CH718465A2 - Process for manufacturing a ceramic-based watch or jewelery casing part with a structured decor. - Google Patents

Abstract

The invention relates to a method for manufacturing a watch or jewelery casing part comprising the following successive steps: production (101) of a base in a ceramic material substrate, mirror polishing (2) of the base on at least one face called the "display face" intended to be visible to a user, machining (103) by laser machining according to predefined patterns during a preliminary step (105), oxidation (104) of the base by heat treatment. The invention also relates to a dial obtained by such a process.

Description

Technical field of the invention

[0001] The invention relates to the field of watchmaking or jewelry, and relates more particularly to a method of manufacturing a piece of watchmaking or jewelry casing with a ceramic base and structured decoration. The invention also relates to a timepiece dial manufactured by implementing said method.

Technology background

[0002] To give a particular visual appearance, for example a frosted appearance, to a watch or jewelry casing part, there are several well-known methods in the state of the art.

[0003] Indeed, it is known to deposit a varnish or an organic lacquer, the composition of which gives a metallic appearance to the trim part.

[0004] It is also known practice to use a mineral material of the opal or quartz type as the substrate for the covering part.

[0005] Furthermore, a method is also known comprising a first step in which the surface of a trim piece is structured, by stamping or by laser, with patterns or a structure of the grained type. The covering part is made of a metal, for example aluminum or a copper alloy.

[0006] Next, the surface is polished, then covered with a layer of a white material, for example silver, by galvanic means or by a thin layer deposition method under vacuum, for example of the deposition type. physical vapor phase (known by the acronym in English language "PVD" for "Physical Vapor Deposition") or atomic thin layer deposition (known by the acronym in English language "ALD" for Atomic Layer Deposition).

[0007] However, the implementation of these methods does not give complete satisfaction, insofar as they do not make it possible to obtain certain aesthetic characteristics, in particular, an appearance of metallic luster, that is to say a high reflectivity, high color intensity, etc.

Summary of the invention

[0008] The invention solves the aforementioned drawbacks by proposing a solution making it possible to produce a trim part whose visual appearance has a high shine and luster, and in particular an aesthetic appearance of particularly intense and pronounced frost.

[0009] To this end, the present invention relates to a method of manufacturing a watch or jewelery covering part comprising the following successive steps: production of a base in a ceramic material substrate, mirror polishing of the base on at least one side called the "display side" intended to be visible to a user, machining by laser machining of predefined patterns during a preliminary step, on the display face, oxidation of the base by heat treatment.

[0010] Advantageously, the patterns appear visually, on the one hand, thanks to the mechanical surface structuring carried out during the laser machining step, and on the other hand, thanks to the difference in surface state between said patterns. , with a matte appearance, and the rest of the display surface, with a shiny appearance.

[0011] The mechanical structuring of the display surface thus makes it possible, by modifying the light diffraction, to generate optical effects reinforcing the appearance of frost on said surface.

[0012] In particular embodiments, the invention may also comprise one or more of the following characteristics, taken in isolation or in all technically possible combinations.

[0013] In particular embodiments, the base is made of a zirconium oxide substrate.

[0014] In particular embodiments, the base is made of glass, stone, alumina or sapphire.

[0015] In particular embodiments, the base is made so as to have a thickness of between 0.1 mm and 1.2 mm, preferably 0.4 mm.

In particular modes of implementation, during the preliminary step, the predefined patterns are obtained by processing a digital image, so as to obtain an image formed of black pixels and white pixels, said black pixels or white pixels representing the patterns to be machined.

In particular modes of implementation, during the preliminary step, the image obtained is formed of black pixels, white pixels, and pixels in shades of gray, said black pixels, white pixels or pixels in shades of gray representing the patterns to be machined.

[0018] In particular embodiments, the shade of gray of the pixels is representative of the machining depth. In other words, the shade of gray of each pixel in shade of gray is representative of the machining depth of the area of the pattern corresponding to each of said pixels.

[0019] In particular embodiments, the graphic content of the digital image has a dendritic shape, such that the patterns machined on the base give a dendritic appearance to the base.

[0020] In particular embodiments, the area of the patterns represents between 25% and 75% of the display area.

[0021] In particular embodiments, the patterns have a depth of between 200 nm and 50 μm, preferably between 5 μm and 10 μm.

