Timepiece control device

Abstract

The invention relates to a control device for a timepiece comprising at least one electrically conductive component, the control device comprising at least: - a magnetic field source arranged so as to generate at least one predetermined, time-variable magnetic field, and / or a magnetic field measurement device; - a fitting arranged so as to accommodate a timepiece to be controlled, wherein the fitting is arranged so as to occupy at least one predetermined relative position with respect to the magnetic field source and / or with respect to the magnetic field measurement device so as: - to be able to expose the timepiece accommodated in the fitting to the predetermined, time-variable magnetic field generated by the magnetic field source; and / or - to allow the magnetic field measurement device to measure at least one characteristic of the magnetic field in the vicinity of the timepiece exposed to the predetermined, time-variable magnetic field.

Description

DESCRIPTION TITLE: Timepiece Control Device Technical field of the invention

[0001] The present invention relates generally to devices for controlling watch parts. In particular, the present invention relates to a control device, or a measuring device, or an authentication device designed to apply a magnetic field, such as a variable magnetic field, to or through at least one component of the watch part, in order to control, measure or authenticate said at least one component or the watch part itself. State of the art

[0002] It is known in the prior art of horology that magnetic fields can disrupt the operation of timepieces (especially the operation of watch movements). It is known to measure the resistance or robustness of timepieces to magnetic fields by applying magnetic fields to perform specific tests, called stop tests, as described, for example, in document CH 718 969 A2. However, watchmakers know that exposing timepieces to magnetic fields should be avoided.

[0003] It is known to perform control tests on components by applying a magnetic field. However, due to the interference caused by magnetic fields on the operation of watch parts, as mentioned above, this type of control based on exposure to magnetic fields is not used in the watchmaking industry. Description of the invention

[0004] One object of the present invention is to overcome the drawbacks of the prior art mentioned above and, in particular, first of all, to provide a control device, or a measuring device, or a device authentication, which can be used with a timepiece without disrupting its operation, in particular without disrupting its operation in a lasting or permanent way, and which allows for the rapid control, measurement or authentication of a component of the timepiece or the timepiece itself.

[0005] To this end, a first aspect of the invention relates to a control device for a timepiece comprising at least one electrically conductive component, the control device comprising at least: - a magnetic field source arranged to generate at least one predetermined magnetic field that varies over time, and / or a magnetic field measuring device, - a fixture arranged to receive a timepiece, or at least a part of the timepiece, to be inspected, in which the fixture is arranged to occupy at least one predetermined relative position with respect to the magnetic field source and / or with respect to the magnetic field measuring device such that: - to be able to expose the timepiece, or at least a part of the timepiece, received in the fixture to the predetermined and time-varying magnetic field generated by the magnetic field source, and / or - to allow the magnetic field measuring device to measure at least one characteristic of the magnetic field in the vicinity of the timepiece exposed to the predetermined magnetic field, which varies over time. According to the implementation described above, the control device is adapted, designed, and arranged to both expose a timepiece to a varying magnetic field and measure the magnetic field perturbed by the timepiece (the "perturbed" magnetic field is understood to be the magnetic field generated / measured in the presence of the timepiece and compared to the same field generated / measured in the absence of the timepiece). Thus, it is possible to determine the magnetic response of the timepiece to this field exposure. 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 stoppages or operational disruptions were observed).

[0006] According to a preferred embodiment, the invention relates to a control device for a timepiece comprising at least one electrically conductive component, the control device comprising at least: - a magnetic field source arranged to generate at least one predetermined magnetic field that varies over time, and a magnetic field measuring device, - a fixture arranged to receive a timepiece, or at least a part of the timepiece, to be inspected, wherein the fixture is arranged to occupy at least one predetermined relative position with respect to the magnetic field source and with respect to the magnetic field measuring device, and the inspection device is arranged to: - expose the timepiece, or at least a part of the timepiece, received in the fixture, to the predetermined and time-varying magnetic field generated by the magnetic field source, and - to simultaneously expose the timepiece to the predetermined and variable magnetic field, and to measure, using the magnetic field measuring device, at least one characteristic of the magnetic field in the vicinity of the timepiece exposed to the predetermined and variable magnetic field over time. Simultaneous measurement during exposure allows for the measurement of the resulting modified magnetic field. by the currents induced in the metallic or conductive components of the timepiece, in response to exposure.

[0007] The control device can be defined with the following characteristics, taken individually or in combination.

