Method for controlling a component of a quartz watch or a quartz watch

Abstract

The invention relates to a method for controlling a quartz watch, the method comprising the steps of: - placing the quartz watch in a predetermined relative position with respect to at least one magnetic field source and / or with respect to at least one magnetic field measurement device; - exposing the quartz watch to at least one predetermined time-variable magnetic field; - measuring at least one characteristic of the magnetic field in the vicinity of the quartz watch exposed to the predetermined time-variable magnetic field; - inferring a magnetic response of the quartz watch from the measured characteristic of the magnetic field; - comparing the magnetic response of the quartz watch with a reference magnetic response.

Description

DESCRIPTION TITLE: Method for testing a component of a quartz watch or quartz timepiece Technical field of the invention

[0001] The present invention relates generally to methods for testing quartz watches. In particular, the present invention relates to a testing method, a measurement method, or an authentication method involving the application of a magnetic field, such as a variable magnetic field, to or through at least one component of the quartz watch, to test, measure, or authenticate said component or the quartz watch itself. State of the art

[0002] It is known in the prior art of horology that magnetic fields can disrupt the operation of quartz watches. It is known to measure the resistance or robustness of watches 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 quartz watches should not be exposed to magnetic fields.

[0003] It is known to perform quality control tests on components by applying a magnetic field. However, due to the interference caused by magnetic fields on the operation of quartz watches, 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 propose a method of control, or a method of measurement, or a authentication method, which can be applied to a quartz watch 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 quartz watch or the quartz watch itself.

[0005] To this end, a first aspect of the invention relates to a method for testing a quartz watch comprising at least one electrically conductive component, or a component of the quartz watch, the testing method comprising a testing phase with the steps of: - to place the quartz watch, or at least a part of the quartz watch (i.e., a functional subset of the quartz watch, an assembly of parts of the quartz watch), 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, - exposing the quartz watch, or at least a part of the quartz watch, 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 quartz watch exposed to the predetermined magnetic field which varies over time, - deduce the magnetic response of the quartz watch from the measured characteristic of the magnetic field in the vicinity of the quartz watch, - compare the magnetic response of the quartz watch to a reference magnetic response.

[0006] According to the implementation above, the control method includes a step of exposing the quartz watch to at least one predetermined magnetic field that varies over time. The applicant It was observed with surprise that such exposure to varying magnetic fields, particularly low-amplitude varying magnetic fields, did not disrupt the operation of the quartz watch (no stops or malfunctions were observed). Furthermore, measuring at least one characteristic of the magnetic field in the vicinity of the quartz watch allows for the deduction of a response from the quartz watch that can be compared to a reference magnetic response. This allows for the control, measurement, or authentication of a component of the quartz watch or the quartz watch itself, particularly by: - verifying / checking the similarity of the quartz watch's response with a reference magnetic response, and / or - measuring the difference between the quartz watch's response and the reference magnetic response, - comparing the response of the quartz watch with templates built around the reference magnetic response... Thus, the quartz watch can be checked, measured or authenticated quickly, without affecting its operation, and without necessarily having to disassemble it.

[0007] More generally, the invention may relate to a method for testing a quartz watch comprising at least one electrically conductive component, or a component of the quartz watch, the testing method comprising a testing phase with the steps of: - place the quartz watch, or the quartz watch component, 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, - exposing the quartz watch, or the quartz watch component, to at least one predetermined and time-varying magnetic field generated by the magnetic field source, - measure, using at least one field measuring device magnetic, at least one characteristic of the magnetic field in the vicinity of the quartz watch, or of the quartz watch component, exposed to the predetermined magnetic field which varies over time, - to deduce a magnetic response of the quartz watch, or of the quartz watch component, from the measured characteristic of the magnetic field in the vicinity of the quartz watch, - compare the magnetic response of the quartz watch, or of the quartz watch component, to a reference magnetic response.

[0008] In particular, the invention may relate to a method for testing a component of a quartz watch comprising at least one electrically conductive component, the testing method comprising a testing phase with the steps of: - place the quartz watch, or at least a part of the quartz watch, in 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 quartz watch 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 quartz watch exposed to the predetermined magnetic field which varies over time, - deduce the magnetic response of the quartz watch from the measured characteristic of the magnetic field in the vicinity of the quartz watch, - compare the magnetic response of the quartz watch to a reference magnetic response. In other words, the method involves checking, measuring, and verifying at least one electrically conductive component, and therefore, consequently, the quartz watch that contains it.

