of a copper alloy such as steel like white brass, 316L steel (low-carbon, austenitic stainless steel), Durnico® (a kind of low-carbon martensitic steel), ceramic, or a precious metal such as gold, platinum, palladium, etc.

[0015] In one embodiment, the first finish is obtained by sandblasting, bead blasting, straight or circular or spiral satin finish, azuré finish, manual or mechanical gilding, the giochè method, the circular grain method, the coated Geneva method, hand carving, or polishing.

[0016] According to one embodiment, the second finish is obtained by straight satin finish, flat finish, manual bevelling, manual engraving or sandblasting.

[0017] According to one embodiment, step iii) includes performing PVD, ALD or electroplating treatment on the first end.

[0018] As another aspect of the invention, it relates to watch parts, in particular bridges, plates, oscillators, dials with one or more windows or skeleton type dials, obtained by the decoration method according to the invention.

[0019] According to one embodiment, the component is the dial of a skeleton type watch. The dial comprises a dial part and a transparency part defined by the contour of the dial part. The dial part preferably comprises a plane extending on the surface of the dial and a bevelled part arranged around the transparency part. The dial part has a first appearance and is provided with a first finish and a first color. The bevelled part of the dial has a second appearance different from the first appearance and is provided with a second finish and a second color.

[0020] The invention also relates to a timepiece comprising a part obtained by the method according to the invention, in particular the above-mentioned skeleton type dial.

[0021] An example of an embodiment of the invention is illustrated in the accompanying drawings.

Brief Description of the Drawings

[0022]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0023] In a preferred embodiment exemplified by Steps 1a to 1g, this method comprises a first step of performing a first decoration operation on the unfinished surface 10a of the blank 10 of the watch part to obtain the first terminal 12 in FIG. 1b.

[0024] In the case of the skeleton type dial shown in FIG. 2, the method comprises a step of applying a watermark portion 32 to a dial blank which is a solid disk-shaped member having an unprocessed surface, prior to the decoration operation. This operation is preferably carried out by a wire cut electrical discharge machining (EDM) process.

[0025] The part blank 10, particularly the dial blank, is preferably made of a copper alloy, particularly brass, which can withstand mechanical stress, particularly the acceleration to which a sports watch is subjected.

[0026] The first terminal 12 is applied to the unprocessed surface of the dial portion surrounding the various watermark portions. These unprocessed surfaces are preferably flat and typically extend on the surface of the skeleton dial.

[0027] The first terminal 12 can be obtained by various decoration techniques. Such decoration methods include, in particular, sandblasting to obtain a certain degree of roughness, or satin finishing by coating the raw surface 10a of the blank 10 with a set of very thin parallel stripe patterns (e.g., straight, circular, or helical stripes) to capture light from various angles. Other techniques (in particular, bead blasting (processing), gyosha (engraving), circular grain (pattern of closely spaced circles), côte de Genève (finished with multiple parallel lines), manual or mechanical gilding, hand carving, polishing, azuré finish (decoration method with concentric circle patterns)) can be used to process and structure the raw surface 10a of the blank 10 to give it a unique visual appearance.

[0028] Blanks made of other materials (in particular, precious metals such as steel (e.g., type 316L low-carbon steel), gold, platinum, palladium, or ceramics or titanium to avoid corrosion) can also be used.

[0029] Once the first terminal 12 is completed, it is subjected to PVD (physical vapor deposition) treatment, and a thin film 14 of a desired color (in particular, black) is deposited under vacuum (Figure 1c). To obtain the film 14, ALD (atomic layer deposition) treatment or electroplating treatment may be performed instead of PVD treatment. Then, a sacrificial protective layer 16 (Figure 1d) is applied to the entire dial. This protective layer can be, for example, an epoxy varnish for protecting the film 14 from particles generated in subsequent steps of the decoration method described later.

[0030] In FIGS. 1e and 2, then, machining of the skeleton type dial is performed to cut the angle of the contour of the transparent portion 32 of the dial, and a bevel portion 18 (an inclined edge between two surfaces) or a chamfer portion 18 (a 45-degree cut with respect to two adjacent surfaces) is obtained to expose the base material (for example, silver) that particularly constituted the blank. These bevel or chamfer portions define the periphery of the transparent portion 32 of the dial. Then a second terminal 20 is applied to the raw surface 18a of the chamfer portion or chamfer portion 18 (FIG. 1f). Similar to the first terminal 12, the second terminal 20 is obtained by various decorative techniques, particularly sandblasting, linear satin finish, for example, a flat finish applied using a diamond point, manual chamfering, or manual engraving.

