CH717002A2 - Timepiece fitted with a mechanical movement and a device for correcting a displayed time. - Google Patents

Abstract

The timepiece according to the invention, in particular a watch (2), is formed by a mechanical movement (4) incorporating a mechanical resonator (14). It comprises a time display (12) and a device (6) for correcting the displayed time, which is formed by a receiver (30) of an external correction signal which is supplied by an external electronic device 40. (in particular a mobile phone), a braking device (22A) of the mechanical resonator and an electronic control unit (28). The correction device (6) is designed to be able to correct the displayed time as a function of a temporal error (delay or advance) contained in the external correction signal. To do this, the correction device (6) is arranged so that the braking device can act on the mechanical resonator (14) during a correction period to vary the rate of the display drive mechanism. , so as to correct at least most of the time error of the displayed time. The invention also relates to the assembly formed by said timepiece (2) and the external device (40) comprising an external correction signal transmitter (52). The external device includes a photographic device (44), an image processing algorithm, and a time base (48).

Description

Technical area

In general, the present invention relates to a timepiece comprising a mechanical movement, a display of a real time which is driven by this mechanical movement, and a device for correcting this real time.

Technological background

In the field of mechanical watches, the conventional way of correcting the real time indicated by its display is to use the conventional stem-crown which is generally arranged to be able to act, in the pulled position, on a mobile of drive of the hour indicator and the minute indicator, thanks to a friction provided in the kinematic chain between these indicators and the escape wheel. Thus, to set a mechanical watch to real time, it is generally necessary for the user or a robot to pull the stem-crown and operate it in rotation to bring the hour and minute indicators into the respective desired positions, in particular. by a visual comparison with a reference clock, such as one finds for example in stations, or with a digital time given for example by a computer.

Summary of the invention

[0003] It can therefore be seen that in the field of timepieces fitted with a mechanical movement, in addition to ensuring precise operation of this mechanical movement, a real need exists for an effective system for correcting the real time. displayed by those timepieces comprising a mechanical movement. In particular, the present invention aims to be able to set the time precisely on a timepiece comprising a mechanical movement which causes the time to be displayed, preferably substantially at the exact real time which is given by a system. outside arranged to provide it (in particular a system connected to an atomic clock), without requiring that a user or a robot must actuate a stem-crown or another external control member of the timepiece to carry out itself a setting the display time. In the context of the invention, it is expected that the accuracy of the real time setting of a timepiece provided with a mechanical movement does not depend on a visual appreciation of the user who has to estimate when the various indicators concerned are in the correct respective positions.

The term "real time" is understood to mean the legal time of a given location, in which the timepiece and its user are generally located. Actual time is typically displayed in hours, minutes, and, if applicable, seconds. The real time can be indicated with some error by a timepiece, especially of the mechanical type. To indicate the legal time given with great precision in particular by / via a GPS system, a telephone network or a computer connected in particular to a server of the Internet network receiving the real time from a high precision clock, we will use the expression 'exact real time' in this text. This expression also applies to the real time given correctly by an electronic clock or an electronic time base, incorporated in a device external to the timepiece, which can be regularly synchronized on a high precision clock giving the legal time. In this text, real time will also be mentioned simply by the term 'the hour', in particular as regards the real time displayed by a timepiece.

To meet the aforementioned needs which have been present in the watchmaking field for many years, the present invention relates to a timepiece which comprises: a display of the real time; a mechanical movement formed by a drive mechanism for the display and by a mechanical resonator which is coupled to the drive mechanism so that its oscillation cycles the operation of this drive mechanism; a device for correcting the real time which is indicated by the display; and in which the device for correcting the displayed real time, incorporated in the aforementioned timepiece, is formed by: - a receiver of an external correction signal for the displayed real time, - an electronic control unit , and - a mechanical resonator braking device; the electronic control unit being arranged to be able to process the information contained in the external correction signal and to control the braking device as a function of this information. In addition, the device for correcting the displayed real time is arranged so that, when the external correction signal received by the timepiece requires a correction of the displayed real time, the braking device can act on the mechanical resonator during a correction period, to vary the rate of the drive mechanism, so as to effect at least the major part of the correction of the actual time displayed, preferably substantially all of this required correction .

By 'braking device' is generally understood any device capable of braking and / or stopping an oscillating mechanical resonator and / or of maintaining stationary (that is to say blocking) momentarily such a resonator. The braking device can be formed by one or more braking units (one or more actuators). In the case where the braking device is formed of several braking units, in particular two braking units, each braking unit is selected to act on the mechanical resonator in a specific situation relating to the required correction, in particular a first control unit. braking to correct a delay and a second braking unit to correct an advance (the second braking unit being advantageously arranged to be able to stop and momentarily block the resonator). By 'timing the operation of a drive mechanism of a display', one understands the fact of timing the movement of the moving parts of this mechanism when it is operating, in particular determining the speeds of rotation of these moving parts and so 'at least one indicator of the display. In the remainder of the text, when the term “resonator” without a specific qualifier is used, it is to designate a mechanical resonator. We will speak of an oscillating resonator to indicate that a resonator is considered in its activated state, in which it oscillates while being maintained, via an exhaust, by a source of mechanical energy.

In a preferred embodiment, the braking device is formed by an electromechanical actuator, arranged to be able to apply braking pulses to the mechanical resonator, and the electronic control unit comprises a device generating at least one frequency which is arranged so as to be able to generate a first periodic digital signal at a frequency FSUP. The electronic control unit is arranged to supply the braking device, each time the external correction signal received via the reception unit corresponds to a delay in the displayed time which it is intended to correct, a first signal control derived from the first periodic digital signal, during a first correction period, to activate the braking device so that this braking device generates a first series of periodic braking pulses which are applied to the mechanical resonator at said frequency FSUP, the number of periodic braking pulses in said first series and therefore the duration of the correction period being determined by the delay to be corrected. The frequency FSUP is provided and the braking device is arranged so that said first series of periodic braking pulses at the frequency FSUP can generate, during the first correction period, a first synchronous phase in which the oscillation of the mechanical resonator is synchronized (on average) on a correction frequency FScor which is greater than a reference frequency F0c provided for the mechanical resonator.

[0008] According to a preferred variant, in which the watch movement comprises an escapement associated with the resonator, the frequency FSUP and the duration of the braking pulses of the first series of periodic braking pulses are selected so that, during said first phase synchronously, the braking pulses of said first series each intervene outside a coupling zone between the oscillating resonator and the escapement.

[0009] In a particular embodiment, the timepiece comprises a device for blocking the mechanical resonator. Then, the electronic control unit is arranged to be able to supply the blocking device, when the external correction signal received via the reception unit corresponds to an advance in the displayed time which it is intended to correct, a signal control which activates the blocking device so that it blocks the oscillation of the mechanical resonator during a correction period determined by the advance to be corrected, so as to stop the operation of the drive mechanism during this correction period. The correction / blocking period normally has a duration substantially equal to the corresponding advance to be corrected.

In general, the correction of the time displayed by the display relates to an error detected in this time displayed by an external electronic device arranged to be able to supply the timepiece with the external correction signal. In a specific case, the correction of the displayed time relates to a seasonal change in the time, or even to a change of time zone.

The invention also relates to an assembly formed by a timepiece according to the invention and an external device comprising an emitter of said external correction signal. The external device includes: a photographic device comprising a photographic sensor formed by an array of photo-detectors, an image processing algorithm which is designed to be able to determine the position of at least one determined hand of the display of the timepiece in an image taken by the photographic device, and a time base capable of providing the exact real time.

In a preferred embodiment, the external device further comprises an algorithm for calculating a temporal error between a first temporal datum, displayed by the display at a given instant and detected by the external device via its photographic sensor and its image processing algorithm, and a second temporal datum corresponding to the first temporal datum and supplied substantially to said given instant by the time base. When provision is made to correct the calculated time error, the external correction signal supplied by the device external to the timepiece includes information relating to this time error.

Brief description of the figures

The invention will be described below in more detail with the aid of the accompanying drawings, given by way of non-limiting examples, in which: Figure 1 shows, in part schematically, a first embodiment of an assembly according to the invention comprising a timepiece, according to a first embodiment, which is provided with a mechanical movement, a display of the time and a device for correcting the displayed time, as well as an external electronic device, according to a first embodiment, which is arranged to be able to communicate with the correction module; FIG. 2 schematically represents a variant of the device for correcting the timepiece according to the first embodiment of FIG. 1; Figures 3 and 4 show, during a correction made by a series of periodic braking pulses, the evolution of the oscillation frequency of a mechanical resonator during a period of correction of an advance, respectively of a period of correction of a delay in the time indicated by a display of the timepiece considered, and this for the case of a relationship between the correction frequency and the reference frequency relatively close to the value '1'; Figure 5 shows, in the case of a relatively high ratio between the correction frequency and the reference frequency, the oscillation of a mechanical resonator at the start of a period of correction of a delay by a series of periodic braking pulses, this correction period having an initial transient phase; FIG. 6 shows, during a correction of a delay operated by a series of periodic braking pulses, a few periods of oscillation of a mechanical resonator during a synchronous phase for two different synchronization frequencies; Figure 7 A shows, for a braking frequency corresponding to an alternating braking pulse of the oscillation of a mechanical resonator, several curves of the maximum relative synchronization frequency as a function of the amplitude of the free oscillation of the resonator and its quality factor; Figure 7B shows, for a braking frequency corresponding to a braking pulse per period of oscillation of a mechanical resonator, several curves of the maximum relative synchronization frequency as a function of the amplitude of the free oscillation of the resonator and its quality factor; Figure 8 is a graph giving, for a given setpoint frequency, approximately the possible correction frequency ranges, to correct a delay in the time display using short periodic braking pulses, as a function of several braking frequencies selected for the braking pulses; Figure 9 is a graph giving, for a given setpoint frequency, approximately the possible correction frequency ranges, to correct an advance in the time display using short periodic braking pulses, as a function of several braking frequencies selected for the braking pulses; FIG. 10 partially shows a second embodiment of a timepiece according to the invention; FIG. 11 partially shows a third embodiment of a timepiece according to the invention; FIG. 12 schematically represents a fourth embodiment of a timepiece according to the invention; Figure 13 shows a second embodiment of an assembly according to the invention comprising a timepiece according to the invention and an external electronic device, according to a second embodiment, serving as a box and charging station for the timepiece; Fig. 14 schematically shows the arrangement of electronic elements and functional units in the external electronic device of the second embodiment; FIG. 15 schematically represents a fifth embodiment of a timepiece according to the invention, which can form the assembly according to the second embodiment; Figure 16 shows, in part schematically, a sixth embodiment of a timepiece according to the invention; and Figures 17 and 18 show the oscillation of the mechanical resonator during a delay correction period respectively for two variant embodiments of the braking device of the timepiece of Figure 16.

Detailed description of the invention

With reference to Figures 1 and 2, a first embodiment of a timepiece according to the invention will be described below, as well as a first embodiment of an assembly according to the invention comprising a timepiece according to the invention and an external electronic device formed by a portable telephone.

The timepiece 2 comprises a mechanical movement 4, an analog time display 12, a mechanism 10 for driving this display and a device 6 for correcting the time indicated by the display. The mechanical movement comprises a barrel 8 forming a source of mechanical energy for the drive mechanism 10 which is formed by a gear 11, in kinematic connection with the display, a mechanical resonator 14, formed by a balance 16 associated with a hairspring 15, and an escapement 18 coupling this resonator to the drive mechanism so that the oscillation of the resonator rates the operation of this drive mechanism. The analog display 12 is formed by a dial 32, comprising indexes 36 forming a graduation for the display of the real time, and by hands 34 comprising an hour hand, a minute hand and a seconds hand. The needles have different shapes, in particular different lengths and / or widths. Preferably, the indexes are arranged so as to be able to visually determine the "12 o'clock" position for a 12-hour hour turn (or "24 hour" for a 24-hour hour turn). In the case shown, the angular position of '12H' is defined by two parallel and substantially radial bars, while the angular positions of the other hours are defined by a single bar.

Various variants can be provided to make it possible to determine at least one angular position of the display corresponding to a number of minutes and / or seconds determined on the graduation provided for the display of minutes and / or seconds. Note that the graduation is not necessarily visible. Indeed, for example, it suffices to know that we are in the presence of a 12-hour turn of hours and that the angular position '12H' is provided on a given and identifiable axis of the timepiece, and to have a mark visible on the display side making it possible to determine the angular position 12H on this given axis, and therefore any other angular position corresponding to any hour, any minute and / or any second. For example, the dial may have a pattern making it possible to define an orientation of the dial or the dial comprises an additional sign defining a determined angular mark corresponding to a particular position of the planned graduation. Such an additional sign can also be placed on a flange surrounding the dial or on the bezel of the watch case in which the mechanical movement 4 is incorporated. It should be noted that the angular mark can be simply given by the shape of the case defining a determined axis which can be identified visually or by the winding crown. It will be noted that the present invention is not limited to an analog display of the real time, but can also relate to other displays of the real time, for example a display with a 'jumping hour' and / or in particular a 'jumping minute'. The display is therefore not limited to a system with hands having an almost continuous advance. The invention can therefore also be applied in particular to a system with discs or rings and in particular to a display provided through at least one aperture provided in the dial.

The correction device 6 comprises a receiver 30 of an external signal SExtde correction for the time displayed by the display 12 and an electronic unit 28 for controlling the displayed time which is arranged to be able to process the information. contained in the external correction signal SExt and generate in response at least one internal correction signal relating to a correction of the displayed time, which is determined by the external correction signal SExt, that is to say by the information contained in this external correction signal. The timepiece is arranged so as to allow correction of the time indicated by its display as a function of the external correction signal SExt that it receives. To correct the displayed time, the correction device generally comprises a device for braking the mechanical resonator. In a main variant, the braking device is formed by an electromechanical actuator, for example an actuator of the piezoelectric type 22A. Then, the braking device is controlled by an electronic control unit 28 which transmits to it a control signal SCmd to control its supply circuit so as to temporally manage the application of a mechanical braking force to the mechanical resonator 14. In general, the correction device is arranged so that the braking device can act, each time the external correction signal SExtreeceived by the timepiece requires a correction of the displayed time, on the mechanical resonator 14 during a correction period for varying the rate of the drive mechanism 10 so as to correct at least most of the time displayed.

In the variant shown, the actuator 22A comprises a braking member which is formed by a flexible blade 24, which has on two opposite surfaces (perpendicular to the plane of Figure 1) respectively two piezoelectric layers which are each coated with 'a metallic layer forming an electrode. The piezoelectric actuator comprises a supply circuit 26 making it possible to apply a certain voltage between the two electrodes so as to apply an electric field through the two piezoelectric layers, which are arranged so as to bend the blade 24 in the direction of the serge 20 of the balancer 14, when a voltage is applied between the two electrodes, so that the end part of the blade, forming a movable brake shoe, can press against the outer circular surface of the serge and thus exert a force mechanical brake on the mechanical resonator. It will be noted that the voltage can be variable, in order to vary the mechanical braking force and therefore the mechanical braking torque applied to the balance. Regarding the braking device, reference may be made to document WO 2018/177779 for various alternative arrangements of such a braking device in a mechanical watch movement. In a particular variant, the braking device is formed by a blade actuated by a magnet-coil system. In another particular variant, the balance comprises a central shaft which defines or which carries a part other than the rim of the balance, for example a disc, defining a circular braking surface. In the latter case, a shoe of the braking member is arranged so as to exert pressure against this circular braking surface during the momentary application of a mechanical braking force.