[0008] In one embodiment, the control device is designed to monitor a timepiece that is inactive or not in operation. In other words, the control device may be designed to perform a step that verifies that the timepiece is stopped, unpowered, or battery-free before exposing the timepiece to a magnetic field and / or measuring at least one characteristic of the magnetic field. In another embodiment, the control device is designed to monitor an assembly forming a timepiece or watch that can function even if it is stopped upon arrival in the fixture.

[0009] In one embodiment, the control device is free from a device for transmitting and / or receiving an identification signal. In another embodiment, the control device is free from a device for communicating with the timepiece.

[0010] According to one embodiment, the control device (comprising the magnetic field source and the measuring device) is separate from the timepiece.

[0011] In one embodiment, the control device is not designed or arranged to communicate with an identification transmitter / receiver (an electronic tag, RFID, NFC, etc.) located in the timepiece. In particular, the magnetic field source is not designed or arranged to generate an excitation or control signal for an identification or communication device located in the timepiece. In another embodiment, the control device is not designed or arranged to test the proper functioning of the timepiece (the watch) in a magnetic field; in particular, the control device This device is not designed or arranged to perform a stop test. It is not a chronometry test. In one embodiment, the control device is not designed or arranged to wind a timepiece (a watch). In another embodiment, the control device is not designed or arranged to start the movement of the timepiece or to move any component of the timepiece. In another embodiment, the control device is not designed or arranged to measure the movement of a rotor or a component of the timepiece (hands, for example).

[0012] In one embodiment, the fixture is integral with, or includes, at least part of the magnetic field source. Thus, the relative positioning between the fixture (and therefore the timepiece held in the fixture) and the magnetic field source is reliable, reproducible, and robust.

[0013] In one embodiment, the fixture is integral with, or includes, at least part of the magnetic field measuring device. Thus, the relative positioning between the fixture (and therefore the timepiece received in the fixture) and the magnetic field measuring device is reliable, reproducible, and robust.

[0014] According to one embodiment, the magnetic field source comprises at least: - a transmitting coil, - a current generator, connected to the transmitting coil. The current generator is typically a variable current generator (in voltage, current, frequency, signal shape).

[0015] In one embodiment, the fixture is integral with, or includes, the transmitting coil. Thus, the relative positioning between the fixture (and therefore the timepiece received in the fixture) and the transmitting coil is reliable, reproducible, and robust.

[0016] According to one embodiment, the current generator is arranged to circulate a time-varying electric current at through the transmitting coil. The current generator is typically a variable current generator (in voltage, intensity, frequency, signal shape).

[0017] In one embodiment, the magnetic field source comprises a plurality of transmitting coils, and the current generator is arranged to circulate a time-varying electric current through the plurality of transmitting coils, and preferably to circulate a time-varying electric current through the plurality of transmitting coils in a predefined sequence, to generate, for example, a rotating magnetic field with a rotational frequency of at least 50 revolutions per second, preferably at least 500 revolutions per second. In particular, the current generator can be arranged to circulate time-varying electric currents through the plurality of transmitting coils, such as the same electric current or different electric currents in the coils, typically out-of-phase electric currents.

[0018] According to one embodiment, the magnetic field source comprises at least two transmitting coils, and the current generator is connected to each of said at least two transmitting coils to circulate in each of said at least two transmitting coils an identical time-varying electric current.

[0019] According to one embodiment, the magnetic field measuring device comprises at least: - a receiving coil, - a voltage measuring device and / or a current measuring device, connected to the receiving coil.

[0020] According to one embodiment, said at least one receiving coil forms a transmitting coil of the magnetic field source. In other words, the control device may comprise a single coil which allows the emission of the predetermined variable magnetic field, and the measurement of the magnetic field in the vicinity of the timepiece.

[0021] In one embodiment, the fixture is integral with, or includes, the receiving coil. Thus, the relative positioning between the fixture (and therefore the timepiece received in the fixture) and the receiving coil is reliable, reproducible, and robust.

[0022] According to one embodiment, the magnetic field measurement device comprises at least one magnetic field sensor, such as a Hall effect sensor, a magnetoresistive sensor, a giant magnetoresistive magnetometer, or a SQUID (Superconducting Quantum Interference Device) type magnetometer. Such sensors may be provided instead of, or in addition to, a receiving coil or a transmitting-receiving coil.

[0023] According to one embodiment, the apparatus is arranged to be mobile relative to the magnetic field source and / or relative to the magnetic field measurement device at least between a first test position and a second test position.