[0009] The control method can be defined by the following characteristics, taken individually or in combination.

[0010] In one embodiment, the step of exposing the quartz watch to a predetermined, time-varying magnetic field (and / or the step of measuring at least one characteristic of the magnetic field in the vicinity of the quartz watch exposed to the predetermined, time-varying magnetic field) is performed on the quartz watch while it is inactive or not operating. In other words, the method may include a step of stopping or allowing the quartz watch to stop before performing the step of exposing the quartz watch to the magnetic field, and / or the step of measuring at least one characteristic of the magnetic field in the vicinity of the quartz watch exposed to the predetermined, time-varying magnetic field.In other words, the invention may relate to a method for testing a component of a quartz watch or a non-functional, unpowered, or stopped quartz watch (the quartz watch movement is stopped). In one embodiment, the quartz watch being tested is "inactive" at the time of the test: there is no battery in the quartz watch, no current flowing through any electrical or electronic circuit of the quartz watch... In any case, and in a preferred embodiment, the quartz watch is an assembly of several components, such as a complete watch in working order (but which may nevertheless be stopped or from which the battery has been removed).

[0011] In one embodiment, the quartz watch is free of an electronic identification device. In another embodiment, the quartz watch is free of a device for emitting and / or receiving magnetic fields or radio waves to communicate with a control device. In another embodiment, the quartz watch is free of a device for communicating with a device external to the quartz watch.

[0012] In one embodiment, the control method includes an initial step of acquiring a control device and the quartz watch. In one embodiment, the control device comprises the magnetic field source and the magnetic field measuring device (it being understood that the magnetic field source and the magnetic field measuring device may be separate and form distinct devices, or may be combined in a single device). In other words, the magnetic field source and the measuring device are separate from the quartz watch and are not part of it.

[0013] In one embodiment, the control method is free from any communication step with the quartz watch and / or with a component of the quartz watch. In other words, the quartz watch is passive during the execution of the control method.

[0014] In one embodiment, the step of measuring at least one characteristic of the magnetic field in the vicinity of the quartz watch exposed to the predetermined and time-varying magnetic field is simultaneous with the step of exposing the quartz watch to the predetermined and time-varying magnetic field. In particular, the step of measuring at least one characteristic of the magnetic field in the vicinity of the quartz watch exposed to the predetermined and time-varying magnetic field is not the measurement of a signal emitted by a device of the quartz watch in response to the step of exposing the quartz watch to the predetermined and time-varying magnetic field.According to a preferred embodiment, the quartz watch is exposed to a predetermined magnetic field whose frequency varies over time, and the measurement of at least one characteristic of the magnetic field in the vicinity of the quartz watch exposed to the predetermined magnetic field and varying over time is carried out simultaneously with the variation of the frequency over time, in particular to measure the magnetic field modified by the currents induced in the metallic components or. quartz watch conductors depending on the frequency of the emitted magnetic field.

[0015] According to one embodiment, the step of measuring at least one characteristic of the magnetic field in the vicinity of the quartz watch exposed to the predetermined magnetic field is a step of measuring the field generated by the magnetic field source, modified or altered by the magnetic field generated by the currents induced in the metallic component(s) of the timepiece in response to the exposure. The effect of the induced currents is directly dependent on the exposure and the metallic components of the quartz watch, thus providing a signature. This contrasts with an identification method based on communication with a transmitter / receiver (an electronic tag, RFID, NFC, etc.).Placed in a quartz watch, the measurement step of this control method is not a measurement step of a particular signal emitted by a passive or active electronic component of the quartz watch; it is a measurement of the magnetic field resulting from or modified by the currents induced in the metallic components by exposure to the predetermined magnetic field. The step of exposing the quartz watch to the predetermined and time-varying magnetic field in this control method is not a step of emitting an excitation or control signal to an identification component or device of the quartz watch.

[0016] In the case of a complete quartz watch, the control method can be applied without current or battery, thus without using the coil(s) of the electric motor. This is because the method utilizes the currents induced by the varying magnetic field in the conductive components, which alter the magnetic field and thus constitute the signature.