The reception unit 30 is preferably a contactless receiver, for example a sensor of optical signals encoded according to a given communication protocol, a 'Bluetooth' receiver (preferably 'Bluetooth Low Energy': BLE) or a receiver for short-distance wireless communication known by the acronym NFC. Note that in these last two cases, it is in practice communication units making it possible to receive and send signals according to a predefined standard. The reception unit 30 is designed to be able to demodulate the external correction signal SExt and provide the electronic control unit 28 with a digital correction signal Scor corresponding to the demodulated signal SExt.

A preferred variant of a first embodiment of an assembly according to the invention comprises a timepiece according to the invention and a mobile telephone 40 in which is installed at least one time correction application for implementing the present invention, in particular for detecting an error in the time indicated by the display of the timepiece and supplying an external correction signal SExt corresponding to this timepiece. The mobile phone includes its own resources which are used by the time correction application, in particular a power source 42, a time base 48 giving the exact real time, and a photographic device comprising a photographic sensor formed. a matrix of photo-detectors. The time base can be formed by an electronic clock which is regularly synchronized with an exact real time provided by the telephone network or by WIFI and / or by a GPS receiver. Thus, the time base provides a reference time which can be very precise, synchronized for example on an atomic clock giving the exact real time of the place where the mobile telephone and its user are located. The photographic device 44 has a sensor formed by a matrix of pixels making it possible to take a precise image of the analog display 12.

The time correction application installed in the mobile phone comprises an image processing algorithm 46 or the application is designed to be able to use such an algorithm which is the subject of a specific application for processing. 'images installed in the mobile phone or in a server to which the mobile phone has access, in particular via the Internet. The image processing algorithm is designed to be able to determine the position of at least one determined needle of the analog display 12 in an image taken by the photographic device 44, that is to say the position of this needle relative to a graduation provided for its display, this graduation being able to be reduced to a single visual mark making it possible to determine a particular position of a virtual graduation, as indicated above. In a two-hand display (hours and minutes), at least the angular position of the minute hand will be determined relative to a mark on the dial 32 or to another part of the timepiece visible from the display side. , used to determine the displayed minute relative to the minute scale (visible or not). In a three-hand display (hours, minutes and seconds), at least the angular position of the minute hand and that of the seconds hand will be determined. Reference will also be made to the preceding passage relating to various variants which may be provided for determining at least one angular position of the display.

Next, the time correction application comprises an algorithm for calculating a temporal error between a first temporal datum, indicated by the display at a given instant and detected by the external device, in particular the telephone portable 40, via its photographic sensor and its image processing algorithm, and a second temporal datum corresponding to the first temporal datum and supplied to said instant given by the time base 48. As indicated above, the first temporal datum can be the displayed minute, displayed minute and second or actual displayed time (hours, minutes and seconds).

Finally, the mobile telephone 40 comprises a transmission unit (a transmitter) of the external correction signal SExt. The transmission unit is of the same type as the reception unit (of the receiver) of the timepiece, in particular of the optical type (photodiode) or of the radio type (for example a BLE or NFC communication unit). The time correction application comprises a function making it possible to code the result supplied by the algorithm for calculating a temporal error in a format specific to the transmitting unit 52 for sending the external correction signal. SExt. Thus, when provision is made to correct the detected temporal error, the external correction signal supplied by the device external to the timepiece comprises information relating to this temporal error. Preferably, the information transmitted is the temporal error detected in the most precise unit that the time display allows, generally the second or the tenth of a second. It will be noted that the decision whether or not to correct the display can be taken by the application in the portable device or by the electronic control unit in the timepiece. If the detected error is zero, it is obvious that no correction is required. If the detected error is not zero but small, for example less than five seconds, it is possible in a variant to decide that this error does not require any correction. In other words, at least in a given operating mode, it is possible to define a range of values for the detected time error for which no display correction is provided.

In another variant, provision is made for the algorithm for calculating a temporal error described above to be incorporated into the timepiece. In this case, the external correction signal SExt contains the first time data and the second time data which are then processed by the algorithm for calculating a time error which is integrated in the electronic control unit located in the room. watchmaking. In one embodiment where the timepiece comprises an internal electronic clock, in particular for an electronic module of the 'Fitness' type, the time of the time base of the mobile telephone can also be transmitted, as additional information, to the timepiece. Indeed, the second temporal datum relates to the instant of the image capture and does not correspond exactly to the instant of transmission of the external correction signal, so that a complementary datum relating to a third temporal datum is advantageous if it is desired to provide, for an additional function, an exact time to an internal electronic clock of the timepiece.

Figure 2is shown the correction device of the timepiece according to the first embodiment. The receiving unit 30A is formed by a sensor of an optical signal. This optical sensor comprises at least one element of the phototransistor type. In one variant, it forms part or consists of a solar cell forming an energy recuperator 54 and serving to supply an electricity accumulator 56. In another variant, the optical sensor 30A is a separate element from the energy recuperator. energy 56 which serves as an energy source for a supply circuit 58 of the correction device. The energy recuperator can be formed by various types of devices known to those skilled in the art, for example a recuperator of magnetic, light or heat energy. In a variant, the magnetic energy recuperator is arranged to receive energy from an external magnetic source making it possible to recharge the electricity accumulator without electrical contact. In another advantageous variant, the energy recuperator is formed by a magnet-coil system making it possible to recover a little energy from the oscillation of the mechanical resonator of the timepiece and therefore of the barrel maintaining this oscillation. In this last variant, at least one magnet is arranged on the oscillating element of the resonator or on the support of the resonator and at least one coil respectively on said support or on said oscillating element, so that the major part of the magnetic flux generated by the magnet passes through the coil when the resonator oscillates within its useful operating range. Preferably, the magnet-coil coupling is provided around the neutral position (rest position) of the resonator. In another variant, in which the mechanical movement is an automatic movement, the oscillating mass is used to drive a micro-generator producing electricity which is stored in the accumulator. Note that the energy recuperator can also be hybrid, that is to say formed of several different units, in particular of the wireless / contactless type, which are provided to recover various energies from various energy sources and transform these various energies into electrical energy.

The electronic control unit 28A controls a device 22 for braking the resonator 14, in particular an electromechanical actuator 22A shown schematically in Figure 1. Other types of actuators for temporarily applying a braking force to the resonator mechanics can be expected. As an option, the electronic control unit comprises a circuit 68 for detecting the level of electrical energy available, this detection circuit supplying a signal SNE to a control logic circuit 60 to give it information relating to the level of electrical energy. available, so that this logic circuit can know whether the correction module has sufficient energy before launching an operation to correct the displayed time. If this is not the case, the following various options are possible: 1) The timepiece has a transmitter allowing direct indication to the user that the accumulator must be recharged to enable a complete correction of the displayed time, for example via an optical or acoustic signal generated by the transmitter. The timepiece does not perform any correction until the level of electrical energy is sufficient for a complete correction. 2) The timepiece has a transmitter, in particular a BLE or NFC communication unit or an optical transmitter formed of at least one light-emitting diode, making it possible to indicate to the mobile phone 40 that the battery must be recharged for allow a complete correction of the displayed time. The mobile phone can then indicate this information to the user on its electronic display. In a variant, the timepiece does not perform any correction as long as the level of electrical energy is not sufficient for a complete correction. In an advantageous variant, the mobile telephone directly activates a function of recharging the electricity accumulator 56 via the energy recuperator 54 or another energy recuperation device specific to a transfer of energy from the mobile telephone, by example by magnetic induction. 3) The timepiece only performs a partial correction of the displayed time by using the energy available in the accumulator 56 and, preferably, informs the mobile telephone, via a transmitter arranged in the timepiece, of the that the correction made will be only partial and possibly the remaining error that the logic circuit 60 can calculate. 4) The timepiece does not make any corrections and does not transmit any information (simple variant with a 'silent' timepiece).

In the absence of an electrical energy management as indicated above, the timepiece can begin a required correction operation if the available electrical voltage is sufficient and perform this correction operation as long as the electric voltage supplied by the supply circuit 58 is sufficient. In an advantageous variant, provision is made to put the correction device in a standby mode when no operation to correct the displayed time is provided, so as to save the electrical energy available in the accumulator 56. Various parts of the correction module can be activated, as needed, only during different periods. In the context of another embodiment, we will return below to the management of the electrical power supply to the correction device according to the invention.

The electronic control unit 28A, incorporated in the first embodiment of the timepiece 2, comprises a control logic circuit 60, which receives the digital signal of Scor correction supplied by the receiver 30A of the external signal correction SExt, and a generator device 62 of a periodic digital signal having a given frequency FSUP (the generator device 62 is also called a “frequency generator” or simply “generator” at the frequency FSUP). Depending on whether the time error TErr to be corrected corresponds to a delay or an advance in the time display, the control logic circuit 60 generates respectively either two control signals S1R and S2R, which it supplies respectively to the frequency generator 62 and to a time counter 63 ('timer'), that is to say a control signal SA which it supplies to a time counter 70. The time counters 63 and 70 are programmable and are used to measure a planned correction period, respectively a period PRcor for the correction of a delay and a period PACor for the correction of an advance. By definition, an advance corresponds to a positive error and a delay corresponds to a negative error. As indicated previously, the logic circuit receives either the temporal error TErr to be corrected (preferred variant), or a time displayed by the timepiece at a given instant and the corresponding exact real time supplied by a time base of the electronic device. external. In the second case, it itself calculates the temporal error TErr.

We will first explain the arrangement of the electronic control unit 28A to correct a delay detected in the display of the time, and only subsequently the arrangement of this unit to correct an advance.

In the case of a negative error corresponding to a delay, provision is made, according to a first mode of correcting a delay, to generate a series of periodic braking pulses at a frequency FSUP, these braking pulses periodic being applied by the braking device 22, in particular by the actuator 22A to the oscillating resonator. To do this, the control logic circuit 60 activates the frequency generator 62 via the signal S1R and the time counter 63 which counts or counts down a time interval corresponding to a correction period PRCord the duration (the value) is determined by the circuit logical (by definition, the expression 'time counter' includes a time counter at a given time interval and also a time count down to zero from this given time interval which is initially introduced into this time count down).

In the variant shown, when the frequency generator is activated, it supplies a periodic digital signal SFS, at the frequency FSUP, to another time counter 64 (timer at a value Tp corresponding to a duration selected for the pulses of periodic braking). The outputs of the timers 63 and 64 are supplied to an 'AND' ('AND') logic gate 65 which outputs a periodic activation signal SC1 to periodically activate the braking device 22, during the correction period PRcor provided, via an “OR” logic gate 66 or any other switching circuit making it possible to transmit the periodic activation signal SC1 to the braking device. The periodic activation signal SC1forms the control signal SCmd in the case of a correction of a delay detected in the time displayed by the timepiece. Thus, the braking device applies periodic braking pulses to the mechanical resonator at the frequency FSUP during a correction period PRC The duration (value) depends on the delay to be corrected. In general, the braking pulses have a dissipative character because part of the energy of the oscillating resonator is dissipated during these braking pulses. In a main embodiment, the mechanical braking torque is applied substantially by friction, in particular by means of a mechanical braking member exerting a certain pressure on a braking surface of the resonator, preferably a circular braking surface, such as explained previously during the description of the timepiece 2 with reference to Figure 1.

Preferably, as for the variant shown in Figure 1, the system formed of the mechanical resonator and the braking device of this resonator is configured so as to allow the braking device to start, in the useful operating range of the oscillating resonator, a mechanical braking pulse at substantially any time during the period of natural oscillation of the oscillating resonator. In other words, one of the periodic braking pulses can start at substantially any angular position of the oscillating resonator, in particular the first braking pulse occurring during a correction period.

According to the teaching given by document WO 2018/177779 already cited above, it is possible to precisely regulate the average frequency of an oscillating resonator by continuously applying periodic braking pulses to it at a corresponding braking frequency FFR advantageously twice the setpoint frequency FOc divided by a positive integer N, i.e. FFR = 2F0c / N. The braking frequency FFRis proportional to the setpoint frequency F0c for the mechanical resonator and depends only on this setpoint frequency as soon as the positive integer N is given. We learn from document WO 2018/177779 that, after a transient phase occurring at the start of the activation of the braking device applying the periodic braking pulses to the braking frequency FFR, a synchronous phase is established during which the oscillation of the braking device. The mechanical resonator is synchronized, on average, on the setpoint frequency F0c, provided that the braking torque applied by the braking pulses and the duration of these braking pulses are selected so that the braking pulses intervene, during the synchronous phase, when the mechanical resonator passes through extreme positions of its oscillation, i.e. the reversal of the direction of the oscillation movement occurs during each braking pulse or at the end of each braking pulse. This latter situation occurs in the advantageous, in particular safer, case where the mechanical resonator is stopped by each braking pulse and then remains blocked by the braking device until the end of this braking pulse.

Although not very interesting, document WO 2018/177779 indicates that synchronization can also be obtained for a braking frequency FFR greater than twice the setpoint frequency (2F0), in particular for a value equal to M-FO with M being an integer greater than two (M> 2). In a variant with FFR = 4 · F0, there is just a loss of energy in the system with no effect during the synchronous phase, because every other pulse occurs at the neutral point of the resonator; which is disadvantageous. For a higher FFR braking frequency, the pulses in the synchronous phase which do not intervene at the extreme positions cancel their effects two by two. We therefore understand that these are theoretical cases of little practical interest. It will be noted that other braking frequencies can lead to synchronization of the resonator on the reference frequency, but the conditions for implementing the regulation method are much more delicate and difficult to implement.

As part of the development which has led to the present invention, it has been highlighted that the remarkable phenomenon highlighted in document WO 2018/177779 can be used not only to continuously synchronize a resonator on its frequency setpoint, but also to vary in a determined manner the oscillation frequency of a resonator in two frequency ranges located respectively below and above its setpoint frequency; that is to say that it is possible to impose a determined average frequency on a mechanical resonator which is different from its setpoint frequency, higher or lower, by applying periodic braking pulses which can synchronize this resonator on a frequency different from the reference frequency but sufficiently close to the latter to allow the establishment of a synchronous phase between the oscillating resonator and the braking device generating the braking pulses at a frequency selected for this purpose, while maintaining the resonator oscillating in a functional regime to pace the movement of the timepiece. The present invention proposes to use this remarkable discovery to perform a correction of the time displayed by a timepiece by varying the rate of the mechanical watch movement considered, that is to say by varying the frequency of the resonator which cycles. the operation of the display drive mechanism of the timepiece in question during a given correction period.

In particular, in the first embodiment of the electronic control unit described here, provision is made to correct a delay detected in the displayed time according to a first mode of correcting a delay in which one synchronizes, during a correction period PRCor, the resonator oscillating on a correction frequency FSCorqui is greater than the reference frequency F0c. It has been demonstrated in the context of the development which led to the present invention that, in a similar manner to the case of synchronization on the reference frequency, the best results are obtained, for a correction frequency higher or lower than the frequency of setpoint, when the braking frequency FBra is selected, for a given correction frequency Fcor, so as to satisfy the following mathematical relation: FBra = 2 · FCor / N, where N is a positive integer.

