CH720046A2 - Method of manufacturing a covering component comprising a diffraction grating. - Google Patents

Abstract

The invention relates to a method for manufacturing a trim component (10) of a watch, a fashion item or an item of jewelry, characterized in that it comprises the following steps : – deposition of an opaque base layer (12) on all or part of the surface of an internal face (110) of a substrate (11) made of a transparent material, – localized ablation of the base layer ( 12) by laser machining, so as to form at least one pocket (14) whose bottom has a diffraction grating (15). The invention also relates to a watch dial and a fashion item obtained by such a process.

Description

Technical field of the invention

[0001] The invention relates to the field of watchmaking, fashion items, jewelry or jewelry, and relates more particularly to a method of manufacturing a component for dressing a watch, a article of fashion, jewelry or jewelry, said component comprising a diffraction grating.

[0002] In the present text, the notion of “fashion article” includes articles or accessories of clothing, such as belts, shoes, clothing, etc., and also includes articles of eyewear, articles of telephone, or any other decorative object.

Technology background

[0003] In the field of watchmaking in particular, the exterior components for watches, in particular the dial, the flange, the bezel, etc., can have, for decorative purposes, decorations made from thin layers deposited on the surface of a substrate. In particular, these thin layers make it possible to color the covering component, for example to print patterns on its surface.

[0004] The surface of a covering component can also be structured, for example by machining, in order to present a certain relief.

[0005] Decorations on covering parts can also be made so as to generate light diffraction phenomena and thus present a color which can vary depending on the orientation of a user's direction of observation and/or or the orientation of a light source. These phenomena are generated via diffraction gratings produced on the covering component, as described in document CH715906. This type of decor is attractive in that it is scalable and can be very varied.

[0006] However, the production of this type of decoration imposes several constraints, in particular a high requirement in terms of controlling manufacturing tolerances and surface condition. Furthermore, this type of decoration is only made on metallic materials. There is therefore a need to be able to produce decorations with diffraction gratings in a repeatable manner, while guaranteeing compliance with manufacturing requirements, while diversifying the nature of the material(s) constituting the covering component.

Summary of the invention

[0007] The invention relates, for this purpose, to a method of manufacturing a component for dressing a watch, a fashion item or an item of jewelry, comprising the following steps: – deposition of an opaque base layer on all or part of the surface of an internal face of a substrate made of a transparent material, – localized ablation of the base layer by laser machining, so as to form at least one pocket whose bottom has a diffraction grating.

[0008] Carrying out the ablation step on the base layer rather than on the substrate advantageously makes it possible to produce the diffraction grating with a greatly reduced energy level, due to the difference between their thresholds. ablation.

[0009] In addition to authorizing the choice of any transparent material to constitute the substrate, in particular a transparent material having a very high ablation threshold such as sapphire or glass, the method according to the invention makes it possible to guarantee excellent repeatability and control of manufacturing tolerances due to the low energy levels involved.

[0010] In particular modes of implementation, the invention may also include one or more of the following characteristics, taken in isolation or in all technically possible combinations.

[0011] In particular modes of implementation, the bottom of the pocket is formed by the substrate and/or by the base layer.

[0012] In particular modes of implementation, several localized ablation steps are carried out so as to produce a plurality of diffraction gratings.

[0013] In particular modes of implementation, the method comprises a polishing step carried out before the step of depositing the base layer, in which the internal face of the substrate is polished.

[0014] In particular modes of implementation, the method comprises an etching step in which all or part of the base layer is eliminated over its entire thickness without the internal face of the substrate being impacted.

[0015] In particular modes of implementation, the method comprises a step of depositing a secondary layer in which an opaque secondary layer is deposited at least on the diffraction grating.

[0016] In particular modes of implementation, during the etching step, part of the secondary layer is eliminated so as to conform said layer to a predefined shape, without the internal face of the substrate being impacted.

[0017] In particular modes of implementation, an anti-reflective coating is deposited on an external face of the substrate opposite the internal face.

[0018] According to another object, the present invention relates to a watch dial formed by implementing the method as previously described.

[0019] According to yet another object, the invention relates to a fashion article comprising a covering component formed by implementing the method as described above.

Brief description of the figures

[0020] 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: – Figure 1 shows schematically in sectional view, a covering component being produced by implementing a step of a manufacturing process according to the invention, – Figures 2 to 5 schematically represent in sectional view, a covering component obtained by the implementation of the manufacturing process according to the invention in different examples of implementation.

Note that the figures are not to scale.

Detailed description of the invention

The present invention relates to a method of manufacturing a covering component 10 as shown in Figures 2 to 5 in different examples of implementation of said method.

[0023] The trim component 10 can advantageously constitute a trim component for a watch, such as a dial, a trim component for a fashion item, or an item of jewelry. .

