Timepiece with marker

Abstract

Timepiece (100) comprising at least one electrically conductive component providing the timepiece (100) with a given magnetic response upon exposure to a predetermined magnetic field variable over time, characterized in that the timepiece (100) comprises at least one marker (110) arranged to modify the given magnetic response of the timepiece (100), in order to provide the marked timepiece (100) with a specific and predetermined magnetic response.

Description

DESCRIPTION TITLE: Timepiece with marker Technical field of the invention

[0001] The present invention relates generally to watch parts, and in particular, the present invention relates to watch parts comprising a marker for the purposes of production control, maintenance, traceability, authentication. State of the art

[0002] It is known in the earlier art of watchmaking to include markers on timepieces for production control, maintenance, traceability, and authentication. However, these markers can affect the aesthetic appearance if they are visible, require disassembly if they are embedded within the timepiece, and necessitate specific and complex equipment if, for example, the markers are engravings that can only be read with specialized optical instruments. Description of the invention

[0003] One aim of the present invention is to address the disadvantages of the prior art mentioned above and in particular, first of all, to provide a timepiece comprising a marker for production control, maintenance, traceability, authentication purposes, and which is simple and / or reliable to manufacture and / or control, and / or trace, and / or authenticate.

[0004] For this purpose, a first aspect of the invention relates to a timepiece, comprising at least one electrically conductive component providing the timepiece with a given magnetic response to exposure to a predetermined and time-varying magnetic field, characterized in that the timepiece comprises at least one marker arranged to modify the given magnetic response of the timepiece, in order to provide the marked timepiece with a specific and predetermined magnetic response.

[0005] According to the implementation described above, the marker provides a specific and predetermined magnetic response to exposure to a time-varying magnetic field. Consequently, it is possible to distinguish a timepiece equipped with such a marker from one without. In other words, the presence of the marker in the timepiece guarantees a difference (typically compared to the same timepiece but without the marker) in the magnetic response during, or following, exposure to a time-varying magnetic field.

[0006] It is worth noting that the specific and predetermined magnetic response can be an absence of signal in response to exposure to a predetermined and time-varying magnetic field. Indeed, materials can be deliberately chosen that do not react to exposure to a predetermined and time-varying magnetic field. According to this implementation, the marker can be chosen so as not to disturb the predetermined and time-varying magnetic field, and this absence of disturbance constitutes the specific and predetermined magnetic response, that is, a particular signature.

[0007] The marker can be integrated into a specific manufacturing stage to verify that the timepiece has indeed undergone that particular stage. The marker's presence can be checked during a final manufacturing operation, or during maintenance or overhaul, to ensure the timepiece's conformity. A coding system using one or more markers can also be implemented, for example, to indicate the timepiece's origin (supplier, production line, etc.).

[0008] In other words, the marker is a marker that modifies the magnetic response of the timepiece, that is to say, it provides a signature particular magnetic field, and - which can be chosen or located so as not to affect the visual appearance of the timepiece, thus improving the perceived quality, - whose detection can be carried out simply by exposure to a time-varying magnetic field.

[0009] There are many possibilities for placing the marker in the timepiece, so the design is easier, because as mentioned above, there is no need to provide direct access for optical reading, nor to provide access or disassembly to access the marker.

[0010] Generally, a timepiece includes at least one electrically conductive component (this component may also be the marker), and exposure of this electrically conductive component to a time-varying magnetic field causes electric currents to flow through it, generating a magnetic field opposite to the applied magnetic field. The electrically conductive component, by modifying the applied magnetic field, thus determines a measurable magnetic response. The presence of the marker (a separate element or a local modification of a component) in the timepiece is intended to modify the magnetic response in such a way as to create a specific and predetermined or expected magnetic response.The presence of the marker then allows extremely reliable detection over time, the presence of the marker is resistant to the reviving operations typically carried out during after-sales service, the marker can be invisible, and / or impossible to replicate.

[0011] The timepiece may include the following characteristics, taken individually or in combination.

[0012] In one embodiment, the marker is formed, comprises, or is made of a paramagnetic material or a diamagnetic material. In another embodiment, the marker has a Relative magnetic permeability close to 1, typically between 0.9 and 1.1, between 0.95 and 1.05, or between 0.98 and 1.02. In one embodiment, the marker is formed, comprises, or is made of one or more non-magnetic materials, such as copper, aluminum, non-magnetic stainless steel, silicon, or plastic. In this embodiment, the marker does not have its own signature and / or its own response to exposure to a predetermined and time-varying magnetic field, but its presence is intended to measurably modify the response of the timepiece. In particular, it is not the marker's own signature and / or its own response to exposure to the predetermined and time-varying magnetic field that is measured, but its presence is intended to measurably modify the response of the manufactured part.

[0013] In one embodiment, the marker is formed, comprises, or is made of an electrically conductive material. In another embodiment, the marker has a high conductivity, for example, σ > 10 3 or o > 10 4 S / m. According to one embodiment, the marker is formed, comprises, or is made of a material such as copper, aluminum.

[0014] In one embodiment, the marker is formed, comprises, or is made of a material that is weakly or not at all conductive of electricity. In another embodiment, the marker has a low conductivity, for example, σ < 10⁻¹⁰ 3 or o < 10' 4 S / m. According to one embodiment, the marker is formed, comprises, or is made up of a material such as glass, ceramic, plastic, a metal oxide such as alumina, undoped silicon.

[0015] According to one embodiment, the marker is formed, comprises, or is made of a material that may be: - doped, to be electrically conductive and exhibit a high conductivity θ, for example θ > 10 3 or o > 10 4 S / m, or - weakly doped, to be a poor conductor of electricity and exhibit a relatively low conductivity θ, for example θ < 10 or θ < 10' 2 S / m. - undoped, to remain weakly or not at all conductive of electricity and to exhibit a low conductivity, for example, θ < 10' 3 or o < 10' 4 S / m. Thus, the same component, depending on its doping, may or may not conduct electricity and modify in a targeted way the response of the marked timepiece.

[0016] In one embodiment, the marker is not on the surface of the marked timepiece. In other words, the marker is not visible or accessible from the outside. In particular, the marker is not a component affixed to an external surface of the timepiece.

[0017] In one embodiment, the marker is not an RFID tag. In one embodiment, the marker does not include an electrical / electronic circuit. In one embodiment, the marker does not include a communication unit.

[0018] According to one embodiment, the marker provides the possibility of distinguishing the magnetic response, during or following exposure to a time-varying magnetic field, of a timepiece equipped with the marker from the magnetic response of a timepiece not equipped with the marker but having, for example, the same visual appearance and / or the same external dimensions, and / or the same mass, and / or the same technical characteristics as the timepiece equipped with the marker.

[0019] In one embodiment, the marker is formed by a single component or a single specific part of the timepiece. In another embodiment, the marker has a mass of less than 5%, preferably less than 2%, preferably less than 1% of the mass of the timepiece. In another embodiment, the marker has a volume of less than 5%, preferably less than 2%, preferably less than 1% of the volume of the timepiece.

[0020] According to one embodiment, the marker forms at least part of the electrically conductive component.

[0021] In one embodiment, the marker is an electrically insulating component arranged between two electrically conductive components. In another embodiment, the marker is an insulating component or a component forming insulation within the timepiece. In another embodiment, the marker is an insulating component or a component forming insulation and arranged between two electrically conductive parts of the timepiece. In one embodiment, the marker has a very low conductivity (σ (S / m)) (virtually zero, less than 10⁻¹⁰). 3 S / m, preferably less than 10' 6 S / m, preferably less than 10' 10 S / m) and / or a very high resistivity p (Qm) (greater than 10 6 Qm, preferably greater than 10 9 Qm, preferably greater than 10 12Qm). In one embodiment, the marker is an insulating or insulating component formed by a film or a surface treatment. In another embodiment, the marker is an insulating or insulating component sandwiched between two parts of the timepiece, for example, electrically conductive parts. In other words, the marker is an insulating or insulating component arranged within the timepiece to compartmentalize or modify a part or set of electrically conductive parts. In one embodiment, the marking consists of adding an insulating part (electrical insulator) between two conductive parts or adding an insulating surface treatment between contacting parts. This allows for modification of the current flow and therefore the signature during, or in response to, exposure to a changing magnetic field.In one embodiment, the marker is an electrically insulating component deposited on the surface of a functional or structural component of the timepiece. In another embodiment, the marker is an electrically insulating component deposited by a physical vapor deposition (PVD) process, a chemical vapor deposition (CVD) process, or an atomic thin-film deposition process. (ALD). For example, the marker is a thin film of alumina, with a thickness that can be about 5 nm, about 10 nm and / or can be on the order of a tenth of a micron or on the order of a micron.

