CLOCK WITH MICROGENERATOR AND LIGHT SOURCE

Description

Technical field of the invention

[0001] The invention relates to the field of timepieces, in particular those equipped with a mechanical movement, comprising a micro-generator for supplying energy to particular circuits, in particular lighting means. Technological background

[0002] On the market there have already been mechanical watches with various additional lighting systems. In a particular embodiment, disclosed in document EP 3838424, a lighting device is powered by a micro-generator, also called a 'generator', whose rotation is ensured by a barrel spring, this lighting device being arranged on a fixed support of the watch movement in a region located at the periphery of the rotor of the micro-generator. The coils of the micro-generator are carried by its stator while the rotor conventionally carries permanent magnets.

[0003] Known lighting systems have major drawbacks for a watch with a mechanical movement, especially for a high-end watch for which it is important to preserve the mechanical character of the watch as much as possible.Indeed, these known lighting systems are provided with at least one electroluminescent element, an electronic circuit and an electrical circuit which are arranged on a fixed support at the periphery of the rotor of the micro-generator, which on the one hand introduces a device of the electronic type into the watch and, on the other hand, extends the lighting device itself (i.e. the elements involved in the generation of light) beyond the horizontal surface defined by the rotor, firstly by the extent of the stator coils and then by the arrangement of said at least one electroluminescent element, the electronic circuit and the electrical circuit (generally a PCB) which connects the electronic circuit on the one hand to the coils and on the other hand to said at least one electroluminescent element.All these stationary electrical and electronic parts occupy a relatively large surface area beyond the surface defined by the rotor of the micro-generator, in addition to accentuating, for a consumer, a hybrid character of the watch. Summary of the invention

[0004] The invention proposes to solve in particular the problems of the prior art indicated above. Other objectives will also emerge from the description of the invention which follows.

[0005] To this end, the invention relates to a timepiece according to claim 1, which comprises a micro-generator comprising a rotor, carrying at least one coil and at least one light-emitting diode powered by at least one said coil, and a stator comprising permanent magnets.

[0006] According to a first characteristic of the invention, the rotor carries all of the electrical and electronic equipment formed by said at least one light-emitting diode, said at least one coil and, where appropriate, an electrical and / or electronic circuit arranged between said at least one coil and said at least one light-emitting diode.

[0007] According to an advantageous characteristic, the permanent magnets are located, in axial projection, inside a circular surface defined by the rotor as it rotates.

[0008] According to another advantageous characteristic, at least one said light-emitting diode, preferably said at least one light-emitting diode, is powered directly by at least one said coil during its rotation relative to the stator of the micro-generator. Brief description of the figures

