CH717123A2 - Method for metallic marking of a watch component. - Google Patents

Abstract

The present invention relates to a method for marking a timepiece component by means of an incident laser beam (6), of nanosecond or femtosecond type, arranged to pass through at least a portion (2) of the timepiece component having first and second faces. (18, 20) and made of a transparent material, the method comprising the steps of: arranging the portion (2) so that the incident laser beam (6) has an angle of incidence on the first face (18) substantially between 0 and 60 degrees, and in such a way that the portion (2) and the incident laser beam (6) can be moved relative to each other, position a metal substrate (22) near the second face (20), and controlling the incident laser beam (6) so that it has a focal plane located on the surface of the metal substrate (22), to give rise to a transfer of material from the latter to the portion (2).

Description

Technical area

The present invention relates to a method for marking a watch component by means of a first laser source arranged, in connection with an optical device, to define an incident laser beam intended to produce a marking on the watch component.

State of the art

[0002] Numerous methods of treating watch components by laser beam are already known from the state of the art.

[0003] Thus, for example, patent application EP 2825347A1 describes such a method making it possible to machine a watch component, more particularly to engrave it by means of a laser beam, the properties of which simultaneously make it possible to change the coloring of the component on the laser beam path.

[0004] Even if the method described in this patent application of the state of the art is also applicable to materials such as sapphire, the methods of this type are mainly intended to treat metallic watch components.

[0005] In general, most of the applications relating to the treatment of watch components by laser beam essentially aim at cutting or etching the material constituting all or part of the watch component.

Disclosure of the invention

A main aim of the present invention is to provide an alternative method to the methods of treatment of watch components by laser beam known from the prior art, the method according to the invention allowing the production of an original marking by laser beam on a watch component, and therefore the personalization of the latter with a high perceived quality.

[0007] To this end, the present invention relates more particularly to a method for marking a watch component of the type mentioned above, characterized in that the first incident laser beam is arranged to pass through at least a portion of the watch component, this portion having first and second opposite faces and being made of a material at least partially transparent to the incident laser beam, the method comprising the steps of: arranging the first face of the portion of the watch component relative to the incident laser beam of such so that the incident laser beam has an angle of incidence on the first face substantially between 0 and 60 degrees, and in such a way that the portion of the watch component and the incident laser beam can be moved relative to each other, position a metal substrate near the second face of the watch component portion, check the pr first laser source in such a way that it defines an incident laser beam composed of light pulses the duration of which is of the order of magnitude of a nanosecond or of a femtosecond, and having a focal plane located substantially on the surface of the metal substrate , so as to give rise to a transfer of material from the metal substrate to the second face of the portion of the timepiece component, and move the incident laser beam and the portion of the timepiece component relative to each other to produce a marking metallic on the second face of the portion of the watch component.

The portion to be treated can be directly a watch component as such or only a portion of a watch component, either made in one piece with the rest of the component, or attached to the rest of the component before or after the implementation of the method according to the invention, without departing from the scope of the latter.

[0009] Thanks to these characteristics, it is possible to produce a distinctive metallic marking on a watch component, at least a portion of which is at least partially transparent to the wavelength of the laser source used. The method according to the invention makes it possible to produce such a metallic marking with very precise control, therefore with good reproducibility and excellent resolution of the order of a few micrometers. The metallic marking may have the form of an extended continuous or discontinuous pattern, that is to say having portions separated from one another. It should also be noted that the method according to the present invention can be implemented without it being necessary to provide a protected enclosure during the laser treatment, in particular a vacuum enclosure, which is particularly advantageous from the point of view of handling of watch components to be processed.

In general, the method according to the invention may include an additional step consisting in treating the metal marking by means of a reprocessing laser beam defined from the first laser source or from a second laser source , in such a way that the reprocessing laser beam is composed of light pulses the duration of which is of the order of magnitude of a nanosecond and in such a way that the reprocessing laser beam is emitted in the direction of the second face, so at least partially sweeping away the metallic marking.

More specifically, the properties of the reprocessing laser beam can be adjusted such that its effect on the metallic marking gives the latter a metallic luster, or even a predefined coloring, possibly different from that of the starting metallic substrate.