[0022] In one embodiment, the marker is a layered compound with a plurality of layers, each having a specific electrical conductivity or magnetic permeability, preferably different from that(s) of the other layers. In another embodiment, the marker formed by a layered compound comprises at least one electrically insulating layer arranged between two electrically conductive layers.

[0023] In one embodiment, the marker is a magnet and / or a component that exhibits remanent magnetization. This allows the signature to be modified during, or in response to, exposure to the varying magnetic field.

[0024] In one embodiment, the marker is included in a functional component of the timepiece, such as a case, an automatic movement rotor, a case back, or a watch strap. Thus, there is no need to add a specific component: the marker is directly integrated into an existing component of the timepiece that provides a particular function.

[0025] In general, the functional component in the timepiece provides at least one primary function, for example an assembly function, a chronometry function, a sealing function, a display function, a movement transmission function, a striking function, an energy storage function, a decorative function...

[0026] In one embodiment, the marker also forms a visual marking. One can consider an engraving that removes a specific amount of material to provide a specific magnetic response. Another can consider a marking with an ink comprising a compound that reacts to exposure to a time-varying magnetic field. For example, one can choose an ink with a compound that provides a specific magnetic response; one can plan to write certain characters of a word with this ink and other characters of the word with an ink that does not react, or reacts differently.

[0027] In one embodiment, the marker is a recess formed in the functional component. This may include a cavity (open or closed), a hole (through, closed, etc.), or one or more pores. In one embodiment, the recess has a characteristic dimension (diameter, depth, length, width) greater than 0.05 mm, preferably greater than 0.1 mm, preferably greater than 0.25 mm, preferably greater than 0.5 mm, preferably greater than 0.75 mm, preferably greater than 1 mm, and / or less than 2 mm, preferably less than 1.75 mm, preferably less than 1.5 mm, preferably less than 1.25 mm, preferably less than 1 mm, preferably less than 0.75 mm.

[0028] In one embodiment, the marker is an insert formed within the functional component. In this embodiment, the marker is an insert, that is to say, an added component that is different / distinct from the component on or in which it is embedded, particularly in terms of material. In one embodiment, the insert has a characteristic dimension (diameter, depth, length, width, overall dimension) greater than 0.05 mm, preferably greater than 0.1 mm, preferably greater than 0.25 mm, preferably greater than 0.5 mm, preferably greater than 0.75 mm, preferably greater than 1 mm, and / or less than 2 mm, preferably less than 1.75 mm, preferably less than 1.5 mm, preferably less than 1.25 mm, preferably less than 1 mm, preferably less than 0.75 mm.

[0029] In one embodiment, the marker forms a specific and / or non-functional component of the timepiece. In this embodiment, the marker is an added component that is different from / distinct from the components of the timepiece. According to this embodiment, the marker forms a specific and / or non-functional component of the timepiece which has only one function of making the magnetic response specific and predetermined.

[0030] In one embodiment, the marker is a specific and / or non-functional component attached to a functional component of the timepiece, such as a case, an automatic movement rotor, a case back, a watch strap, or a decorative element inside or outside the timepiece. It may be a surface coating, a surface treatment, or a film applied to a functional component of the timepiece. It may also be a pin or a screw with no assembly function. Alternatively, it may be a marker forming a raised or continuous component of a functional component of the timepiece.In one embodiment, the marker can be a physical element distinct from the rest of the component, a marking, a local modification of the material, a doping agent, an additional layer (deposited by PVD, for example), or a geometric modification of the component to obtain a specific response. In another embodiment, it is possible to substitute one element of a group with another element possessing different properties to provide a specific magnetic response, but with an appearance identical to the other elements of the group. For example, one could choose one of the movement bridges, one of the screws of the timepiece, or even one of the movement jewels, a dial appliqué, or one of the pushers or crowns of a timepiece.

[0031] The term "timepiece" encompasses all types of watches, watch parts, and watch components. A watch is defined as a timekeeping instrument designed to be worn and function in all positions, as defined by ISO TC 114. A watch comprises several watch parts, such as the movement, The case, the bracelet, and the dial with the hands. A watch component typically consists of an assembly of several watch parts. For example, a watch bracelet is an assembly of bracelet links, a clasp, a fastener, and other components. For example, a dial is an assembly of a dial plate, which may include decorations, hour markers, fasteners, and other components. For example, a movement is an assembly of a mainplate, bridges, springs such as a balance spring and a mainspring, a winding rotor, moving parts, and other components. Watch accessories are items related to watches, such as a certificate or warranty card, a warranty seal, a watch box, and watch accessories such as cufflinks, pens, lighters, and the like, which may be sold with the watch.The term "timepiece" also includes jewelry or precious metal pieces.

[0032] In one embodiment, the marker is formed by a modification, for example a local one, of the material of a component of the timepiece. This local modification could be achieved, for example, by a localized laser treatment, and / or a localized ion implantation, and / or a localized deposition of a layer followed by a diffusion heat treatment, and / or a localized carburizing / nitriding / oxidizing treatment, and / or combinations thereof. In other words, the marker is a functional or structural component of the timepiece whose physical or material characteristic has been modified, either globally or locally. It should be noted that, in one embodiment, this modification does not affect the dimensions of the functional or structural component of the timepiece.It can be noted that, according to one embodiment, this modification does not affect the external appearance of the functional or structural component of the timepiece.

[0033] According to the embodiment above, the local modification of the material is carried out in order to modify the electrical properties and / or magnetic properties of a component of the timepiece, for example by inducing a phase change, a modification of the crystalline structure, or a change in chemical composition. Thus, the magnetic response of a timepiece equipped with the marker will be different from the same timepiece without the marker, due to the imposed change in the electrical and / or magnetic properties of a component of the timepiece.

[0034] According to one embodiment: - the functional component is formed with a first material having at least one predetermined magnetic characteristic or one predetermined electrical characteristic, - The marker is formed with a second material having at least one second predetermined magnetic characteristic or a second predetermined electrical characteristic, different respectively from the first predetermined magnetic characteristic or the first predetermined electrical characteristic. Thus, the difference in magnetic or electrical properties is intended to generate a specific and predetermined measurable magnetic response, allowing the presence of the marker to be determined.

[0035] According to one embodiment: - the functional component is formed with a first material having at least a first predetermined magnetic permeability or a first predetermined electrical conductivity, - the marker is formed with a second material having at least a second predetermined magnetic permeability or a second predetermined electrical conductivity, different by at least 50% respectively from the first predetermined magnetic permeability or the first predetermined electrical conductivity.

[0036] According to one embodiment, the marker: - is metallic, and / or - is a metallic portion of a watch component that has undergone a predetermined surface treatment or heat treatment, or a local modification of the material, and / or - includes an electrical coil, and / or - exhibits a Curie temperature between 250 K and 400 K.

[0037] For example, a specific heat treatment can be applied to an entire component of the timepiece. For instance, annealing between 500°C and 1200°C can be performed on a component made of a material such as FeCo, FeNi, or FeSi. This will significantly and permanently alter the magnetic properties of this component at room temperature. Once this heat treatment has been completed, the component becomes a marker and remains geometrically identical in every respect to the same component without heat treatment.

[0038] For example, a specific electrical coil can be provided for marking, in addition to an electrical coil for a Lavet motor of a quartz movement for example.

[0039] For example, one could consider making the marker with a magnetocaloric material, such as gadolinium, which has a magnetic behavior that changes significantly with temperature. Below a temperature point defined by the material's physical properties (the Curie point), it behaves like a ferromagnetic material, meaning it easily conducts and channels magnetic field lines. Above the Curie temperature, the material behaves paramagnetically, allowing field lines to pass through without influencing them, like air. The Curie point of gadolinium is approximately 20°C. With a marker made of this material, the magnetic response will differ depending on whether the measurement is taken at 10°C or 30°C. In other words, depending on the specific embodiment, the marker exhibits variable magnetic permeability or electrical conductivity. of the temperature. Thus, it is possible to predict how the magnetic response of the timepiece can be modified in a particular way depending on the temperature.

