Methods for decorating watch parts

Abstract

To provide a method for decorating watch components. [Solution] The present invention relates to a method for decorating watch parts using white plating. The method comprises preparing the watch parts; depositing a metal adhesive layer over the watch parts in a deposition chamber by physical vapor deposition; depositing an aluminum diffusion layer over the parts by physical vapor deposition while flowing a reagent gas, so that the aluminum layer is deposited to a desired thickness in the form of a faceted crystal structure; depositing a hard layer on the aluminum layer by physical vapor deposition to mechanically protect the aluminum layer but maintain the faceted structure; depositing a thin, highly reflective metal layer on this hard layer by physical vapor deposition; and finally, depositing a transparent layer on this reflective layer for protection and / or increased reflectivity using ALD.

Description

Technical Field

[0001] The present invention relates to a plating having a white surface obtained by superimposing layers deposited by PVD and ALD. The present invention also relates to a watch part having such a white surface.

Background Art

[0002] The watch industry is constantly seeking new solutions regarding color and appearance. White watch parts such as dials are often made using mother-of-pearl or by applying enamel.

[0003] The surfaces of noble metals such as silver, platinum, palladium, and rhodium give a shiny appearance. Such an appearance can also be achieved by electroplating these metals. However, since these metals specularly reflect light, they give a shiny metallic gloss to the surface of the part. By appropriately setting the parameters of the electroplating method, the specular reflection of this plating can be reduced and a matte white appearance can be achieved.

[0004] Physical vapor deposition (PVD) techniques such as cathodic sputtering can be used to deposit thin plating with predetermined characteristics on substrates of various complex (three-dimensional) shapes.

[0005] There are also several white natural substances. Examples include pigments composed of fine particles of minerals such as titanium oxide or aluminum oxide. These particles diffusely reflect light. These pigments are deposited on the surface of the part in the form of paint, lacquer, or enamel.

[0006] However, pigment-based white plating cannot achieve sufficient and satisfactory decorative quality. In fact, neither the surface finish of the substrate nor the details of the decoration can be maintained. Furthermore, the electroplating used in the prior art has a matte appearance and is relatively brittle.

[0007] Therefore, white plating is required to maintain the surface finish and decorative details of the substrate. [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] The present invention aims to improve, in particular, various drawbacks of methods used in the prior art.

[0009] More specifically, one object of the present invention is to provide a method for producing a “porcelain” white plating that maintains the surface finish of a polished, matte, sunburst, or any other decorative substrate, as well as a watch component having a surface plated with a thin white layer obtained by this method. [Means for solving the problem]

[0010] For this purpose, the present invention involves the following steps, namely, - The steps of preparing the clock components and placing the components in the deposition chamber, - A step of depositing a metal adhesive layer over the entire watch component using physical vapor deposition, - Using physical vapor deposition, an aluminum diffusion layer is deposited over the entire component while a reagent gas is flowed through it. The deposited layer contains 0.5 to 10 atomic percent of this gas, and the aluminum layer crystallizes in the form of a faceted crystal structure. - A step of depositing a hard layer on top of the diffusion layer to enhance the diffusion layer's resistance to scratches and mechanical damage while maintaining the structure of the diffusion layer, - A step of depositing a pure metal layer to increase the reflectivity of the already deposited layer, - A step of depositing a transparent layer using ALD or another vacuum deposition method to improve the white appearance through interference effects and to chemically protect the layer deposited in the previous step, - Or, a method for decorating watch components with white plating, comprising the step of depositing a transparent protective layer using the ALD method or another vacuum deposition method.