[0009] The aims, advantages and characteristics of the invention will appear better on reading the detailed description which follows, and with reference to the appended drawings, where: there figure 1represents, schematically and in perspective, an example of application of the invention to a watch comprising a lighting device: in the left part of the figure is visible a barrel, which supplies, through a gear train, a micro-generator, which comprises a rotor mobile in rotation facing a stator; the micro-generator carries at least one light-emitting diode which is supplied by at least one coil, and which is mounted on the rotor, eccentric with respect to the axis of rotation of the rotor, while the stator carries permanent magnets; this rotor carries a ratchet, which cooperates with a pawl to release or block its rotation, the arrow schematically indicates a device for actuating the pawl which is mobile in rotation to stop and release the generator; the Figure 2A represents, in a schematic and perspective way, the micro-generator of the figure 1: the two rings of the stator carry permanent magnets, in alternating polarities, and, in their air gap, the rotor carries coils; the arrows show the alternating directions of the magnetic field, in the same direction parallel to the axis of rotation of the rotor; the latter carries two light-emitting diodes mounted in symmetry with respect to this axis of rotation, and both eccentric; the Figure 2B is a top view of the micro-generator of the figure 1 ; there figure 3 represents, in a schematic and exploded perspective, the micro-generator of the figures 1 And 2A, 2B : the rotor disc carries 12 coils, we see the double row of 12 magnets of the stator rings, and the eccentric position of the light-emitting diodes; the figure 4 represents, schematically and in top view, according to the direction of the axis of rotation, the rotor of the micro-generator of the figures 1 to 3; we see the connection of the coils between them and with the light-emitting diodes; an axial hub supports the rotor, and also carries an openwork ring comprising eight openings to let the light emitted by each light-emitting diode pass towards a device for illuminating the timepiece; the Figure 5 is a section, along line VV, passing through the axis of rotation of the micro-generator of the figures 1 to 4 ; in this advantageous but non-limiting example, the dimensions of the micro-generator are very small, with a stator cage of diameter 8.4 mm, and thickness of 1.4 mm; the figure 6 represents, schematically and in section, passing through the axis of rotation of the micro-generator of the figures 1 to 5, the device for illuminating the timepiece according to the invention, illustrated for the particular and non-limiting case of illuminating an annular zone of a watch dial shown in the upper part of the figure with an opaque central part and a transflective annular peripheral part, and which comprises, under the latter, a stationary light guide structure, which itself is located above the light micro-generator, hidden here, in a non-limiting manner, by the opaque part of the dial.This stationary light guide structure comprises, under the opaque part and under the transflective part of the dial, a light guide which comprises, on the one hand, an introduction and injection zone superimposed on the trajectory of each light-emitting diode during the rotation of the rotor of the micro-generator and arranged to introduce light emitted by each light-emitting diode into the light guide, symbolized by a first arrow in the light guide, and on the other hand an exit and extraction zone of the light from the light guide, symbolized by a second arrow on the periphery, under a transflective part of the dial. Above the micro-generator and the first arrow, there is a zone hidden by an opaque part, from which two small arrows depart, and which is a coupling zone, structured with a diffusive profile, to carry out remote optical coupling between the light guide and the light-emitting diode.Next to this coupling zone, and further to the periphery, the output and extraction zone comprises an extraction structuring zone with a distribution of small juxtaposed reflective patterns, to extract the light from inside the light guide and distribute it substantially uniformly towards the visible part to be illuminated; the . figure 7 represents, schematically, an equivalent electrical circuit of the proposed device, with a micro-generator, generating an alternating signal, which is connected in parallel with two light-emitting diodes in reversed polarity. In this way, during the alternation of the signal, one or the other of the diodes will emit light. For frequencies above 30 Hz, the eye no longer distinguishes this alternation and perceives the two diodes lit at the same time; the figure 8 represents the shape of the current (on the ordinate) in the light-emitting diodes, as a function of time (on the abscissa), for rotation at 150 Hz; the figure 9 represents the shape of the average current (on the ordinate) in the light-emitting diodes as a function of the rotation frequency (on the abscissa) of the rotor; the figure 10 represents the shape of the average braking torque applied to the rotor (on the ordinate) by the light-emitting diodes as a function of the rotor rotation frequency (on the abscissa); the figure 11 represents, schematically, a variant of the circuit equipping the rotor, where each light-emitting diode is supplied indirectly from the coils, through an electrical and / or electronic circuit which includes a Graetz bridge rectifier and an output capacitor of this rectifier; the figure 12 is a diagram illustrating the evolution of the voltage, over time, at the terminals of the light-emitting diode depending on the connection of the figure 11 ; there figure 13is a curve showing the influence of the thickness of the coil wire (on the abscissa) on the resistance of the coil (on the ordinate); the figure 14 is a curve showing the influence of the thickness of the coil wire (on the abscissa) on the current in the light-emitting diodes (on the ordinate); the figure 15 is a curve showing the influence of the thickness of the coil wire (on the abscissa) on the induced voltage (on the ordinate); the figure 16 is a curve showing the influence of the thickness of the coil wire (on the abscissa) on the total discharge time of the barrel (on the ordinate); the figure 17 represents, schematically, a timepiece which includes a device for releasing and stopping the micro-generator associated with a control device actuable by a user, to trigger the drive of the rotor of the micro-generator, or with an engagement mechanism incorporated in the watch movement. Detailed description of the invention

[0010] The invention proposes to use a light micro-generator for lighting a particular area of a timepiece, which is described below with reference to the appended figures.

[0011] The invention relates to a timepiece 1000, comprising a micro-generator 100 of the watchmaking type. This micro-generator 100 is formed of a stator 20 comprising permanent magnets 25 and a rotor 10 comprising coils 11 and at least one light-emitting diode 31, 32, which is powered, directly or indirectly through an electrical and / or electronic circuit 37, 38, by at least one of the coils 11 which provides an induced electric current during its rotation relative to the stator 20. According to the invention, the rotor 10 carries all of the electrical and electronic equipment formed by said at least one light-emitting diode, the coils and, where appropriate, said electrical and / or electronic circuit arranged between said at least one of the coils and said at least one light-emitting diode (also called 'LED' hereinafter).

[0012] Advantageously, the permanent magnets 25 are located, in axial projection in a direction parallel to the axis of rotation of the rotor 10, inside a circular surface defined by the rotor 10 when it rotates.

[0013] THE figures 1 to 5 illustrate a rotor 10 comprising coils 11, in particular flat coils (pancakes), and a stator 20 comprising an annular base 21, with an L-shaped radial section, carrying a first part of the permanent magnets 25, and an annular flange 22 for closing the annular base and carrying a second part of the permanent magnets 25. The annular base and the annular flange form a stator cage with a C-shaped radial section with three straight portions. The micro-generator 100 has a diameter generally between 6 mm and 15 mm.