[0022] In particular modes of implementation, during the step of oxidation of the base, the heat treatment is carried out at a temperature between 500 and 1000 degrees Celsius.

[0023] In particular modes of implementation, a step of depositing a thin layer on a face of the base opposite the display face, called the "lower face", is carried out after the step of oxidation.

[0024] In particular embodiments, the step of depositing a thin layer on the underside consists of applying a varnish.

In particular embodiments, a step of depositing a thin transparent or semi-transparent layer on the display face is carried out after the oxidation step.

According to another aspect, the present invention also relates to a timepiece dial, such as a watch, obtained by implementing a manufacturing method as described above.

Brief description of figures

Other characteristics and advantages of the invention will appear on reading the following detailed description given by way of non-limiting example, with reference to the appended drawings in which: FIG. 1 illustrates a flowchart representing the steps of a method of manufacturing a watch or jewelery casing part according to the invention.

Detailed description of the invention

The present invention relates to a method of manufacturing a watch or jewelery covering part, the steps of which are represented schematically by the flowchart of Figure 1.

The method according to the invention comprises the successive steps of: production 101 of a base in a ceramic material substrate, mirror polishing 102 of the base on at least one face called the "display face" intended to be visible to a user, machining 103 by laser machining of predefined patterns during a preliminary step 105, on the display face, oxidation 104 of the base by heat treatment.

The steps of the manufacturing process are described in detail below.

The base is preferably made from a zirconium oxide substrate. This material advantageously has the appropriate optical and mechanical characteristics to form the base, in addition to being relatively easy to work with.

[0032] Alternatively, the substrate can be any ceramic material, such as glass, stone, alumina, sapphire, etc.

[0033] Preferably, the substrate has a single color, for example a white color.

The base is made so as to have a thickness of between 0.1 mm and 1.2 mm, preferably 0.4 mm.

The mirror polishing step 102 of the display face of the base allows said display face to obtain a shiny appearance, having a high reflective power.

The machining step 103 is preferably carried out by nanosecond, picosecond or femtosecond laser engraving. The machining step generally designates any material removal operation, such as engraving or marking.

During the machining step 103, the laser engraving is performed by a controlled laser machining machine so as to machine patterns on the surface of the display face.

These patterns are defined following the processing of a predetermined digital image during the preliminary step 105. More precisely, the processing of the predetermined digital image consists in obtaining, thanks to an image processing algorithm, a transformed digital image comprising a set of black pixels and white pixels representative in particular of the luminosity and of the contrast of the predetermined digital image.

More specifically, the black pixels correspond to the darkest pixels of the predetermined digital image, that is to say those whose brightness is below a predefined threshold, and the white pixels correspond to the lightest pixels. of the predetermined digital image, that is to say those whose brightness is greater than the predefined threshold.

The black pixels or the white pixels represent the patterns to be machined.

It is thus possible to machine, on the base, patterns representative of the graphic content, that is to say the visual aspect, of one or more predetermined digital images.

In another exemplary implementation of the present invention, during the preliminary step 105, the image obtained is formed, in addition to black pixels and white pixels, of pixels in shades of gray. Analogously to white and black pixels, the shade of gray of each grayscale pixel corresponds to the brightness of the corresponding pixel.

The shade of gray of each pixel in shade of gray is representative of the machining depth of the area of the pattern corresponding to each of said pixels.

Preferably, in the method according to the invention, the graphic content of the digital image has a dendritic shape, so that the patterns machined on the base give a dendritic appearance to the display face.

The patterns can be arranged randomly on the surface of the display face or in predefined zones.

[0046] Advantageously, the area of the patterns represents between 25% and 75% of the display area, preferably between 40% and 60%. In this way, the dendritic appearance of the display face is reinforced.

During the machining step 103, the patterns are machined so as to have a depth comprised between 200 nm and 50 μm, a presence between 5 μm and 10 μm.

[0048] The intensity of the visibility of the patterns depends on this depth. In other words, the deeper the patterns are machined, the more visible they are.

The laser machining produces a local sublimation of the material of the substrate, at the level of the machined pattern, and consequently a heating producing a change in hue.

The oxidation step 104 of the base by heat treatment advantageously allows the base to regain its initial color.

