Method for laser treatment of timepiece components

Abstract

The invention relates to a method for laser treatment of a timepiece component (10), said method comprising an operation for treating a surface of said timepiece component (10) recorded in a standard orthogonal XYZ coordinate system, in which a laser (20) is controlled to emit a laser beam (21) and to move a focal point (210) of said laser beam (21), the invention relates to a method for scanning a surface to be processed (100) on a timepiece part (10) in response to a control command from a computer program, in order to follow a scanning strategy comprising a plurality of paths (31), each path having a component in a Z direction and a component in at least one of an X direction or a Y direction, the scanning strategy is defined such that the energy density emitted by the laser beam (21) varies across the surface (100) to be treated.

Description

Technical Field

[0001] This invention relates to the field of timepiece decoration.

[0002] More specifically, the present invention relates to a method for laser processing of watch components. For example, such components may consist of a dial, inlay, hands, plate, bar, oscillating weight, bezel, case centerpiece, or any other visible part of the watch. Background Technology

[0003] Laser processing methods for watch components have been known for many years. These laser processing methods make it possible to decorate the surfaces of these components, particularly by coloring or structuring them, or in other words by altering the state of the surface of the components, or even by removing material to create recesses, such as "Geneva grain." The laser processing methods can also be used to remove a layer from a surface.

[0004] To perform surface treatment, a laser is controlled to emit a series of laser beam pulses, moving the focus of the beam in a scanning plane relative to the surface to be treated, following a scanning strategy. This strategy depends on the surface treatment to be performed and takes into account various laser beam parameters, including the focal path.

[0005] When the surface to be processed has a complex geometry, for example, if it has a three-dimensional shape, the focus of the beam moves along a path perpendicular to the scanning plane between two consecutive pulse series, such that the pulse series is executed in separate scanning planes parallel to each other. In other words, with each pass, the focus moves, for example, a distance of about one micrometer in a direction perpendicular to the surface to be processed.

[0006] Therefore, at the micrometer scale, the treated surface has several steps of varying thicknesses forming shoulder 1, such as... Figure 1 As shown.

[0007] These shoulders 1 are a few micrometers high, for example, 5 micrometers. These shoulders 1 are difficult to see with the naked eye, but are clearly visible under a magnifying glass, and therefore are not suitable for watch parts intended for use in high-end watches.

[0008] Furthermore, decorative gradients, such as color gradients or texture gradients, are generated by scanning a laser beam, such that the scan produces multiple sets of impact points distributed according to different densities.

[0009] These impact points are visible to the naked eye and create a pixelated effect on the decoration, which is almost incompatible with high-end watches.

[0010] It is necessary to be able to perform laser processing on watch components to give them a suitable appearance at the micrometer scale. Summary of the Invention

[0011] Therefore, the present invention relates to a method for laser processing of a watch component, the method comprising operations for processing a surface of the watch component recorded in a standard orthogonal XYZ coordinate system, wherein a laser is controlled to emit a laser beam and move the focal point of the laser beam to impact the surface to be processed on the watch component in response to control instructions from a computer program, in order to follow a scanning strategy comprising multiple paths, each path having a component in the Z direction and a component in at least one of the X or Y directions, the scanning strategy being defined such that the energy density emitted by the laser beam varies across the entire surface to be processed.

[0012] The features of this invention enable the decoration of the surface to be treated on the substrate by producing decorative gradient effects (i.e., color gradients or texture gradients without pixelation or shouldering).

[0013] In certain embodiments, the invention may further include one or more of the following features, either individually or in any technically possible combination.

[0014] In certain embodiments, each path has a curved and / or straight shape.

[0015] In a particular embodiment, the processing operation is performed by a laser, which is composed of a CNC machine tool, which is formed by a frame and a working cover, and the clock component is disposed on an accessory in the working cover.

[0016] In a particular embodiment, the processing operation is performed to produce color on the surface to be processed, wherein a change in the energy density of the laser beam causes a gradual and direct change in the color of the surface to be processed.

[0017] In a particular embodiment, the processing operation is performed to produce a decoration by ablating one or more layers of material deposited on the substrate, wherein a change in the energy density of the laser beam causes a direct change in the thickness of the layer on the surface of the substrate.

[0018] In a particular embodiment, the surface to be treated is the surface of a metal layer with a thickness between 10 nm and 20 μm, and the processing operation is performed such that the thickness of the layer is reduced to a thickness equal to tens of nanometers or until the layer is removed.

