CH717000A2 - Timepiece fitted with a mechanical movement and a device for correcting a displayed time. - Google Patents

Abstract

The timepiece according to the invention, in particular a watch (2), is formed by a mechanical movement (4) incorporating a mechanical resonator (14). It comprises: - a display of the real time (12), - a correction device (6) formed by a device (30) for detecting the passage of an indicator (34) 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 (6) 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 (6) is arranged so that the braking device (22A) can act on the mechanical resonator (14) during a correction period to vary the rate of the drive mechanism. display, so as to correct the actual time displayed. According to one embodiment, the correction device (6) comprises a wireless communication unit (50) arranged to be able to communicate with an external system capable of providing the exact real time.

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

Summary of the invention

[0003] It can therefore be seen that in the field of timepieces fitted with a mechanical movement, in addition to ensuring precise operation of this mechanical movement, a real need exists for an effective system for correcting the real time. displayed by those timepieces comprising a mechanical movement. In particular, the present invention aims to be able to set the 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 put 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 appreciation of the user who has to estimate when the various indicators concerned are in the correct respective positions.

The term "real time" is understood to mean the legal time of a given location, in which the timepiece and its user are generally located. Actual time is typically displayed in hours, minutes, and, if applicable, seconds. The real time can be indicated with some error by a timepiece, especially of the mechanical type. 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.

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

Although the indicators used to display the real time all relate to one and the same physical quantity, time, in this description the hour, minute and second are considered 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 presents 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 usually a fractional part (sexagesimal part) in seconds (always the case in an analog display of real time). The current time displayed includes at least a whole 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 made up 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 minutes indicator giving the current minute and a seconds indicator giving the current second of the real 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 reference 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 indicator of the seconds 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 current reference at said first passing instant, and at least a second instant of passage of the minute indicator through said second reference time position, this second time of passage also being determined by the real reference time and composed of at least the value of the current minute of reference to said second time of passage. 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 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.

In an advantageous embodiment, the detection device is arranged in the timepiece so as to be able to perform direct detection of the passage of an indicator of the display through at least one corresponding reference time position, this indicator being designed 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 detection device 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 to the latter, which drives or which 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 generating at least one frequency which is arranged so as to be able to generate a periodic digital signal at a frequency FSUP. The control unit is arranged to provide 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 FSUP. 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 FSUP is provided and the braking device is arranged so that the series of periodic braking pulses at the frequency FSUP can generate, during the correction period, a synchronous phase in which the oscillation of the mechanical resonator is synchronized with a correction frequency FSCorqui 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 FSUP 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 locking 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, to stop the operation of the drive mechanism during this correction period.

Brief description of the figures

The invention will be described below in more detail with the aid of the accompanying drawings, given by way of non-limiting examples, in which: Figure 1 shows, in part schematically, a first embodiment of 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; Figure 2 is a top view of the timepiece of Figure 1; Figure 3 is a partial section of the timepiece of Figures 1 and 2, according to a first variant of a first embodiment of the detection device; Figures 4A to 4D are schematic cross sections of various variants for a light source forming the detection device according to the first embodiment; 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 detection device of the timepiece of Figures 1 and 2; FIG. 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 seconds hand and a temporal error of the second hand. minute hand; FIG. 7 schematically represents a variant of the device for correcting the timepiece according to the first embodiment; Figures 8 and 9 show, during a correction effected by a series of periodic braking pulses, the evolution of the oscillation frequency of a mechanical resonator during a period of correction of an advance, respectively of a period for correcting a delay in the time indicated by a display of the timepiece considered, and this for the case of a ratio between the correction frequency and the setpoint frequency relatively close to one ; 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 periodic braking pulses, this correction period having an initial transient phase; FIG. 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; 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; 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; FIG. 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 braking frequencies selected for the braking pulses; 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, as a function of several braking frequencies selected for the braking pulses; FIG. 14 partially shows a second embodiment of a timepiece according to the invention; FIG. 15 partially shows a third embodiment of a timepiece according to the invention; FIG. 16 schematically represents a fourth embodiment of a timepiece according to the invention; FIG. 17 schematically represents a fifth embodiment of a timepiece according to the invention; 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 Figure 17; 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 relation to a first unit for detecting the passage of the light. second hand by a corresponding reference time position; Figure 21 is a top view of the seconds wheel of the mechanical movement forming the timepiece of Figure 20; Figure 22 is a second partial section through the timepiece of Figure 20, in relation to a second unit for detecting the passage of the minute hand through a corresponding reference time position; Figure 23 is a top view of the timing mobile of the mechanical movement forming the timepiece of Figure 22; and Figure 24 is a top view of the second unit of the timepiece detection device of 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, i.e. 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 minute and second hands are coaxial), the seconds indicator has a temporal / angular position which is arbitrary (position any 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.

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 circuit of correction 40 includes: 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 SMs, and to process it, an internal time base 42 comprising a clock circuit 44, this internal time base generating a real reference time 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 electronic correction circuit 40 associated with the detection device 30, which is arranged to be able to detect the passage of the seconds hand 34S through at least a first reference temporal position of the display and the passage of the indicator of minutes 34M by at least a 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 SCmd to control its supply circuit so as to temporally manage the application of a mechanical braking force to the mechanical resonator 14. De In general, the correction device is arranged so that the braking device can act, whenever 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 has on two opposite surfaces (perpendicular to the plane of Figure 1) respectively two piezoelectric layers which are each coated with 'a metallic layer forming an electrode. The piezoelectric actuator comprises a supply circuit 26 making it possible to apply a certain voltage between the two electrodes so as to apply an electric field through the two piezoelectric layers, which are arranged so as to bend the blade 24 in the direction of the serge 20 of the balancer 14, when a voltage is applied between the two electrodes, so that the end part of the blade, forming a movable brake shoe, can press against the outer circular surface of the serge and thus exert a force mechanical brake on the mechanical resonator. It will be noted that the voltage can be variable, in order to vary the mechanical braking force and therefore the mechanical braking torque applied to the balance. Regarding the braking device, reference may be made to document WO 2018/177779 for various alternative arrangements of such a braking device in a mechanical watch movement. In a particular variant, the braking device is formed by a blade actuated by a magnet-coil system. In another particular variant, the balance comprises a central shaft which defines or which carries a part other than the rim of the balance, for example a disc, defining a circular braking surface. In the latter case, a shoe of the braking member is arranged so as to exert pressure against this circular braking surface during the momentary application of a mechanical braking force.

The 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 the passage of at least one indicator of the analog display 12, relating to a time unit of the real time, through 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 laFigure 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 seconds hands 34S ( 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.

Figure 3 is a partial section of the watch of 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 rotates the seconds hand and the minute hand. 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 arrays 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, in Figure 3, one above the other to aid in understanding 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 linked to the desire for flat and horizontal reflecting surfaces for the needles concerns firstly the light source. In Figures 4A to 4D are shown four specific variants 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 luminous intensity profile, shown in FIG. 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 α0. 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 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 inclined planes in Figure 3 exhibit an angle of approximately 45 °, the inclined planes of the RD refraction grating exhibit a smaller angle relative to the horizontal direction (e.g. 35 °), so as to have an angle of refraction for the light beam 232 which allows it to pass through the transparent structure.

Two variants, where one accepts a particular treatment of the lower surfaces of the needles concerned, are shown in Figures 5A and 5B. Note that these two variants can be complementary to the variants described above. In Figure 5A, the needle 34D has a reflective 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. In Figure 5B, needle 34R has a reflection grating in an area of its lower surface which passes through 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.

Referring to Figure 6, we will now describe a detection phase, provided at the start of a correction cycle of the displayed time, for the main embodiment in which the real time of reference TRfgenerated by the time base internal 42 is made up of at least one current second of reference XR and one current minute of reference YR.

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 one passage of the minute indicator through a reference time position from 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 base of internal time 42 and on the basis of measurement values of a plurality of measurement values, at least a first time of passage TX0 of the seconds indicator through any reference time position, named X0, among the positions reference times provided for this seconds indicator, this first passing instant being made up of at least one corresponding value of the current reference second XR, and at least one second passing instant TTY0 of the minutes indicator through any second position reference time, 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 YR. 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 FMs. 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 measuring frequency FM to generate a plurality of light pulses, and the photosensitive detector provides a plurality of values of. corresponding light 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 internal time base 42, this clock circuit supplying a periodic digital signal at the measurement frequency FMsdirectly 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 FSMeset the passage of the indicator. minutes by the reference time position Y0 with a second measurement frequency FMMes which is lower than the first measurement frequency. In a particular variant, the first measurement frequency FSMes 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 <= FSMes <3 · F0c, while the second frequency measurement FMMes is expected to be less than or equal to 1/8 Hz (FMMes <= 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 is noticeably still during 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 measurements from occurring when the seconds hand undergoes a small rotational movement, provision is made, in an advantageous variant, for the first measurement frequency FSM to have a value other than double the reference frequency F0c divided by a positive integer N, that is FSMes ≠ 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 setpoint period which is equal to the inverse of the setpoint frequency. To do this, the clock circuit 44 is designed to supply the control unit with a periodic signal at a frequency equal to 8 / TOc 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. On the second flank considered, the control unit triggers a measurement 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 FMs = 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.