Thus, the periodic braking pulses are applied to the mechanical resonator at a braking frequency FBrac advantageously corresponding to twice the correction frequency FCordivized by a positive integer N, preferably low. This relation is valid for a correction frequency FCor = FSCor which is greater than the reference frequency and also for a correction frequency FCor = FlCor which is less than the reference frequency (first mode of correction of an advance which will occur thereafter in another embodiment of a timepiece according to the invention). The braking frequency FBra is therefore proportional to the planned correction frequency FCoret only depends on this correction frequency as soon as the positive integer N is selected. By “synchronization on a given frequency” one understands an average synchronization on this given frequency. This definition is important for a number N greater than two. For example, in the case N = 6, there is only one oscillation period out of three which undergoes a variation in its duration, relative to the reference period TOc = 1 / FOc (in fact relative to the natural oscillation period / free T0 = 1 / F0), via a time phase shift generated by each braking pulse in the oscillation of the resonator.

It will be noted that, as in the case of synchronization on the setpoint frequency, other braking frequencies can make it possible to obtain, under certain conditions, synchronization on a desired correction frequency, but the selection of 'a braking frequency FBra = 2-FCor / N makes it possible to obtain synchronization on the frequency Fcor more efficiently and with more stability. In general, the mathematical relationship between the braking frequency and the correction frequency is FBra = (p / q) · FCor with p and q two positive integers and the number q advantageously greater than the number p. The person skilled in the art can experimentally establish a list of the fractional numbers p / q which are appropriate and under which conditions (in particular for which braking torque).

It will be noted that the braking pulses can be applied with a constant force torque or a non-constant force torque (for example substantially in a Gaussian or sinusoidal curve). By "braking pulse" is understood the momentary application of a torque of force to the resonator which brakes its oscillating member (balance), that is to say which opposes the oscillating movement of this oscillating member. In the case of a variable torque, the duration of the pulse is generally defined as the part of this pulse which has a significant force torque to brake the resonator, in particular the part for which the force torque is greater than the half of the maximum value. It will be noted that a braking pulse can exhibit a strong variation. It can even be chopped and form a succession of shorter pulses. In general, the duration of each braking pulse is expected to be less than half of a setpoint period T0c for the resonator, but it is advantageously less than a quarter of a setpoint period and preferably less than T0c / 8 .

AuxFigures 3 and 4 are shown, for a mechanical resonator having a setpoint frequency F0c = 4 Hz and having an oscillation 72, respectively a first series of periodic braking pulses 74 applied to the resonator at a frequency FINF = 2 · FlCoravec Flcor = 0.99975 F0c = 3.999 Hz, for the case of a natural frequency F0 = 4.0005 Hz, and a second series of periodic braking pulses 76 applied to the resonator at a frequency FSUP = 2 · FSCor with FSCor = 1.00025 · F0c = 4.001 Hz, for the case of a natural frequency FO = 3.9995 Hz. The graphs below in Figures 3, 4 show the evolution of the oscillation frequency of the resonator during a correction period, which is defined as the period during which the braking pulses at the frequency FINF or FSUP are applied to the resonator. Curve 78 shows the evolution of the oscillation frequency of the mechanical resonator during the application of the first series of periodic braking pulses 74 for a correction of an advance detected in the displayed time, the braking frequency FINF leading to a correction frequency FlCor, given by the synchronization frequency, which is lower than the reference frequency F0c (first mode of correction of an advance). Curve 80 shows the evolution of the oscillation frequency of the mechanical resonator during the application of the second series of periodic braking pulses 76 for a correction of a delay detected in the displayed time, the braking frequency FSUP leading to a correction frequency FSCor, given by the synchronization frequency, greater than the reference frequency (first mode of correction of a delay).

The very short correction period in Figures 3 and 4 was taken to be able to show a complete correction period while having a representation of the oscillation of the resonator and of the periodic braking pulses which is clearly visible on the graph giving the angular position of the resonator as a function of time. Indeed, in a few seconds, the possible correction is relatively small, in practice less than a second. For the correction frequencies chosen in Figures 3 and 4, the correction is therefore very small. Thus, if the natural frequencies (natural / free frequencies) of the oscillating resonator are here in the standard for a mechanical watch, since they correspond to a daily error of approximately 10 seconds per day (advance, respectively delay), the frequencies of correction are given purely by way of example and are much closer to the reference frequency than the correction frequencies which are generally provided for the implementation of the first mode of correcting an advance or a delay. In conclusion, Figures 3 and 4 are given only schematically to show in general the behavior of the oscillating resonator when subjected to a series of periodic braking pulses at a correction frequency close to the setpoint frequency, but different of the latter, and in the case of a natural frequency leading to a classical time drift. More detailed and precise considerations relative to the possible correction frequencies will be explained below.

In the two graphs showing the frequency curves 78 and 80, at the start of the correction period, a transient phase PHTrau is observed during which the frequency varies before stabilizing at the frequency FlCor, respectively FSCor during a synchronous phase PHSyn which follows the transient phase. In the two cases shown, the relatively short transient phase PHTrest (less than 2 seconds) and the change in frequency takes place in the direction of the desired correction frequency. In the two cases shown, the average correction per unit of time during the transient phase is approximately equal to that which occurs during the synchronous phase. However, it will be noted that the transient phase can be longer, for example from 3 to 10 seconds, and the evolution of the frequency during the transient phase varies from case to case so that the average correction is variable and not determined. , but it remains practically low. Reference may be made to FIGS. 9 to 11 of document WO 2018/177779 where the transient phases for synchronizing the resonator on the reference frequency F0c, from a close but different natural frequency, are longer. It will be noted that in FIG. 10 of this document, while the setpoint frequency is greater than the natural frequency of the resonator, the oscillation frequency begins by decreasing at the start of the transient phase before increasing to finally exceed the frequency natural and stabilize at the setpoint frequency.

The duration of the transient phase and the evolution of the frequency during this transient phase depend on various factors, in particular the braking torque, the duration of the pulses, the initial amplitude of the oscillation, and the instant at which the first braking pulse occurs in an oscillation period. It is therefore difficult to control the time difference resulting from a transient phase relative to the reference frequency. For example, if FCor = 1.05F0c = 4.2 Hz and the transition phase lasts a maximum of 10 seconds, and if it is assumed that the average frequency during this transition phase is equal to F0c , then the absolute time difference with respect to FCor is at most equal to half a second. This uncertainty therefore generates a small error in the correction generated during a correction period, but it is not negligible. We will see below a solution to avoid such an error. In the first embodiment of the electronic control unit, there is therefore a small possible error in the correction obtained if we determine (the duration of) the correction period PRConly on the basis of the time error TErr to be corrected, in defining this correction period as the period during which a series of periodic braking pulses are applied to the resonator at the expected braking frequency, and assuming that the oscillation frequency during the correction period is that of the synchronization frequency.

The synchronization frequency determines the correction frequency. By definition, the correction frequency Fcor is equal to the synchronization frequency. It will be noted that, in the synchronous phase of the correction period, the duration of the braking pulses must be sufficient for the braking torque applied to the resonator to allow it to stop (passage through an extreme angular position, defining its instantaneous amplitude) during or at the end of each braking pulse. In the case of a synchronization frequency greater than the reference frequency for correcting a delay, the time interval during which the resonator remains stopped during a braking pulse decreases the possible correction per unit of time, so that it is preferable to limit this time interval, taking into account a certain safety margin, in order to have a shorter correction period thanks to a higher synchronization frequency. It should be noted that the frequency of the braking pulses, the sustaining energy supplied to the resonator at each alternation of its oscillation and the value of the braking torque intervene in the time interval necessary to stop the oscillating resonator. For a given braking frequency and the resulting correction frequency, the person skilled in the art will know how to determine, in particular experimentally or by simulations, a braking torque and a duration for the braking pulses so as to optimize the braking system. For reference frequencies between 2 Hz and 10 Hz, braking torques between 0.5 µNm and 50 µNm and braking pulse durations between 2 ms and 10 ms are generally suitable for the correction frequencies that it is practically advantageous to use (these ranges of values being given by way of non-limiting examples).

Starting from the hypothesis mentioned above, namely that the synchronization frequency occurs over the entire correction period PRCor, it is possible to determine the value of the correction period to be provided on the basis of the time error TErrà to correct, of the reference frequency F0c and of the correction frequency FCor; and as the synchronization frequency determines the correction frequency which is equal to it, it is also possible to determine the value of the correction period to be provided on the basis of the time error TErr to be corrected, the setpoint frequency F0c and the frequency braking will do. By definition, an advance in the time display corresponds to a positive error while a delay corresponds to a negative error. We obtain the following mathematical relations to determine the value of the correction period: PCor = TErrF0c / (F0c - FCor) = 2TErrF0c / (2F0c - NFBra)

In the first mode of correcting a delay (negative error), the correction frequency FCor = FSCorest greater than F0c, so that PCor is indeed positive. In this case the braking frequency FBra = FSUP. We then have the relation: PRCor = TErrF0c / (F0c - FSCor) = 2TErrF0c / (2F0c - NFSUP)

In the first mode of correcting an advance (positive error), the correction frequency Fcor = Flcor is less than F0c, so that Pcor is indeed positive. In this case the braking frequency FBra = FINF. We then have the rotation: PAcor = TErr · F0c / (F0c - Flcor) = 2TErr · F0c / (2F0c - N · FINF)

In an alternative embodiment, the external electronic device (mobile telephone 40) has in memory or receives from the timepiece considered the setpoint frequency for the mechanical resonator of this timepiece and the higher frequency provided for correct a delay (possibly according to ranges of values for this delay). Thus, in this variant, the time correction application which is implemented in the external electronic device can determine the value of the correction period PRCor and communicate this information to the timepiece via the external correction signal SExt. In this variant, the electronic control unit of the timepiece does not need resources to calculate the value of the correction period on the basis of the time error TErr to be corrected.

Following the general discussion relating to a correction of the rate of a mechanical timepiece obtained by a series of periodic braking pulses applied to its resonator, one can return to the first embodiment of the part clockwork according to the invention. The electronic control unit 28A (Figure 2) is arranged to supply the braking device, each time the external correction signal SExtreeceived by the receiving unit of the timepiece 2 corresponds to a delay in the hour displayed that it is intended to correct, a control signal SC1 derived from the periodic digital signal SFS supplied by the frequency generator 62, during a correction period PRCor, to activate the braking device 22 so that this braking device generates a series periodic braking pulses which are applied to the resonator at the frequency FSUP. Since (the duration of) the correction period is determined by the delay to be corrected, the number of periodic braking pulses in the series of periodic braking pulses is therefore also determined by the delay to be corrected. The frequency FSUP is provided and the braking device is arranged so that each series of periodic braking pulses at the frequency FSUP can generate, during the corresponding correction period, a first synchronous phase in which the oscillation of the resonator is synchronized. (by definition 'synchronized on average') on a correction frequency FScor which is greater than the reference frequency F0c provided for the mechanical resonator.

With reference to Figures 5 to 10, a few observations relating to the braking pulses will be set out below, in particular concerning the braking frequencies FBra and the corresponding correction frequencies Fcor which are advantageously envisaged in a preferred variant of the first correction mode of a delay, and also in a preferred variant of a first mode of correction of an advance (which will be implemented in an embodiment described below), in which provision is made to correct an advance detected in the time displayed by a series of braking pulses at a frequency FINF, already defined previously, resulting in a correction frequency FlCor, also defined previously, which is lower than the reference frequency F0c.

Figure 5 shows a first part of a correction period with a relatively high ratio between the correction frequency FSCor = 3.5 Hz and the setpoint frequency F0c = 3.0 Hz (substantially equal to the natural frequency of the resonator when it oscillates freely, represented by oscillation 82), namely a ratio RS = FSCor / F0c = 3.5 / 3.0 = 1.167. When applying to the mechanical resonator braking pulses 84 with a braking frequency FBra = FSUP = 2 FSCor = 7.0 Hz (case N = 1) and a sufficient braking force torque, allowing in the transient phase PHTrde sufficiently reduce the amplitude of the oscillation 86 of the oscillating resonator to finally stop it during each braking pulse, one can impose on this resonator relatively quickly the corresponding correction frequency, that is FSCor = 3.5 Hz. that already after one second the desired synchronization is obtained in the example given, but a phase PHSt of stabilization of the oscillation occurs at the start of the synchronous phase PHSyn. In the case shown, the amplitude increases again during the stabilization phase to finally stabilize at an amplitude corresponding to approximately one third of the initial amplitude of the free resonator.

A demonstrator (a prototype of the timepiece according to the invention) was produced for the case presented in Figure 5. By applying periodic braking pulses at the frequency FSUP = 7.0 Hz to the mechanical resonator , we obtained a lead of 7 hours on the display of the timepiece for a correction period of 6 hours, and this very precisely. We have thus 'won' precisely 1 hour in 6 hours of real time. Such a result opens perspectives for corrections of the time indicated by the display which are other than corrections of a time drift of this display due to the only imprecision of the resonator operating freely (that is to say in no braking pulses). Thus, as will be seen in another embodiment described below, the present invention makes it possible to correct the jump of 1 hour which occurs at a seasonal change of the hour (in particular for the passage of the hour of winter to summer time when the legal time is advanced). We can even think about correcting a change of time zone that may occur during a trip.

Figure 6 shows the free oscillation 82A of a mechanical resonator, a first oscillation 86A of this resonator in a phase synchronous with a correction period where the ratio RS between the correction frequency FScor and the setpoint frequency F0c is relatively low (i.e. relatively close to '1'), and a second oscillation 86B of this resonator in a phase synchronous with a correction period where the ratio RS between the correction frequency FSCor and the frequency of setpoint F0c is relatively high (that is to say relatively far from '1'). The first oscillation 86A results from a series of periodic braking pulses 84A of relatively low intensity and occurring once per oscillation period (which corresponds to the case N = 2 with FSUP = FSCor). On the other hand, the second oscillation 86B results from a series of periodic braking pulses 84B of relatively high intensity and occurring once per alternation of the oscillation (which corresponds to the case N = 1, i.e. FSUP = 2 · FSCor) .

By appropriately selecting the braking torque and the braking frequency, it is observed that the correction frequency can vary continuously between the setpoint frequency F0c and a certain higher frequency FSCmax, for the correction of a delay in the time displayed, and continuously between the reference frequency F0c and a certain lower frequency FICmax, for the correction of an advance in the displayed time. The upper frequency FSCmax and the lower frequency FICmax are not values that can easily be calculated theoretically. It is necessary for each timepiece to determine them practically. Note that although this information is interesting, it is not necessary. What is important is that the braking frequencies are selected and the braking torques available are suitable to generate during each correction period, preferably fairly quickly, a synchronous phase during which the mechanical resonator can oscillate at the correction frequency provided by the mathematical relation given previously, without being stopped in its oscillation (i.e. it is necessary to avoid stopping the resonator so that it cannot start again from the position shutdown, which would lead to a shutdown of the display drive mechanism).