[0031] When the second terminal 20 is manufactured, a contouring operation is generally performed to give the final shape to the dial.

[0032] Referring to FIG. 1g, following this contour forming step, an electroplating step is performed on this second terminal 20 to deposit a metal film 22 of a desired color. This metal film is, for example, a rhodium, gold, NAC, or black NAC film, and black NAC is a deep smokeless coal-colored black coating.

[0033] Then, to remove the epoxy varnish protective layer 16, a solvent is applied to the entire dial to perform a varnish removal operation. Then, a transfer operation is performed to create the dial, particularly the markings of the dial.

[0034] The decoration method can also be applied to watch parts made of aluminum or aluminum alloy and watch parts made of titanium or titanium alloy. For this type of material, the anodizing process is used to give the first color and the second color to the first terminal and the second terminal, respectively.

[0035] The above description mainly refers to the decoration method applicable to the skeleton type dial, but this method is preferably applicable to other watch parts with a main surface, which is preferably flat, and one or more beveled or chamfered parts. Therefore, this method is particularly applicable to bridges, watch movement plates, and oscillators of automatic winding movements, or to dials with graduations and (one or both of one or more beveled or chamfered parts).

[0036] Furthermore, in a modification of an embodiment, the coloring of the first terminal 12 and the second terminal 20 can be performed in the same way. For example, both the first terminal 12 and the second terminal 20 can be subjected to PVD treatment, ALD treatment, or galvanic (melt plating) treatment. However, it is necessary to note that the variables of these treatments are different between the first terminal 12 and the second terminal 20.

[0037] The dial 30 of FIG. 2 thus has two different visual appearances, and each visual appearance is a unique combination of surface finish and color.

Claims

**Claim 1** A method of decorating a timepiece part (30) having at least two different visual appearances, each visual appearance being a unique combination of surface finish and color, the method comprising: i) providing a part blank (10) having a first unfinished surface (10a); ii) applying a first finish (12) having a first surface finish on the first unfinished surface (10a); iii) applying one or more atomic layers to the first finish (12) to impart a first color (14) to the first finish (12); iv) making at least one angular break in the blank to form at least one beveled portion or at least one chamfered portion (18) having a second unfinished surface (18a); v) applying a second finish (20) having a second surface finish on the second unfinished surface (18a); vi) depositing a metal layer of preferably rhodium or gold on the second finish (20) using electroplating, PVD, or ALD to impart a second color (22) to the second finish (20). A method of decorating a timepiece part (30). **Claim 2** The method of decoration according to claim 1, further comprising applying a sacrificial protection layer (16) to the first color (14) between step iii) and step iv), the sacrificial protection layer (16) being removed after step vi). **Claim 3** The method of decoration according to claim 1 or 2, wherein the timepiece part is selected from a bridge, a plate, a balance, a dial having one or more windows, and a skeleton type dial. **Claim 4** The method of decoration according to any one of claims 1 to 3, wherein the timepiece part is made of steel, gold, platinum, palladium, ceramic, or a copper alloy, particularly nickel silver. **Claim 5** The method of decoration according to any one of claims 1 to 4, wherein the first finish (12) is obtained by sandblasting, bead blasting, straight or circular or spiral satin finish, azuré finish, hand or machine forging, guilloché method, circular grain method, côte de Genève method, hand carving, or polishing. **Claim 6** The method of decoration according to any one of claims 1 to 5, wherein the second finish (20) is obtained by straight satin finish, flat finish, hand beveling, hand carving, or sandblasting. **Claim 7** The decorative method according to any one of claims 1 to 6, wherein step iii) comprises performing PVD, ALD or galvanic treatment on the first terminal (12). **Claim 8** A watch part obtained by the decorative method according to claims 1 to 7, in particular a bridge, a plate, a resonator, a dial with one or more windows or a skeleton type dial. **Claim 9** The watch part is a dial (30) of a skeleton type watch, and the dial comprises a dial part and a transparency part defined by the contour of the dial part. The dial part comprises a surface and a beveled part or a chamfered part arranged adjacent to the surface of the dial part and around the transparency part. The surface comprises the first terminal and the first color so as to give a first appearance. The watch part according to claim 8, wherein the beveled part or the chamfered part comprises the second terminal and the second color so as to give a second appearance different from the first appearance. **Claim 10** A timepiece comprising the watch part according to claim 8 or 9.

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