In Figure 6 is shown a first series of measurements performed for the detection of the second hand at a first frequency FSMs = 4 Hz, preferably using the advanced variant described above if the setpoint frequency for the mechanical resonator is also equal to 4 Hz, and a second series of measurements at a second frequency FMMs = 1/10 Hz (every 10 seconds to save energy) since the minute hand turns 60 times less faster than the seconds hand 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 FMM frequency 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 VSn, n being a positive integer, to which corresponds a first series of measurement times TSn. The second series of measurements gives a second series of intensity values VMk, k being a positive integer, to which a second series of measurement instants TMk corresponds. Thus, to each measurement corresponds a pair of values VSnet TSn, respectively VMket TMk.

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 by chronological order of the measurements of each series of measurements, and establish a temporal link with the real time reference TRf for each series of measurements. In the case of a numbering which associates a number n, respectively k with each value VSn, respectively VMk, the periodic digital signal at the measurement frequency FMs (periodic measurement signal) can also be supplied to the processing unit 46 which receives the measurement values via an SM signal supplied to it by the detection device, directly or via the control unit. In the case of a 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 TMs which is the inverse of the measurement frequency FMs. 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 TSRf, X for the seconds hand, respectively TMRf, 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 measure corresponds to a real reference time determined. This temporal relation can be expressed mathematically as follows: TSn = (n-X) / FSMs + TSRf, X TMk = (k-Y) / FMMs + TMRf, Y

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 into consideration 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 TSRf, X, respectively TMRf, 0. Thus, we have: TSn = n / FSMs + TSRf, 0 with n = 1 to N TMk = k / FMMs + TMRf, 0 with k = 1 to K where N and K are the numbers of measurements for the detection of the seconds hand and the minute hand, respectively.

The processing unit 46 performs a processing of each series of measurements to determine the first time of passage TX0 of the seconds indicator by the reference time position X0 and the second time of passage TTY0 of the minute indicator by the time position of referenceY0. Various methods of processing measurement data can be used. By way of examples, we will cite the two examples in connection with FIG. 6, and a simplified example. To determine the value Tx0, given that the seconds hand is relatively thin and turns relatively quickly, an algorithm determines the maximum value VSmax to which corresponds a rank / number n = ZE. ThusTX0 = ZE / FSMs + TSRf, 0 In Figure 6, TX0 = 10 s and 250 ms (TX0 = 10.25 s).

To determine the valueTY0, an algorithm determines a width, corresponding to a time interval IT, substantially halfway up a symmetrical convex curve CFitjusted to the series of measurement values VMk to be able to determine a middle value of this width , this middle value defining the instant of passage TY0 of the longitudinal middle 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 d 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 VMk. It is observed here that the value TY0 does not correspond to an integer rank / number (the measurements intervening here only every 10 seconds), but it corresponds to a fractional number ZF intermediate between two adjacent ranks / numbers. SoTY0 = ZF / FMMs + TMRF, 0

In Figure 6, TY0 = 17 minutes and 48 seconds (TY0 = 17 min; 48 s) .TY0 therefore has an integer value PMY0 in minutes (integer part of TY0) corresponding to the current reference minute during the passage of the indicator by the reference time position Y0, to which is added a value PSY0 in seconds which defines a fractional part for the current minute given by the minutes indicator when the indicator passes through the reference time position Y0, this value PSY0 corresponding to the current reference second when the minute indicator passes through the reference time position Y0. We will thus denote byTY0 = (PMY0; PSY0). Note that the value PSY0 may possibly have decimals. In a simplified variant, we can ignore PSY0, but then we lose a lot of precision for the minute hand. Thus, in the main embodiment, the instant of passage of the minute hand 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 (sexagesimal part), 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 set memory the real time of reference at at least a given instant of the phase of detection. 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 a first corresponding 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 measuring instant and a second measuring instant and the corresponding measuring values, a third instant which determines the instant 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 attributes the moment of this measurement to the moment of passage and it records the value of the real time of reference 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 time error for the seconds indicator, by comparing at least a first passing instant of this indicator of the seconds. seconds with a first corresponding reference time position, and a second time error for the minutes indicator by comparing at least a second moment 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.

For the seconds indicator and the minutes indicator, the two respective time errors EsetEM are given by: Es = Tx0- X0; EM = TY0- Y0

By construction, X0 corresponds to an integer number of seconds and YO corresponds to an integer number of minutes, ie Y0 = (Y0; 0). Es is given in seconds, possibly with one or more decimal places since TX0 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 passage instantTY0determined for the minutes indicator has an integer partPMY0 in minutes and a fractional partPSY0 in seconds, the time errorEMis determined with an integer partEMmen minutes and a fractional partEMsen seconds (EMss thus adding to EMm). According to the chosen notation: EM = (EMm; EMs). It will be noted that EMS 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 EMsen seconds since this value is already a fractional part for the minutes indicator.

We formally note: EM = (EMm; EMs) = (PMY0; PSY0) - (Y0; 0) = (PMY0- Y0; PSY0).

In the example of Figure 6: X0 = 15 s andEs = 10.25 - 15 = -4.75 s Y0 = (15; 0) andEM = (17; 48) - (15; 0) = (2; 48), i.e. 2 min and 48 s.

It is observed that the fractional part EMsde the time error EMrelative to the current minute displayed by the minutes indicator is quite different from the time error Es 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 generally arises from the following two facts: 1) An actual time display is formed 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) 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, it has been provided that the electronic correction circuit can also determine an overall time error TErr, for the display of a watch of the mechanical type, as a function of the first time error determined for the seconds indicator, the second time error determined for the minutes 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 display of the timepiece.

In a preferred mode of processing 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 should correctly indicate the current second, ie 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 Tmax, or greater than or equal to-Tmax

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 integer number of minutes and a part fractional which is variable. Then, the timepiece further comprises a time-setting device which is arranged so as to momentarily break the kinematic link 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 (TErr) for the display as a function of at least one predefined correction criterion for the seconds indicator and / or the additional minutes indicator. first and second time errors relating respectively to the seconds and minutes indicators.

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 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.

In a preferred variant, the processing algorithm implemented in the processing unit 46 to determine the overall temporal error TERrest as follows: • A cumulative error ECMs is calculated, relating to the fractional part in seconds of the current minute displayed by the minutes indicator, theoretically applying the first correction criterion, namely by subtracting the time error ES of the seconds indicator from the fractional part EMs from the time error EM of the minutes indicator, namely: ECMS = EMs- ES • One carries out the whole division of the cumulated errorECMs by sixty (this operation is noted 'ECMsmodulo 60'); which gives a quotientQM (whole number of minutes) and a remainder Rs in seconds (positive). • A maximum delay Tmax is selected for the minute indicator, according to the second correction criterion. • A global error EMG is determined for the value relating to the minute in the global temporal error TErr, this global error EMG being able to take two different values as a function of the remainder RS of said integer division and of said maximum delay Tmax, namely: EMG = EMm + QMsi Rs belongs to the range [ 0; 59 - Tmax] EMG = EMm + QM + 1si Rs belongs to the range [60 - Tmax; 59] for the case where Tmax is greater than zero. • The global temporal error to be corrected is defined: TErr = (EMG; ES) where EMG is an integer number of minutes, and Es is formed by an integer number of seconds with possibly one or more decimal places.

Thus, in the example of Figure 6, by selecting Tmax = 15 s: ES = -4.75 s, EM = (2 min; 48 s); ECMs = 48 + 4.75 = 52.75 s ECMsmodulo 60 gives: QM = 0; RS = 53 s (rounded value) EMG = EMm + QM + 1 = 2 + 0 + 1 = 3; TErr = (EMG; ES) = (3; -4.75).

It will be noted that the variant Tmax = 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 some advance between '0' and '59' seconds. A selection of Tmax = 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 Tmax = 15 s may prove to be advantageous, a good compromise.

As a complement, here are three examples (with Tmax = 15 s): Example 1 ES = 25 s, EM = (- 2 min; 19 s); ECMs = 19 - 25 = - 6 s ECMsmodulo 60 gives: QM = -1 min; RS = 54 s EMG = EMm + QM + 1 = -2-1 + 1 = -2; TErr = (-2; 25) = (-1; -35) Example 2 ES = - 30 s, EM = (- 2 min; 36 s); ECMs = 36 + 30 = 66 s ECMsmodulo 60 gives: QM = 1; RS = 6 s EMG = <> EMm + QM = -2 + 1 = -1; TErr = (- 1; -30) Example 3 ES = 5 s, EM = (1 min; 42 s); ECMs = 42 - 5 = 37 s ECMsmodulo 60 gives: QM = 0; RS = 37 s EMG = EMm + QM = 1 + 0 = 1; TErr = (1; 5)

The determination of the overall temporal error TErrest 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 SCorf supplied by the processing unit comprises either the value TERr or the values ESetEM. 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 overall correction of the display of the watch to be performed during a correction cycle is given by-TErrconverted entirely in 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 hour hand which is normally in phase with the minute hand and continuously in mesh with this minute hand, only the difference between the current time displayed and a current reference time given by the base of time is taken into account to determine the overall time error.