It is thus possible to obtain a high level of personalization of the watch component processed by the method according to the invention.

In general, provision can be made for the incident laser beam to be composed of pulses having an average frequency of between 100 and 250kHz and, preferably, that it has an average power of less than 20Watts, more preferably less than 15Watts, again more preferably less than 10Watts.

In general, the portion of the watch component on which the metal marking is made can advantageously comprise glass or sapphire and, preferably, have a thickness, between its first and second faces, substantially between 0.1 and 3mm, more preferably between 0.4 and 2.5mm.

According to a preferred embodiment, provision can be made for the metal substrate to include one or more of the materials taken from the group comprising: steels, stainless steels, titanium, copper, brass, gold, platinum, tungsten.

In general, one can provide that the metal marking has a thickness substantially between 1 and 5 micrometers.

Advantageously, provision can be made for the metal substrate to be positioned at a maximum distance from the second face of the order of 500 micrometers, preferably of the order of 300 micrometers, during the implementation of the transfer of material from the metal substrate towards the portion to be treated of the watch component.

The present invention also relates to a timepiece component having a metallic marking obtained by implementing the method which has just been presented, as well as a timepiece comprising such a timepiece component.

Brief description of the drawings

Other characteristics and advantages of the present invention will emerge more clearly on reading the detailed description of a preferred embodiment which follows, made with reference to the accompanying drawings given by way of non-limiting example and in which : FIG. 1 represents a simplified block diagram of an exemplary implementation of a first step of a method for processing a timepiece component according to a preferred embodiment of the present invention, and FIG. 2 represents a simplified block diagram of an example of implementation of an additional step of the processing method of FIG. 1.

Mode (s) for carrying out the invention

[0020] FIG. 1 represents a simplified block diagram of an exemplary implementation of a first step of a method for processing a timepiece component according to a preferred embodiment of the present invention.

More specifically, the laser beam marking method according to the present invention aims to mark a portion 2 of a watch component (not shown in its entirety), this portion 2 being advantageously at least partially transparent at the wavelength of the laser beam used to carry out the marking. Thus, in general, the method according to the invention can be implemented in relation to all kinds of materials that are at least partially transparent in the visible light range, such as glass or sapphire by way of non-limiting illustration.

The portion 2 can be directly a watch component as such or only a portion of a watch component, either made in one piece with the rest of the component, or attached to the rest of the component, without going beyond the scope of invention. It is conceivable to use the portion 2 for authentication purposes of the timepiece in which the timepiece component is assembled.

[0023] Furthermore, provision can be made for the watch component to be directly visible on the corresponding timepiece, being located outside the box or inside but being visible through a glass, or it can be housed inside the box and not be at least partially visible until it is opened. As an alternative, it is also possible to provide that the watch component comprising the marking according to the invention is visible only after having removed one or more other components of the corresponding timepiece, without departing from the scope of the invention.

In general, to carry out the marking according to the invention, a first laser source 4agencée is used, in connection with an optical device, to define an incident laser beam 6destined to carry out the marking on the portion 2du watch component.

More specifically, the optical device may include, by way of non-limiting illustration, at least one first mirror 8 arranged at the output of the first laser source 4, the latter typically being able to be associated with a galvanometric head 10 comprising a set of additional mirrors, here shown diagrammatically in the form of two mirrors 12 and 14, making it possible to control the direction of propagation of the incident laser beam 6 and to cause the latter to scan in order to carry out the marking on the portion 2, according to the invention. The optical device also advantageously comprises a focusing device 16, shown schematically here in the form of a converging lens to define a desired focusing plane for the incident laser beam 6.

Advantageously, the first laser source 4 can be associated with the optical device directly inside a multi-axis numerical control machine.

The portion 2du horological component is shown schematically here in the form of a parallelepiped having first and second main faces 18 and 20, the first 18 is positioned so as to be arranged on the path of the incident laser beam 6.

The portion 2du watch component is arranged relative to the incident laser beam 6 such that the latter has an angle of incidence on its first face 18sensibly between 0 and 60 degrees, and in such a way that the portion 2 and the incident laser beam 6 can be moved relative to each other.