[0024] According to one embodiment, the control device includes a clamping device, arranged to impose a reference position on the timepiece in the fixture.

[0025] According to one embodiment, the magnetic field source is arranged to vary over time the frequency of the predetermined magnetic field within a frequency range from 10 Hz to 10 7Hz. In a preferred embodiment, the magnetic field source is arranged to vary the frequency of the magnetic field over time (during exposure), and the measuring device is provided to measure at least one characteristic of the magnetic field in the vicinity of the exposed timepiece, simultaneously with the variation of the frequency over time, in particular to measure the magnetic field modified or altered by the currents induced in the metallic or conductive components of the timepiece as a function of the field frequency emitted magnetic field. In a preferred embodiment, the predetermined, time-varying magnetic field has a frequency and a period, and the frequency and period may vary over time during the stage of exposing the timepiece to the magnetic field. In a preferred embodiment, the frequency of the predetermined magnetic field may vary within one or more ranges of values ​​between 10 Hz and 10 7 Hz over time during the exposure of the timepiece to the magnetic field.

[0026] According to one embodiment, during the step of exposing the timepiece to the predetermined and time-varying magnetic field, the magnetic field source is arranged to vary the frequency of the predetermined magnetic field and, in particular, to vary a fundamental frequency of the predetermined magnetic field within a frequency range from 10 Hz to 10 7 Hz, preferably in a frequency range from 10 2 Hz to 10 7 Hz, preferably in a frequency range from 5.10 2 Hz to 10 7 Hz, preferably in a frequency range from 10 3 Hz to 10 7 Hz. In one embodiment, the magnetic field source is arranged to generate a fundamental frequency of the magnetic field at least greater than 10 Hz, at 10 2 Hz, at 5.10 2 Hz, at 10 3Hz. In one embodiment, the magnetic field source is arranged to generate a magnetic field frequency spectrum free of any signal having a frequency below 10 Hz, at 10 2 Hz, at 5.10 2 Hz, at 10 3 Hz.

[0027] In one embodiment, the magnetic field source is arranged to vary the amplitude of the predetermined magnetic field over time within a range of values ​​from 0 T to 5.10 1 T and preferably within a range of values ​​from 0 T to 6.10 3 T, and preferably within a range of values ​​from 0 T to 10 3 T or within a value range from 0 T to 5.10 4 T, or within a value range from 0 T to 3.10 -4 T, or within a value range from 0 T to 10 -4 T.

[0028] According to one embodiment, the magnetic field source is arranged to vary over time the orientation of the predetermined magnetic field by at least 10°, and preferably by at least 30°, relative to an initial orientation of the predetermined magnetic field.

[0029] According to one embodiment, the control device comprises a computing unit, arranged to: - to deduce a magnetic response of the timepiece from the measured characteristic of the magnetic field in the vicinity of the timepiece by the magnetic field measuring device, - compare the magnetic response of the timepiece to a reference magnetic response.

[0030] According to one embodiment, the magnetic field source is arranged to generate at least one predetermined magnetic field that varies over time, and 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.

[0031] According to one embodiment, the magnetic field source, and / or the magnetic field measuring device and / or the fixture is mobile relative to a frame of the test device, for example between a first position and at least a second position.

[0032] In one embodiment, the apparatus is free of any metallic parts. In particular, the apparatus is free of any metallic parts between the timepiece and the transmitting and / or receiving coil. Of course, this does not preclude the presence of an electrical coil (transmitting and / or receiving) comprising at least one electrically conductive turn to generate and / or measure the magnetic field, and the rest of the apparatus is free of any metal parts between the clockwork component and the transmitting coil and / or the receiving coil.

[0033] In one embodiment, the fixture includes or has at least one recess designed to receive the timepiece. In particular, the fixture includes or has at least one reference surface designed to come into contact with the timepiece, so as to place the timepiece in a reproducible and controlled orientation and position, both with respect to the Earth's gravitational field and with respect to the transmitting and / or receiving coils.

[0034] In one embodiment, the transmitting coil and / or the receiving coil and / or the magnetic field measuring sensor is arranged less than 10 mm, preferably less than 7 mm, preferably less than 5 mm, preferably less than 2 mm, preferably less than 1 mm from the timepiece received in the fixture. In another embodiment, the transmitting coil and / or the receiving coil and / or the magnetic field measuring sensor is arranged to make contact with the timepiece received in the fixture.