In another particular embodiment, the timepiece only comprises an indicator of the current time 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 SSync providing an exact real time or an 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 receiving an SSync signal, the communication unit 50 supplies the exact real time HRE or said exact real time to the internal time base 42 which then synchronizes the real reference time / the real reference time to the internal time base 42. exact real time / that 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 time of reference to 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 of the 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 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 detection phase, the control unit interrogates the status bit to know 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 the synchronization of the real reference time on the exact real time, this external control member being operable by a user of the part. watchmaking. 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 relation to 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 prevent a correction cycle by the correction device according to the invention from being 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). A mechanism can be provided to block the external control member (the stem-crown) so that it cannot modify the position of the minute hand and / or stop the seconds hand during a cycle. correction. This normally requires an electromechanical actuator, which makes the timepiece more complex. An alternative is to arrange for the displacement 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).

In laFigure 7 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 recuperator of magnetic, light or heat energy, as well as an accumulator of electricity 56. In a variant, the magnetic energy recuperator is arranged to receive energy from an external magnetic source making it possible to recharge the electricity accumulator 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.

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 in Figure 1. It will be noted that other types of actuators making it possible to momentarily apply a Braking force at the mechanical resonator can be provided. As an option, the control unit comprises a circuit 68 for detecting the level of electrical energy available, this detection circuit supplying a signal SNE to a control logic circuit 60 to give it information relating to the level of electrical energy at provision, so that this logic circuit can know if the correction module has sufficient energy before launching an operation to correct the displayed time. If this is not the case, the following various options are possible: 1) The timepiece has a transmitter allowing direct indication to the user that the accumulator must be recharged to enable a complete correction of the displayed time, for example via an optical (LED) or acoustic signal generated by the transmitter. The timepiece does not perform any correction until the level of electrical energy is sufficient for a complete correction. 2) The timepiece has a transmitter, in particular a BLE 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 phone 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) 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) 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 management of the electrical energy as indicated above, the timepiece can start a required correction operation if the available electrical voltage is sufficient and perform this correction operation as long as the electric voltage supplied by the supply circuit 58 is sufficient. In an advantageous variant, provision is made to put the correction device in a standby mode when no operation to correct the displayed time is provided, so as to save the electrical energy available in the accumulator 56. Various parts of the correction module can be activated, as needed, only during different periods.

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 overall temporal error TErrdetermined during the preceding 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 FSUP (the generator device 62 is also called a 'frequency generator' or simply 'generator' at the frequency FSUP). Depending on whether the overall time error TErr to be corrected corresponds to a delay (TErrnégatif) or to an advance (TErrpositif) in the display of the real time, the control logic circuit 60 generates respectively either two control signals S1R and S2R, which 'it supplies respectively to the frequency generator 62 and to a time counter 63 (' timer '), that is to say a control signal SA which it supplies to a time counter 70. The time counters 63 and 70 are programmable and are used to measure a period correction period, respectively a period PRcor for the correction of a delay and a period PACorfor 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 delay detected in the time display 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, it is planned, according to a first mode of correcting a delay, to generate a series of periodic braking pulses at a frequency FSUP, these pulses periodic braking being applied by the braking device 22, in particular by the actuator 22A to the oscillating resonator. To do this, the control logic circuit 60 activates the frequency generator 62 via the signal S1R and the time counter 63 which counts or counts down a time interval corresponding to a correction period PRCord the duration (the value) is determined by the circuit logical (by definition, the expression 'time counter' includes a time counter at a given time interval and also a time count down to zero from this given time interval which is initially introduced into this time count down).

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

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

According to the teaching given by document WO 2018/177779 already cited above, it is possible to precisely regulate the average frequency of an oscillating resonator by continuously applying periodic braking pulses to it at a corresponding braking frequency FFR advantageously twice the reference frequency FOc divided by a positive integer N, i.e. FFR = 2 · F0C / N. The braking frequency FFR is proportional to the reference frequency FOc for the mechanical resonator and depends only on this reference frequency as soon as the positive integer N is given. We learn from document WO 2018/177779 that, after a transient phase occurring at the start of the activation of the braking device applying the periodic braking pulses to the braking frequency FFR, a synchronous phase is established during which the oscillation of the brake. The mechanical resonator is synchronized, on average, on the setpoint frequency F0C, provided that the braking torque applied by the braking pulses and the duration of these braking pulses are selected so that the braking pulses intervene, during the synchronous phase, when the mechanical resonator passes through extreme positions of its oscillation, i.e. the reversal of the direction of the oscillation movement occurs during each braking pulse or at the end of each braking pulse. This latter situation occurs in the advantageous, in particular safer, case where the mechanical resonator is stopped by each braking pulse and then remains blocked by the braking device until the end of this braking pulse.

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

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

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

Thus, the periodic braking pulses are applied to the mechanical resonator at a braking frequency FBrac advantageously corresponding to twice the correction frequency FCordivised by a positive integer N, preferably not very high. This relation is valid for a correction frequency FCor = FSCor which is greater than the reference frequency and also for a correction frequency FCor = FlCor which is less than the reference frequency (first mode of correction of an advance which will occur thereafter in another embodiment of a timepiece according to the invention). The braking frequency FBra is therefore proportional to the planned correction frequency Fcor 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 braking frequency FBra = 2 · FCor / N makes it possible to obtain synchronization on the frequency Fcor more efficiently and with more stability. In general, the mathematical relationship between the braking frequency and the correction frequency is FBra = (p / q) · FCor with p and q two positive integers and the number q advantageously greater than the number p. The person skilled in the art can experimentally establish a list of the fractional numbers p / q which are appropriate and under which conditions (in particular for which braking torque).

It will be noted that the braking pulses can be applied with a constant 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 TOc / 8 .

Figures 8 and 9 are shown, for a mechanical resonator having a setpoint frequency FOc = 4 Hz and having an oscillation 72, respectively a first series of periodic braking pulses 74 applied to the resonator at a frequency FINF = 2 · FICoravec FICor = 0.99975 · F0c = 3.999 Hz, for the case of a natural frequency FO = 4.0005 Hz, and a second series of periodic braking pulses 76 applied to the resonator at a frequency FSUP = 2-FScor with FSCor = 1.00025 · F0c = 4.001 Hz, for the case of a natural frequency F0 = 3.9995 Hz. The lower graphs in Figures 8, 9 show the evolution of the oscillation frequency of the resonator during a correction period, which is defined as the period during which the braking pulses at the frequency FINFor FSUP are applied to the resonator. Curve 78 shows the evolution of the oscillation frequency of the mechanical resonator during the application of the first series of periodic braking pulses 74 for a correction of an advance detected in the displayed time, the braking frequency FINF leading to a correction frequency FlCor, given by the synchronization frequency, which is lower than the reference frequency F0c (first mode of correction of an advance). Curve 80 shows the evolution of the oscillation frequency of the mechanical resonator during the application of the second series of periodic braking pulses 76 for a correction of a delay detected in the displayed time, the braking frequency FSUP leading to a correction frequency FSCor, given by the synchronization frequency, which is greater than the reference frequency (first mode of correction of a delay).

The very short correction period in 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 in 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 approximately 10 seconds per day (advance, respectively delay), the frequencies of correction are given purely by way of example and are much closer to the reference frequency than the correction frequencies which are generally provided for the implementation of the first mode of correcting an advance or a delay. In conclusion, Figures 8 and 9 are given only schematically to show in general the behavior of the oscillating resonator when subjected to a series of periodic braking pulses at a correction frequency close to the setpoint frequency, but different of the latter, and in the case of a natural frequency leading to a classical time drift. More detailed and precise considerations relative to the possible correction frequencies will be explained below.

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

The duration of the transient phase and the evolution of the frequency during this transient phase depend on various factors, in particular the braking torque, the duration of the pulses, the initial amplitude of the oscillation, and the instant at which the first braking pulse occurs in an oscillation period. It is therefore difficult to control the time difference resulting from a transient phase relative to the reference frequency. As an example, if FCor = 1.05F0C = 4.2 Hz and the transition phase lasts a maximum of 10 seconds, and if we assume that the average frequency during this transition phase is equal to F0c , then the absolute time deviation from FCor is a maximum of half a second. This uncertainty therefore generates a small error in the correction generated during a correction period, but it is not negligible. We will see below a solution to avoid such an error. In the first embodiment of the electronic control unit, there is therefore a small possible error in the correction obtained if we determine (the duration of) the correction period PRConly on the basis of the overall time error TErr to be corrected, by defining this correction period as being the period during which a series of periodic braking pulses are applied to the resonator at the expected braking frequency, and assuming that the oscillation frequency during the period of correction is that of the synchronization frequency.

