Item with a backlit plique-à-jour enamel decoration and method for manufacturing the same

Abstract

The invention relates to an article with a backlit window enamel ornament and a method of manufacturing the same. The invention relates to a method for manufacturing an article (1) comprising a through-decoration (2) forming a so-called backlit window enamel, comprising the following steps: obtaining a semi-finished product (5); -removing a portion of the semi-finished product (5) from the inner face (5b) of the semi-finished product (5) in order to produce a decoration (2a) that does not penetrate to the outer face (5a); -depositing one or more layers of enamel (3) in the non-penetrating ornament (2a) starting from the inner face (5b); depositing a layer of luminescent material (4) on the enamel (3) starting from the inner face (5b); depositing a protective layer (6) on the luminescent material layer (4); and machining the outer face (5a) to expose the enamel (3). The invention also relates to an article (1) comprising a through-decoration (2) made of a backlit window enamel.

Description

(19) State Intellectual Property Office (12) Invention Patent Application (10) Application Publication Number (43) Application Publication Date (21) Application Number 202510483829.X (22) Application Date 2025.04.17 (30) Priority Data 24171992.1 2024.04.23 EP (71) Applicant Comadour Company Address Locke, Switzerland (72) Inventor J. Romand (74) Patent Agency China Patent Agency (Hong Kong) Limited 72001 Patent Attorney Moody Zou Longhui (51) Int.Cl. B44C 5 / 00 (2006.01) B44C 1 / 26 (2006.01) (54) Invention Title Article with Backlit Hollow Enamel Decoration and Method of Manufacturing Thereof (57) Abstract Article with Backlit Hollow Enamel Decoration and Method of Manufacturing Thereof. The present invention relates to a method for manufacturing an article (1) comprising a through-hole ornament (2) forming a so-called backlit pierced enamel, the method comprising the steps of: - obtaining a semi-finished product (5); - removing a portion of the semi-finished product (5) from an inner surface (5b) to produce an ornament (2a) that does not penetrate to an outer surface (5a); - depositing one or more layers of enamel (3) within the non-penetrating ornament (2a) starting from the inner surface (5b); - depositing a layer of luminescent material (4) on the enamel (3) starting from the inner surface (5b); - depositing a protective layer (6) on the luminescent material layer (4); - machining the outer surface (5a) to expose the enamel (3). The invention also relates to an article (1) comprising a through-hole ornament (2) made of backlit pierced enamel. Claims 2 pages Description 3 pages Drawings 8 pages CN 120828610 A 2025.10.24 CN 1 20 82 86 10 A 1. A method for manufacturing an article (1) comprising a penetrating ornament (2), the penetrating ornament (2) being filled with at least one enamel (3) and a luminescent material (4) to form a so-called backlit peep enamel, the method comprising the steps of: - obtaining a semi-finished product (5) defining an outer surface (5a) and an inner surface (5b), the outer surface (5a) being a surface intended to face an observer, the inner surface (5b) being the opposite surface of the outer surface (5a); - removing a portion of the semi-finished product (5) from the inner surface (5b) to produce an ornament (2a) that does not penetrate to the outer surface (5a); or alternatively, in the preceding steps, directly obtaining the semi-finished product (5) having a non-peeting ornament (2a); - Deposit one or more layers of enamel (3) in the non-penetrating decoration (2a) starting from the inner surface (5b), and fire the enamel (3) after each layer has been deposited;- A layer of luminescent material (4) is deposited on the enamel (3) starting from the inner surface (5b); - A protective layer (6) is deposited on the luminescent material (4) layer starting from the inner surface (5b); - Preferably, the outer surface (5a) is machined by grinding to expose the enamel (3), and thus an article (1) having the penetrating decoration (2) is produced. 2. The method according to claim 1, wherein after the machining step, the outer surface (5a) is polished to increase the brightness of the penetrating decoration (2). 3. The method according to any one of the preceding claims, wherein the semi-finished product (5) is made of a material with a melting point greater than or equal to 650 °C. 4. The method according to any one of the preceding claims, wherein the deposition of one or more layers of enamel (3) is performed by liquid spraying, using a brush, or by spraying powder. 5. The method according to any one of the preceding claims, wherein the number of deposited enamel (3) layers is between 2 and 15, preferably between 3 and 10. 6. The method according to any one of the preceding claims, wherein during the step of depositing one or more layers of enamel (3), enamel (3) layers of different colors are deposited and / or colors within the same layer are modulated. 7. The method according to any one of the preceding claims, comprising the steps of: texturing the enamel (3) to form a structure (7) on the surface of the enamel (3), at the outer surface (5a), during the deposition of one or more layers of enamel (3), within the enamel (3), and / or on the surface of the enamel (3), at a layer of luminescent material (4). 8. The method according to the preceding claim, comprising the step of filling the structure (7) with the luminescent material (4). 9. An article (1) comprising an outer surface (5a) intended to face an observer and an inner surface (5b) opposite the outer surface (5a), the article (1) comprising a through-hole decoration (2) made of backlit peep enamel. 10. The article (1) according to the preceding claim, characterized in that the penetrating ornament (2) comprises, from the outer surface (5a), a layer of enamel (3), a layer of luminescent material (4), and a protective layer (6). 11. The article (1) according to any one of claims 9 to 10, wherein the thickness of the enamel (3) layer is greater than or equal to 0.5 mm, preferably greater than or equal to 0.8 mm. 12. The article (1) according to any one of claims 9 to 11, wherein the article (1) is an external timepiece component or a component of a movement. 13. The article (1) according to any one of claims 9 to 12, wherein the article (1) is an external timepiece component. 14. The article (1) according to any one of claims 9 to 13, wherein the article (1) is made of ceramic, sapphire, or cermet. Claims 1 / 2 page 2 CN 120828610 A15. The article (1) according to the preceding claim, said article (1) being made of zirconium oxide. Claims 2 / 2 Page 3 CN 120828610 A Article with Backlit Plique-à-jour enameled Decoration and Method of Manufacturing Thereof Technical Field

