EP3842876A1 - Timepiece fitted with a mechanical movement and a device for correcting the time displayed - Google Patents

Abstract

The watch (2) is formed by a mechanical movement incorporating a mechanical resonator (14). It comprises: - a display of the real time (12), - a correction device (6) formed by a device (30) for detecting the passage of at least one hand through at least one reference time position and by an electronic correction circuit (40) making it possible to determine an overall time error for the display, and - a braking device (22A) of the mechanical resonator. The correction device is designed to be able to correct the actual time displayed as a function of the overall time error (delay or advance) determined beforehand. To do this, the correction device is arranged so that the braking device can act on the mechanical resonator during a correction period to vary the rate of the display drive mechanism, so as to correct the speed. actual time displayed.

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 displayed 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 so as to be able to act, in the pulled position, on a driving wheel set. 'hour indicator and 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

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 these timepieces comprising a mechanical movement. In particular, the present invention aims to be able to set the real time of a timepiece, comprising a mechanical movement and a time display, with a precision corresponding at least to that of an electronic watch, of preferably set this timepiece to the exact real time which is given by an external system arranged to supply it (in particular a system connected to an atomic clock), without requiring that a user or a robot must actuate a rod. crown or another external control member of the timepiece in order to set the time of the display itself. 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 assessment 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. The real time will also be mentioned simply by the term 'the hour', in particular as regards the real time displayed by a timepiece. To indicate the legal time given with great precision, in particular by / via a GPS system, a telephone network, a long-distance transmission antenna or a computer / portable device connected in particular to a server on the Internet network receiving the real time of 'a high precision clock, we will use the expression' exact real time 'in this text.

• un affichage d'une heure réelle formé par un ensemble d'indicateurs comprenant un indicateur qui est relatif à une unité temporelle donnée de l'heure réelle et qui indique l'unité temporelle courante correspondante,
• un mouvement mécanique formé par un mécanisme d'entraînement de l'affichage et un résonateur mécanique qui est couplé au mécanisme d'entraînement de manière que son oscillation cadence la marche de ce mécanisme d'entraînement, et
• un dispositif de correction de l'heure réelle qui est indiquée par l'affichage ;

dans laquelle le dispositif de correction de l'heure réelle affichée comprend :

• un dispositif de détection agencé pour permettre la détection, de manière directe ou indirecte, du passage dudit indicateur de l'affichage par au moins une position temporelle de référence de cet affichage qui est relative à ladite unité temporelle de l'heure réelle ;
• un circuit électronique de correction, et
• un dispositif de freinage du résonateur mécanique ;

dans laquelle le circuit électronique de correction comprend :

• une unité de commande agencée pour pouvoir commander le dispositif de détection de sorte que ce dispositif de détection effectue, durant une phase de détection, une pluralité de mesures successives et fournisse une pluralité de valeurs de mesure correspondantes,
• une unité de traitement agencée pour pouvoir recevoir du dispositif de détection ladite pluralité de valeurs de mesure et la traiter, et
• une base de temps interne comprenant un circuit d'horloge et générant un temps réel de référence composé au moins d'une unité temporelle courante de référence correspondant à ladite unité temporelle courante de l'heure réelle affichée.

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 a real time formed by a set of indicators comprising an indicator which relates to a given time unit of the real time and which indicates the corresponding current time unit,
• a mechanical movement formed by a drive mechanism for the display and a mechanical resonator which is coupled to the drive mechanism so that its oscillation cycles the operation of this drive mechanism, and
• a device for correcting the real time which is indicated by the display;

in which the device for correcting the displayed real time comprises:

• a detection device arranged to allow the detection, directly or indirectly, of the passage of said indicator of the display through at least one reference time position of this display which is relative to said time unit of the real time;
• an electronic correction circuit, and
• a mechanical resonator braking device;

in which the electronic correction circuit comprises:

• a control unit arranged to be able to control the detection device so that this detection device performs, during a detection phase, a plurality of successive measurements and provides a plurality of corresponding measurement values,
• a processing unit designed to be able to receive said plurality of measurement values from the detection device and process it, and
• an internal time base comprising a clock circuit and generating a real reference time composed of at least one current reference time unit corresponding to said current time unit of the displayed real time.

Then, according to the invention, the electronic correction circuit is arranged and the duration of the detection phase is provided to allow the detection device to detect, while the drive mechanism is running and clocked by the oscillating mechanical resonator, at least one passage of said indicator through any reference time position of said at least one reference time position. The electronic correction circuit is designed to be able to determine at least one moment of passage of said indicator through said any reference temporal position on the basis of at least one measurement value of the plurality of measurement values, this moment of passage being determined. by the internal time base and composed at least of the value of said current reference time unit at said passing instant. Said electronic correction circuit is furthermore arranged to be able to determine a temporal error of said indicator, by comparing said at least one passing instant with said reference temporal position, and an overall temporal error for the display (namely for the whole indicators) as a function at least of said temporal error of said indicator.

In addition, according to the invention, the control unit is arranged to be able to control the braking device as a function of the determined overall time error. The device for correcting the displayed real time is arranged so that, when a non-zero overall time error has been determined by the electronic correction circuit, the braking device can act, during a correction period, on the mechanical resonator, as a function of the overall time error, to vary the rate of the display drive mechanism so as to at least partially correct this overall time error, advantageously for the most part this overall time error and preferably substantially the whole thereof.

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 temporarily blocking) such a resonator. . The braking device can be formed by one or more braking units (one or more actuators). In the event that the device brake unit is formed of several brake units, in particular two brake units, each brake unit is selected to act on the mechanical resonator in a specific situation relating to the required correction, in particular a first brake unit to correct a delay and a second braking unit for correcting 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 rotational speeds 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 we consider a resonator in its activated state, in which it oscillates while being maintained, via an exhaust, by a source of mechanical energy.

Although the indicators used to display the real time all relate to one and the same physical quantity, time, in this description we consider the hour, the minute and the second as three different time units given that they are respectively associated with three distinct indicators. The real time displayed by a display is made up of a current hour, a current minute and a current second which will sometimes be qualified as 'displayed'. The current second displayed has an entire part in seconds and possibly one or more decimal places (dial generally without decimal graduation, but the decimal part is a fact in an analog display where the almost continuous advance of the hand is normally done by not clocked by the escapement at twice the frequency of the oscillating resonator). The current minute displayed has an integer part in minutes (whole number of minutes) and generally a fractional part (sexagesimal part) in seconds (always the case in an analog display of real time). The current time displayed includes at least an integer part (and only this whole part with a 'jumping' hour). The real reference time supplied by an internal time base of the electronic type is composed of a current reference second, a reference current minute and a reference second. These three components are whole numbers. In addition, the internal time base can optionally provide fractions of a second. In general, the internal time base, which is of the electronic type, provides a real reference time which can be composed of less time units than the real time, in particular containing only the current reference minute and the current second. reference, possibly in addition a current fraction of a second generated by a clock circuit which forms this internal time base.

In a main embodiment of the invention, the display comprises an hour indicator giving the current time, a minute indicator giving the current minute and a seconds indicator giving the current second of the actual time displayed; and the real reference time generated by the internal time base is made up of at least one current reference second and one current reference minute. The detection device is designed to be able to detect the passage of the seconds indicator through at least a first reference time position of the display and the passage of the minutes indicator through at least a second reference time position of this display. The electronic correction circuit is arranged and the duration of the detection phase is provided to allow the detection device to detect during this detection phase, while said drive mechanism is running and clocked by the oscillating mechanical resonator. , at least one passage of the seconds indicator through a first reference time position of said at least one first reference position and at least one passage of the minutes indicator through a second reference time position of said at least one second reference time position.

Then, the electronic correction circuit is arranged to be able to determine, in association with the internal time base and on the basis of measurement values of the plurality of measurement values, at least a first moment of passage of the seconds indicator. by said first reference temporal position, this first passing instant being determined by the real reference time and composed of at least the value of the second reference current at said first passing instant, and at least one second passing instant of the minute indicator by said second reference time position, this second passing instant also being determined by the real reference time and composed of at least the value of the current reference minute at said second passing instant. In addition, the processing unit or the control unit is designed to be able to determine a first time error for the seconds indicator, by comparing said at least a first moment of passage with the first reference time position, and a second time error for the minutes indicator by comparing said at least one second passing instant with the second reference time position. The processing unit or the control unit is further arranged to be able to determine an overall time error for the display as a function of the first time error and the second time error as well as at least one predetermined processing criterion. for these first and second time errors.

In a particular variant, during the detection phase, the detection device is activated so as to perform the plurality of successive measurements at at least one measurement frequency determined by the clock circuit of the internal time base, this circuit clock supplying a periodic digital signal at the measurement frequency directly to the detection device or indirectly to this detection device via the control unit.

In an advantageous embodiment, the detection device is arranged in the timepiece so as to be able to perform a direct detection of the passage of an indicator of the display through at least one corresponding reference time position, this indicator being arranged to be able to be detected itself by the detection device.

In another embodiment, the detection device is arranged in the timepiece so as to be able to perform an indirect detection of the passage of an indicator of the display through at least one corresponding reference time position, the monitoring device. detection being arranged to be able to detect at least one respective angular position of a wheel integral with the indicator or of a detection wheel, forming the drive mechanism or complementary thereto, which drives or is driven by the wheel integral with the indicator, the detection wheel being selected or configured so as to have a rotational speed lower than that of the wheel integral with the indicator and a gear ratio R equal to a positive integer.

In an advantageous variant of the previous embodiment, the indicator considered is a minute indicator and the detection wheel is formed by a timer wheel which is rotated by a roadway carrying this minute indicator. The detection device comprises at least one detection unit associated with the minute indicator and arranged to be able to detect at least a first series of R periodic angular positions of the timer wheel, two adjacent angular positions of the first series having between them a central angle equal to 360 ° / R.

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 control unit comprises a device for generating at least one frequency which is arranged at so as to be able to generate a periodic digital signal at a frequency F _SUP . The control unit is arranged to supply the braking device, when the overall time error determined beforehand by the electronic correction circuit corresponds to a delay in the displayed time which it is intended to correct, a control signal derived from the periodic digital signal, during a correction period, to activate the braking device so that the latter generates a series of periodic braking pulses which are applied to the mechanical resonator at the frequency F _SUP . The (duration of the) correction period and therefore the number of periodic braking pulses in the series is determined by the delay to be corrected. The frequency F _SUP is provided and the braking device is arranged so that the series of periodic braking pulses at the frequency F _SUP can generate, during the correction period, a synchronous phase in which the oscillation of the resonator mechanical is synchronized to a correction frequency FScor which is greater than a reference frequency F0c provided for the mechanical resonator.

According to an advantageous variant, in which the watch movement comprises an escapement associated with the resonator, the frequency F _SUP and the duration of the braking pulses of the series of periodic braking pulses are selected so that, during said synchronous phase, the Braking pulses of said series each intervene outside a coupling zone between the oscillating resonator and the escapement.

In a particular embodiment, the timepiece comprises a device for blocking the mechanical resonator. Then, the control unit is arranged to be able to supply the blocking device, when the overall time error determined by the electronic correction circuit corresponds to an advance in the displayed time which it is intended to correct, a signal of control which activates the blocking device so that it blocks the oscillation of the mechanical resonator during a correction period which is determined by the advance to be corrected, in order to stop the operation of the drive mechanism during this correction period.

Brief description of the figures

• La Figure 1 représente, en partie schématiquement, un premier mode de réalisation d'une pièce d'horlogerie selon l'invention munie d'un mouvement mécanique, d'un affichage de l'heure, d'un dispositif de détection pour l'affichage, et d'un dispositif de correction de l'heure affichée;
• La Figure 2 est une vue de dessus de la pièce d'horlogerie de la Figure 1;
• La Figure 3 est une coupe partielle de la pièce d'horlogerie des Figures 1 et 2, selon une première variante d'un premier mode de réalisation du dispositif de détection;
• Les Figures 4A à 4D sont des coupes schématiques de diverses variantes pour une source de lumière formant le dispositif de détection selon le premier mode de réalisation;
• Les Figures 5A et 5B sont des coupes schématiques partielles de deux variantes de configuration pour une aiguille dont il est prévu de détecter le passage au-dessus d'au moins un détecteur photosensible formant le dispositif de détection de la pièce d'horlogerie des Figures 1 et 2;
• La Figure 6 montre une pluralité de valeurs de mesure fournies par le dispositif de détection optique, selon le premier mode de réalisation, lors d'une phase de détection permettant de déterminer une erreur temporelle de l'aiguille des secondes et une erreur temporelle de l'aiguille des minutes;
• La Figure 7 représente schématiquement une variante du dispositif de correction de la pièce d'horlogerie selon le premier mode de réalisation;
• Les Figures 8 et 9 montrent, lors d'une correction opérée par une série d'impulsions de freinage périodiques, l'évolution de la fréquence d'oscillation d'un résonateur mécanique au cours d'une période de correction d'une avance, respectivement d'une période de correction d'un retard dans l'heure indiquée par un affichage de la pièce d'horlogerie considérée, et ceci pour le cas d'un rapport entre la fréquence de correction et la fréquence de consigne relativement proche de un;
• La Figure 10 montre, dans le cas d'un rapport relativement élevé entre la fréquence de correction et la fréquence de consigne, l'oscillation d'un résonateur mécanique au début d'une période de correction d'un retard par une série d'impulsions de freinage périodiques, cette période de correction présentant une phase transitoire initiale;
• La Figure 11 montre, lors d'une correction d'un retard opérée par une série d'impulsions de freinage périodiques, quelques périodes d'oscillation d'un résonateur mécanique au cours d'une phase synchrone pour deux fréquences de synchronisation différentes;
• La Figure 12A montre, pour une fréquence de freinage correspondant à une impulsion de freinage par alternance de l'oscillation d'un résonateur mécanique, plusieurs courbes de la fréquence de synchronisation relative maximale en fonction de l'amplitude de l'oscillation libre du résonateur et de son facteur de qualité;
• La Figure 12B montre, pour une fréquence de freinage qui correspond à une impulsion de freinage par période d'oscillation d'un résonateur mécanique, plusieurs courbes de la fréquence de synchronisation relative maximale en fonction de l'amplitude de l'oscillation libre du résonateur et de son facteur de qualité;
• La Figure 13A est un graphe donnant, pour une fréquence de consigne donnée, approximativement des plages de fréquence de correction possibles, pour corriger un retard dans l'affichage de l'heure à l'aide de courtes impulsions de freinage périodiques, en fonction de plusieurs fréquences de freinage sélectionnées pour les impulsions de freinage;
• La Figure 13B est un graphe donnant, pour une fréquence de consigne donnée, approximativement des plages de fréquence de correction possibles, pour corriger une avance dans l'affichage de l'heure à l'aide de courtes impulsions de freinage périodiques, en fonction de plusieurs fréquences de freinage sélectionnées pour les impulsions de freinage;
• La Figure 14 montre partiellement un deuxième mode de réalisation d'une pièce d'horlogerie selon l'invention;
• La Figure 15 montre partiellement un troisième mode de réalisation d'une pièce d'horlogerie selon l'invention;
• La Figure 16 représente schématiquement un quatrième mode de réalisation d'une pièce d'horlogerie selon l'invention;
• La Figure 17 représente schématiquement un cinquième mode de réalisation d'une pièce d'horlogerie selon l'invention;
• Les Figures 18 et 19 montrent l'oscillation du résonateur mécanique au cours d'une période de correction d'un retard respectivement pour deux variantes de réalisation du dispositif de freinage de la pièce d'horlogerie de la Figure 17;
• La Figure 20 est une première coupe partielle au travers d'une pièce d'horlogerie selon l'invention, laquelle comprend un deuxième mode de réalisation du dispositif de détection pour l'affichage, en relation avec une première unité de détection du passage de l'aiguille des secondes par une position temporelle de référence correspondante;
• La Figure 21 est une vue de dessus de la roue de secondes du mouvement mécanique formant la pièce d'horlogerie de la Figure 20;
• La Figure 22 est une deuxième coupe partielle au travers de la pièce d'horlogerie de la Figure 20, en relation avec une seconde unité de détection du passage de l'aiguille des minutes par une position temporelle de référence correspondante;
• La Figure 23 est une vue de dessus du mobile de minuterie du mouvement mécanique formant la pièce d'horlogerie de la Figure 22; et
• La Figure 24 est une vue de dessus de la seconde unité du dispositif de détection de la pièce d'horlogerie de la Figure 22.