[0017] The control method can also be applied when the complete quartz watch is running, and therefore powered. In this In this case, the overall resulting external field is generated by the external transmitting coil, the motor coil and its magnet(s), and also by the currents induced by the varying external field, which modify the resulting external field. It is these induced currents that are used to distinguish the effect of the change in the external field and thus create the signature. The applied external magnetic field is of such low amplitude that it does not interfere with the operation of the quartz watch. Furthermore, the frequencies imposed by the transmitting coil, and therefore those of the induced currents, can be very different from the frequencies associated with the field of the motor coil and the magnet, which allows the effect of the induced currents to be clearly distinguished.

[0018] According to one embodiment, during the step of exposing the quartz watch to the 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 varies over time. As seen above, exposing the quartz watch to such a time-varying magnetic field does not impair its operation. In a preferred embodiment, the predetermined, time-varying magnetic field has a frequency and a period, and the frequency and period can vary over time during the step of exposing the quartz watch to the magnetic field.

[0019] According to one embodiment, during the step of exposing the quartz watch to the predetermined and time-varying magnetic field, the frequency of the predetermined magnetic field is within a frequency range from 10 Hz to 10 7Hz. According to a preferred embodiment, the frequency of the magnetic field predetermined can vary within one or more range(s) of values ​​whose limits are between 10 Hz and 10 7 Hz over time during the quartz watch's exposure to the magnetic field.

[0020] According to one embodiment, during the step of exposing the quartz watch to the predetermined and time-varying magnetic field, the frequency of the predetermined magnetic field varies, and in particular a fundamental frequency of the predetermined magnetic field varies 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 7Hz. According to one embodiment, the fundamental frequency of the magnetic field is at least greater than 10 Hz, at 10 2 Hz, at 5.10 2 Hz, at 10 3 Hz. According to one embodiment, the frequency spectrum of the magnetic field is free of any signal having a frequency below 10 Hz, at 10 2 Hz, at 5.10 2 Hz, at 10 3 Hz.

[0021] According to one embodiment, said quartz watch includes an intercalating component: - arranged between said at least one electrically conductive component and said at least one magnetic field source and / or said at least one magnetic field measuring device, and - having a thickness of at least 1 mm and / or an electrical conductivity of at least 1.10 7S / m (for siemens per meter) and / or a relative magnetic permeability greater than 50 and preferably a thickness of at least 2 mm and / or an electrical conductivity of at least 1.5 x 10 7 S / m and / or a relative magnetic permeability greater than 80, and during the step of exposing the quartz watch to the predetermined and time-varying magnetic field, the frequency of the predetermined magnetic field is 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. The intermediate component (of the watch to quartz) forms a screen or a screen component arranged between said at least one electrically conductive component and said at least one magnetic field source (or the measuring device). According to this embodiment, if the intervening component is "solid" with a significant thickness, greater than 1 mm or with an electrical conductivity of at least 1.10 7 S / m or with a significant magnetic permeability, greater than 50 (i.e., the electrically conductive component targeted by the method is arranged within the quartz watch itself, behind the intercalated component), then it is possible to use a magnetic field with a low frequency to ensure that it "passes through" the intercalated component and thus performs a robust and reliable control.

[0022] According to one embodiment, said quartz watch includes an intercalating component: - arranged between said at least one electrically conductive component and said at least one magnetic field source and / or said at least one magnetic field measuring device, and - having a thickness of no more than 2 mm and / or an electrical conductivity of no more than 1.10 7 S / m (for siemens per meter) and / or a relative magnetic permeability of less than 50, and preferably a thickness of at most 1 mm or at most 0.5 mm and / or an electrical conductivity of at most 5.10 6 S / m and / or a relative magnetic permeability less than 5, and during the step of exposing the quartz watch to the predetermined and time-varying magnetic field, 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 7Hz. According to this embodiment, if the intercalated component is "thin" (with a small thickness, less than 1 mm, or with low magnetic permeability, less than 50) or even absent (i.e., the electrically conductive component targeted by the method is arranged on the surface of the quartz watch), then a magnetic field with a high frequency can be used to accurately control, measure, or authenticate the electrically conductive component. Thus, the rest of the components (in particular the components arranged further inside the quartz watch than the electrically conductive component) will have less interaction with the varying magnetic field, so that the control will be "focused" or "carried out mainly" on said electrically conductive component of the quartz watch targeted by the control method.

[0023] According to one embodiment, during the step of exposing the quartz watch to the predetermined and time-varying magnetic field, the amplitude of the predetermined magnetic field is modified over time to obtain a powerful magnetic field, preferably according to a sinusoidal function.