In Figure 6 is indicated a safety angle θSec below which, in absolute value, one will avoid stopping the mechanical resonator (that is to say between -θSecet θSec), and therefore above which the amplitude, in absolute value, must practically remain during the synchronous phase, at least after the stabilization phase. Advantageously for the operation of the mechanical resonator, the angle θSec is expected to be equal to or, preferably, greater than an angle θZI (see Figure 10) which corresponds to the coupling angle between the resonator and the exhaust associated with it. , on one side and on the other side of the neutral position of the resonator defined by the angular position of the coupling pin carried by the balance plate when this resonator is at or passing through its rest position. In order to stop the mechanical resonator during a braking pulse, the angular coupling zone (-θZI to θZI) between the mechanical resonator and the escapement is thus declared 'prohibited zone' (it will be noted that it is possible to brake in this prohibited zone during the transitional phase, but avoid stopping the resonator in this prohibited zone). It will be noted that, in the useful operating range of the resonator, it may be necessary, in order to maintain correct operation of the escapement and in particular to ensure the release phase, that the safety angle θSec be greater than the coupling angle. θZI. The person skilled in the art will know how to determine a value for the safety angle θSec, for each mechanical movement associated with a correction device according to the first embodiment. The coupling angle θZI can vary from one mechanical movement to another, in particular between 22 ° and 28 °.

The condition of not blocking the resonator in the angular safety zone during the delay correction period is important because a count of the flow of time via the escapement (that is to say the timing time display drive mechanism) must continue during this delay correction period. Thus, very advantageously, said frequency FSUP and the duration of the periodic braking pulses are selected so that, during said synchronous phase of a correction period in the context of the first mode for correcting a delay, the periodic braking pulses each intervene outside a coupling zone between the oscillating mechanical resonator and the escapement, preferably outside a defined safety zone for the mechanical movement. The same applies to the selection of said frequency FINF and the duration of the periodic braking pulses within the framework of the first mode of correction of an advance.

To guide the person skilled in the art in the choice of the correction frequencies and the corresponding braking frequencies, a mathematical model has been established on the basis of the equation of motion of a mechanical oscillator. To determine a maximum correction, positive or negative, we consider the resonator in a synchronous and stable phase. Then, a simplification is introduced for the sustaining force applied to the resonator by the energy source via the exhaust, considering it of the cos (out) type. It will be noted that this simplification is prudent in that it decreases the maximum value relative to the real case where the whole of the energy supplied to the resonator occurs in the forbidden zone θZIdefined previously. Finally, we consider the duration of the braking pulses very small, in fact punctual, by defining the braking frequency FBracas the inverse of the time value Tsec at which the resonator reaches, in the equation of motion given below, l 'safety angle θSec in the half-wave corresponding to the number N selected in the relation FCor = N · FBra / 2.

To find the maximum correction and therefore the minimum or maximum period depending on whether the time error to be corrected is negative (delay) or positive (advance), the time t = 0 is given by a braking pulse during which the oscillator is stopped at the safety angle θSec. Then, in the stable synchronous phase, the resonator must stop at the next braking pulse at the earliest, respectively at the latest also at the safety angle (-1 <N>) θSec within a time range given by the value of N and by the fact that the correction frequency is expected to be greater or less than the reference frequency F0c to correct the delay or advance.

In this case, the equation of motion is given by: where τ = Q · T0 / π, T0 is the period of free oscillation (considered equal to T0c = 1 / F0c for the calculations) and θ0 is the amplitude of free oscillation.

It is therefore observed that the quality factor Q of the mechanical resonator is involved in the equation of motion.

To obtain a correction frequency FSCors greater than the reference frequency F0c, Tsec must intervene in a half-wave after the resonator has passed through its neutral / rest position. We therefore have for a given N:

The maximum braking frequency FSBmax (N) = 1 / TSecet the maximum correction frequency FSCmax (N) = N-FSBmax / 2.

To obtain a correction frequency Flcor lower than the reference frequency F0c, TSec must intervene in a half-wave before the resonator passes through its neutral / rest position. We therefore have for a given N:

The minimum braking frequency FIBmin (N) = 1 / TSecet the minimum correction frequency FICmin = N · FIBmin / 2.

Figures 7A and 7B respectively represent the curves of RSmax (N = 1) = FSCmax (N = 1) / F0c and of RSmax (N = 2) = FSCmax (N = 2) / F0c as a function of the amplitude θ0de the free oscillation of the mechanical resonator for various quality factors Q of this mechanical resonator. It is observed that the smaller the quality factor, the greater the ratio RSmax (N).

Figure 8 gives, for a resonator having a quality factor Q = 100, a free amplitude θ0 = 300 ° and a safety angle θSec = 25 °, the higher correction frequency ranges, for a setpoint frequency F0c and various respective values of N, which can be envisaged in the context of the first mode of correcting a delay, by representing the ratio RS = FSCor / F0c which extends between the value '1' and RSmax (N).

Figure 9 gives, for a resonator having a quality factor Q = 100, a free amplitude θn = 300 ° and a safety angle θSec = 25 °, the lower correction frequency ranges, for a setpoint frequency F0c and various respective values of N, which can be envisaged within the framework of the first mode of correction of an advance, by representing the ratio RI = FICor / F0c which extends between Rlmax (N) and the value '1'.

As indicated above, the ranges given in Figures 8 and 9 result from a simplified theoretical model. It can be seen that the maximum and respectively minimum correction frequencies depend on several parameters. These figures give a good indication of the reality for a mechanical movement having fairly standard properties. However, for each given mechanical movement, it will be necessary to define the limit values if one wishes to approach them in order to make large corrections in relatively short correction periods.

After having explained in detail the arrangement of the electronic control unit and the operation of the correction device of the first embodiment of the timepiece according to the invention to correct a delay in the time displayed by the timepiece, the arrangement of the electronic control unit according to this first embodiment for correcting an advance in the displayed time according to a second mode of correcting an advance will be explained below.

To allow the implementation of the second method of correcting an advance, the timepiece comprises a device for blocking the mechanical resonator. In general, in the context of the second mode of correcting an advance, the electronic control unit is arranged to be able to supply the blocking device, when the external correction signal received by the receiving unit corresponds to an advance in the displayed time that it is planned to correct, a control signal which activates the blocking device so that this blocking device blocks the oscillation of the mechanical resonator during a correction period determined by the advance to be corrected, so as to stop the operation of said drive mechanism during this correction period.

In the first embodiment described with reference to Figures 1 and 2, the timepiece 2 comprises a locking device which is constituted by the braking device 22, in particular by the piezoelectric actuator 22A, which serves also to the implementation of the first mode of correction of a delay. When the external correction signal SExt, received by the reception unit 30, corresponds to an advance in the displayed time that it is intended to correct, the logic circuit 60 of the electronic control unit 28A (Figure 2) supplies a control signal SA to the time counter 70 (timer) which is programmable. This timer 70 then generates a signal SC2 for activating the braking device 22, via the 'OR' ('OR') gate 66 or another switch, for a correction period PAcor the duration of which is substantially equal to the corresponding advance. TErrà correct. The periodic activation signal SC2 then forms the control signal SCmd. It will be noted that the activation signal SC2 controls the braking device 22 in a mode of blocking the mechanical resonator for a relatively long period, namely during substantially the entire correction period PACor = TErr. To this end, the voltage then supplied by the supply circuit 26 between the two electrodes of the piezoelectric blade 24 may differ from that provided to generate the periodic braking pulses to correct a delay. This voltage is selected so that the braking force applied to the mechanical resonator can stop it, preferably quite quickly, and then block it until the end of the correction period.

In a variant, the electric voltage applied to the piezoelectric blade 24 is provided to vary during the correction period. For example, it is possible to provide a higher voltage at the start of the correction period, which is selected to quickly stop the resonator, in particular during the alternation of the oscillation of this resonator in which the start of the period occurs. correction, and then decrease the voltage to a lower value but sufficient to keep the resonator stationary. Advantageously, the electric voltage will be selected so that the resulting braking force cannot stop the mechanical resonator in the forbidden angular zone (-θZL to θZI) defined above. For this purpose, the braking torque is selected large enough to be able to stop the resonator and lock it in the angular stop position, whatever it may be, and small enough so that this braking torque cannot stop the resonator in the forbidden angular zone. Preferably, one will avoid stopping the resonator in the angular safety zone (-θSecà θSec), described previously. This last condition is important when the resonator is not self-starting. In general, it suffices to ensure that the resonator can start again at the end of the correction period.

According to a specific variant making it possible to ensure a rapid stopping of the resonator outside the aforementioned angular safety zone, a preliminary phase occurring before the correction period where the resonator is blocked (that is to say where it remains stopped following its stop intervening quickly or immediately at the start of the correction period). During the preliminary phase, provision is made to use the first mode of correction of a delay available in the first embodiment. It can be seen that in the synchronous phase of the first correction mode described above, the passage through an extreme angular position occurs during each braking pulse. Thus, the braking pulses are in phase with passages of the mechanical resonator through one of its two extreme angular positions, each of these passages defining the start of an alternation. Advantage is taken of this fact by activating the frequency generator 62 during the preliminary phase, which is intended to be of relatively short duration but nevertheless of sufficient duration for the establishment of a synchronous phase where the resonator is synchronized on the frequency FScor. The preliminary phase ends, for example, with a last braking pulse which is immediately followed by the correction period with activation of the braking device in the blocking mode. Thus, it is known that the resonator is blocked outside the angular safety zone. The braking torque for the preliminary phase can be expected to be different from that used for the correction of a delay explained above.

As the behavior of the frequency during the transient phase at the start of a series of periodic braking pulses may vary from case to case, it is hardly possible to determine the error generated by the preliminary phase. . However, it is possible to estimate a maximum error. For example, if the FSUP frequency = 1.05-F0c (correction of 30 seconds in 10 minutes) and the preliminary phase is scheduled with a duration of 10 seconds (selected duration greater than those of transient phases that may occur), we can estimate the maximum error at 0.5 seconds (half a second). For a mechanical movement, if such an error is not negligible, it is relatively small since a conventional mechanical movement has a daily error generally between 0 and 5 to 10 seconds.

Referring to Figure 10, we will describe a second embodiment of a timepiece according to the invention which differs from the first embodiment by the arrangement of the locking device to advantageously implement the second mode of correcting an advance in the time display associated with the mechanical movement of the timepiece. This mechanical movement 92 comprises a classic escapement 94 formed by an anchor wheel 95 and an anchor 96 which can oscillate between two pins 95. The anchor comprises a fork 97 between the horns of which the ankle is conventionally inserted at each alternation. 98 also forming the escapement and carried by a plate 100 which is integral with the shaft 102 of the balance 104 (shown partially) of the mechanical resonator or integrally formed with this shaft (that is to say that the shaft is machined with a longitudinal profile defining the plate). The plate 100 is circular and centered on the central axis of the shaft 102 which defines the axis of rotation of the balance 104.

The timepiece comprises a locking device 106 which is distinct from the braking device 22A (Figure 1) used for the correction of a delay. This locking device is therefore dedicated to the implementation of the second method of correcting an advance. The locking device is formed by an electromechanical actuator, in particular by a piezoelectric actuator of the same type described in connection with Figure 1. According to the variant shown, the actuator comprises a flexible piezoelectric blade 24A and its two electrodes are supplied with voltage. by a 26A power supply circuit. The blade 24A has at its free end a projecting part 107, forming a stud, which is located on the side of the plate 100. The blade extends in a direction parallel to a tangent of the circumference of the plate, at a small distance from this circumference. circular. The plate has a through-hollow 108, which opens radially on the periphery of the plate and whose profile in the general plane of the plate is provided to allow the stud 107 to be housed there when it is located angularly in front of the plate. this hollow and that the piezoelectric actuator 106 is activated. According to the variant shown, the hollow 108 is diametrically opposed to the pin 98 and the stud is located angularly at the zero position of the pin (that is to say at the angular position of this pin when the resonator is at rest, respectively passes through its neutral position). Note that this zero angular position of the ankle normally defines the zero angular position of the balance 104, and therefore of the mechanical resonator, in a fixed angular reference relative to the mechanical movement 92 and centered on the axis of rotation of the balance.

In an equivalent variant, the hollow can be arranged at another angle relative to the ankle, for example at 90 °, and the actuator 106 is then positioned on the periphery of the plate so that the stud 107 is diametrically opposed to the hollow when the resonator is at rest. Thus, whatever the alternation and the angular position during the activation of the piezoelectric actuator, the pad will enter the hollow when the resonator is in an angular position equal, in absolute value, substantially at 180 ° (this being exactly the case if the balance is set to the mark, that is to say that the pin is aligned with the respective centers of rotation of the balance and of the anchor when the resonator is at rest). This value of 180 ° is clearly outside the safety zone (it is greater than the safety angle defined previously) and it is generally lower than the range of amplitudes of the mechanical resonator corresponding to its useful operating range.

Then, according to the advantageous variant shown in Figure 10, the side walls of the hollow 108 are parallel to the radius passing through its center and the axis of rotation of the balance. In an equivalent variant, these side walls are provided radial. Likewise, the stud 107 has two side walls, perpendicular to the general plane of the plate, which are parallel to the radius passing through its center and the axis of rotation of the balance or which are, in the equivalent variant, substantially radial relative to the rotation axis. Thanks to this arrangement, when the stud 107 is introduced into the hollow 108 which then serves as its housing, this stud blocks the rotation of the plate 100 and therefore of the balance 104 by a substantially tangential force, the direction of which is substantially parallel to the longitudinal direction. general of the piezoelectric blade 24A. When the actuator 106 is activated, the end of the blade carrying the stud 107 undergoes a substantially radial displacement, relative to the axis of rotation of the balance, and the stud can then, depending on the angular position of the balance at this moment, either exert an essentially radial force on the circular lateral surface of the plate 100, or at least partially enter the hollow 108. The actuator must only be arranged so that the stud can undergo, when this actuator is activated, a sufficient displacement to be introduced into the hollow when the latter is located in an angular position corresponding substantially to that of the stud (in a fixed angular reference relative to the stud).

A relatively low friction force can be provided when the stud comes to rest against the circular lateral surface of the plate at the start of a correction period, that is to say following the activation of the actuator, in the case where the hollow is not opposite the stud when its proximal surface reaches the level of the circular circumference of the plate. Thus, it can be ensured that the amplitude of the resonator decreases little during the initial braking operated by the pad exerting a radial force against this circular lateral surface. Then, when the pad is inserted into the hollow while the latter is in front of the pad, the radial force exerted by the piezoelectric blade on the plate can be very low, or even zero. The electrical energy required to block the resonator during the correction period can therefore be relatively small, much smaller than in the case of the first embodiment.

When the correction device of the timepiece receives an external correction signal corresponding to the correction of an advance detected in the time display, its control logic circuit, similarly to the operation of the first embodiment, activates the blocking device 106, by supplying it with a control signal SC2 similar to that described previously in the context of the first embodiment, for a period substantially equal to the time error to be corrected. Thanks to the arrangement of a hollow in a circular plate centered on the axis of rotation of the resonator and of an actuator having a corresponding part, but preferably less wide than the hollow, which is arranged to be able to undergo a movement substantially radial between a non-interaction position, corresponding to a non-powered state of the actuator, and a state of interaction with the balance of the resonator, corresponding to a powered state of the actuator in the variant described here, the start of the The activation of the blocking device 106 can take place at any time, whatever the angular position of the resonator and whatever the direction of the oscillation movement (therefore independently of the current alternation among the two alternations forming each period d 'oscillation). This is very advantageous.