The invention will be described below in more detail with the aid of the appended drawings, given by way of non-limiting examples, in which:

• The Figure 1 shows, in part schematically, a first embodiment of a timepiece according to the invention provided with a mechanical movement, a time display, a detection device for the display, and a device for correcting the displayed time;
• The Figure 2 is a top view of the timepiece from the Figure 1 ;
• The Figure 3 is a partial section of the timepiece of the Figures 1 and 2 , according to a first variant of a first embodiment of the detection device;
• The Figures 4A to 4D are schematic sections of various variants for a light source forming the detection device according to the first embodiment;
• The Figures 5A and 5B are partial schematic sections of two variant configurations for a hand of which it is intended to detect the passage above at least one photosensitive detector forming the device for detecting the timepiece. Figures 1 and 2 ;
• The Figure 6 shows a plurality of measurement values supplied by the optical detection device, according to the first embodiment, during a detection phase making it possible to determine a temporal error of the second hand and a temporal error of the second hand. minutes;
• The Figure 7 schematically shows a variant of the device for correcting the timepiece according to the first embodiment;
• The Figures 8 and 9 show, during a correction made by a series of periodic braking pulses, the evolution of the oscillation frequency of a mechanical resonator during a correction period 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 frequency of setpoint relatively close to one;
• The Figure 10 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 braking pulses periodic, this correction period having an initial transitional phase;
• The Figure 11 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;
• The Figure 12A 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;
• The Figure 12B shows, for a braking frequency which corresponds to a braking pulse per oscillation period 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;
• The Figure 13A is a graph giving, for a given reference frequency, approximately the possible correction frequency ranges, to correct a delay in the display of the time using short periodic braking pulses, as a function of several frequencies of braking selected for braking pulses;
• The Figure 13B 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, depending on several braking frequencies selected for the braking pulses;
• The Figure 14 partially shows a second embodiment of a timepiece according to the invention;
• The Figure 15 partially shows a third embodiment of a timepiece according to the invention;
• The Figure 16 schematically shows a fourth embodiment of a timepiece according to the invention;
• The Figure 17 schematically shows a fifth embodiment of a timepiece according to the invention;
• The Figures 18 and 19 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 the Figure 17 ;
• The Figure 20 is a first partial section through a timepiece according to the invention, which comprises a second embodiment of the detection device for the display, in connection with a first unit for detecting the passage of the hand of the seconds by a corresponding reference time position;
• The Figure 21 is a top view of the seconds wheel of the mechanical movement forming the timepiece of the Figure 20 ;
• The Figure 22 is a second partial cut through the timepiece of the Figure 20 , in connection with a second unit for detecting the passage of the minute hand through a corresponding reference time position;
• The Figure 23 is a top view of the timer mobile of the mechanical movement forming the timepiece of the Figure 22 ; and
• The Figure 24 is a top view of the second unit of the timepiece detection device of the Figure 22 .

Detailed description of the invention

With reference to Figures 1 to 7 , a first embodiment of a timepiece according to the invention will be described below, which incorporates a first embodiment of a detection device for the display.

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 real time indicated by the display. The timepiece is a wristwatch conventionally comprising a case 220 and a crown 52 forming an external control member to allow manual time setting of the display via an internal control rod integral with the crown. Generally, when setting the time manually via the stem-crown, the mechanical time correction system acts on a timer wheel in direct contact with a roadway carrying the minute hand and an hour wheel. bearing the hour hand. Thus, the hour and minute hands always retain a kinematic link even when setting the time. Only a shock can possibly cause an angular displacement of one of these two needles relative to the other, by a sliding of a needle on its axis. On the other hand, when setting the time via the stem-crown, the road undergoes friction relative to a mobile or a wheel of the drive mechanism and thus an angular displacement relative to the wheels of this drive mechanism located upstream, and therefore to the second wheel carrying the seconds hand. By construction of the usual mechanical movements, the seconds hand does not have a given phase relationship with the minute hand once a time setting has taken place via the stem-crown, that is, that is to say that there is in general no determined temporal / angular relationship between the indication of the current minute and the indication of the current second. When the indicator is precisely aligned with a minute scale (which generally also serves as a seconds scale when the hands of the minutes and seconds are coaxial), the seconds indicator has a temporal / angular position which is arbitrary (any position not determined). This fact relates in particular to timepieces fitted with a mechanical movement driving an analogue display of the time.

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 mechanical 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 34H giving the current time, a minute hand 34M giving the current minute, and a 34S seconds hand giving the current second of the displayed real time. The needles generally have different shapes, in particular different lengths and / or widths.

• une unité de commande 48 agencée pour pouvoir commander le dispositif de détection 30 de sorte que ce dispositif de détection effectue, durant une phase de détection, une pluralité de mesures successives et fournisse une pluralité de valeurs de mesure correspondantes,
• une unité de traitement 46 agencée pour pouvoir recevoir du dispositif de détection ladite pluralité de valeurs de mesure, via un signal de mesure S_Ms, et la traiter,
• une base de temps interne 42 comprenant un circuit d'horloge 44, cette base de temps interne générant un temps réel de référence TRf composé au moins d'une seconde courante de référence et d'une minute courante de référence.

The correction device 6 comprises a detection device 30 for the analog display 12, an electronic correction circuit 40, a communication unit 50 and a device 22, 22A for braking the mechanical resonator 14. The electronic correction circuit 40 comprises :

• a control unit 48 arranged to be able to control the detection device 30 so that this detection device performs, during a detection phase, a plurality of successive measurements and supplies a plurality of corresponding measurement values,
• a processing unit 46 arranged to be able to receive from the detection device said plurality of measurement values, via a measurement signal S _Ms , and process it,
• an internal time base 42 comprising a clock circuit 44, this internal time base generating a real time reference TRf composed of at least one current reference second and one current reference minute.

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 machined in the dial.

The timepiece 2 is arranged so as to allow a correction of the real time indicated by its display as a function of an overall time error for this display which is determined inside the timepiece by the circuit. electronic correction 40 associated with the detection device 30, which is arranged to be able to detect the passage of the seconds hand 34S by at least a first reference temporal position of the display and the passage of the minutes indicator 34M by at least one second reference time position of this display. To correct the displayed real 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 a control unit 48 which transmits to it a control signal S _Cmd 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 an overall time error has been determined by the electronic correction circuit, on the mechanical resonator during a correction period. to vary the operation of the drive mechanism so as to at least partially correct this overall time error.

In the variant shown, the actuator 22A comprises a braking member which is formed by a flexible blade 24, which is present on two opposite surfaces (perpendicular to the plane of the Figure 1 ) respectively two piezoelectric layers which are each coated with a metal 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 pad, 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, 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 the document WO 2018/177779 for various variant arrangements of such a braking device in a mechanical clockwork 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 first embodiment of the timepiece incorporates a first embodiment of the detection device, described below with reference to Figures 2 to 6 , which is distinguished by the fact that it allows direct detection of the passage of at least one indicator of the analog display 12, relating to a time unit of the real time, by at least one reference time position of this display which is relative to said time unit, this indicator being arranged to be able to be detected itself by the detection device. The description of the first embodiment of the timepiece 2 will be given essentially in the context of the main embodiment, in which the detection device is arranged to be able to detect the passage of the seconds indicator through at least a first one. reference time position of the display and the passage of the minute indicator through at least a second reference time position of this display, and in which the measurements for these two indicators are used in each correction cycle to perform a correction the current minute and the current second of the displayed real time.

In the advantageous variant shown in Figure 2 , the detection device 30 is of the optical type and comprises four detection units 224a, 224b, 224c and 224d which respectively define four reference time positions for the 34S seconds hands (15 s, 30 s, 45 s and 60 s = 0 s) and respectively four reference time positions for the 34M minute hands (15 min, 30 min, 45 min and 60 min = 0 min). It will be noted that in another variant, a single detection unit is provided or two diametrically opposed detection units are provided. It will also be noted that the variant shown advantageously provides the same detection units for detecting passages of the seconds hand and of the minute hand. However, in another variant, it is possible to provide different detection units for the two needles.

In general, the optical detection device comprises at least one light source, each capable of emitting a beam of light, and at least one photosensitive detector each capable of capturing light emitted by a light source of said at least one. light source. The seconds indicator and the minutes indicator each have a reflection surface which passes through the beam (s) of light emitted by at least one light source when the indicator in question passes through at least one time position reference corresponding to this indicator and defined by the detection device, in particular with regard to at least one detection unit of this detection device. The detection device and the reflection surface are configured in such a way that this reflection surface can reflect, during a passage of the indicator considered by any reference temporal position of said at least one corresponding reference temporal position, of incident light, supplied by a light source of said at least one light source, at least partially towards a photosensitive detector of said at least one photosensitive detector which is associated with said any reference time position. In a preferred variant, the reflection surface of each indicator considered is formed by a lower surface of this indicator, and said at least one light source and said at least one photosensitive detector are supported by a dial of the timepiece or housed at least partially in the dial, or located under the dial which is then arranged to allow the beam (s) of light to pass through it. In an advantageous variant, the light emitted by said at least one light source is not visible to the human eye. The light source notably emits light in the infrared range.

The Figure 3 is a partial cut of the watch from the Figure 2 , through the detection unit 224a of the optical detection device 30. It will be noted that the four detection units are similar. The watch case is represented by its internal profile 220a. The detection unit 224a comprises an optical sensor 226 formed by a light source 228, which emits a light beam 232, and a photosensitive detector 227 capable of picking up light emitted by the light source, the source and the detector. being aligned in a radial direction relative to the central axis of the watch around which the seconds hand and minute hand revolve. The optical sensor 226 is arranged under the dial 32 and supported by the plate of the mechanical movement 4. The dial has an opening in which is arranged a glass plate 230 which has at its lower surface a sawtooth profile forming two networks of refraction (series of parallel oblique planes) provided to respectively refract the light emitted by the source 228 and the light incident on the detector 227 after reflection by one or the other of the two hands 34M and 34S. The wafer may be made of another substance which exhibits sufficiently good transparency for the light emitted by the source 228, in particular for infrared light where appropriate. It will be noted that the plate can also form an upper element of the sensor 226 and then be inserted into the opening of the dial during the assembly of the optical sensor with the dial.

The optical detection unit 224a is remarkable because the electronic units forming the light source and the photosensitive detector are arranged on a common substrate in a general plane parallel to the dial 32 with the emitted light having a main direction (optical axis) which is. perpendicular to this general plane, but the light beam 232 is oblique. A layer of air between the wafer and the sensor 226 is an advantage for obtaining a fairly large angle of deflection of the light relative to the vertical direction, that is to say perpendicular to the dial. Thanks to such an arrangement, although the light emitted by the source 228 has a vertical optical axis, the reflecting areas RS1 and RS2 defined respectively by the two lower surfaces of the seconds hand 34S and the minute hand 34M are flat and horizontal. Thus, given that the lower surfaces of traditional hands are flat and parallel to the dial, the detection device requires little intervention on the hands, or even no intervention for metal hands or having a metallic coating. A polished surface in the RS1 and RS2 areas is an advantage. Note that the two needles 34M and 34S are shown, at the Figure 3 , one above the other to help understand the operation of the optical detection unit for each of the two needles; but the detection of the second hand is provided in the absence of the minute hand above the detection unit.

Since photosensitive detectors are often adapted to receive light having an oblique incidence (up to a certain angle of incidence), the problem associated with the desire for flat and horizontal reflecting surfaces for the needles relates firstly to the source of the light. light. To the Figures 4A to 4D four specific variants are shown for the light source of the optical detection units. In the first simple variant, the light source 228a, for example a diode of the LED type (acronym for 'Light-Emitting Diode') or a laser diode of the VCSEL type (acronym for 'Vertical-Cavity Surface-Emitting Laser'), is arranged obliquely on a support. This first variant has the disadvantage of considerably increasing the height of the device. In the second variant, one uses a property of conventional laser diodes of the VCSEL type, non-collimated, which naturally have a light intensity profile, shown on Figure 4B , with a maximum exhibiting an angular deviation relative to the perpendicular direction. Thus, the light beam 232, in a plane passing through its central axis, has two symmetrical main directions having an angular deviation ao. We will select a laser diode having a relatively large angular deviation. In the third variant, the light source 228c has at its emitting surface a diffraction structure RD which diffracts the light beam mainly in a given oblique direction. Finally, the fourth variant is similar to the variant of the Figure 3 . The light source 228d has on its emitting surface a transparent structure having its upper surface having a sawtooth profile which forms a refraction grating RD (series of parallel oblique planes) provided to refract the light emitted by the source 228d. While the planes inclined to the Figure 3 have an angle of about 45 °, the inclined planes of the refraction grating RD have a smaller angle relative to the direction horizontal (for example 35 °), so as to have a refraction angle for the light beam 232 which allows it to pass through the transparent structure.

Two variants, where a particular treatment of the lower surfaces of the needles concerned is accepted, are shown in Figures 5A and 5B . Note that these two variants can be complementary to the variants described above. To the Figure 5A , the needle 34D has a reflection diffraction grating in an area of its lower surface which passes through the incident beam 232a (beam having a normal direction) as it passes over an optical detection unit. To the Figure 5B , the needle 34R has a reflection grating in an area of its lower surface which passes through the incident beam 232a as it passes over an optical detection unit.

In general, the detection device comprises U detection units for the seconds indicator and Q detection units for the minutes indicator, some of these detection units possibly being common to both hands. In the variant shown, four detection units common to the two indicators are provided. The U detection units define U reference time positions X0 (u), u = 1 to U, for the seconds indicator, and the Q detection units define Q reference time positions Y0 (q), q = 1 to Q, for the minute indicator. Four detection units for the minute indicator allow this indicator to be detected within a time interval of approximately 15 minutes.

The detection device described above is of the optical type. However, it will be noted that the detection device can be of another type, in particular of the capacitive, magnetic or inductive type. A detection unit of the capacitive, magnetic or inductive type can be subjected to the same control as that described for an optical detection unit and the same processing of the measurements carried out can be provided within the framework of a correction cycle according to the present invention. ; which leads to the same correction of the actual time displayed.

With reference to the Figure 6 , we will now describe a detection phase, provided at the start of a cycle for correcting the displayed time, for the main embodiment in which the real reference time T _Rf generated by the internal time base 42 is composed at the less than one current second of reference X _R and one current minute of reference Y _R.

First, the electronic correction circuit 48, 48A is arranged and the duration of the detection phase is provided to allow the detection device to detect during this detection phase, while the drive mechanism 10 ( Figure 1 ) is running and clocked by the oscillating mechanical resonator 14, at least one passage of the seconds indicator 34S through a reference time position among the reference time positions X0 (u), u = 1 to U, and at least a passage of the minute indicator through a reference time position among the reference time positions Y0 (q), q = 1 to Q. The electronic correction circuit is arranged to be able to determine, in association with the internal time base 42 and on the basis of measurement values of a plurality of measurement values, at least a first time of passage T _X0 of the seconds indicator through any reference time position, called X0, among the reference time positions provided for this seconds indicator, this first passing instant being made up of at least one corresponding value of the current reference second X _R , and at least one second passing instant T _Y0 of the minutes indicator by any second reference time position, called Y0, from among the reference time positions provided for this minute indicator, this second passing instant being made up of at least one corresponding value of the current reference minute Y _R. In the following explanations, it is therefore considered that the seconds hand is detected by a detection unit corresponding to the reference time position X0, and the minute hand is detected by a detection unit corresponding to the time position of reference Y0.

To detect the passage of an indicator through a reference time position, a plurality of measurements are carried out at a measurement frequency F _Ms. Each measurement gives a measurement value and takes place at a determined measurement instant. To do this, measurements are taken over short time intervals. In the case of an optical detection unit of an optical detection device, the light source is periodically activated at the measurement frequency F _Ms to generate a plurality of light pulses, and the photosensitive detector supplies a plurality of values. corresponding luminous intensity.

In a first general variant, during the detection phase, the detection device is activated so as to perform a plurality of successive measurements at at least one measurement frequency which is determined by the clock circuit 44 of the time base. internal 42, this clock circuit supplying a periodic digital signal at the measurement frequency F _Ms directly to the detection device or indirectly to this detection device via the control unit. In a preferred variant, the measurement frequency is variable and the correction device 6 is arranged to be able to detect the passage of the seconds indicator through the reference time position X0 with a first measurement frequency FS _Mes and the passage of l. 'minute indicator by the reference time position Y0 with a second measurement frequency FM _Mes which is lower than the first measurement frequency. In a particular variant, the first measurement frequency FS _Mes is provided less than three times a setpoint frequency F0c for the mechanical resonator 14 and greater than or equal to 1 Hz, _{i.e. 1 Hz <= FS Mes} <3 · F0c, whereas the second FM _Mes measurement frequency is expected to be less than or equal to 1/8 Hz (FM _Mes <= 1/8 Hz).

It may be advantageous, so that the detection units can perform measurements correctly and to slightly increase the precision of determining the instants of passage of the two hands through their respective reference time positions, that the seconds hand or noticeably still during the measurements. If, for example, a mechanical resonator oscillating at approximately 4 Hz is taken and the measuring frequency for the seconds hand corresponds to 4 Hz or 8 Hz, all the measurements may take place during the sustaining pulses of the mechanical resonator. and therefore when the escape wheel turns and also the second wheel carrying the seconds hand. To prevent the majority of the measurements from taking place when the seconds hand undergoes a small rotational movement, provision is made, in an advantageous variant, for the first measurement frequency FS _{Mes to} have a value other than double the reference frequency F0c divided by a positive whole number N, that is FS _Mes ≠ 2 · F0c / N.

In another more advanced variant, the measurement frequency is determined by the mechanical resonator in association with the clock circuit. The device for correcting the displayed real time then comprises a sensor associated with the mechanical resonator and arranged to be able to detect the passages of the oscillating resonator through its neutral position, corresponding to its position of minimum potential energy. During the detection phase, the detection device is activated and controlled by the control unit associated with the internal time base to perform a plurality of successive measurements each following the detection of a passage of the mechanical resonator by its position. neutral and after a certain time phase shift since this detection. Preferably, this time phase shift is between T0c / 8 and 3 · T0c / 8, where T0c is the reference period which is equal to the inverse of the reference frequency. To do this, the clock circuit 44 is arranged to supply the control unit with a periodic signal at a frequency equal to 8 / T0c or close to this value. The sensor provides the control unit with a signal indicating when the mechanical resonator passes through its neutral position. Following this instant, the control unit activates the reception of the signal supplied by the clock circuit at the frequency approximately equal to 8 / T0c and counts two rising or falling edges in the periodic signal. At the second considered flank, the control unit triggers a measure and therefore a light pulse. If desired, we can therefore know the instant of each measurement. Since the clock circuit and the mechanical resonator are not synchronized, the time phase shift will be within the above-mentioned range of values. With a phase shift in this range, the anchor wheel is stationary and the seconds hand is thus stationary during measurements. In this advanced variant, the measurement frequency is equal to 2 · F0c if a measurement is carried out on each detection of a passage of the resonator through its neutral position. If a measurement is carried out every N detections, the measurement frequency is approximately equal to 2 · F0c / N. It will be noted that for the processing of the measurements which will be described below, it can be assumed that the natural frequency F0 of the resonator is equal to F0c, so that F _Ms = 2 · F0c / N. If a watch has a large daily error, for example 14 seconds per day, this corresponds to an error of 10 ms for one minute. Since one minute is a sufficient detection period for the second hand, such an error is insignificant in calculating a time error for that hand.