[0024] According to one embodiment, during the step of exposing the quartz watch to the predetermined and time-varying magnetic field, 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 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.

[0025] In one embodiment, during the step of exposing the quartz watch to a predetermined and time-varying magnetic field, a relative motion is imposed between the quartz watch and the magnetic field source. This relative motion allows the quartz watch to be exposed to a varying magnetic field, even if the magnetic field source generates a constant or fixed magnetic field.

[0026] According to one embodiment, during the step of exposing the quartz watch to the 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°.

[0027] According to one embodiment, during the step of exposing the quartz watch to the 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.

[0028] According to one embodiment, the step of exposing the quartz watch to the predetermined and time-varying magnetic field includes a step of electrically supplying at least one electrical coil, or even at least two electrical coils, simultaneously or with a time offset.

[0029] According to one embodiment, the step of measuring at least one characteristic of the magnetic field in the vicinity of the quartz watch 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.

[0030] According to one embodiment, the step of measuring at least one characteristic of the magnetic field in the vicinity of the quartz watch 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.

[0031] According to one embodiment, the step of deducing the magnetic response of the quartz watch 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 quartz watch, 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 quartz watch, - an analysis phase involving the construction of a Bode plot, and / or a Nyquist plot, and / or a Fourier series decomposition. Placing the quartz watch in a changing magnetic field alters the distribution and amplitude of the magnetic field within and around the watch. This resulting modified magnetic field is measured and analyzed to deduce the magnetic response of the quartz watch.

[0032] According to one embodiment, the control method includes an initial baseline phase with the steps of: - place a reference quartz watch 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 quartz watch 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 quartz watch exposed to the predetermined magnetic field, which varies over time. - deduce a magnetic response of the reference quartz watch from the measured characteristic of the magnetic field in the vicinity of the quartz watch, - record the magnetic response of the reference quartz watch.

[0033] In one embodiment, the step of positioning the quartz watch 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 quartz watch in a fixture and / or clamping the quartz watch in a fixture, and / or mechanically stopping the quartz watch against or within a fixture. In another embodiment, the steps of placing the quartz watch in a fixture and / or clamping the quartz watch in a fixture, and / or mechanically stopping the quartz watch against or within a fixture, are performed with the quartz watch in contact or against a positioning portion of said at least one magnetic field source. Thus, the relative position between the quartz watch and the magnetic field source and / or the measuring device is reproducible, reliable, and robust.

[0034] In one embodiment, the step of placing the quartz watch 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 quartz watch within 10 mm, preferably within 7 mm, preferably within 5 mm, preferably within 2 mm, preferably within 1 mm, of at least one magnetic field source and / or with respect to at least one magnetic field measuring device, and most preferably, the quartz watch 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 quartz watch is well exposed to the magnetic field, and / or is located near the measuring device, which ensures reliable measurements with a good signal-to-noise ratio.

[0035] According to one embodiment, the step of exposing the quartz watch to a predetermined and variable magnetic field during the time 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 quartz watch exposed to the predetermined and time-varying magnetic field are carried out at least partially simultaneously.

[0036] According to one embodiment, the step of exposing the quartz watch to a predetermined and time-varying magnetic field generated by the magnetic field source, and the step of measuring at least one characteristic of the magnetic field in the vicinity of the quartz watch exposed to the predetermined and time-varying 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.

[0037] According to one embodiment, the step of exposing the quartz watch to a predetermined and time-varying magnetic field generated by the magnetic field source includes: - a first control phase consisting of exposing a first portion of the quartz watch to a first predetermined magnetic field that varies over time, generated by the magnetic field source, - a second control step consisting of exposing a second portion of the quartz watch to a second predetermined magnetic field, which varies over time, generated by the magnetic field source. This allows for the control, measurement, and authentication of distinct parts of the same quartz watch.

[0038] In one embodiment, the inspection method is a control method implemented after a specific manufacturing operation of the quartz watch. It may be necessary to inspect an assembly operation to verify that all components are present and / or arranged in the correct position. It may also be necessary to perform a "new" inspection. right after manufacturing to record the response so that it can be compared when returning to the maintenance workshop, up to several years later.