Finally in connection with the second embodiment, the electromechanical actuator may be of another type than that shown in Figure 10. For example, in a variant, the actuator may comprise a ferromagnetic or magnetic core which can be moved under the action of a magnetic field generated by a coil. In particular, this core is collinear with the coil and it comprises an end part coming out of the coil at least when the actuator is activated, this end part forming a finger which is configured to be able to come to be introduced into the coil. hollow of the plate, this finger having in particular an end part with the shape of the pad 107. In a preferred variant, the actuator is a bistable actuator. The power supply to the actuator is advantageously maintained, during its activation to pass from the non-interaction position to the interaction position, until the pad is at least partially entering the hollow 108. Such a This variant is particularly interesting because the actuator must not exert any blocking force by applying radial pressure on an element of the resonator balance in its two stable positions corresponding respectively to the non-interaction position and the expected interaction position. In this preferred variant, the energy consumption can be very low, regardless of the duration of the correction period, which is very advantageous.

With reference to Figure 11, a third embodiment of a timepiece according to the invention will be described, which differs essentially from the first embodiment by the arrangement of the locking device making it possible to advantageously implement the second mode of correcting an advance in the time display associated with the mechanical movement of the timepiece. The references already described in relation to Figures 1 and 2 will not be described here again in detail. As in the second embodiment, the timepiece 112 according to the third embodiment comprises a locking device 114 which is distinct from the braking device 22B used for the correction of a delay. The braking device 22B is similar to the braking device 22A already described and its operation is similar, that is to say it is suitable for the implementation of the first mode of correcting a delay explained in detail previously. This braking device 22B comprises an electric power supply 26B which is partially common to that of the locking device 114 and which receives the control signal Sci. Then, it comprises a piezoelectric blade 24B in the form of a square, this shape being provided here as a possible variant and to make it easier to arrange the piezoelectric blade 24B and the piezoelectric blade 25, forming the locking device, on a same surface of a support containing the common feed 26B. However, other variants can be provided, in particular a braking device identical to that of FIG. 1 with a supply circuit entirely separate from that of the locking device.

The locking device 114 is remarkable for at least two reasons. First, it acts on a conventional mechanical resonator 14 requiring no modification, in particular no specific machining unlike the second embodiment. Then, the locking device is a bistable device, that is to say a locking element has two stable positions, namely here the rocker 115. The locking device is arranged so that a first of the two stable positions of the rocker corresponds to a position of non-interaction with the rocker 16 while the second of these two stable positions corresponds to a blocking position of the resonator via a radial force exerted by a blade 116, forming the rocker 115, on the serge 20 of the balance. The blade 116 is pivoted around an axis arranged in the mechanical movement 4A (in another variant, the rocker is arranged so that its pivot axis is arranged on a support separate from the mechanical movement and located in a correction module) . In a variant, this axis is formed by a fixed pin around which an annular end part of the blade 116 is mounted. This blade is rigid or semi-rigid, a slight flexibility being able to be advantageous.

The blade 116 is associated with a particular magnetic system making it possible to generate the bistable nature of the latch 115 and consequently of the locking device 114. The magnetic system comprises a first magnet 118, carried by the blade and therefore integral in rotation of this blade, a second magnet 119 fixedly arranged in the mechanical movement, or relatively to the latter, and a ferromagnetic plate 120 arranged between the first magnet and the second magnet, at a short fixed distance from the second magnet 119 or against it (for example the plate is glued against this magnet, only a layer of glue then separating the magnet from the plate).

The first and second magnets 118, 119 have magnetic polarities which are opposite and their respective magnetic axes are substantially aligned. Thus, in the absence of the ferromagnetic plate, these two magnets would constantly exert a repulsive force on each other and the rocker would remain or always return, in the absence of forces external to the magnetic system, in a position where the blade is in abutment against a pin 124 for limiting its rotation. However, thanks to the arrangement of the ferromagnetic plate, there is a reversal of the magnetic force which is exerted between the two magnets. More precisely, when approaching the mobile magnet 118 from its remote position (shown in Figure 11), the repulsive force decreases until it is canceled out and finally reversed when the mobile magnet comes close to it. the ferromagnetic plate. Thus, when the mobile magnet 118 is located very close to or against the ferromagnetic plate 120, this mobile magnet is subjected to a magnetic force of attraction. This astonishing physical phenomenon is set out in detail in patent application CH 711 889, which also contains some horological applications.

The latch 114 is arranged so as to have two stable positions in the absence of forces external to the magnetic system of the locking device. The first stable position is a non-interaction position in which the blade 116 is in abutment against the pin 124, the mobile magnet 118 then undergoing a magnetic repulsion force which maintains the rocker against this pin. The second stable position is an interaction position in which the blade 116 is in abutment against the rim 20 of the balance 16, the mobile magnet 118 then undergoing a magnetic force of attraction which maintains the lever against this rim. The ferromagnetic plate 120 is arranged so that the blade exerts a radial force for blocking the balance 16, and therefore the resonator 14, when the lever is in its second stable position. In order for the blade to be able to exert a locking force against the outer lateral surface of the rim 20, the surface of the plate 120 located in front of the mobile magnet 118 must be slightly recessed relative to the proximal surface of this magnet. movable when the blade 116 comes into contact with the rim. If the blade is semi-rigid and therefore exhibits some flexibility, it is possible that the moving magnet finally abuts against the proximal surface of the ferromagnetic wafer, but then the blade is flexed.

To move the bistable latch 115 between its two stable positions, in both directions, the locking device comprises a device for actuating this latch. This actuating device 126 is controlled by the logic circuit of the electronic control unit via its supply circuit which receives the control signal SC2. What is remarkable is the fact that the blocking force exerted by the blocking device does not come from an electrical supply of this blocking device but from the magnetic system which forms it. Thus, the blocking device requires electric power only at the start and at the end of the blocking period occurring in the second mode of correction of an advance, during the switching of the flip-flop between its two stable states.

By way of example only, the actuating device 126 is formed by a piezoelectric device comprising a piezoelectric blade 25 which can be bent in both directions from its rest position (not activated position), by the application of an electric voltage, supplied by the supply circuit 26B, between its two electrodes respectively with a positive and negative electric polarity. The rocker 115 comprises a fork 122 defining a cavity inside which is housed the free end of the piezoelectric blade 25. The width of the cavity is preferably provided greater than the width of the free end of the blade 25. and this blade is arranged so that it is against a first side wall of the cavity when the bistable rocker is in its first stable position and against the second side wall of this cavity when the bistable rocker is in its second stable position. By adjusting the width of the cavity, it is possible to have the piezoelectric blade 25 substantially straight, that is to say without bending, in the two stable positions of the rocker. However, a slight residual bending as shown, in the absence of voltage applied by the power supply, can be provided and be advantageous given the path to be taken by the end of the piezoelectric blade.

In an advantageous variant, the actuating device of the rocker is formed by a magnet-coil electromagnetic system, the magnet being in particular fixed to the rocker and the coil is fixed to the support of the rocker in a manner substantially aligned with the magnet. Depending on the polarity of the electric voltage applied to the coil, the latch is subjected to a force of magnetic attraction or repulsion, thus making it possible to easily pass the latch from one of its two stable positions to the other in both directions.

In another variant leading to the same physical phenomenon and therefore to the same desired effect, the ferromagnetic plate 120 is arranged against the mobile magnet 118, to which it is integral. Finally, in another variant, provision is made to combine the second and third embodiments. To do this, the blade of the lever comprises, in the region of contact with the rim 20, a stud which projects in the direction of this rim, which has a hollow along its generally circular circumference. The person skilled in the art will know how to arrange the locking device so that its first stable position is a non-interaction position and its second stable position is an interaction position in which the stud is at least partially inserted into the hollow, this stud exerting generally initially a dynamic dry friction against the outer lateral surface of the rim, when the rocker is actuated by the actuator to move from its first stable position to its second stable position at the start of a period of correction of a advance, before entering the hollow when the latter is in front of the stud during the oscillation of the balance.

With reference to Figures 1 and 12, a fourth embodiment of a timepiece will be described below. This fourth embodiment is a preferred embodiment which differs from the first embodiment substantially by the method of correcting an advance and by some improvements and by variants relating to certain units of the correction device 132.

First, the receiving unit 30B of the correction device is a BLE unit (acronym for the abbreviation of 'Bluetooth Low Energy'). Then, the power supply 130 of the correction device is more advanced than in the variant shown for the first embodiment (Figure 2). The energy recuperator is a solar cell 54A, in particular arranged at the level of the dial or of the bezel bearing the glass protecting the dial. This dial generally forms part of the time display. In addition, a photodiode 136 is provided to receive a light signal for activating the correction device supplied by the external electronic device, in particular from the mobile telephone 40, in order to trigger / start in the timepiece a correction cycle of the time displayed on the basis of an external correction signal SExt then supplied by the external electronic device (in other words to launch the process for correcting the displayed time which is implemented in the correction device 132).

The power supply 130 comprises a circuit 134 for managing the power supply of the correction device 132. This circuit is able to receive various information from the electricity accumulator 56 and it receives from the photodiode 136 a signal of wake-up SW-UP when this photodiode receives a specific light signal from the mobile telephone 40. Various measures known to the person skilled in the art can be taken to prevent the photodiode from sending unwanted wake-up signals to the correction device. In particular, a narrow specific frequency band can be selected. In addition, the light signal can be coded, in particular by a modulation of its light intensity and the photodiode 136 or the management circuit 134 is then arranged to be able to determine whether the logic code corresponding to this modulation does indeed relate to a planned wake-up signal. Once the management circuit 134 has received a valid wake-up signal, it detects the level of energy available in the accumulator 56. As in the first embodiment, if the level of energy is insufficient to lead to its recovery. After the correction process, the management circuit can react in various ways. In particular, it can wake up the BLE unit and send a message to the mobile phone via this BLE unit so that this external device gives this information to the user via its electronic display. Then, he can either remain on standby ('Standby') for a supply of electrical energy via his solar cell or another means of energy recovery provided in addition, or start as far as possible an all-round correction cycle. knowing that he may not be able to finish it correctly due to lack of energy available.

When the level of energy available is sufficient for a correction cycle, the management circuit 134 activates, in a first variant, firstly the BLE unit while waiting for an external correction signal SExt. The BLE unit usually has the resources to check whether an external signal received at the correct frequency has the standard format, but the 60A control logic circuit may need to be activated for analysis of a signal received by the unit. BLE unit if this signal is received at the correct frequency and has the correct format. In the latter case, it is the analysis of the digital correction signal Scor which will indicate, if necessary, that the received signal is not appropriate or incomplete. Thus, in a second variant, the management circuit directly activates the BLE unit and the control logic circuit, but preferably not the other elements of the correction device. If no correction signal is received or received correctly, the management circuit 134 can, in a variant, inform the mobile telephone (directly or via the control logic circuit 60A, the latter then having to be activated to do this) , and either wait for a new external correction signal within an additional time, or return to a 'Standby' mode while waiting for a new wake-up signal. In another variant where the timepiece comprises electronic or electromechanical means for giving a visible signal to the user, the management circuit 134 can then use this means to itself indicate to the user that it does not. is not able to perform a correction, because it does not or does not receive the external correction signal correctly.

In the first variant mentioned above, when the BLE unit receives an external correction signal SExt at the right frequency and in the right format, it activates at least the control logic circuit 60A to which it supplies the digital correction signal for analysis and following a correction cycle. If the digital signal Scor includes the expected time information, in particular the time error TErr to be corrected and its mathematical sign '+/-' indicating whether it is a delay or an advance to be corrected (the latter information being binary, only one bit can be provided for this purpose), the management circuit 134 then activates the entire correction device and the supply circuit 26C of the braking device.

As the fourth embodiment is characterized by an implementation of the first mode of correcting a delay, as in the first embodiment, and of the first mode of correcting an advance already described previously but not implemented in the As a first embodiment, any planned correction is made by a series of periodic braking pulses during a correction period. In a main variant, all the braking pulses are provided with the same duration Tp. Thus, one and the same timer 64 is necessary to determine the duration of the braking pulses and this timer is arranged, in the variant shown in FIG. 12, in the supply circuit 26C. This timer provides an activation / actuation signal SActà a switch 138 placed between a voltage source 140 and the braking member 24C acting on the balance. The braking member 24C is for example similar to the piezoelectric blade (Figure 1) of the variant shown for the first embodiment. Thus, the switch 138 controls the power supply to the actuator forming the braking device. The timer 64 receives a first control signal S1Cmd from a switching device 66A which is controlled by the logic circuit 60A so that the first control signal is selectively formed by a periodic digital signal among three periodic digital signals provided SFS, SFI and SF0c which respectively have three different frequencies FSUP, FINF and F0c. The periodic digital signal periodically resets the timer at the selected frequency and, in response, this timer periodically activates the actuator for a duration Tp, making switch 138 temporarily conductive, to generate a series of periodic braking pulses at this time. selected frequency.

When the digital correction signal indicates that a time error corresponds to a delay to be corrected or that the control logic circuit has itself determined such a time error to be corrected on the basis of the information contained in the external signal of correction, the logic circuit 60A determines, as a function of the selected frequency FSUP, a corresponding correction period PRCor a number of periodic braking pulses to be generated at the frequency FSUP during the current correction cycle. To do this, he uses the formula relating to this calculation which was established previously. To apply the series of braking pulses at the frequency FSUP leading to a correction frequency FSCor greater than the setpoint frequency, it uses the frequency generator 62, already described, which supplies a periodic digital signal SFS at the frequency FSUP to the timer 64 via the switch 66A, which is controlled for this purpose by the control logic circuit.

When the digital correction signal indicates that a time error corresponds to an advance to be corrected or that the control logic circuit has itself determined such a time error to be corrected on the basis of the information contained in the external signal of correction, the logic circuit 60A determines, as a function of the selected frequency FINF, a corresponding correction period PACor or a number of periodic braking pulses to be generated at a frequency FINF, defined previously, during the current correction cycle. To do this, he uses the formula relating to this calculation which was established previously. To apply the series of braking pulses at the frequency FINF leading to a correction frequency FlCor lower than the reference frequency, it uses the frequency generator 142 which supplies a periodic digital signal SFI at the frequency FINF to the timer 64 via the switch 66A, which is controlled for this purpose by the logic control circuit.

In general, to allow the implementation of the first mode of correction of an advance, the electronic control unit 28B is arranged to be able to provide the braking device, when the external correction signal received by the unit reception corresponds to an advance in the displayed time that it is intended to correct, a control signal derived from a periodic digital signal supplied by a frequency generator at a FINF frequency, during a correction period, to activate the braking device so that it generates a series of periodic braking pulses applied to the mechanical resonator at the frequency FINF. This FINF frequency is provided and the braking device is arranged so that the series of periodic braking pulses at the frequency can generate, during the correction period, a synchronous phase in which the oscillation of the mechanical resonator is synchronized with a correction frequency Flcor which is lower than the reference frequency FOc provided for the mechanical resonator. The (duration of the) correction period and therefore the number of periodic braking pulses in said series of periodic braking pulses is determined by the feed to be corrected.