[0040] A combination of "metallic / non-metallic" or "electrically conductive / non-electrically conductive" materials can be used to pair the marker with a specific component of the timepiece that houses the marker. For example, one component and marker could be made of an electrically conductive material, while the other could be made of a non-conductive material (such as a ceramic). Alternatively, one component and marker could be made of a metallic material, while the other could be made of a non-metallic material (such as a ceramic). As an example, a ceramic case could house a metallic marker, or vice versa.

[0041] In one embodiment, the timepiece comprises a plurality of markers, each arranged to modify the given magnetic response of the timepiece, in order to provide the marked timepiece with a specific and predetermined magnetic response. In other words, one can provide a coding of the timepiece or a local marking.

[0042] According to one embodiment, at least two markers are formed in different materials, so that each specifically modifies the given magnetic response of the timepiece, in order to provide the marked timepiece with a specific and predetermined magnetic response.

[0043] According to one embodiment, at least two markers are arranged at specific and different positions on the timepiece, so that each marker specifically and locally modifies the given magnetic response of the timepiece, in order to provide the timepiece of watchmaking marked at least two specific, predetermined and local magnetic responses.

[0044] According to one embodiment, the plurality of markers is arranged in the timepiece so as to provide authentication coding with the specific and predetermined magnetic response.

[0045] According to one embodiment, a method for controlling a timepiece can be provided, comprising at least one marker arranged to modify the given magnetic response of the timepiece, the control method comprising a control phase with the steps of: - to place the timepiece, or at least a part of the timepiece, in a predetermined relative position with respect to at least one source of magnetic field and / or with respect to at least one magnetic field measuring device, - exposing the timepiece, or at least a part of the timepiece, to at least one predetermined and time-varying magnetic field generated by the magnetic field source, - to measure, using at least one magnetic field measuring device, at least one characteristic of the magnetic field in the vicinity of the timepiece exposed to the predetermined magnetic field which varies over time, - to deduce a magnetic response of the timepiece from the measured characteristic of the magnetic field in the vicinity of the timepiece, - compare the magnetic response of the timepiece to a reference magnetic response.

[0046] According to the implementation described above, the testing method includes a step of exposing the timepiece to at least one predetermined magnetic field that varies over time. The applicant was surprised to find that such exposure to Variable magnetic fields, particularly low-amplitude variable magnetic fields, did not disrupt the operation of the timepiece (no stops or operational disruptions were observed). Furthermore, measuring at least one characteristic of the magnetic field in the vicinity of the timepiece containing the marker allows for the deduction of a response from the timepiece that can be compared to a reference magnetic response. This allows for the control, measurement, or authentication of the timepiece containing the marker, particularly by: - verifying / checking the similarity of the response of the timepiece containing the marker with a reference magnetic response, and / or - measuring a difference in the response of the timepiece including the marker with the reference magnetic response, - comparing the response of the timepiece containing the marker with templates built around the reference magnetic response... Thus, the timepiece containing the marker can be checked, measured or authenticated quickly, without affecting its operation, and without necessarily having to disassemble it.

[0047] More generally, a method for controlling a timepiece can be envisaged comprising at least one marker arranged to modify the given magnetic response of the timepiece, or a marker arranged to modify the given magnetic response of the timepiece, the control method comprising a control phase with the steps consisting of: - place the timepiece containing the marker, or the marker of the timepiece, at a predetermined relative position with respect to at least one magnetic field source and / or with respect to at least one magnetic field measuring device, - expose the timepiece containing the marker, or the marker of the timepiece, to at least one predetermined and time-varying magnetic field generated by the magnetic field source, - to measure, using at least one magnetic field measuring device, at least one characteristic of the magnetic field in the vicinity of the timepiece containing the marker, or of the marker of the timepiece, exposed to the predetermined magnetic field which varies over time, - to deduce a magnetic response of the timepiece including the marker, or of the marker of the timepiece, from the measured characteristic of the magnetic field in the vicinity of the timepiece, or of the component of the timepiece, - compare the magnetic response of the timepiece containing the marker, or of the marker of the timepiece, to a reference magnetic response.

[0048] In particular, the invention may relate to a method for inspecting a timepiece, which may include at least one marker arranged to modify the given magnetic response of the timepiece, the inspection method comprising the steps of: - to place the timepiece, or at least a part of the timepiece, in a predetermined relative position with respect to at least one source of magnetic field and / or with respect to at least one magnetic field measuring device, - exposing the timepiece, or at least a part of the timepiece, to at least one predetermined and time-varying magnetic field generated by the magnetic field source, - to measure, using at least one magnetic field measuring device, at least one characteristic of the magnetic field in the vicinity of the timepiece exposed to the predetermined magnetic field which varies over time, - to deduce a magnetic response of the timepiece from the measured characteristic of the magnetic field in the vicinity of the timepiece, - compare the magnetic response of the timepiece to a response magnetic reference to check / control if the timepiece includes the marker.

[0049] According to one embodiment, during the step of exposing the timepiece to a predetermined and time-varying magnetic field, at least: - an amplitude, and / or - a frequency, and / or - an orientation, and / or - A spatial gradient of the magnetic field generated by the magnetic field source is modified or variable over time. As seen above, exposing a timepiece containing a marker to such a time-varying magnetic field does not impair the timepiece's operation.

[0050] According to one embodiment, during the exposure step of the timepiece comprising a marker to a predetermined and time-varying magnetic field, the frequency of the predetermined magnetic field is within a frequency range from 10 Hz to 10 7 Hz.

[0051] According to one embodiment, during the stage of exposing the timepiece comprising a marker to a predetermined magnetic field that varies over time, the amplitude of the predetermined magnetic field is modified over time to obtain a powerful magnetic field, preferably according to a sinusoidal function.

[0052] According to one embodiment, during the exposure step of the timepiece comprising a marker to a predetermined magnetic field that varies over time, the amplitude of the predetermined magnetic field is within a range of values ​​from 0 T to 5.10-1 T and preferably within a value range from 0 T to 6.10 -3 T, and preferably within a value range from 0 T to 10' 3 T.

[0053] In one embodiment, during the step of exposing the timepiece containing a marker to a predetermined magnetic field that varies over time, a relative movement is imposed between the timepiece containing the marker and the magnetic field source. This relative movement allows the timepiece containing the marker to be exposed to a varying magnetic field, even if the magnetic field source generates a constant or fixed magnetic field.

[0054] According to one embodiment, during the exposure step of the timepiece comprising a marker to a predetermined and time-varying magnetic field, the orientation of the predetermined magnetic field varies by at least 10°, and preferably by at least 30°, relative to an initial orientation of the predetermined magnetic field. It is possible to generate a rotating magnetic field, even over a limited angular sector, for example, less than 360°.

[0055] According to one embodiment, during the exposure step of the timepiece comprising a marker to a predetermined and time-varying magnetic field, the orientation of the predetermined magnetic field varies cyclically, and for example the orientation of the predetermined magnetic field varies to impose a rotating magnetic field, for example at a frequency of at least 50 revolutions per second, and preferably at least 5 x 10⁻¹². 2 revolutions per second.

[0056] According to one embodiment, the step of exposing the timepiece comprising a marker to a predetermined magnetic field that varies over time includes a step of electrically supplying at least one electric coil, or even at least two electric coils simultaneously or with a time offset (if, for example, the timepiece includes at least two distinct markers).

[0057] According to one embodiment, the step of measuring at least one characteristic of the magnetic field in the vicinity of the part watchmaking including a marker includes the measurement: - of an amplitude and / or orientation of the magnetic field, and / or - of a current induced in a coil, and / or - of a voltage induced in a coil.

[0058] According to one embodiment, the step of measuring at least one characteristic of the magnetic field in the vicinity of the timepiece comprising a marker is carried out: - by at least one magnetic field sensor, and / or - by at least one electrical coil, called the receiving coil, preferably by at least one coil of the magnetic field source, called the transmitting and receiving coil, used to generate the predetermined magnetic field, which varies over time. The use of a transmitting and receiving coil allows for a simple measuring device with a limited number of components.