Thus, when a numerically controlled machine is used, it is advantageously programmed to control the incident laser beam 6 and its movements in an appropriate manner to carry out a marking of the portion 2 following a predefined path. The numerically controlled machine typically comprises a control device, for this purpose, taking into account the geometry of the portion 2 and of the marking to be produced, and defining the scanning speed of the surface to be treated by the incident laser beam 6 as well as the amplitude of movement of the beam and the generation of laser pulses, so as to obtain the desired marking. Advantageously, all of the marking of portion 2 can be carried out in a single operation.

Preferably, the portion 2 has a thickness, between its first and second faces 18 and 20, substantially between 0.1 and 3mm, preferably between 0.4 and 2.5mm.

A metal substrate 22 is positioned in the immediate vicinity of the second face 20 of the portion 2, that is to say after the portion 2 by following the optical path of the incident laser beam 6.

Preferably but not limited to, the metal substrate 22 comprises one or more of the materials taken from the group comprising: steels, stainless steels, titanium, copper, brass, gold, platinum, tungsten .

Furthermore, the metal substrate 22est preferably positioned at a maximum distance from the second face 20 of the order of 500 micrometers, preferably of the order of 300 micrometers.

Advantageously, the first laser source is chosen such that it defines an incident laser beam 6composed of light pulses whose duration is of the order of magnitude of a nanosecond or a femtosecond. In addition, the optical device is preferably arranged such that the incident laser beam 6 has a focal plane located substantially on the surface of the metal substrate 22, so as to give rise to a transfer of material from the metal substrate 22 to the second face 20 of the optical device. portion 2 of the watch component.

Typically, to treat metal substrates such as those mentioned above, we can choose a first laser source 4 such that the incident laser beam 6 is composed of pulses having an average frequency between 100 and 250 kHz, and such that the latter has an average power of less than 20Watts, preferably less than 15Watts, even more preferably less than 10Watts.

The number of pulses to be applied per mm <2> to produce a metal marking according to the invention depends in particular on the energy fluence of the laser beam used, on its frequency, on the scanning distance and on the scanning speed . Typically, the realization of a basic pattern on a watch component may require from 10 <4> to 10 <6> pulses per mm <2>, or from 10 <6> to 10 <8> pulses for a pattern of 1cm < 2>.

Thus, by the implementation of the above characteristics, one can achieve a metal marking having a thickness substantially between 1 and 5 micrometers.

Typically, the metallic marking thus obtained exhibits a dark, generally black, coloring.

[0039] Also, advantageously, there is provided an additional step of laser surface treatment of the metal marking produced according to the above description, as shown diagrammatically in FIG. 2. More specifically, it is preferably possible to provide that this additional processing step metallic marking makes it possible to modify its micro-structuring, at least on the surface, in particular so that it presents at least one metallic luster, or even so that its coloring is modified so as to present a new predefined coloring.

To achieve such colorations of the metal marking, it is subjected to the action of a laser with short or ultra-short pulse duration, preferably a laser source 24de defining nanosecond type, in association with an optical device not shown, a reprocessing laser beam 26, acting as a heat source which reacts with oxygen from the environment to coat the treated surface with a transparent or semi-transparent oxide layer. Depending on the parameters of the reprocessing laser beam 26 such as its power, frequency, pulse width, scanning speed, chopping frequency, number of repetitions or the distance between the treated surface and the focal plane of the beam reprocessing laser 26, among others, the oxide layer will have a certain thickness. Then illuminating the metal marking with white light, the radiation is reflected by the upper and lower oxide layers. Consequently, an interference phenomenon of the reflected rays is perceived by an observer as corresponding to a determined color.

When the first laser source 4 used is a nanosecond type source, this same laser source 4 can again be used to implement the additional step. When the first laser source 4 is of the femtosecond type, another laser source 24 of the nanosecond type should be used to implement the additional step.

In all cases, it is preferable to move the watch component between the production of the metal marking and the implementation of the additional step, such that the second face 20 of the portion 2 is directly exposed to the laser beam of 26 reprocessing of the metallic marking aimed at improving the appearance of the latter. Thus, the reprocessing laser beam 26 must be emitted in the direction of the second face 20 of the portion 2 of the watch component, so as to at least partially sweep the metallic marking, so that the appearance of at least part of the latter is modified. .