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

Starting from the hypothesis mentioned above, namely that the synchronization frequency occurs over the entire correction period PRcor, it is possible to determine the value of the correction period to be provided on the basis of the time error global TErrà to correct, of the reference frequency F0c and of the correction frequency FCor; and as the synchronization frequency determines the correction frequency which is equal to it, it is also possible to determine the value of the correction period to be provided on the basis of the overall time error TErr to be corrected, of the reference frequency F0c and of the braking frequency FBra. 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: PCor = TErrF0c / (F0c - FCor) = 2TErrF0c / (2F0c - NFBra)

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

In the first mode of correction of an advance (positive error), the correction frequency FCor = FlCorest less than F0c, so that PCor is quite positive. In this case the braking frequency FBra = FINF. We then have the relation: PAcor = TErr <> F0c / (F0c - FICor) = 2TErr F0c / (2F0c N FINF)

Following the general discussion relating to a correction of the rate of a mechanical timepiece obtained by a series of periodic braking pulses applied to its resonator, one can return to the first embodiment of the part clockwork according to the invention. The control unit 48A (Figure 7) is arranged to supply to the braking device, each time the overall time error TErr corresponds to a delay in the displayed time which it is intended to correct, a control signal SC1 derived from the periodic digital signal SFS supplied by the frequency generator 62, during a correction period PRCor, to activate the braking device 22 so that this braking device generates a series of periodic braking pulses which are applied to the resonator at the frequency FSUP . Since (the duration of) the correction period is determined by the delay to be corrected, the number of periodic braking pulses in the series of periodic braking pulses is therefore also determined by the delay to be corrected. The frequency FSUP is provided and the braking device is arranged so that each series of periodic braking pulses at the frequency FSUP can generate, during the corresponding correction period, a first synchronous phase in which the oscillation of the resonator is synchronized. (by definition "synchronized on average") on a correction frequency FScor which is greater than the reference frequency F0c provided for the mechanical resonator.

With reference to Figures 10 to 13B, a few observations relating to the braking pulses will be set out below, in particular concerning the braking frequencies FBraet the corresponding correction frequencies FCor which are advantageously envisaged in a preferred variant of the first correction mode d. '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 an advance detected in the displayed time by a series of braking pulses at a frequency FINF, already defined previously, resulting in a correction frequency FlCor, also defined previously, which is lower than the reference frequency F0c.

FIG. 10 shows a first part of a correction period with a relatively high ratio between the correction frequency FSCor = 3.5 Hz and the reference frequency F0c = 3.0 Hz (substantially equal to the natural frequency of the resonator when it oscillates freely, represented by the oscillation 82), namely a ratio RS = FSCor / F0c = 3.5 / 3.0 = 1.167. When applying to the mechanical resonator braking pulses 84 with a braking frequency FBra = FSUP = 2-FScor = 7.0 Hz (case N = 1) and a sufficient braking force torque, allowing in the transient phase PHTrde sufficiently reduce the amplitude of the oscillation 86 of the oscillating resonator to finally stop it during each braking pulse, one can impose on this resonator relatively quickly the corresponding correction frequency, that is FSCor = 3.5 Hz. that already after one second the desired synchronization is obtained in the example given, but a phase PHSt of stabilization of the oscillation occurs at the start of the synchronous phase PHSyn. In the case shown, the amplitude increases again during the stabilization phase to finally stabilize at an amplitude corresponding to approximately one third of the initial amplitude of the free resonator.

A demonstrator (a prototype of the timepiece according to the invention) was produced for the case presented in FIG. 10. By applying periodic braking pulses at the frequency FSUP = 7.0 Hz to the mechanical resonator , we obtained a lead of 7 hours on the display of the timepiece for a correction period of 6 hours, and this very precisely. We have thus '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).

[0105] FIG. 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 FSCoret the setpoint frequency F0c is relatively small (i.e. relatively close to '1'), and a second oscillation 86B of this resonator in a phase synchronous with a correction period where the ratio RS between the correction frequency FSCor and the frequency setpoint F0c is relatively high (that is to say relatively far from '1'). The first oscillation 86A results from a series of periodic braking pulses 84A of relatively low intensity and occurring once per oscillation period (which corresponds to the case N = 2 with FSUP = FSCor). On the other hand, the second oscillation 86B results from a series of periodic braking pulses 84B of relatively high intensity and occurring once per alternation of the oscillation (which corresponds to the case N = 1, i.e. FSUP = 2 · FSCor) .

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

[0107] In Figure 11 is indicated a safety angle θSec below which, in absolute value, one will avoid stopping the mechanical resonator (that is to say between -θSecet θSec), and therefore above which the amplitude, in absolute value, must practically remain during the synchronous phase, at least after the stabilization phase. Advantageously for the operation of the mechanical resonator, the angle θSec is expected to be equal to or, preferably, greater than an angle θZI (see Figure 14) which corresponds to the angle of coupling between the resonator and the exhaust associated with it. , on one side and on the other side of the neutral position of the resonator defined by the angular position of the coupling pin carried by the balance plate when this resonator is at or passing through its rest position. In order to stop the mechanical resonator during a braking pulse, the angular coupling zone (-θZI to θZI) between the mechanical resonator and the escapement is thus declared 'prohibited zone' (it will be noted that it is possible to brake in this prohibited zone during the transitional phase, but avoid stopping the resonator in this prohibited zone). It will be noted that, in the useful operating range of the resonator, it may be necessary, in order to maintain correct operation of the escapement and in particular to ensure the release phase, that the safety angle θSec be greater than the coupling angle. θZI. The person skilled in the art will know how to determine a value for the safety angle θSec for each mechanical movement associated with a correction device according to the first embodiment. The coupling angle θZI can vary from one mechanical movement to another, in particular between 22 ° and 28 °.

[0108] 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 (that is to say the timing time display drive mechanism) must continue during this delay correction period. Thus, very advantageously, said frequency FSUP and the duration of the periodic braking pulses are selected so that, during said synchronous phase of a correction period in the context of the first mode for correcting a delay, the periodic braking pulses each intervene outside a coupling zone between the oscillating mechanical resonator and the escapement, preferably outside a defined safety zone for the mechanical movement. The same applies to the selection of said frequency FINF and the duration of the periodic braking pulses within the framework of the first mode of correction of an advance.

To guide the person skilled in the art in the choice of the correction frequencies and the corresponding braking frequencies, a mathematical model has been established on the basis of the equation of motion of a mechanical oscillator. To determine a maximum correction, positive or negative, we consider the resonator in a synchronous and stable phase. Then, a simplification is introduced for the sustaining force applied to the resonator by the energy source via the exhaust, considering it of the cos (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 θZIdefined previously. Finally, we consider the duration of the braking pulses very small, in fact punctual, by defining the braking frequency FBracas the inverse of the time value TSec at which the resonator reaches, in the equation of motion given below, the safety angle θSec in the half-wave corresponding to the number N selected in the relation FCor = N · FBra / 2.

[0110] To find the maximum correction and therefore the minimum or maximum period depending on whether the time error to be corrected is negative (delay) or positive (advance), the time t = 0 is given by a braking pulse during which the oscillator is stopped at the safety angle θSec. Then, in the stable synchronous phase, the resonator must stop at the next braking pulse at the earliest, respectively at the latest also at the safety angle (-1 <N>) θSec within a time range given by the value of N and by the fact that the correction frequency is expected to be greater or less than the reference frequency F0c to correct the delay or advance.

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

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

To obtain a correction frequency FScor 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:

[0114] The maximum braking frequency FSBmax (N) = 1 / TSec and the maximum correction frequency FSCmax (N) = N · FSBmax / 2.

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

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

[0117] Figures 12A and 12B respectively represent the curves of RSmax (N = 1) = FSCmax (N = 1) / F0c and of RSmax (N = 2) = FSCmax (N = 2) / F0c as a function of the amplitude θ0 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 ratio RSmax (N).

[0118] Figure 13A gives, for a resonator having a quality factor Q = 100, a free amplitude θ0 = 300 ° and a safety angle θSec = 25 °, the higher correction frequency ranges, for a setpoint frequency F0c and various respective values of N, which can be envisaged in the context of the first mode of correction of a delay, by representing the ratio RS = FSCor / F0c which extends between the value '1' and RSmax (N).

[0119] Figure 13B gives, for a resonator having a quality factor Q = 100, a free amplitude θ0 = 300 ° and a safety angle θSec = 25 °, the lower correction frequency ranges, for a setpoint frequency F0c and various respective values of N, which can be envisaged within the framework of the first mode of correction of an advance, by representing the ratio RI = FICor / F0c which extends between RImax (N) and the value '1'.

[0120] As indicated above, the ranges given in Figures 13A and 13B result from a simplified theoretical model. It can be seen that the maximum and respectively minimum correction frequencies depend on several parameters. These figures give a good indication of the reality for a mechanical movement having fairly standard properties. However, for each given mechanical movement, it will be necessary to define the limit values if one wishes to approach them in order to make large corrections in relatively short correction periods.

After having explained in detail the arrangement of the control unit and the operation of the correction device of the first embodiment of the timepiece according to the invention to correct a delay in the time displayed by the timepiece, the arrangement of the 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 correction of 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 serves also to the implementation of the first mode of correction of a delay. When the overall time error TErr 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 SA to the time counter 70 (timer) which is programmable. This timer 70 then generates a signal SC2 for activating the braking device 22, via the 'OR' ('OR') gate 66 or another switch, for a correction period PAC, the duration of which is substantially equal to the corresponding advance TErrà. to correct. The periodic activation signal SC2 then forms the control signal SCmd. It will be noted that the activation signal SC2 controls the braking device 22 in a mode of blocking the mechanical resonator for a relatively long period, namely during substantially the entire correction period PACor = TErr. To this end, the voltage then supplied by the supply circuit 26 between the two electrodes of the piezoelectric blade 24 may differ from that provided to generate the periodic braking pulses to correct a delay. This voltage is selected so that the braking force applied to the mechanical resonator can stop it, preferably quite quickly, and then block it until the end of the correction period.