[0014] The annular base 21 and the flange 22 are preferably made of a ferromagnetic material forming an external closure for the magnetic field of the permanent magnets 25, which are axially magnetized and arranged on the inner side of the stator cage, opposite the coils 11 of the rotor 10. More generally, the coils 11 and the permanent magnets 25 are arranged so that the coils pass at least partially above the permanent magnets when the rotor 10 rotates, driven directly or indirectly by a barrel 200 or by any suitable drive means. We therefore have a micro-generator 100 of the type with axial magnetization of the permanent magnets 25 and a “three-level” structure with the rotor 10 carrying the coils 11 placed in the intermediate level, in the space between two levels of permanent magnets 25 located respectively on the two axial sides of the coils 11.The axially facing magnets 25 have the same polarity, two adjacent magnets on the same level have opposite magnetic polarities. Thus, conventionally, for each of the two levels of magnets, the polarities are alternated.

[0015] In a preferred variant, and as seen in the figure 4 , at least one light-emitting diode 31, respectively 32 is powered directly by at least one coil 11 during its rotation relative to the stator 20 of the micro-generator 100, without electrical and / or electronic circuit between said at least one light-emitting diode and said at least one coil, with the exception of contact pads and two circular tracks, for example made of gold, in particular without capacitor and / or other electrical and / or electronic components.

[0016] In another variation, and as seen in figure 11, at least one said light-emitting diode 31, 32, is powered indirectly, through the electrical and / or electronic circuit which comprises a Graetz bridge rectifier 37 and an output capacitor 38 of this rectifier, by at least one coil 11 supplying an induced electric current during its rotation relative to the stator 20, of the micro-generator 100.

[0017] More particularly, and as visible on the figures 1 to 5 , the rotor 10 carries a pair of light-emitting diodes 31, 32, preferably diametrically opposed, arranged in polarities opposite each other.

[0018] More particularly, in a variant not illustrated, the rotor 10 carries four light-emitting diodes (also called 'LEDs') at 90°, arranged two by two in reverse polarities (preferably two diametrically opposed LEDs having the same polarity).

[0019] According to an advantageous variant, any electrical and / or electronic device that the timepiece comprises is embedded on the rotor 10 of the micro-generator 100. A mechanical timepiece thus escapes any wiring or means of transferring electrical energy outside the rotor 10.

[0020] In particular, and as visible on the figures 1 to 5, the rotor 10 and the stator 20 are mounted coaxially around an axis of rotation D of the micro-generator 100, and said at least one light-emitting diode 31, 32 is mounted eccentrically relative to said axis of rotation D, each light-emitting diode 31, 32 thus describing an annular surface during the rotation of the rotor 10. And said at least one light-emitting diode 31, 32 is arranged to provide at least a major portion of the light 70 that it emits to at least one portion of the timepiece 1000 visible to a user of this timepiece, so as to illuminate this at least one visible portion.

[0021] Thus, the light-emitting diodes 31, 32 are arranged on the rotor 10 to obtain the best result, and the outer structure on the light-emitting side must be perforated to allow the emitted light 70 to pass through most of this outer structure, preferably so that substantially all of the emitted light can pass through this outer structure.

[0022] Also, more particularly, as visible on the figures 4 And 5, the rotor 10 comprises a hub 19 which comprises a drive pinion 19a and which carries a lower annular structure 52, a disc 54, for example made of ceramic, forming a support for the coils 11 arranged in peripheral openings of this disc and for the two LEDs 31, 32 arranged in two respective openings 55 of the disc, and a toothed wheel 18 located above the emission surfaces of the LEDs 31, 32 and comprising openings 17 configured to allow the light 70 emitted by each of these LEDs to pass through to means for guiding this emitted light towards said at least one visible part of the timepiece. The toothed wheel 18 is a ratchet forming a device for locking and releasing the micro-generator 100. The lower annular structure 52 is preferably opaque and without opening, so as to mask the openings 55, the contact pads 65, the drops of glue 68 and the circular tracks 66.The contact pads 60 and the connections of the coils 11 to these contact pads are hidden from the view of an observer by the base 22 of the stator cage. Thus, apart from a small portion of the two contact pads 64 possibly visible through the circular slot located between the annular structure 52 and the base 22, the light micro-generator 100 does not reveal any electrical or electronic element, except for the emission surfaces of the LEDs, which have a noble appearance and are located in an internal region of this light micro-generator. Such a construction is particularly well suited to a lighting device incorporated in a high-end mechanical movement. In addition, the electrical connections can be provided in gold.

[0023] The rotor 10 is driven by a barrel 200, through a barrel train 300. As indicated, the micro-generator 100 is equipped with a rotor locking and releasing device 400 which comprises the ratchet 18 and a pawl 92, this device making it possible to activate the micro-generator on demand in the manner of a speed regulator in a musical or striking watch. It is used to start the rotation of the micro-generator on demand and then to stop it. It is therefore possible to briefly switch on several times the intended lighting system (light micro-generator) on a barrel load.