[0035] In one embodiment, the control device comprises at least one control unit for operating the magnetic field source and / or the magnetic field measuring device. In particular, the control unit is arranged to operate the magnetic field source and / or the magnetic field measuring device simultaneously or sequentially.

[0036] According to one embodiment, the control device includes at least one storage or memory unit for storing or memorizing setpoint values, control parameters, programs or parts of programs, measurements or measurement values.

[0037] According to one embodiment, at least part of the magnetic field source and / or at least part of the measuring device and / or the mounting is removable. In particular, the control device It may include a plurality of measurement kits, each comprising at least one part of the magnetic field source and / or at least one part of the measurement device and / or the fixture dedicated to a predetermined timepiece reference. Specifically, several fixtures may be provided, each comprising at least one coil (transmitting and / or receiving), each adapted to one or more specific timepiece references, said at least one coil being reversibly connected to the rest of the electrical / electronic part of the control device.

[0038] According to one embodiment, the control device includes at least one communication unit, arranged to communicate and / or exchange data with a remote server.

[0039] In one embodiment, the transmitting coil and / or the receiving coil has a dimension greater than or equal to 10 mm, preferably greater than or equal to 25 mm, preferably greater than or equal to 30 mm, preferably greater than or equal to 35 mm, preferably greater than or equal to 45 mm. In another embodiment, the timepiece has a characteristic dimension to be displayed, and the transmitting coil and / or the receiving coil has a measurement dimension between 0.1 and 0.5 times the characteristic dimension to be displayed.

[0040] According to one embodiment, the transmitting coil and / or the receiving coil has a dimension less than or equal to 20 mm, preferably less than or equal to 15 mm, preferably less than or equal to 10 mm, preferably less than or equal to 8 mm.

[0041] According to one embodiment, the transmitting coil and / or the receiving coil comprises at least one turn, preferably at least five turns, preferably at least thirty turns.

[0042] According to one embodiment, the transmitting coil and / or the receiving coil comprises at least one core, for example a ferromagnetic core, for example made of ferrite.

[0043] In one embodiment, the transmitting coil and / or the receiving coil is formed by an electrical conductor deposited on a substrate, such as a printed circuit board. In one embodiment, the transmitting coil and / or the receiving coil may include at least one turn that has a non-circular shape. In one embodiment, the printed circuit board may have a multi-layer structure and / or may include several transmitting coil(s) and / or receiving coil(s).

[0044] According to one embodiment, said at least one predetermined and time-varying magnetic field exhibits an amplitude with a sinusoidal, rectangular, triangular, jump, pseudorandom binary sequence (PRBS), and / or multifrequency signal (sum of several sinusoids of different chosen frequencies) waveform. It may be noted that the electric current generating the predetermined and time-varying magnetic field also exhibits this sinusoidal, rectangular, etc., waveform. 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 Ï2 for a certain time (a few periods), etc. According to one embodiment, the measurement can be carried out with a multi-frequency signal (which includes a sinusoid of first frequency fi and amplitude ai, a sinusoid of second frequency Ï2 and amplitude a2, a sinusoid of third frequency fa and amplitude as, etc.) which allows the test to be carried out quickly, with a single signal which includes the different desired frequencies.

[0045] According to one embodiment, the magnetic field source is arranged to expose the timepiece to a variable magnetic field, and during the timepiece exposure step 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.

[0046] According to one embodiment, the magnetic field source includes 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.

[0047] According to one embodiment, exposure to at least one predetermined and time-varying magnetic field is not intended to demagnetize a component or timepiece. In other words, exposure to at least one predetermined and time-varying magnetic field is neither suitable nor intended to demagnetize a component or timepiece. That is to say, the control device is not a demagnetizing instrument. To this end, the variable magnetic field has a frequency greater than 10 Hz, preferably greater than 50 Hz, preferably greater than 60 Hz, preferably greater than 80 Hz, preferably greater than 100 Hz, and so on. preferably above 1000 Hz. In particular, if the varying magnetic field sweeps or exhibits a range or spectrum of frequencies, then a substantial part of the range or spectrum of frequencies is above 50 Hz, preferably above 60 Hz, preferably above 80 Hz, preferably above 100 Hz, preferably above 1000 Hz.