The implementation of the present invention is not limited to a timepiece component forming part of the casing of a timepiece. Indeed, any horological component can allow the implementation of the present invention, whether this is to confer a distinctive character on the horological component and therefore on the corresponding timepiece, or even whether it is for purposes of identification or authentication. Those skilled in the art will encounter no particular difficulty in adapting the present teaching to the manufacture of watch components for covering or for the watch movement. It may even be envisioned that the portion 2du timepiece component is visible only after removal of the timepiece component to increase the level of security in the identification or authentication of the corresponding timepiece.

The foregoing description attempts to describe a particular embodiment by way of nonlimiting illustration and the invention is not limited to the implementation of certain particular characteristics which have just been described, such as, for example, the nature of the watch component or the material in which it is made.

Claims (11)

1. A method of marking a watch component by means of a first laser source (4) arranged, in connection with an optical device, to define an incident laser beam (6) intended to carry out a marking on said watch component, characterized in that said first incident laser beam (6) is arranged to pass through at least a portion (2) of said watch component, said portion (2) having first and second faces (18, 20) opposite and being made of a material at less partially transparent to said incident laser beam (6), the method comprising the steps of: arranging said first face (18) of the portion (2) of the watch component relative to said incident laser beam (6) such that said incident laser beam (6) has an angle of incidence on said first face (18) substantially included between 0 and 60 degrees, and in such a way that said portion (2) and said incident laser beam (6) can be moved relative to each other, positioning a metal substrate (22) close to said second face (20) of the portion (2) of the watch component, controlling said first laser source (4) in such a way that it defines an incident laser beam (6) composed of light pulses the duration of which is of the order of magnitude of a nanosecond or of a femtosecond, and having a focal plane located substantially on the surface of said metallic substrate (22), so as to give rise to a transfer of material from said metallic substrate (22) to said second face (20) of the portion (2) of the timepiece component, and moving said incident laser beam (6) and said portion (2) of the timepiece component relative to one another to produce a metallic marking on said second face (20) of the portion (2) of the timepiece component. 2. Method according to claim 1, characterized in that it comprises an additional step consisting in treating said metal marking by means of a reprocessing laser beam (26) defined from said first laser source (4) or from a second laser source (24), such that said reprocessing laser beam (26) is composed of light pulses the duration of which is of the order of magnitude of a nanosecond and such that said laser beam of reprocessing (26) is emitted in the direction of said second face (20), so as to at least partially sweep said metallic marking. 3. Method according to claim 2, characterized in that the properties of said reprocessing laser beam (26) are adjusted such that its effect on said metallic marking gives the latter a metallic luster. 4. Method according to claim 2 or 3, characterized in that the properties of said reprocessing laser beam (26) are adjusted such that its effect on said metallic marking gives the latter a predefined coloration. 5. Method according to one of the preceding claims, characterized in that said incident laser beam (6) is composed of pulses having an average frequency between 100 and 250kHz. 6. Method according to one of the preceding claims, characterized in that said incident laser beam (6) has an average power less than 20Watts, preferably less than 15Watts, even more preferably less than 10Watts. 7. Method according to one of the preceding claims, characterized in that the portion (2) of said watch component on which said metallic marking is produced comprises glass or sapphire. 8. Method according to one of the preceding claims, characterized in that the portion (2) of said watch component on which said metal marking is produced has a thickness, between said first and second faces (18, 20), substantially between 0.1 and 3mm, preferably between 0.4 and 2.5mm. 9. Method according to one of the preceding claims, characterized in that said metal substrate (22) comprises one or more of the materials taken from the group comprising: steels, stainless steels, titanium, copper, brass, l 'gold, platinum, tungsten. 10. Method according to one of the preceding claims, characterized in that said metal marking has a thickness substantially between 1 and 5 micrometers. 11. Method according to one of the preceding claims, characterized in that said metal substrate (22) is positioned at a maximum distance from said second face (20) of the order of 500 micrometers, preferably of the order of 300 micrometers, when the implementation of said transfer of material from said metallic substrate (22) to said portion (2) of said watch component.