[0039] In one embodiment, the control method constitutes a method for authenticating the quartz watch, 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: - place the new quartz watch in 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 new quartz watch 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 quartz watch exposed to the predetermined magnetic field, which varies over time, - deduce the magnetic response of the new quartz watch from the measured characteristic of the magnetic field in the vicinity of the new quartz watch, - record the magnetic response of the new quartz watch as a reference magnetic response.

[0040] According to one embodiment, the magnetic response of the new quartz watch forms a reference signature, and / or the magnetic response of the quartz watch to be checked forms a quartz watch signature.

[0041] According to one embodiment, the control method includes a final phase comprising the steps of: - quantify the difference between the magnetic response of the quartz watch and the reference magnetic response, and / or - compare, with a predetermined threshold, the difference between the magnetic response of the quartz watch and the reference magnetic response, and / or - qualify the checked quartz watch as a compliant quartz watch or an authentic quartz watch, in particular if a difference between the magnetic response of the quartz watch and the reference magnetic response is less than a predetermined threshold and / or is acceptable.

[0042] According to one embodiment, during the step of exposing the quartz watch to the 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 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.

[0043] In one embodiment, the magnetic field source comprises at least one magnet, such as a permanent magnet, and the step of exposing the quartz watch to at least one predetermined and time-varying magnetic field generated by the magnetic field source includes a step of imposing at least a relative movement between the magnetic field source and the quartz watch.

[0044] 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. 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, 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 Ï2 and amplitude a2, a sinusoid of third frequency fa and amplitude as, etc.) which allows the test to be done quickly, with a single signal which includes the different desired frequencies.

[0045] In one embodiment, the quartz watch includes a quartz movement. In another embodiment, the quartz watch may include an integrated circuit. In another embodiment, the quartz watch may include a Lavet motor. In another embodiment, the quartz watch may include an electronic oscillator controlled by a quartz crystal resonator. In another embodiment, the quartz watch may include a display with hands driven by the quartz movement. In another embodiment, the quartz watch may A quartz watch can be a digital or electronic watch, or even a connected watch or "smartwatch." In one embodiment, a quartz watch can also be an automatic quartz watch, meaning a watch with a quartz movement powered by a small energy recovery system similar to that of a self-winding mechanical watch.

[0046] According to one embodiment, the method of controlling the quartz watch is not equivalent to a method of controlling a mechanical or automatic watch or timepiece (without a quartz movement or electronic time base).

[0047] In one embodiment, exposure to at least one predetermined, time-varying magnetic field is not intended to demagnetize a component or the quartz watch. In other words, exposure to at least one predetermined, time-varying magnetic field is neither suitable nor intended to demagnetize a component or the quartz watch. For this purpose, 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 preferably greater than 1000 Hz. In particular, if the variable magnetic field sweeps or exhibits a range or spectrum of frequencies, then a substantial portion of the range or spectrum of frequencies is greater than 50 Hz, preferably greater than 60 Hz, preferably greater than 80 Hz, preferably greater than 100 Hz, and preferably greater than 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 a component or mechanism of the quartz watch. In other words, exposure to at least one predetermined and time-varying magnetic field is not appropriate or intended to move or set in motion a component or mechanism of the quartz watch. In other words, during the test method, and in particular during exposure to at least one predetermined magnetic field that varies over time: - if the components of the quartz watch are stationary, then they remain stationary, - if components or mechanisms of the quartz watch 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 used to exchange data with the quartz watch. In other words, exposure to at least one predetermined and time-varying magnetic field is neither suitable nor intended for establishing wireless communication with the quartz watch's communication components or units.

[0050] In one embodiment, exposure to at least one predetermined and time-varying magnetic field is not performed to charge or transmit energy to the quartz watch. In other words, exposure to at least one predetermined and time-varying magnetic field is neither suitable nor intended for wirelessly charging components, organs, or batteries of the quartz watch. 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 transmitting coil, when a quartz watch is placed near the transmitting coil;

[0054] [fig. 3] schematically represents the field lines of the variable magnetic field generated by the transmitting coil with a second frequency, when the quartz watch is always placed near the transmitting coil;

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

[0056] [fig. 5] represents the quartz watch 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 quartz watch to exposure to a variable magnetic field;

[0057] [fig. 6] represents the quartz watch from figures 2 to 5, installed near a second variant of a control device to measure a magnetic response of the quartz watch to exposure to a varying magnetic field;

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

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

[0060] [fig. 9] represents a graph showing magnetic responses of several quartz watches, 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 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.