To the Figure 6 is shown a first series of measurements carried out for the detection of the seconds hand at a first frequency FS _Ms = 4 Hz, preferably using the advanced variant described above if the setpoint frequency for the mechanical resonator is also equal at 4 Hz, and a second series of measurements at a second FM frequency _Ms = 1/10 Hz (every 10 seconds to save energy) since the minute hand turns 60 times slower than the hand seconds and generally has a greater width. Note that 4 Hz can easily be derived from clock circuit 44 which is arranged to provide second ticks at the time base for the measurement of the real time reference. The FM frequency _Ms is generated by a cyclic counter of ten, incremented by the second ticks associated with the control unit.

The first series of measurements gives a first series of intensity values VS _n , n being a positive integer, to which a first series of measurement instants TS _n corresponds. The second series of measurements gives a second series of intensity values VM _k , k being a positive integer, to which a second series of measurement instants TM _k corresponds. Thus, to each measurement corresponds a pair of values VS _n and TS _n , respectively VM _k and TM _k.

$${\mathrm{TM}}_{\mathrm{k}}=\left(\mathrm{k}-\mathrm{Y}\right)/{\mathrm{FM}}_{\mathrm{Ms}}+{\mathrm{TM}}_{\mathrm{Rf},\mathrm{Y}}$$

For the processing phase which follows the detection phase, it is not planned to record the real reference time corresponding to each measurement during the detection phase, but it is planned to number or classify in chronological order the measurements of each series of measurements, and to establish a temporal link with the real reference time T _Rf for each series of measurements. In the case of a numbering which associates a number n, respectively k with each value VS _n , respectively VM _k , the periodic digital signal at the measurement frequency F _Ms (periodic measurement signal) can also be supplied to the unit processing 46 which receives the measurement values via a signal S _Ms supplied to it by the detection device, directly or via the control unit. In the case of a classification in chronological order, the rank of the measurement value may be sufficient to determine the corresponding measurement instant. It is known that two successive measurements of the same series are separated by a period T _Ms which is the inverse of the measurement frequency F _Ms. If for an instant X, respectively Y given by the periodic measurement signal, the control unit or directly the processing unit stores the corresponding real reference time TS _{Rf, X} for the seconds hand, respectively TM _{Rf, Y} for the minute hand, and if a number of periods of the periodic measurement signal is determined between the stored reference real time and a measurement of rank n, respectively of rank k, then the rank (or number) of each measurement corresponds to a determined real reference time. This temporal relation can be expressed mathematically as follows: $${\mathrm{TS}}_{\mathrm{not}}=\left(\mathrm{not}-\mathrm{X}\right)/{\mathrm{FS}}_{\mathrm{Ms}}+{\mathrm{TS}}_{\mathrm{Rf},\mathrm{X}}$$

$${\mathrm{TM}}_{\mathrm{k}}=\left(\mathrm{k}-\mathrm{Y}\right)/{\mathrm{FM}}_{\mathrm{Ms}}+{\mathrm{TM}}_{\mathrm{Rf},\mathrm{Y}}$$

avec n = 1 à N $${\mathrm{TM}}_{\mathrm{k}}=\mathrm{k}/{\mathrm{FM}}_{\mathrm{Ms}}+{\mathrm{TM}}_{\mathrm{Rf},\mathrm{0}}$$

avec k = 1 à K
où N et K sont les nombres de mesures pour respectivement la détection de l'aiguille des secondes et de l'aiguille des minutes.A particular case concerns X = Y = 0. The control unit waits for a second signal which defines an initial time for a series of measurements and as soon as it receives it, on the one hand it activates the detection device or it takes in consideration of the measurements occurring only from this initial instant, with the exception of this initial instant, and on the other hand it records the real reference time TS _{Rf, X} , respectively TM _{Rf, 0} . Thus, we have: $${\mathrm{TS}}_{\mathrm{not}}=\mathrm{not}/{\mathrm{FS}}_{\mathrm{Ms}}+{\mathrm{TS}}_{\mathrm{Rf},\mathrm{0}}$$

with n = 1 to N $${\mathrm{TM}}_{\mathrm{k}}=\mathrm{k}/{\mathrm{FM}}_{\mathrm{Ms}}+{\mathrm{TM}}_{\mathrm{Rf},\mathrm{0}}$$

with k = 1 to K
where N and K are the numbers of measurements for the detection of the second hand and the minute hand, respectively.

A la Figure 6, T_X0 = 10 s et 250 ms (T_X0 = 10,25 s).The processing unit 46 performs a processing of each series of measurements to determine the first moment of passage T _X0 of the seconds indicator through the reference time position X0 and the second moment of passage T _Y0 of the minutes indicator by the reference time position Y0. Various methods of processing measurement data can be used. As examples, we can cite the two examples in connection with the Figure 6 , and a simplified example. To determine the value T _X0 , given that the seconds hand is relatively thin and rotates relatively quickly, an algorithm determines the maximum value VS _max to which corresponds a rank / number n = Z _E.
So $${\mathbf{<figure-callout\; id="0"\; label="T\; X"\; filenames="imgf0006.png,imgf0007.png"\; state="\{\{state\}\}">T</figure-callout>}}_{\mathbf{X}}={\mathrm{Z}}_{\mathrm{E}}/{\mathrm{FS}}_{\mathrm{Ms}}+{\mathrm{TS}}_{\mathrm{Rf},\mathrm{0}}$$

To the Figure 6 , T _X0 = 10 s and 250 ms (T _X0 = 10.25 s).

To determine the value T _Y0 , an algorithm determines a width, corresponding to a time interval IT, approximately at mid-height of a symmetrical convex curve C _Fit adjusted to the series of measurement values VM _{k in order} to be able to determine a middle value of this width, this middle value defining the moment of passage T _Y0 of the middle longitudinal axis of the minute hand by the reference temporal position Y0, which is defined by the radial middle axis of the detection unit concerned / by the direction of radial alignment of the light source and the photosensitive detector. It will be noted that the time interval IT is a characteristic parameter of the indicator concerned which makes it possible to differentiate it from the other indicators. In addition, the maximum light intensity detected is also a characteristic parameter of the indicator considered. For the processing of the data, the algorithm implemented in the processing unit advantageously uses the numbers / ranks k corresponding to the values VM _k . It is observed here that the value T _Y0 does not correspond to a whole row / number (the measurements intervening here only every 10 seconds), but it corresponds to a fractional number Z _F intermediate between two adjacent rows / numbers.
So $${\mathbf{<figure-callout\; id="0"\; label="T\; Y"\; filenames="imgf0006.png,imgf0007.png"\; state="\{\{state\}\}">T</figure-callout>}}_{\mathbf{Y}}={\mathrm{Z}}_{\mathrm{F}}/{\mathrm{FM}}_{\mathrm{Ms}}+{\mathrm{TM}}_{\mathrm{Rf},\mathrm{0}}$$

To the Figure 6 , T _Y0 = 17 minutes and 48 seconds (T _Y0 = 17 min; 48 s). T _Y0 therefore has an integer value PM _Y0 in minutes (integer part of T _Y0 ) corresponding to the current reference minute when the indicator passes through the reference time position Y0, to which is added a value PS _Y0 in seconds which defines a fractional part for the current minute given by the minute indicator when the indicator passes through the reference time position Y0, this value PS _Y0 corresponding to the current reference second when the indicator passes minutes by the reference time position Y0. We will thus denote by T _Y0 = (PM _Y0 ; PS _Y0 ). It will be noted that the value PS _Y0 can possibly have decimals. We can in a simplified variant ignored PS _Y0 , but then we lose a lot of precision for the minute hand. Thus, in the main embodiment, the instant at which the minute hand passes through a reference time position (which generally corresponds to an integer number of minutes) is generally determined with an integer part in minutes and a part fractional in seconds (part sexagesimal), this determination preferably being carried out with a precision of the order of a second or less than a second.

In the two processing methods described above, in general, the control unit and / or the processing unit is / are connected to the internal time base so as to be able to store the time. reference real at least at a given instant of the detection phase. The electronic correction circuit is designed to be able to determine, during the detection phase, at least a first measurement instant and a second measurement instant corresponding respectively to at least a first measurement and a second measurement from among a series of successive measurements, these first and second measurement instants being determined by the internal time base. The first measurement instant is made up of at least one corresponding first value of the current reference time unit and the second measurement time is made up of at least one second value of this current reference time unit. Then, the electronic correction circuit is arranged to be able to calculate, as a function of said at least a first measurement moment and a second measurement moment and the corresponding measurement values, a third moment which determines the moment of passage of the indicator. considered by the reference temporal position concerned.

In a simplified variant, the instant of passage of a hand through a reference temporal position is determined by comparing each measurement value received by the processing unit directly with a threshold value provided for this hand. As soon as the processing unit detects that the value of a measurement exceeds this threshold value, it assigns the instant of this measurement to the instant of passage and it records the real time reference value directly following this detection. . This simplified variant is less precise, but it requires few electronic resources. The electronic correction circuit can therefore be simplified.

Following the determination of the passing instants described above, the electronic correction circuit is arranged to be able to determine a first temporal error for the seconds indicator, by comparing at least a first passing instant of this seconds indicator with a first corresponding reference time position, and a second time error for the minutes indicator by comparing at least a second time of passage of this minute indicator with a second corresponding reference time position. In a general variant, the determination of the first temporal error and of the second temporal error is carried out by the processing unit which performs a subtraction between the determined passage instant and the value of the corresponding reference temporal position.

$${\mathbf{E}}_{\mathbf{M}}={\mathrm{T}}_{\mathrm{Y}\mathrm{0}}-\mathrm{Y}\mathrm{0}$$

For the seconds indicator and the minute indicator, the two respective time errors E _S and E _M are given by: $${\mathbf{E}}_{\mathbf{s}}={\mathrm{T}}_{\mathrm{X}\mathrm{0}}-\mathrm{<figure-callout\; id="0"\; label="X"\; filenames="imgf0006.png,imgf0007.png"\; state="\{\{state\}\}">X</figure-callout>}\mathrm{0};$$

$${\mathbf{E}}_{\mathbf{M}}={\mathrm{T}}_{\mathrm{Y}\mathrm{0}}-\mathrm{<figure-callout\; id="0"\; label="Y"\; filenames="imgf0006.png,imgf0007.png"\; state="\{\{state\}\}">Y</figure-callout>}\mathrm{0}$$

By construction, X0 corresponds to an integer number of seconds and Y0 corresponds to an integer number of minutes, that is Y0 = (Y0; 0). E _S is given in seconds, possibly with one or more decimal places since T _X0 is normally determined with decimals (precision better than the second). The processing algorithm can decide to keep for example only one decimal place. As the passing instant T _Y0 determined for the minutes indicator has an integer part PM _Y0 in minutes and a fractional part PS _Y0 in seconds, the time error E _M is determined with an integer part E _Mm in minutes and a fractional part E _Ms in seconds (E _{Ms is} therefore added to E _Mm ). According to the chosen notation: E _M = (E _Mm ; E _Ms ) . It will be noted that E _Ms can have one or more decimal places resulting from the calculation carried out for its determination, but the algorithm does not generally keep a decimal for the value E _Ms in seconds given that this value is already one for the minutes indicator. fractional part.

We formally note: $${\mathbf{E}}_{\mathbf{M}}=\left({\mathrm{E}}_{\mathrm{Mm}};{\mathrm{E}}_{\mathrm{Ms}}\right)=\left({\mathrm{<figure-callout\; id="0"\; label="PM\; Y"\; filenames="imgf0006.png,imgf0007.png"\; state="\{\{state\}\}">PM</figure-callout>}}_{\mathrm{Y}};{\mathrm{PS}}_{\mathrm{Y}\mathrm{0}}\right)-\left(\mathrm{<figure-callout\; id="0"\; label="Y"\; filenames="imgf0006.png,imgf0007.png"\; state="\{\{state\}\}">Y</figure-callout>}\mathrm{0};\mathrm{0}\right)=\left({\mathbf{PM}}_{\mathbf{Y}\mathbf{0}}-\mathbf{<figure-callout\; id="0"\; label="Y"\; filenames="imgf0006.png,imgf0007.png"\; state="\{\{state\}\}">Y</figure-callout>}\mathbf{0};{\mathbf{<figure-callout\; id="0"\; label="PS\; Y"\; filenames="imgf0006.png,imgf0007.png"\; state="\{\{state\}\}">PS</figure-callout>}}_{\mathbf{Y}}\right)\mathrm{.}$$

• X0 = 15 s et E_S = 10,25 - 15 = -4,75 s
• Y0 = (15 ; 0) et E_M = (17 ; 48) - (15 ; 0) = (2 ; 48), soit 2 min et 48s.

In the example of Figure 6 :

• X0 = 15 s and E _S = 10.25 - 15 = -4.75 s
• Y0 = (15; 0) and E _M = (17; 48) - (15; 0) = (2; 48), i.e. 2 min and 48s.

1. 1) Un affichage de l'heure réelle est formé de plusieurs indicateurs distincts qui sont utilisés pour représenter l'écoulement du temps. Ils sont donc tous relatifs à une seule et même grandeur physique, le temps.
2. 2) Les mouvements mécaniques horlogers traditionnels comprennent un dispositif de mise à l'heure manuel qui rompt momentanément le lien cinématique entre, d'une part, l'indicateur des secondes et, d'autre part, l'indicateur des minutes et l'indicateur des heures. Ainsi, un déphasage temporel quelconque, entre zéro et soixante secondes, apparait normalement entre la partie fractionnaire de la minute courante affichée par l'indicateur des minutes et la seconde courante affichée par l'indicateur des secondes. Par conséquence, la minute courante affichée présente, de manière visible en présence d'une graduation des minutes et secondes, une partie fractionnaire en secondes dont la valeur diffère de la partie entière de la seconde courante affichée, laquelle est aussi en secondes. On a donc une différence en secondes entre deux données affichées qui sont tous deux relatives à la seconde.

It is observed that the fractional part E _Ms of the time error E _M relating to the current minute displayed by the minutes indicator is quite different from the time error E _S of the current second displayed by the seconds indicator. As explained above, this situation is not abnormal for a conventional mechanical movement given that the kinematic link between these two indicators is broken during a manual setting of the display by a user. Thus, a specific problem is brought to light, which usually arises from the following two facts:

1. 1) An actual time display is made up of several separate indicators which are used to represent the flow of time. They are therefore all relative to one and the same physical quantity, time.
2. 2) Traditional mechanical watch movements include a manual time-setting device which momentarily breaks the kinematic link between, on the one hand, the seconds indicator and, on the other hand, the minutes indicator and the hour indicator. Thus, any time phase shift, between zero and sixty seconds, normally appears between the fractional part of the current minute displayed by the minutes indicator and the current second displayed by the seconds indicator. Consequently, the current minute displayed has, visibly in the presence of a graduation of minutes and seconds, a fractional part in seconds whose value differs from the whole part. of the current second displayed, which is also in seconds. There is therefore a difference in seconds between two data displayed which are both relative to the second.

In the context of the present invention, provision has been made for the electronic correction circuit to be able to further determine an overall time error T _Err , for the display of a mechanical type watch, as a function of the first time error determined for the indicator for seconds, the second time error determined for the minute indicator, and at least one predefined correction criterion that selects a way to handle the first and second time errors to determine an overall time error for the timepiece display.

• Critère No 1 : Après correction, l'indicateur des secondes doit indiquer correctement la seconde courante, c'est-à-dire au mieux.
• Critère No 2 : Après correction, l'erreur résiduelle en secondes pour l'indicateur des minutes doit être supérieure ou égale à un retard maximum sélectionné T_max, soit supérieure ou égale à -T_max

In a preferred processing mode for the main embodiment, in a main variant where the minute indicator is of the analog type, two correction criteria are established, namely:

• Criterion No 1: After correction, the seconds indicator must correctly indicate the current second, that is to say at best.
• Criterion No 2: After correction, the residual error in seconds for the minutes indicator must be greater than or equal to a selected maximum delay T _max , i.e. greater than or equal to -T _max

Thus, in a main variant, provision is made for at least the minute indicator, among the set of indicators, to be of the analog type, this minutes indicator displaying a positive whole number of minutes and a fractional part which is variable. Next, the timepiece further comprises a time-setting device which is arranged so as to momentarily break the kinematic connection between the minutes indicator and the seconds indicator in order to set the time to said time. display. Finally, the electronic correction circuit is arranged to be able to determine an overall time error (T _Err ) for the display as a function of at least one predefined correction criterion for the seconds indicator and / or the minutes indicator in no more first and second errors times relating to the seconds and minutes indicators respectively.

In a preferred variant, the overall time error is determined so as to substantially correct the first time error for the seconds indicator during said correction period.