[0024] The rotor 10 comprises a module composed of the support disc 54 (in particular made of ceramic material) which carries a certain number of small coils 11 at its periphery as well as at least one light-emitting diode, in particular two LEDs 31, 32. The rotation of the coils 11 in the magnetic field of the magnets 25 of the stator 20, generates an induced voltage and thus an alternating induced current, which supplies the light-emitting diodes according to the equivalent electrical diagram given in figure 7The coils 11 are connected in series, with alternating polarities, the inner end 61 and the outer end 62 of each coil being connected respectively to two contact pads 60 formed on the support disc 54. This plurality of coils is connected to the two LEDs, in particular via a printed circuit which is made up of two contact pads 64 for two respective ends of two end coils of the series of coils and for an electrical connection 67 of the first LED 31 to these coils, of two contact pads 65 for the electrical connection 67 of the second LED 32, and of two circular tracks 66 connecting the two contact pads 64 respectively to the two contact pads 65. The two LEDs 31, 32 are arranged in reverse polarization in order to exploit the alternation of the electric current generated in this system of direct power supply of the LEDs by the coils 11.In the advantageous variant shown, the contact pads 64 and 65 and the two circular tracks 66 are directly printed / deposited on the support disc. Thus, no conventional PCB made of synthetic material is necessary. Note that the electrical connections 67 are protected by drops of glue 68 which also serve to fix the LEDs in the respective openings 55 of the support disc 54.

[0025] We can therefore operate with an electrical circuit as simple as the one shown in the figure 7 .

[0026] The current i LED over time flowing in each light-emitting diode 31, 32 then takes the form visible on the figure 8 .

[0027] What matters for the rotation frequency of the micro-generator is the average current i LED MOY , represented on the figure 9 , which results in an average braking torque applied to the rotor CM FR as shown in the figure 10 .

[0028] In a particular example, the barrel initially delivers 20 µN·m to the rotor, and we have an initial rotation speed of approximately 140 Hz, which decreases with the discharge of the barrel. Without power dissipated by the light-emitting diodes (LEDs), the assembly would rotate much faster. Concerning the voltage induced in the coils, if we note: Ku the induced voltage coefficient for a coil (max value of the voltage induced in a coil), n BOB the number of coils, ω the rotation speed (rad / s), and considering all the coils alternating in series, the induced voltage is V IND : V IND = ω ⋅ n BOB ⋅ K U ⋅ sin ω ⋅ n BOB / 2 ⋅ t

[0029] In fact, the electrical pulsation is equal to n BOB / 2 multiplied by the rotation speed ω, because the induced voltage is the derivative of the variation in magnetic flux, which passes once from + to - and the next time from - to +. The induced voltage is therefore a linear function of the rotation speed and therefore of the rotation frequency.

[0030] As for the relationship between induced voltage and current in the light-emitting diode, it is given by the Shockley equation, where Vt is 26mV at room temperature and n is a quality parameter between 1 and 2: I = IS ·(e VIND / nVt< - 1).

[0031] The dimensions of the magnets and coils are optimized, as seen in Figure 5 , for a relatively small stator cage, with an outside diameter of 8.4 mm, and a total thickness excluding the hub of only 1.4 mm.

[0032] The number of turns and the diameter of the wire are adapted to ensure the operation of the light-emitting diodes. Another number of coils, magnets and different dimensions are entirely possible. Increasing the volume of the magnets 25, or reducing the air gap, allows the coupling between coils 11 and magnets 25 to be increased. In order to maximize the flux variations, the magnets 25 and the coils 11 are brought as close as possible to each other. Concerning the coils 11, increasing their volume or reducing the diameter of the wire allows the induced voltage coefficient Ku (defined as the ratio of the induced voltage to the rotation speed) to be increased but also increases the resistance of the coil. In this case, the current intensity in the light-emitting diodes is reduced but the rotation speed of the rotor is also reduced, thus increasing the discharge time of the barrel and the lighting time. figures 13 to 16show the effects of coil wire thickness 11 on resistance ( figure 13 ), on the current in the diodes ( figure 14 ), on the induced voltage ( figure 15 ), and on the total discharge time of the barrel ( figure 16 ).

[0033] Thus, by choosing a wire diameter of 14 µm, we obtain a rotor speed of 120 revolutions per second, barrel loaded, which, with a power reserve of around 5500 revolutions relative to the rotor, allows illumination of more than 40 seconds.

[0034] The next step is to make the best use of this light energy potential to effectively illuminate an area of the 1000 timepiece, visible to the user.

[0035] As explained above, the rotor 10 carries an openwork wheel 18 comprising openings 17 to allow the light 70 emitted by each light-emitting diode 31, 32 to pass through, towards means for guiding this emitted light towards at least one visible part of the timepiece.