[0001] The present invention relates to a method for manufacturing articles with backlit plique-à-jour enameled decoration. The method according to the invention enables mass production at a reduced cost. The invention also relates to articles produced by this method. Background Art

[0002] Plique-à-jour enameling is a technique for applying enamel to a substrate without a bottom at the level of the enamel. The absence of any bottom allows light to pass through the transparent or translucent enamel. The result is a miniature stained glass effect.

[0003] Conventional plique-à-jour enameling techniques involve forming welded partitions with metal that remains stable during the firing of the enamel. During the continuous firing of the layers deposited layer by layer, the metal partitions, which are mainly made of gold or platinum due to their nature, may deform or even separate from the substrate, which greatly limits the number of kiln channels and the designs that can be produced.

[0004] Furthermore, a substrate is required during deposition and firing to ensure that the enamel does not extend beyond the spacers. Since the substrate is made of quartz, this is difficult to do on non-planar shapes. Conventional enamel is deposited by hand using a brush or oiler. Layers deposited using these methods are very thin, requiring dozens of layers to achieve a total thickness typically less than 0.5 mm. Due to the thinness, the resulting enamel is quite fragile.

[0005] Because this technique is cumbersome and poorly reproducible, timepieces with openwork enamel dials are unique pieces or produced in extremely limited quantities at high cost. To date, the lack of repeatability has hindered watch manufacturers from mass-producing timepieces.

[0006] In addition to this productivity aspect, luminous effects can be sought after for decoration, particularly for the bezel or dial markings. Summary of the Invention

[0007] The object of the present invention is to overcome the above-mentioned disadvantages by proposing a manufacturing method that allows for the mass production of pieces with openwork enamel decorations at low cost and with increased enamel strength. The invention also aims to give this openwork enamel decoration a luminous effect.