[0059] According to one embodiment, the step of deducing the magnetic response of the timepiece comprising a marker includes: - a comparison between a value of a magnetic field characteristic measured without the timepiece, and a value of the magnetic field characteristic measured in the vicinity of the timepiece including a marker, and / or - a calculation of the phase shift between the generated magnetic field and a value of the magnetic field characteristic measured in the vicinity of the timepiece containing a marker, - an analysis phase involving the construction of a Bode plot, and / or a Nyquist plot, and / or a Fourier series decomposition. Placing the timepiece in a varying magnetic field alters the distribution and amplitude of the magnetic field within and around the timepiece, which includes a marker. This magnetic field The resulting modified signal is measured and analyzed to deduce the magnetic response of the timepiece containing a marker.

[0060] According to one embodiment, the control method includes an initial baseline phase with the steps of: - to place a reference timepiece (including a reference marker) at the predetermined relative position with respect to said at least one magnetic field source and with respect to said at least one magnetic field measuring device, - expose the reference timepiece to at least one predetermined and time-varying magnetic field generated by the magnetic field source, - measure at least one characteristic of the magnetic field in the vicinity of the reference timepiece exposed to the predetermined magnetic field, which varies over time, - to deduce a magnetic response of the reference timepiece from the measured characteristic of the magnetic field in the vicinity of the timepiece, - record the magnetic response of the reference timepiece.

[0061] In one embodiment, the step of placing the timepiece comprising a marker at a predetermined relative position with respect to at least one magnetic field source and with respect to at least one magnetic field measuring device includes a step of placing the timepiece comprising a marker in a fixture and / or clamping the timepiece comprising a marker in a fixture, and / or mechanically abutting the timepiece comprising a marker against or within a fixture. In one embodiment, the steps of placing the timepiece comprising a marker in a fixture and / or clamping the timepiece comprising a marker in a fixture, and / or mechanically abutting the timepiece comprising a marker against or within a fixture are The measurements were performed by bringing the timepiece containing a marker into contact or against a stop with a portion of the positioning element of said marker and at least one magnetic field source. Thus, the relative position between the timepiece containing the marker and the magnetic field source and / or the measuring device is reproducible, reliable, and robust.

[0062] According to one embodiment, the step of placing the timepiece comprising a marker at a predetermined relative position with respect to at least one magnetic field source and with respect to at least one magnetic field measuring device includes a step of placing the timepiece comprising a marker less than 10 mm, preferably less than 7 mm, preferably less than 5 mm, preferably less than 2 mm, preferably less than 1 mm, with respect to at least one magnetic field source and / or with respect to at least one magnetic field measuring device, and most preferably, the timepiece comprising a marker is placed in contact with said at least one magnetic field source and / or with said at least one magnetic field measuring device.Thus, the timepiece containing a marker is well exposed to the magnetic field (as is the marker), and / or is located near the measuring device, which guarantees reliable measurements, with a good signal / noise ratio.

[0063] According to one embodiment, the step of exposing the timepiece including a marker to a predetermined and time-varying magnetic field generated by the magnetic field source, and / or the step of measuring at least one characteristic of the magnetic field in the vicinity of the timepiece including a marker exposed to the predetermined and time-varying magnetic field are carried out at least partially simultaneously.

[0064] According to one embodiment, the step of exposing the timepiece containing a marker to a magnetic field predetermined and variable over time generated by the magnetic field source, and the step of measuring at least one characteristic of the magnetic field in the vicinity of the timepiece comprising a marker exposed to the predetermined and variable over time magnetic field are carried out over a period of less than 2 minutes, preferably less than 1 minute, preferably less than 10 s, preferably less than 7 s, preferably less than 5 s, preferably less than 3 s.

[0065] According to one embodiment, the step of exposing the timepiece comprising a marker to a predetermined and time-varying magnetic field generated by the magnetic field source includes: - a first control step consisting of exposing a first portion of the timepiece, including for example a first marker, to a first predetermined magnetic field that varies over time, generated by the magnetic field source, - A second control step involves exposing a second portion of the timepiece, including, for example, a second marker, to a second predetermined magnetic field that varies over time, generated by the magnetic field source. This allows for the control, measurement, and authentication of distinct parts of the same timepiece containing one or more markers. It is even possible to reconstruct a code by placing markers at predetermined locations on the timepiece. The presence of a marker can represent a "1" in a binary code, and its absence can represent a "0".

[0066] In one embodiment, the inspection method is a control method implemented after a specific manufacturing operation of the timepiece, including a marker. An assembly operation can be used to verify that all components are present and / or arranged in the correct position. Alternatively, a "new" inspection can be performed immediately after manufacturing to record the results. the response so that it can be compared when returning to the maintenance workshop, even several years later.

[0067] In one embodiment, the control method constitutes a method for authenticating the timepiece, including a marker, implemented, for example, during or prior to a maintenance operation. In another embodiment, the authentication method includes an initial signature creation phase before delivery, comprising steps, implemented, for example, during a final manufacturing inspection, consisting of: - to place the new timepiece, including a marker, at the predetermined relative position with respect to at least one magnetic field source and with respect to at least one magnetic field measuring device, - expose the new timepiece, including a marker, to at least one predetermined and time-varying magnetic field generated by the magnetic field source, - measure at least one characteristic of the magnetic field in the vicinity of the new timepiece, including a marker exposed to a predetermined magnetic field that varies over time, - deduce a magnetic response of the new timepiece containing a marker from the measured characteristic of the magnetic field in the vicinity of the new timepiece containing a marker, - record the magnetic response of the new timepiece and including a marker as a reference magnetic response.

[0068] According to one embodiment, the magnetic response of the new timepiece including a marker forms a reference signature, and / or the magnetic response of the timepiece to be checked forms a signature of the timepiece including a marker.

[0069] According to one embodiment, the control method includes a final phase comprising the steps of: - quantify the difference between the magnetic response of the timepiece containing a marker and the reference magnetic response, and / or - compare, with a predetermined threshold, the difference between the magnetic response of the timepiece containing a marker and the reference magnetic response, and / or - qualify the timepiece including a controlled marker as a compliant timepiece or an authentic timepiece, in particular if a difference between the magnetic response of the timepiece including a marker and the reference magnetic response is less than a predetermined threshold and / or is acceptable.

[0070] According to one embodiment, during the exposure step of the timepiece comprising a marker to a predetermined magnetic field that varies over time, at least: - an amplitude, and / or - a frequency, and / or - an orientation, and / or - a spatial gradient of the magnetic field generated by the magnetic field source exhibits a non-zero time derivative for at least 10 ns, preferably at least 100 ns, preferably at least 1 ps, preferably at least 100 ps, ​​preferably at least 1 ms, preferably at least 1 s, preferably at least 10 s, preferably at least 1 minute. However, it is not excluded to provide time intervals during which the magnetic field does not vary, although preferably the magnetic field varies throughout the exposure to the magnetic field.

[0071] According to one embodiment, the magnetic field source comprises at least one magnet, such as a permanent magnet, and the step of exposing the timepiece to at least one predetermined and time-varying magnetic field generated by the magnetic field source includes a step of imposing at least one relative motion between the magnetic field source and the timepiece including a marker.

[0072] According to one embodiment, said field includes at least one predetermined and time-varying magnetic field whose amplitude exhibits a sinusoidal, rectangular, triangular, jump, pseudorandom binary sequence (PRBS), and / or multifrequency signal (sum of several sinusoids of different chosen frequencies). It should be noted that the electric current generating the predetermined and time-varying magnetic field also exhibits this sinusoidal, rectangular, etc., temporal waveform.

[0073] According to one embodiment, the measurement can be made by gradually varying the frequency, for example, a measurement at a first frequency fi for a certain duration (a few periods), a measurement at a second frequency f2 for a certain time (a few periods), etc.