[0036] The timepiece 1000 comprises, in the vicinity of the micro-generator 100, at least one stationary light guide structure 40, which is arranged to collect, for any angular position of the rotor when the latter is rotating, said at least a major part of the light emitted by each light-emitting diode 31, 32, and to then guide this emitted light towards this at least one visible part of the timepiece, so as to obtain an illumination of this visible part that is substantially constant and / or substantially uniform when this at least one light-emitting diode is emitting.

[0037] More particularly, this at least one stationary light guide structure 40 comprises at least one light guide 45 which comprises, on the one hand, at least one introduction and injection zone 41 superimposed on the trajectory of the light emitted by the light-emitting diode 31, 32, during the rotation of the micro-generator 100 and arranged to introduce this emitted light into this light guide 45, and on the other hand, at least one exit and extraction zone 42 for the light introduced into the light guide from this light guide 45; this at least one exit and extraction zone 42 is arranged so as to obtain specific illumination of this at least one visible part of the timepiece 1000.

[0038] More particularly, said at least one introduction and injection zone 41 faces the light emission zone of the light-emitting diode 31, 32, and comprises at least one coupling structuring zone 805. This coupling structuring zone 805 is structured with a diffusive rough profile, which is arranged to couple the light inside the light guide 45, so as to carry out a remote optical coupling between the light guide 45 and said at least one light-emitting diode 31, 32, some light rays of which are deflected in an acceptance cone of the light guide 45 and remain guided by total reflection inside the light guide 45 until their incidence on the at least one exit and extraction zone.

[0039] More particularly, said at least one exit and extraction zone 42 comprises at least one extraction structuring zone 804, which has a distribution of small distinct reflective patterns, each with a diameter of less than 0.2 mm, and which is provided for extracting the light introduced into the light guide 45 and distributing it substantially uniformly towards said at least one visible part of the timepiece 1000.

[0040] More particularly, said at least one introduction and injection zone 41 and said at least one exit and extraction zone 42 are not superimposed in projection in a plane perpendicular to the axis of rotation D of the micro-generator 100.

[0041] The advantage of a particular arrangement of the light guide 45 is understood, so as to collect the light in this guide for any angular position of said at least one light-emitting diode 31, 32.

[0042] A preferred variant comprises complete masking of the ring of light generated by each light-emitting diode 31, 32. Thus, more particularly, the light-emitting zone of said at least one light-emitting diode 31, 32 is masked from the view of the user of the timepiece 1000 by an opaque part 801.

[0043] We can also choose another variant with a different optical effect, to highlight the fact that the light source is globally annular, in this case we will not mask the ring of light.

[0044] More particularly, said at least one stationary light guide structure 40 capable of diffusing the light coming from the light-emitting diode 31, 32, to provide indirect illumination of a part of the timepiece 1000, comprises at least one transflective part 802 at the level of said at least one visible part of the timepiece 1000.

[0045] More particularly, said at least one extraction structuring zone 804 is structured so that the extraction is not uniform, with the extracted light intensity coefficient per unit area not having a constant value over the entire area.

[0046] More particularly, said at least one extraction structuring zone 804 is configured such that the extracted light intensity is substantially constant.

[0047] More particularly, the timepiece 1000 comprises at least one dial 800, a first part of which is such a visible part of the timepiece and is illuminated by at least one transflective part 802 of said at least one stationary light guide structure 40, and a second part of which is hidden by an opaque part 801 of said at least one stationary light guide structure 40. More particularly and non-limitingly, this opaque part 801 hides said at least one micro-generator 100 and each light-emitting diode 31, 32.

[0048] More particularly, the illumination of a dial is carried out by a sapphire light guide structure and a light micro-generator, i.e. comprising a light source, as presented above.

[0049] A special optical system was developed for illuminating the perimeter of a dial in the dark. The method consisted of modeling the system, for example using the "Backlight Optimization ®<" module of the "Lighttools ®<" raytracing software, or similar. First, we defined the properties of the light source. As described above, two light-emitting diodes are arranged in diametrically opposite positions on the rotor 10 of the micro-generator 100. When this rotor 10 rotates at high speed, these two light-emitting diodes 31, 32 also rotate, thus generating a light ring. The simulation thus used a static light ring as the light source.

[0050] As seen in figure 6, a sapphire light guide 45 is arranged below the dial 800. Sapphire is chosen because it is a suitable material for fine watchmaking. The light guide 45 is in the form of an annular disc, for example and not limited to a thickness of 0.4 mm, an external diameter of 38 mm and an internal diameter of 14 mm. This geometry was chosen in order to constrain the light to circulate around the periphery of the part and therefore to be concentrated in the area to be illuminated. The face below the disc (the one opposite the micro-generator 100) has two types of structuring: coupling structuring zone 805 and extraction structuring zone 804.