[0064] Figure 2 schematically represents the field lines of the varying magnetic field generated by the transmitting coil 10 when a quartz watch 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 the transmitting coil 10 is supplied with an electric current. Variable (typically an alternating current, for example a sinusoidal or square wave current), Figure 2 represents the distribution of field lines at a given instant. It can be noted that the quartz watch 100 significantly alters the distribution of field lines compared to the case in Figure 1.

[0065] In particular, and with reference to Figure 4, which forms a schematic diagram, the quartz watch 100 includes an electrically conductive component 110. This electrically conductive component 110 can be formed by: - all or part of the quartz watch case (the case middle, the back, the lugs... ), - all or part of an internal component of the quartz watch, such as a part of the movement, a part of the Lavet motor, such as the Lavet motor coil...

[0066] The electrically conductive component 110 typically comprises at least one metal part, and it may be foreseen that the electrically conductive component 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), or grade 1.4539 (or AISI 904L)), or brass, or an alloy of copper, titanium, gold, 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 electrical component 110 of the quartz watch 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, exhibits 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 quartz watch 100 itself, at a first depth P1 relative to the bottom of the case of the quartz watch 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 quartz watch 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 note a significant change in the distribution of field lines within the quartz watch 100 itself 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 quartz watch 100, the second depth P2 being less than the first depth P1.

[0072] Figure 5 represents the quartz watch 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 quartz watch 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 that can to be called a receiving coil - a mounting 25 forming an imprint to receive the quartz watch 100 without play in order to guarantee a reliable and repeatable relative positioning between the quartz watch 100 and the magnetic field source 21 and / or the measuring device 23, - optional clamping means 26, including here an articulated arm which presses the quartz watch 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 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.

[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 quartz watch 100 with a magnetic field that varies over time, the frequency of which is predetermined and falls 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 quartz watch, it can be predicted that the frequency of the predetermined magnetic field is between in 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.

[0076] If, for example, the electrically conductive component 110 is arranged far from the surface (or close to the center) of the quartz watch, 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 quartz watch 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 h, f2, fa, etc., judiciously chosen. Typically, the frequency of the predetermined magnetic field can be varied according to a pseudorandom binary sequence (PRBS).

[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 quartz watch 100 with a field a time-varying magnetic field whose predetermined magnetic field amplitude is within a range of values ​​from 0 T to 5.101 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.

[0080] 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, turns can be formed or printed directly onto the electronic board substrate 22. The turns can be circular or of different shapes, depending on the geometry of the quartz watch 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 quartz watch 100 is held in place by an imprint or counter-mold, ensuring that the relative position between the quartz watch 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 quartz watch 100 in contact with the magnetic field source 21, for example. Thus, there is no air gap between the quartz watch 100 and the magnetic field source 21, so that the quartz watch 100 is perfectly exposed to the varying magnetic field generated by the magnetic field source 21.

[0082] The mounting 25, clamping means 26, and electronic board substrate 22 can be made from materials that are non-conductive to electricity and / or "transparent" to magnetic fields, i.e., with a magnetic permeability close to 1, and / or materials non-magnetic. It is possible to use a mounting 25, clamping means 26 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 loop 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 quartz watch 100 (the quartz watch 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 quartz watch 100.

[0084] To perform a check on a particular quartz watch 100, one can plan to generate with the magnetic field source 21 the same magnetic field varying over time, and one can plan to iteratively measure the induced voltage: - without any 100 quartz watches, - with a reference 100 quartz watch; - with a 100 quartz watch 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 quartz watch 100 and the induced voltage with the quartz watch 100 to be checked, - on the one hand the induced voltage without any 100 quartz watch and the induced voltage with the reference 100 quartz watch and on the other hand the induced voltage without any 100 quartz watch and the induced voltage with the 100 quartz watch 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 quartz watch being tested allows the use of mathematical tools. Representations can be made on a Bode or Nyquist plot, which also allows for comparison between measured quartz watches. 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 quartz watch being tested and the magnetic response of the reference quartz watch. It is then possible to test / measure / authenticate a component of the quartz watch, and / or the quartz watch itself, based on the identified difference (we can verify that the difference is below a threshold, we can check for the absence or presence of a particular parameter or shape on the response curve, etc.).