[0048] According to one embodiment, exposure to at least one predetermined and time-varying magnetic field is not carried out to move or set in motion any component or mechanism of the timepiece. In other words, exposure to at least one predetermined and time-varying magnetic field is neither suitable nor intended to move or set in motion any component or mechanism of the timepiece. In other words, during the test method, and in particular during exposure to at least one predetermined and time-varying magnetic field: - if the components of the timepiece are stationary, then they remain stationary, - if components or mechanisms of the timepiece are mobile or in motion, then they remain mobile or in motion in the same way, without change.

[0049] In one embodiment, exposure to at least one predetermined and time-varying magnetic field is not performed for the purpose of exchanging data with the timepiece. In other words, exposure to at least one predetermined and time-varying magnetic field is neither suitable nor intended for establishing wireless communication with any communication components or units of the timepiece. That is to say, the control device is not a means of communication or data exchange with the timepiece.

[0050] According to one embodiment, exposure to at least one predetermined and time-varying magnetic field is not carried out to charge or transmit power to the timepiece. In other words, exposure to at least one predetermined and time-varying magnetic field is neither suitable nor intended for wirelessly charging the timepiece's components, organs, or batteries. That is to say, the control device is not a wireless charging or power supply. Description of the figures

[0051] 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:

[0052] [fig. 1] schematically represents at a given instant field lines of a variable magnetic field generated by a transmitting coil with a first frequency;

[0053] [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;

[0054] [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;

[0055] [fig. 4] schematically represents the timepiece in figures 2 and 3, including an electrically conductive component;

[0056] [fig. 5] represents the timepiece of figures 2 to 4, installed near a source of magnetic field and a measuring device together forming a first variant of a control device to measure a magnetic response of the timepiece to exposure to a variable magnetic field;

[0057] [fig. 6] represents the timepiece in figures 2 to 5, installed near a second variant of a control device to measure a magnetic response of the timepiece to exposure to a variable magnetic field;

[0058] [fig. 7] represents the timepiece from figures 2 to 6, installed near a third variant of a control device to measure a magnetic response of the timepiece to exposure to a varying magnetic field;

[0059] [fig. 8] generally represents concrete implementation variants of the magnetic field source, to expose the timepiece to a variable magnetic field;

[0060] [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;

[0061] [fig. 10] represents a graph showing an example of a variable signal that can be used when implementing this control method.

[0062] Detailed description of implementation method(s)

[0063] 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 symmetrical with respect to a plane parallel to the upper face or lower 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 (e.g., a ferromagnetic material) can be provided to direct or concentrate the magnetic field lines in a particular way.

[0064] 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 the field lines compared to the case in Figure 1.

[0065] In particular, and with reference to Figure 4, which forms a schematic diagram, the timepiece 100 includes an electrically conductive component 110. The electrically conductive component 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, such as a part of the movement, the coil of the motor...

[0066] The electrically conductive component 110 typically comprises at least one metallic part, and it is possible to form at least part of the electrically conductive component 110 with an alloy such as steel, stainless steel (for example, according to a grade 1.4404 (or AISI 316L), or a grade 1.4539 (or AISI 904L), or brass, or an alloy of copper, gold, titanium, platinum...

[0067] As is well known, a magnetic field, whose amplitude varies over time, induces electrical voltages in any conductive material placed within that field (the electrically conductive component 110 of the timepiece 100). These induced voltages cause 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 produced it. Eddy currents therefore flow in a direction that creates a field opposite to the field that gave rise to them, thus altering the distribution of the magnetic field.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] By comparing Figures 2 and 3, we can observe a significant change in the distribution of field lines within the timepiece 100 itself in Figure 3. In particular, we can note in Figure 3 the 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.

[0072] Figure 5 represents the timepiece 100 of Figures 2 to 4, 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 to exposure to a variable magnetic field.

[0073] Specifically, control device 20 includes: - 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 fixture 25 forming an imprint to receive the timepiece 100 without play in order to guarantee reliable and repeatable relative positioning between the timepiece 100 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 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 (CU) (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, etc.) connected to the magnetic field source 21 and / or to measuring device 23, to voltage measuring device V, to current measuring device A, • a display device, which can also form a human-machine interface to receive control instructions from an operator.

[0074] 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 with a time-varying magnetic field whose predetermined magnetic field frequency is within a frequency range from 10 Hz to 10 7 Hz.

[0075] If, for example, the electrically conductive component 110 is arranged on (or near) the surface of the timepiece, it can be predicted that the frequency of the predetermined magnetic field is within a frequency range of 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.