[0100] The correction device of the fourth embodiment comprises an improvement to increase the precision of the correction carried out and also to allow the application of relatively high braking torques, in particular for corrections at frequencies relatively far from the reference frequency. , without running the risk of permanently stopping the mechanical resonator by stopping, during a braking pulse at the start of the correction period, in the angular coupling zone between the resonator and the escapement or more generally in the angular zone of security described previously. According to this improvement, the timepiece comprises a device for determining the passage of the oscillating mechanical resonator through at least one specific position, this device for determining a specific position of the mechanical resonator allowing the electronic control unit to determine a specific instant at which the oscillating mechanical resonator is in said specific position, and therefore to determine the phase of the resonator. Then, the electronic control unit is arranged so that a first activation of the braking device occurring at the start of the correction period, to generate a first interaction between this braking device and the mechanical resonator, is triggered as a function of said specific moment.

According to an advantageous variant of the improvement described above and with reference to Figure 12, the correction device further comprises a frequency generator 144 which is arranged so as to be able to generate a periodic digital signal SF0c at the setpoint frequency F0c provided for the resonator. The electronic control unit 28B is arranged to be able to supply the braking device with a control signal derived from the periodic digital signal SF0c, during a preliminary period directly preceding the correction period, to activate the braking device so that this control device braking generates a preliminary series of periodic braking pulses which are applied to the mechanical resonator at the reference frequency FOc. To do this, the control logic circuit 60A supplies the generator 144 with a control signal SPP. The duration Tp of the periodic braking pulses and the braking force applied to the oscillating resonator, during the preliminary series of periodic braking pulses, are provided so that none of these braking pulses can stop the oscillating resonator in the coupling zone of this oscillating resonator with the escapement which is associated with it (between -θZI and θZI) or, preferably, in a predefined safety zone (between -θSecet θSec) including the coupling zone (these zones have been explained previously ).

Then, the duration of the preliminary period and the braking force applied to the oscillating resonator, during the preliminary series of periodic braking pulses, are provided so as to generate at least at the end of the preliminary period a synchronous phase preliminary in which the oscillation of the mechanical resonator is synchronized (on average) on the reference frequency F0c. In the variant shown, the electric voltage source 140 is variable and controlled by the logic circuit 60A which supplies it with a control signal S2Cmd, so that the voltage level applied to the braking member 24C can be varied to vary the braking force. It is thus possible to provide a lower braking force during the preliminary period than during a correction period which follows it. The braking force can also be varied during the preliminary period and / or the correction period.

The correction period, provided for correcting an advance or a delay, directly follows the preliminary period. More precisely, the triggering of a first braking pulse at the frequency or FSUP, at the start of a period for correcting the displayed time, occurs after a determined time interval relative to an instant at which the last pulse of braking of the preliminary period, so that this first braking pulse occurs outside a predefined safety zone including the aforementioned coupling zone. This condition is easily fulfilled by the fact that the resonator is in a synchronous phase at least at the end of the preliminary period; which has the consequence that the resonator stops during the last braking pulse of this preliminary period. Thus, a reversal of the direction of rotation occurs during said last braking pulse, so that the start of a new alternation of the oscillation of the resonator occurs during this last braking pulse. The correction device can thus know, with an accuracy of Tp / 2 (for example an accuracy of 3 ms), the phase of the oscillation. Therefore, the electronic control unit can be arranged so that the control logic circuit can determine an initial time to trigger the first braking pulse which fulfills the aforementioned condition, by activating the frequency generator 62 or 142, depending on the requirement. correction required, after a determined time interval since said last braking pulse which ensures that the first braking pulse is outside the predefined safety zone.

In addition, the instant of triggering of said first braking pulse and the braking force applied to the oscillating resonator, during this first pulse and then during the periodic braking pulses which follow during the correction period, are provided so that the phase synchronous with the correction frequency Flcor or FScor preferably starts from the first braking pulse, or from a second braking pulse if the first braking pulse is used to reduce the amplitude of the oscillation without succeed in stopping the resonator, and that this synchronous phase remains throughout the correction period. In a particular variant, the first braking pulse of the correction period occurs after a time interval corresponding to the inverse of the frequency FSUP or FINF, depending on the correction required, following the instant at which the last braking pulse of the preliminary period. In another particular variant, said time interval is selected equal to the inverse of double the correction frequency FSCor or FICor, depending on the correction required, or to the inverse of this frequency FScor or Flcor. The improvement described above is remarkable because it uses the resources available, in particular the braking device provided to perform the required correction, to determine the phase of the oscillation of the resonator. No specific sensor for determining this phase is necessary. In addition, no significant time drift is induced by the preliminary period (generally at most TOc / 4). Note that the generators at the various frequencies have been shown separately in Figure 12, but only one programmable frequency generator device can be used.

With reference to Figures 13 to 15, a second embodiment of an assembly 150 according to the invention will be described below, which comprises a timepiece 154 according to a fifth embodiment and an external device 152 according to a second embodiment of an assembly according to the invention. The timepiece is a wristwatch (hereinafter the watch) and the external device forms a box comprising a housing for receiving the watch in a given position. The box 152 is provided with a photographic device 156 arranged in the lid of the box so as to be able to take an image of the entire display of the timepiece when the lid is closed with the timepiece 154 correctly placed in the housing.

[0106] The box 152 is provided with various electronic units and circuits. This box includes: a photographic device comprising a photographic sensor formed by an array of photo-detectors, an image processing algorithm which is arranged to be able to determine the position of at least one determined hand of the display of the timepiece in an image taken by the photographic device (note that this algorithm can be processed in an external server in communication with the box), a time base capable of providing the exact real time, an algorithm for calculating a temporal error between a first temporal datum, indicated by the display at a given instant and detected by the external device via its photographic sensor and its image processing algorithm, and a second temporal datum corresponding to the first temporal datum and supplied substantially to said instant given by the time base, a transmitter of an external correction signal comprising information relating to said temporal error, this transmitter being formed by a BLE unit in the variant shown.

[0107] The box 152 further comprises an electronic display 153, a central control unit and, in order to be able to receive the exact real time regularly or on request, a communication unit (RF unit) which can receive the exact real time by an antenna provided for this purpose (radio synchronization), or a WIFI unit to receive the exact real time via the Internet, or a GPS unit. The box also includes a power supply that can be powered or recharged via a USB or other type socket. Finally, the box includes a wireless charging unit, by magnetic induction, for the watch 154 which includes in particular a Fitness module. This wireless charging unit is preferably arranged in a support inserted into the housing of the box so as to be close to the watch and under the latter when it is placed in the box, in particular to allow recharging of its 56A battery. .

[0108] Watch 154 comprises various electronic elements and circuits. The references already described above will not be described again here in detail. This watch comprises a BLE unit 30B for receiving various signals including in particular a signal for correcting the time displayed by the watch, as well as a braking device 22C, the elements of which have already been described previously, which receives an activation signal SActfrom the electronic control unit which will be described later. Then, the watch 154 comprises a rechargeable battery 56A, preferably by magnetic induction (by contactless means), and a power supply management circuit 134A, similar to that already described in relation to the watch of FIG. 12, As an option, the watch further comprises a Fitness module 156 and an electronic display 158 associated in particular with the Fitness module, which can use the BLE unit to communicate with electronic devices external to the watch, in particular with the box 152, a mobile phone or any other suitable electronic device, for example a computer.

The electronic control unit 28C of the watch 154 is arranged to allow the implementation of the first mode of correction of a delay, according to an improved variant, and to correct an advance according to the first mode of correction or the second method of correction already described. Thus, this electronic control unit comprises a control logic circuit 60B which controls a switching device 66B in parallel with a frequency generator device at the frequencies F0c, FINF and F1SUP and F2SUP. F1SUP and F2SUP are two different values selected for the previously defined FSUP frequency. This frequency generator device is composed of a generator 144 at the frequency FOc, for the implementation of a preliminary period already described in the context of the fourth embodiment of a timepiece according to the invention, of a generator 142 at the frequency also described in the context of the fourth embodiment, and two generators 62A and 62B respectively supplying two periodic digital signals SFS1 and SFS2 having respective frequencies F1SUP and F2SUP. In other words, the frequency generator device is arranged so as to be able to generate, in order to correct a delay in the displayed time, a periodic digital signal selectively at the frequency F1SUP and at the frequency F2SUP to control the braking device. The frequencies F1SUP and F2SUP are provided so that the correction frequency FSCor, to correct a delay according to the first correction mode, can take two different values F1Coret F2Cor, respectively for the two frequencies F1SUP and F2SUP, with the correction frequency F2Cors greater than the frequency F1Cor correction.

[0110] It is advantageously provided that the selection of the frequency F1SUP is carried out when the delay to be corrected, in absolute value, is less than a given value while the selection of the frequency F2SUP is carried out when this delay is equal to or greater than this value. given. The frequency FSUP can therefore take, as a function of the value of the delay to be corrected, at least two different values F1SUP and F2SUP. Depending on the generator activated, the control signal S1Cmdis formed by one of the periodic digital signals SF0c, SFI, SFS1and SFS2. This signal S1cmd itself directly forms the activation signal SAct. It will be noted that no timer is provided to determine the duration of the braking pulses, because it is provided in this variant that it be the periodic digital signals SF0c, SFI, SFS1 and SFS2 which define this duration by their cyclic ratio determined between their state. logic high ('1') and their logic low state ('0'). Thus, for example, the duration of the high logic state determines the duration of each braking pulse, the switch 138 then being closed (transistor on) at the rising edges of the periodic digital signal supplied and being open (transistor not on) at the edges. falling edges of this periodic digital signal.

[0111] In addition, the electronic control unit 28C comprises a timer 70, similar to that described with reference to FIG. 2, to enable the second correction mode already described in the first embodiment to be implemented. a watch according to the invention. This timer 70 supplies a control signal S3Cmd to activate the braking device via an 'OR' ('OR') logic gate 166 also receiving the control signal S1Cmd (it will be noted that the switching operated by the logic gate can be incorporated in the switch 66B, making this logic gate introduced in the diagram of FIG. 15 superfluous to differentiate the first correction mode from the second correction mode). Thus, it is possible to select either the first correction mode or the second correction mode to correct an advance.

It is advantageous to select the first correction mode when the advance to be corrected is less than a given value while the second correction mode is selected when the advance to be corrected is equal to or greater than this given value. As the first mode of correction of an advance makes it possible to consume less electrical energy than the second mode of correction with a braking device of the electromechanical actuator type having a single stable position in the absence of power supply (for example the piezoelectric actuator 22A in Figure 1), the selection between the first and the second correction mode can also depend on the level of the rechargeable battery 56A. Likewise, as the first mode of correcting a delay requires a priori a stronger braking torque in the case of a relatively high ratio between the correction frequency and the reference frequency, the selection between the generator 62A and the generator 62B may also depend on the level of the rechargeable battery.

The fifth embodiment of a timepiece comprises means for being able to correct not only an error in the displayed time, resulting from a time drift of the oscillating resonator or from a manual time setting. imprecise, but also to allow the displayed time to be changed at the appropriate time during a seasonal time change (change from winter time to summer time and vice versa). To do this, the watch 154 comprises an internal clock circuit 162 and a programmable time counter 160. The application installed in an external device (box 152 or a mobile phone 40 of FIG. 1), in order to be able to communicate with the watch. and activate its correction device, includes the function 'seasonal change of time' to program the watch 154 so that it performs, as the case may be, one hour ahead or back one hour (or half an hour, if applicable) on the night scheduled for the time change. To this end, the external device is arranged to be able to send to the watch, via its transmitter intended to communicate with this watch, a correction signal relating to the seasonal change in time. This correction signal includes the planned time jump and its direction (+/- 1 hour), as well as an indication relating to the time period remaining until the night and the time scheduled to effect the time change ( for example a period of 15 days, 8 hours and 20 minutes). Thus, the external device includes the resources necessary to know not only the exact real time but also the date. Based on the date when the 'seasonal time change' function is activated, the app easily calculates the aforementioned remaining time period.

When the watch 154 receives the external correction signal with the indication that this signal relates to a next time change, the control logic circuit 60B programs the time counter 160 so that the latter measures the time period. remaining, from a reset signal received from the logic circuit, until the time scheduled for the time change. Alternatively, the start of the time measurement takes place as soon as the clock circuit 162 is activated by the logic circuit after the time counter has been programmed, this activation taking place quickly after the reception of the external correction signal. To perform the seasonal time change on the scheduled night, watch 154 can take advantage of the fact that it can be recharged by the recharging unit of the box 152. Indeed, as the time change is generally scheduled at night, after midnight, the user can put the watch in the box on the night in question and activate the charging of the watch battery (unless this is done automatically). Thus, the watch has sufficient energy to perform the relatively long time correction. For such a correction, the watch will select, depending on the case, either the second mode of correction of an advance by activating the timer 70, after having provided it with the duration of the correction period PAcor, or the generator F2SUP by activating it for a period. correction PRcor calculated for a delay corresponding to the jump of '1 hour'. For example, the ratio RS = F2Cor / FOc is expected to be greater than 1.10 and preferably greater than 1.15. As indicated above, the first mode of correcting a delay makes it possible to correct for example 1 hour during a correction period of 6 hours. We can even consider correcting 1 hour in 5 hours.

It will be noted that the braking device can be formed by an actuator of another type than that described above, in particular by an actuator of the electromagnetic type comprising a magnet-coil coupling system provided to directly brake the mechanical resonator, at least one magnet being fixed to the balance of the resonator or to its support and at least one coil being respectively carried by this support or the balance of the resonator.

With reference to Figures 16 to 18, a sixth embodiment of a timepiece according to the invention will be described below. This sixth embodiment is arranged to allow the implementation of the second mode of correcting a lead, already described in previous embodiments, and a second mode of correcting a delay which will be described here in detail.

[0117] The timepiece 170 according to the sixth embodiment is shown in part in Figure 16, where only the mechanical resonator 14A of the mechanical movement is shown. Apart from the device for correcting the displayed time, the other elements of the timepiece are similar to those shown in Figure 1. The mechanical resonator comprises a balance 16A associated with a spiral spring 15. The balance comprises a rim 20A which has a projecting part 190 rising radially at its periphery. No other element of the balance rises to the radial position of the end part of the protruding part 190.

The balance comprises a mark 191 formed of a non-symmetrical succession of bars having reflection coefficients different from the light coming from an optical sensor 192 or simply a different reflection of this light, in particular a succession of at least two black bars of different widths and separated by a white bar, the width of one of the two black bars being equal to the sum of the widths of the other black bar with the white bar. It will be understood that the bars thus form a sort of code with a transition in the middle of the mark 191. Instead of black bars and a white bar, other colors can be taken. In a variant, the black bars correspond to matt areas of the serge, while the white bar corresponds to a polished area of this serge. The black bars can also correspond to notches in the serge which present an inclined plane. Several variants are therefore possible. Note that the mark 191 has been shown on the top of the rim for its description, but in the variant shown it is located on the outer lateral surface of the rim since the optical sensor is arranged in the general plane of the balance 16A . In another variant, the mark is located as shown, on the upper or lower surface of the rim, and the sensor is then rotated by 90 ° in order to be able to illuminate this mark.