[0011] According to other advantageous modifications of the present invention, - The adhesive layer is a metal layer or a metal alloy layer which can be selected from aluminum, titanium, titanium aluminide, nickel, or chromium. - The adhesive layer has a minimum thickness of 5 nm. - The diffusion layer has a thickness of 300 nm to 6,000 nm, preferably 1,000 nm to 2,000 nm, preferably 1,500 nm. - The hard layer has a thickness of 100 nm to 3,000 nm, preferably 400 nm to 2,000 nm, preferably 1,000 nm. - The hard layer is made of DLC, nitrides or carbonitrides, oxynitrides, or a material selected from titanium oxide, titanium aluminum oxide, silicon oxide, aluminum oxide, nickel oxide, or chromium oxide. - The final layer of pure metal has a thickness of 20 nm to 400 nm, preferably 200 nm. - The pure metal layer is made of a highly reflective metal selected from aluminum, silver, rhodium, or chromium. - The transparent layer is coated with a transparent dielectric layer. - The transparent dielectric layer has a refractive index of 1.38 to 2.6 at a wavelength of 633 nm and a thickness of 5 nm to 500 nm. - The transparent protective layer has a thickness of 0.5 nm to 20 nm, preferably 2 nm. - The transparent protective layer can be selected from the following materials, namely titanium dioxide, aluminum oxide, silicon dioxide, silicon nitride, or other transparent materials that can withstand the typical environment during the product's service life. - The step of preparing the watch components before depositing the aforementioned layers comprises a cleaning step, - The watch components have the desired decoration and / or the desired surface finish. - The reagent gas used when depositing the permeable layer is oxygen, nitrogen, or a mixture of both.

[0012] The present invention also relates to watch components having a white plating obtained using the method according to the present invention.

Advantages of the Invention

[0013] Other features and advantages of the present invention will become apparent from the following detailed description given by way of non-limiting examples while referring to the accompanying drawings.

Brief Description of the Drawings

[0014] [Figure 1] FIG. 1 schematically shows a substrate having a white plating obtained by the method of the present invention. [Figure 2] FIG. 2 schematically shows the steps of the method according to the present invention.

Modes for Carrying Out the Invention

[0015] FIG. 1 is a schematic view of the coating of the layer obtained by the method of the present invention.

[0016] According to one aspect of the present invention, the deposition of plating for imparting white color to the surface of a decorative part is performed by a series of PVD depositions and ALD depositions.

[0017] Preferably, for the purposes of the present invention, a chamber equipped with a magnetron sputtering system is used. The sputtering system includes, inside the chamber, at least one aluminum sputtering target and a gas injection line for creating a controlled reagent atmosphere or an inert atmosphere. The function of this sputtering device has been described in scientific and technical literature and is known to those skilled in the art, so only a general overview is provided herein.

[0018] The method according to the present invention, in this case where the substrate is a clock part, comprises a first step 20 in which the substrate is cleaned at a predetermined position within the deposition system by plasma polarization of the substrate holder or by any other method known to those skilled in the art.

[0019] The method comprises a second step 21 of depositing a first layer 10, known as an adhesive layer, onto a substrate 1. The adhesive layer 10 can be made of aluminum deposited by sputtering from an aluminum source in a neutral atmosphere, i.e., without the addition of reagent gases. The adhesive layer can also be made of titanium, titanium aluminide, or chromium, and typically has a thickness of 30 nm to 100 nm, preferably 50 nm.

[0020] The third step 22 comprises depositing the second layer 11. In this step, a reagent gas, such as oxygen, nitrogen, or a mixture of both, is introduced into the chamber using a cathode equipped with an aluminum target, and the reagent gas is doped at a rate of 0.5 to 10 atomic percent, producing an aluminum layer referred to as the diffusion layer 11. The diffusion layer 11 has a thickness of 300 nm to 6,000 nm, preferably 1,000 nm to 2,000 nm, and preferably 1,500 nm.

[0021] The objective of this third step is to influence the deposition of aluminum atoms using a reagent gas to obtain a layer of aluminum oxide (aluminum nitride in the case of nitrogen, or aluminum oxynitride in the case of a mixture of nitrogen and oxygen) having a faceted crystalline structure. Such a layer, due to its faceted crystalline structure, allows for the acquisition of a diffusion effect of incident light.

[0022] The fourth step 23 comprises depositing a hard layer 12 on the diffusion layer 11, the hard layer 12 being selected from hard materials known to those skilled in the art, such as DLC, nitrides or carbonitrides, titanium oxide, titanium aluminum oxide, silicon oxide, aluminum oxide, or chromium oxide.

[0023] The function of this hard layer 12 is to protect the brittle aluminum diffusion layer, which is susceptible to scratches and mechanical damage. Furthermore, in order to maintain the diffuse appearance of the watch components, the hard layer 12 must match the structure of the diffusion layer. The hard layer 12 has a thickness of 200 nm to 3,000 nm, preferably 400 nm to 2,000 nm, and preferably 1,000 nm.