In an advantageous variant, the overall time error is determined so that the minutes indicator is present at the end of the correction period, for the case where this minutes indicator then has a time phase shift corresponding to a delay, at most a maximum delay which is selected in the range of values of the fractional part of the current minute displayed, that is to say between zero and sixty seconds of delay.

• On calcule une erreur cumulée EC_Ms, relative à la partie fractionnaire en secondes de la minute courante affichée par l'indicateur des minutes, en appliquant théoriquement le premier critère de correction, à savoir en soustrayant l'erreur temporelle E_S de l'indicateur des secondes de la partie fractionnaire E_Ms de l'erreur temporelle E_M de l'indicateur des minutes, soit : EC_Ms = E_Ms - E_S
• On effectue la division entière de l'erreur cumulée EC_Ms par soixante (cette opération est notée 'EC_Ms modulo 60') ; ce qui donne un quotient Q_M (nombre entier de minutes) et un reste R_S en secondes (positif).
• On sélectionne un retard maximum T_max pour l'indicateur des minutes, selon le deuxième critère de correction.
• On détermine une erreur globale E_MG pour la valeur relative à la minute dans l'erreur temporelle globale T_Err, cette erreur globale E_MG pouvant prendre deux valeurs différentes en fonction du reste R_S de ladite division entière et dudit retard maximum T_max, soit : $${\mathbf{E}}_{\mathbf{MG}}={\mathbf{E}}_{\mathbf{Mm}}+{\mathbf{Q}}_{\mathbf{M}}$$
  
  si Rs appartient à la plage [0 ; 59 - T_max] $${\mathbf{E}}_{\mathbf{MG}}={\mathbf{E}}_{\mathbf{Mm}}+{\mathbf{Q}}_{\mathbf{M}}+\mathbf{1}$$
  
  si Rs appartient à la plage [60 - T_max ; 59] pour le cas où T_max est supérieur à zéro.
• On définit l'erreur temporelle globale à corriger : T_Err = (E_MG ; E_s) où E_MG est un nombre entier de minutes, et Es est formé d'un nombre entier de secondes avec éventuellement une ou plusieurs décimale(s).

In a preferred variant, the processing algorithm implemented in the processing unit 46 to determine the overall time error T _Err is as follows:

• We calculate a cumulative error EC _Ms , relating to the fractional part in seconds of the current minute displayed by the minute indicator, by theoretically applying the first correction criterion, namely by subtracting the time error E _S from the indicator seconds of the fractional part E _Ms of the time error E _M of the minute indicator, _i.e. EC Ms = E _Ms - E _S
• The cumulative error EC _{Ms is} divided integer by sixty (this operation is denoted 'EC _Ms modulo 60'); which gives a quotient Q _M (whole number of minutes) and a remainder R _S in seconds (positive).
• A maximum delay T _max is selected for the minutes indicator, according to the second correction criterion.
• A global error E _{MG is determined} for the value relating to the minute in the global time error T _Err , this global error E _{MG being} able to take two different values as a function of the remainder R _S of said integer division and of said maximum delay T _max , is : $${\mathbf{E}}_{\mathbf{MG}}={\mathbf{E}}_{\mathbf{Mm}}+{\mathbf{Q}}_{\mathbf{M}}$$
  
  if Rs belongs to the range [0; 59 - T _max ] $${\mathbf{E}}_{\mathbf{MG}}={\mathbf{E}}_{\mathbf{Mm}}+{\mathbf{Q}}_{\mathbf{M}}+\mathbf{1}$$
  
  if Rs belongs to the range [60 - T _max ; 59] for the case where T _max is greater than zero.
• We define the global temporal error to be corrected: T _Err = (E _MG ; E _s ) where E _MG is an integer number of minutes, and Es is formed by an integer number of seconds with possibly one or more decimal (s) .

Thus, in the example of Figure 6 , by selecting T _max = 15 s:
E _S = -4.75 s, E _M = (2 min; 48 s); EC _Ms = 48 + 4.75 = 52.75 s EC _Ms modulo 60 gives: Q _M = 0; R _S = 53 s (rounded value) E _MG = E _Mm + Q _M + 1 = 2 + 0 + 1 = 3; T _Err = (E _MG ; E _s ) = (3; -4.75).

It will be noted that the variant T _max = 0 corresponds to a particular case where it has been decided that the minute hand must not show a delay, but must always be corrected to be exactly at the current reference minute or to present a certain advance. between '0' and '59' seconds. A selection of T _max = 30 s corresponds to a case where the minute hand has a residual error after correction between a delay of 30 seconds (-30 s) and an advance of 30 seconds (+30 s). A variant with T _max = 15 s may prove to be advantageous, a good compromise.

• Exemple 1
  E_S = 25 s, E_M = (-2 min ; 19 s) ; EC_Ms = 19 - 25 = - 6 s
  EC_Ms modulo 60 donne : Q_M = -1 min ; R_S = 54 s
  E_MG = E_Mm + Q_M + 1 = -2 - 1 + 1 = -2 ; T_Err = (-2 ; 25) = (-1 ; -35)
• Exemple 2
  E_S = - 30 s , E_M = (-2 min ; 36 s) ; EC_Ms = 36 + 30 = 66 s
  EC_Ms modulo 60 donne : Q_M = 1 ; R_S = 6 s
  E_MG = E_Mm + Q_M = -2 + 1 = -1 ; T_Err = (-1 ; -30)
• Exemple 3
  E_S = 5 s, E_M = (1 min ; 42 s) ; EC_Ms = 42 - 5 = 37 s
  EC_Ms modulo 60 donne : Q_M = 0 ; R_S = 37 s
  E_MG = E_Mm + Q_M = 1 + 0 = 1 ; T_Err = (1 ; 5)

As a complement, here are three examples (with T _max = 15 s):

• Example 1
  E _S = 25 s, E _M = (-2 min; 19 s); EC _Ms = 19 - 25 = - 6 s
  EC _Ms modulo 60 gives: Q _M = -1 min; R _S = 54 s
  E _MG = E _Mm + Q _M + 1 = -2 - 1 + 1 = -2; T _Err = (-2; 25) = (-1; -35)
• Example 2
  E _S = - 30 s, E _M = (-2 min; 36 s); EC _Ms = 36 + 30 = 66 s
  EC _Ms modulo 60 gives: Q _M = 1; R _S = 6 s
  E _MG = E _Mm + Q _M = -2 + 1 = -1; T _Err = (-1; -30)
• Example 3
  E _S = 5 s, E _M = (1 min; 42 s); EC _Ms = 42 - 5 = 37 s
  EC _Ms modulo 60 gives: Q _M = 0; R _S = 37 s
  E _MG = E _Mm + Q _M = 1 + 0 = 1; T _Err = (1; 5)

The determination of the overall time error T _Err is carried out by the processing unit which then supplies it to the control unit for the phase of correcting the time displayed by the timepiece. However, the overall time error can also be calculated by the control unit which then receives from the processing unit the time errors determined for the indicators considered. Thus the correction signal S _Cor supplied by the processing unit comprises either the value T _Err or the values E _S and E _M. It will be noted that the processing unit and the control unit can advantageously be formed by a single electronic circuit or a single electronic unit. The distinction between these two units is functional, to better expose the various phases of a correction cycle.

The global correction of the display of the watch to be carried out during a correction cycle is given by -T _Err fully converted into seconds. Thus, in Example 1 we will correct by performing an advance of 95 seconds, in Example 2 we will correct by performing an advance of 90 seconds, and in Example 3 we will correct by performing a retreat of 65 seconds in the actual time displayed.

It will be noted that the embodiments described relate to a correction device intended to correct the actual time displayed as a function of two temporal errors determined respectively for a seconds hand and a minute hand of a watch provided with a mechanical movement, but the invention is not limited to this main embodiment. Indeed, in a particular embodiment, a temporal error is also determined for the hour hand and the correction provided is also a function of this temporal error. For the needle hours which is normally in phase with the minute hand and continuously in meshing relation with this minute hand, only the difference between the current time displayed and a current reference time given by the time base is taken into account. account to determine the overall timing error.

In another particular embodiment, the timepiece only comprises an indicator of the current hour and an indicator of the current minute (therefore no indication of the current second). In a preferred variant, only one temporal error is then determined for the minute indicator. In this variant, the overall time error is equal to the time error determined for the minute indicator. It will be noted that in an embodiment where the timepiece also has a seconds hand, one could ignore, in a variant, the indication of the seconds and only precisely correct the minute hand. However, although such a variant makes it possible to give the real time with a correct indication of the current minute, it makes little sense because the seconds hand then gives an erroneous indication and its presence seems unnecessary.

In a simple variant, only the seconds hand is detected and only its possible temporal error is therefore corrected. For this last variant to have a meaning, we must admit that the minute hand correctly indicates the current minute. This is a possible case if a correction cycle is provided with a sufficiently high frequency, for example once a day or once every two days. However, in the preferred variants, the minutes indicator is detected and its possible time error is taken into account for the correction of the actual time displayed, because the error to be corrected does not depend only on the time drift, but also possible manipulations of the stem-crown pulled into its time-setting position or various possible disturbances.

Finally, the timepiece further comprises a communication unit 50 which is arranged to receive from an external device, an external installation or an external system a synchronization signal S _Sync providing an exact real time or an external system. exact real time which is composed only of the exact current minute and the exact current second, since in the main embodiment only the second and minute indicators are detected and then corrected globally. When it receives an S _Sync signal, the communication unit 50 supplies the exact real time H _RE or said exact real time to the internal time base 42 which then synchronizes the real reference time / the real reference time. on the exact real time / this exact real time. The external synchronization system can be a GPS system which gives a very precise legal time. In this case, the communication unit is formed by a unit for receiving a GPS signal relating to the exact real time. In another variant, the outdoor installation is a long-distance radio-synchronization antenna, such as is found in particular in Europe and the USA. In this case, the communication unit is formed by a unit for receiving an RF signal. In another variant, which may be complementary to one of the two abovementioned variants, the external device is a portable electronic device, for example a portable telephone or a computer. In this case, the communication unit comprises a BLE (acronym for 'Bluetooth Low Energy') or NFC (acronym for 'Near Field Communication') communication unit. It will be noted that in the last variant, the exact real time or the exact real time is generally derived from the time base of the external device, which is normally regularly synchronized on a clock giving the exact legal time via the telephone network or via the Internet network.

In general, the correction device comprises a wireless communication unit which is arranged to be able to communicate with an external system capable of providing the exact real time, the correction device being arranged to be able to synchronize the real reference time. on an exact real time, composed of current time units of the exact real time corresponding to those of the reference real time, during a synchronization phase during which the communication unit is activated so as to receive external system the exact real time or said exact real time.

In an advantageous variant, the communication unit is activated periodically by the control unit or directly by the internal time base in order to receive the exact real time or the exact real time. Thus, the communication unit is activated periodically and automatically, in order to synchronize the reference real time with the exact real time during a synchronization phase. In a preferred variant, provision is made for the user to be able to activate the communication unit, in particular via an external control member of the timepiece. The two variants can be combined to have automatic periodic synchronization and the possibility of performing synchronization on demand.

The communication unit is particularly important following a cut in the power supply to the internal time base. Thus, the control unit is arranged so as not to perform any correction cycle if the reference real time has not been synchronized on an external system providing the exact real time and maintained by the internal clock circuit. uninterrupted since a last synchronization phase. In a preferred variant, as soon as the time base is deactivated for one reason or another, this information is recorded in a permanent memory (non-volatile memory) which includes at least one status bit ('ON' / 'OFF' ) for the internal time base. On subsequent activation of the time base again, the status bit keeps its value 'OFF' until the correction device synchronizes the time base to the exact real time of an external system, such as exposed. Before performing a correction cycle, in particular before performing a phase detection, the control unit interrogates the status bit to find out its value, and does not perform any detection phase as long as this value is 'OFF'. Only when the value of the status bit is 'ON', the correction device then starts a new correction cycle with a detection phase. If a cycle is interrupted and it is planned to continue it, in particular following a possible interruption of a correction cycle between the treatment phase and the correction phase, the control unit can subsequently continue such a cycle. correction provided that the previous detection phase has been completed correctly and that the real reference time is no longer useful for the continuation of the correction cycle.

In an advantageous embodiment, the timepiece comprises an external control member for synchronizing the real reference time with the exact real time, this external control member being operable by a user of the timepiece. The external controller and the correction device are arranged so as to allow a user to activate the correction device so that this correction device performs a synchronization of the reference real time to the exact real time during a synchronization phase. In a particular variant, the external control member is formed by a crown associated with a control rod which also serve to set the time of the display manually.

Another problem must be considered in connection with a watch having a mechanical movement. As already explained, such a watch conventionally comprises a manual time-setting device via a stem-crown. Thus, it is necessary to avoid that a correction cycle by the correction device according to the invention is disturbed by a manual time setting (with the exception of a manual control provided to make the hour hand jump. by one hour jump, manual control which is moreover advantageous for the timepiece according to the invention, in particular for the main embodiment described above). We can provide a mechanism to block the external control organ (the stem-crown) so that it cannot modify the position of the minute hand and / or stop the seconds hand during a correction cycle. This normally requires an electromechanical actuator, which makes the timepiece more complex. An alternative is to arrange for the movement of the stem-crown to be detected, in particular to detect whether this control member is moved to a position corresponding to the time setting with the possibility of modifying the position of the minute hand. and / or the seconds hand. As soon as such detection occurs, the control unit ends the current correction cycle. Furthermore, before starting a correction cycle, the correction device detects whether the control member is in the aforementioned manual correction position and the control unit does not start a correction cycle if this is the case and so long. let this situation continue. The device for detecting whether the rod is in the time-setting position can easily be arranged along the control rod or the time-setting mechanism associated with this rod. We will advantageously opt for capacitive or magnetic detection (by placing a small magnet on the rod or on the associated mechanism). In an advantageous variant, each time the correction device detects that the external control member has been moved to its time-setting position, it rapidly performs a correction cycle as soon as this member is then replaced in another. position (in particular the winding position for a stem-crown).

To the Figure 7 there is shown the device for correcting the timepiece according to an advantageous variant of the first embodiment.

The timepiece comprises an energy recuperator 54 which can be formed by various types of devices known to the person skilled in the art, in particular a magnetic, light or heat energy recuperator, as well as an electricity accumulator 56. In a variant, the magnetic energy recuperator is arranged to receive energy from a source external magnetic for recharging the electricity accumulator 56 without electrical contact. In another 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 an electric current 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.

1. 1) La pièce d'horlogerie dispose d'un émetteur permettant d'indiquer directement à l'utilisateur que l'accumulateur doit être rechargé pour permettre d'effectuer une correction complète de l'heure affichée, par exemple via un signal optique (LED) ou acoustique engendré par l'émetteur. La pièce d'horlogerie n'effectue aucune correction tant que le niveau d'énergie électrique n'est pas suffisant pour une correction complète.
2. 2) La pièce d'horlogerie dispose d'un émetteur, notamment une unité de communication BLE, permettant d'indiquer à un téléphone portable ou autre dispositif électronique extérieure que l'accumulateur doit être rechargé pour permettre d'effectuer une correction complète de l'heure affichée, le téléphone portable comprenant une application pour indiquer à l'utilisateur cette information sur son affichage électronique. La pièce d'horlogerie n'effectue aucune correction tant que le niveau d'énergie électrique n'est pas suffisant pour une correction complète. Le téléphone portable peut en outre être utilisé pour recharger l'accumulateur d'électricité 56, de préférence sans contact, via le récupérateur d'énergie 54 ou via un autre dispositif de récupération d'énergie propre à un transfert d'énergie par un téléphone portable, par exemple par induction magnétique.
3. 3) La pièce d'horlogerie effectue seulement une correction partielle de l'heure affichée en utilisant l'énergie disponible dans l'accumulateur 56. Selon deux variantes, elle ne transmet aucune information à l'utilisateur ou elle informe l'utilisateur de cette situation via l'émetteur mentionné dans l'une ou l'autre des deux options précédentes.
4. 4) La pièce d'horlogerie ne transmet aucune information et n'effectue aucune correction tant que le niveau d'énergie électrique n'est pas suffisant pour une correction complète.

The control unit 48A controls a device 22 for braking the mechanical resonator 14, in particular an electromechanical actuator of the piezoelectric type shown schematically on FIG. Figure 1 . It will be noted that other types of actuators making it possible to momentarily apply a braking force to the mechanical resonator can be provided. As an option, the control unit comprises a circuit 68 for detecting the level of available electrical energy, this detection circuit supplying a signal S _NE to a control logic circuit 60 to give it information relating to the level of energy. available, so that this logic circuit can know if the correction module has sufficient energy before starting a correction operation. the time displayed. If this is not the case, the following various options are possible:

1. 1) The timepiece has a transmitter allowing direct indication to the user that the accumulator must be recharged to allow a complete correction of the displayed time, for example via an optical signal (LED ) or acoustic generated by the transmitter. The timepiece does not perform any correction until the level of electrical energy is sufficient for a complete correction.
2. 2) The timepiece has a transmitter, in particular a BLE communication unit, making it possible to indicate to a mobile phone or other external electronic device that the accumulator must be recharged in order to allow a complete correction to be made. time displayed, the mobile phone comprising an application to indicate this information to the user on its electronic display. The timepiece does not perform any correction until the level of electrical energy is sufficient for a complete correction. The mobile telephone can also be used to recharge the electricity accumulator 56, preferably without contact, via the energy recovery 54 or via another energy recovery device suitable for energy transfer by a telephone. portable, for example by magnetic induction.
3. 3) The timepiece only performs a partial correction of the displayed time by using the energy available in the accumulator 56. According to two variants, it does not transmit any information to the user or it informs the user of this. situation via the transmitter mentioned in either of the two previous options.
4. 4) The timepiece does not transmit any information and does not perform any correction until the level of electrical energy is sufficient for a complete correction.