[0124] 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 (-θZI to θZI) defined above. For this purpose, the braking torque is selected large enough to be able to stop the resonator and lock it in the angular stop position, whatever it may be, and small enough so that this braking torque cannot stop the resonator in the forbidden angular zone. Preferably, one will avoid stopping the resonator in the angular safety zone (-θSecà θSec), described previously. This last condition is important when the resonator is not self-starting. In general, it suffices to ensure that the resonator can start again at the end of the correction period.

[0125] According to a specific variant making it possible to ensure rapid stopping of the resonator outside the above-mentioned angular safety zone, a preliminary phase occurring before the correction period when the resonator is blocked (that is to say where it remains stopped following its stop intervening quickly or immediately at the start of the correction period). During the preliminary phase, provision is made to use the first mode of correction of a delay available in the first embodiment. It can be seen that in the synchronous phase of the first correction mode described above, the passage through an extreme angular position occurs during each braking pulse. Thus, the braking pulses are in phase with passages of the mechanical resonator through one of its two extreme angular positions, each of these passages defining the start of an alternation. Advantage is taken of this fact by activating the frequency generator 62 during the preliminary phase, which is intended to be of relatively short duration but nevertheless of sufficient duration for the establishment of a synchronous phase where the resonator is synchronized on the frequency FScor. The preliminary phase ends, for example, with a last braking pulse which is immediately followed by the correction period with activation of the braking device in the blocking mode. Thus, it is known that the resonator is blocked outside the angular safety zone. The braking torque for the preliminary phase can be expected to be different from that used for the correction of a delay explained above.

[0126] As the behavior of the frequency during the transient phase at the start of a series of periodic braking pulses may vary from case to case, it is hardly possible to determine the error caused by the preliminary phase. . However, it is possible to estimate a maximum error. For example, if the FSUP frequency = 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), it is possible to estimate the maximum error at 0.5 seconds (half a second). For a mechanical movement, if such an error is not negligible, it is relatively small since a conventional mechanical movement has a daily error generally between 0 and 5 to 10 seconds.

With reference to 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.

[0128] The timepiece comprises a locking device 106 which is distinct from the braking device 22A (FIG. 1) used for the correction of a delay. This locking device is therefore dedicated to the implementation of the second method of correcting an advance. The locking device is formed by an electromechanical actuator, in particular by a piezoelectric actuator of the same type described in connection with Figure 1. According to the variant shown, the actuator comprises a flexible piezoelectric blade 24A and its two electrodes are supplied with voltage. by a 26A power supply circuit. The blade 24A has at its free end a projecting 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 plate has a through-hollow 108, which opens radially on the periphery of the plate and whose profile in the general plane of the plate is provided to allow the stud 107 to come to be housed there when it is located angularly in front of the plate. this hollow and that the piezoelectric actuator 106 is activated. According to the variant shown, the hollow 108 is diametrically opposed to the pin 98 and the stud is located angularly at the zero position of the pin (that is to say at the angular position of this pin when the resonator is at rest, respectively passes through its neutral position). Note that this zero angular position of the ankle normally defines the zero angular position of the balance 104, and therefore of the mechanical resonator, in a fixed angular reference relative to the mechanical movement 92 and centered on the axis of rotation of the balance.

[0129] 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.

[0130] 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 side walls, perpendicular to the general plane of the plate, which are parallel to the radius passing through its center and the axis of rotation of the balance or which are, in the equivalent variant, substantially radial relative to the rotation axis. Thanks to this arrangement, when the stud 107 is introduced into the hollow 108 which then serves as its housing, this stud blocks the rotation of the plate 100 and therefore of the balance 104 by a substantially tangential force, the direction of which is substantially parallel to the longitudinal direction. general of the piezoelectric blade 24A. When the actuator 106 is activated, the end of the blade carrying the stud 107 undergoes a substantially radial displacement, relative to the axis of rotation of the balance, and the stud can then, depending on the angular position of the balance at this moment, either exert an essentially radial force on the circular lateral surface of the plate 100, or at least partially enter the hollow 108. The actuator must only be arranged so that the stud can undergo, when this actuator is activated, a sufficient displacement to be introduced into the hollow when the latter is located in an angular position corresponding substantially to that of the stud (in a fixed angular reference relative to the stud).

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

[0132] 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 similar manner to operation of the first embodiment, activates the blocking device 106, by supplying it with a control signal SC2 similar to that described previously in the context of the first embodiment, for a period substantially equal to the 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.

[0133] Finally in connection with the second embodiment, the electromechanical actuator can be of another type than that shown in FIG. 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 the pad is at least partially entering the hollow 108. Such a This variant is particularly interesting because the actuator must not exert any blocking force by applying radial pressure on an element of the resonator balance in its two stable positions corresponding respectively to the non-interaction position and the expected interaction position. In this preferred variant, the energy consumption can be very low, regardless of the duration of the correction period, which is very advantageous.

With reference to Figure 15, a third embodiment of a timepiece according to the invention will be described, which differs essentially from the first embodiment by the arrangement of the locking device making it possible to advantageously implement the second mode of correcting an advance in the time display associated with the mechanical movement of the timepiece. The references already described in relation to Figures 1 and 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 SC1, 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 side surface of the rim 20 of the resonator to generate a certain braking force. mechanical on this resonator during a braking pulse.

[0135] 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.

[0136] The blade 116 is associated with a particular magnetic system making it possible to generate the bistable nature of the latch 115 and consequently of the locking device 114. The magnetic system comprises a first magnet 118, carried by the blade and therefore integral in rotation of this blade, a second magnet 119 fixedly arranged 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, at 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 into a housing of the support 242 located in front of magnet 119).

[0137] The first and second magnets 118, 119 have magnetic polarities which are opposite and their respective magnetic axes are substantially aligned. Thus, in the absence of the ferromagnetic plate, these two magnets would constantly exert a repulsive force on each other and the rocker would remain or always return, in the absence of forces external to the magnetic system, in a position where the blade is in abutment against a pin 124 for limiting its rotation. However, thanks to the arrangement of the ferromagnetic plate, there is a reversal of the magnetic force which is exerted between the two magnets. More precisely, when approaching the mobile magnet 118 from its remote position (shown in Figure 11), the repulsive force decreases until it is canceled out and finally reversed when the mobile magnet comes close to it. the ferromagnetic plate. Thus, when the mobile magnet 118 is located very close to or against the ferromagnetic plate 120, this mobile magnet is subjected to a magnetic force of attraction. This astonishing physical phenomenon is set out in detail in patent application CH 711 889, which also contains some horological applications.

[0138] 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 from said magnetic assembly which holds the lever 115. against this serge. 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.

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 alternately switch the latch 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 actuator is controlled by the logic circuit of the control unit via its power supply circuit 254 which receives the control signal SC2. 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 flip-flop passes into its interaction position, then the power supply to the coil is cut off 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 mobile magnet which is provided sufficient to cause the latch to switch to its non-interaction position, thus ending the correction period.

[0140] In another variant, the device for actuating the latch is provided separate and independent from the magnetic system of the bistable latch. 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 blocking device. magnetic system that forms it. 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 exerting generally initially a dynamic dry friction against the outer lateral surface of the rim, when the rocker is actuated by the actuator to move from its first stable position to its second stable position at the start of a period of correction of a advance, before entering the hollow when the latter is in front of the stud during the oscillation of the balance.

With reference to Figure 16 and 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 SW-UP wake-up signal 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 method, the management circuit 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.

Given that the fourth embodiment is characterized by an implementation of the first mode of correcting a delay, as in the first embodiment, and of the first mode of correcting an advance, already described previously but not implemented in the first embodiment, any correction provided herein is accomplished by a series of periodic braking pulses during a correction period. In a main variant, all the braking pulses are provided with the same duration Tp. Thus, one and the same timer 64 is necessary to determine the duration of the braking pulses and this timer is arranged, in the variant shown in FIG. 16, in the supply circuit 26C. This timer provides an activation / actuation signal SActà a switch 138 placed between a voltage source 140 and the braking member 24C acting on the balance. The braking member 24C is for example similar to the piezoelectric blade (Figure 1) of the variant shown for the first embodiment or to 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 S1Cmd from a switching device 66A which is controlled by the logic circuit 60A so that the first control signal is selectively formed by a periodic digital signal among three periodic digital signals provided SFS, SFI and SF0c which respectively have three different frequencies FSUP, FINF and F0c. The periodic digital signal periodically resets the timer at the selected frequency and, in response, this timer periodically activates the actuator for a duration Tp, making switch 138 temporarily conductive, to generate a series of periodic braking pulses at this time. selected frequency.

When an overall 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 FSUP, a corresponding correction period PRcor or, in an equivalent manner, a number periodic braking pulses to be generated at frequency FSUP 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 at the frequency FSUP leading to a correction frequency FScor greater than the setpoint frequency, it uses the frequency generator 62, already described, which supplies a periodic digital signal SFS at the frequency FSUP to the timer 64 via the switch 66A, which is controlled for this purpose by the control logic circuit.

When an overall time 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 FINF, a corresponding correction period PAcor or a number of periodic braking pulses. to be generated at a frequency FINF, defined previously, during the current correction cycle. To do this, he uses the formula relating to this calculation which was established previously. To apply the series of braking pulses at the frequency FINF leading to a correction frequency Flcor lower than the reference frequency, it uses the frequency generator 142 which supplies a periodic digital signal SFI at the frequency FINF to the timer 64 via the switch 66A, which is controlled for this purpose by the logic control circuit.