[0076] If, for example, the electrically conductive component 110 is positioned far from the surface (or close to the center) of the timepiece, we can predict that the frequency of the predetermined magnetic field will be within a frequency range from 10 Hz to 10 4 Hz and preferably in a frequency range from 5.10 2 Hz at 5.10 3 Hz, to get closer to the case illustrated in figure 2.

[0077] 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 7Hz. Thus, the entire 100-hour timepiece will be checked / measured / authenticated. Typically, a multi-frequency signal can be applied with a current whose time-domain waveform is the sum of sinusoids of different frequencies fi, f2, fa, etc., judiciously chosen. Typically, the frequency of the predetermined magnetic field can be varied according to a pseudorandom binary sequence (PRBS in English).

[0078] As an example, Figure 10 shows a signal that can be used to vary the frequency of a predetermined magnetic field. Figure 10 shows an example of an electric current that can be applied to 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 expected, which can be decomposed into a Fourier series, for example.

[0079] In general, 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 to a time-varying magnetic field whose predetermined magnetic field amplitude is within a range of 0 T to 5.10 1T 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.

[0080] In the case of Figure 5, the magnetic field source 21 and the measuring device 23 are fixed on 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, turns can be formed or printed directly on the electronic board substrate 22. Circular turns or turns of different shapes can be provided, depending on the geometry of the timepiece 100 and / or the electrically conductive component 110.

[0081] The control device 20 in 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 is held in place by an impression or a counter-mold, ensuring that the relative position between the timepiece 100, 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 in contact with the magnetic field source 21, for example. Thus, there is no air gap between the timepiece 100 and the magnetic field source 21, so that the timepiece 100 is perfectly exposed to the varying magnetic field generated by the magnetic field source 21.

[0082] The fixture 25, clamping means 26, and electronic board substrate 22 can be made from materials that are non-conductive and / or "transparent" to magnetic fields, i.e., with a magnetic permeability close to 1, and / or from non-magnetic materials. The fixture 25 and clamping means 26 could be made of Teflon or plastic, for example.

[0083] 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 turn or coil (the measuring device 23) varies with time, a voltage is induced across the coil forming the measuring device 23. Consequently, by placing the measuring device 23 in the vicinity of the magnetic field source 21 and the timepiece 100 (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.

[0084] To perform a check on a particular timepiece 100, it is possible to generate with the magnetic field source 21 the same magnetic field varying over time, and it is possible to iteratively measure the induced voltage: - without any 100 watch parts, - with a reference 100 timepiece; - with a 100 watch part to check / measure / authenticate.

[0085] These different induced voltages can be recorded, and we can then plan to compare them: - directly the induced voltage with the reference timepiece 100 and the induced voltage with the timepiece 100 to be tested, - on the one hand the induced voltage without any watch part 100 and the induced voltage with the reference watch part 100 and on the other hand the induced voltage without any watch part 100 and the induced voltage with the watch part 100 to be checked.

[0086] We can also plan to define a frequency response as the ratio between the induced voltage measured across the coil of the measuring device 23 and the voltage applied across the coil of the magnetic field source 21, with no current in the measuring coil.

[0087] Analyzing these transfer functions for the timepiece 100 under inspection allows the use of mathematical tools. Representations can be created on a Bode or Nyquist plot, which also allows for comparison between measured timepieces. The analysis of non-sinusoidal periodic signals can be performed using Fourier series decomposition.

[0088] Thus, by comparing the induced voltages according to the different options, we can quantify the difference between the magnetic response of the timepiece 100 being tested and the magnetic response of the reference timepiece 100. It is then possible to control / measure / authenticate the watch part 100 to be checked according to the identified deviation (we can check that the deviation is less than a threshold, we can check for the absence or presence of a particular parameter or shape on the response curve...).

[0089] It can be noted that in the example of figure 5 the coil of the measuring device 23 is arranged under the 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.

[0090] It is also possible to provide several coils for the measuring device 23 and / or several coils for the magnetic field source 21. It is possible to provide for the simultaneous or sequential supply of one or more coils of the magnetic field source 21, and it is possible to provide for the simultaneous or sequential measurement of an induced voltage across the terminals of one or more coils of the measuring device 23.

[0091] Figure 6 shows the timepiece 100 from Figures 2 to 5, installed near a second variant of a control device 20 for measuring the magnetic response of the timepiece 100 to exposure to a varying magnetic field. Specifically, the timepiece 100 is housed within the second variant of the control device 20, and the remainder of the control device 20 (similar to that in Figure 5) is not shown. In the example of the second embodiment shown in Figure 6, the timepiece 100 will essentially be exposed to field lines passing through it and normal to its case back or crystal.