[0074] According to one embodiment, it is possible to plan to make the measurement with a multi-frequency signal (which includes a sinusoid of first frequency fi and amplitude ai, a sinusoid of second frequency f2 and amplitude a2, a sinusoid of third frequency fs and amplitude as, etc.) which allows the test to be done quickly, with a single signal which includes the different desired frequencies. Description of the figures

[0075] Other features and advantages of the present invention will become more apparent upon reading the following detailed description of embodiment(s) of the invention given by way of non-limiting example(s) and illustrated by the accompanying drawings, in which:

[0076] [fig. 1] schematically represents at a given instant field lines of a variable magnetic field generated by a transmitting coil with a first frequency;

[0077] [fig. 2] schematically represents the field lines of the variable magnetic field generated by the emitting coil, when a timepiece is placed near the emitting coil;

[0078] [fig. 3] schematically represents the field lines of the variable magnetic field generated by the emitting coil with a second frequency, when the timepiece is always placed near the emitting coil;

[0079] [fig. 4] schematically represents a timepiece similar to the timepiece in figures 2 and 3, comprising a marker intended to provide the marked timepiece with a specific and predetermined magnetic response;

[0080] [fig. 5] represents the timepiece comprising a marker of figure 4, installed near a source of magnetic field and a measuring device together forming a first variant of a control device for measuring a magnetic response of the timepiece to exposure to a variable magnetic field;

[0081] [fig. 6] represents the timepiece including a marker of figure 4, installed near a second variant of a control device to measure a magnetic response of the timepiece to exposure to a varying magnetic field;

[0082] [fig. 7] represents a variant of the timepiece including a marker of figure 4, installed near a third variant of a control device to measure a magnetic response of the variant of the timepiece including a marker to exposure to a varying magnetic field;

[0083] [fig. 8] generally represents concrete implementation variants of the magnetic field source, to expose the timepiece including a marker to a variable magnetic field;

[0084] [fig. 9] represents a graph showing magnetic responses of several watch parts, measured with the control method implemented by the control device in figure 5 for example;

[0085] [fig. 10] represents a graph showing an example of a variable signal that can be used when implementing this control method;

[0086] [fig. 11] represents in the upper part a graph of the magnetic responses of two components or watch parts of identical external appearance and represented in the lower part. One of the watch parts includes an internal housing (or inlay) with a marker made of ferromagnetic metal;

[0087] [fig. 12] represents in the upper part a graph of the magnetic responses of two watch parts including screws shown in the lower part. One of the watch parts includes so-called standard screws, and the other of the watch parts includes screws with a localized surface treatment to form a marker;

[0088] [Fig. 13] shows in its upper part a graph of the magnetic responses of three timepieces comprising internal components of the same dimensions, shown in the lower part. The first timepiece includes a first internal component with a first surface treatment, the second timepiece includes a second internal component with a second surface treatment, and the third timepiece includes a third internal component with a third surface treatment.

[0089] Detailed description of implementation method(s)

[0090] Figure 1 schematically represents, at a given instant, the field lines of a varying magnetic field generated by a transmitting coil 10 with a first frequency. In the example given, the transmitting coil 10 is static, and the transmitting coil 10 is supplied with a varying electric current. Figure 1 represents the distribution of the field lines at a given instant. In the case shown, the coil is circular with a square cross-section. The model or distribution of the field lines: - is axisymmetric around the vertical axis of the coil in figure 1; - is symmetric with respect to a plane parallel to the upper or lower face of the transmitting coil 10 and which passes through the center of the transmitting coil 10. In the case of Figure 1, and for the rest of the disclosure, Figure 1 represents a transmitting coil 10 alone, but a core or a frame, for example, made of a material with high magnetic permeability (for example, a ferromagnetic material) can be provided to direct or concentrate the magnetic field lines in a particular way.

[0091] Figure 2 schematically represents the field lines of the varying magnetic field generated by the transmitting coil 10 when a timepiece 100 (represented by dashed lines in Figure 2) is placed near the transmitting coil 10. In the example given, and as in the example in Figure 1, the transmitting coil 10 is always stationary, and it is supplied with a varying electric current (typically an alternating current, for example, a sinusoidal or square wave current). Figure 2 shows the distribution of the field lines at a given instant. It can be noted that the timepiece 100 significantly alters the distribution of field lines compared to the case in Figure 1.

[0092] As is well known, a magnetic field, whose amplitude varies over time, induces electrical voltages in any material A conductor placed in this field (typically a component of the timepiece shown in Figure 2 or 3) induces these voltages, causing the formation of induced current loops, called eddy currents, whose direction is determined by Lenz's law. According to Lenz's law, the direction of the induced current is such that, through its effects, it opposes the cause that generated it. Eddy currents therefore flow in a direction that creates a field opposite to the field that produced them, thus altering the distribution of the magnetic field.

[0093] We can therefore observe in Figure 2 that the magnetic field, generated by the transmitting coil 10 at the first frequency, has field lines that are modified compared to the field lines in Figure 1. In particular, we can note the presence of field lines within the timepiece 100 itself, at a first depth P1 relative to the bottom of the case of the timepiece 100.

[0094] Figure 3 schematically represents the field lines of the variable magnetic field generated by the transmitting coil 10 with a second frequency, when the timepiece 100 (represented in dotted lines) is always placed near the transmitting coil 10.

[0095] In the example given in Figure 3, the transmitting coil 10 is supplied with a variable electric current (an alternating current such as a sinusoidal or square wave current) having a second frequency, and the second frequency is higher than the first frequency used to illustrate Figures 1 and 2.

[0096] By comparing figures 2 and 3, we can note a significant change in the distribution of field lines within the timepiece 100 in figure 3. In particular, we can note in figure 3 field lines at a second depth P2 relative to the bottom of the case of the timepiece 100, the second depth P2 being less than the first depth P1.

[0097] In summary, and as shown in Figures 1 to 3, the field lines are modified by the mere presence of the timepiece 100. According to the present invention, the timepiece 100 can be equipped with a marker designed to provide the marked timepiece with a specific and predetermined magnetic response. In other words, and in particular, with reference to Figure 4, which forms a schematic diagram, the timepiece 100 includes a marker 110 which, by its presence, makes it possible to measure a specific, and at the very least measurable, magnetic response that differs from that of the same timepiece without the marker 110.

[0098] Marker 110 can be formed by: - all or part of the watch case (the case middle, the back, the lugs... ), - all or part of an internal component of the timepiece 100, such as for example a part of the movement, a rotor in the case of an automatic timepiece... According to one embodiment, the marker 110 may be the only electrically conductive component of the timepiece 100.