In general, to allow the implementation of the first mode of correction of an advance, the electronic control unit 48B is arranged to be able to supply the braking device, when the correction signal SCorf supplied by the control unit. treatment corresponds to an advance in the displayed time that it is intended to correct, a control signal derived from a periodic digital signal supplied by a frequency generator at a FINF frequency, during a correction period, to activate the device braking so that it generates a series of periodic braking pulses applied to the mechanical resonator at the frequency FINF. This FINF frequency is provided and the braking device is arranged so that the series of periodic braking pulses at the FINF frequency can generate, during the correction period, a synchronous phase in which the oscillation of the mechanical resonator is synchronized with a correction frequency FICorqui 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.

[0150] The correction device of the fourth embodiment comprises an improvement to increase the precision of the correction carried out and also to allow the application of relatively high braking torques, in particular for corrections at frequencies relatively far from the reference frequency. , without running the risk of permanently stopping the mechanical resonator by stopping, during a braking pulse at the start of the correction period, in the angular coupling zone between the resonator and the escapement or more generally in the angular zone of security described previously. According to this improvement, the timepiece comprises a device for determining the passage of the oscillating mechanical resonator through at least one specific position, this device for determining a specific position of the mechanical resonator allowing the electronic control unit to determine a specific instant at which the oscillating mechanical resonator is in said specific position, and therefore to determine the phase of the resonator. Then, the electronic control unit is arranged so that a first activation of the braking device occurring at the start of the correction period, to generate a first interaction between this braking device and the mechanical resonator, is triggered as a function of said specific moment.

[0151] According to an advantageous variant of the improvement described above and with reference to FIG. 16, the correction device further comprises a frequency generator 144 which is arranged so as to be able to generate a periodic digital signal SF0c at the setpoint frequency. F0c provided for the resonator. The control unit 48B is arranged to be able to supply the braking device with a control signal derived from the periodic digital signal SF0c, during a preliminary period directly preceding the correction period, to activate the braking device so that this braking device 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 SPP. The duration Tp of the periodic braking pulses and the braking force applied to the oscillating resonator, during the preliminary series of periodic braking pulses, are provided so that none of these braking pulses can stop the oscillating resonator in the coupling zone of this oscillating resonator with the escapement which is associated with it (between - θZI and θZI) or, preferably, in a predefined safety zone (between - θSecet θSec) including the coupling zone (these zones have been explained previously ).

Then, the duration of the preliminary period and the braking force applied to the oscillating resonator, during the preliminary series of periodic braking pulses, are provided so as to generate at least at the end of the preliminary period a synchronous phase preliminary in which the oscillation of the mechanical resonator is synchronized (on average) on the reference frequency F0c. In the variant shown, the electric voltage source 140 is variable and controlled by the logic circuit 60A which supplies it with a control signal S2Cmd, so that the voltage level applied to the braking member 24C can be varied to vary the braking force. It is thus possible to provide a lower braking force during the preliminary period than during a correction period which follows it. The braking force can also be varied during the preliminary period and / or the correction period. 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, provided for correcting an advance or a delay, directly follows the preliminary period. More precisely, the triggering of a first braking pulse at the frequency FINFor FSUP, at the start of a period for correcting the displayed time, occurs after a determined time interval relative to an instant at which the last pulse of braking of the preliminary period, so that this first braking pulse occurs outside a predefined safety zone including the aforementioned coupling zone. This condition is easily fulfilled by the fact that the resonator is in a synchronous phase at least at the end of the preliminary period; which has the consequence that the resonator stops during the last braking pulse of this preliminary period. Thus, a reversal of the direction of rotation occurs during said last braking pulse, so that the start of a new alternation of the oscillation of the resonator occurs during this last braking pulse. The correction device can thus know, with an accuracy of Tp / 2 (for example an accuracy of 3 ms), the phase of the oscillation. Therefore, the electronic control unit can be arranged so that the control logic circuit can determine an initial time to trigger the first braking pulse which fulfills the aforementioned condition, by activating the frequency generator 62 or 142, depending on the requirement. correction required, after a determined time interval since said last braking pulse which ensures that the first braking pulse is outside the predefined safety zone.

In addition, the instant of triggering of said first braking pulse and the braking force applied to the oscillating resonator, during this first pulse and then during the periodic braking pulses which follow during the correction period, are provided in such a way that the phase synchronous with the correction frequency FICor or FSCo 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 achieving stop the resonator, and that this synchronous phase remains throughout the correction period. In a particular variant, the first braking pulse of the correction period occurs after a time interval corresponding to the inverse of the frequency FSUP or FINF, depending on the correction required, following the instant at which the last braking pulse of the preliminary period. In another particular variant, said time interval is selected equal to the inverse of double the correction frequency FSCor or FICor, depending on the correction required, or to the inverse of this frequency FSCor or FICor. 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). Note that the generators at the various frequencies have been shown separately in Figure 12, but only one programmable frequency generator device can be used.

With reference to Figures 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.

[0156] The timepiece 170 according to the fifth embodiment is shown in part in 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 reflection coefficients different from the light coming from an optical sensor 192 or simply a different reflection of this light, in particular a succession of at least two black bars of different widths and separated by a white bar, the width of one of the two black bars being equal to the sum of the widths of the other black bar with the white bar. It will be understood that the bars thus form a sort of code with a transition in the middle of the mark 191. Instead of black bars and a white bar, other colors can be taken. In a variant, the black bars correspond to matt areas of the serge, while the white bar corresponds to a polished area of this serge. The black bars can also correspond to notches in the serge which present an inclined plane. Several variants are therefore possible. Note that the mark 191 has been shown on the top of the rim for its description, but in the variant shown it is located on the outer lateral surface of the rim since the optical sensor is arranged in the general plane of the balance 16A . In another variant, the mark is located as shown, on the upper or lower surface of the rim, and the sensor is then rotated by 90 ° in order to be able to illuminate this mark.

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

Next, the timepiece 170 comprises a resonator braking device which is formed by an electromechanical device 174 with a bistable movable stop. An alternative embodiment, by way of non-limiting example, is shown in FIG. 17. The electromechanical device 174 comprises an electromechanical motor 176, of the watchmaking stepper motor type of small dimensions, which is supplied by a circuit d. 'power supply 178, which comprises a control circuit arranged to generate, when it receives a control signal S4Cmd, a series of three electrical pulses which are supplied to the coil of the motor so that its rotor 177 advances one step at a time. each electrical impulse, or half a turn of rotation. The series of three electrical pulses is designed to drive the rotor rapidly, continuously or almost continuously. The rotor pinion meshes with an intermediate wheel 180 which meshes with a wheel having a diameter equal to three times that of the rotor pinion and fixedly bearing a first bipolar permanent magnet 182. Given the diameter ratio between said pinion and the bearing wheel the magnet 182, the latter turns half a turn during a series of three electrical pulses. Thus the first magnet has a first rest position and a second rest position in which the first magnet has a magnetic polarity opposite to that of the first rest position (by 'rest position' is understood a position in which is found magnet 182 after motor 176 has made a series of three electrical pulses on command and its rotor has then ceased to rotate).

[0160] In addition, the actuator 174 comprises a bistable rocker 184 pivoted about an axis 185 fixed to the mechanical movement and limited in its rotation by two pins 188 and 189. The bistable rocker comprises at its free end, forming the head of this rocker, a second bipolar permanent magnet 186 which is movable and substantially aligned with the first magnet 182, the magnetic axes of these two magnets being provided substantially collinear when the first magnet is in one or the other of its two rest positions. Thus, the first rest position of the first magnet corresponds, relative to the second magnet 186, to a position of magnetic attraction, and its second position of rest corresponds to a position of magnetic repulsion. Each time the control signal S4Cm activates the power supply circuit to perform a series of three electrical pulses, the first magnet turns half a turn and the rocker alternately passes from a stable position of no interaction with the balance of the resonator in a stable position of interaction with this balance in which the rocker 184 then forms a stop for the projecting part 190, which abuts against the head of this rocker when the resonator oscillates and the projecting part reaches the level of this head, whatever the direction of rotation of the balance during the impact.

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

[0162] The stop member in its interaction position and the protruding part define a first angular stop position θB for the balance of the oscillating resonator which is different from its neutral position, the protruding part abutting against the stop member at this first angular stop position when it arrives from its angular position '0', corresponding to the neutral position of the resonator, during a second half-wave of a first determined alternation among the two half-waves of each period d oscillation of the resonator. Then, the angle θB is expected to be less than a minimum amplitude of the oscillating mechanical resonator in its useful operating range. In addition, the angle θB is provided so that the oscillating resonator is stopped by the stop member outside the zone of coupling of the oscillating resonator with the escapement of the mechanical movement, which has already been described. The stop member in its interacting position and the protruding part also define a second angular stop position, close to the first but greater than the first, for the balance of the oscillating resonator when the protruding part arrives from an angular position extreme of the resonator during a first half-cycle of the second one of the two half-cycles of each period of oscillation. This second angular stop position is also provided less than a minimum amplitude of the mechanical resonator oscillating in its useful operating range.

[0163] 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.