In the absence of electrical energy management as indicated above, the timepiece can begin a corrective operation. required if the electric voltage available is sufficient and carry out this correcting 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 planned, 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.

The control unit 48A of the timepiece 2 comprises a control logic circuit 60 connected to the time base 42 and to the processing unit 46 which supplies it, as a correction signal Scor, the value of the. global time error T _Err determined during the previous processing phase. The control logic circuit is arranged to perform various logic operations during each correction cycle. In addition, the control unit 48A comprises a generator device 62 of a periodic digital signal having a _{given frequency F SUP} (the generator device 62 is also called frequency generator 'or simply' generator 'at the frequency F _SUP ). Depending on whether the overall time error T _Err to be corrected corresponds to a delay (T _Err negative) or an advance (T _Err positive) in the display of the real time, the control logic circuit 60 generates respectively either two signals control S1 _R and S2 _R , which it supplies respectively to the frequency generator 62 and to a time counter 63 ('timer'), or a control signal S _A that 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 PR _Cor for the correction of a delay and a period PA _Cor for the correction of an advance. By definition, an advance corresponds to a positive error and a delay corresponds to a negative error.

The following will first explain the arrangement of the control unit 48A for correcting a detected delay in the display of the time on the clock. during a correction phase following the detection and processing phases described above, and subsequently the arrangement of this unit to correct an advance during a correction phase.

In the case of a negative overall time 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 F _SUP , 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 S1 _R and the time counter 63 which counts or counts down a time interval corresponding to a correction period PR _Cor whose duration (the value) is determined by the logic circuit (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 countdown).

In the variant shown, when the frequency generator is activated, it supplies a periodic digital signal S _FS , at the frequency F _SUP , to another time counter 64 (timer at a value Tp corresponding to a duration selected for the braking pulses periodicals). The outputs of timers 63 and 64 are supplied to an 'AND'('AND') logic gate 65 which outputs a periodic activation signal S _C1 to periodically activate the braking device 22, during the correction period PR _Cor provided, via an “OR” (“OR”) logic gate 66 or any other switching circuit making it possible to transmit the periodic activation signal S _C1 to the braking device. The periodic activation signal S _C1 forms the control signal S _Cmd 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 F _SUP during a correction period PR _Cor , the duration (value) of which depends on the delay to correct. 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 the Figure 1 .

Preferably, as for the variant shown in Figure 1 , the system formed by 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 substantially at any time of 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 the document WO 2018/177779 already mentioned above, it is possible to precisely regulate the average frequency of an oscillating resonator by continuously applying periodic braking pulses to it at a braking frequency F _FR advantageously corresponding to double the setpoint frequency F0 _C divided by a positive integer N, _{i.e. F FR} = 2F0c / N. The braking frequency F _FR is 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 the 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 F _FR , a synchronous phase is established during which the oscillation of the mechanical resonator is synchronized, in average, on the reference 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, during the passage of the mechanical resonator through extreme positions of its oscillation, that is to say that 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, the document WO 2018/177779 indicates that synchronization can also be obtained for a braking frequency F _FR whose value is greater than twice the reference frequency (2F0), in particular for a value equal to M · F0 with M being an integer greater than two (M> 2). In a variant with F _FR = 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 braking frequency F _FR , the pulses in the synchronous phase which do not occur 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.

In the context of the development which led to the present invention, it has been brought to light that the remarkable phenomenon brought to light in the document WO 2018/177779 can be used not only to continuously synchronize a resonator to its setpoint frequency, but also to vary in a determined manner the oscillation frequency of a resonator in two frequency ranges located respectively below and above its reference 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 horological 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.

où N est un nombre entier positif.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 synchronization is carried out, during a period correction PR _Cor , the resonator oscillating on a correction frequency FS _Cor which is greater than the reference frequency F0c. It has been demonstrated in the context of the development which led to the present invention that, similarly to the case of synchronization on the reference frequency, the best results are obtained, for a correction frequency greater or less than the frequency of setpoint, when the braking frequency F _Bra is selected, for a _{given correction frequency F Cor} , so as to satisfy the following mathematical relationship: $${\mathrm{F}}_{\mathrm{Bra}}=\mathrm{2}\cdot {\mathrm{F}}_{\mathrm{Horn}}/\mathrm{NOT},$$

where N is a positive integer.

Thus, the periodic braking pulses are applied to the mechanical resonator at a braking frequency F _Bra advantageously corresponding to double the correction frequency F _Cor divided by a positive whole number N, preferably not very high. This relation is valid for a correction frequency F _Cor = FS _Cor which is greater than the reference frequency and also for a correction frequency F _Cor = FI _Cor which is lower than the reference frequency (first mode of correction of a advance which will occur subsequently in another embodiment of a timepiece according to the invention). The braking frequency F _Bra is therefore proportional to the planned correction frequency F _Cor and depends only 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 setpoint period T0c = 1 / F0c (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 reference frequency, other braking frequencies can make it possible to obtain, under certain conditions, synchronization on a desired correction frequency, but the selection of a frequency braking force F _Bra = 2 · F _Cor / N enables synchronization on the F _Cor frequency to be obtained more efficiently and with more stability. In general, the mathematical relationship between the braking frequency and the correction frequency is F _Bra = (p / q) · F _Cor 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 mixed numbers p / q which are appropriate and under what conditions (especially for which braking torque).

It will be noted that the braking pulses can be applied with a constant torque of force or a non-constant torque of force (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 .

To the Figures 8 and 9 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 F _INF = 2 FI _Cor with FI _Cor = 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 F _SUP = 2 · FS _Cor with FS _Cor = 1.00025 · F0c = 4.001 Hz, for the case of a natural frequency F0 = 3.9995 Hz. Figures 8 , 9 show the change in the frequency of oscillation of the resonator during a correction period, which is defined as the period during which the braking pulses at the frequency F _INF or F _SUP 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 F _INF leading to a correction frequency FI _Cor , given by the synchronization frequency, which is less 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 F _SUP leading to a correction frequency FS _Cor , given by the synchronization frequency, which is greater than the reference frequency (first mode of correction of a delay).

The very short correction period at Figures 8 and 9 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 at Figures 8 and 9 , 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 about 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, the Figures 8 and 9 are given only schematically to show generally 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 from it, and in the case of a natural frequency leading to a conventional 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, we observe at the start of the correction period a transient phase PH _Tr during which the frequency varies before stabilizing at the frequency FI _Cor , respectively FScor during a synchronous phase PHsyn which follows the transient phase. In the two cases shown, the transient phase PH _Tr is relatively short (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. We can refer to figures 9 to 11 of the document WO 2018/177779 where the transient phases to synchronize the resonator on the reference frequency F0c, from a close but different natural frequency, are longer. It will be noted that at the figure 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 natural frequency and stabilize at the frequency of setpoint.

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 gap resulting from a transient phase relative to the reference frequency. As an example, if F _Cor = 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 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 PR _Cor only on the basis of the overall time error T _Err to be corrected, by defining this correction period as being the period during which a series of periodic braking pulses is applied to the resonator at the expected braking frequency, and by assuming that the oscillation frequency during of the correction period is that of the synchronization frequency.

The synchronization frequency determines the correction frequency. By definition, the correction frequency F _Cor 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. Note 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 occur 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, the value of the correction period to be provided can be determined on the basis of the overall time error T _Err to be corrected, the setpoint frequency F0c and the correction frequency F _Cor ; 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 overall time error T _Err to be corrected, of the reference frequency F0c and of the braking frequency F _Bra . By definition, as already indicated, an advance in the time display corresponds to a positive error while a delay corresponds to a negative error. The following mathematical relationships are obtained to determine the value / value of the correction period: $${\mathrm{P}}_{\mathrm{Horn}}={\mathrm{T}}_{\mathrm{Err}}\cdot \mathrm{<figure-callout\; id="0"\; label="F"\; filenames="imgf0006.png,imgf0007.png"\; state="\{\{state\}\}">F</figure-callout>}\mathrm{0}\mathrm{vs}/\left(\mathrm{<figure-callout\; id="0"\; label="F"\; filenames="imgf0006.png,imgf0007.png"\; state="\{\{state\}\}">F</figure-callout>}0\mathrm{vs}-{\mathrm{F}}_{\mathrm{Horn}}\right)=\mathrm{2}{\mathrm{T}}_{\mathrm{Err}}\cdot \mathrm{<figure-callout\; id="0"\; label="F"\; filenames="imgf0006.png,imgf0007.png"\; state="\{\{state\}\}">F</figure-callout>}\mathrm{0}\mathrm{vs}/\left(\mathrm{2}\mathrm{<figure-callout\; id="0"\; label="F"\; filenames="imgf0006.png,imgf0007.png"\; state="\{\{state\}\}">F</figure-callout>}\mathrm{0}\mathrm{vs}-\mathrm{NOT}\cdot {\mathrm{F}}_{\mathrm{Bra}}\right)$$

In the first mode of correcting a delay (negative error), the correction frequency F _Cor = FS _Cor is greater than F0c, so that P _Cor is indeed positive. In this case the braking frequency F _Bra = F _SUP . We then have the relation: $${\mathrm{PR}}_{\mathrm{Horn}}={\mathrm{T}}_{\mathrm{Err}}\cdot \mathrm{<figure-callout\; id="0"\; label="F"\; filenames="imgf0006.png,imgf0007.png"\; state="\{\{state\}\}">F</figure-callout>}\mathrm{0}\mathrm{vs}/\left(\mathrm{<figure-callout\; id="0"\; label="F"\; filenames="imgf0006.png,imgf0007.png"\; state="\{\{state\}\}">F</figure-callout>}\mathrm{0}\mathrm{vs}-{\mathrm{FS}}_{\mathrm{Horn}}\right)=\mathrm{2}{\mathrm{T}}_{\mathrm{Err}}\cdot \mathrm{<figure-callout\; id="0"\; label="F"\; filenames="imgf0006.png,imgf0007.png"\; state="\{\{state\}\}">F</figure-callout>}\mathrm{0}\mathrm{vs}/\left(\mathrm{2}\mathrm{<figure-callout\; id="0"\; label="F"\; filenames="imgf0006.png,imgf0007.png"\; state="\{\{state\}\}">F</figure-callout>}\mathrm{0}\mathrm{vs}-\mathrm{NOT}\cdot {\mathrm{F}}_{\mathrm{SUP}}\right)$$

In the first mode of correction of an advance (positive error), the correction frequency F _Cor = FI _Cor is less than F0c, so that P _Cor is indeed positive. In this case the braking frequency F _Bra = F _INF . We then have the relation: $${\mathrm{PA}}_{\mathrm{Horn}}={\mathrm{T}}_{\mathrm{Err}}\cdot \mathrm{<figure-callout\; id="0"\; label="F"\; filenames="imgf0006.png,imgf0007.png"\; state="\{\{state\}\}">F</figure-callout>}\mathrm{0}\mathrm{vs}/\left(\mathrm{<figure-callout\; id="0"\; label="F"\; filenames="imgf0006.png,imgf0007.png"\; state="\{\{state\}\}">F</figure-callout>}\mathrm{0}\mathrm{vs}-{\mathrm{FI}}_{\mathrm{Horn}}\right)=\mathrm{2}{\mathrm{T}}_{\mathrm{Err}}\cdot \mathrm{<figure-callout\; id="0"\; label="F"\; filenames="imgf0006.png,imgf0007.png"\; state="\{\{state\}\}">F</figure-callout>}\mathrm{0}\mathrm{vs}/\left(\mathrm{2}\mathrm{<figure-callout\; id="0"\; label="F"\; filenames="imgf0006.png,imgf0007.png"\; state="\{\{state\}\}">F</figure-callout>}\mathrm{0}\mathrm{vs}-\mathrm{NOT}\cdot {\mathrm{F}}_{\mathrm{INF}}\right)$$

Following the general account relating to a correction of the rate of a mechanical timepiece obtained by a series of periodic braking pulses applied to its resonator, we can return to the first embodiment of the timepiece according to the invention. The 48A control unit ( Figure 7 ) is arranged to provide the braking device, each time the overall time error T _Err corresponds to a delay in the displayed time that is to be corrected, a control signal S _C1 derived from the periodic digital signal S _FS 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 of periodic braking pulses which are applied to the resonator at the frequency F _SUP . 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 F _SUP is provided and the braking device is arranged so that each series of periodic braking pulses at the frequency F _SUP 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 10 to 13B , a few observations relating to the braking pulses will be set out below, in particular concerning the braking frequencies F _Bra and the corresponding correction frequencies Fcor which are advantageously envisaged in a variant of the first mode of correcting a delay, and also in a preferred variant of a first mode of correcting an advance (which will be implemented in an embodiment described below) in which provision is made to correct a advance detected in the displayed time by a series of braking pulses at a frequency F _INF , already defined previously, resulting in a correction frequency FI _Cor , also defined previously, which is lower than the reference frequency F0c.

The Figure 10 shows a first part of a correction period with a relatively high ratio between the correction frequency FS _Cor = 3.5 Hz and the reference frequency F0c = 3.0 Hz (substantially equal to the natural frequency of the resonator when oscillates freely, represented by oscillation 82), namely a ratio RS = FS _Cor / F0c = 3.5 / 3.0 = 1.167. When applying to the mechanical resonator braking pulses 84 with a braking frequency F _Bra = F _SUP = 2 FScor = 7.0 Hz (case N = 1) and a sufficient braking force torque, allowing in the phase transient PH _Tr to sufficiently decrease 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 to say FScor = 3.5 Hz. It will be noted that already after one second the desired synchronization is obtained in the example given, but a phase PH _St for stabilizing the oscillation occurs at the start of the synchronous phase PH _Syn . 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 to the Figure 10 . By applying periodic braking pulses at the frequency F _SUP = 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 'saved' precisely 1 hour in 6 hours of 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).

The Figure 11 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 ( that is to say 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 reference frequency F0c is relatively high (i.e. 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 F _SUP = FS _Cor ). 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. F SUP = 2 FS _Cor ).

By appropriately selecting the braking torque and the braking frequency, it is observed that the correction frequency can vary continuously between the reference frequency F0c and a certain higher frequency FSC _max , for the correction of a delay in the hour. displayed, and continuously between the reference frequency F0c and a certain lower frequency FIC _max , to correct an advance in the displayed time. The upper frequency FSC _max and the lower frequency FIC _max 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 appropriate 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 of shutdown, which would lead to a shutdown of the display drive mechanism).

On the Figure 11 is indicated a safety angle θ _Sec below which, in absolute value, one will avoid stopping the mechanical resonator (i.e. between -θ _Sec and θ _Sec ), 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 θ _Sec is provided equal to or, preferably, greater than an angle θ _ZI (see Figure 14 ) 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 (-θ _ZI to θ _ZI ) between the mechanical resonator and the escapement (note that it is possible to brake in this prohibited zone during the transitional phase, but one will 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 θ _Sec is greater than the angle coupling θ _ZI . The person skilled in the art will know how to determine a value for the safety angle θ _Sec for each mechanical movement associated with a correction device according to the first embodiment. The angle of coupling θ _ZI 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 passage of time via the escapement (i.e. the timing of the time display drive mechanism) must continue during this delay correction period. Thus, very advantageously, said frequency F _SUP 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 of correction of a delay, the pulses of Periodic braking each takes place 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 F _INF 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 (ωt) 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 θ _ZI defined above. Finally, we consider the duration of the braking pulses very small, in fact punctual, by defining the braking frequency F _Bra as the inverse of the time value Tsec at which the resonator reaches, in the equation of motion given below. , the safety angle θ _Sec in the half-wave corresponding to the number N selected in the relation F _Cor = N · F _Bra / 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 θ _Sec . 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 ) θ _Sec in 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.

où τ = Q·T0/π, T0 est la période d'oscillation libre (considérée égale à T0c = 1/F0c pour les calculs) et θ ₀ est l'amplitude de l'oscillation libre.In this case, the equation of motion is given by: $$\theta \left(t\right)=\left({\mathrm{<figure-callout\; id="0"\; label="\theta "\; filenames="imgf0006.png,imgf0007.png"\; state="\{\{state\}\}">\theta </figure-callout>}}_0+\left({\theta }_{\mathit{Dry}}-{\theta }_0\right)e^{-\frac{t}{\tau }}\right)\times \mathrm{<figure-callout\; id="2"\; label="cos"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">cos</figure-callout>}\left(2{\mathit{\pi f}}_{0}t\right)$$

where τ = Q · T0 / π, T0 is the period of free oscillation (considered equal to T0c = 1 / F0c for calculations) and θ ₀ is the amplitude of the free oscillation.

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

To obtain a correction frequency FS _Cor 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: $$\theta \left(T_{\mathit{Dry}}\right)={-1}^{\mathrm{NOT}}{\theta }_{\mathit{Dry}}{\mathrm{with}T}_{\mathit{Dry}}\in \left[\frac{\left(2\mathrm{NOT}-1\right)}{4}{\mathrm{<figure-callout\; id="0"\; label="T"\; filenames="imgf0006.png,imgf0007.png"\; state="\{\{state\}\}">T</figure-callout>}}_0,\frac{\mathrm{NOT}}{2}{\mathrm{<figure-callout\; id="0"\; label="T"\; filenames="imgf0006.png,imgf0007.png"\; state="\{\{state\}\}">T</figure-callout>}}_0\right]$$

The maximum braking frequency FSB _max (N) = 1 / T _sec and the maximum correction frequency FSC _max (N) = N FSB _max / 2.