[0099] Marker 110 may typically include at least one metal part, and it may be foreseen that marker 110 may be formed at least in part from an alloy such as steel, stainless steel (for example, according to grade 1.4404 or AISI 316L, typically non-magnetic), or grade 1.4539 (or AISI 904L, typically non-magnetic), or brass, or an alloy of copper (typically non-magnetic), titanium (typically non-magnetic), gold (typically non-magnetic), platinum (typically non-magnetic)... [000100] The marker 110 can be formed by coating a material on a component of the timepiece 100. A local modification of the material of a component of the timepiece 100 can be envisaged, for example, localized laser treatment and / or localized ion implantation and / or localized deposition of a layer followed by heat treatment. diffusion and / or local carburizing / nitriding / oxidation treatment (or combinations thereof), with a view to modifying electrical and / or magnetic properties, for example by inducing a phase change, a modification of the crystalline structure, a modification of the chemical composition... [000101] The marker 110 can be formed by a component of the timepiece 100 that has undergone a specific heat treatment. For example, thermal annealing carried out between 500°C and 1200°C on a component comprising FeCo and / or FeNi, and / or FeSi, can make it possible to form a marker that will impose a specific magnetic response on the timepiece 100. [000102] Marker 110 can be formed in a material whose magnetic response varies with temperature. For example, marker 110 can be formed from a material with a Curie temperature between 250 K and 400 K. Below a temperature point defined by the material's physical properties (the Curie point), the material behaves like a ferromagnetic material, meaning it easily conducts and channels magnetic field lines. Above the Curie temperature, the material behaves paramagnetically, allowing magnetic field lines to pass through without influencing them, like air. Gadolinium could be used, for example. [000103] The marker 110 can be formed by an electrical coil or part of an electrical coil. [000104] The marker 110 can alternatively be a recess in material or a non-electrically conductive insert, formed or embedded in a component normally present in the timepiece and electrically conductive. The presence of the marker (typically occupying a volume normally occupied by an electrically conductive material) will then significantly modify the magnetic response of the timepiece 100 to exposure to the varying magnetic field. [000105] The marker 110 can just as easily be an electrically insulating component inserted within an electrically conductive component or between two electrically conductive components. It could be made of plastic, an insulating film, an insulating oxide layer, etc. The presence of the marker 110 will then significantly modify the paths of the induced electric currents and therefore the magnetic response of the timepiece 100 to exposure to the varying magnetic field. [000106] The marker 110 can finally be a magnetic part, that is to say a permanent magnet glued or arranged in the watch part 100 to modify its magnetic response. [000107] Figure 5 represents the timepiece 100 of Figure 4, including the marker 110, installed near a magnetic field source 21 and a measuring device 23 together forming a first variant of a control device 20 for measuring a magnetic response of the timepiece 100 including the marker 110 to exposure to a variable magnetic field. [000108] In detail, the control device 20 comprises: - the magnetic field source 21 formed by an electrical coil which can be described as a transmitting coil, - the measuring device 23 formed by an electrical coil which can be described as a receiving coil - a mounting 25 forming an imprint to receive the timepiece 100 including the marker 110 without play in order to guarantee a reliable and repeatable relative positioning between the timepiece 100 including the marker 110 and the magnetic field source 21 and / or the measuring device 23, - optional clamping means 26, here with an articulated arm which presses the timepiece 100 including the marker 110 against the magnetic field source 21, - a data acquisition and control system 24, including in particular: • at least one voltage measuring device V, connected to the magnetic field source 21 and / or the measuring device 23, • at least one current measuring device A, connected to the magnetic field source 21 and / or the measuring device 23, • at least one control unit UC (which may include an electronic control unit, a memory unit, a computing unit, a current generator, a voltage generator, internal means for measuring voltage or current, a communication unit ...) connected to the magnetic field source 21 and / or the measuring device 23, the voltage measuring device V, the current measuring device A, • a display device, which can also form a human-machine interface to receive control instructions from an operator. [000109] The control unit UC is intended to generate and impose an electric current in the magnetic field source 21 so as to expose the timepiece 100 including the marker 110 to a time-varying magnetic field whose predetermined magnetic field frequency is within a frequency range from 10 Hz to 10 7 Hz. [000110] If, for example, marker 110 is arranged on the surface (or near the surface) of the timepiece, it can be predicted that the frequency of the predetermined magnetic field is within a frequency range from 5.10 2 Hz to 10 7 Hz, preferably 10 4 Hz to 10 7 Hz, to get closer to the case illustrated in figure 3. [000111] If, for example, marker 110 is positioned far from the surface (or close to the center) of the timepiece, it can be predicted that the frequency of the predetermined magnetic field is within a frequency range from 10 Hz to 10 4 Hz and preferably within a range of frequencies ranging from 5.10 2 Hz at 5.10 3 Hz, to get closer to the case illustrated in figure 2. [000112] It is also possible to vary the frequency of the predetermined magnetic field, so as to cover a whole range of frequencies within a general frequency range from 10 Hz to 10 7 Hz. Thus, the entire timepiece 100, including marker 110, will be checked / measured / authenticated. Typically, a multi-frequency signal can be applied with a current whose time waveform is the sum of sinusoids of different frequencies fi, f2, fs, etc., judiciously chosen. Typically, the frequency of the predetermined magnetic field can be varied according to a pseudorandom binary sequence (PRBS). [000113] By way of example, Figure 10 shows an example of a signal that can be used to vary the frequency of the predetermined magnetic field. Figure 10 shows an example of an electric current that can be imposed in the magnetic field source 21. In Figure 10, the signal has an amplitude A varying, for example, from 0% to 100% of full scale, and a frequency that varies with time. The amplitude A of the signal in Figure 10 is generally square or pulsed. A multi-frequency signal can be used, which can be decomposed into a Fourier series, for example. [000114] Generally, the control unit UC is designed to generate and impose an electric current in the magnetic field source 21 so as to expose the timepiece 100, including the marker 110, to a time-varying magnetic field whose predetermined magnetic field amplitude is within a range of 0 T to 5.10 -1 T and preferably within a value range from 0 T to 6.10 -3 T, and preferably within a value range from 0 T to 10' 3 T. [000115] In the case of Figure 5, the magnetic field source 21 and the measuring device 23 are fixed to an electronic board substrate 22. The magnetic field source 21 and the measuring device 23 can be formed with printed circuits on the electronic board substrate 22. For example, loops can be formed or printed directly onto the electronic board substrate 22. Circular loops or loops of different shapes can be provided, depending on the geometry of the timepiece 100 and / or the marker 110. [000116] The control device 20 of Figure 5 therefore comprises a fixture 25 receiving and positioning: - on the one hand, the magnetic field source 21, the measuring device 23 and the electronic board substrate 22, On the other hand, the timepiece 100, including the marker 110, is held in place by an imprint or a counter-mold, such that the relative position between the timepiece 100, including the marker 110, the magnetic field source 21, and the measuring device 23 is reliable and repeatable. Clamping means 26 can be provided to press or hold the timepiece 100, including the marker 110, in contact with the magnetic field source 21, for example. Thus, there is no air gap between the timepiece 100, including the marker 110, and the magnetic field source 21, so that the timepiece 100, including the marker 110, is perfectly exposed to the varying magnetic field generated by the magnetic field source 21. [000117] The fixture 25, the clamping means 26, and the electronic board substrate 22 can be made of materials that are non-conductive and / or "transparent" to magnetic fields, i.e., with a relative magnetic permeability close to 1, and / or non-magnetic materials. The fixture 25 and clamping means 26 can be made of Teflon or plastic, for example. [000118] In the case of Figure 5, the magnetic field source 21 and the measuring device 23 are formed by separate coils. The magnetic field generated at each point in the vicinity of the magnetic field source 21 is variable. According to Faraday's law of electromagnetic induction, if the magnetic flux coupled with a loop or coil (the measuring device 23) varies with time, a voltage is induced across the coil forming the measuring device 23. It follows that by placing the measuring device 23 in the vicinity of the magnetic field source 21 and the timepiece 100 containing the marker 110 (the timepiece to be checked / measured / authenticated), an induced voltage is generated by the varying field across the coil of the measuring device 23. This induced voltage can serve as a basis for deducing the magnetic response of the timepiece 100 containing the marker 110. [000119] To perform a check of a watch part 100 (including a marker 110) in particular, it is possible to generate with the magnetic field source 21 the same magnetic field varying over time, and it is possible to measure iteratively the induced voltage: - without any 100 watch parts, - with a reference 100 watch part (including a reference 110 marker); - with a 100 watch part to be checked / measured / authenticated and including marker 110. [000120] These different induced voltages can be recorded, and a comparison can then be planned: - directly the induced voltage with the reference timepiece 100 and the induced voltage with the timepiece 100 including the marker 110 to be checked, - on the one hand, the induced voltage without any clockwork parts 100 and the voltage induced with the reference timepiece 100 and on the other hand the voltage induced without any timepiece 100 and the voltage induced with the timepiece 100 including the marker 110 to be checked. [000121] We can also foresee defining a frequency response as being the ratio between the induced voltage measured across the terminals of the coil (which is a receiving coil) of the measuring device 23 and the voltage applied across the terminals of the coil (which is a transmitting coil) of the magnetic field source 21, without current in the measuring coil. [000122] The analysis of these transfer functions for the timepiece 100, including the marker 110 to be controlled, allows the use of mathematical tools. Representations can be made in a Bode or Nyquist plot, which also allows for the comparison of measured timepieces. The analysis of non-sinusoidal periodic signals can be performed using a Fourier series decomposition. [000123] Thus, by comparing the induced voltages according to the different options, it is possible to quantify a difference between a magnetic response of the timepiece 100 including the marker 110 to be tested and a magnetic response of the reference timepiece 100. It is then possible to check / measure / authenticate the timepiece 100 including the marker 110 to be tested based on the identified difference (it is possible to verify that the difference is less than a threshold, it is possible to verify the absence or presence of a particular parameter or shape on the response curve...). [000124] It can be noted that in the example of Figure 5 the receiving coil of the measuring device 23 is arranged under the transmitting coil of the magnetic field source 21. However, other arrangements or locations can be chosen, both for the coil of the measuring device 23 and for the coil of the magnetic field source 21. [000125] Several coils can also be provided for the measuring device 23 and / or several coils for the magnetic field source 21. It is possible to provide simultaneous or sequential power to one or more coils of the magnetic field source 21, and it is possible to provide simultaneous or sequential measurement of an induced voltage across one or more coils of the measuring device 23. [000126] Figure 6 shows the timepiece 100 of Figure 4, including the marker 110, installed near a second variant of a control device 20 for measuring the magnetic response of the timepiece 100, including the marker 110, to exposure to a varying magnetic field. In particular, the timepiece 100, including the marker 110, is housed within the second variant of a control device 20, and the remainder of the control device 20 (similar to that shown in Figure 5) is not shown. In the example of the second embodiment shown in Figure 6, the timepiece 100, including the marker 110, will essentially be exposed to field lines passing through it and normal to its case back or crystal. [000127] In the example of the second embodiment shown in Figure 6, it can be noted that the control device 20 comprises only one electrical coil, which can be described as a transmitting-receiving coil. Indeed, it is possible to use a single coil, and the measurement of the current and / or voltage can provide the information necessary for control / measurement / authentication. [000128] In the case of a current measurement, one can quantify the amplitudes and / or phase shifts of the current (more precisely the current intensity) during tests: - without any 100 watch parts, - with a reference 100 watch part and including a reference 110 