[0008] To this end, the present invention relates to a method for manufacturing an article comprising a through-hole decoration filled with at least one enamel and a luminescent material to form a so-called backlit pierced enamel, the method comprising the steps of:

[0009] - obtaining a semi-finished product defined with an outer surface and an inner surface, the outer surface being the surface intended to face an observer, and the inner surface being the opposite surface of the outer surface;

[0010] - removing a portion of the semi-finished product from the inner surface to produce a decoration that does not penetrate to the outer surface; or alternatively, in the preceding steps, directly obtaining said semi-finished product having a non-through-hole decoration;

[0011] - Deposit one or more layers of enamel within the non-through decoration, starting from the inner surface, and fire the enamel after each layer has been deposited;

[0012] - Deposit a layer of luminescent material onto the enamel, starting from the inner surface;

[0013] - Deposit a protective layer onto the luminescent material layer, starting from the inner surface;

[0014] - Preferably, the outer surface is machined by grinding to expose the enamel, and thus an article with a through decoration is produced. Specification 1 / 3 page 4 CN 120828610 A

[0015] Preferably, the through decoration is then polished.

[0016] This method is highly repeatable, thus allowing for mass production at very low cost.

[0017] This method allows for the deposition of thick enamel layers, thus making it possible to obtain enamel with a total thickness greater than or equal to 0.5 mm and a limited number of layers (typically less than 10 layers). This greater thickness of the enamel compared to enamels in the prior art means that it is less brittle and can therefore be used to make external parts subjected to significant stress, such as watch frames.

[0018] More generally, unlike standard lacquered watch frames, enamel, rather than lacquer, provides excellent chemical and mechanical resistance. Unlike lacquer, enamel is also a material considered noble in the watchmaking and jewelry industries.

[0019] The polymerization of the luminescent material and the protective layer during the deposition step occurs at very low temperatures (typically around 80 °C), which does not damage the enamel. The protective layer (which is typically lacquer) protects the luminescent material from the external environment but also reflects the light back to the enamel side. The outer enamel protects the luminescent decoration from mechanical abrasion.

[0020] The invention is also based on the ability to simultaneously polish the substrate and the enamel, ensuring optimal surface finish for both materials. Polishing the enamel also means that the part can be given its final, shiny, translucent appearance without having to be reheated in a kiln.

[0021] Transparent enamel decorations will produce a depth that is currently unattainable. Furthermore, because the luminescent material is positioned far back, the luminescence will be perceptible even in brightly lit environments. The colors of luminescent materials and translucent enamels can also be combined to obtain new luminescent color panels. Color gradients can also be deposited, for example, by spraying onto the enamel.

[0022] Figures 1a to 1f illustrate six steps of the method according to the invention. In each figure, an illustrated cross-sectional view of a portion of an article or semi-finished product and a three-dimensional view of a portion of an article or semi-finished product are shown. The three-dimensional views in Figures 1a and 1f are top views (i.e., from the external surface) of the semi-finished product or article, while views 1b to 1e are bottom views (i.e., from the internal surface) of the semi-finished product.

[0023] Figures 2a to 2c illustrate cross-sectional views of the article for additional and optional steps in the method according to the invention.

[0024] Figure 3 is a three-dimensional view of the article produced by the method. Detailed Description

[0025] This invention relates to a method for manufacturing articles with backlit openwork enamel decorations. The article can be, for example, a timepiece component. More specifically, it can be an external component selected from a non-exhaustive list including: a center section, case back, bezel, crown, pushers, strap links, strap, clasp, buckle, dial, and hands. It can also include components of the movement, such as a oscillating weight. This method is particularly suitable for manufacturing articles subjected to high stress, such as external components. The invention will now be described in more detail with respect to bezels.

[0026] This manufacturing method is suitable for any substrate with a melting point higher than the enamel firing temperature, which, depending on the composition of the enamel, is typically between 650°C and 1100°C. This method is particularly suitable for substrates made of hard materials, such as ceramics (e.g., silicon nitride, zirconium oxide, or alumina), or such as sapphire or cermet. Some ceramics, particularly ZrO2, have excellent mechanochemical adhesion to enamel, and their coefficients of thermal expansion are very close, resulting in openwork articles maintaining excellent mechanical strength. For example, for high-temperature enamel, these materials undergo firing cycles up to 1000°C and resist the thermal shock of rapid firing cycles.