[0092] In the example of the second embodiment shown in Figure 6, it can be noted that the control device 20 comprises only a single 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.

[0093] In the case of 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 timepiece; - with a 100 watch part to check.

[0094] It is possible to do the same with the voltage across the coil of the control device 20.

[0095] Alternatively or in addition, one can consider measuring the impedance of the transmitter-receiver coil of the control device 20. The impedance of a coil is known to be defined in complex notation by: U = Z . I with U the voltage across the coil and I 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.

[0096] In the presence of electrically conductive material in a timepiece being tested, the field variation and induced currents cause a change in impedance compared to the case without the timepiece. Specifically, the resistance R takes into account the internal Joule losses of the coil as well as 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.

[0097] 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), - magnitude of the impedance: Z(f), - argument of the impedance: cp(f). Depending on the material and dimensions of the timepiece's components, these functions vary. They can therefore be used as a "signature" or "magnetic response" to characterize a timepiece. In some cases, it is advantageous to define functions that include measurements both with and without the timepiece to facilitate mathematical processing and graphical representation.

[0098] Figure 7 shows the timepiece 100 from Figures 2 to 6, installed in a third variant of a control device for measuring the magnetic response of the timepiece 100 to exposure to a varying magnetic field. The rest of the control device (similar to that in Figure 5) is not shown. In the third variant, the timepiece 100 will essentially be exposed to field lines passing through it and parallel to its case back or crystal.

[0099] Figure 8 generally represents variants of the implementation of the magnetic field source 21, to expose the timepiece to a variable magnetic field. [000100] 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 half- period and the second half-period. The field draws and its direction reverses, but its orientation does not change. [000101] Figure 8, on the right, shows a three-phase system with three diametrical coils 21 A, 21 B, 21 C. In this case, it is possible to supply the three coils 21 A, 21 B, 21 C with a three-phase current system, of period T, the magnetic field rotates with respect to the coils 21 A, 21 B, 21 C. 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 therefore rotates at 1000 revolutions per second. [000102] With reference to Figures 5, 6, 7 and 8, it is understood that numerous constructions and arrangement possibilities are possible both for generating the variable magnetic field and for measuring it once the timepiece 100 is placed near the magnetic field source. These include: - a transmitting coil, arranged at a certain relative position with respect to the timepiece 100, - several transmitting coils, placed at various relative positions with the timepiece 100, - a receiving coil, arranged at a certain relative position with respect to the timepiece 100, - several receiving coils, placed at various relative positions with the timepiece 100, - a transmitting-receiving coil, arranged at a certain relative position with respect to the timepiece 100, - 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. Regarding the aforementioned magnetic field sensor, one can expect a Hall effect sensor, a magnetoresistive sensor, a magneto giant resistance, a SQUID type magnetometer (“Superconducting Quantum Interference Device >>”). [000103] Alternatively, a relative displacement can also be imposed between the timepiece 100 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 is moved along the axis of the transmitting-receiving coils, the resistance and reactance of the two transmitting-receiving coils change according to the axial position of the timepiece, taking into account the geometry and material of the timepiece. The measurement of the reactances and / or impedances can then define the magnetic response, which allows the timepiece 100 to be checked, measured, or authenticated. [000104] 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. [000105] The timepieces tested were all of the same model, but ten timepieces from family A were said to be compliant, and an eleventh timepiece from family B was a non-compliant watch, despite an external visual appearance entirely similar to the compliant timepieces. In detail, the material of the cases of the ten timepieces The case of the eleventh timepiece in Family A was made of a first grade of stainless steel, and the case material of the eleventh timepiece in Family B was made of a second grade of stainless steel. Also, the internal components present in the case of the ten timepieces in Family A during the test were compliant, while the internal components present in the case of the eleventh timepiece in Family B during the test were non-compliant, meaning they contained different materials and / or some geometric differences that could be identified between the timepieces. [000106] 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 testing method, consisting of exposing a timepiece to a varying magnetic field to measure a magnetic response, can be used to reliably test / measure / authenticate the timepiece. [000107] In this disclosure, the timepiece to be inspected may be a complete watch, a watch head (case and movement) as shown in Figure 5, but it may also include a watch subsystem such as a movement, a case without a cased movement, a strap, etc., or even a watch component such as a case back, a bezel, an oscillating weight, a balance spring, etc. Depending on the implementation, it may be necessary or practical to disassemble part of the timepiece, such as removing the strap from the complete watch or removing the case back. The timepiece may be a mechanical watch, an electromechanical watch, a quartz watch, or a component of a mechanical watch, an electromechanical watch, or a quartz watch. Industrial application [000108] A control method according to the present invention, and its manufacture, are capable of industrial application. [000109] 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.