[0024] The terms “fashion articles” define in the present text any article or accessory of clothing, such as a belt, a shoe, a piece of clothing, etc., and also includes articles of eyewear, articles of telephony, such as phone cases, or any decorative object.

The manufacturing process comprises a first step of depositing a thin layer, called a “base layer” 12, opaque, on all or part of the surface of an internal face 110 of a substrate 11 made in a transparent material, as shown in Figure 1. It should be noted that the term “transparent” designates in this text an ability of a material to allow all or part of light radiation to pass through, in particular light visible to the naked eye. Such a transparent material can be sapphire, glass, etc.

The deposition of the base layer 12 can be carried out by a method of physical deposition by vapor phase, of chemical deposition by vapor phase, or by any other method suitable to those skilled in the art. For example, the base layer 12 can be made of metallic material, in particular Cr, Au, Ti, Zr, of dielectric material, alone or of alloy, of oxide and/or nitride, for example of CrTiO2.

The internal face 110 of the substrate 11 is opposite an external face 111 intended to be oriented towards an external environment, the internal face 110 being intended to be oriented toward an internal environment, for example facing a watch movement, in the case in which the covering component 10 is a component of a watch.

Preferably, the internal face 110 is polished during a preliminary polishing step, prior to the deposition of the base layer 12.

[0029] The method comprises, following the step of deposition of the base layer 12, a step of localized ablation of the base layer 12 by laser machining, so as to form, in the thickness of the layer of base 12, one or more pockets 14 whose bottom has a diffraction grating 15, as shown in Figure 2. The pocket 14 extends between an external face 120 of the base layer 12 and the bottom, in one direction materializing the thickness of the base layer 12.

In the present description of the invention and in accordance with the figures, reference is made below to a single pocket 14 and consequently to a single diffraction grating 15 to facilitate reading of the text.

Such a diffraction grating 15 is formed by the periodic repetition of a diffracting pattern.

[0032] For example, the diffraction grating is formed by a plurality of parallel streaks spaced from each other by a regular pitch, for example a few micrometers, typically between 2 and 20 μm.

[0033] By way of example, the laser used for laser machining can be a femtosecond laser, having a pulse energy of a few micro joules, for example between 1 and 5 µJ, and a repetition frequency of several hundreds of kilohertz, for example between 300 and 500 kHz.

[0034] In the exemplary embodiment shown in Figures 2 to 5, the pocket 14 opens onto the internal face 110 of the substrate 11, the diffraction grating 15 being formed on said internal face 110. In other exemplary embodiments of the invention, in particular as a function of laser machining parameters, such as the power or energy of the laser, the position of the focal point, etc., and/or as a function of the material constituting the base layer 12, the diffraction grating 15 can be formed by the internal face 110 of the substrate 11 or by a mixture of the materials of the base layer 12 and of said substrate 11.

[0035] Advantageously, in order to enrich the decoration, the method according to the invention can comprise several localized ablation steps so as to generate a plurality of diffraction gratings 15 so as to represent a particular pattern. These diffraction gratings 15 can be formed so as to be different from each other, for example, the orientation of their respective streaks, the number and dimensions of their streaks or their separation pitches can be different. In addition, the diffraction gratings 15 can be generated on portions of the internal face 110 of the substrate 11 inclined relative to each other.

[0036] In summary, the ablation steps can be carried out with different parameters depending on the desired appearance of the diffraction gratings 15 to be produced, the determination of the values of these parameters being within the reach of those skilled in the art.

The localized ablation generating the pocket 14 and the diffraction grating 15 simultaneously, the diffraction grating 15 coincides perfectly with the pocket 14 with which it is generated. Compliance with the alignment tolerances between the external face 120 of the base layer 12 and the diffraction grating 15 is therefore guaranteed.

[0038] Advantageously, the method can comprise an etching step in which a part of the base layer 12 is eliminated over its entire thickness so as to conform said base layer 12 according to a predefined shape, without the internal face 110 of the substrate 11 is not impacted, as shown in Figure 3. This characteristic helps to enrich the decorations that can be made on the covering component 10. Such an engraving step can be implemented by photolithography, laser machining, etc.

Alternatively, during the etching step, the entire base layer 12 can be eliminated over its entire thickness.

[0040] In the exemplary embodiments described above and shown in Figures 2 and 3, the user is intended to see the decoration of the covering component 10 from the external face 111, through said substrate 11, or from the internal face 110 according to the arrangement of said covering component 10 within the watch, jewelry or fashion item.

[0041] When the user is intended to see the decoration of the covering component 10 from the external face 111, through said substrate 11, the latter advantageously has the effect of protecting the base layer 12 from potential attacks from the external environment .