[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 quartz watch 100 from Figures 2 to 5, installed near a second variant of a control device 20 for measuring the magnetic response of the quartz watch 100 to exposure to a varying magnetic field. Specifically, the quartz watch 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 quartz watch 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 quartz watches, - with a reference 100 quartz watch; - with a 100 quartz watch 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. It is also worth remembering that any coil can be characterized electrically by a resistance R and by a reactance X (function of the current angular frequency and the inductance L of the coil) forming the complex impedance Z.

[0096] In the presence of electrically conductive material in a quartz watch being tested, the changing electric field and induced currents cause a change in impedance compared to the case without the quartz watch. Specifically, the resistance R accounts for the internal Joule losses of the coil as well as the eddy current losses in the quartz watch being tested. The inductance L is related to the distribution of the electric field lines, which are modified by the presence of eddy currents in the quartz watch.

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

[0098] Figure 7 shows the quartz watch 100 from Figures 2 to 6, installed in a third variant of a control device for measuring the magnetic response of the quartz watch 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 case of the third variant, The 100 quartz watch will essentially be exposed to field lines passing through it and parallel to its back or its glass.

[0099] Figure 8 generally represents variants of the implementation of the magnetic field source 21, to expose the quartz watch 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 and second half-periods. The field draws power 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 can be understood that numerous constructions and arrangement possibilities are possible both for generating the variable magnetic field and for measuring it once the quartz watch 100 is placed near the magnetic field source. These include: - a transmitting coil, arranged at a certain relative position with respect to the quartz watch 100, - several transmitting coils, placed at various relative positions with the 100 quartz watch, - a receiving coil, arranged at a certain relative position with respect to the quartz watch 100, - several receiving coils, placed at various relative positions with the quartz watch 100, - a transmitting-receiving coil, arranged at a certain relative position with respect to the quartz watch 100, - several transmitting-receiving coils, placed at various relative positions with the quartz watch 100, - but we can also provide one or more magnetic field sensors, placed at various relative positions with the quartz watch 100. Regarding the aforementioned magnetic field sensor, one can expect a Hall effect sensor, a magnetoresistive sensor, a giant magnetoresistance, a SQUID type magnetometer (“Superconducting Quantum Interference Device >>”). [000103] Alternatively, a relative displacement can also be imposed between the quartz watch 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 quartz watch. If the quartz watch 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 quartz watch, taking into account the geometry and material of the quartz watch. The measurement of the reactances and / or impedances can then define the magnetic response, which allows the quartz watch 100 to be checked, measured, or authenticated. [000104] Figure 9 shows a graph representing the magnetic responses of several quartz watches (parts of watches) quartz), measured using the testing method according to the invention. Figure 9 shows normalized impedance curves, reconstructed after testing eleven identical quartz watch parts. Each quartz watch part was exposed to the same time-varying magnetic field with a frequency varying between 10 Hz and 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 quartz watch part. [000105] The quartz watch parts tested were all of the same model, but ten quartz watches from family A were found to be compliant, and an eleventh quartz watch from family B was found to be non-compliant, despite having an external visual appearance entirely similar to the compliant quartz watches. Specifically, the case material of the ten quartz watches in family A was a first grade of stainless steel, and the case material of the eleventh quartz watch in family B was a second grade of stainless steel. Also, the internal components present in the case of the ten quartz watches in family A during the test were compliant, and the internal components present in the case of the eleventh quartz watch in family B during the test were non-compliant, i.e., made of different materials and / or with some geometric differences from the quartz watches that could be identified. [000106] It can be noted that Figure 9 shows all the curves of the quartz watches in family A within a very tight group, whereas the curve of the eleventh quartz watch in family B is very different. It appears that the testing method, consisting of exposing a quartz watch to a varying magnetic field to measure a magnetic response, can be used to reliably test / measure / authenticate the quartz watch and / or one of its components. [000107] The controlled quartz watch can be a complete watch, a watch head (case and movement) as in Figure 5, but one can Also consider a watchmaking subsystem such as a movement, a case without a built-in movement, a bracelet..., or even a watchmaking component such as a case back, a bezel, a Lavet motor, ... Depending on the implementation, it may be necessary or practical to disassemble part of the quartz watch, such as removing the bracelet from the complete watch or removing the case back. 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 method for testing a quartz watch comprising at least one electrically conductive component, or a component of the quartz watch, the testing method comprising a testing phase with the steps of: - place the quartz watch, or at least a part of the quartz watch, in 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, - exposing the quartz watch, or at least a part of the quartz watch, to at least one predetermined magnetic field whose frequency varies over time, generated by the magnetic field source, - to measure, simultaneously with exposure to at least one magnetic field and using at least one magnetic field measuring device, at least one characteristic of the magnetic field in the vicinity of the quartz watch exposed to the predetermined magnetic field which varies over time, - deduce the magnetic response of the quartz watch from the measured characteristic of the magnetic field in the vicinity of the quartz watch, - compare the magnetic response of the quartz watch to a reference magnetic response.