[0027] The method is illustrated in Figures 1a to 1f with respect to the watch frame in six steps from a) to f). In the first step a), an article without any decoration is obtained, which will be referred to as semi-finished product 5. Then, in the second step b), a non-penetrating decoration 2a is produced from the inner surface 5b of the semi-finished product 5. The non-penetrating decoration can be produced, for example, by laser ablation. Optionally, if a semi-finished product with the non-penetrating decoration 2a is obtained directly in step a), this step b) can be omitted, for example, by injection molding. In the third step c), enamel 3 is deposited in the decoration 2a, also starting from the inside of the semi-finished product 5. Although not illustrated in Figure 1c, during this step, the inner surface 5b is preferably placed in an upper position to allow for enamel deposition. Ideally, for industrial production, deposition is performed by liquid spraying. Alternatively, it can be done manually with a brush for rapid deposition or by spraying powder. The semi-finished product 5 is then fired to vitrify the deposited enamel. Preferably, multiple layers of enamel are deposited, with a firing cycle performed after each deposition step to ensure the enamel is bubble-free. Different colors of enamel layers can be deposited and / or the color of each deposited enamel layer can be varied. Typically, the total thickness of the enamel layers is greater than or equal to 0.5 mm, preferably greater than or equal to 0.8 mm, with a maximum total thickness of 1.5 mm or more, depending on production time. In the fourth step d), once the decoration has been at least partially filled with enamel and fired, a layer of luminescent material 4 is deposited on the enamel 3, i.e., again starting from the inside of the semi-finished product, with the inside surface preferably in the upper position. For example, the luminescent material can be...It is a phosphorescent pigment added to a lacquer or adhesive. This material provides a variety of luminescent colors, including blue, green, purple, white, yellow, orange, and pink, etc. In the fifth step e), a protective layer 6 (such as lacquer) is deposited on the luminescent material layer 4, with the inner surface preferably in the upper position. Then, the sixth machining step f) is preferably performed by grinding on the upper surface 5a of the semi-finished product 5 to expose the enamel 3, thus obtaining a through-beam decoration 2 illuminated from the inside by the luminescent material 4. A final polishing operation can then be performed to make the polished surface perfectly shiny and to ensure good transparency of the enamel. The resulting frame is shown in FIG. 3.

[0028] Optionally, the outer surface can be subjected to finishing treatments, such as satin finishing or laser texturing as described below. The enamel can also be texturized on the inner surface or within the enamel.

[0029] Optional texturing steps are illustrated in FIG. 2a to FIG. 2c. These steps involve texturing the enamel 3, for example by laser engraving, to produce the structure 7. This structure can remain as is to give a specific aesthetic effect, or it can then be filled with a material such as luminescent material 4. In Figure 2a, after the machining step, the enamel 3 is textured on the visible surface, and the luminescent material 4 is added to the structure 7. In Figure 2b, the structure 7 is created within the enamel 3. In Figure 2c, the structure 7 is created before the deposition of the luminescent material layer 4, when the final layer of enamel 3 is deposited below the semi-finished product.

[0030] The obtained article 1 has the following characteristics. It is provided with at least one through-decorative element 2, which is filled with a stack of several layers, which, starting from the outer surface inward, are: an enamel layer 3 formed by depositing and firing one or more enamel layers, a luminescent material layer 4, and a protective layer 6. The number of deposited enamel layers is typically between 2 and 15, preferably between 3 and 10, and the total thickness of the obtained enamel is typically greater than or equal to 0.5 mm, preferably greater than or equal to 0.8 mm, wherein the maximum value can reach 1.5 mm, or even more in cases where the production time is long.