marker; - with a 100 watch part to be checked and including a 110 marker. [000129] It is possible to do the same with the voltage across the coil of the control device 20. [000130] Alternatively or in addition, the impedance of the transmitting-receiving coil of the control device 20 can be measured. The impedance of a coil is defined in complex notation by: U = Z . I with U the voltage across the coil and ] the current flowing through it. We can also recall that any coil can be characterized electrically by a resistance R and by a reactance X (a function of the current frequency and the inductance L of the coil) forming the complex impedance Z. [000131] In the presence of electrically conductive material in a timepiece to be tested, the field variation and induced currents cause a change in impedance compared to the case without the timepiece. In particular, the resistance R takes into account the internal Joule losses of the coil and also the eddy current losses in the timepiece being tested. The inductance L is related to the distribution of the field lines, which are modified by the presence of eddy currents in the timepiece. The presence of a marker that specifically and / or locally modifies the resistance R of the timepiece or at least one of its components can provide the marked timepiece with a specific and predetermined magnetic response. [000132] The different quantities are then a function of the frequency f of the varying magnetic field: - resistance: R(f), - inductance: L(f), - reactance: X(f), - impedance magnitude: Z(f), - Impedance argument: cp(f). Depending on the material and dimensions of the components of the timepiece and the 110 marker, these functions differ. They can therefore be used as a "signature" or "magnetic response" to characterize a timepiece equipped with the marker. In some cases, it may be advantageous to define functions that include measurements with the timepiece without the marker, with the timepiece equipped with the 110 marker, and without the timepiece to facilitate mathematical processing and graphical representation. [000133] Figure 7 shows a variant of the timepiece 100 of Figure 4, installed in a third variant of a control device for measuring the magnetic response of the variant of the timepiece 100 of Figure 4 to exposure to a varying magnetic field. The remainder of the control device (similar to that in Figure 5) is not shown. [000134] In Figure 7, it can be seen that the timepiece 100 includes two markers 110, each housed in one of the upper lugs of the timepiece 100. It is possible to install or not install a marker 110 in each lug of the timepiece 100. If the marker 110 is present in a lug, the value 1 can be assigned, and if it is absent, the value 0 can be assigned. In the case of Figure 7, going from left to right and from top to bottom, we would have a code 1100. [000135] In the case of the third variant of the measuring device in Figure 7, the control device 20 comprises only a single electrical coil surrounding the timepiece 100. The latter will essentially be exposed to field lines passing through it and parallel to its case back or crystal. As shown in Figure 7, measurements can be taken by placing the coil of the measuring device 20 at the lugs, so as to properly expose the markers 110 to the time-varying magnetic field. It is even possible to use a coil surrounding a horn only, in cases where it is possible to easily remove the bracelet for example. [000136] Figure 8 generally represents variant embodiments of the magnetic field source 21, for exposing the timepiece to a variable magnetic field. [000137] Figure 8, on the left, shows a single-phase system with a single diametral coil 21 A and a ferromagnetic cylinder 29. It can be understood that with a single coil 21 A, a variable magnetic field can be generated, typically by supplying the coil 21 A with a variable current, for example, a sinusoidal current, a square wave current, or more generally, a variable alternating current. If the current is alternating and has a period during which the current reverses, the field lines will have an amplitude varying over each half-period, and their direction will reverse between the first and second half-periods. The field draws power and its direction reverses, but its orientation does not change. [000138] Figure 8, on the right, shows a three-phase system with three diametrical coils 21A, 21B, 21C. In this case, the three coils 21A, 21B, 21C can be supplied by a three-phase current system with period T. The magnetic field rotates relative to the coils 21A, 21B, 21C. The amplitude of the field is constant over time. The field rotates at a speed of f revolutions per second. At 1000 Hz, the field then rotates at 1000 rev / s. [000139] With reference to Figures 5, 6, 7 and 8, it can be understood that numerous constructions and arrangement possibilities are possible both for generating the variable magnetic field and for measuring it once the timepiece 100, including the marker 110, is placed near the magnetic field source. These include: - a transmitting coil, arranged at a certain relative position with respect to the timepiece 100 comprising the marker 110, - several transmitting coils, placed at various relative positions with the 100 watch parts including marker 110, - a receiving coil, arranged at a certain relative position with respect to the timepiece 100 comprising the marker 110, - several receiving coils, placed at various relative positions with the timepiece 100 comprising the marker 110, - a transmitting-receiving coil, arranged at a certain relative position with respect to the timepiece 100 comprising the marker 110, - several transmitting-receiving coils, placed at various relative positions with the timepiece 100, - but we can also provide for one or more magnetic field sensors, placed at various relative positions with the timepiece 100 including the marker 110. Regarding the aforementioned magnetic field sensor, one can foresee a Hall effect sensor, a magnetoresistive sensor, a giant magnetoresistance, a SQUID type magnetometer (“Superconducting Quantum Interference Device”). [000140] Alternatively, a relative displacement can also be imposed between the timepiece 100 containing the marker 110 and the magnetic field source 21. In this case, two superimposed transmitting-receiving coils can be used to perform a differential measurement. The two transmitting-receiving coils are powered identically at a given frequency to generate the varying magnetic field and produce induced currents in the timepiece. If the timepiece 100 containing the marker 110 is moved along the axis of the transmitting-receiving coils, the resistance and reactance of the two transmitting-receiving coils change depending on the axial position of the timepiece containing the marker 110, taking into account the geometry and material of the timepiece.The measurement of resistances and / or inductances, reactances and / or impedances can then define the magnetic response which allows to control / measure / authenticate the watch part 100 including the marker 110. [000141] Figure 9 shows a graph representing the magnetic responses of several timepieces (watch parts), measured using the testing method according to the invention. Figure 9 shows normalized impedance curves, reconstructed after testing eleven timepieces. Each timepiece was exposed to the same magnetic field, which varied over time, with a frequency ranging from 10 Hz to 10 5 Hz, with a control device comprising a single transmitting-receiving coil, the impedance of which was measured simultaneously with exposure to the varying magnetic field of the timepiece. [000142] The timepieces tested were all of the same model, but ten timepieces from family A included a marker, and an eleventh timepiece from family B was a watch without a marker, despite an external visual appearance entirely similar to the timepieces equipped with a marker. Specifically, the case material of the ten timepieces from family A was a first grade of stainless steel (the marker), and the case material of the eleventh timepiece from family B was a second grade of stainless steel. [000143] It can be noted that Figure 9 shows all the curves of the timepieces in family A in a very close group, whereas the curve of the eleventh timepiece in family B is very different. It appears that the control method, consisting of exposing a timepiece to a varying magnetic field to measure a magnetic response, can be used to reliably control / measure / authenticate the timepiece containing a marker. [000144] Depending on the implementation of the marker and its location, it may be necessary or practical to disassemble part of the timepiece, such as removing the bracelet from the complete watch or removing the case back. [000145] Figure 11 shows, in its upper part, a graph representing the magnetic responses of two externally identical components or watch parts 100Ref and 100 shown in the lower part of Figure 11. The watch part 100Ref in the lower part of Figure 11 is a metallic part, for example, a bracelet link, made entirely of stainless steel, for example, non-magnetic. The watch part 100 in the lower part of Figure 11 is a metallic part having the same external appearance and shape as the watch part 100Ref (a bracelet link). However, the watch part 100 is made of stainless steel with an internal housing (or inset) containing a marker 110, for example, made of a ferromagnetic metal, which modifies the electrical conductivity and eddy current flow properties when exposed to a varying magnetic field. [000146] The timepiece 100Ref and the timepiece 100 have identical external dimensions, on the order of tens of millimeters, and a volume on the order of 50 mm 3 at 150 mm 3 The marker 110 of the timepiece 100 is an insert housed or embedded in the timepiece 100 and has external dimensions on the order of a millimeter, and a volume on the order of 1 mm 3 at 5 mm 3 Marker 110 may include iron, steel and may be ferromagnetic. [000147] It can be noted in the upper part of Figure 11 that the magnetic responses are notably different, with, for example, between 11000 Hz and 16000 Hz a clearly measurable difference which makes it possible to distinguish the two pieces from each other without any doubt, the two pieces having the same external appearance and predominantly the same material. [000148] Figure 12 shows in its upper part a graph of the magnetic responses of two watch parts comprising screws shown in the lower part of Figure 12. One of the watch parts comprises standard screws (Ref.), and the other of the watch parts comprises screws with a localized surface treatment forming A 110 marker. In the example in Figure 12, the screws (Ref) and the screws forming a 110 marker have the same appearance and external dimensions. These are screws used to attach components to a watch plate. The screws forming a 110 marker have undergone a localized surface treatment, in this case, case hardening or carburizing, enriching the external surface with carbon, thus forming a 110 marker. The case hardening or carburizing applied to the screws forming the 110 marker consists of enriching the steel of these screws with carbon to a depth of a few tenths of a millimeter. The hardness can range from 50 HRC to 63 HRC with such case hardening or carburizing. In this example, the screw heads have been treated, but it is possible to consider treating any other surface, or even the entire surface. [000149] It can be noted in the upper part of figure 12 that the magnetic responses of the watch parts including the screws Ref or the screws forming a marker 110 are markedly different, with for example at 15000 Hz a clearly measurable difference which makes it possible to distinguish one from the other without any doubt the two parts, which nevertheless have the same appearance and / or external dimensions. [000150] Figure 13 shows in its upper part a graph of the magnetic responses of three timepieces comprising an internal component of the same dimensions and material, shown in the lower part. The first timepiece comprises a first internal component with a first surface treatment forming a first marker 110-1, the second timepiece comprises a second internal component with a second surface treatment forming a second marker 110-2, the third timepiece comprises a third internal component with a third surface treatment forming a third marker 110-3. [000151] Watch parts can be, for example, watches with metal bridges or plates, and the components shown in the lower part of Figure 13 are typically metal plates supporting other organs. These components shown in the lower part of figure 13 can be made of brass, steel, gold, platinum or nickel phosphorus alloy, and have identical external dimensions, on the order of tens of millimeters. [000152] The first internal component received a first surface treatment forming a first marker 110-1, here an electrically conductive coating composed of rhodium (0.25 µm thick), nickel (0.25 µm thick), and gold (0.5 µm thick). The second internal component received a second surface treatment forming a second marker 110-2, here an electrically conductive nickel-phosphorus alloy (NiP12) coating 0.6 µm thick. The third internal component received a third surface treatment forming a third marker 110-3, here an electrically insulating alumina (Al2O3) coating 10 nm thick. [000153] It can be noted in the upper part of Figure 13 that the magnetic responses of the timepieces each comprising the first marker 110-1, or the second marker 110-2, or even the third marker 110-3 are markedly different, for example at approximately 3.10 4 Hz-4.10 4 Hz or even at 5.10 6 Hz, clearly measurable differences that allow us to distinguish without a doubt the three timepieces, which include an internal component that nevertheless has the same appearance and / or dimensions. Industrial application [000154] A control method according to the present invention, and its manufacture, are capable of industrial application. [000155] It will be understood that various modifications and / or improvements obvious to a person skilled in the art can be made to the different embodiments of the invention described in this description without departing from the scope of the invention. [000156] In particular, all the figures relate to a watch head, but the invention can be implemented for any type of watch part (a bracelet, a clasp...), accessories, watch parts forming jewelry, jewelry pieces.