[0024] In step 5, step 24, a pure metal layer 13 is deposited on the hard layer 12. This pure metal layer 13 is used to mask the color of the hard layer 12 and give the watch component a diffuse white appearance. The final pure metal layer 13 has a thickness of 20 nm to 400 nm, preferably 200 nm.

[0025] The pure metal layer 13 is made of a highly reflective metal selected from aluminum, silver, rhodium, or chromium.

[0026] In order to further increase the reflectivity of the watch components and thereby enhance their "white" appearance, a transparent layer 14, referred to as a "booster" layer, is deposited in step 6, step 25.

[0027] This transparent layer 14 is composed of a thin film dielectric coating of transparent material, and its refractive index and thickness are such that, as a result of interference effects, the watch component's L in the 1976 CIE color space. * The value is selected to increase compared to the value without coating, but the hue (a * ,b * The following characteristics are maintained: For example, the refractive index is in the range of 1.38 (equivalent to MgF2) to 2.6 (equivalent to TiO2) at a wavelength of 633 nm, and the thickness is in the range of 5 nm to 500 nm.

[0028] This transparent layer 14 protects the already deposited layer from corrosion caused by the environment commonly encountered throughout the lifespan of the watch. This layer 14 can be omitted if it is not necessary (for example, if the "white" effect is sufficient without it).

[0029] Finally, in step 7, step 26, a sixth transparent protective layer 15 is deposited, preferably using ALD deposition. The protective layer 15 is made of one of the following materials: titanium dioxide, aluminum oxide, silicon dioxide, or silicon nitride. This step is necessary if step 25 is omitted, or if the coating at this point in time does not adequately protect these layers. The diffusion layer 11 thus covered with the pure metal layer 13 effectively reflects diffuse white light, imparting whiteness to the treated substrate and maintaining its surface finish and decorative details.

[0030] A first exemplary embodiment of the method according to the present invention. - Substrate 1 is cleaned at a predetermined position in the deposition chamber by plasma polarization of the substrate holder. - An aluminum adhesive layer is deposited using an aluminum target without the addition of reagent gas. - Subsequently, without turning off the cathode, oxygen is introduced into the deposition chamber, and the oxygen flow is selected and controlled so that a 1,600 nm aluminum layer with an oxygen content of 0.5 to 10 atomic percent is deposited in a diffusion crystalline structure. - Subsequently, without turning off the cathode, the oxygen flow was increased and maintained at a value that yielded a hard 1,000 nm layer with a composition close to Al2O3. Next, without turning off the cathode, the oxygen flow is completely stopped, and the coating deposition is finished with a 100 nm thin film of pure aluminum without oxygen doping, thereby imparting a diffuse white appearance to the coating. - Once a pure aluminum film of the desired thickness is achieved, the PVD deposition process is complete, and a transparent "booster" layer and / or protective layer is deposited using the ALD deposition method.

[0031] A second exemplary embodiment of the method according to the present invention. - Substrate 1 is cleaned at a predetermined position in the deposition chamber by plasma polarization of the substrate holder. - Without adding reagent gas, an aluminum adhesive layer is deposited using an aluminum target. - Subsequently, without turning off the cathode, nitrogen is introduced into the deposition chamber, and the nitrogen flow is selected and controlled so that an 800 nm layer of aluminum with a nitrogen content of 0.5 to 10 atomic percent is deposited in a diffusion crystalline structure. - Once a doped nitrogen layer of the desired thickness is achieved, a 1,000 nm thick hard TiN layer is deposited on the nitrogen-doped aluminum layer. - Subsequently, a thin film of pure aluminum with a thickness of 160 nm is deposited, giving the coating a diffuse white appearance. - Once a pure aluminum film of the desired thickness is achieved, the PVD deposition method is terminated, and a transparent "booster" is deposited using the ALD deposition method. This coating consists of 30nm-90nm aluminum oxide and 20nm-100nm titanium oxide, and its function is to further increase the reflectivity of the pure aluminum layer, which in turn improves the diffuse white appearance of the coating.