[0164] Finally, the timepiece 170 comprises a control unit 196 which is associated with the optical sensor 192 and arranged to control the power supply circuit 178 of the electromechanical device, to which the control unit supplies the control signal S4Cmd . 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 bistable rocker 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 non-interaction position at its interaction position respectively before the protruding portion 190 reaches said first angular stop position θB during said second half-wave of said first alternation of an oscillation period and before the portion protrusion 190 does not reach said second angular stop position during said first half-cycle of said second half-cycle of an oscillation period.

In general, to correct at least in part an advance (positive time error), the electromechanical device is arranged so that, when the stop member is actuated to stop the mechanical resonator in a first half-wave, the stop member momentarily prevents, after the projecting part has butted against this stop member, the mechanical resonator from continuing the natural oscillation movement specific to this first half-wave, so that this natural oscillation movement at the The course of the first half-cycle is momentarily interrupted before it is continued, after a certain blocking period which ends with the withdrawal of the stop member. Preferably, in the case of a bistable electromechanical device as described above, provision is made to correct substantially the whole of a positive 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 T0c / 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, to correct at least in part a delay (negative time error), the electromechanical device is arranged so that, when the stop member is actuated to stop the mechanical resonator in a second half-wave of 'at least one said first alternation of a period of oscillation (alternation during which the projecting part 190 arrives at the level of the head of the rocker 184 after the passage of the resonator through its neutral position), it thus terminates prematurely to this second half-wave without blocking the resonator but by reversing the direction of the oscillation movement of this resonator, so that the mechanical resonator begins, following an instantaneous or almost instantaneous stop caused by the collision of the projecting part with the organ of stop, directly a following alternation. Thus, in the context of the second mode of correcting a delay, the position detector and the direction of movement of the resonator and the electronic control unit are arranged so as to be able to activate the actuator, each time the 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, to at least partially correct a delay, the latch is maintained in its interaction position, following an actuation of this rocker from its non-interaction position to its interaction position while the oscillating resonator is located angularly on the side of its neutral position relative to the angular stop position, until the end of the period of correction during which the protruding part of the oscillating mechanical resonator periodically abuts the head of the rocker several times, the (duration of the) correction period during which the rocker is kept in its interaction position being determined by the delay to correct. The pivoting of the rocker from its non-interaction position to its interaction position can take place either in a so-called first alternation (that in which the impact with the projecting part is provided, this first alternation being detected by the detection of the direction of rotation of the balance) preferably directly after the detection of the passage through the neutral position so that the rocker is placed in its interaction position before the projecting part reaches the stop angle θB, or in a so-called second alternation (also detected by detecting the direction of rotation of the balance) directly after the detection of passage through the neutral position, this second variant leaving more time to actuate the rocker and allow it to be placed in a stable manner in its interaction position (l the stop angle is by definition less than or equal to 180 °). For example, if θB = 120 ° and the amplitude of the free oscillation of the resonator θL = 270 °, then we have in the second variant a time interval corresponding to a rotation between the angle '0' and a slightly less than 240 ° (360 ° -120 °), i.e. approximately 230 ° if the angle θT to the axis of rotation defined by the head of the rocker is approximately 10 °, to perform the pivoting of the rocker (so as to do not block the balance by going beyond the position of the projecting part in the second cycle); whereas in the first variant there is only one time interval corresponding to a rotation between the angle '0' and 120 °. Note that if θL <360 ° - θB- θT, then we have much more time in the second variant to perform the pivoting of the rocker.

In general, to determine the duration of a delay correction period, the control unit comprises a measuring circuit associated with the optical sensor, this measuring circuit comprising a clock circuit, providing a clock signal at a determined frequency, and a comparator circuit making it possible to measure a time drift of the oscillating resonator relative to its reference frequency, the measuring circuit being arranged to be able to measure a time interval corresponding to a time drift of the mechanical resonator since the start of the correction period. The control unit is arranged to end 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 FIG. 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 number MCb) 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 whole number MCb corresponds to the number of additional alternations performed by the resonator, from an initial instant when the reversible counter is reset, relative to a case of an oscillation at the setpoint frequency.

The logic control circuit 198 receives from the optical sensor 192 a digital signal allowing this logic circuit to determine the passages of the resonator by its neutral position and the direction of the oscillation movement at each of these passages. To correct a given delay, following a detection of a passage of the resonator through its neutral position as described above, the control logic circuit, on the one hand, activates the actuator 174 so that it actuates the rocker towards its interaction position and, on the other hand, resets (performs a 'reset') the 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 latch, 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 TErr (determined delay) is equal to -TErr · 2 · F0c. Thus, as soon as the number MCbd of the bidirectional counter reaches this value or exceeds it slightly (because this value is not in all cases an integer), the determined delay is made up and the time display is correct again. (it then gives the real time precisely, in particular with a precision of one second). The logic control circuit is therefore designed to be able to compare the state of the counter with the value -TErr 2 F0c, and to end the correction period as soon as it detects that the number MCb is equal to or greater than this value. , by controlling the supply circuit 178 of the actuator so that the latter actuates the rocker from its stable interaction position to its stable non-interaction position.

In Figures 18 and 19 are shown the oscillations of the resonator 14A, respectively in two extreme particular cases of the preferred variant described above, at the start of a period for correcting a given delay. FIG. 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 alternation A2L before a detection of a time t0 when the resonator passes through its neutral position (position '0' of the projecting part 190) in the first alternation which follows, the time t0 marking the start of 'a correction period for a given delay. The latch is moved into its interaction position directly after time t0. Following the first shock between the projecting part and the latch, a relatively large positive phase shift DP1 is obtained between the fictitious free oscillation 211 and the oscillation 212. Then a stable phase is established where the oscillation 212 is abbreviated, relatively to a fictitious free oscillation 213 since the previous stop of the resonator by the stop member, in the second half-cycle of the first half-wave A1 of each oscillation period; which then results in a positive phase shift DP2 smaller than DP1. The second half-wave A2 of oscillation 212 is not disturbed by the latch.

[0174] Figure 19 relates to a particular case of a hard shock or elastic shock between the projecting part and the head of the lever. In this case the kinetic energy of the resonator is conserved at each impact, given that there is no dissipation of kinetic energy during the shocks, but only a reversal of the direction of the oscillation movement. The amplitude of the oscillation 216 during the correction period thus remains identical to that of the free oscillation 210, and therefore of the fictitious free oscillation 217 for each period of oscillation. Following time t0s, a stable phase is established with alternations A1 * and A2 * of duration T2 much less than T0 / 2, generating a relatively large positive phase shift DP3 at each oscillation period.

To obtain an elastic shock, provision can be made for the lever to have a certain elasticity, in particular for the body of the lever and / or its head to be formed of an elastic material capable of undergoing a certain compression, so as to absorb momentarily of the kinetic energy of the balance to restore it immediately after the reversal of the direction of the oscillation movement. In this case, the oscillation 216 will slightly exceed the stop angle θB. In another more sophisticated variant, it is the projecting part which is elastically mounted on the rim of the balance. For example, the protruding part has a base forming a slide arranged in a circular slide machined in the rim and an elastic element, in particular a small coil spring is arranged in the slide at the rear of the slide, that is to say. say the other side of the rocker head relative to the protrusion when it is in its angular '0' position. In practice, the 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.

[0176] In another embodiment, the electromechanical device is formed by a monostable electromechanical actuator which comprises a movable finger arranged so that this movable finger can be moved alternately between a first radial position and a second radial position when this actuator is respectively not activated (not supplied) and activated (i.e. it is supplied). The first radial position of the finger corresponds to a position of non-interaction with the balance of the oscillating resonator and its second radial position corresponds to a position of interaction with the oscillating balance in which this finger then forms a stop for the projecting part of the oscillating balance. , similarly to the head of the rocker 184.

[0177] In a general preferred 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 allowing the electronic correction circuit to determine an overall time error, and the braking device is then activated to correct, during a correction period, at least a major part of this overall time error.

[0178] 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 document WO 2018/177779 already cited above. 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 document WO 2018/177779 with the correction device according to the present invention (using the mechanical braking device and the clock circuit in common), it is possible to limit the frequency at which the correction device must be activated, which can surprisingly lead to a decrease in electricity consumption despite the fact that the regulator is still active.

[0179] 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 not to exceed one minute of error). . 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 material resources), it is possible to envisage automatically activating the correction device only once a month, or even less often, as long as the mechanical movement operates without stop. 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.

[0180] 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 for correcting, during a correction period, at least the major part of this overall temporal 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 actual time of the 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.

[0181] With reference to Figures 20 to 24, a second embodiment of the detection device which is arranged in a timepiece 260 so as to be able to perform indirect detection of the passage of at least one indicator will be described below. of the display by at least one corresponding reference time position. 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 respectively driven or driven. 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.

[0182] In Figures 20 and 21 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 a specific reference axis 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 which is formed by 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.

[0184] The processing unit 46 (Figure 1) determines the reference axis AR on the basis of a series of measurements at a given measurement frequency FM, similarly to the determination of 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 source light 278 and a photosensitive detector 276 aligned in a radial direction 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 TX0 of the seconds hand through 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.

[0185] In Figures 22 to 24 is shown an advantageous system for detecting the passage of the minute indicator through at least one reference time position of the display of timepiece 260. This detection device is formed by 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. In FIG. 22 is also referenced the barrel 292 which drives the center wheel 290. In another variant, the detection device comprises only a single detection unit.