[0042] In an example of implementation of the invention, the method may comprise a step of depositing a secondary layer 13, in which an opaque secondary layer 13 is deposited on the diffraction grating 15 and on the layer of base 12, if the latter is not completely eliminated during an etching step or when no etching step has been implemented. If an etching step has been implemented and the entire base layer 12 has been eliminated, the secondary layer 13 is also deposited against the internal face 110 of the substrate 11, as shown in Figure 4.

[0043] In this exemplary embodiment shown in Figures 4 and 5, the user is intended to see the decoration of the covering component 10 only from the external face 111 through said substrate 11.

The secondary layer 13 advantageously makes it possible to increase the reflection of the diffracted light rays, and thus to increase the liveliness and contrast of the decoration generated. For this purpose, the layer can be made of metallic, ceramic, oxide and/or nitride material.

[0045] In the example of implementation shown in Figure 5, the etching step can consist of concomitantly eliminating a part of the base layer 12 and a part of the secondary layer 13, so as to conform said layers according to a predefined shape, without the internal face 110 of the substrate 11 being impacted. The eliminated part of the secondary layer 13 is superimposed on that of the base layer 12.

[0046] Advantageously, an anti-reflective coating (not shown in the figures) can be deposited on the external face 111 of the substrate 11. Such an anti-reflective coating makes it possible to promote the transmission of incident light rays and to minimize, or even eliminate, reflections. of light radiation incident on the external face 111 of the substrate 11. Thus, this characteristic makes it possible to intensify the appearance of the diffraction phenomenon.

[0047] An anti-reflective coating can also be deposited on the base layer 12 or on the secondary layer 13 according to the example of implementation of the invention considered, and possibly on the internal face 110 of the substrate 11 if a step of engraving was carried out.

[0048] Note that, thanks to the characteristics of the invention, the visual appearance of the decoration of the covering component 10 can be particularly rich and attractive to the extent that in addition to the possible colors of the base layer 12 and possibly of the secondary layer 13, the appearance of the diffraction grating 15 is added. Furthermore, the method according to the invention makes it possible to generate a visual effect of depth between the base 12 and secondary 13 layers and the diffraction grating 15 .

[0049] Furthermore, the base layer 12 advantageously makes it possible to produce, on a transparent substrate 11, a decoration with a diffraction grating 15 by laser machining requiring low power, which makes it possible to guarantee better control of the repeatability of machining, and consequently, to ensure constant compliance with manufacturing tolerances. Furthermore, carrying out machining requiring high power would cause an alteration of the surface state of the internal face 110 of the substrate 11 leading to a mattification of its surface, in addition to the uncertainties generated as to compliance with the dimensional requirements of the substrate. trim component 10.

More generally, it should be noted that the modes of implementation and embodiment considered above have been described by way of non-limiting examples, and that other variants are therefore possible.

In particular, the base layer 12 and/or the secondary layer 13 can be constituted by a stack of thin layers, in a manner known per se to those skilled in the art.

Claims (10)

1. Method for manufacturing a trim component (10) of a watch, a fashion item or an item of jewelry, characterized in that it comprises the following steps: – deposition of an opaque base layer (12) on all or part of the surface of an internal face (110) of a substrate (11) made of a transparent material, – localized ablation of the base layer (12) by laser machining, so as to form at least one pocket (14) whose bottom has a diffraction grating (15). 2. Method according to claim 1, in which the bottom of the pocket (14) is formed by the substrate (11) and/or by the base layer (12). 3. Method according to claim 1 or 2, in which several localized ablation steps are carried out so as to produce a plurality of diffraction gratings (15). 4. Method according to claims 1 to 3, comprising a polishing step carried out before the step of depositing the base layer (12), in which the internal face (110) of the substrate (11) is polished. 5. Method according to one of claims 1 to 4, comprising an etching step in which all or part of the base layer (12) is eliminated over its entire thickness without the internal face (110) of the substrate ( 11) is not impacted. 6. Method according to one of claims 1 to 4, comprising a step of depositing a secondary layer (13) in which an opaque secondary layer (13) is deposited at least on the diffraction grating (15). 7. Method according to claims 5 and 6, in which, during the etching step, a part of the secondary layer (13) is eliminated so as to conform said layer according to a predefined shape, without the internal face (110 ) of the substrate (11) is not impacted. 8. Manufacturing method according to one of claims 1 to 7, in which an anti-reflective coating is deposited on an external face (111) of the substrate (11) opposite the internal face (110). 9. Watch dial characterized in that it is formed by implementing the method according to one of claims 1 to 8. 10. Fashion item characterized in that it comprises a covering component (10) formed by implementing the method according to one of claims 1 to 8.