[0051] The coupling structuring area 805 is structured with a diffusive rough profile, the function of which is to couple the light inside the disk. The fact that the light sources are in motion prevents close optical coupling with the light guide. This is therefore done at a distance. When crossing the coupling area, some rays coming from the light ring are deflected into the acceptance cone of the sapphire light guide 45 and remain guided by total reflection inside it. The dimension of the coupling area is adapted to the dimensions of the micro-generator 100 and the distance between it and the light guide 45. It is useless, or even disadvantageous, to widen the coupling area beyond the surface of the guide invested by the light cone. In fact, the coupling structure can also contribute to the extraction of light to the detriment of the total brightness of the area that we wish to illuminate.

[0052] The second surface structuring is the extraction structuring zone 804, characterized by a distribution of small reflective patterns, including but not limited to circles, approximately 0.12 mm in diameter, and has the function of extracting light from inside the light guide 45 by distributing it uniformly all around the part. The distribution of the reflective patterns is calculated by the software algorithm. This distribution of the reflective patterns is not uniform, and the density varies locally so that the extracted light is the same all around the part and thus uniform. The starting point of the calculation is a uniform density of circles distributed in the area that is to be illuminated. Then the software algorithm seeks a pattern density distribution such that the light is extracted uniformly around the entire periphery of the disk.In calculating this distribution, the software takes into account the geometry of the light guide, the material from which it is composed, the area of injection of the light into this light guide and the incident light distribution on this injection area. The advantage of this method of calculating the matrix of patterns, in particular small distinct circles, lies in the fact that the uniformity of the illumination is normally ensured independently of the actual reflectivity properties of the patterns.

[0053] If the patterns have low reflectivity, the total amount of extracted light will be low. If the patterns have high reflectivity, the total amount of extracted light will be high. But in both cases, the uniformity of the illumination will be the same. The light extracted from the guide passes through the peripheral area of the dial and illuminates it from behind. For this, the dial will be made of a transflective material such as a thin white ceramic, or as more commonly used in watchmaking, an enameled ceramic.

[0054] The light guide surface structures described above are difficult to achieve mechanically on a hard material like sapphire. However, they are quite feasible with pico- and femto-laser machining.

[0055] It is understood that, for a good result, the light extraction zone must be configured so that the extraction is not constant, that is to say that the coefficient of light intensity extracted per unit area is not a constant coefficient, given that the light is injected locally into the light guide. It is advantageous to configure the structure of the light extraction zone so that the extracted light intensity is substantially constant.

[0056] Very different usage configurations are possible, because the optical system developed for the invention allows a significant offset between, on the one hand, the light source constituted by the ring of light emitted by each light-emitting diode, and on the other hand a visible area to be illuminated, which can be relatively far from the micro-generator in the timepiece.

[0057] For example, it is possible to choose a lighting configuration for a dial 800, with at least one area of the dial 800 illuminated, the light guide 45 being arranged under this dial 800. It is also possible to produce a light ring superimposed on an hour marker and / or on a time scale.

[0058] Advantageously, the timepiece 1000 comprises at least one control device 400 for the micro-generator 100, allowing the release and stopping on command of this micro-generator via a device for blocking and releasing the rotor 10 that this control device comprises. The control device 400 can be actuated by a user to trigger the driving of the rotor 10 of the micro-generator 100 and then to stop it, this control device comprising an external control member, in particular a push button or a bolt. In another embodiment, the control device comprises a triggering mechanism 500 actuable by the watch movement 600 that the timepiece 1000 comprises. These mechanisms are well known in striking or repeating watches. The user can in particular release the micro-generator by pressing a push button actuating a lever.The light remains on until the push button is released. In the other embodiment mentioned above, the mechanism for engaging the watch movement acts, for example, on the same lever, in particular by means of an intermediate lever, preferably for a determined period of time. Any similar system can be imagined for switching the light on and off on command. In particular, the various mechanisms provided are arranged to momentarily release the pawl 92 from the ratchet 18 and thus allow the rotor 10 to rotate.

[0059] More particularly, the timepiece 1000 comprises at least one drive mechanism which is arranged for driving the rotor 10 of the micro-generator 100.

[0060] The advantages of the invention are multiple.

[0061] The arrangement of the light-emitting diodes directly on the micro-generator eliminates the need for friction contact connections, conductive wires, or printed circuit or PCB tracks. This ensures compatibility with high-end watchmaking. Their advantageous arrangement on the rotor avoids the presence of any electronic component composed of materials incompatible with a high-end mechanical watch. The light-emitting diodes are then the only components that can be described as "electronic," but their composition is inorganic, and the vast majority of the volume is composed of crystal and metal. As a result, the proposed arrangement is aesthetically discreet and also compatible with a skeleton watch construction with a visible system.