[0186] 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 given reference temporal position is thus 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 in rotation 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 A1S1, A2S1 and A3S1. 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 (α = 360 ° / 3 = 120 ° with the gear ratio selected in the variant described). In the variant described, the detection module is further 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 A1S2, A2S2 and A3S2 which are different of the reference axes of the first series. Two adjacent angular positions of the second series having between them an angle at the center of the same value as the angle a, ie 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.

[0189] 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 reference time position 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 a single and same second reference time position, different from the first reference time position, with the minutes indicator during the detection of any angular position / any reference axis of the second series. Thus, the electronic correction circuit can determine a second moment of passage TY0 of the minute indicator through a reference time position Y0 (any one of the two reference time positions provided in the variant described) unambiguously.

[0190] 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 a greater integer S at 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 whose 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)

1. 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 reference time composed of at least one current reference time unit corresponding to said current time unit 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 by any reference temporal position of said at least one reference temporal position; in that the electronic correction circuit is arranged 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 said plurality of measurement values and a corresponding measurement instant 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 circuit electronic correction is furthermore arranged to be able to determine a temporal error of said indicator, in arant said at least one instant of passage with said reference temporal position, and an overall temporal error (TErr) for said set of indicators of the display as a function at least of said temporal error of said indicator; andin thatthe 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, according to 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. 2. 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 time base internal (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. 3. 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 in which 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 thatthe detection device (30) is arranged 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 one second reference time position of this display; when 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 in operation and clocked by the oscillating mechanical resonator (14), at least one passage of the seconds indicator through any first reference time position of said at least one first reference position and at least one passage of the minutes 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 (TErr) for the display (12) as a function of said first time error and of said second time error. 4. 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 integer number of minutes and a part. fractional 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 set the time said display; and in that the electronic correction circuit is arranged to be able to determine said overall time error (TErr) for said display further as a function of at least one predefined correction criterion for the seconds indicator and / or the seconds indicator. minutes. 5. 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. 6. 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, 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 said fractional part of the current minute displayed. 7. 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 (48; 48A; 48B). 8. 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 FSMeset the passage of the minute indicator (34M) by said at least one second reference time position with a second measurement frequency FMMes which is lower than the first measurement frequency. 9. Timepiece according to claim 8, characterized in that the first measurement frequency FSMesest provided less than three times a setpoint frequency for said mechanical resonator and greater than or equal to 1 Hz, ie 1Hz <= FSMes <3 · F0c, while the second FMMes measurement frequency is expected to be less than or equal to 118 Hz (FMMes <= 118 Hz). 10. Timepiece according to claim 8 or 9, characterized in that said first measurement frequency FSMesa a value different from twice the reference frequency F0c divided by a positive integer N, or FSMes ≠ 2 · F0c / N . 11. 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 for 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. 12. 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. 13. 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 reference time position, this indicator being designed to be able to be detected itself by the detection device. 14. 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 a photosensitive detector (227) each capable of picking 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 during passages of this indicator 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 through any reference time position of said at least one reference time position, incident light, supplied by a light source of said at least one light source, to less partially towards a respective photosensitive detector of said at least one photosensitive detector. 15. 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. 16. 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. 17. 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 an indirect detection of said passage of said indicator of the display by said au 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 mechanism d 'drive or complementary thereto, which drives or is driven by the wheel integral with the indicator; and in that the sensing wheel (294), if present, is selected or configured 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. 18. 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. 19. 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 having between them an angle at the center equal to 360 ° / R. 20. 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 positions. angular of the first series, two adjacent angular positions of the second series having between them an angle at the center 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, 21. 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 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 units of detection 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 SK. 22. 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 approximately equal to 360 ° / (R · S · K). 23. Timepiece according to any one of claims 19 to 22, characterized in that it comprises a plate (272) which upperly supports the timer wheel (294) and which carries the detection unit, which is arranged in - below the timer wheel. 24. 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. 25. Timepiece according to any one of the preceding claims, characterized in that the correction device (6; 132) is arranged so as to be activated periodically, automatically, to perform a correction cycle during which the device. detection 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 the less for the most part this overall time error. 26. 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 in such a manner. 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 braking device is activated in order then to correct, during a said correction period, at least for the most part this overall time error. 27. Timepiece according to claim 26, characterized in that said control member is formed by a crown associated with a control rod which also serve for setting the actual time of the display manually. 28. 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 'exact real time, the correction device being arranged to be able to synchronize the real reference time with an exact real time, composed of current time units of the exact real time corresponding to those of the real reference time, during a synchronization phase during which the communication unit is activated so as to receive from the external system the exact real time or said exact real time. 29. Timepiece according to claim 28, characterized in that said communication unit (50) is periodically activated, automatically, to synchronize the reference real time with said exact real time during a said. synchronization phase. 30. 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 the synchronization of 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 of the reference real time with said exact real time during a said synchronization phase. 31. Timepiece according to claim 30, characterized in that said member for synchronizing the reference real time on said exact real time is formed by a crown associated with a control rod which also serve for setting. the actual time of the display manually. 32. 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 the mechanical resonator 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. 33. Timepiece according to claim 32 wherein the horological movement comprises an escapement associated with the mechanical resonator; characterized in that the braking device comprises an actuator (174) provided with a stop member (184) for the oscillating mechanical resonator, the stop member being operable between a position of non-interaction with the mechanical resonator and an interaction position in which this stop member forms a stop for a protruding part (190) of the oscillating mechanical resonator, the protruding part being arranged to abut against the stop member when the latter is in its interaction position , the stop member in its interaction position and the protruding part defining a stop position (θB) for the oscillating mechanical resonator which is different from its neutral position, corresponding to the state of minimum potential energy of the mechanical resonator , and less than a minimum amplitude of the oscillating mechanical resonator in its useful operating range, said stop position being further provided so that the mechanical resonator oscillates lant is stopped by the stop device outside a coupling zone (θZI) of the exhaust 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. 34. 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 mechanical resonator 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 its interaction position while the oscillating mechanical resonator is located on the side of its neutral position relative to said stop position, and so that the actuator then maintains the stop member in this interaction position for a determined duration which is sufficient for the projecting part of the oscillating mechanical resonator to abut at least once against the stop member. 35. 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 supply of 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. 36. 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 circuit d 'clock (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 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 to or greater than said overall time error determined beforehand by the electronic correction circuit. 37. 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 the control unit comprises a device for generating at least one frequency (62) which is arranged so as to be able to generate a first periodic digital signal (SFS) at a frequency FSUP; 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 (SC1, SAct (SFS)) derived from the first periodic digital signal, during a first correction period, to activate the braking device so that this braking device generates a first series of pulses periodic braking which are applied to the mechanical resonator at said FSUP frequency, the duration of the first correction period and therefore the number of periodic braking pulses in said first series being determined by said delay to be corrected; and in that the frequency FSUP is provided and the braking device is arranged so that said first series of periodic braking pulses at frequency FSUP can generate, during said first correction period, a first synchronous phase in which the oscillation of the mechanical resonator (14) is synchronized to a correction frequency FScor which is greater than a reference frequency F0c provided for the mechanical resonator. 38. 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 (SFI ) at a FINF frequency; 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 (SAct (SFI)) derived from the second periodic digital signal, during a second correction period, to activate the braking device so that this braking device generates a second series of periodic braking pulses which are applied to the mechanical resonator at said frequency FINF, the duration of the second correction period and therefore the number of periodic braking pulses in said second series being determined by said advance to be corrected; and in that the FINF frequency is provided and the braking device is arranged so that said second series of periodic braking pulses at frequency FINF 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 FICor which is lower than the reference frequency FOc provided for the mechanical resonator. 39. Timepiece according to claim 37, wherein the horological movement comprises an escapement associated with the mechanical resonator; characterized in that said FSUP frequency and the duration of the braking pulses of the first series of periodic braking pulses are selected such that, during said first synchronous phase, the braking pulses of said first series each occur out of a coupling zone (θZI) between the oscillating mechanical resonator and the exhaust. 40. Timepiece according to claim 38, wherein the horological movement comprises an escapement associated with the mechanical resonator; characterized in that said frequency FINF and the duration of the braking pulses of the second series of periodic braking pulses are selected such that, during said second synchronous phase, the braking pulses of said second series each occur outside a coupling zone (θZI) between the oscillating mechanical resonator and the exhaust. 41. 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 signal. periodic digital (SF0c) at the reference frequency FOc for the mechanical resonator; in that the control unit is arranged to be able to supply the braking device with a third control signal (SAct (SF0c)) derived from the third periodic digital signal, during a preliminary period preceding the correction period, to activate the control device braking so 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 (θZI) 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 is triggered, 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 at such that said first phase synchronous with said correction frequency FSC starts from said first braking pulse or a second braking pulse. 42. 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. 43. Timepiece according to claim 42, characterized in that said correction period has a duration substantially equal to said advance to be corrected. 44. Timepiece according to claim 42 or 43, characterized in that the locking device is formed by a separate device (114) from said braking device and comprises a bistable latch (115), the first stable position of this latch bistable corresponding to a position of non-interaction with the mechanical resonator and its second stable position corresponding to a stop and blocking position of the mechanical resonator. 45. 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 being inserted into a hollow (108), arranged in a circular element (100) of the balance forming the mechanical resonator, when the blocking device is activated to block this mechanical resonator during the period of correction of a given advance.