To obtain a correction frequency FI _Cor lower than the reference frequency F0c, T _Sec must occur in a half-wave before the passage of the resonator through its neutral / rest position. We therefore have for a given N: $$\theta \left(T_{\mathit{Dry}}\right)={-1}^{\mathrm{NOT}}{\theta }_{\mathit{Dry}}{\mathrm{with}T}_{\mathit{Dry}}\in \left[\frac{\mathrm{NOT}}{2}{\mathrm{<figure-callout\; id="0"\; label="T"\; filenames="imgf0006.png,imgf0007.png"\; state="\{\{state\}\}"><figure-callout\; id="2"\; label="T"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">T</figure-callout></figure-callout>}}_0,\frac{2\mathrm{NOT}+1}{4}{\mathrm{<figure-callout\; id="0"\; label="T"\; filenames="imgf0006.png,imgf0007.png"\; state="\{\{state\}\}">T</figure-callout>}}_0\right]$$

The minimum braking frequency FIB _min (N) = 1 / T _Sec and the minimum correction frequency FIC _min = N · FIB _min / 2.

The Figures 12A and 12B respectively represent the curves of RS _max (N = 1) = FSC _max (N = 1) / F0c and of RS _max (N = 2) = FSC _max (N = 2) / F0c as a function of the amplitude θ ₀ of 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 RS _max (N) ratio.

The Figure 13A gives, for a resonator having a quality factor Q = 100, a free amplitude θ ₀ = 300 ° and a safety angle θ _Sec = 25 °, the higher correction frequency ranges, for a reference frequency F0c and various values respective of N, which can be envisaged in the context of the first mode of correcting a delay, by representing the ratio RS = FS _Cor / F0c which extends between the value '1' and RS _max (N).

The Figure 13B gives, for a resonator having a quality factor Q = 100, a free amplitude θ ₀ = 300 ° and a safety angle θ _Sec = 25 °, the lower correction frequency ranges, for a reference frequency F0c and various values respective of N, which can be envisaged within the framework of the first mode of correction of an advance, by representing the ratio RI = FI _Cor / F0c which extends between RI _max (N) and the value '1'.

As indicated previously, the ranges given to Figures 13A and 13B derive 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 it in order to make large corrections in relatively short correction periods.

After having explained in detail the arrangement of the control unit and the operation of the correction device of the first embodiment of the timepiece according to the invention for correcting a delay in the time displayed by the timepiece horology, the arrangement of the 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 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 intended 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, the value / duration of which is 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 7 , the timepiece 2 comprises a locking device which is constituted by the braking device 22, in particular by the piezoelectric actuator 22A, which also serves to implement the first mode of correcting a delay. When the overall time error T _Err corresponds to an advance in the displayed time that it is intended to correct, the logic circuit 60 of the control unit 48A ( Figure 7 ) supplies a control signal S _A to the time counter 70 (timer) which is programmable. This timer 70 then generates a signal S _C2 for activating the braking device 22, via the 'OR'('OR') gate 66 or another switch, for a period of correction PA _Cor , the duration of which is substantially equal to the corresponding advance T _Err to be corrected. The periodic activation signal S _C2 then forms the control signal S _Cmd . It will be noted that the activation signal S _C2 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 PA _Cor = T _Err . 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 (-θ _ZI to θ _ZI ) 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 (-θ _Sec to θ _Sec ), described above. 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 rapid stopping of the resonator outside the aforementioned angular safety zone, a preliminary phase is provided which takes place before the correction period in which 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 to establish a synchronous phase where the resonator is synchronized on the frequency FS _Cor . 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 can vary from case to case, it is hardly possible to determine the error caused by the preliminary phase. However, it is possible to estimate a maximum error. For example, if the frequency F _SUP = 1.05F0c (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 to be 0.5 seconds (half a second). For a mechanical movement, if a 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.

With reference to the Figure 14 , a second embodiment of a timepiece according to the invention will be described which differs 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. 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 delay correction. 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 the 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 supply circuit 26A. The blade 24A has at its free end a projecting portion 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 short distance from this circumference. circular. The tray 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 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 14 , 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 walls lateral, 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 axis of rotation. 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 pad 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 vis-à-vis 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 determines during a correction cycle an overall time error corresponding to an advance in the time display, its control logic circuit, in a manner similar to the operation of the first embodiment, activates the blocking device 106, by supplying it with a control signal S _C2 similar to that described previously in the context of the first embodiment, for a period substantially equal to the overall 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 can be of another type than that shown in Figure 10 . For example, in a variant, the actuator can 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 that the stud is at least partially entering the hollow 108. Such a variant is particularly advantageous because the actuator must not exert any blocking force by applying a radial pressure on a member of the resonator balance in its two corresponding stable positions 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 the Figure 15 , a third embodiment of a timepiece according to the invention will be described, which essentially differs from the first embodiment by the arrangement of the locking device making it possible to advantageously implement the second mode of correcting a advance in the time display associated with the mechanical movement of the timepiece. The references already described in relation to the Figures 1 and 7 will not be described 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 has an operation which is similar to the braking device 22A already described, that is to say that it is also suitable for the implementation of the first mode of correction of a delay explained in detail previously. In the variant described here, the braking device 22B is formed by an electromechanical actuator of the electromagnetic type, that is to say comprising a magnet-coil system for actuating a flexible blade 240 embedded in a support 242 and whose end free form a brake element / shoe for the resonator 14. This actuator comprises a magnet 244, carried by the flexible blade, and a coil 246 located in front of the magnet and connected to a power supply 26B which receives the control signal S _C1 , which generates pulses of electric current in the coil to generate braking pulses. Each current pulse in the coil generates a magnetic flux which generates a force of magnetic repulsion on the magnet 244, and the flexible blade 240 then comes into contact with the lateral surface of the rim 20 of the resonator to generate a certain mechanical braking force on this resonator during a pulse braking.

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 with this blade, a second magnet 119 fixedly arranged relative to the mechanical movement (in the variant shown, the second magnet is inserted fixedly in a lateral opening of the support 242) and a ferromagnetic plate 120 arranged between the first magnet and the second magnet, a short distance from the second magnet 119 or against it (for example the wafer is glued against this magnet, only a layer of glue then separating the magnet from the wafer, or it is inserted fixedly in a housing of the support 242 located in front of the magnet 119).

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 and finally reversed when the mobile magnet comes close to 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 explained in detail in the patent application. CH 711889 , 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 from the magnetic assembly, formed by the fixed magnet. 119 and the ferromagnetic plate 120, which maintains the lever 115 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 on the part of said magnetic assembly which maintains the rocker 115 against this rim. The ferromagnetic plate 120 is arranged so that the blade 116 exerts a radial blocking force of the balance 16, and therefore of the resonator 14, when the lever is in its second stable position. In order for the blade 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 movable magnet 118, must be slightly recessed relative to the proximal surface of the blade. this moving magnet 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.

In order to move the bistable latch 115 between its two stable positions, in both directions, the locking device comprises a device for actuating this latch arranged to switch the latch alternately between its two stable positions. In the variant shown, the actuating device is formed by a coil 252 connected to an electrical supply 254. The coil 252 is aligned with the magnetic assembly, formed of the fixed magnet 119 and of the ferromagnetic plate 120, and arranged just behind the mobile magnet 118 when the latch is in its non-interaction position. Depending on the polarity of the electric voltage applied to the coil 252, the moving magnet undergoes a force of magnetic attraction or repulsion from this coil, thus making it possible to cause the rocker to pass from one of its two stable positions to the other in both directions. The actuating device is controlled by the logic circuit of the control unit via its supply circuit 254 which receives the control signal S _C2 . At the start of a lead correction period, the control signal generates a first pulse of electric current in coil 252 with a polarity which generates a repulsive force for the moving magnet 118 and a duration sufficient for the rocker goes into its interaction position, then the coil power is cut until the end of the correction period where a second pulse of electric current is generated in the coil with an opposite polarity, this second pulse then generating a force of attraction on the moving magnet which is provided sufficient to cause the rocker to switch towards its non-interaction position, thus ending the correction period.

In another variant, the device for actuating the rocker is provided separate and independent from the magnetic system of the bistable rocker. In this case, the electromagnetic system of the actuating device is formed by a second magnet carried by the rocker and a coil arranged opposite this second magnet, as in the previous variant. This electromagnetic system can be arranged upstream or downstream of said magnetic system relative to the pivot axis of the rocker.

What is remarkable in this embodiment is the fact that the blocking force exerted by the blocking device during the correction period does not come from a power supply of this blocking device, but from said magnetic system which the shape. Thus, the blocking device requires electric power only at the start and at the end of the correction period occurring in the second correction mode of an advance, during the switching of the flip-flop between its two stable states by the actuation device.

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 generally initially exerting a dynamic dry friction against the outer lateral surface of the rim, when the lever is actuated by the actuator to move from its first stable position to its second position stable at the start of a period for correcting an advance, before entering the hollow when the latter is presented in front of the stud during the oscillation of the balance.

With reference to the Figure 16 and the Figure 1 , 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 its mode of correcting a feed.

The power supply 130 of the correction device 132 comprises an energy recuperator formed by 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, an external control device 136 is provided to be able to provide an activation signal on request to the correction device, by a user of the timepiece, to trigger / start a correction cycle in the timepiece. of the displayed time (in other words to launch the method of 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 external control device 136 a wake-up signal. S _W-UP when this device is operated by a user. Once the management circuit 134 has received a 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 complete its completion. the correction process, the circuit management can react in various ways. He can in particular 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 a correction cycle while knowing that he may not be able to finish it correctly due to lack of energy available. In a variant, if the energy level is insufficient to carry out a complete correction cycle but sufficient to carry out a detection phase, the correction device already directly carries out such a detection phase by supplying only the parts necessary for this. detection phase, while waiting for a new supply of electrical energy in order to then be able to carry out a correction phase. Generally, when the level of energy available is sufficient for a correction cycle, the management circuit 134 activates the correction device to perform a correction cycle.

Since 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 a lead, already described previously but not implemented in the As a first embodiment, any correction provided herein is effected 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 Figure 16 , in the supply circuit 26C. This timer supplies an activation / actuation signal S _Act to 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 or with the flexible blade associated with the magnet-coil system ( Figure 15 ) of the third embodiment. Thus, the switch 138 controls the power supply to the actuator forming the braking device. The timer 64 receives a first control signal S1 _Cmd from a switching device 66A which is controlled by logic circuit 60A so that the first control signal is selectively formed by a periodic digital signal among three planned periodic digital signals S _FS , S _FI and S _F0c which respectively have three different frequencies F _SUP , F _INF 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 a global temporal error determined by the correction device corresponds to a delay to be corrected, the logic circuit 60A determines, as a function of the _{selected frequency F SUP} , a corresponding correction period PR _Cor or, in an equivalent manner, a number periodic braking pulses to be generated at the frequency F _SUP during the current correction cycle. To do this, he uses the formula relating to this determination which was established previously. To apply the series of braking pulses to the frequency F _SUP leading to a correction frequency FS _Cor greater than the reference frequency, it uses the frequency generator 62, already described, which supplies a periodic digital signal S _FS to the frequency F _SUP to timer 64 via switch 66A, which is controlled for this purpose by the logic control circuit.

When an overall temporal error determined by the correction device corresponds to an advance to be corrected, the logic circuit 60A determines, as a function of the _{selected frequency F INF} , a corresponding correction period PA _Cor or a number of periodic braking pulses to be generated at a frequency F _INF , 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 F _INF leading to a frequency of correction FI _Cor lower than the reference frequency, it uses the frequency generator 142 which supplies a periodic digital signal S _FI at the frequency F _INF to the timer 64 via the switch 66A, which is controlled for this purpose by the control logic circuit .

In general, to allow the implementation of the first mode of correction of an advance, the electronic control unit 48B is arranged to be able to supply the braking device, when the correction signal S _Cor supplied by the processing unit corresponds to an advance in the displayed time that it is planned to correct, a control signal derived from a periodic digital signal supplied by a frequency generator at a frequency F _INF , during a correction period, to activate the device braking so that it generates a series of periodic braking pulses applied to the mechanical resonator at the frequency F _INF . This frequency F _INF is provided and the braking device is arranged so that the series of periodic braking pulses at the frequency F _INF can generate, during the correction period, a synchronous phase in which the oscillation of the resonator mechanical is synchronized on a correction frequency FI _Cor which is lower than the reference frequency F0c 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.

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 risking to permanently stop 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 safety zone previously described. 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 16 , the correction device further comprises a frequency generator 144 which is arranged so as to be able to generate a periodic digital signal S _F0c at the reference frequency F0c provided for the resonator. The control unit 48B is arranged to be able to supply the braking device with a control signal derived from the periodic digital signal S _F0c , 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 setpoint frequency F0c. To do this, the control logic circuit 60A supplies the generator 144 with a control signal S _PP . 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 - θ _ZI and θ _ZI ) or, preferably, in a predefined safety zone (between - θ _Sec and θ _Sec ) encompassing 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 preliminary synchronous phase 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 S2 _Cmd , so that the voltage level applied to the braking member 24C can be varied to vary. 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. In a variant, the braking frequency during the preliminary period is equal to 2 · F0c; which also leads to synchronization on the frequency F0c by applying an alternating braking pulse.

The correction period, intended to correct an advance or a delay, directly follows the preliminary period. More precisely, the triggering of a first braking pulse at the frequency F _INF or F _SUP , 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 braking pulse 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; The consequence of this is that the resonator stops during the last braking pulse of this preliminary period. Thus, an inversion of the meaning 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 expected to so that the phase synchronous with the correction frequency FI _Cor or FS _Cor 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 succeeding 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 F _SUP or F _INF , depending on the correction required, following the instant at which the last pulse occurs. braking of the preliminary period. In another particular variant, said time interval is selected equal to the inverse of double the correction frequency FS _Cor or FI _Cor , depending on the correction required, or to the inverse of this frequency FS _Cor or FI _Cor . 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 temporal drift is induced by the preliminary period (generally at most T0c / 4). It will be noted that the generators at the various frequencies have been shown separately on Figure 12 , but only one programmable frequency generator device can be used.

With reference to Figures 17 to 19 , a fifth embodiment of a timepiece according to the invention will be described below. This fifth embodiment is arranged to allow the implementation of the second mode of correcting an advance, already described in previous embodiments, and a second mode of correcting a delay which will be described here in detail.

The timepiece 170 according to the fifth embodiment is shown in part on Figure 17 , 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 different reflection coefficients of 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 through 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 through 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 the direction of movement of the balance when the oscillating resonator passes through the specific angular position. Other types of detector for the position and direction of movement of the mechanical resonator can be provided in other variants, in particular capacitive, magnetic or inductive detectors.

Then, the timepiece 170 comprises a resonator braking device which is formed by an electromechanical device 174 with stopper. bistable mobile. An alternative embodiment, by way of nonlimiting example, is shown in Figure 17 . The electromechanical device 174 comprises an electromechanical motor 176, of the watchmaking stepper motor type of small dimensions, which is supplied by a supply circuit 178, which comprises a control circuit arranged to generate, when it receives a signal. control S4 _Cmd , a series of three electrical pulses which are supplied to the motor coil so that its rotor 177 advances by one step with each electrical pulse, or a half 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).

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 flip-flop, 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 positions of rest. 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 rest position corresponds to a magnetic repulsion position. Each time the control signal S4 _Cmd activates the power supply circuit so that it performs a series of three electrical pulses, the first magnet turns half a turn and the rocker alternately passes from a stable non-interaction position. 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 arrives at 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 out of 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. By "stable position", one understands a position in which the rocker remains in the absence of a power supply of the motor 176 which serves to actuate the rocker 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 θ _B 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 vibrations of each period of oscillation of the resonator. Then, the angle θ _B is expected to be less than a minimum amplitude of the oscillating mechanical resonator in its useful operating range. In addition, the angle θ _B 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.

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.

Finally, the timepiece 170 comprises a 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 control unit supplies the control signal S4 _Cmd . The control unit comprises a control logic circuit 198, a bidirectional time counter 200 and a clock circuit 44. This control unit is associated with the electromechanical device 174 to allow the implementation of the second mode of correction of a advance and also of the second mode of correcting a delay in the time indicated by the display of the timepiece, explained below.

To implement the second correction mode implemented in this fifth embodiment, the 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 planned to correct a delay or an advance in the time displayed by the timepiece, so that this stop device is moved from its position of no interaction at its interaction position respectively before the protruding part 190 reaches said first angular stop position θ _B during said second half-cycle of said first half-cycle of an oscillation period and before the protruding part 190 does not reach said second angular stop position during said first half-wave of said second half-wave 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 member stop momentarily prevents, after the protruding part has abutted against this stop member, the mechanical resonator from continuing the natural oscillating movement specific to this first half-cycle, so that this natural oscillating movement during the first half-cycle is momentarily interrupted before it is continued, after a certain blocking period which ends with the withdrawal of the stop device. Of preferably, in the case of a bistable electromechanical device as described above, provision is made to correct substantially the whole of a positive overall time error, determined by the device for correcting 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 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 stable position 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 T0c / 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, in order to at least partially correct 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 a so-called 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 resonator has passed through its neutral position), it thus prematurely ends 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 starts, following an instantaneous or almost instantaneous stop caused by the collision of the protruding part with the stop member, 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 error global time determined by the correction device 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 half-vibrations 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-waves 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 18 and 19 , the electronic control unit and the actuator are arranged so that, in order to at least partially correct a delay, the latch is maintained in its interaction position, following actuation of this latch 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 correction period during which the protruding part of the oscillating mechanical resonator comes periodically abut the head of the latch several times, the (duration of the) correction period during which the latch is maintained in its interaction position being determined by the delay to be corrected. Pivoting of the rocker from its non-interaction position to its interaction position can occur either in a so-called first alternation (the one 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 latch is placed in its interaction position before the protruding part reaches the stop angle θ _B , or in a so-called second alternation (also detected by detection of 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 (the stop angle is by definition less than or equal to 180 °). For example, if θ _B = 120 ° and the amplitude of the free oscillation of the resonator θ _L = 270 °, then we have in the second variant a time interval corresponding to a rotation between the angle '0' and a little less than 240 ° (360 ° -120 °), i.e. approximately 230 ° if the angle θ _T at the axis of rotation defined by the head of the rocker is approximately 10 °, to perform the pivoting of the rocker (so as not to block the balance by going beyond the position of the protruding part in the second half); whereas in the first variant there is only one time interval corresponding to a rotation between the angle '0' and 120 °. Note that if θ _L <360 ° - θ _B - θ _T , then we have much more time in the second variant to perform the pivoting of the rocker.