Claims

DEMANDS [Claim 1] Timepiece (100), comprising at least one electrically conductive component providing the timepiece (100) with a given magnetic response to exposure to a predetermined and time-varying magnetic field, characterized in that the timepiece (100) comprises at least one marker (110) arranged to modify the given magnetic response of the timepiece (100), in order to provide the marked timepiece (100) with a specific and predetermined magnetic response. [Claim 2] Timepiece (100) according to claim 1, wherein the marker (110) is included in a functional component of the timepiece (100), such as a case, an automatic movement rotor, a case back, a bracelet of the timepiece (100). [Claim 3] A watch part (100) according to claim 2, wherein the marker (110) is a recess formed in the functional component. [Claim 4] A watch part (100) according to claim 2, wherein the marker (110) is an insert formed in the functional component. [Claim 5] Timepiece (100) according to claim 1, wherein the marker (110) forms a specific and / or non-functional component of the timepiece (100). [Claim 6] Timepiece (100) according to claim 5, wherein the marker (110) is a specific and / or non-functional component attached to a functional component of the timepiece (100), such as a case, an automatic movement rotor, a case back, a bracelet of the timepiece (100). [Claim 7] A timepiece (100) according to any one of claims 1 to 6, wherein the marker (110) is formed by a modification, for example local, of the material of a component of the timepiece (100), the modification, for example local, being formed for example by a localized laser treatment, and / or a localized ion implantation, and / or a localized deposition of a layer followed by a diffusion heat treatment, and / or a localized carburizing / nitriding / oxidizing treatment, and / or combinations thereof. [Claim 8] A timepiece (100) according to any one of claims 2 to 4 or according to claim 6 or 7, wherein: - the functional component is formed with a first material having at least one predetermined magnetic characteristic or one predetermined electrical characteristic, - the marker (110) is formed with a second material having at least one second predetermined magnetic characteristic or a second predetermined electrical characteristic, different respectively from the first predetermined magnetic characteristic or the first predetermined electrical characteristic. [Claim 9] A timepiece (100) according to any one of claims 2 to 4 or according to claims 6 to 8, wherein: - the functional component is formed with a first material having at least a first predetermined magnetic permeability or a first predetermined electrical conductivity, - the marker (110) is formed with a second material having at least a second predetermined magnetic permeability or a second predetermined electrical conductivity, different by at least 50% respectively from the first predetermined magnetic permeability or the first predetermined electrical conductivity. [Claim 10] Timepiece (100) according to any one of claims 1 to 9, wherein the marker (110): - is metallic, and / or - is a metallic portion of a component of the timepiece (100) that has undergone a predetermined surface treatment or heat treatment, or a local modification of the material, and / or - includes an electrical coil, and / or - exhibits a Curie temperature between 250 K and 400 K. [Claim 11] Timepiece (100) according to any one of claims 1 to 9, comprising a plurality of markers (110) each arranged to modify the given magnetic response of the timepiece (100), in order to provide the marked timepiece (100) with a specific and predetermined magnetic response. [Claim 12] Timepiece (100) according to claim 10, wherein at least two markers (110) are formed in different materials, so that each specifically modifies the given magnetic response of the timepiece (100), in order to provide the marked timepiece (100) with a specific and predetermined magnetic response. [Claim 13] Timepiece (100) according to claim 10 or 11, wherein at least two markers (110) are arranged at specific and different positions on the timepiece (100), so that each one specifically and locally modifies the given magnetic response of the timepiece (100), in order to provide the marked timepiece (100) with at least two specific, predetermined, and local magnetic responses. [Claim 14] Timepiece (100) according to any one of claims 10 to 12, wherein the plurality of markers (110) is arranged in the timepiece (100) so as to provide authentication coding with the specific and predetermined magnetic response. [Claim 15] A method for inspecting a timepiece, capable of comprising at least one marker arranged to modify the magnetic response given by the timepiece, the control method comprising the steps of: - to place the timepiece, or at least a part of the timepiece, in a predetermined relative position with respect to at least one source of magnetic field and / or with respect to at least one magnetic field measuring device, - exposing the timepiece, or at least a part of the timepiece, to at least one predetermined and time-varying magnetic field generated by the magnetic field source, - to measure, using at least one magnetic field measuring device, at least one characteristic of the magnetic field in the vicinity of the timepiece exposed to the predetermined magnetic field which varies over time, - to deduce a magnetic response of the timepiece from the measured characteristic of the magnetic field in the vicinity of the timepiece, - compare the magnetic response of the timepiece to a reference magnetic response to verify / check if the timepiece includes the marker.

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