[0019] In a particular embodiment, the surface to be treated is the surface of a thin layer of silicon oxide, titanium, aluminum, carbon-based material, chromium, gold, silver, aluminum, copper, or nickel deposited by PVD, CVD, or ALD, so as to have a thickness included between 10 nm and 500 nm, and the processing operation is performed to give the watch component an interference color gradient.

[0020] In a particular embodiment, the surface to be treated is the surface of a layer in a thin coating, the thin layer comprising a metal absorbing layer deposited on the substrate and a transparent layer made of oxide and deposited on the absorbing layer, the processing operation being performed to ablate the transparent layer to locally reduce its thickness, thereby locally altering the interference colors produced by the coating of the thin layer.

[0021] In a particular embodiment, the surface to be treated is the surface of a layer deposited by pulverization with a thickness between 3 μm and 150 μm.

[0022] In a particular embodiment, the surface to be processed is the surface of the substrate, and the processing operation is performed such that the surface is structured to produce a relief-like decoration with a uniform appearance at the micrometer scale, that is, without aliasing effect. Attached Figure Description

[0023] Other features and advantages of the invention will become apparent from the following detailed description, given by way of non-limiting example with reference to the accompanying drawings, in which: Figure 1 A surface that has been laser-treated using existing techniques is schematically shown, the surface having several steps of varying thicknesses forming shoulders.

[0024] Figure 2 A perspective view of a clock component in an XYZ coordinate system is schematically shown. The clock component has a surface to be processed by a laser processing method according to a preferred example of the invention, and a reference surface formed by multiple paths of the laser beam and the clock component relative to each other using a scanning strategy.

[0025] Figures 3a to 3c This indicates an example of a scanning strategy according to the method of the present invention.

[0026] Figure 4 and Figure 5 Two clock parts are shown, obtained using methods with different variations.

[0027] It should be noted that, for clarity, the accompanying drawings are not drawn to scale. Detailed Implementation

[0028] The present invention relates to a method for laser processing of a watch component 10. The watch component 10 includes a substrate 11, which is made of, for example, a metallic material (e.g., copper, steel, iron, aluminum, titanium, gold, silver or alloys thereof), a mineral material (e.g., ceramic, sapphire, aventurine, onyx), or an organic material (e.g., mother-of-pearl).

[0029] The method according to the invention uses a laser 20 comprising an optical system consisting of mirrors and lenses, through which a laser beam 21 is emitted from a laser source and passes. In a manner known to those skilled in the art, the optical system allows for the modification of, in particular, the energy, polarization, and size of the laser beam 21. Advantageously, the optical system also includes a light deflection device controlled by a known electronic control module. The laser beam 21 is emitted in pulses with durations on the order of nanoseconds, picoseconds, or femtoseconds.

[0030] The laser 20 used in this invention is a CNC machine tool consisting of a frame and a working housing. The laser beam 21 moves in response to control commands from a pre-programmed computer program, according to the decoration to be formed on the watch component 10. When using the method according to the invention, the watch component 10 is held in place on fittings disposed inside the working housing for this purpose.

[0031] All these aspects are well known to those skilled in the art and therefore will not be described in further detail herein. Instead, only information specific to this invention and different from conventional practices performed by those skilled in the art is described in detail herein.

[0032] The method includes operations for treating the surface of a watch component 10, wherein a laser 20 is controlled to emit a laser beam 21 to impact the surface 100 to be treated on the watch component 10. During the surface treatment operation, the focus 210 of the laser beam 21 is moved such that it passes through... Figures 3a to 3c The light deflection device shown is used to scan the surface 100 to be processed in order to follow a predetermined scanning strategy extending in three-dimensional space. Figures 2 to 3c As shown, the clock components are recorded in a standard orthogonal XYZ coordinate system and extend in the XY plane.

[0033] The scanning strategy includes multiple paths 31 in which a series of pulses from a laser beam 21 are continuously emitted, each pulse including a component in the Z direction and a component in at least one of the X or Y directions. For example, each path 31 has a curved and / or straight shape.

[0034] like Figure 2 As schematically shown in the perspective view, path 31 is recorded in a reference surface 30 extending in three-dimensional space in the XYZ coordinate system. The reference surface 30 has a different shape from the surface to be processed 100, such that the energy density emitted by the laser beam 21 varies across the entire surface to be processed 100.

[0035] Each path 31 corresponds to, for example: Figures 2 to 3cThe path of the laser beam 21 is shown, and in particular corresponds to the path of the focal point 210 of the laser beam 21 relative to the clockwork component 10, which is maintained in the proper position in the XYZ coordinate system by means of suitable fittings. Control of the movement of the focal point 210 is known to those skilled in the art.