The optical sensor 192 is arranged to detect the passages of the oscillating resonator by its neutral position (corresponding to the angular position '0' for the projecting part 190) and to make it possible to determine the direction of movement of the balance during each passage by this neutral position. This optical sensor comprises an emitter 193 of a light beam in the direction of the serge 20A, this emitter being arranged so that it illuminates the mark 191 when the resonator passes through its neutral position, and a light receiver 194 arranged to receive at the minus a part of the light beam which is reflected by the serge at the level of the mark. The optical sensor thus forms a device for detecting a specific angular position of the balance, allowing the electronic control unit to determine a specific instant at which the oscillating mechanical resonator is in the specific angular position, and also a device for determining of the direction of movement of the balance during the passage of the oscillating resonator through the specific angular position, Other types of position detector and of the direction of movement of the resonator can be provided in other variants, in particular capacitive or inductive detectors.

[0120] Next, the timepiece 170 comprises a resonator braking device which is formed by an electromechanical device 174 with a bistable movable stop. An alternative embodiment, by way of non-limiting example, is shown in FIG. 16. The electromechanical device 174 comprises an electromechanical motor 176, of the watchmaking stepper motor type of small dimensions, which is supplied by a circuit d. 'power supply 178, which comprises a control circuit arranged to generate, when it receives a control signal S4Cmd, a series of three electrical pulses which are supplied to the coil of the motor so that its rotor 177 advances one step at a time. each electrical impulse, or half a turn of rotation. The series of three electrical pulses is designed to drive the rotor rapidly, continuously or almost continuously. The rotor pinion meshes with an intermediate wheel 180 which meshes with a wheel having a diameter equal to three times that of the rotor pinion and fixedly bearing a first bipolar permanent magnet 182. Given the diameter ratio between said pinion and the bearing wheel the magnet 182, the latter turns half a turn during a series of three electrical pulses. Thus the first magnet has a first rest position and a second rest position in which the first magnet has a magnetic polarity opposite to that of the first rest position (by 'rest position' is understood a position in which is found magnet 182 after motor 176 has made a series of three electrical pulses on command and its rotor has then ceased to rotate).

[0121] In addition, the actuator 174 comprises a bistable rocker 184 pivoted about an axis 185 fixed to the mechanical movement and limited in its rotation by two pins 188 and 189. The bistable rocker comprises at its free end, forming the head of this rocker, a second bipolar permanent magnet 186 which is movable and substantially aligned with the first magnet 182, the magnetic axes of these two magnets being provided substantially collinear when the first magnet is in one or the other of its two rest positions. Thus, the first rest position of the first magnet corresponds, relative to the second magnet 186, to a position of magnetic attraction, and its second position of rest corresponds to a position of magnetic repulsion. Each time the control signal S4Cm activates the power supply circuit to perform a series of three electrical pulses, the first magnet turns half a turn and the rocker alternately passes from a stable position of no interaction with the balance of the resonator in a stable position of interaction with this balance in which the rocker 184 then forms a stop for the projecting part 190, which abuts against the head of this rocker when the resonator oscillates and the projecting part reaches the level of this head, whatever the direction of rotation of the balance during the impact.

In the non-interaction position, the movable latch is outside a space swept by the projecting part 190 when the resonator oscillates with an amplitude within its useful operating range. On the other hand, in the interaction position, the movable latch is located partially in this space swept by the projecting part and thus forms a stop for the resonator. The term “stable position” is understood to mean a position in which the latch remains in the absence of a power supply to the motor 176 which serves to actuate the latch between its two stable positions, in both directions. The rocker thus forms a bistable movable stop for the resonator. This rocker therefore forms a retractable stop member for the resonator. The actuator 174 is arranged so that the latch can remain in the non-interacting position and in the interacting position without maintaining power to the motor 176.

The stop member in its interaction position and the protruding part define a first angular stop position θB for the balance of the oscillating resonator which is different from its neutral position, the protruding part abutting against the stop member at this first angular stop position when it arrives from its angular position '0', corresponding to the neutral position of the resonator, during a second half-wave of a first determined alternation among the two half-waves of each period d oscillation of the resonator. Then, the angle θB is expected to be less than a minimum amplitude of the oscillating mechanical resonator in its useful operating range. In addition, the angle θB is provided so that the oscillating resonator is stopped by the stop member outside the zone of coupling of the oscillating resonator with the escapement of the mechanical movement, which has already been described. The stop member in its interacting position and the protruding part also define a second angular stop position, close to the first but greater than the first, for the balance of the oscillating resonator when the protruding part arrives from an angular position extreme of the resonator during a first half-cycle of the second one of the two half-cycles of each period of oscillation. This second angular stop position is also provided less than a minimum amplitude of the mechanical resonator oscillating in its useful operating range.

[0124] It will be noted that the projecting part 190 can, in another variant, rise axially from the rim or from one of the arms of the balance and the bistable electromechanical device 174 is then arranged so that the bistable latch has a movement in a plane parallel to the axis of rotation of the balance. In this other variant, the respective magnetization axes of the two magnets 182 and 186 are axial and remain substantially collinear, the magnet 182 then being arranged under the head of the rocker. It will be noted that such an arrangement of the bistable electromechanical device can also be provided in the context of the variant shown with a projecting part rising radially from the rim. It will be noted that the projecting part of the resonator can, in another variant, be arranged around the shaft of the balance, in particular on the periphery of a plate carried by this shaft or integrally formed with the shaft. In a variant, such a plate is the plate carrying the pin of the escapement.

[0125] Finally, the timepiece 170 comprises an electronic control unit 196 which is associated with the optical sensor 192 and arranged to control the supply circuit 178 of the electromechanical device, to which the unit 196 supplies the control signal S4Cmd . The electronic control unit comprises a control logic circuit 198, a bidirectional time counter 200 and a clock circuit 202. This control unit and the receiver 204 of the external correction signal SEx are associated with the electromechanical device 174 to allow setting. implementation of the second mode of correcting an advance and also of the second mode of correcting a delay in the time indicated by the display of the timepiece, explained below. The term "early" and "late" in the displayed time is understood both as an error detected by an external device, comprising an application specific to the present invention, as well as a jump forward or backward in the displayed time which is required via an external correction signal SExt supplied to the timepiece by an external device, whether this is in particular for a seasonal time change as explained previously or even to effect a time zone change in the event that the user is the timepiece moves from one time zone to another.

To implement the second correction mode implemented in this sixth embodiment, the electronic control unit 196 is arranged to control the electromechanical device (also called 'actuator' or 'electromechanical actuator') so that ' it can selectively actuate the stop device (the flip-flop 184), depending on whether it is intended to correct a delay or an advance in the time displayed by the timepiece, so that this stop device is moved by its non-interaction position to its interaction position respectively before the projecting part 190 reaches said first angular stop position θB during said second half-cycle of said first cycle of an oscillation period and before the protruding portion 190 does not reach said second angular stop position during said first half-cycle of said second half-cycle of an oscillation period.

In general, to correct at least in part an advance (positive time error), the electromechanical device is arranged so that, when the stop member is actuated to stop the mechanical resonator in a first half-wave, the stop member momentarily prevents, after the projecting part has butted against this stop member, the mechanical resonator from continuing the natural oscillation movement specific to this first half-wave, so that this natural oscillation movement at the The course of the first half-cycle is momentarily interrupted before it is continued, after a certain blocking period which ends with the withdrawal of the stop member. Preferably, in the case of a bistable electromechanical device as described above, provision is made to correct substantially the whole of a positive time error, determined by an external correction signal supplied to the timepiece according to the invention, during a continuous blocking period defining a correction period, which is provided substantially equal to the advance to be corrected. To do this, in the variant described, following the instant of a passage of the resonator through its neutral position during a said second alternation of an oscillation period (alternation where the projecting part 190 arrives at the level of the rocker head 184 before the resonator passes through its neutral position), this second half-wave being detected by the optical sensor 192 thanks to the arrangement provided for detecting the direction of the oscillation movement during the detection of the passages of the resonator by its neutral position, the electronic control unit waits for a delay of TOc / 4 to be reached to activate the actuator so that it drives, via its motor, the rocker 184 from its stable non-interaction position to its position stable interaction where the head of the rocker forms a stop for the protruding part. Depending on the value of the angular stop position, for example between 90 ° and 120 °, it is possible to provide a shorter delay than T0c / 4, for example TOc / 5, to trigger a series of three electrical pulses allowing '' drive the motor 176 so that its rotor turns rapidly by one and a half turns, the time interval to allow the rocker to pivot between its two stable positions, by reversing the direction of the magnetic flux generated by the magnet 182, thus being elongated. In the latter case, it must be ensured that the protruding part has indeed exceeded the angular stop position in the half-wave preceding the first half-cycle during which it is intended to block the resonator during a correction period.

In general, to correct at least in part a delay (negative time error), the electromechanical device is arranged so that, when the stop member is actuated to stop the mechanical resonator in a second half-wave of 'at least one said first alternation of a period of oscillation (alternation during which the projecting part 190 arrives at the level of the head of the rocker 184 after the passage of the resonator through its neutral position), it thus terminates prematurely to this second half-wave without blocking the resonator but by reversing the direction of the oscillation movement of this resonator, so that the mechanical resonator begins, following an instantaneous or almost instantaneous stop caused by the collision of the projecting part with the organ of stop, directly a following alternation. Thus, in the context of the second mode of correcting a delay, the position detector and the direction of movement of the resonator and the electronic control unit are arranged so as to be able to activate the actuator, each time the external signal correction received by the receiving unit corresponds to a delay in the displayed time, so that this actuator actuates its stop member so that the projecting part of the oscillating resonator abuts against this stop member in a plurality of halves. alternations of the oscillation of the mechanical resonator which each follow its passage through the neutral position, so as to prematurely end each of these half-vibrations without blocking the mechanical resonator. The number of half-waves of said plurality of half-waves is determined by the delay to be corrected.

In a preferred variant shown in Figures 17 and 18, the electronic control unit and the actuator are arranged so that, to at least partially correct a delay, the latch is maintained in its interaction position, following an actuation of this rocker from its non-interaction position to its interaction position while the oscillating resonator is located angularly on the side of its neutral position relative to the angular stop position, until the end of the period of correction during which the projecting part of the oscillating mechanical resonator periodically abuts several times against the head of the rocker, the duration of the correction period during which the rocker is maintained in its interaction position being determined by the delay to be corrected . The pivoting of the rocker from its non-interaction position to its interaction position can take place either in a so-called first alternation (that in which the impact with the projecting part is provided, this first alternation being detected by the detection of the direction of rotation of the balance) preferably directly after the detection of the passage through the neutral position so that the rocker is placed in its interaction position before the projecting part reaches the stop angle θB, or in a so-called second alternation (also detected by detecting the direction of rotation of the balance) directly after the detection of passage through the neutral position, this second variant leaving more time to actuate the rocker and allow it to be placed in a stable manner in its interaction position (l the stop angle is by definition less than or equal to 180 °). For example, if θB = 120 ° and the amplitude of the free oscillation of the resonator θL = 270 °, then we have in the second variant a time interval corresponding to a rotation between the angle '0' and a slightly less than 240 ° (360 ° -120 °), i.e. approximately 230 ° if the angle θT to the axis of rotation defined by the head of the rocker is approximately 10 °, to perform the pivoting of the rocker (so as to do not block the balance by going beyond the position of the projecting part in the second cycle); whereas in the first variant there is only one time interval corresponding to a rotation between the angle '0' and 120 °. Note that if θL <360 ° - θB- θT, then we have much more time in the second variant to perform the pivoting of the rocker.

In general, to determine the duration of a delay correction period, the electronic control unit comprises a measuring circuit associated with the optical sensor, this measuring circuit comprising a clock circuit, providing a clock signal at a determined frequency, and a comparator circuit making it possible to measure a time drift of the oscillating resonator relative to its reference frequency, the measuring circuit being arranged to be able to measure a time interval corresponding to a time drift of the resonator mechanical since the start of the correction period. The electronic control unit is arranged to end the correction period as soon as said time interval is equal to or slightly greater than a time error which is supplied by the external correction signal.

In the variant described in laFigure 16, the measuring circuit comprises a clock circuit 202, supplying a periodic digital signal at the frequency F0c / 2, and a bidirectional counter 200 (reversible counter). This bidirectional counter receives at its input '-' the periodic signal of the clock circuit (generating a decrementation of this counter by two units for each set period T0c = 1 / FOc) and at its input '+' a digital signal from the optical sensor 192 which comprises a pulse or a logical change of state on each passage of the resonator 14A through its neutral '0' position. As such a passage occurs in each half-wave of the oscillating resonator, the counter 200 is incremented by two units at each period of oscillation. Thus the state of the counter (integer number MCb) is representative of a time drift of the mechanical resonator relative to the reference frequency which is determined by the clock circuit having the precision of a quartz oscillator. The whole number MCb corresponds to the number of additional alternations performed by the resonator, from an initial instant when the reversible counter is reset, relative to a case of an oscillation at the setpoint frequency.

The logic control circuit 198 receives from the optical sensor 192 a digital signal allowing this logic circuit to determine the passages of the resonator by its neutral position and the direction of the oscillation movement at each of these passages. To correct a given delay, following a detection of a passage of the resonator through its neutral position as described above, the control logic circuit, on the one hand, activates the actuator 174 so that it actuates the rocker towards its interaction position and, on the other hand, resets (performs a 'reset') the clock circuit 202 and the bidirectional counter 200, which defines the start of a correction period. It will be noted that this reinitialization can, in a variant, take place before the power supply of the actuator 174 to effect the pivoting of the rocker, but after the electronic control unit 196 and the optical sensor 192 are activated. In a variant, the reinitialization of the clock circuit is not provided. In other variants, the optical sensor is replaced by another type of sensor, for example of the magnetic or capacitive type. In a specific variant, the detector of the passage of the mechanical resonator through its neutral position is formed by a miniaturized sound sensor (MEMS type microphone) capable of detecting the sound impulses generated by the shocks between the ankle of the balance and the fork of the balance. anchor forming the escapement of the mechanical movement.

The number of alternations at the reference frequency F0c in a negative time error TERR (given delay) is equal to -TErr · 2 · F0c. Thus, as soon as the number MCbd of the bidirectional counter reaches this value or exceeds it slightly (because this value is not in all cases an integer), the given delay is made up and the time display is correct again. (it then gives the real time precisely, in particular with a precision of one second). The logic control circuit is therefore designed to be able to compare the state of the counter with the value -TErr 2 F0c, and to end the correction period as soon as it detects that the number MCb is equal to or greater than this value. , by controlling the supply circuit 178 of the actuator so that the latter actuates the rocker from its stable interaction position to its stable non-interaction position.

[0134] In Figures 17 and 18 are shown the oscillations of the resonator 14A, respectively in two extreme particular cases of the preferred variant described above, at the start of a period for correcting a given delay. FIG. 17 relates to the case where the kinematic energy of the resonator is entirely absorbed during each impact between the projecting part of the balance and the head of the stop. The free oscillation 210 has in particular a second free alternation A2L before a detection of a time t0 when the resonator passes through its neutral position (position '0' of the projecting part 190) in the first alternation which follows, the time t0 marking the start of 'a correction period for a given delay. The latch is moved into its interaction position directly after time t0. Following the first shock between the projecting part and the latch, a relatively large positive phase shift DP1 is obtained between the fictitious free oscillation 211 and the oscillation 212. Then a stable phase is established where the oscillation 212 is abbreviated, relatively to a fictitious free oscillation 213 since the previous stop of the resonator by the stop member, in the second half-cycle of the first half-wave A1 of each oscillation period; which then results in a positive phase shift DP2 smaller than DP1. The second half-wave A2 of oscillation 212 is not disturbed by the latch.