[0062] Powering one or more light-emitting diodes is possible without using a battery. It is certainly possible to use a smoothing capacitor embedded in the rotor, but this does not seem necessary because the rotor rotates at a relatively high speed so that the periodic variation in brightness is not perceptible to the human eye. Indeed, the preferred embodiment of the invention offers the advantage of presenting a passive circuit without any intermediate energy storage, thanks to the power supply of each diode directly by the coils, without necessarily requiring an induced voltage rectifier or smoothing capacitor.The light-emitting diode has no persistent brightness when the current turns off, but the user's eye sees persistent lighting, because, with a rotation of the order of a hundred hertz and for example 12 or 14 poles in the micro-generator, we have a flashing of the order of a kHz, imperceptible to the eye. As for the rotation of the micro-generator, small braking torques a thousand times per second will act as a smoothing on the rotation speed. An energy storage capacitor is not desirable, because it would not have a voltage variation that follows the induced voltage variation quickly enough, and would have low efficiency for speed regulation.

[0063] The solution without electronics other than a possible Graetz bridge (passive) embedded on the rotor, and without any accumulator, guarantees full compatibility with high-end watch construction.

[0064] The ability to turn the light function on and off after a desired time is very advantageous. This option is not possible in watches known from the prior art.

[0065] When light-emitting diodes (LEDs) rotate at high speed, they generate an annular light distribution that is almost continuous and uniform for the human eye and whose surface extension is much greater than that of a light-emitting diode. In addition, the arrangement of a light guide with a coupling zone arranged to collect the light from the light ring generated by the LEDs when the rotor rotates is very advantageous because this makes it possible to transform a light ring into a specific illumination of at least one visible part of the watch other than said light ring, which is preferably masked from the direct view of an observer, and to further promote the constancy of the illumination produced.

[0066] The use of the light micro-generator in combination with a remote light guide in order to distribute the light elsewhere in the watch is very advantageous, this allowing a playful (light decorations) or functional (reading the time or any other display) lighting effect, thanks to one or more light extracting zone(s) of the light guide, arranged so as to preferably obtain a substantially uniform extraction of a visible luminous surface, in particular for the illumination of a ring of the dial of a watch comprising a time scale. Nomenclature

[0067] D axis of rotation of the micro-generator 10 rotor 11 coil 17 opening in ratchet 18 ratchet 19 hub 19a pinion 20 stator 21 annular stator cover 22 annular stator base 25 permanent magnet 31, 32 light-emitting diode (LED) 37 Graetz bridge 38 output capacitor of the Graetz bridge 40 stationary light guide structure 41 introduction and injection zone 42 exit and extraction zone 45 light guide 52 annular rotor structure 54 rotor support disc 55 opening in the support disc 60 contact pad 61, 62 end part of the coils 64, 65 contact pad 67 electrical connection of the LEDs 68 resin drop 70 emitted light 100 micro-generator 200 barrel 300 barrel gear train 400 control device 500 engagement mechanism 600 movement 800 dial 801 opaque part 802 transflective part 1000 timepiece

Claims

1. A timepiece (1000) comprising a microgenerator (100), formed by a stator and by a rotor and comprising at least one coil (11) and permanent magnets (25), and at least one electroluminescent diode (31, 32) which is powered by said at least one coil (11) directly or indirectly via an electrical and / or electronic circuit (37, 38) ; characterised in that the stator carries said permanent magnets and the rotor carries said at least one coil that powers an electric current induced when it rotates relative to the stator (20) ; and in that the rotor (10) carries all of the electrical and electronic equipment formed by said at least one electroluminescent diode, said at least one coil and, as the case may be, said electrical and / or electronic circuit.

2. The timepiece (1000) according to claim 1, characterised in that said permanent magnets are located, in axial projection, inside a circular surface defined by said rotor when it turns.

3. The timepiece (1000) according to claim 1 or 2, characterised in that at least one said electroluminescent diode (31, 32) is directly powered by at least one said coil (11) when it rotates relative to the stator (20) of the microgenerator (100).

4. The timepiece (1000) according to claim 1 or 2, characterised in that at least one said electroluminescent diode (31, 32) is indirectly powered, via said electrical and / or electronic circuit which comprises a Graetz rectifier bridge (37), by at least one said coil (11) providing an electric current induced when it rotates relative to the stator (20) of the microgenerator (100).

5. The timepiece (1000) according to any of claims 1 to 4, characterised in that the rotor (10) carries at least one pair of said electroluminescent diodes (31, 32), preferably diametrically opposed, arranged in reverse polarities to each other.

6. The timepiece (1000) according to any of claims 1 to 5, characterised in that any electrical and / or electronic system comprised in the timepiece is mounted on said rotor (10) on the microgenerator (100).