[0036] Of course, the scanning strategy can limit the scanning of the laser beam 21 in several parallel directions or several non-parallel directions.

[0037] Prior to the surface treatment operation, a scanning strategy is defined in the step of programming the computer program. The scanning strategy is defined such that the energy density emitted by the laser beam 21 varies across the entire surface 100 to be treated. In particular, the scanning strategy depends primarily on the shape of the surface 100 to be treated on the decorative and watch component 10 to be produced; the closer the focal point 210 of the laser beam 21 is to the surface 100 to be treated, the greater the concentration of the laser beam 21 on the surface 100 to be treated, and therefore the greater the energy level exposed.

[0038] exist Figures 2 to 3c In this process, the surface to be treated 100 has a planar shape that extends only in the XY plane, but it can be any shape. Furthermore, the surface to be treated 100 may constitute part or all of the surface of the substrate 11 or the layer 12 deposited on the substrate 11.

[0039] For example, laser processing operations can be performed using laser beam parameters 21, resulting in decorations such as coloring of the substrate 11 or a layer 12 deposited on the substrate, ablation of one or more layers of material deposited on the substrate 11, structuring of the substrate 11, etc.

[0040] When the resulting decoration is a coloring of the substrate 11 or the layer 12 deposited on the substrate 11, depending on whether the surface to be treated 100 is the surface of the substrate 11 or the surface of the layer 12, the change in the energy density of the laser beam 21 causes a gradual and direct change in the color of the surface to be treated 100. In fact, the color of the surface to be treated 100 depends on its material and the energy level it is exposed to.

[0041] When the method according to the invention is used to produce decoration by ablation of at least one layer 12 deposited on a substrate 11, the change in energy density of the laser beam 21 causes a change in the surface of the substrate 11 (i.e., on the surface of the substrate 11). Figure 4 and Figure 5 The direct local variation in the thickness of layer 12 in the XY plane. Figure 4 and Figure 5 Two exemplary embodiments of the method are shown.

[0042] The layer or multiple layers on which the surface to be treated are located can be opaque, transparent or translucent, and can be deposited by any known method, such as electrodeposition, physical vapor deposition (PVD), chemical vapor deposition (CVD), atomic layer deposition (ALD), powdering, etc.

[0043] For example, the surface to be treated 100 can be a metal layer 12 composed of Au, Ag, Rh, Ru, Cu, Ni, or Cr, deposited, for example, by electrodeposition, and can have a thickness between 10 nm and 20 μm. Then, an optical effect is advantageously generated by the bevel formed by the thickness variation of layer 12, which is produced by the ablation of the layer; in particular, the incident light is reflected differently depending on the angle formed by the bevel and any portion unaffected by the laser treatment. Furthermore, the appearance of the watch component 10 can be matte on the laser-treated portion and glossy on the untreated portion of layer 12, or vice versa.

[0044] In this case, Figure 4 An example is schematically shown, where variations in thickness result in variations in the color of the clock component 10, as the color of the substrate 11 becomes more pronounced as the thickness of the layer 12 decreases. Processing operations can be performed to ablate the layer 12 to locally reduce its thickness until the thickness equals tens of nanometers or until the layer 12 is removed.

[0045] Of course, in a variation of this example, the surface to be treated 100 may be a coating consisting of at least two layers, an upper layer and a lower layer, and then a treatment operation is performed to ablate the upper layer to expose the lower layer, and if necessary, to ablate the lower layer to expose the substrate 11.

[0046] If one or more thin layers are deposited by PVD, CVD, or ALD, the thin layers can be made of silicon oxide, titanium, aluminum, carbon-based materials, chromium, gold, silver, aluminum, copper, nickel, etc. Advantageously, an interference effect can be produced, giving the clock component 10 a gradient of interference colors. In this case, the one or more thin layers have a thickness ranging from 10 nm to 500 nm.

[0047] For example, Figure 5 The watch component 10 shown has a thin coating layer comprising a metal absorbing layer 120, for example made of one of the aforementioned metals, deposited on a substrate 11, and a transparent layer 121, made of one of the aforementioned oxides, deposited on the absorbing layer 120. The transparent layer 121 is at least semi-transparent because it allows at least a portion of light radiation to pass through. The transparent layer 121 is ablated during the processing to locally reduce its thickness, such as... Figure 5 As shown, this is done to locally alter the interference colors produced by the thin coating layer.