Preferably, during this oxidation step 104 of the base, the heat treatment is carried out at a temperature between 500 and 1000 degrees Celsius.

[0052] Thanks to the steps of the manufacturing process according to the present invention, the trim part obtained advantageously has a high shine and luster.

[0053] Furthermore, since the machined patterns have a matte appearance and the rest of the display surface has a shiny appearance, the display face generates an optical effect which, in combination with the dendritic appearance of the patterns, helps to reinforce the appearance of frost.

Preferably, a step 106 of depositing a thin layer on a face of the base opposite to the display face, called the "lower face", can be carried out after the oxidation step 104.

This step has the effect of opacifying the substrate and possibly increasing the mechanical characteristics of the covering part, for example in the case where the thickness of the base is particularly low.

More specifically, the step 106 of depositing a thin layer on the underside consists of applying a varnish.

Furthermore, a step 107 of depositing a thin layer on the display face can be performed after the oxidation step 104, said thin layer being transparent or semi-transparent.

This thin layer then has the effect of protecting the base from any chemical or mechanical aggression and possibly of modifying its tint.

This deposition step 107 may consist of the application of a thin layer by physical vapor deposition (known by the acronym in English “PVD” for “physical vapor deposition”).

Alternatively, this deposition step 107 may consist of applying a varnish or a lacquer, for example structured.

It should be noted that the deposition steps 106 and 107 are independent of each other in the sense that one can be carried out without the other being, and where the order of performance of these steps is irrelevant, although the flowchart of Figure 1 illustrates the performance of the deposit step 106 before the performance of the deposit step 107.

[0062] In a preferred application, the timepiece or jewelry casing part manufactured by implementing the method according to the invention is a timepiece dial, such as a watch.

[0063] More generally, the trim part manufactured by the process according to the invention can be constituted by any decorative article in the fields of watchmaking or jewelery intended to be visible to a user.

Claims (15)

1. A method of manufacturing a watch or jewelery trim part, characterized in that it comprises the following successive steps: – production 101 of a base in a ceramic material substrate, – mirror polishing 102 of the base on at least one face called the “display face” intended to be visible to a user, – machining 103 by laser machining of predefined patterns during a preliminary step 105, on the display face, – 104 oxidation of the base by heat treatment. 2. Manufacturing process according to claim 1, in which the base is made of a zirconium oxide substrate. 3. Manufacturing process according to claim 1, wherein the base is made of glass, stone, alumina or sapphire. 4. Manufacturing process according to claim 1 to 3, wherein the base is made so as to have a thickness of between 0.1 mm and 1.2 mm. 5. Manufacturing process according to one of claims 1 to 4, in which, during the preliminary step 105, the predefined patterns are obtained by processing a digital image, so as to obtain an image formed of black pixels and of white pixels, said black pixels or white pixels representing the patterns to be machined. 6. Manufacturing method according to claim 5, wherein, during the preliminary step 105, the image obtained is formed of black pixels, white pixels, and pixels in shades of gray, said black, white or gray pixels. shades of gray representing the patterns to be machined. 7. Manufacturing method according to claim 6, in which the shade of gray of the pixels is representative of the machining depth. 8. Manufacturing process according to claim 5 to 7, in which the graphic content of the digital image comprises a dendritic shape, such that the patterns machined on the base give a dendritic appearance to the base. 9. Manufacturing process according to one of claims 1 to 8, in which the area of the patterns represents between 25% and 75% of the display area. 10. Manufacturing process according to one of claims 1 to 9, in which the patterns have a depth of between 200 nm and 50 μm. 11. Manufacturing process according to one of claims 1 to 10, wherein during the step of oxidation 104 of the base, the heat treatment is carried out at a temperature between 500 and 1000 degrees Celsius. 12. Manufacturing process according to one of claims 1 to 11, in which a step 106 of depositing a thin layer on a face of the base opposite to the display face, called the "lower face", is carried out after the oxidation step 104. 13. Manufacturing process according to claim 12, in which the step 106 of depositing a thin layer on the underside consists of applying a varnish. 14. Manufacturing process according to one of claims 1 to 13, in which a step 107 of depositing a thin transparent or semi-transparent layer on the display face is carried out after the oxidation step 104. 15. Timepiece dial obtained by implementing a method according to one of claims 1 to 14.