In general, in order to determine the duration of a period for correcting a delay, the control unit comprises a measuring circuit associated with the optical sensor, this measuring circuit comprising a clock circuit, supplying an output signal. clock 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 mechanical resonator from the start of the correction period. The control unit is designed for terminating the correction period as soon as said time interval is equal to or slightly greater than an overall time error determined by the correction device.

In the variant described in Figure 17 , the measuring circuit comprises a clock circuit 44, 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 / F0c) and at its input '+' a digital signal of 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 M _Cb ) is representative of a temporal drift of the mechanical resonator relative to the reference frequency which is determined by the clock circuit 44 having the precision of a quartz oscillator. The integer M _Cb 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 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 supply of the actuator 174 to effect the pivoting of the rocker, but after the control unit 196 and the optical sensor 192 are activated. In other variants, the optical sensor is replaced by another type of sensor, for example of the magnetic, inductive 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 overall time error T _Err (determined delay) is equal to -T _Err · 2 · F0c. Thus, as soon as the number M _Cb of the bidirectional counter reaches this value or exceeds it slightly (because this value is not in all cases an integer), the determined delay is made up and the time display is at new correct (it then gives the real time accurately, 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 -T _Err 2 F0c, and to end the correction period as soon as it detects that the number M _Cb is equal or greater. at 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.

To the Figures 18 and 19 the oscillations of the resonator 14A are shown, respectively in two extreme particular cases of the preferred variant described above, at the start of a period for correcting a given delay. The Figure 18 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 _{half-wave A2 L} before a detection of a time to when the resonator passes through its neutral position (position '0' of the projecting part 190) in the first half-wave which follows, the time to marking the start of a correction period for a given delay. The flip-flop is moved into its interaction position directly after time t ₀ . 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.

The Figure 19 relates to a particular case of a hard shock or elastic shock between the projecting part and the head of the rocker. 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 the time to, 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 θ _B. 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 on the other side of the head of the rocker relatively to the protruding part when it is in its angular position '0'. In practice, the impacts between the projecting part of the balance and the stop of the electromechanical device are generally between the two extreme situations described in Figures 18 and 19 .

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 powered) and activated (that is, it is powered). 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.

In a preferred general variant, the correction device is arranged so as to be activated periodically, automatically, to perform a correction cycle during which the detection device is activated during a detection phase, so as to allow the circuit electronic correction to determine an overall time error, and the braking device is then activated to correct, during a correction period, at least major part of this overall time error.

In a particular embodiment of the present invention, provision is made to use the braking device of the correction device and the internal clock circuit not only to correct a time error detected in the display of the real time, but also to implement a regulation as provided for in the document WO 2018/177779 already cited previously. According to the teaching of this document, a mechanical braking device is used, of the type described in the context of the present description, to impose on the oscillating mechanical resonator an average frequency which is synchronized on a reference frequency F0c determined by a circuit d internal electronic clock providing a periodic reference signal. To do this, the regulation device continuously and periodically activates the mechanical braking device at a braking frequency derived from the periodic reference signal. By virtue of such regulation, it is possible to effectively prevent a temporal drift of the oscillating mechanical resonator as long as the regulation device is active (in particular supplied with electricity). By advantageously combining the regulation device described in the document WO 2018/177779 with the correction device according to the present invention (using the mechanical braking device and the clock circuit in common), one can limit the frequency at which the correction device has to be activated, which can surprisingly lead to a decrease of electricity consumption despite the fact that the regulation device is still active.

Without the regulating device, the correction device is for example activated once a week to perform a correction cycle (with an otherwise relatively precise mechanical watch, it is thus possible to ensure that one minute of error is not exceeded). To fully benefit from the correction device and to have a watch whose error for the actual time displayed remains less than the usual daily error (in particular less than 10 seconds), the correction device is advantageously activated once a day. If we want to claim an accuracy of the order of a second, then it is necessary to periodically carry out correction cycles, for example every three or four hours; which then generates a relatively high electrical consumption. On the other hand, with an implementation of the regulation precedent (which a priori does not require any additional hardware resources), it is possible to automatically activate the correction device only once a month, or even less often, as long as that the mechanical movement works without stopping. However, it will be noted that it is not uncommon for a mechanical watch to be stationary if, for a movement of the classic automatic type, its user does not wear it a few days a week and if, for a winding movement manual, its user does not update it regularly. In such a case, following a subsequent winding of the barrel, the display must be reset to the correct real time, which is generally done manually by the user. In addition, the watch may be subjected to disturbances (for example shocks or strong accelerations that can cause a hand to slide on its axis, as well as the momentary presence of an intense external magnetic field, etc.). As already indicated, an external intervention (manual setting via an external control device) can also vary the display. In all these situations, the correction device according to the present invention is necessary to guarantee an accurate display of the real time by the watch. However, if the correction device is controlled by appropriate sensors or detectors so as to be activated following a disruptive or potentially disruptive event, in particular following a manual setting indicated above, the implementation of the regulation method in a timepiece according to the present invention may prove to be advantageous.

In an advantageous embodiment, the timepiece comprises an external control member operable by a user of the timepiece, this external control member and the correction device being arranged so as to allow a user to activate the correction device so that it performs a correction cycle during which the detection device is activated for a detection phase, so as to determine an overall time error, and the braking device is then activated to correct, during a correction period, at least for the most part this overall time error. In a particular variant, the external control member is formed by a crown associated with a control rod which also serve for setting the time. actual display manually. In a preferred variant, the possibility of controlling the correction device by an external control member so that it performs a correction cycle is combined with an internal automatic control which periodically activates the correction device so that it thus regularly performs a correction cycle. correction cycle.

With reference to Figures 20 to 24 , there will be described below a second embodiment of the detection device which is arranged in a timepiece 260 so as to be able to perform an indirect detection of the passage of at least one indicator of the display through at least one position corresponding reference time frame. In general, the detection device is arranged to be able to detect at least one respective predetermined angular position of a wheel integral with the indicator in question or of a detection wheel, forming the drive mechanism or complementary thereto. , which drives or is driven by the wheel integral with the indicator. Where appropriate, the detection wheel is selected or configured so as to have a rotational speed lower than that of the wheel integral with the indicator and a gear ratio R equal to a positive integer or the reverse of an integer depending on whether the detection wheel is driving or driven, respectively. The predetermined angular position which is detected by a detection unit of the detection device corresponds to a reference temporal position given for the indicator considered. Thus, the detection of the moment of passage of the wheel integral with the indicator or of the detection wheel by said predetermined angular position then makes it possible to determine a temporal error, as has been described previously for the first embodiment of the detection device relating to direct detection.

To the Figures 20 and 21 There is shown an advantageous arrangement of an optical detection unit 274 for detecting the passage of the seconds hand 262 through a given reference time position. This detection is carried out indirectly by the detection of an axis of specific reference AR of the second wheel 264 which carries this hand. The second wheel is conventionally driven in rotation by an average wheel 266 via the second gear 265. The second wheel 264 is in the example given in direct meshing connection with the escape wheel assembly which is formed of a escape wheel 268 and a pinion 269. The escape wheel 268 is coupled to the resonator of the mechanical movement in question.

The detection device comprises an optical detection unit 274 associated with the seconds hand 262 and arranged to be able to detect a predetermined angular position of the seconds wheel. This detection unit is similar to any optical detection unit described in connection with the first embodiment. It will be noted that a detection unit of another type can be provided, in particular of the capacitive, magnetic or inductive type. The reference axis AR, defining said predetermined angular position of the second wheel 264, is defined by a specific arm 288 of this wheel which has a width different from that of the other arms 286 of the wheel. This arm 288 has at least one reflecting zone in the region scanned by the light beam 232, emitted by the light source, when it passes under the detection unit 274. In order for the wheel to remain balanced, it will be noted that the arm 288 has a reduced thickness because it has about a double width relative to the other arms. The detection unit 274 is arranged on a support 280, in particular a PCB, and inserted into an opening of the plate 272.

Processing unit 46 ( Figure 1 ) determines the reference axis AR based on a series of measurements at a _{given measurement frequency F Ms} , similar to determining the middle longitudinal axis of the minute hand in the first embodiment of the detection unit, and thus the instant of passage of this middle longitudinal axis below the middle longitudinal axis of the detection unit 274, which comprises a light source 278 and a photosensitive detector 276 aligned along a direction radial of the second wheel. The superposition of the middle longitudinal axes of the specific arm and of the detection unit defines the predetermined reference time position. To use the notation used previously (during the description of the operation of the processing unit 46), said superposition of the middle longitudinal axes, during a detection phase, determines the instant of passage T _X0 of the needle of the seconds by the reference time position X0 . Thus, the watchmaker must angularly position the seconds hand relative to the seconds wheel so that, during said superposition of the middle longitudinal axes, the seconds hand indicates a current second corresponding to the predetermined reference time position.

To the Figures 22 to 24 is shown an advantageous system for detecting the passage of the minute indicator through at least one reference temporal position of the display of timepiece 260. This detection device is formed of an optical detection module 300, comprising two detection units, and a detection wheel which is specifically arranged for the intended detection. Each detection unit is similar to any optical detection unit described in connection with the first embodiment. Again, it will be noted that a detection unit of another type can be provided, in particular of the capacitive, magnetic or inductive type. The timer wheel has a gear ratio R = 1/3 with the road that drives it. It is therefore a reduction ratio between the driving roadway and the driven timer wheel. To the Figure 22 Also referenced is the barrel 292 which drives the center wheel 290. In another variant, the detection device only comprises a single detection unit.

As the 34M minute hand is carried by a roadway 296 which generally only has a central cylinder forming its axis and a pinion of small diameter, the indirect detection of the passage of the minute hand by at least one temporal position of given reference is so advantageously provided by means of a detection of at least one reference axis, among at least one series of given reference axes which respectively define a series of predetermined periodic angular positions, of the timer wheel 294 which is driven rotating by the roadway 296. This timer wheel forms a timer mobile whose pinion 295 meshes with the hour wheel 298 provided with a cylindrical axis carrying the hour hand 34H. It is arranged in a recess of the plate 272. The plate supports the timer wheel above and below the optical detection module 300, which is therefore arranged below the timer wheel. The plate has two through openings which are respectively provided above the two detection units for the passage of the light beam 232 between each of them and the timer wheel, more precisely the region in which the arms 306, 308 extend. of this timer wheel. Each detection unit has a light source 302, 302A and a photosensitive detector 304, 304A. The two optical detection units are arranged on a common support 310 which have two openings 312, 312A respectively aligned on the two detection units.

In general, the detection device comprises at least one detection unit associated with the minute indicator and arranged to be able to detect at least a first series of R given periodic angular positions of the timer wheel which are defined by a first series of R respective reference axes A1 _S1 , A2 _S1 and A3 _S1 . Two adjacent angular positions of this first series have between them an angle at the center α equal to 360 ° / R where R is said gear ratio (a = 360 ° / 3 = 120 ° with the gear ratio selected in the variant described). In the variant described, the detection module is furthermore designed to be able to detect also a second series of R given periodic angular positions of the timer wheel which are defined by a second series of R respective reference axes A1 _S2 , A2 _S2 and A3 _S2 which are different from the reference axes of the first series. Two positions adjacent angles of the second series having between them an angle at the center of the same value as the angle a, that is to say equal to 360 ° / R = 120 °. Advantageously, if S series of R periodic angular positions are provided, these S series being offset two by two by an angle equal to 360 ° / (R · S). In the variant shown, this angular offset angle is equal to 360 ° / 3 · 2 = α / 2 = 60 °.

Each series of periodic angular positions is associated with a respective plurality of R specific elements or specific recesses of the timer wheel. In the variant shown, there is a plurality of arms of the timer wheel, the first series of reference axes being defined respectively by three arms 306 having a first width and the second series of reference axes being respectively defined by three arms 308 having a second width different from the first width. The detection of each reference axis is carried out in a similar manner to the detection of the reference axis AR and the determination of an instant of passage of the minute hand through any of these reference axes is also carried out in a manner similar to determining the instant at which the seconds hand passes through the reference axis AR.

In a general variant, the timer wheel is configured so that each angular position of the first series has the same first signature for the correction device, so that the electronic correction circuit can associate one and the same first time position of reference to the minute indicator when detecting any angular position / any reference axis of the first series, and so that each angular position of the second series has the same second signature, different from the first signature, for the correction device, so that the electronic correction circuit can associate one and the same second reference time position, different from the first reference time position, with the minutes indicator when detecting any one angular position / of any reference axis of the second series. Thus, the electronic correction circuit can determine a second time of passage T _Y0 of the minute indicator through a reference time position Y0 (any one of the two reference time positions provided in the variant described) in an unambiguous manner.

In another general variant, the detection detection device comprises K detection units, K being an integer greater than one, and the number of series of periodic angular positions of the timer wheel is an integer S greater than zero, each series of periodic angular positions being associated with a respective plurality of R specific elements or specific recesses of the timer wheel. The K detection units are arranged to each be able to detect the S pluralities of R specific elements or specific recesses of the timer wheel. Any two of the K detection units are angularly offset by a separation angle of which the remainder of the entire division by an angle equal to 360 ° / (R · S) is other than zero. Preferably, the remainder of the integer division is substantially equal to 360 ° / (R · S · K). For the variant shown, 360 ° / (3 · 2 · 2) = 360 ° / 12 = 30 ° for the rest preferred. The separation angle β between the two radial detection directions defined by the arrangement of the two detection units has a value β = 90 °. The remainder of the integer division of β by an angle of 360 ° / (R · S) = 360 ° / (3 · 2) = 60 ° gives a value of 30 °; which corresponds to the above-mentioned preferred case.

Finally, it will be noted that the number of reference time positions of the minute indicator 34M that can be detected by the correction device with the second embodiment of the detection device is equal to S · K. In the variant shown, this number is equal to 2 · 2 = 4. These four reference time positions are shifted two by two by 15 minutes (corresponding to an angle of 90 °); which is equivalent to the advantageous variant shown for the first embodiment of the detection device.