[0048] When one or more layers 12 are deposited by powdering, the surface 100 to be treated may be made of a transparent or opaque resin, such as acrylic resin, polyurethane, polyepoxide, etc., and may or may not contain a colorant. In this case, one or more layers 12 have a thickness ranging from 3 μm to 150 μm.

[0049] In another exemplary embodiment of the method, a processing step is performed such that the surface to be processed 100 is the surface of the substrate 11. The surface of the substrate 11 is constructed to produce a decoration consisting of reliefs having a uniform appearance at the micrometer scale, that is, an appearance without overlap.

[0050] In a variation of this exemplary embodiment of the method, a processing step is performed to produce a roughness gradient in the substrate 11, which is a gradual change in the surface state of the substrate 11.

[0051] Generally, regardless of the surface area 100 to be treated, due to the features of this invention, the aesthetic appearance of the watch component 10 fully meets the requirements of high-end watches, provided that the treated surface does not exhibit any undesirable characteristics, such as... Figure 1 The schematic diagram illustrates the aliasing or pixelation phenomenon characterized by continuous shoulders.

[0052] More generally, it should be noted that the embodiments and uses considered above have been described by way of non-limiting examples, and other variations are therefore conceivable.

[0053] For example, the laser processing operation can be performed in several scans of the surface 100 to be processed according to a determined scanning step and a determined pulse overlap rate; these parameters are selected according to the decoration to be produced on the surface 100 to be processed, and therefore are not related to the present invention. This also applies to the power of the laser beam 21, the scanning speed of the surface 100 to be processed, the pulse duration, the wavelength of the laser beam 21, etc.

[0054] It should also be noted that the substrate 11 can be textured by polishing, sandblasting, shot blasting, micropolishing, sun brushing, stamping, brushing, satin finishing, engine turning, engraving, milling, wrapping, circular granulation or any other texturing operation before the surface treatment operation can begin.

Claims

1. A method for laser processing of a watch component (10), the method comprising operations for processing a surface of the watch component (10) recorded in a standard orthogonal XYZ coordinate system, wherein a laser (20) is controlled to emit a laser beam (21) and move the focal point (210) of the laser beam (21) to impact a surface (100) to be processed on the watch component (10) in response to control instructions from a computer program, in order to follow a scanning strategy comprising a plurality of paths (31), each path having a component in the Z direction and a component in at least one of the X or Y directions, the scanning strategy being defined such that the energy density emitted by the laser beam (21) varies over the entire surface (100) to be processed.

2. The method according to claim 1, wherein, Each of the paths (31) has a curved and / or straight shape.

3. The method according to claim 1 or 2, wherein, The processing operation is performed by a laser (20), which is composed of a CNC machine tool, which is formed by a frame and a working cover, and the clock component (10) is disposed on an accessory in the working cover.

4. The method according to any one of claims 1 to 3, wherein, The processing operation is performed to produce a color on the surface to be processed (100), and the change in the energy density of the laser beam (21) causes a gradual and direct change in the color of the surface to be processed (100).

5. The method according to any one of claims 1 to 3, wherein, The processing operation is performed to produce a decoration by ablation of one or more layers of material deposited on the substrate (11), wherein the change in the energy density of the laser beam (21) causes a direct change in the thickness of the layer (12) on the surface of the substrate (11).

6. The method according to claim 5, wherein, The surface to be treated (100) is the surface of a metal layer (12) with a thickness between 10 nm and 20 μm, and the processing operation is performed such that the thickness of the layer (12) is reduced to a thickness equal to tens of nanometers or until the layer (12) is removed.

7. The method according to claim 5, wherein, The surface to be processed (100) is a thin layer of silicon oxide, titanium, aluminum, carbon-based material, chromium, gold, silver, aluminum, copper or nickel deposited by PVD, CVD or ALD, so as to have a thickness between 10 nm and 500 nm, and the processing operation is performed so that the watch component (10) has an interference color gradient.

8. The method according to claim 7, wherein, The surface to be treated (100) is the surface of a layer in a thin coating, the thin layer comprising a metal absorbing layer (120) deposited on the substrate (11) and a transparent layer (121) made of oxide and deposited on the absorbing layer (120), the processing operation being performed to ablate the transparent layer (121) to locally reduce its thickness in order to locally change the interference color produced by the coating of the thin layer.

9. The method according to claim 5, wherein, The surface to be treated (100) is the surface of a layer (12) deposited by pulverization, wherein the thickness of the layer is between 3 μm and 150 μm.

10. The method according to claim 4, wherein, The surface to be processed (100) is the surface of the substrate (11), and the processing operation is performed to structure the surface to produce a relief-like decoration with a uniform appearance at the micrometer scale.

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