[0032] The substrate, i.e., the watch component, has a polished, structured, or decorated surface, such as engraved, circular wood grain, satin finish, Côtes de Genève pattern, snail pattern, rose engine turn, sunburst, or engraved finish. The white decorative plating of the present invention is thin enough that the decoration is clearly visible and reflects the surface finish of the underlying substrate. This results in a decorated white surface with a "porcelain" appearance. The plating preserves the surface finish and topography of the substrate and makes it fully perceptible / visible. Thus, a glossy substrate with a circular wood grain pattern maintains its glossy appearance and the circular wood grain pattern remains visible. Similarly, a matte substrate with a Côtes de Genève pattern maintains its matte appearance and the Côtes de Genève pattern remains clearly visible.

[0033] The process described in this invention makes it possible to deposit a "porcelain"-like white plating onto all kinds of watch components, particularly attractive decorative parts. For example, the method according to the present invention can be used to deposit white plating onto internal and movement components such as dials, hands, appliqués, bars, plates, barrels, and rotors. In addition, the method of the present invention can also be applied to jewelry.

[0034] This makes it possible to obtain watch components with a porcelain-like white appearance while maintaining the surface finish and decoration of the components. [Explanation of Symbols]

[0035] 1. Watch components, circuit boards 10 1st layer, metal adhesive layer 11. Second layer, diffusion layer 12 hard layer 13. Final layer, pure metal layer 14 transparent layer, 15 Protective layer

Claims

1. A method for decorating a watch component (1) with white plating, - The steps of preparing the clock component (1) and placing the clock component in the deposition chamber, - A step of depositing a metal adhesive layer (10) over the entire watch component by physical vapor deposition, - By physical vapor deposition, an aluminum diffusion layer (11) is deposited over the entire watch component while a reagent gas is flowed through it, the rate of the reagent gas is controlled so that an aluminum layer doped with 0.5 atomic% to 10 atomic% of the reagent gas is obtained, and the aluminum layer crystallizes in the form of a faceted crystal structure, - A step of depositing a hard layer (12) on the diffusion layer (11) to maintain the structure of the diffusion layer while increasing the resistance of the diffusion layer (11) to scratches and other mechanical damage, - A step of depositing a pure metal layer (13) to increase the reflectivity of the already deposited layer, - A step of depositing a transparent layer (14) using the ALD method or another vacuum deposition method in order to improve the white appearance by interference effect and to chemically protect the layer deposited in the previous step, - A decorative method comprising the step of depositing a transparent protective layer (15) using the ALD method or another vacuum deposition method.

2. The decorative method according to claim 1, characterized in that the adhesive layer (10) is a metal layer or a metal alloy layer that can be selected from aluminum, titanium, titanium aluminide, or chromium.

3. The decorative method according to claim 1, characterized in that the adhesive layer (10) has a thickness of 30 nm to 100 nm, preferably 50 nm.

4. The decorative method according to claim 1, wherein the diffusion layer (11) has a thickness of 300 nm to 6,000 nm, preferably 1,000 nm to 2,000 nm, and preferably 1,500 nm.

5. The decorative method according to claim 1, wherein the hard layer (12) has a thickness of 100 nm to 3,000 nm, preferably 400 nm to 2,000 nm, and preferably 1,000 nm.

6. The decorative method according to claim 1, wherein the hard layer (12) is made of DLC, nitride or carbonitride, oxynitride, or a material selected from titanium oxide, titanium aluminum oxide, silicon oxide, aluminum oxide, nickel oxide, or chromium oxide.

7. The decorative method according to claim 1, wherein the pure metal layer (13) has a thickness of at least 5 nm.

8. The decorative method according to claim 1, wherein the pure metal layer (13) is made of a metal having high reflectivity such as aluminum, silver, rhodium, or chromium.

9. The decorative method according to claim 1, wherein the transparent layer (14) comprises a coating of a transparent dielectric layer.

10. The decorative method according to claim 9, wherein the transparent dielectric layer has a refractive index of 1.38 to 2.6 at a wavelength of 633 nm and a thickness of 5 nm to 500 nm.

11. The decorative method according to claim 1, wherein the protective layer (15) has a thickness of 0.5 nm to 20 nm, preferably 2 nm.

12. The decorative method according to claim 1, wherein the protective layer (15) is selected from the following materials: titanium dioxide, aluminum oxide, silicon dioxide, and silicon nitride.

13. The decoration method according to claim 1, wherein the reagent gas used for the diffusion layer (11) is oxygen, nitrogen, or a mixture thereof.

14. Watch components such as dials, hands, appliqués, bars, plates, rotors, barrels, or clasps having a white surface obtained by the method described in claim 1.

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