2. A control method according to claim 1, wherein during the step of exposing the quartz watch to the predetermined and time-varying magnetic field, at least: - an amplitude, and / or - a frequency, and / or - an orientation, and / or - a spatial gradient, the magnetic field generated by the magnetic field source, is modified or variable over time.

3. A control method according to claim 2, wherein, during the step of exposing the quartz watch to the 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.

4. A control method according to claim 2 or 3, said quartz watch comprising an intercalating component: - arranged between said at least one electrically conductive component and said at least one magnetic field source and / or said at least one magnetic field measuring device, and - having a thickness of at least 1 mm and / or an electrical conductivity of at least 1.10 7S / m and / or a relative magnetic permeability greater than 50 and preferably a thickness of at least 2 mm and / or an electrical conductivity of at least 1.5 x 10 7 S / m and / or a relative magnetic permeability greater than 80, in which, during the stage of exposure of the quartz watch to the predetermined and time-varying magnetic field, the frequency of the predetermined magnetic field is 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.

5. A control method according to claim 2 or 3, said quartz watch comprising an intercalating component: - arranged between said at least one electrically conductive component and said at least one magnetic field source and / or said at least one magnetic field measuring device, and - having a thickness of no more than 2 mm and / or an electrical conductivity of no more than 1.10 7 S / m and / or a relative magnetic permeability of less than 50, and preferably a thickness of at most 1 mm or at most 0.5 mm and / or an electrical conductivity of at most 5.10 6 S / m and / or a relative magnetic permeability less than 5, in which, during the step of exposing the quartz watch to the predetermined and time-varying magnetic field, 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.

6. A control method according to any one of claims 2 to 5, wherein, during the step of exposing the quartz watch to the predetermined and time-varying magnetic field, the amplitude of the predetermined magnetic field is modified over time to obtain a powerful magnetic field, preferably according to a sinusoidal function.

7. A control method according to claim 6, wherein, during the step of exposing the quartz watch to the predetermined and time-varying magnetic field, the amplitude of the predetermined magnetic field 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.

8. A control method according to claim 6 or 7, wherein, during the step of exposing the quartz watch to the predetermined and time-varying magnetic field, a relative movement between the quartz watch and the magnetic field source is imposed.

9. A control method according to any one of claims 2 to 8, wherein, during the step of exposing the quartz watch to the 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.

10. A control method according to claim 9, wherein, during the step of exposing the quartz watch to the field 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 / second, and preferably at least 5 x 10 2 revolutions per second.

11. Control method according to any one of claims 1 to 10, wherein the step of exposing the quartz watch to the predetermined and time-varying magnetic field includes a step of electrically supplying at least one electrical coil, or even at least two electrical coils simultaneously or with a time offset.

12. Control method according to any one of claims 1 to 11, wherein the step of measuring at least one characteristic of the magnetic field in the vicinity of the quartz watch 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.

13. Control method according to any one of claims 1 to 12, in which the step of measuring at least one characteristic of the magnetic field in the vicinity of the quartz watch 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.

14. Control method according to any one of claims 1 to 13, in which the step of deducing the magnetic response of the quartz watch includes: - a comparison between a value of a magnetic field characteristic measured without the timepiece, and a value of the characteristic of the magnetic field measured in the vicinity of the quartz watch, 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 quartz watch, - an analysis phase with the construction of a Bode diagram, and / or a Nyquist diagram, and / or a Fourier series decomposition.

15. A control method according to any one of claims 1 to 14, comprising an initial reference-taking phase with the steps of: - place a reference quartz watch 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 quartz watch 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 quartz watch exposed to the predetermined magnetic field, which varies over time. - deduce a magnetic response of the reference quartz watch from the measured characteristic of the magnetic field in the vicinity of the quartz watch, - record the magnetic response of the reference quartz watch.

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