[0031] Optionally, referring to the additional steps in Figures 2a to 2c, the article 1 includes one or more structures 7 on its surface or in the enamel layer 3, the structures 7 being filled with material, and more specifically filled with luminescent material 4. These structures may be arranged on the visible surface, facing the inner surface opposite the visible surface, or in between. [Figure 1a] [Figure 1b] [Figure 1c] [Figure 1d] [Figure 1e]Sheet 5 / 8 of the drawings of the specification, 11, CN 120828610 A, Figure 1f; Sheet 6 / 8 of the drawings of the specification, 12, CN 120828610 A, Figure 2a, Figure 2b; Sheet 7 / 8 of the drawings of the specification, 13, CN 120828610 A, Figure 2c, Figure 3; Sheet 8 / 8 of the drawings of the specification, 14, CN 120828610 A. Abstract. Disclosed is an item with a backlit plique-à-jour enamel decoration and method for manufacturing the same. The invention relates to a method for manufacturing an item (1) comprising a through-decoration (2) forming a so-called backlit plique-à-jour enamel, the method comprising the steps of: - obtaining a blank (5); - removing part of the blank (5) from the inner face (5b) of the blank (5) to produce a decoration (2a) that does not pass through to the outer face (5a); - depositing, from the inner face (5b), one or more layers of enamel (3) within the non-through decoration (2a); - depositing, from the inner face (5b), a layer of luminescent material (4) on the enamel (3); - depositing a protective layer (6) on the layer of luminescent material (4); - machining the outer face (5a) to reveal the enamel (3). The invention furtherrelates to the item (1) comprising a through-decoration (2) made of a backlit plique-à- jour enamel.

Claims

1. A method for manufacturing an article (1) comprising a through-decor (2) filled with at least one enamel (3) and a luminescent material (4) to form a so-called backlit empty window enamel, said method comprising the following steps: - obtaining a semi-finished product (5) defining an external face (5a) intended to face the observer and an internal face (5b) opposite the external face (5a); - removing a portion of the semi-finished product (5) from the internal face (5b) to create a non-through-decor (2a) which does not penetrate to the external face (5a); or alternatively, in the previous step, obtaining directly the semi-finished product (5) with a non-through-decor (2a); - depositing one or more layers of enamel (3) within the non-through-decor (2a) starting from the internal face (5b) and firing the enamel (3) after having deposited each layer; - depositing a layer of luminescent material (4) on the enamel (3) starting from the internal face (5b); - depositing a protective layer (6) on the layer of luminescent material (4) starting from the internal face (5b); - machining the external face (5a), preferably by grinding, to reveal the enamel (3) and thus produce the article (1) with the through-decor (2).

2. The method according to claim 1, comprising a step of polishing the external face (5a) after the machining step to increase the brightness of the through-decor (2).

3. The method according to any one of the preceding claims, wherein the semi-finished product (5) is made of a material having a melting point greater than or equal to 650°C.

4. The method according to any one of the preceding claims, wherein the deposition of one or more layers of enamel (3) is performed by liquid spraying, using a brush or by spraying a powder.

5. The method according to any one of the preceding claims, wherein the number of deposited enamel (3) layers is between 2 and 15, preferably between 3 and 10.

6. The method according to any one of the preceding claims, wherein, during the step of depositing one or more layers of enamel (3), layers of enamel (3) of different colors are deposited and / or the color within the same layer is modulated.

7. The method according to any one of the preceding claims, comprising a step of texturing the enamel (3) to form structures (7) on the surface of the enamel (3), at the external face (5a), during the deposition of the one or more layers of enamel (3) within the enamel (3) and / or on the surface of the enamel (3), at the layer of luminescent material (4).

8. The method according to the preceding claim, comprising a step of filling the structures (7) with the luminescent material (4).

9. An article (1) comprising an external face (5a) intended to face the observer and an internal face (5b) opposite the external face (5a), the article (1) comprising a through-decor (2) made of a backlit empty window enamel.

10. Article (1) according to the preceding claim, characterized in that Said through-decor (2) comprises, starting from said external face (5a), a layer of enamel (3), a layer of luminescent material (4) and a protective layer (6).

11. Article (1) according to any one of claims 9 to 10, wherein the thickness of the layer of enamel (3) is greater than or equal to 0.5 mm, preferably greater than or equal to 0.8 mm.

12. Article (1) according to any one of claims 9 to 11, which is an external timepiece component or a component of a movement.

13. Article (1) according to any one of claims 9 to 12, which is an external timepiece component.

14. Article (1) according to any one of claims 9 to 13, which is made of ceramic, sapphire or cermet.

15. Article (1) according to the preceding claim, which is made of zirconia.

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