Claims (45)

Timepiece (2; 112; 170; 260) comprising: - a display (12) of a real time, which is formed by a set of indicators comprising an indicator relating to a given time unit of the real time and indicating the corresponding current time unit; - 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; and - a device (6; 132) for correcting the real time which is indicated by the display; characterized in that the device for correcting the displayed real time comprises: - a detection device (30) arranged to allow the detection, directly or indirectly, of the passage of said indicator of the display through at least one reference time position of this display which is relative to said time unit of the hour real; - an electronic correction circuit (40), and - a braking device (22; 22A; 22A, 106; 22B, 114; 24C, 26C; 174) of the mechanical resonator; in that the electronic correction circuit comprises: - a control unit (48; 48A; 48B) arranged to control the detection device so that this detection device performs, during a detection phase, a plurality of successive measurements and supplies a plurality of corresponding measurement values, - a processing unit (46) designed to be able to receive said plurality of measurement values from the detection device and process it, and - an internal time base (42) comprising a clock circuit (44) and generating a real time reference composed of at least one unit current reference time corresponding to said current unit of time of the displayed real time; in that the electronic correction circuit is arranged and the duration of the detection phase is provided to allow the detection device to detect, while the drive mechanism is running and clocked by the oscillating mechanical resonator, at least one passage of said indicator through any reference time position of said at least one reference time position; in that the electronic correction circuit is arranged to be able to determine at least one instant of passage of said indicator through said any reference temporal position on the basis of at least one measurement value of said plurality of measurement values and an instant of corresponding measurement which is determined by the internal time base and composed of at least one corresponding value of said current reference time unit; in that the electronic correction circuit is further arranged to be able to determine a temporal error of said indicator, by comparing said at least one passing instant with said reference temporal position, and an overall temporal error (T _Err ) for said set of d indicators of the display as a function at least of said temporal error of said indicator; and in that the control unit is arranged to be able to control the braking device as a function of said overall time error, the braking device being arranged to be able to act, during a correction period, on the mechanical resonator, as a function of said overall time error, to vary the operation of the display drive mechanism so as to at least partially correct this overall time error. Timepiece according to Claim 1, characterized in that the control unit (48; 48A; 48B) and / or the processing unit (46) is / are connected to the internal time base ( 42) so as to be able to store said real reference time at at least one given instant of the detection phase; in that the electronic correction circuit (40) is arranged to be able to determine, during the detection phase, at least a first measurement moment and a second measurement moment corresponding respectively to at least a first measurement and a second measurement among said plurality of successive measurements, these first and second measurement instants being determined by the internal time base, the first measurement instant being composed of at least a first corresponding value of said current reference time unit and the second measurement instant being composed of at least a second value of this current reference time unit; the electronic correction circuit being arranged so as to be able to then calculate, as a function of said at least a first measuring instant and a second measuring instant and the corresponding measuring values, a third instant which determines said instant of passage of said indicator through said temporal position reference. Timepiece according to claim 1 or 2, wherein said display (12) comprises an hour indicator (34H) giving the current time, a minute indicator (34M) giving the current minute and a seconds indicator (34S ; 262) giving the current second of the displayed real time; and wherein said reference real time generated by the internal time base is composed of at least a reference current second and a reference current minute; characterized in that the detection device (30) is arranged to be able to detect the passage of the seconds indicator through at least one first reference time position of the display and the passage of the minutes indicator through at least one second reference time position of this display; in that the electronic correction circuit (40) is arranged and the duration of the detection phase is provided to allow the detection device to detect during this detection phase, while said drive mechanism (10) is running and clocked by the oscillating mechanical resonator (14), at least one passage of the seconds indicator by one any first reference time position of said at least one first reference position and at least one passage of the minute indicator through any second reference time position of said at least one second reference time position; in that the electronic correction circuit (40) is arranged to be able to determine, in association with the internal time base (42) and on the basis of measurement values of said plurality of measurement values, at least a first instant of passage of the seconds indicator through said any first reference temporal position, this first moment of passage being composed of at least one corresponding value of said second current reference, and at least one second moment of passage of the indicator of minutes by said any second reference time position, this second passing instant being made up of at least one corresponding value of said current reference minute; and in that the electronic correction circuit (40) is arranged to be able to determine a first time error for said seconds indicator (34S; 262), by comparing said at least a first moment of passage with said first reference time position, and a second time error for said minute indicator (34M) by comparing said at least one second passage time with said second reference time position; the electronic correction circuit being arranged to further be able to determine said overall time error (T _Err ) for the display (12) as a function of said first time error and of said second time error. Timepiece according to claim 3, characterized in that at least the minute indicator, among said set of indicators, is of the analog type, this minutes indicator displaying a positive whole number of minutes and a fractional part which is variable; in that the timepiece further comprises a time-setting device which is arranged so as to momentarily break the kinematic connection between the minutes indicator and the seconds indicator in order to effect a setting at the time of said posting; and in that the electronic correction circuit is arranged to be able to determine said overall time error (T _Err ) for said display furthermore as a function of at least one predefined correction criterion for the seconds indicator and / or the indicator minutes. Timepiece according to claim 4, characterized in that said overall time error is determined so as to substantially correct the first time error for the seconds indicator during said correction period. Timepiece according to claim 5, characterized in that said overall time error is determined so that the minutes indicator is present at the end of said correction period, in the event that this minutes indicator then has a time phase shift corresponding to a delay, at most a maximum delay which is selected in the range of values of said fractional part of the current minute displayed. Timepiece according to any one of the preceding claims, characterized in that , during the detection phase, the detection device (30) is activated so as to perform said plurality of successive measurements at at least one measurement frequency determined by said clock circuit (44) of the internal time base (42), this clock circuit supplying a periodic digital signal at the measurement frequency directly to the detection device or indirectly to this detection device via the control unit command (48; 48A; 48B). Timepiece according to claim 7 dependent on any one of claims 3 to 6, characterized in that said measurement frequency is variable; and in that the correction device (6; 132) is arranged to be able to detect the passage of the seconds indicator (34S; 262) through said at least one first reference time position with a first measurement frequency FS _Mes and the passage of the minute indicator (34M) through said at least one second time position of reference with a second measurement frequency FM _Mes which is lower than the first measurement frequency. Timepiece according to Claim 8, characterized in that the first measurement frequency FS _Mes is provided less than three times a reference frequency for said mechanical resonator and greater than or equal to 1 Hz, ie 1 Hz <= FS _Mes < 3 · F0c, while the second FM _Mes measurement frequency is expected to be less than or equal to 1/8 Hz (FM _Mes <= 1/8 Hz). Timepiece according to claim 8 or 9, characterized in that said first measurement frequency FS _Mes has a value different from twice the reference frequency F0c divided by a positive integer N, or FS _Mes ≠ 2 · F0c / NOT. Timepiece according to any one of claims 1 to 6, characterized in that the device (6; 132) for correcting the displayed real time comprises a sensor (192) associated with said mechanical resonator (14A) and arranged to be able to detect the passages of the oscillating mechanical resonator through its neutral position, corresponding to its position of minimum potential energy; and in that , during the detection phase, said detection device (30) is activated and controlled by said control unit (48; 48A; 48B) associated with the internal time base (42) to perform said plurality of successive measurements each following the detection of a passage of the mechanical resonator through its neutral position and after a certain time phase shift since this detection. Timepiece according to claim 11, characterized in that said time phase shift is between T0c / 8 and 3 · T0c / 8, where T0c is the setpoint period equal to the inverse of the setpoint frequency. Timepiece according to any one of the preceding claims, characterized in that the detection device (30) is arranged in the timepiece so as to be able to perform a direct detection of said passage of said indicator of the display by said at least one. a reference time position, this indicator being arranged to be able to be detected itself by the detection device. Timepiece according to claim 13, characterized in that the detection device (30) is of the optical type and comprises at least one light source (228), each capable of emitting a beam of light, and at least one detector photosensitive (227) each adapted to pick up light emitted by a light source of said at least one light source, said indicator having a reflection surface (RS1, RS2) which passes through the beam (s) of light emitted by said at least one light source when this indicator passes through said at least one reference temporal position, the detection device and the reflection surface being configured so that this reflection surface can reflect, during a passage of said indicator by any reference temporal position of said at least one reference temporal position, incident light, supplied by a light source of said at least one light source, to me ns partially towards a respective photosensitive detector of said at least one photosensitive detector. Timepiece according to claim 14, characterized in that said reflecting surface is formed by a lower surface of said indicator, said at least one light source and said at least one photosensitive detector being supported by a dial (32) of the timepiece or housed at least partially in the dial, or located under the dial which is then arranged to allow the beam (s) of light to pass through it. Timepiece according to claim 14 or 15, characterized in that the light emitted by said at least one light source is not visible to the human eye. Timepiece according to any one of claims 1 to 12, characterized in that the detection device is arranged in the timepiece so as to be able to perform indirect detection. of said passage of said indicator of the display through said at least one reference temporal position, the detection device being arranged to be able to detect at least one respective predetermined angular position of a wheel integral (264) of the indicator or of a detection wheel (294), forming the drive mechanism or complementary to it, which drives or is driven by the wheel integral with the indicator; and in that the sensing wheel (294), if applicable, is selected or configured so as to have a rotational speed lower than that of a rotating member (296) of said drive mechanism which is integral with said indicator and a gear ratio R with said rotating element equal to a positive integer or its inverse depending on whether the detection wheel is respectively driving or driven. A timepiece according to claim 17, wherein said indicator is a seconds indicator (262); characterized in that said wheel integral with the indicator is a seconds wheel (264), the detection device comprising a detection unit (274) associated with the seconds indicator and arranged to be able to detect a predetermined angular position of the second wheel. A timepiece according to claim 17, wherein said indicator is a minute indicator (34M); characterized in that said detection wheel is a timer wheel (294) which is rotated by a roadway (296) forming the rotating element integral with the minute indicator; and in that the detection device comprises at least one detection unit (302,304) associated with the minute indicator and arranged to be able to detect at least a first series of R given periodic angular positions of the timer wheel, two angular positions adjacent to this first series presenting between them an angle at the center equal to 360 ° / R. Timepiece according to claim 19, characterized in that said detection unit (302.304) is arranged to be able to detect also a second series of R given periodic angular positions of the timer wheel (294) which are different from the angular positions of the first series, two adjacent angular positions of the second series having between them a center angle of 360 ° / R; and in that the timer wheel is configured so that each angular position of the first series has a same first signature for the correction device (6; 132), so that the electronic correction circuit (40) can associate a one and the same first reference temporal position to the minute indicator during the detection of any angular position of the first series, and so that each angular position of the second series has the same second signature, different from the first signature, for the correction device, so that this electronic correction circuit can associate a single and same second reference temporal position, different from the first reference temporal position, with the minutes indicator upon detection of a any angular position of the second series. Timepiece according to claim 19 or 20, characterized in that the detection detection device comprises K detection units (302,304; 302A, 304A), K being an integer greater than one, and the number of series of positions periodic angular positions of the timer wheel (294) is an integer S greater than zero, each series of periodic angular positions being associated with a respective plurality of R specific elements or specific recesses of the timer wheel, the K detection units being arranged to each be able to detect the S pluralities of R specific elements or specific recesses of the timer wheel; and in that any two of the K detection units are angularly offset by a separation angle of which the remainder of the integer division by an angle equal to 360 ° / (R · S) is different from zero, the number of time positions of the minute indicator that can be detected by the correction device being equal to S · K. Timepiece according to claim 21, characterized in that the S series of periodic angular positions are offset two by two by an angle equal to 360 ° / (R · S) and said remainder of the integer division is substantially equal to 360 ° / (R · S · K). Timepiece according to any one of claims 19 to 22, characterized in that it comprises a plate (272) which supports the timer wheel (294) at the top and which carries the detection unit, which is arranged below. of the timer wheel. Timepiece according to any one of claims 18 to 23, characterized in that each detection unit is of the optical type and comprises a light source (302, 302A) and a photosensitive detector (304, 304A) aligned radially. Timepiece according to any one of the preceding claims, characterized in that the correction device (6; 132) is arranged so as to be periodically activated, automatically, to perform a correction cycle during which the detection device is activated for a said detection phase, so as to allow the electronic correction circuit (40) to determine a said global time error, and the braking device is then activated to correct, during a said correction period, at least by most of this global time error. Timepiece according to any one of the preceding claims, characterized in that it further comprises a control member operable by a user of the timepiece, this control member and the correction device being arranged so as to allow a user to activate the correction device so that this correction device performs a correction cycle during which the detection device is activated for a said detection phase, so as to determine a said global time error, and the device braking is activated to then correct, during a said correction period, at least most of this global time error. Timepiece according to Claim 26, characterized in that the said control member is formed by a crown associated with a control rod which also serve for setting the real time of the display manually. Timepiece according to any one of the preceding claims, characterized in that the correction device (6) further comprises a wireless communication unit (50) which is arranged to be able to communicate with an external system capable of providing the time. exact real time, the correction device being arranged to be able to synchronize the real reference time on an exact real time, composed of current time units of the exact real time corresponding to those of the real reference time, during a phase of synchronization during which the communication unit is activated so as to receive from the external system the exact real time or said exact real time. Timepiece according to claim 28, characterized in that said communication unit (50) is activated periodically, automatically, to effect synchronization of the reference real time on said exact real time during a said phase of synchronization. Timepiece according to claim 28 or 29, characterized in that it comprises a control member for the synchronization of the real reference time on said exact real time, this control member being operable by a user of the part. clockwork, the control member for synchronizing the reference real time on said exact real time and the correction device being arranged so as to allow a user to activate the correction device so that this correction device performs synchronization reference real time to said exact real time during a said synchronization phase. Timepiece according to Claim 30, characterized in that the said member for synchronizing the real time of reference on the said exact real time is formed by a crown associated with a control rod which also serve for setting the real time. display manually. Timepiece according to any one of the preceding claims, characterized in that it comprises a device (144; 192) for determining the passage of said oscillating mechanical resonator through at least one specific position, the device for determining this specific position of the resonator mechanical allowing said control unit to determine a specific time at which the oscillating mechanical resonator is in the specific position; and in that the 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 instant. Timepiece according to Claim 32, in which 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 (θ _B ) for the oscillating mechanical resonator which is different from its neutral position, corresponding to the state of minimum potential energy of the resonator mechanical, and less than a minimum amplitude of the oscillating mechanical resonator in its range of useful operation, said stop position being further provided so that the oscillating mechanical resonator is stopped by the stop member outside a coupling zone (θ _ZI ) of the escapement with oscillating mechanical resonator; and in that the circuit for determining said specific position of the oscillating mechanical resonator and said control unit are arranged so as to be able to activate the actuator, when said overall time error determined by the electronic correction circuit corresponds to a delay in the actual displayed time that it is intended 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 halves -alternations of the oscillating mechanical resonator which each follow its passage through said neutral position, so as to prematurely end each of these half-vibrations without blocking the mechanical resonator, the number of half-vibrations of said plurality of half-vibrations or a duration of the correction period during which the stop member is maintained in its interaction position being determined by the said delay to correct. Timepiece according to Claim 33, characterized in that the device for determining at least one 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 resonator mechanical being arranged to allow 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 correction circuit (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 the specific position is carried out; and in that the electronic correction circuit is arranged, so as to be able to at least partially correct said delay, so that it can control the actuator (174) so that this actuator actuates its stop member from its non-interaction position to his position of interaction 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 protruding part of the oscillating mechanical resonator abuts at least once against the stop member. Timepiece according to claim 34, 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 power supply for this actuator; and in that the electronic correction circuit and the actuator are arranged so that, in order to at least partially correct said delay, the stop member (184) is maintained in its interaction 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 during of which the projecting part (190) of the oscillating mechanical resonator periodically abuts several times against the stop member. Timepiece according to claim 34 or 35, characterized in that said control unit comprises a measuring circuit which is associated with said detector for the position and direction of movement of the mechanical resonator, this measuring circuit comprising a clock circuit (42), supplying a clock signal at a determined frequency (F0c / 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 in order to be able to measure a time interval corresponding to a time drift of the mechanical resonator since the start of the correction period, the control unit being arranged to end the correction period as soon as said time interval is equal or greater than said overall time error determined beforehand by the electronic correction circuit. Timepiece according to any one of claims 1 to 32, characterized in that the braking device is formed by an electromechanical actuator (22A; 22B) which is arranged to be able to apply braking pulses to the mechanical resonator, and the unit control comprises a generator device of at least one frequency (62) which is arranged so as to be able to generate a first periodic digital signal (S _FS ) at a frequency F _SUP ; in that the control unit (48A, 48B) is arranged to provide the braking device, when said overall time error determined beforehand by the electronic correction circuit corresponds to a delay in the displayed time that is expected to correct, a first control signal (S _C1 , S _Act (S _FS )) 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 frequency F _SUP , 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 F _SUP is provided and the braking device is arranged so that said first series of periodic braking pulses at the frequency F _SUP can generate, during said first correction period, a first synchronous phase wherein the oscillation of the mechanical resonator (14) is synchronized to a correction frequency FS _Cor which is greater than a setpoint frequency F0c provided for the mechanical resonator. Timepiece according to claim 37, characterized in that said device for generating at least one frequency is a device for generating frequencies (62,142) which is arranged so as to be able to further generate a second periodic digital signal (S _FI ) at a frequency F _INF ; in that the control unit (48B) is arranged to be able to supply the braking device, when said global time error determined beforehand by the electronic correction circuit corresponds to an advance in the displayed time which it is intended to correct, a second control signal (S _Act (S _FI )) 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 pulses of periodic braking which are applied to the mechanical resonator at said frequency F _INF , 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 F _INF is provided and the braking device is arranged so that said second series of periodic braking pulses at the frequency F _INF 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 FI _Cor which is lower than the reference frequency F0c provided for the mechanical resonator. Timepiece according to claim 37, in which the watch movement comprises an escapement associated with the mechanical resonator; characterized in that said frequency F _SUP and the duration of the braking pulses of the first series of periodic braking pulses are selected so that, during said first synchronous phase, the braking pulses of said first series each occur outside of 'a coupling zone (θ _ZI ) between the oscillating mechanical resonator and the escapement. Timepiece according to claim 38, wherein the watch movement comprises an escapement associated with the mechanical resonator; characterized in that said frequency F _INF and the duration of the braking pulses of the second series of braking pulses periodic are selected so that, during said second synchronous phase, the braking pulses of said second series each intervene outside a coupling zone (θ _ZI ) between the oscillating mechanical resonator and the escapement. Timepiece according to any one of claims 37 to 40, characterized in that the device for generating at least one frequency is a device for generating frequencies (62,142,144) which is arranged so as to be able to further generate a third periodic digital signal (S _F0c ) at the reference frequency F0c for the mechanical resonator; in that the control unit is arranged to be able to supply the braking device with a third control signal (S _Act (S _F0c )) derived from the third periodic digital signal, during a preliminary period preceding the correction period, to activate the braking device such that this braking device generates a preliminary series of periodic braking pulses which are applied to the mechanical resonator at the setpoint frequency F0c, 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 (θ _ZI ) of the oscillating mechanical resonator with the escapement; the control unit being 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 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 time interval determined with respect to an instant at which the last braking pulse of the preliminary period, the instant of triggering of said first braking pulse and the braking force applied to the oscillating mechanical resonator during said first series of periodic braking pulses being provided such that said first phase synchronous with said correction frequency FS _Cor starts from said first braking pulse or a second braking pulse. 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 control unit is arranged to be able to supply the blocking device, when said overall time error determined beforehand by the electronic correction circuit 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. Timepiece according to Claim 42, characterized in that the said correction period has a duration substantially equal to the said advance to be corrected. Timepiece according to claim 42 or 43, characterized in that the locking device is formed by a device (114) separate from said braking device and comprises a bistable latch (115), the first stable position of this corresponding bistable latch to a position of non-interaction with the mechanical resonator and its second stable position corresponding to a stopping and locking position of the mechanical resonator. Timepiece according to any one of claims 42 to 44, characterized in that the locking device (106) forms a lock for the mechanical resonator, a part (107) of this locking device coming to be inserted in 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.

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