[0135] Figure 18 relates to a particular case of a hard shock or elastic shock between the projecting part and the head of the lever. In this case the kinetic energy of the resonator is conserved at each impact, given that there is no dissipation of kinetic energy during the shocks, but only a reversal of the direction of the oscillation movement. The amplitude of the oscillation 216 during the correction period thus remains identical to that of the free oscillation 210, and therefore of the fictitious free oscillation 217 for each period of oscillation. Following time t0s, a stable phase is established with alternations A1 * and A2 * of duration T2 much less than T0 / 2, generating a relatively large positive phase shift DP3 at each oscillation period. To obtain an elastic shock, provision can be made for the lever to have a certain elasticity, in particular for the body of the lever and / or its head to be formed of an elastic material capable of undergoing a certain compression, so as to momentarily absorb water. kinetic energy of the balance to restore it immediately after the reversal of the direction of the oscillation movement. In this case, the oscillation 216 will slightly exceed the stop angle θB. In another more sophisticated variant, it is the projecting part which is elastically mounted on the rim of the balance. For example, the protruding part has a base forming a slide arranged in a circular slide machined in the rim and an elastic element, in particular a small coil spring is arranged in the slide at the rear of the slide, that is to say. say the other side of the rocker head relative to the protrusion when it is in its angular '0' position. In practice, the shocks between the projecting part of the balance and the stop of the electromechanical device generally occur in a manner which corresponds to a physical situation between the two extreme situations described in Figures 17 and 18.

Finally, in another embodiment, the electromechanical device is formed by a monostable electromechanical actuator which comprises a movable finger arranged so that this movable finger can be moved alternately between a first radial position and a second radial position when this actuator is respectively not activated (not supplied) and activated (i.e. it is supplied). The first radial position of the finger corresponds to a position of non-interaction with the balance of the oscillating resonator and its second radial position corresponds to a position of interaction with the oscillating balance in which this finger then forms a stop for the projecting part of the oscillating balance. , similarly to the head of the rocker 184.

Claims (23)

1. Timepiece (2; 112; 132; 154; 170) comprising: - a display of a real time (12), - a mechanical movement (4; 4A; 92) which comprises a drive mechanism (10) of the display and a mechanical resonator (14; 14A) which is coupled to the drive mechanism so that its oscillation cycles the march of this drive mechanism, - a device for correcting the real time which is indicated by the display; characterized in that the device for correcting the displayed real time is formed by: - a reception unit (30,30A; 30B; 204) of an external correction signal (SExt) for the displayed real time, - an electronic control unit (28,28A; 28B; 196), and - a braking device (22; 22A; 22A, 106; 22B, 114; 24C, 26C; 22C; 174) of the mechanical resonator; the electronic control unit being arranged to be able to process the information contained in the external correction signal and to control the braking device as a function of this information; and in that the real time correction device is arranged so that, when the external correction signal received by the timepiece requires a correction of the displayed real time, the braking device can act on the mechanical resonator, during a correction period, to vary the rate of the drive mechanism so as to effect at least the major part, preferably substantially all of the required correction. 2. Timepiece according to claim 1, characterized in that it comprises a device (144; 192) for determining the passage of the oscillating mechanical resonator through at least one specific position, the device for determining this specific position of the resonator. mechanical allowing said electronic control unit to determine a specific instant at which the oscillating mechanical resonator is in said specific position; and in that the electronic control unit is arranged so that a first activation of the braking device occurring at the start of the correction period, to generate a first interaction between this braking device and the mechanical resonator, is triggered in function of said specific instant. 3. Timepiece according to claim 2 wherein the horological movement comprises an escapement associated with the mechanical resonator; characterized in that the braking device comprises an actuator (174) provided with a stop member (184) for the oscillating mechanical resonator, the stop member being operable between a position of non-interaction with the mechanical resonator and an interaction position in which this stop member forms a stop for a protruding part (190) of the oscillating mechanical resonator, the protruding part being arranged to abut against the stop member when the latter is in its interaction position , the stop member in its interaction position and the protruding part defining a stop position (θB) for the oscillating mechanical resonator which is different from its neutral position, corresponding to the state of minimum potential energy of the mechanical resonator , and less than a minimum amplitude of the oscillating mechanical resonator in its useful operating range; in that said stop position is further provided so that the oscillating mechanical resonator is stopped by the stop member outside a coupling zone (θZI) of the escapement with oscillating mechanical resonator; and in that the circuit for determining said specific position of the oscillating mechanical resonator and the electronic control unit are arranged so as to be able to activate the actuator, when the external correction signal (SExt) received by the receiving unit corresponds to a delay in the displayed time that it is planned to correct, so that this actuator actuates its stop member so that the projecting part (190) of the oscillating mechanical resonator abuts against this stop member (184) in a plurality of half-waves of the oscillating mechanical resonator which each follow its passage through said neutral position, so as to prematurely end each of these half-waves without blocking the mechanical resonator, the number of half-waves of said plurality of half-waves or a duration of the correction period during which the stop member is maintained in its interaction position being determined by said delay to be corrected r. 4. Timepiece according to claim 3, characterized in that the device for determining said specific position of the oscillating mechanical resonator comprises a detector (192) for the position and direction of movement of the mechanical resonator, this detector and the mechanical resonator. being arranged to allow the detection of the passage of the oscillating mechanical resonator through said specific position ('0') in each period of its oscillation and to allow the electronic control unit (196) to determine the direction of movement of the oscillating mechanical resonator in the alternation during which a detection of the passage of the oscillating mechanical resonator through said specific position is carried out; and in that the electronic control unit is designed to be able to at least partially correct said delay, so that this unit can control the actuator (174) so that this actuator actuates its stop member from its non-interaction position to its interaction position while the oscillating mechanical resonator is located on the side of its neutral position relative to said stop position, and so that the actuator then maintains the stop member in this interaction position for a determined period which is sufficient for the projecting part of the oscillating mechanical resonator to abut at least once against the stop member. 5. Timepiece according to claim 4, characterized in that said actuator (174) is of the bistable type and is arranged to be able to remain in the non-interaction position and in the interaction position without maintaining a supply of this. actuator; and in that the electronic control unit and the actuator are arranged so that, in order to at least partially correct said delay, the stop member (184) is maintained in its interacting position, following an actuation of the stop member from its non-interaction position to its interaction position while the oscillating mechanical resonator is located on the side of its neutral position relative to said stop position, until the end of said correction period at during which the projecting part (190) of the oscillating mechanical resonator periodically abuts several times against the stop member. 6. Timepiece according to claims 4 or 5, characterized in that the electronic control unit comprises a measuring circuit which is associated with said detector, this measuring circuit comprising a clock circuit (202), providing a clock signal at a determined frequency (FOc / 2), and a comparator circuit (200) making it possible to measure a time drift of the oscillating mechanical resonator relative to its reference frequency, the measuring circuit being arranged to be able to measure an interval of time corresponding to a time drift of the mechanical resonator from the start of the correction period, the electronic control unit being arranged to end the correction period as soon as said time interval is equal to or greater than a time error which is provided by the external correction signal. 7. Timepiece according to claim 1 or 2, characterized in that the braking device is formed by an electromechanical actuator (22,22A; 22B; 22C; 24C & 26C) which is arranged to be able to apply braking pulses. to the mechanical resonator, and the electronic control unit comprises a generator device of at least one frequency (62,62A, 62B) which is arranged so as to be able to generate a first periodic digital signal (SFS, SFS1, SFS2) at a FSUP frequency; in that the electronic control unit is arranged to provide the braking device, when the external correction signal received by the reception unit corresponds to a delay in the displayed time which it is intended to correct, a first control signal (SC1, SAct (SFS), S1Cmd (SFS1, SFS2)) derived from the first periodic digital signal, during a first correction period, to activate the braking device so that this braking device generates a first series periodic braking pulses which are applied to the mechanical resonator at said FSUP frequency, the duration of the first correction period and therefore the number of periodic braking pulses in said first series being determined by said delay to be corrected; and in that the frequency FSUP is provided and the braking device is arranged so that said first series of periodic braking pulses at frequency FSUP can generate, during said first correction period, a first synchronous phase in which the oscillation of the mechanical resonator (14) is synchronized to a correction frequency FScor which is greater than a reference frequency F0c provided for the mechanical resonator. 8. Timepiece according to claim 7, characterized in that said frequency FSUP can take, as a function of said delay to be corrected, at least two different values F1SUP and F2SUP; in that said device for generating at least one frequency is a device for generating frequencies which is arranged so as to be able to generate said first periodic digital signal selectively at the frequency F1SUP and at the frequency F2SUP; and in that the frequencies F1SUP and F2SUP are provided so that said correction frequency FScor takes two different values F1 cor and F2cor respectively for the two frequencies F1SUP and F2SUP with F2cor greater than F1cor, the selection of the frequency F1SUP being carried out when said delay is less than a given value while the selection of the frequency F2SUP is carried out when said delay is equal to or greater than this given value. 9. Timepiece according to claim 7 or 8, characterized in that said generator device of at least one frequency is a frequency generator device (62,142; 62A, 62B, 142) which is arranged so as to be able to further generating a second periodic digital signal (SFI) at a frequency; in that the electronic control unit (28B; 28C) is arranged to be able to supply to the braking device, when the external correction signal received by the reception unit corresponds to an advance in the displayed time that it is planned to correct, a second control signal (SAct (SFI), S1Cmd (SFI)) derived from the second periodic digital signal, during a second correction period, to activate the braking device so that this braking device generates a second series of periodic braking pulses which are applied to the mechanical resonator at said frequency FINF, the duration of the second correction period and therefore the number of periodic braking pulses in said second series being determined by said advance to be corrected; and in that the frequency is provided and the braking device is arranged so that said second series of periodic braking pulses at the frequency can generate, during said second correction period, a second synchronous phase in which the oscillation of the mechanical resonator is synchronized to a correction frequency Flcor which is lower than the reference frequency F0c provided for the mechanical resonator. 10. Timepiece according to claims 7 or 8, wherein the watch movement comprises an escapement associated with the mechanical resonator; characterized in that said FSUP frequency and the duration of the braking pulses of the first series of periodic braking pulses are selected such that, during said first synchronous phase, the braking pulses of said first series each occur out of a coupling zone (Θzi) between the oscillating mechanical resonator and the escapement. 11. Timepiece according to claim 9, wherein the horological movement comprises an escapement associated with the mechanical resonator; characterized in that said frequency and duration of the braking pulses of the second series of periodic braking pulses are selected such that, during said second synchronous phase, the braking pulses of said second series each occur out of a coupling zone (θZI) between the oscillating mechanical resonator and the exhaust. 12. Timepiece according to any one of claims 7 to 11, characterized in that the generator device of at least one frequency is a frequency generator device (62,142,144; 62A, 62B, 142, 144) which is arranged so in addition to being able to generate a third periodic digital signal (SF0c) at the reference frequency F0c for the mechanical resonator; in that the electronic control unit is arranged to be able to supply the braking device with a third control signal (SAct (SF0c), S1Cmd (SF0c)) derived from the third periodic digital signal, during a preliminary period preceding the correction period , to activate the braking device so that this braking device generates a preliminary series of periodic braking pulses which are applied to the mechanical resonator at the setpoint frequency FOc, the duration of these braking pulses and the braking force applied to the oscillating mechanical resonator during the preliminary series of periodic braking pulses being provided so that none of these braking pulses can stop the oscillating mechanical resonator in a coupling zone (Θzi) of the oscillating mechanical resonator with the escapement ; in that the electronic control unit is arranged so that the duration of the preliminary period and the braking force applied to the oscillating mechanical resonator during the preliminary series of periodic braking pulses make it possible to generate at least at the end of the preliminary period a preliminary synchronous phase in which the oscillation of the mechanical resonator is synchronized on the reference frequency F0c; and in that the electronic control unit is arranged so that the triggering of a first braking pulse of the first series of periodic braking pulses, during said correction period, occurs after a relatively determined time interval. at an instant at which the last braking pulse of the preliminary period is triggered, the instant at which said first braking pulse is triggered and the braking force applied to the oscillating mechanical resonator during said first series of periodic braking pulses being provided so that said first phase synchronous with said correction frequency FScor starts from said first braking pulse or a second braking pulse. 13. Timepiece according to any one of the preceding claims, characterized in that it comprises a locking device (22; 106; 114; 174) of the mechanical resonator; and in that the electronic control unit is arranged to be able to supply the blocking device, when the external correction signal received by the reception unit corresponds to an advance in the displayed time which it is intended to correct, a fourth control signal which activates the blocking device so that this blocking device blocks said oscillation of the mechanical resonator during said correction period which is determined by said advance to be corrected, so as to stop the operation of said drive mechanism during this correction period. 14. Timepiece according to claim 13, characterized in that said correction period has a duration substantially equal to said advance to be corrected. 15. Timepiece according to claim 13 or 14, characterized in that the locking device is formed by a separate device (114) from said braking device and comprises a bistable latch (115), the first stable position of this latch bistable corresponding to a position of non-interaction with the mechanical resonator and its second stable position corresponding to a stop and blocking position of the mechanical resonator. 16. Timepiece according to any one of claims 13 to 15, characterized in that the locking device (106) forms a lock for the mechanical resonator, a part (107) of this locking device being inserted into a hollow (108), arranged in a circular element (100) of the balance forming the mechanical resonator, when the blocking device is activated to block this mechanical resonator during the period of correction of a given advance. 17. Timepiece according to any one of the preceding claims, characterized in that said correction of the displayed time relates to a temporal error detected in the displayed time by an external device capable of supplying said timepiece to the timepiece. external correction signal. 18. Timepiece according to any one of claims 1 to 16, characterized in that said correction of the displayed time relates to a change in time zone or to a seasonal change in the time. 19. Timepiece according to claim 18, characterized in that it further comprises a measuring circuit, formed of a programmable time counter and a clock circuit, for measuring a time interval remaining between a reception of an external correction signal relating to a seasonal change and a date and time scheduled to effect this seasonal change. 20. An assembly formed by a timepiece according to any one of the preceding claims and by an external device (40; 152) comprising an emitter (52) of said external correction signal; characterized in that the external device comprises: - a photographic device (44; 1156) comprising a photographic sensor formed by an array of photo-detectors, an image processing algorithm which is designed to be able to determine the position of at least one determined hand of said display of the timepiece in an image taken by the photographic device, and - a time base (48) capable of providing the exact real time. 21. Assembly according to claim 20, characterized in that the external device (40; 152) further comprises an algorithm for calculating a temporal error between a first temporal datum, indicated by the display at a given instant and detected by the external device via its photographic sensor and its image processing algorithm, and a second temporal datum corresponding to the first temporal datum and supplied substantially to said instant given by said time base; and in that, when provision is made to correct said determined temporal error, the external correction signal supplied by the device external to the timepiece comprises information relating to this temporal error. 22. An assembly according to claim 20 or 21, characterized in that the external device is a portable telephone (40). 23. Assembly according to claim 20 or 21, characterized in that the external device is incorporated in a box (152) provided for the timepiece and comprising a housing for receiving the timepiece (154) in a given position. .