7. The timepiece (1000) according to any of claims 1 to 6, characterised in that the rotor (10) and the stator (20) are coaxially mounted around an axis of rotation (D) on the microgenerator (100), and said at least one electroluminescent diode (31, 32) is eccentrically mounted relative to said axis of rotation (D), each electroluminescent diode (31, 32) thus describing an annular surface when the rotor (10) is rotating ; and in that said at least one electroluminescent diode (31, 32) is arranged to provide at least a major part of the light it emits to at least one part of the timepiece (1000) visible to a user of that timepiece (1000), so as to illuminate said at least one visible part of the timepiece (1000).

8. The timepiece (1000) according to claim 7, characterised in that the rotor (10) comprises a hub (19) which also carries a pierced bow (18) comprising openings (17) to allow the light emitted by said at least one electroluminescent diode (31, 32) to pass through towards means for guiding this emitted light towards said at least one visible part of the timepiece (1000).

9. The timepiece (1000) according to claim 7 or 8, characterised in that this timepiece comprises, in the vicinity of the microgenerator (100), at least one stationary light guide structure (40) arranged to collect, for any angular position of the rotor when the latter turns, said at least a major part of the light emitted by said at least one electroluminescent diode (31, 32) and then to guide this emitted light towards said at least one visible part of the timepiece, so as to achieve substantially constant and / or substantially uniform illumination of this visible part when said at least one electroluminescent diode is emitting.

10. The timepiece (1000) according to claim 9, characterised in that said at least one stationary light guide structure (40) comprises at least one light guide (45) comprising, on one hand, at least one introduction and injection zone (41) arranged to receive the light emitted by said at least one electroluminescent diode (31, 32) while said at least one microgenerator (100) is rotating and to introduce this emitted light into said light guide (45), and, on the other hand, at least one zone (42) in which the light introduced into the light guide exits and is extracted from this light guide, said at least one exit and extraction zone being arranged so as to achieve specific illumination of said at least one visible part of the timepiece (1000).

11. The timepiece (1000) according to claim 10, characterised in that said at least one introduction and injection zone (41) faces the light-emitting zone of said at least one electroluminescent diode (31, 32) and comprises at least one coupling structuring zone (805) arranged to couple the light inside said light guide (45), so as to enable remote optical coupling between said light guide (45) and said at least one electroluminescent diode (31, 32), with some of the light rays located in an acceptance cone of said light guide (45) being guided by total reflection inside said light guide (45) until their incidence on said at least one exit and extraction zone.

12. The timepiece (1000) according to claim 10 or 11, characterised in that said at least one exit and extraction zone (42) comprises at least one extraction structuring zone (804) which has a distribution of small distinct reflective patterns, each with a diameter of less than 0.2 mm, provided to extract the light introduced into the light guide (45) by distributing it substantially uniformly towards said at least one visible part of the timepiece (1000).

13. The timepiece (1000) according to claim 12, characterised in that said at least one extraction structuring zone (804) is structured so that the extraction is not uniform, with the coefficient of luminous intensity extracted per unit of surface area therefore not having a constant value over the entire surface.

14. The timepiece (1000) according to claim 13, characterised in that said at least one extraction structuring zone (804) is configured such that the luminous intensity extracted is substantially constant.

15. The timepiece (1000) according to any of claims 10 to 14, characterised in that said at least one introduction and injection zone (41) and said at least one exit and extraction zone (42) are not superimposed in projection in a plane perpendicular to the axis of rotation (D) of said microgenerator (100).

16. The timepiece (1000) according to claim 15, characterised in that the light-emitting zone of said at least one electroluminescent diode (31, 32) is masked from the view of the user of said timepiece (1000) by an opaque part (801).

17. The timepiece (1000) according to claim 16, characterised in that the timepiece comprises a dial (800) arranged above the stationary light guide structure (40) and a first part of which is a said visible part of said timepiece that can be illuminated by said stationary light guide structure (40) and a second part of which is said opaque part (801).

18. The timepiece (1000) according to any of claims 9 to 17, characterised in that said at least one stationary light guide structure (40) capable of diffusing light from said at least one electroluminescent diode (31, 32) to provide indirect illumination of part of said timepiece (1000) comprises at least one transflective part (802) in said at least one visible part of the timepiece (1000).

19. The timepiece (1000) according to any of claims 1 to 18, characterised in that the timepiece comprises a device for enabling and disabling said microgenerator (100), which comprises a control device (400) that can be actuated by a user to release the drive of said rotor (10) on the microgenerator (100), said control device (400) comprising a control organ and / or a button and / or a bolt, and / or an interlock mechanism (500) that can be actuated by a mechanism (600) comprised in said timepiece.

20. The timepiece (1000) according to any of claims 1 to 19, characterised in that the timepiece comprises at least one drive mechanism arranged to drive said rotor (10) on the microgenerator (100).