Claims

DEMANDS

1. A control device for a timepiece comprising at least one electrically conductive component, the control device comprising at least: - a magnetic field source arranged to generate at least one predetermined magnetic field that varies over time, and / or a magnetic field measuring device, - a fixture arranged to receive a timepiece to be inspected, wherein the fixture is arranged to occupy at least one predetermined relative position with respect to the magnetic field source and / or with respect to the magnetic field measuring device such that: - to be able to expose the timepiece received in the fixture to the predetermined and time-varying magnetic field generated by the magnetic field source, and / or - to allow the measurement by the magnetic field measuring device of at least one characteristic of the magnetic field in the vicinity of the timepiece exposed to the predetermined magnetic field which varies over time.

2. Control device according to claim 1, wherein the apparatus is integral with, or comprises, at least a part of the magnetic field source.

3. Control device according to claim 1 or 2, wherein the fixture is integral with, or comprises, at least a part of the magnetic field measuring device.

4. A control device according to any one of claims 1 to 3, wherein the magnetic field source comprises at least: - a transmitting coil, - a current generator, connected to the transmitting coil.

5. Control device according to claim 4 in its dependence on claim 2, wherein the fixture is integral with, or comprises, the transmitting coil.

6. Control device according to claim 4 or 5, wherein the current generator is arranged to circulate a time-varying electric current through the transmitting coil.

7. Control device according to any one of claims 4 to 6, the magnetic field source comprising a plurality of transmitting coils, and wherein the current generator is arranged to circulate a time-varying electric current through the plurality of transmitting coils, and preferably to circulate a time-varying electric current through the plurality of transmitting coils in a predefined sequence, to generate, for example, a rotating magnetic field with, for example, a rotation frequency of at least 50 revolutions per second, preferably at least 500 revolutions per second.

8. Control device according to any one of claims 4 to 7, wherein the magnetic field source comprises at least two transmitting coils, and wherein the current generator is connected to each of said at least two transmitting coils to circulate in each of said at least two transmitting coils an identical time-varying electric current.

9. Control device according to any one of claims 1 to 8, in which the magnetic field measuring device comprises at least: - a receiving coil, - a voltage measuring device and / or a current measuring device, connected to the receiving coil.

10. Control device according to claim 9, wherein said at least one receiving coil forms a transmitting coil of the magnetic field source.

11. Control device according to claim 9 or 10 in their dependence on claim 3, wherein the fixture is integral with, or comprises, the receiving coil.

12. Control device according to any one of claims 1 to 11, wherein the magnetic field measuring device includes at least one magnetic field sensor, such as a Hall effect sensor, a magnetoresistive sensor, a giant magnetoresistance, a SQUID type magnetometer (“Superconducting Quantum Interference Device”).

13. Control device according to any one of claims 1 to 12, wherein the apparatus is arranged to be mobile relative to the magnetic field source and / or relative to the magnetic field measuring device at least between a first test position and a second test position.

14. Control device according to any one of claims 1 to 13, comprising a clamping device, arranged to impose a reference position on the timepiece in the setting.

15. Control device according to any one of claims 1 to 14, wherein the magnetic field source is arranged to vary over time the frequency of the predetermined magnetic field within a frequency range from 10 Hz to 10 7 Hz.

16. Control device according to any one of claims 1 to 15, wherein the magnetic field source is arranged to vary over time the amplitude of the predetermined magnetic field within a range of values ​​from 0 T to 5.10 1 T and preferably within a range of values ​​from 0 T to 6.10 3 T, and preferably within a range of values ​​from 0 to 10 3 T.

17. A control device according to any one of claims 1 to 16, wherein the magnetic field source is arranged to vary over time the orientation of the predetermined magnetic field of minus 10°, and preferably at least 30°, relative to an initial orientation of the predetermined magnetic field.

18. A control device according to any one of claims 1 to 17, comprising a calculation unit arranged to: - deduce a magnetic response of the timepiece from the measured characteristic of the magnetic field in the vicinity of the timepiece by the magnetic field measuring device, - compare the magnetic response of the timepiece to a reference magnetic response.

Images